Class 8th NCERT Solutions
Developmental stages in human embryos: First appearance of large marsupials. Organs can be injured as a result of many complicating factors including: During the fetal period, the total body weight TBW increases from approximately 5 to g. Because the endothelial cells line every blood vessel they play an important role in the proper function of every organ in your body.
Macrophages contain numerous lysosomes which are used for breaking down ingested material. These lysosomes are usually inconspicuous by light microscopy but readily visible by electron microscopy. In macrophages which have been active and have accumulated indigestible residue, the lysosomes may be visible by light microscopy as brown intracellular granules, as in this image of lung macrophages "dust cells". Click here or on the image for a wider-field view and more information on lung macrophages.
Macrophages of liver Kupffer cells and lung dust cells were named prior to clear understanding that these cells belong to a more widely distributed cell type. The term reticuloendothelial system refers to the macrophages of the liver , spleen and lymph nodes i.
The name reflects former confusion about the distinction between endothelial cells and the scattered population of macrophages monocytes, histiocytes. Macrophages can be readily labelled experimentally through their phagocytosis of injected carbon particles. However, endothelial cells are also labelled by the same procedure.
Although endothelial cells are not dramatically phagocytotic, they do shuttle some materials across the endothelial lining via small endocytotic and exocytotic vesicles. Macrophages are mobile amoeboid movement over short distances within a local region of connective tissue.
Most ordinary connective tissue contains a standing population of resident macrophages. But when damage or infection requires reinforcements, monocytes can increase the macrophage population many-fold. Monocytes are circulating cells in the blood example at WebPath which can differentiate into macrophages when they enter connective tissue. Macrophages are among the most independent cells in the body.
Although they respond to the chemical signals which govern immune responses, individual macrophages are capable of crawling out of connective tissue, crossing the body's epithelium, and scavenging foreign material on exposed surfaces such as the alveolar lining of the lung and the conjunctiva of the eye. Macrophages can gather and fuse into giant cells at sites of damage or foreign material. For illustrations, see WebPath example 1 , example 2 , example 3. Mast cells are secretory alarm cells.
Upon the slightest disturbance, they release chemical signals which diffuse through the surrounding ground substance and trigger the process of inflammation.
Mast cells occur as small individual cells, scattered rather widely in ordinary connective tissue. The cytoplasm of mast cells is packed with secretory vesicles, which can be fairly conspicuous in high-quality light microscope preparations. The granules contain histamine , heparin, and various other chemical mediators whose release signals a number of physiological defense responses. Allergies are caused in part by inappropriate sensitivity of mast cells.
The name "mast cell" is a misnomer. The word "mast" refers to food. When first described, the secretory vesicles of mast cells were misinterpreted as evidence of ingestion by phagocytosis. So the name suggests a cell which has eaten its fill of "mast". Lymphocytes are small cells with round nuclei and minimal cytoplasm the example shown here is from a blood smear. Some lymphocytes circulate throughout the body, moving freely from blood to ordinary connective tissue and back again.
Lymphocytes occur as inconspicuous individual cells scattered through most ordinary connective tissues. They are especially common in lamina propria i. Microscopically conspicuous accumulations of lymphocytes occur in scattered sites around the body, with special concentrations in spleen , thymus , lymph nodes , Peyer's patches of ileum, and tonsils. These sites include germinal centers where activated lymphocytes proliferate. Lymphocytes manufacture antibodies, proteins which possess the ability to recognize and bind to foreign substances.
The antibodies may be either secreted or bound to the lymphocyte membrane. Plasma cells are differentiated lymphocytes which are specialized to manufacture and secrete relatively large amounts of antibody. Electron micrograph at WebPath. The extracellular matrix of connective tissue is composed of ground substance and fibers. In ordinary connective tissue, the ground substanc e consists mainly of water.
The principal fiber type is collagen the most abundant protein in the body , with elastic fibers as a minor element. The extracellular materials which comprise the matrix are produced by fibroblasts.
More at Biochemistry website. Ground substance is the background material within which all other connective tissue elements are embedded.
In ordinary connective tissue, the ground substance consists mainly of water whose major role is to provide a route for communication and transport by diffusion between tissues. This water is stabilized by a complex of glycosaminoglycans GAGs , proteoglycans , and glycoproteins , all of which comprise only a small fraction of the weight of the ground substance. Ground substance may be highly modified in the special forms of connective tissue. The extracellular fibers of connective tissue are traditionally classified into three types:.
Collagen is the most common protein in the body. As an essential structural element in the extracellular matrix of most connective tissues, including bone and cartilage, collagen confers toughness and tensile strength.
Scars are made of collagen. More than a dozen different varieties of collagen exist in the body, usually identified by Roman numerals. These varieties are produced by different genes, have somewhat different properties, and occur in different locations.
The most common forms are listed below. Because different types of collagen occur in different locations, various collagen defect disorders can produce different symptoms depending on which particular gene carries a mutation. The type I collagen fibers of ordinary fibrous connective tissue are colorless, so in most cases their bulk appearance is white e.
Whiteness results from scattering of light the same reason that snow is white, even though snowflakes are transparent crystalline ice. Under extraordinary circumstances of regular fiber arrangement and controlled extracellular fluid, as in the cornea of the eye , bulk collagen can be transparent.
Such pink collagen fibers are the most prominent feature of ordinary connective tissue. The ability to locate and identify connective tissue on slides is largely the ability to recognize collagen fibers. Collagen is secreted by fibroblasts as procollagen molecules, converted extracellularly into tropocollagen which self-assembles into microscopically visible fibers and grossly evident mechanical structures such as tendons.
For more on the biochemistry and related pathology of collagen, see Kierszenbaum, Histology and Cell Biology. Densely packed type I collagen fibers in dense connective tissues such as dermis and tendon provide main strength with resistance to tearing and stretching. Loosely packed collagen fibers in loose connective tissues , such as hypodermis or the submucosa of internal organs allow free movement within definite limits. Reticular fibers rete , net , made from type III collagen, provide a very delicate network hence the name supporting individual cells in certain organs lymph nodes , spleen , liver.
The collagen which reinforces cartilage, bone, basement membranes , basal lamina, and assorted other structures is not organized into microscopically visible fibers. Elastin is another fibrous protein. As the name suggests, elastin is elastic. In ordinary connective tissue, elastic fibers help restore normal shape after distortion.
Like rubber bands, elastic fibers can deteriorate with age and exposure to sun. This effect is easily demonstrated by recruiting two volunteers, one youthful and one elderly.
Pinch up a bit of skin on the back of each person's hand and then watch how quickly the skin returns to its original position when released. In elastic ligaments, dense elastic fiber concentrations convey strong elastic properties while a lesser concentration of collagen serves simply as a mechanical stop to prevent over-stretching under severe stress. In addition to its occurrence as a minor constituent in most ordinary connective tissue, elastin is also characteristic of arterial walls especially elastic arteries such as the aorta and of elastic cartilage found in ear and epiglottis.
Like everything else, connective tissues can be classified into various types. The standard classification scheme is based on composition -- that is, on the relative proportion of various cellular and extracellular components.
This scheme is not altogether satisfactory, since each component can vary along its own continuum. Within a background texture of rather universally distributed ordinary connective tissue, there also occur several very highly differentiated and localized forms of "special" connective tissue , which nevertheless share many common features structural components, cell lineages with connective tissue proper.
These special forms include bone , cartilage , lymphoid tissue spleen and lymph nodes , and blood. In routine use, the term "connective tissue" usually refers to ordinary connective tissue, while the special forms are more commonly referred to by their specific names e.
Connective tissue may be distinguished as either loose or dense , depending on the proportion of fibers. The difference between moderately loose connective tissue and moderately dense connective tissue is difficult to appreciate by microscopy, since inadvertent compression or stretching may reduce or exaggerate the space between the fibers.
This difference is better appreciated at the level of gross anatomy. If a fresh sample of loose connective were hit with a hammer, it would "squish". If a sample of really dense connective tissue, such as tendon, were hit, the hammer would bounce back. There is no sharp distinction between loose and dense connective tissue; the labels refer to the extremes of a continuum. Dense connective tissue is so named because of high density of extracellular fibers , and relatively smaller proportions of ground substance and cells.
Dense collagenous connective tissue is found wherever the tensile strength of collagen is of paramount importance. Examples include dermis the layer of the skin which yields leather , tendons and ligaments , and organ sheaths such as the sclera, or "white", of the eye.
Dense elastic connective tissue is found wherever the elasticity of elastin is of paramount importance, as in the ligamentum flavum flavum refers to the yellow color conferred by the elastin and the aorta.
Loose connective tissue has a relatively large proportion of ground substance , of cells , or of both cells and ground substance. In other words, loose connective tissue lacks the massive fibrous reinforcement that characterizes dense connective tissue.
Nevertheless, the same types of fibers are still found, although fewer and more delicate. Loose connective tissue is easily distorted, permitting tissues on either side to move freely with respect to one another. However, when loose connective tissue is distorted sufficiently, it too becomes tough and resists further deformation. The intrinsic strength of collagen is the same in both loose and dense connective tissue. To experience the mechanical quality of loose connective tissue, try the following.
See how far the two surfaces can move relative to one another. The freedom is due to the looseness of the intervening connective tissue.
The limits are set by the collagen fibers which become straightened until taut. The cells of the placenta have the same genetic material as the fetus and can therefore be tested for genetic abnormalities such as Down Syndrome.
Who is offered CVS? Most testing by CVS is offered to patients who are high risk for chromosome abnormalities. How is the test performed? The test is performed at the ultrasound clinic by an Obstetrician Gynaecologist Sonologist specialist ultrasound doctor. The skin of the lower abdominal wall is cleansed with an antiseptic alcohol based solution. The skin and underlying tissues are injected with local anaesthetic. With ultrasound control, a fine needle is then guided into the placenta and a biopsy of placenta tissue chorionic villi is taken.
The needle itself is at all times well distanced from the baby. In fact when the biopsy is taken the needle is positioned outside the pregnancy sac. When is the test performed? Ideally the test is performed between 11 weeks 2 days and 13 weeks 5 days gestation.
A moderate amount of fluid in the bladder is preferable. This can help make the uterus more accessible for the needle test. How is the placental tissue analysed? The specimen is sent to a laboratory to be processed. The tissue is placed in a culture medium and then into an incubator for several days. When there are sufficient numbers of dividing cells the specimen is removed from the incubator and the placental cells are split open with an enzyme.
The individual chromosomes are counted and analysed. Every cell should contain 23 pairs of chromosomes. As every pair is analysed, the results not only indicate the presence or absence of an extra chromosome number 21 Down Syndrome , but excludes chromosome abnormalities in the other 22 chromosome pairs.
In addition, each chromosome pair is stained with a special dye and examined under ultraviolet light. The individual bands of each chromosome are examined in great detail for subtle genetic abnormalities such as. This test excludes not only Down syndrome, but a wide variety of subtle and major chromosome abnormalities.
What should I do after the test? It is advisable for someone to take you home after the test and that you rest for the remainder of the day. This does not mean you should confine yourself to bed but rather you should just rest at home and avoid any strenuous activity including lifting any heavy weights.
Most patients experience a short duration of mild crampy period-like pains. This is most likely to occur after the local anaesthetic wears off, ie. It is safe to take paracetamol or panadol. What are the risks of the test? This is usually related to infection introduced at the time of the procedure.
Antiseptic precautions are taken to minimise this risk. Warning signs of miscarriage include strong regular period like pains with fresh red bleeding. The time when miscarriage is most likely to occur is the first hrs after the test.
Contact your doctor should this occur. Amniocentesis is a procedure in which a fine needle is passed through the maternal abdomen and uterine wall into the amniotic fluid around the fetus in order to obtain a sample of the amniotic fluid.
Cells within the amniotic fluid have the same genetic material as the fetus and can therefore be tested for genetic abnormalities such as Down syndrome. Who is offered amniocentesis? Amniocentesis is offered to patients who are high risk for chromosome abnormalities. How is it performed?
An ultrasound examination is first performed to a confirm the dates, b to assess the position of the placenta, and c assess the baby for ultrasound signs of chromosomal abnormality such as Down Syndrome.
It takes about 30 seconds to draw up the 20mL of straw coloured fluid required for analysis. When is it performed? An amniocentesis is usually performed between 15 and 18 weeks gestation.
It can, however, be performed at any time throughout the remainder of the pregnancy. What preparation is required prior to the procedure? You will need to bring a. How is the amniotic fluid analysed? The fetal cells within the amniotic fluid are harvested, cultured and treated to reveal their chromosomes.
The laboratory scientist examines the cells for an extra chromosome number 21 indicating Down syndrome and for any abnormality in the other 22 pairs of chromosomes. The individual bands of each chromosome are examined in detail for subtle genetic abnormalities such as 1 insertion of genetic material into a chromosome , 2 deletion of genetic material from a chromosome and 3 exchanging of genetic material between chromosomes translocation. What is to be expected after the test?
There is a 0. The time when miscarriage is most likely to occur is the first hours after the test. How long before I know the results? Depending on the rate of cell growth in the incubator results are available from as early as 10 up to 21 days. You will be contacted by phone with the result and a written report will also be mailed directly from the laboratory to your doctor. Are the results accurate? A chromosome result is one of the most reliable medical tests which has an accuracy in the order of Nuchal translucency is the name for the fluid behind the neck of your baby.
A collection of this fluid is taken during the 1 st Trimester scan to determine chromosomal abnormality. Normal fetuses accumulate fluid under the skin behind the head and neck between 9 and 14 weeks of pregnancy. Excess fluid has been associated with chromosome abnormalities such as Down syndrome. A simple ultrasound performed between 11 and 13 weeks can measure this fluid Nuchal Translucency. The gestational age of the fetus can be established by measuring from head to bottom — crown rump length CRL.
The NT tends to be larger in a fetus affected by a chromosome abnormality and it can be compared with what is expected for a fetus of the same size NT Normal Range. Early Pregnancy Test for Fetal Wellbeing NT-plus is a simple, straightforward and non-invasive test undertaken at weeks in pregnancy.
Chromosome abnormality All our genetic information is packed into strands of DNA called chromosomes. Normally there are 46 chromosomes in every cell. Sometimes the number or arrangement of chromosomes is abnormal — the commonest problem being Down syndrome.
Any woman who falls pregnant can have a child with a chromosome problem, but the risk increases with age. Blood tests are to be done a week prior to the ultrasound at a pathology collection centre of the patients choice. Women whose result falls into the increased risk zone will be offered further prenatal testing by CVS or amniocentesis.
The PAPP-A level tends to be lower and the BhCG level tends to be higher in pregnancies affected by Down syndrome levels seen in low and high risk patients and those with a Down syndrome affected pregnancy. What is a screening test? Different types of tests are available during your pregnancy. A screening test shows if a pregnancy is at an increased risk for Down syndrome and other chromosome abnormalities. A screening test does not give a definite answer, but it does tell us which babies have an increased risk of having Down syndrome.
The results may then help you in your decision about further diagnostic testing during pregnancy. Screening tests are simple and non invasive but do have out-of-pocket expenses attached for the ultrasound and blood test.
What is the first trimester combined screening test? The first trimester combined screening test is a two part test, which involves a blood test and an ultrasound in your first trimester of pregnancy. During the blood test, a hormone Beta human chorionic gonadotrophin and a protein pregnancy associated plasma protein A are measured. Sydney Ultrasound For Women offer the first trimester ultrasound between the 12th and 13th week of pregnancy. During this scan we measure the gestational age of the fetus by measuring from head to bottom to get the crown-rump length CRL and the nuchal translucency.
What results will I receive from this test? If the likelihood of having an abnormality is higher than a certain cut-off value, the screening test results will be classified as an increased risk. If the risk of an abnormality is lower than that cut-off value, the screening test results will be classified as low risk.
Once the screening results become available usually within 48 hours , you will be informed by one of our genetic counsellors if the result is increased. You will also be informed of the numerical chances that an abnormality is present.
What does my result mean? It is important to understand that a low risk screening result does not rule out an abnormality. Similarly, an increased risk result does not indicate that an abnormality is present.
Instead, an increased risk result may prompt you to pursue further tests, which include chorionic villous sampling CVS or amniocentesis. Why do we screen for Down syndrome? Down syndrome is the most common chromosomal cause of intellectual disability. What is Down syndrome? Cells of the body usually contain 23 pairs of chromosomes, making a total of In people with Down syndrome, all or some of the cells in their body contain 47 chromosomes, where there is an extra copy of chromosome It is this extra genetic material that results in the intellectual and physical characteristics associated with Down syndrome.
For more information about Down syndrome, please visit: What if I missed the first trimester combined screening test? If your gestation is greater than 13 weeks 6 days of pregnancy, other screening tests are available in your second trimester of pregnancy. You may wish to discuss these tests further with your referring doctor or genetic counsellor.
Where can I find out more information about these tests? Please feel free to contact one of our clinics. A pelvic ultrasound assesses the female reproductive system, including the vagina, cervix, uterus, fallopian tubes, ovaries and other pelvic structures.
It can provide helpful information for those experiencing. How is the examination performed? Transvaginal ultrasound is performed using a special transducer which is slightly thicker than a tampon. It is covered with a disposable latex sheath and lubricating gel, then gently placed into the vagina. The probe sits in the vagina throughout the examination which usually takes between minutes. Most patients find the examination much more tolerable when compared to a cervical PAP smear.
During the scan the sonographer may need to gently press on the abdomen to move bowel out of the way and bring the ovaries and other pelvic structures into view. This also enables any point of tenderness in the pelvis to be identified. Transvaginal or transabdominal ultrasound: Is there a choice? It is a Sydney Ultrasound For Women protocol to offer transvaginal assessment for all Gynaecological and early pregnancy scans.
This is because the transducer is positioned close to the pelvic structures, producing superior image quality, hence, the most detailed and accurate diagnosis. Though a SUFW protocol to offer an internal scan, patients may decline and instead be scanned transabdominally. In certain circumstances a transvaginal ultrasound examination is not possible or not advisable eg. A full bladder transabdominal ultrasound will then be performed.
What are the preparations I should take before the ultrasound examination? The transvaginal examination is best performed with an empty bladder. Upon arrival at the clinic, those booked for gynaecological or early pregnancy scans will be asked to empty their bladder. It is important that a tampon be removed prior to the examination. If you are bleeding at the time of examination the scan can still be performed. Bleeding does not affect the ability to diagnose.
Patients are draped during the examination and are given privacy when dressing. Sympathetic ganglia which lie between the sympathetic chain and the target organ [top].
The part of the nephron which collects urine from the distal convoluted tubule and passes it to the renal pelvis. The lower part of the intestines composed of the cecum , colon and rectum where moisture is extracted and digested food is then excreted as feces [top]. A group of microorgansims growing on a solid nutrient medium. Elongated cells greater in height than width; often ciliated. Intestinal wall cells [top]. Part of the biliary duct system and is formed by the junction of the right and left hepatic ducts.
When joined with the cystic duct it becomes the common bile duct. Proteins created by the liver and found in plasma which combine to form " membrane attack complexes " MAC capable of destroying target cells [top].
The shell shaped turbinate bones of the nose. The conchae form ridges that cause turbulence in the air entering the nasal cavity , which allows more air to contact the mucosa and trap particles in the air. A change so that a response that may have been associated with one stimulus , is now associated with another [top]. A reflex involving sensory inputs such as emotion, thoughts or smells processed by the cerebral cortex. Signals are then sent from the cortex to the salivary centre in the medulla where motor signals are sent to increase salivary secretion.
A cone shaped photosensitive receptor cell in the retina of the eye which functions to detect colour [top]. A process in which bacteria exchange DNA segments through a temporary structure called a pilus [top]. Tissue found between body parts and other types of tissue ; functions in protection, support and physical connection between tissues.
Composed of a cellular component and a non-living extracellular matrix. Cartilage, bone, adipose tissue [top]. Constant Regions heavy chain. A pair of polypeptide chains that are a subunit of an immunoglobulin and have a higher molecular weight.
Heavy chains serve as the binding sites for antigens. Tightening of the uterine muscles in preparation for child birth; induced and strengthened by the hormone oxytocin [top]. On opposite sides of the body; opposite meaning to ipsilateral. The left eye is contralateral to the right ear [top]. Determines the " set point " in a homeostatic control mechanism and regulates the body's response.
The control center for most body processes is the brain [top]. The transperent outer fibrous coat of the eye which covers the pupil and iris, is continuous with the sclera and admits light to the eye's interior [top]. Small follicular cells that surround the ovum in the follicle and remain attached during and after ovulation [top].
Also known as a "yellow body", it is a small body that forms in the empty follicle after the release of the mature ovum. It secretes the hormone progesterone which maintains pregnancy but becomes inactive after days if the ovum is not fertilized.
At this point menstruation occurs. The outer layer of a structure or organ [top]. A dorsal cavity encompassing the inside of the head. The cranial cavity contains the brain [top].
Cranial Nerve I Olfactory Nerve. Pair of cranial nerves which conduct nerve impulses from the mucous membranes of the nose to the brain [top]. The seventh pair of cranial nerves which supply the muscles of the face and jaw with motor nerve fibers. These nerve fibers control facial expression and the glands of the palate and taste buds in two thirds of the tongue. The eighth pair of cranial nerves which innervate the membranous labyrinth of the inner ear and consist of the vestibular nerve and the cochlear nerve [top].
The ninth pair of cranial nerves that consist of motor fibers that supply the muscles of the pharynx , soft palate, posterior tongue and parotid glands. The tenth pair of cranial nerves that consist of motor fibers which supply the muscles of the the pharynx , larynx, heart and thoracic and abdominal viscera and sensory fibers that conduct nerve impulses from these areas to the brain.
The vagus nerve functions to stimulate digestion and regulate heartbeat. A reflex response that is carried out after a stimulus is received by the brain [top].
Also known as the parasympathetic division of the peripheral nervous system because the nerves exit the central nervous system in the cranial and sacral regions of the spine.
Skin; Dry epithelial membrane covering the outer surface of the body. Consists of two layers: Epidermis and dermis [top]. A type of receptor found in the dermis and epidermis that responds to sensory stimuli. Dormant inactive form of a pathogen that is resistant to adverse conditions [top]. The duct exiting the gallbladder which joins with the hepatic duct to form the common bile duct [top]. Cellular proteins which are released by cells during an immune response and serve as communication signals [top].
Filaments that provide support and movement for the cell with the aid of ATP and motor proteins [top]. Away from the body surface; opposite meaning to superficial. The bones are deeper than the skin [top]. Also know as Pancinian corpuscles; a type of sensory receptor found in the skin that is sensitve to vibration and pressure [top].
To void feces from the rectum through the anus [top]. The act of expulsion of a child through the birth canal during child birth [top]. The branching process of a neuron that sends impulses toward the cell body [top]. Dense Connective fibrous Tissue. Tissue consisting of fibroblasts and densely packed collagen fibers with very little matrix; elastic when in ligaments. Ligaments and tendons [top]. Loss or reduction of negative membrane electrical potential [top]. Basal layer of the cutaneous membrane composed of dense connective tissue.
Areas containing large numbers of blood vessels in the dermis appear reddish [top]. The part of the colon that descends along the left of the abdomen below the spleen and ends at the sigmoid colon [top]. Cell junctions that anchor cells to one another to prevent tissues from being torn apart.
Emulsification of fats by isolating small fat droplets from each other [top]. The movement of blood cells through capillaries to surrounding body tissues. The muscular partition that separates the abdominal cavity from the thoracic cavity and assists in respiration through contraction and relaxation [top]. The shaft of a long bone. Contains the medullary cavity and bone marrow and makes up most of the length of a long bone.
The passive dilation of the heart where the chambers fill with blood. The minimum blood pressure measured during the period of the heart beat where the ventricles and atria relax to allow the chambers to fill with blood. In cell biology ; the period during which cells become specialized to form a specific cell type [top]. Responsible for the ingestion and breakdown of food to extract nutrients; Elimination of wastes. The mouth , esophagus , stomach and intestines form the major parts of the digestive system.
The stretching or enlarging of an organ or body part. Ex, dilation of the cervix during child birth [top]. A cell formed from combining two haploid gametes spermatozoa and ovum containing 46 chromasomes which will implant on the uterine wall of a female and develop into a fetus.
Contraction of a pathogen through another infected host by skin contact, sneezing, coughing, or bites from a vector such as a tick. Any type of sugar that is composed of two monosaccharides [top].
Away from the point of origin ; opposite meaning to proximal. The toes are distal to the ankles [top]. The part of the nephron located between the loop of Henle and the collecting duct. This is where urine becomes concentrated. A column of white matter in the dorsal aspect of the spinal cord where fine touch receptors are located [top]. The dorsal section of grey matter in the spinal cord where sensory receptors are contained [top]. A nodule on a dorsal root containing cell bodies of afferent neurons [top].
A tube or vessel that carries secretions from exocrine glands [top]. Cells of the pancreas that secrete bicarbonate ions to neutralize chyme in the duodenum. Any gland that secretes hormones directly into the blood stream. These glands include the pituitary, pineal, thyroid, parathyroid, adrenal , testes, ovaries and the islets of Langerhans of the pancreas [top]. The first portion of the small intestine exiting the stomach [top]. Vein channels found between the layers of dura mater in the brain which receive blood and cerebrospinal fluid [top].
A fibrous membrane that makes up the outermost covering of the brain and spinal cord [top]. The organ of hearing and equilibrium which consists of an external ear, a middle ear and a fluid filled inner ear. The ear gathers sound vibrations and conducts them to the auditory nerve which sends impulses to the brain. The outer of the three germ layers of the embryo which will form the epidermis , nervous tissue and sense organs.
An abnormal accumulation of serous fluid in body tissues. Cells , tissues or organs that carry out a body's response to a stimulus as directed by the control center. When you put your hand on a hot stove, the effectors your arm muscles retract your hand [top].
An antibody secreting cell derived from B cells [top]. A nerve that originates in the brain and transmitts impulses from the central nervous system to the peripheral nervous system [top]. Portion of the peripheral nervous system consisting of efferent nerves that send motor output information from the integration centers in the brain and spinal cord to effector organs to carry out behavioural and physiological responses.
Lymphatic vessels which carry lymph away from the lymph node. A nerve that originates in the spinal cord and transmitts impulses from the central nervous system to the peripheral nervous system [top]. A duct formed by the junction of the deferent duct and the excretory duct from the seminal vesicle that conveys semen into the prostatic urethra [top]. Consists of chondrocytes and collagen fibers with a matrix that allows the cartilage to stretch Ex. Fibers of the respiratory membrane which can stretch up to 1.
The elastic tissue that formes the outer layer of the tunica intima of blood vessels [top]. A signal that crosses a synapse that contains electrical current causing voltage changes in the postsynaptic neuron [top]. A process that occurs across the mitochondrial membrane where energy from reduction-oxidation reactions is used to produce large amounts of ATP [top]. A developing human in the womb from the time of implantation in the uterus to the eighth week of conception [top].
To convert from a solid to a liquid; in digestion, to break large lipid droplets into smaller droplets [top]. The innermost of the three layers of the walls of the heart. Ductless secretion into the blood or lymph [top]. These glands include the pituitary, pineal, thyroid, parathyroid, adrenal , testes, ovaries and the islets of Langerhans of the pancreas.
Chemical signaling system consisting of glands that secrete hormones. Hormones regulate body processes and metabolic activities. The adrenal glands are organs of the endocrine system [top]. Active transport in which materials in the extracellular fluid are engulfed by a vesicle , which then empties its contents in the intracellular fluid.
Phagocytosis and pinocytosis are both types of endocytosis. Type of endocytosis in which specialized surface receptors bind with a specific molecule type in the extracellular space. A vesicle then forms around the complexes of receptor and molecules , taking in only the molecules bound to the receptors.
Cholesterol enters cells by receptor-mediated endocytosis [top]. The inner of the three germ layers of the embryo which will form the epithelium of the digestive and respiratory tract [top]. The watery fluid within the membranous labyrinth of the inner ear [top]. A mucous membrane lining the interior of the uterus [top]. A thin layer of epithelial cells which line lymph vessels.
Also known as the intrinsic nerve plexus ; A nerve plexus of the digestive system which functions independently from the central nervous system and controls digestive function in response to stimuli inside the digestive tract. Complex proteins produced by cells that function as catalysts for biochemical reactions in the body [top].
Apical layer of the cutaneous membrane composed of stratified squamous epithelium. Keratinocytes produce keratin in the upper layers, while cells in the basal layer reproduce quickly to replace cells in the upper layers. An organ comprised of ductules that is attached posteriorly to the testes, holds sperm during maturation and is continuous with the vas deferens [top]. Abdominopelvic region superior to the umbilical region and medial to the hypochondriac regions [top]. The remnant of the epiphyseal plate where long bone growth occurred before the onset of puberty.
In adulthood, the epiphyseal plate is composed entirely of bone tissue and can no longer grow. Region between the epiphysis and diaphysis of a long bone where bone growth occurs before the end of puberty. The end head of a long bone composed of a thin layer of compact bone enclosing spongy bone ; Covered in a layer of articular cartilage that decreases friction at joints.
Continuous sheets of cells that create body linings, coverings and glands ; functions in protection, absorption , filtration and secretion. Has a free apical surface and an attached basal surface. Lining of the digestive tract [top]. Tissue composed of many cavernous blood vessels which can become engorged with blood [top]. When a previously flaccid body part containing cavernous blood vessels becomes engorged with blood and as a result becomes firm and enlarged [top].
Cells of blood that have no nucleus but contain hemoglobin which gives blood its red colour and functions to carry oxygen to the tissues.
A hormone which stimulates the creation of red blood cells and hemoglobin in the bone marrow in response to low oxygen levels in the tissues [top]. The stage of swallowing where chewed up food is passed throught the esophagus from the pharynx to the stomach [top].
The muscular, tubular structure of the alimentary canal which connects the pharynx with the stomach [top]. An amino acid that is required for growth but cannot be synthesized by cells and therefore must be supplied in the diet [top].
Hormones released by the ovaries which stimulate the development of secondary sex characteristics and development and maintenance of the reproductive system in females [top]. The spongy bone of the skull that makes up the septum of the nasal cavity and contains olfactory nerve fibers [top]. Normal and easy respiration [top].
The elimination of a substance, such as urine or sweat, from the body [top]. Relating to a secretion released through a duct externally [top]. A gland such as a sweat gland or salivary gland that releases secretions through a duct to a body part that connects to the external environment.
Active transport in which materials in the intracellular fluid are engulfed by a vesicle , which then secretes its contents into the extracellular fluid. Cells that are specialized in secretion such as glands use exocytosis frequently [top]. The exhalation of carbon dioxide out of the lungs [top].
Extension commonly occurs in the sagittal plane Ex. You straighten your leg at the knee such that your foot is lowered into a standing position.
A tubular structure running from the exterior to the middle ear. Also known as the ear canal. Outer layer of intercostal muscles; contract during inspiration and relax during passive expiration [top].
The exchange of oxygen and carbon dioxide between the lungs and external environment [top]. External Urethral Oriface opening.
The external opening of the urethra in the glans penis in males and the vestibule in females [top]. The spincter muscle located at the junction of the urethra and external urethral oriface that voluntarily relaxes so that micturition may occur.
Outside the cell ; external to the plasma membrane. The plasma is extracellular to the red blood cells in blood [top]. Extracellular interstitial fluid ECF.
Water -based solution found surrounding cells containing gases, nutrients, regulatory chemicals , salts and waste products [top]. Nerves making contact with the digestive system that originate from outside the digestive system [top]. A nerve plexus of the digestive system that works in conjunction with the central nervous system and the autonomic nervous system to control emotion and information about food. The passive movement of solutes from an area of higher concentration to an area of lower concentration through a membrane channel protein or with the aid of a transport protein.
Larger molecules that cannot move across the cell membrane by simple diffusion often require facilitated diffusion or active transport. A phase in action potential generation.
Irregular uterine muscle contractions that occur during pregnancy without dilation of the cervix [top]. Holes that allow through large molecules ; large proteins and cells cannot pass through [top].
The union of the two gametes ovum and spermatozoon to form a zygote and initiate the development of a new individual [top]. The system of structures and blood vessles which carry blood through a fetus and to and from the placenta. A fibrous protein which is created by fibrinogen during the blood clotting process and is responsible for producing an interlaced, fibrous network where cells become trapped and form a blood clot.
A plasma protein which is converted to fibrin by thrombin to facilitate blood clotting. Scar tissue ; dense connective tissue which forms underneath a healed wound [top].
The outer layer of the pericardium composed of connective tissue which anchors the heart to the surrounding body walls, protects it and prevents it from over filling [top]. Pertaining to a response to stress from the sympathetic nervous system which includes exercise and activity. Ex, A prey animal will run away from a predator through activation of the sympathetic nervous system. A fluid that has been passed through a filter.
Ex, urine after it has passed through the filtration slits in the Bowman's capsule [top]. Special type of cell transport in which a fluid the filtrate is forced across the cell membrane due to fluid pressure. The filtrate contains both solute and solvent, and only large molecules and cells are not contained in the filtrate.
Nephrons in the kidneys specialize in filtration [top]. Pores in podocytes that allow only water and small molecules to pass into the Bowman's capsule. A fringe of tissue located near the ovary that acts as a sweeper to transport the ovum from the ovary to the fallopian tube [top]. A long, hairlike appendage of some unicellular organisms that is involved in locomotion. Common in hinge and ball-and-socket joints, and opposite to extension. Flexion commonly occurs in the sagittal plane.
You bend your leg at the knee such that your foot is raised behind you [top]. Small sacs which develop on the ovary and contain an immature ovum [top]. A hormone secreted by the anterior pituitary gland which stimulates the growth of ovarian follicles containing ovum [top].
The phase of the menstrual cycle where the ovarian follicle develops [top]. An inanimate object, such as a door knob, that may carry an infectious agent [top]. An opening or passege in bone. Ex, the foramen magnum is an opening in the base of the skull [top].
A large opening at the dorsal base of the skull connecting the cranial cavity to the spinal canal [top]. Openings or passeges in bone. A fold of skin on the penis which covers the glans and is retractable [top].
Plane dividing the anterior from posterior body; the plane extends vertically through the left-right axis of the body [top]. The upper portion of the stomach where undigested food is stored [top]. A single celled microorganism which lives by decomposing the organic material on which it grows.
Mushroom shaped projections on the tongue which contain taste buds [top]. Cylindrical shape tapered at both ends. Smooth muscle cells are fusiform [top]. A small muscular sac located in the right lobe of the liver which functions to store and secrete bile into the duodenum [top]. A mass or collection of nerve cell bodies existing outside of the brain and spinal cord CNS [top]. Cell junctions that directly connect cells together for electrical and chemical communication. Protein cylinders come together in connexons to create the connection Ex.
The exchange of oxygen and carbon dioxide in the lungs during respiration [top]. Fluids and enzymes secreted by the glands of the stomach that aid in digestion including hydrochloric acid and pepsin [top]. A hormone secreted by the stomach to stimulate the secretion of gastric juices [top]. The part of the digestive system consisting of the stomach , small intestine and large intestine [top].
Stage during embryonic development when the embryo develops the primordial germ layers ectoderm , mesoderm and endoderm. The primitive gut cavity forms during gastrulation. The site of B-lymphocyte proliferation, differentiation and mutation within a lymph node. A cell or organ which produces a secretion [top]. Produces endocrine or exocrine secretions manufactured from blood components.
A small, round glandlike mass. Ex, head of the penis or head of the clitoris [top]. The volume of water filtered through the glomerulus into the Bowman's capsule per unit of time.
A network of capillaries located at the origin of the nephron where filtrate is passed from the blood to the Bowman's capsule. A hormone secreted by the pancreas that acts as an opposition to insulin in order to regulate blood glucose levels. Glucagon is a hyperglycemic hormone increases blood glucose concentration. A group of corticosteroids secreted by the adrenal cortex that function in carbohydrate, protein and fat metabolism and are used as anti-inflammatory agents [top].
Glucose is released from cells and into the bloodstream [top]. The conversion of glycogen to glucose stimulated by the hormones glucagon and epinepherine. The catabolism of carbohydrates glucose or glycogen into pyruvic and lactic acid [top]. Modifies cell products from other organelles and tags them for export.
Forms lysosomes and secretory vesicles. A hormone produced by the hypothalamus which stimulates the anterior pituitary gland to secrete leutinizing hormone and follicle stimulating hormone [top]. A sex gland that produces gametes. Ex, testis and ovaries [top]. A staining technique used to classify bacteria as either Gram positive or Gram negative. Bacteria are first stained with gentian violet and then with Gram's solution.
The bacteria are then decolourized with alcohol, washed with water and treated with Safranine. If the bacteria retain their violet colour when the process is complete they are considered Gram positive. If the bacteria show a pink colour they are considered Gram negative. Cells of the afferent arteriole which sense low blood pressure and secrete renin into the blood. Delicate pink tissue rich in capillaries that forms underneath a scab during wound healing.
Contains fibroblasts, which begin to fill the injury site with collagen fibers. Cytoplasmic particles found in some blood cells [top].
Enzymes secreted by cytotoxic T cells and natural killer cells to induce apoptosis within virus infected cells. Reddish-gray nerve tissue found in the brain and spinal cord that contains nerve cell bodies [top]. A hormone secreted by the anterior pituitary gland that functions to stimulate lactation by the mammary glands at parturition [top].
A portion of the brain which receives sensory information for taste [top]. A hairlike sensory cell contained in the epithelium of the organ of Corti in the inner ear [top]. A cell containing 23 chromasomes, such as a spermatozoa or ovum , which will fuse with another cell to form a diploid zygote. A small section of an antigen that reacts with an antibody but cannot stimulate antibody production without being bound to a carrier protein molecule.
Small pouches of the colon which give it its segmented appearance [top]. Slow, rhythmic movements of the haustra of the colon in order to mix the forming feces and recover water from it. A special sense where sound is perceived through the organ of Corti in the ear and transmitted to the brain via the auditory nerve [top]. A hollow, muscular organ located in the thoracic cavity of humans that acts as a pump to maintain blood circulation and pressure throughout the body.
The formation of blood cells [top]. The red pigment found in red blood cells which functions to carry oxygen to tissues. A branch of the celiac artery which supplies the liver with oxygenated blood [top].
A pair of ducts which carry bile from the liver to the common hepatic duct which is joined by the cystic duct from the gallbaladder to form the bile duct. Hexagonal tissue segments of the liver. A group of veins that take blood from the capillaries of the pancreas , spleen , stomach and intestine and transport it to the sinusoids of the liver [top].
A vein that transports blood from the capillaries of the pancreas , spleen , stomach and intestine and transports it to the sinusoids of the liver so it can be altered by hepatocytes before systemic circulation [top]. Any of three veins which carry blood from the liver to the inferior vena cava just below the diaphragm [top].
A liver cell [top]. A duct connecting the pancreas to the common bile duct supplying the duodenum with pancreatic juices and bile which aid in digestion.
A muscular valve which directs digestive juices into the duodenum and prevents back flow into the the pancreas and gallbladder. A plasma protein which transports cholesterol from body cells to the liver for disposal [top]. Chemical released by mast cells which causes vasodilation and increases capillary permeability [top]. The maintenance of a steady internal state despite changes in external conditions.
Humans must maintain a body temperature of approximately 37 degrees Celsius for proper homeostasis [top]. Mechanisms for maintaining survival needs within an acceptable range. If the homeostatic control mechanism for body temperature were not working properly in an individual, that individual would not be able to stay at an appropriate body temperature [top]. Chemical substances produced by endocrine glands which are secreted into the blood and transported to specific organs to stimulate their function.
Ex, estrogen , adrenaline. When a hormone binds to its individual receptor inside a cell it becomes a hormone - receptor complex which can then enter the cell's nucleus through nuclear pores and alter genetic material. Provides support for the growth of a microbe [top]. Human Chorionic Gonadotropin hCG. A hormone secreted by the placenta during early pregnancy to maintain corpus luteum function. It is found in the urine and blood of pregnant females and is often tested for to indicate pregnancy.
An immune response that is mediated by the transformation of B cells into plasma cells which produce antibodies for specific antigens and respond to them after renewed exposure. The transformation of B cells into plasma cells which produce antibodies for specific antigens and respond to them after renewed exposure. Rubbery, blue-white tissue that consists of chondrocytes and abundant collagen fibers Ex. Enzymes found in the mouth , stomach and intestines which help break down ingested materials.
The chemical breakdown of ingested materials into units small enough to be absorbed. Readily combining with or dissolving in water [top]. Repelling or unable to dissolve in water [top].
Hormones , such as glycogen, which are released to raise blood glucose levels when they drop to dangerously low levels. Abdominopelvic region lateral to the epigastric region; divided into left and right hypochondriac regions [top].
Subcutaneous tissue consisting mostly of adipose fatty tissue. Anchors the skin to underlying tissues. Abdominopelvic region inferior to the umbilical region , medial to the iliac regions and inferior to the umbilical region [top].
Hormones , such as insulin , which are released to lower blood glucose levels when they are at dangerously high levels. The point of connection of the pituitary gland to the hypothalamus. A system of blood vessels which travel between the hypothalamus and anterior pituitary gland and allows for endocrine communication between them. A section of the brain located between the thalamus and midbrain that functions to control the autonomic nervous system which regulates sleep cycles, body temperature and appetite.
The hypothalamus also releases hormones which control the hormonal secretions of the pituitary gland. Immunoglobulin G; a class of immunoglobulins that are found in circulating blood and can be passed across the placenta from the mother to the fetus.
A muscular sphincter located at the junction of the ileum and the large intestine functioning to prevent the contents of the large intestine from backing up into the small intestine. The lower portion of the small intestine located between the jejunum of the small intestine and the cecum of the large intestine [top]. Abdominopelvic region lateral to the hypogastric region ; divided into left and right iliac regions [top]. Resistance to infection by a specific pathogenic microbe.
Having a normal capacity to produce an immune response; in lymphocytes, mature lymphocytes having gained antigen receptors that give them the ability to recognize a specific antigen. Proteins found in plasma cells that act as antibodies in an immune response.
The capacity of the immune system to remember an antigen by activating memory B and T cells that will allow the immune system to respond more quickly on re- infection by the same pathogen. The attachment of an embryo to the uterine wall. The central bone of the three ossicles of the middle ear [top]. Contraction of a pathogen through fomites or contaminated food or water. Invasion and multiplication of pathogenic microbes in the body causing disease.
Towards the feet; down; opposite meaning to superior. The foot is inferior to the knee [top]. Swelling; a response to injury or pathogenic invasion that results in fluid buildup due to increased permeability of capillaries in the area [top]. To take food or drink into the body via the mouth [top]. During this phase, neurons are stimulated by neurotransmitters causing their cell membane to begin to depolarize [top]. Body defenses which defend the host from infection by responding to pathogens in a generic way; they do not adapt and they do not provide long-lasting immunity to the host.
The mass of the blastocyst where the body of the embryo is formed. The inhalation of air into the lungs [top]. Muscles used in inspiration ; external intercostal muscles and diaphragm [top].
A hormone secreted by the beta islets of the islets of Langerhans in the pancreas which functions to regulate the metabolism of glucose. Insulin is the body's only hypoglycemic hormone and lowers blood glucose levels. Ex, interpreting multiple pieces of sensory information to make a single response.
A portion of the central nervous system that is responsible for interpretation of sensory information and decision making [top]. Body coverings that protect the outside of the organism and deeper tissues. Contains receptors , sweat and oil glands. The skin is a part of the integumentary system. Small gaps between endothelilal cells that allow small molecules of any type to pass through [top].
The ventral divisions of any of eleven thoracic nerves [top]. Chemical warning signals produced by virus -infected cells that trigger anti- viral defenses in healthy cells [top].