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239 Cards in this Set
- Front
- Back
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8 common things that have a tendancy to change in animals |
1. temperature 2. pH 3. [Glucose] 4. [Oxygen] 5. [Carbon Dioxide] 6. [Na+] 7. Blood pressure 8. Heartbeat and respiratory rates |
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______ control internal body ______change with environment |
Regulators control internal body Conformers change with the environment |
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Animals that are regulators do what? |
try to maintain parameters at optimal levels through the process of homeostasis |
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Many animals are _____ for at least some parameters allowing the level to vary with the environment |
conformers |
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Extreme changes in the environment can be lethal to_____ |
conformers |
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Stressor: |
Perturbation away from set point |
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Sensor/Receptor |
Detects the error signal produced by the deviation from the set point |
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Integrator: |
Recieves information from the sensor receptor and sends compensatory signals to effectors |
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Effector: |
Produce changes to the internal environment |
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Is each component only 1 element of the homeostatic pathway? |
No some components can perform multiple roles |
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When using the homeostasis thermostat example Stressor: Sensor: Integrator: Effector: |
Stressor: change in temp Sensor: Thermostat thermometer Integrator: Thermostat Effector:Heater |
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What is the purpose of positive feedback regulation? |
To achieve something The outcome is not the same as starting point Used to drive a process to completion |
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How does positive feedback work during birth? |
Fetus puts pressure agaisnt cervix, sends signal to the brain which causes more contractions which causes more pressure on the uterus, continues until the baby is delivered |
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Which is used more often positive or negative feedback? |
Negative, used very often in homeostasis. Detects a change and encourages a change back to the set point |
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How does feedforward regulation work? |
Organisms react to stimulus by changing downstream responses to the stimulus |
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_____ can digest lactose into ____ and ____ |
E coli can digest lactose into galactose and glucose |
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What types of genes are on the lac operon? |
Genes for enzymes and other proteins eneded for lactose metabolism |
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When is the lac operon expressed? |
When lactose is present or glucose is low otherwise it is not because the enzymes and proteins are expensive to make (use lots of ATP) only want to make when absolutely necessary |
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How does the lac operon work? |
Lactose binds to the repressor on the gene which causes it to release so transcription can occur |
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What does temperatuer have a big effect on in the body? |
The rate of enzyme catalyzed and uncatalyzed reactions |
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Why is it difficult to coordinate metabolism at different temperatures? |
Because a certain change in tmperature may have a huge impact on a specific reaction and almost no impact on another |
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What is Q10 |
A measure of the sensitivity of a reaction or physiological process to a change in temperature whithin a limited range |
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Can not be extrapolated about or below the range |
Q10 |
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What is a homeotherm? |
An animal whose internal temperature stays relatively constant Environmental temperature may or may not be variable |
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What is a Poikilotherm? |
An animal whose internal temperature varies (typically along with the environment) |
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An animal whose internal temperature varies (typically along with the environment) |
Poikilotherm |
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Endotherm |
An animal that obtains heat primarily from internal sources may or MAY NOT be successful at maintaining a constant temperature |
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Ectotherm |
An animal that obtains heat primarily from external sources, may have body temperatures higher or lower than external temperature |
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Adjusting of behavior and or physiology to be better suited for the environment |
Acclimatization |
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Behavior strategies to regulate temperature are practiced by _____ for _____ |
practiced by both endotherms and ectotherms and practiced for both warming and cooling body temperatures |
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Explain the body temp of a lizard during its day |
Starts off at the temp of its burrow, when it goes above ground on a hot day it never reached the heat of the actual outside because it regulates its temperature based on action and location. It varies at a steady rate and then drops again once it goes back to its burrow |
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What are the 4 methods of heat exchange? |
Radiation Convection Conduction Evaporation |
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What is the thermal neutral zone? |
an endotherm's temperature tolerance range. Within the TNZ the basal rate of heat production is in equilibrium with the rate of heat loss to the external environment. |
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Radiation |
Heat transfers from warmer objects to cooler objects via the exchange of infrared radiation |
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When your body gets hot while standing in front of a fire this is an example of _____ |
Radiation |
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Convection |
Heat transfers to a surrounding medium such as air or water as that medium flows over a surface |
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The wind chill factor is an example of ____ |
convection |
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Conduction |
Heat transfers directly when objects of two different temperatures come into contact |
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Putting an icepack on a sprained ankle is an example of _____ |
conduction |
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Evaportion |
Heat tranfers away from a surface when water evaporates on that surface |
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Sweating is an example of ___ |
evaporation |
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_____ is a transfer of heat between both objects |
radiation |
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Who can control the amount of blood flow to the skin |
both endotherms and ectotherms |
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Heat exchange between the internal environment and external environment of the body occurs largely from |
blood flow |
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When body temp rises, blood flow to the skin _____ when body temp decreases blood flow to the skin _____ |
increaes decreases |
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How do "hot" fish retain their heat? |
through counter currents. Veins containing cold blood run counter to veins containing warm blood so warm blood heats the cold blood in the muscle area so the heat is used to keep blood warm and not released to the environment |
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_____ of our primate ancestors were probably imporant in the transition from trees to savannah |
changes in the sweat glands (more sweating =more evaporation=more cooling) |
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Within the thermoneutral zone, body temperature is regulated how? |
By passive mechanisms such as heat loss through skin |
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Below the lower critical temp... |
the animal expends energy to produce metabolic heat |
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Above upper critical temp... |
the animal must expend energy to lose heat by panting or sweating |
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Brown fat contains____ |
a large amount of blood vessels and mitochondria |
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Brown fat expresses ___ in its mitochondria which does what?? |
The protein thermogenin which promotes the leakage of protons across inner membrane of the mitochondria, generating heat but less ATP |
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The experiement which heated and cooled the hypothalumus showed what? |
When hypothalumus is heated, metabolic rate falls When hypothalumus is cooled metabolic rates increase which proves that hypothalumus IS mammalian thermostat |
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What is hibernation? |
Regulated hypothermia that lasts for days or eben weeks, with body temperature falling close to ambient temperature |
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Has to be ____ to activate _____ In order to sense signal have to have _____ |
stimuli Signal Receptor |
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Endocrine: |
Hormones that travel in blood/lymph |
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Exocrine |
travel through a duct directly to target (follow a path) |
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Paracrine- |
Travel through interstitial fluids local signal |
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Juxtacrine |
Signal remains attached to cells that produced it! |
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Autocrine |
signal to the same cell that secreted it |
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_____ structure is conserved and is _____ |
prolactin structure is conserved and expressed in many animals |
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______ function differs between animals |
Prolactins function |
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What is one of that major things that prolactin is involved in? |
The production of milk in mammals but not in birds or fish |
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What is parabiosis? |
Connecting 2 animals to test is a certain functions is determined by electrical or hormonal signal |
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How do you know during parabiosis if a function is chemical or electrical |
If it occurs in only 1 it is electrical but if it occurs in both it is hormonal because the connection of the 2 animals connects the endocrine system but NOT the nervous system |
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When does a catapillar know to turn into a butterfly? |
When the amount of juvinielle hormone levels are very low They decrease after each molt until almost none is left which means its time to turn into a butterfly |
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The stimulation to molt is electrical or hormonal? |
Hormonal |
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3 types (nature) of animal hormones |
1. Peptides 2. Steroids 3. Amines |
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What are peptide hormones? |
Proteins composed of AAs which tend to be hydrophilic, they travel well through the blood and do not cross membranes. Their receptors are on the outside of the cell |
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What are steroid hormones? |
Derived from cholesterol. They are hydrophobic. They require a carrier in the blood. their receptors are in the cytoplasm or the nucleus |
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What are amine hormones |
Derived from amino acids, they tend to be hydrophilic. Similar to peptides but not as large Also do not cross the cell membrane so receptors are on the outside of the cell |
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Where is melatonin produced? |
In the pineal gland (regulates biological rhythms) |
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2 hormones produced by the thyroid gland and their functions |
thyroxine-increases cell metabolism (essential for growth and neural development) Calcitonine- stimulates incorporation of calcium into the bone |
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What is produced by the parathyroid gland and what are its functions? |
PTH (parathyroid hormone)-stimulates the release of calcium from bone and absorbtion of calcium by gut and kidney |
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3 hormones secreted by the adrenal gland (cortex) |
1. Cortisol- mediates metabolic reponses to stress 2. Aldosterone- involved in salt and water balance 3. Sex steroids |
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What is produced by the medulla if the adrenal gland |
Epinephrine and norepinephrine which stimulate immediate fight or flight response |
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What are the 2 parts of the adrenal gland |
cortex and medulla |
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Hormone produced by the testes |
Testosterone: Development and maintenance of male sexual characteristics |
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What is produced by the ovaries |
Estrogen: development and maintenance of female sexual characteristics Progesterone: supports pregnancy |
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The thymus releases what hormone? |
Thymosin which activates the immune system T cells |
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What is produced by the pancreas? |
Insulin: which stimulates cells to take up and use glucose Glucagon: stimulates liver to release glucose s |
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Posterior pituitary gland recieved and releases _____ Which ones? |
Hypothalamic hormones Oxytocin: stimulates contraction of uterus, flow of milk and interindividual bonding Antidiuretic hormone: ADH promotes the conservation of water by the kidneys |
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Many hormones are secreted from the _____ Examples |
Anterior pituitary gland Throtropin: activated the thyroid gland Follicle stimulating hormone: stimulates maturation ovarian follicles in females and spermatogenesis in males Luteinizing hormone: Stimulates the production of sex hormones in male and female Corticotropin: Stimulates the secretion of cortisol Growth hormone: stimulates protein synthesis and growth Prolactin: stimulates milk production Melanocyte stimulating hormone Endorphins and enkephalins :pain control |
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Give the steps of a man who sees a snake in front of him |
1. The brain detects dance and signals legs to jump back 2. which signals the adrenal glands to release epinephrin into blood triggers a number of effects 3. Liver breaks down glycogen to supply glucose (fuel to blood) 4. the heart beats faster and stronger (blood pressure rises) 5. Blood vessels to the gut and skin contract shunting more blood to the muscles 6. Fat cells release fatty acids (fuel) to the blood |
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What does the ADH drug have a big effect on? |
Blood pressure, amount of water in the body effects blood pressure |
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describe a hypothalmic neuron |
cell body in hypothalamus and axon in pituitary gland |
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What is the cuddle hormone and what else does it do? |
oxytosin: important in positive feedback of mammalian birth and involved in lactation response |
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What is the role of the hypothalamus... steps |
Hypothalamus releases hormone which travel through portal vessels to the anterior petuitary gland, which releases and inhibits the release of tropic hormones |
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Which gland makes its own hormones |
Anterior petuitary Posterior secretes homones made by hypothalamus Anterior secretes hormones that are made by itself but signaled to release by hypothalamus |
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What are tropic hormones? |
Control the activity of other endocrine glands |
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External or internal conditions either promote or inhibit what? |
The release of hormone by the hypothalamus |
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After the release of hormone by the hypothalamus what happens give steps but not inhibition |
Hormone from hypothalamus stimulates the anterior petuitary to release tropic hormone which signals and endocrine gland to release hormone |
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What is the short loop negative feedback |
The tropic hormone released by the anterior petuitary inhibits the release of more hormones from the hypothalamus |
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What is the long loop negative feedback |
Hormone released from the final endocrine gland inhibits the release of tropic hormone from the endrocrine gland and also inhibits the release of more hormones from the hypothalamus |
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Beta adrenergic receptors act through: |
A G protein that stimulates adenylyl cyclasem increaseing cAMP in the cell |
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Alpha 1 receptors act through |
A G protein that inhibits adenylyl cyclase, decreasing the amount a cAMP in the cell |
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Alpha 2 receptors act through |
activates phospholipase C, increasing the production of seceral second messengers |
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_____ acts equally on _____ while _____ normally acts on _____ |
epinepherin acts equally on a and b adrenergic receptors while norepinephrin acts mostly on a |
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Example of why it is imporant to be able to turn off receptors for hormones |
Older you get you are less able to turn of receptors for cortisol, high stress levels lead to many health risks |
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Which signals can be more amplified? |
Signals with membrane receptor because they can form a cascade |
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The Y chromosome in males has ____ gene which encodes the protein ____ |
Has the SRY gene which encodes the TDF (testes determining factor) |
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If not TDF is present in an early embryo what will happen |
the embryo will become female (female is default setting) |
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How can a male be XX? |
TDF gene is translocated onto the X chromosome |
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How can a female be XY |
TDF mutation (no testes determining factor present) |
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When does the body know to start puberty? |
The production of sex hormones by the gonads in controleld by the tropic hormones (luteinizing hormone and follicle stimulating hormone which together are called the gonadotropins. The gonadotropins are stimulated to release by gonadotropin releasing hormones which come from the hypothalamus, which the hypothalamus produces very little of during younger years. Around the time of putery the hypothalamus reduces its sensitivity to negative feedback of gonadotropin releasing hormone. |
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What changes the hypothalamus sensitivity to negative feedback during puberty |
1. Leptin- controls the amount of fat in body which also tells how ready you are for childbirth 2. Bone: signals from the bone size which evolutionary if you are tall (have more bone) you are ready for a child |
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What is photoresperiodicity |
Where seasonal changes in day length cause physiological changes |
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Is more melatonin produces in the summer or winter? |
Winter because days are shorter and it is darker for longer |
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How is melatonin associated with the production of melonin |
Melatonin production changes with the season just like melonin (pigment determining) is changed. (Lighter coat in the winter to blend in with snow) |
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The more hormone you have present ______ |
The less sensative you are to the hormone |
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Normal blood glucose levels are |
80-110 mg/dl |
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Hypoglycemia is what? |
too little sugar in blood (below 72 mg/dl) |
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Hyperglycemia is what? |
too much sugar in the blood (above 125 mg/dl) |
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4 reasons blood glucose levels vary |
1. Diet 2. Metabolism 3. Excretion 4. Storage/removal from storage |
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What are symptoms of hypoglycemia |
1. brain does not have enough glucose for its metabolic needs 2. dysphoria (depression?) 3. Seizures 4. unconsciousness 5. Brain damage 6. Death |
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Common causes of hypoglycemia |
1. most common is in diabetics who have injected insulin but have not had a good meal or have injected too much insulin 2. overexertion 3. annorexia 4. lacking glucagon (which releases sugar from liver into the blood) |
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treatments for hypoglycemia |
1. Eat things full of glucose 2. Injection with glucagon 3. Surgical removal of pancrease 4. Certain medications 5. Treatment of underlying condition causing hypoglycemia |
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Prolonged _____ complications are numerous due to_____ |
hyperglycemia due to damage to blood vessels and kidneys |
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prolonged hyperglycemia can be detected how? |
with the HbA1C blood test which detects the amount of hemoglobin in the blood which has been glycated |
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Prolonged Hyperglycemia complications |
1. Neuropathy (damage to nerves in PNS) 2. Cardiovascular damage 3. Vision problems 4. Kidney problems 5. Foot and hand damage 6. Diabetes Mellitus |
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Diabetes mellitus means what? |
large amount of honey tasting urine |
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2 different types of diabetes and describe |
type 1: (juvenile; insulin dependent): pancreas does not produce insulin (usually due to autoimmune attach of beta cells of pancreas type 2: (non-juvenile although teens can get; non insulin dependent): low insulin levels, improper secretion of insulin or (most common is reduced response to insulin in the blood) |
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What are the risk factors for type 2 diabetes |
1. Heredity 2. Lack of exercise 3. obesity 4. diet (maybe related to obesity) 5. certain medications can heighten hyperglycemia |
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symptoms of diabetes |
1. thirst 2. hunger 3. excess urine 4. Fatigue 5. Blurry vision 6. erectile dysfunction 7. Dry mouth and skin 8. Weight loss 9. frequent infection 10. Wounds heal slow 11. stupor 12. coma 13. Cardiac arrhythmia 14. Ketoacidosis (excessive breakdown of fatty acids) 15. dehydration |
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treatments for type 1 diabetes |
1. Insulin 2. Replacing islet of langerhans beta cells (insulin producing cells in pancreas) |
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treatment for type 2 diabetes |
1. change diet 2. increase exercise 3. insulin 4. medication 5. bariatric surgery |
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Function of red blood cells |
Transport oxygen and carbon dioxide |
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Function of platelet cells |
Initiate blood clotting |
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Another name for white blood cells |
Leukocytes |
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Function of basophils |
Release histamine |
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Function of Eosinophils |
Kill antibody coated paracites |
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Function of Neutrophils |
Stimulate inflammation |
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Function of Mast cells |
Release histamine when damaged |
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Function of monocytes |
Develop into macrophages and dendritic cells |
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Function of macrophages |
Enguld and digest microorganisms (activate T cells) |
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Function of dendritic cells |
Present antigens to T cells |
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Function of B lymphocytes |
Differentiate to form antibody producing cells and memory cells |
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Function of T lymphocytes |
Kill virus infected cells; regulate activities of other white blood cells |
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Function of natural killer cells |
Attack and lyse virus infected or cancerous body cells |
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What are the granular cells? |
Basophils Eosinophils Neutrophils Mast cells
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What are the agranular cells? |
Monocytes Macrophages Dendritic cells B lymphocytes T lymphocytes Natural killer cells
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Which cells are produced by the lymphoid progenitor cell? |
B lymphocytes T lymphocytes Natural killer cells |
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What is the IgG antibody? |
Monomer: free in blood plasma, about 80% of circulating antibodies Most abundant antibody in primary and secondary immune response, crosses placenta and provides passive immunization in fetus |
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What is the IgM antibody? |
Pentamer: on the surface of B cells, free in blood plasma Antigen receptor on B cell membrane; first class of antibodies released by B cells during primary response
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What is a IgD antibody? |
a monomer on the surface of B cells Cell furface receptor of mature B cell Imporant in B cell activation |
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What is an IgA antibody? |
Dimer In saliva and tears and milk and other body secretions Protects mucosal surfaces; prevents the attachment of pathogens to epithelial cells |
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What is an IgE antibody? |
Monomer Secreted by plama cells in skin and tissues lining gastrointestinal and respiratory tracts Binds to mast cells and basophils to sensitize them to subsequent binding of antigen, which triggers release of histamine that contributes to inflammation and some allergic responses |
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Another word for nonspecific immune system |
innate |
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Another word for specific immune system |
Adaptive or acquired |
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Characteristics of the innate (non-specific) immune system |
-Broad defenses against multiple targets -Constitutive (always on) -Quickly engaged when needed |
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Characterisitcs of the adaptive immune system |
-Targeted at specific pathogens -Has to be activated -Slower -Memory trait, body gets more responsive with built up exposure |
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What are some of the first defenses of the innate immune system |
Barriers -skin w/ acid secretion -Mucus with antimicrobial secretions -Nasal hairs -Cilia in respiratory tubes -Acids in stomach and Vagina -Tears and saliva |
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What are some of the second defneses of the innate immune system |
-Fever -Inflammation -Coughing/sneezing -Phagocytosis by macrophages and neutrophils -Natural killer cell lysis -Complement response -Mobilize acquired defenses |
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Are natual killer cells part of the innate or specific immune system? |
innate |
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What is the first step of the inflammation response |
Damaged tissues attract mast cells which relese histamine which diffuses into vessicles |
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What does histamine do? |
Causes vessels to dialate and become leaky Complement proteins enter the infected area and attract phagocytes |
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Why does the skin become puffy during inflammation? |
Histamine triggers the leakyness of blood vessels which allow plasma and other fluid to enter the infected area |
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What happens at the end of the inflammation response? |
Histamine and complement signaling cease and phagocytes no longer are attracted to the area |
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Do the molecules in the innate immune system have receptors? |
Yes toll like receptors which and not specific and bind to many different molecules usually the flagella of bacteria uncommon DNA lipopolysaccharide |
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What does a toll like receptor do? |
Part of a protein kinase cascade that ultimately results in the transcription of at least 40 genes involved in both specific and nonspecific defense |
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How does a toll like receptor work (steps) |
1. Signal binds to toll like receptor 2. a protein kinase cascade occurs 3. The shape of the transcription factor is altered 4. transcription factor enters nucleus and binds to promoter 5. genes encoding defense proteins are transcribed |
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The adaptive immunity is divided into 2 categories |
Humoral and cellular |
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Characteristics of humoral immunity |
-Antibodies produces -free to trael through blood and lymph -produced by B lymphocytes |
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Characteristics of cellular immunity |
-Cell to cell contact (juxtacrine, paracrine, autocrine) -works through T lymphocytes (helper and cytotoxic) |
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What are the 4 key features of adaptive immunity |
1. Specificity 2. Distinguish self from nonself 3. Diversity 4. Memory |
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What is the specificity of the adaptive immune system? |
B and T lymphocytes each is specific for a specific kind of antigen epitope |
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What is the significance of being able to distinguish ones self from nonself? |
Body contains many of its own antigens so the immune system has to know not to attack own cells, does this by clonal deletion |
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What is the diversity of the immune system? |
Genetic recombination allows body to detect many different kinds of virus, bacteria, fungi, parasites and their many different strains |
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What is immunoglobin memory? |
After responding to pathogen once, body is able to respond faster and stronger to the same pathogen in the future by using memory cells |
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What did the experiemnt with the guniea pig prove |
Only serem from strain A infected pig could save other pigs. Pigs not injects or ones with B strain could not! |
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Antigen: |
Antibody generating foreign molecule found on organisms which trigger immune response |
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Epitope: |
found on antigens specific location where antibody binds to antigen |
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Antibody: |
peptides produced by B lympocytes which bind to antigens |
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___ cells contain lots of _____ |
B cells contain lots of ER and ribosomes for the production of antibody proteins |
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What is a plasma cell? |
effector B cell |
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What are the 5 different responses by antigens to antibodies? |
Agglutination Precipitation Neutrilization Opsonization Complement response |
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Agglutination: |
clump antigen bearing material
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Precipitation |
make antigen bearing material less soluable in fluid |
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Neutralization: |
binding antigen with antibody inhibits antigens function |
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Opsonization |
binding of antigen by antibody stimulates phagocytosis by macrophages |
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Complement response: |
binding of antibody to antigen stimulates the formation of pores in cells containing the antigen |
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Do both B cells make antibodies? |
NO only effector cells NOT memory cells |
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Secondary immune response involves |
Memory cells |
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What is a hybridoma? |
Monoclonial antibody produced by fusing a B cell with a tumor cell Clones are then isolated based on specific antibody desired |
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Steps of creating hybridoma |
1. mouse innoculated w/ antigen 2. Isolate B cells from spleen 3. B cells produce antibodies but do not proliferate in culture 4. Myeloma cell is fused with B cell to form hybridoma 5. Single hybridoma is isolated and grown in culture and assayed for antibody 6. Antibody producing hybridoma proliferates indefinitely in culture |
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Heavy chain has 2 regions |
Conserved and variable region |
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What does switching of the variable region involve on the heavy chain? |
Different antibody |
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What does switching of the conserved region involve on the heavy chain |
Change in class of the antibody |
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How are the number of different antibodies possible? |
Different combos for heavy chain and different combo for light chain |
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How many possible light chains vs heavy chains.. combined? |
200 light chains 10,500 heavy chains Over 2 million combos |
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How is diversity of antibodies even furthered? |
high mutation rate and sloppy joining of domains |
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Dna is lost from _____ and ____ occurs |
maturing B lymphocytes and recombination occurs |
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When B lymphocytes are maturing which of the homologs are expressed and what does this mean |
only on of the two homologs undergoes rearrangement and the other is silences which results in irreversibility of the antibody formed |
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Function of T lymphocytes |
Stimulate/ activate other T lymphocytes and B lymphocyte |
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Function of cytotoxic T cell |
promote apoptosis in specific virally infected cells |
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Function of regulator T cell |
regulate B and T lymphocytes- promoting, inhibiting destroying them |
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Antigen presenting cells: |
present antigens on their MHCII molecules to helper T lymphocytes |
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What is another name for regulatory T cells and what is their purpose? Same as other T cells Different? |
Tregs SAME -ensure immune response doesnt get out of control -have T cell receptor -become activated when bound to antigen MHC DIFFERENT -recognized self antigens -activation of tregs causes them to release interleukin 10, which blocks T cell activation and leads to apoptosis of the Tc of Th cells bound to that antigen presenting cell |
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T cell receptors are_____ Made of _____ Do what? |
Are glycoproteins Are made of 2 polypeptide chains, each with a constant and variable region have DNA rearrangment Bind to specific fragments of antigens displayed on cells |
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All characterisitcs of antigen presenting cells which include all nucleated cells |
-The antigen presented is an intracellular protein fragment -presented on a MHCI complex -is recognized by a cytotoxic T cell -The protein on the T cell is a CD8 |
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All characteristics of APC which include macrophages and B cells |
-The antigens presented are fragments from extracellular proteins -Presented on a MHCII protein -Recognized by a T helper cell -The protein on the T cell is a CD4 |
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True ACPs are what? |
cells which present their antigens on a MHCII complex |
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Activation and effector phase for the humoral immune system |
Activation: macrophages engulf and digest invaders and present them which activated T helper cells
Effector: T helper cells trigger specific B cells to replicate and produce antibodies |
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Activation and effector phase for the cellular immune system |
Activation: viral protein in cells is chopped up and displayed by MHC I protein for cytotoxic T cell. T cell replicates
Effector: Clones of cytotoxic T cell target other bad cells with the same antigen and stimulate apoptosis |
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How are T helper cells activated? |
T helper cells only bind to MHCII with specific antigen, when this happens. Interleukin I (cytokine) from macrophage activated T helper cell The T helper cells relases cytokines which stimulate itself to clone |
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Cytotoxic T cells promote___ |
apoptosis |
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What cells are activated by T helper cells? |
Generally B lympocytes, singals them to produce antibodies Also activates Tc cells to target the same virus that has already made its way into other cells |
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____ cells undergo _____ during maturation which does what? |
T cells undergo thymic education during maturation Which promotes positive selection for T cells which interact with proper MHC proteins and promote negative selection against T cells which bind to self antigens |
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Why do many auto immune diseases increase in frequency with age? |
the thymus is the first organ to begin to decay |
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____ connects humoral and cellular immune system |
T helper cells |
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HIV is what type of virus. This means what? |
It has an RNA genome which is converted into DNA and then inserted into hosts genome and replicated |
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Description of the appearance of HIV |
surrounded in bud (envelope) from the cell membrane. Have glycoproteins |
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How does the replication of HIV work? |
RNA to DNA which inserts into genome and is replicated and transcribed and mRNA is the genome of the new HIV virus |
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CD4 and CD8 are also called____ |
also called Co-Receptors |
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Why is there so much mutation in HIV |
because the reverse transcriptase has no mismatch repair |
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Why a couple both infected with HIV still practive safe sex |
Dont want swapping and 2 different strains of HIV or recombination (could result in strain that is not treated by medicine) |
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How does the HIV virus so easily infect T helper cells and other immune cells? |
The glycoprotein on the outside of their membrane binds specifically to the CD4 co-receptor molecule on Helper T cells, macrophages and dendritic cells. Which results in fusion of the viral membrane with the immune cell membrane |
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Describe the process from initially contracting HIV to about 15 years later |
Initially the amount of HIV virus in the bloodstream increases quickly and the infected patient experience some cold like symptoms. Antibodies are then secreted and the viral load decreases. A long asymptomatic period is usually experienced (5-10) years until enough T helper cells are killed off and HIV concentration begins to rise again |
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Ways the HIV virus is able to evade the immune system |
Antigenic variation- virus alters its surface proteins inorder to evade immune response
Latency of proviral state- lay dormant and randomly produce new virus |
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The HIV virus is not only able to avoid immune system but _____ |
over time able to detroy it |
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During the asymptomatic period where are HIV viruses replicating? |
in the helper T cells |
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What is happening to the helper T lymphocytes during the asymptomatic period? |
They are killed directly by the HIV virus being inside them and also killed by cytotoxic T cells which can detect that they are infected |
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_____ are slowly destroyed by the HIV virus during the asymptomatic period |
The lymphnodes |
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What is the HIV virus doing during the asymptomatic period? |
Continues to replicate and generate new strains through mutation |
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What is the symptomatic period of HIV? |
This is when the person is considered to have overt AIDS Begins when the concentration of helper T cells drops too low (CD4 count below 200). Cellular immunity collappses because cytotoxic T cells cant be stimulated by helper T cells and the AIDS patient usually dies due to other infections that it is unable to fight off. |
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Where is the set point of HIV infection and what does this tell us? |
This is when the concentration of the HIV virus in the body reaches rock bottom and begins to rise again. The amount of time that it took to get to this point usually is an indicator as to how fast the disease is progressing. |
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The B cell binds to where on the antigen? |
the EPITOPE |
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There are billions of B cell antibody combos why are not all used |
Some of these code for self antigens which would be BAD |
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First line of nonspecific defense vs second line |
First line keeps pathogens out of body. Second line gets pathogens out of body that have made it past the first line |
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B lymphocyte produced_____ T lymphocytes produced_____ |
B in bone marrow T in bone marrow but mature in thymus |
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Hurmoral immunity deals with _____ Cellular immunity deals with |
Humoral____ pathogens that are in interstitial fluid Cellular deals with pathogens that have made their way into cells |
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Helper T binds to which MHC? |
MHCII |
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Why are T helper cells needed. Why cant B cell just divide when it binds to antigen |
Just incase B cell has mutation which binds to self antigen, it will not be signaled to divide unless T helper cell also signals division |
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Cytotoxic T cells bind to which protein? |
MHCI |
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CD4 wants to bind to ___ CD8 wants to bind to ___ |
CD4 wants MHC II CD8 wants MHC I |
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Why are co-receptors there? |
Because if T helper cell bound to MHC I and thought it was MHC II it would signal the cell to divide which would be BAD because this is an infected cell! |
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Nail pierces skin what happens? |
1st cell releases chemokines (SOMETHING BAD HAPPENED Chemokines activate mast cells which release histamine which causes inflammation of capilaries which allows them to become permeable to white blood cells and fluid which enter into infected area Complement proteins also go into area and help kill bad cells |
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Why do you take an antihistamine with a runny nose? |
Histamine causes excess fluid which results in runny nose. that is why antihistamine will reduce these fluid build up symptoms |
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How do phagocytes (part of nonspecific immune system) know what is bad and what is good to kill? |
They still have receptors they are just not as specific as the onces involved in specific immune system (called tole like receptors) |
