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Physiology
Exam # 2
122
Physiology
Undergraduate 4
05/13/2013

Additional Physiology Flashcards

 


 

Cards

Term
Define motor unit!  What is motor unit recruitment?
Definition

 A motor unit is a motor neuron and all the muscle fibers it innervates. Motor unit recruitment is increasing the number of muscle fibers that contract within a muscle.

Term
What is tetanus?
Definition
Sustained muscle contraction of maximal strength
Term
What protein makes up thick filaments?
Definition
Myosin
Term
What proteins make up the thin filaments?  What are their functions?
Definition

 

Actin- binds to myosin to contract muscle,

 troponin- calcium binds to it to move tropomyosin,

tropomyosin- blocks actin until it is moved by troponin.

 

Term
Where is myosin ATPase located?  What is its function?
Definition
Myosin ATPase is located on the myosin head. Its function is to hydrolyze ATP into ADP and Pi so that another contraction can occur
Term
Where would you find dihydropyridine receptors?
Definition
Dihydropyridine receptors can be found in the SR
Term
What is the function of the ryanodine receptors/channel?
Definition

 Ryanodine channels release calcium once it has been opened by the electrical signal.

Term
What is creatine kinase?  What is creatine phosphate?
Definition

 

Creatine kinase is the enzyme that helps our body to store ADP and creatine phosphate because we cannot store a lot of ATP. Creatine phosphate is what our body is able to store while ATP is not needed for use.

 

Term
What is the difference between neuromuscular fatigue & psychological fatigue?
Definition

  Neuromuscular fatigue occurs when AcH synthesis cannot keep up with demand, and psychological fatigue occurs when motor neuron activity decreases below desired state

Term
What is the difference between hypertrophy & hyperplasia?
Definition

Hypertrophy is when there is an increase in muscle fiber diameter due to an increase in myosin and actin synthesis.

Hyperplasia occurs when cells increase in size and then split lengthwise so there is an increase in the number of cells.

Term
What lines mark the end of the sarcomere?
Definition
Z lines
Term
What is a sarcomere?
Definition
The functional (contractile) unit of muscle.
Term
What is the neurotransmitter used at the neuromuscular junction?
Definition
Acetylcholine
Term
Why is ATP needed for relaxation?
Definition
ATP binds to the myosin head allowing it to release from actin, and if calcium is pumped back into the lateral sacs, the muscle can relax
Term
What is the function of the sarcoplasmic reticulum?
Definition

 Release calcium once the AP has traveled down the T-tubules

Term
What is the function of magnesium in cross-bridge cycling?
Definition

Magnesium helps to hydrolyze the ATP so myosin ATPase can break it down

Term
What is rigor mortis?
Definition
Rigor mortis occurs once people die. There is an influx of calcium to allow muscle contraction to occur, but ATP is no longer being generated so the actin and myosin are not able to release from each other, so the muscles are locked in place until they start to degrade
Term
What is the function of the calcium ATPase pump?
Definition

 

Calcium ATPase pumps calcium back into its lateral sacs so that muscle relaxation can occur.

 

Term
Define latent period
Definition
The beginning of the stimulus to the beginning of contraction.
Term
How can muscle contractions be varied in strength?
Definition

 Muscle contractions can vary in strength by changing the number of muscle fibers that contract within a muscle, and the tension developed by each contracting fiber.

Term
How can tension be developed in individual fibers?
Definition

 

 Motor units are recruited and more muscle fibers are stimulated to contract.

 

Term
Describe twitch summation
Definition

Similar to temporal summation in that as long as another AP is generated before the previous AP fully resets, and then the two will summate and create a stronger AP resulting in more tension developed in the muscle fiber.

Term
What does it mean by optimal muscle length?
Definition

There is the maximum amount of cross bridges that can be formed by the myosin and actin

Term
Why is tension development less in a shortened or lengthened sarcomere?
Definition

 

In a shortened sarcomere, there is not the optimum number of cross bridges that can be formed, the calcium is not able to be released from the SR, and calcium is not able to bind to troponin because it is being blocked. In a lengthened sarcomere, there is also less than the optimum number of cross bridges that can be formed.

 

Term
Define isotonic and isometric contractions.
Definition

 Isotonic- same tension, but muscle length changes,

 isometric- same muscle length, tension changes

Term
Why does lactic acid induce fatigue?
Definition

 Lactic acid changes of the pH of the muscle, causing fatigue in the area.

Term
What are the 3 types of skeletal muscle fibers?
Definition

 

 Slow oxidative type 1 fibers, fast oxidative Type IIA fibers, fast glycolytic type IIB fibers

 

Term
What is the function of myoglobin?
Definition

Myoglobin increases the rate of oxygen transfer from the blood and imparts a red color to the fibers

Term
What is disuse atrophy? What is denervation atrophy?
Definition
Disuse atrophy-decrease in muscle mass due to inactivity, denervation atrophy- nerve supply to muscle is lost
Term
How can the ATP synthesizing capacity of muscle be changed?
Definition
ATP synthesizing capacity of muscle can be changed with increase mitochondria content and increase vascularization to the fibers
Term
What is the function of muscle spindles?
Definition

 They monitor changes in muscle length and tension to regulate it and keep the muscle at optimum length

 

Term
Describe the internal architecture of a smooth muscle cell.
Definition
Dense bodies are anchored throughout the cell and are attached to the cell membrane by intermediate filaments, actin are anchored to dense bodies, myosin interacts with actin, no t-tubules, poorly developed sarcoplasmic reticulum
Term
Describe how a smooth muscle cell undergoes contraction.
Definition

Increased calcium concentrations, calcium bind to calmodulin, and activate myosin kinase. Myosin kinase phosphorylates myosin allowing it to bind to actin. The thick and thin filaments slide across each other, and the cell collapses or shrinks due to a pulling effect on the dense bodies and the intermediate filaments.

Term
What is the difference between pacemaker activity & a slow wave potential?
Definition

Pacemaker activity occurs when the membrane potential gradually depolarizes due to shifts in passive ionic fluxes, resulting in an AP, Slow Wave potentials occurs when there are alternating depolarizations & repolarizations of the membrane, resulting in an AP if the depolarization is significant enough.

Term
What are the anatomical differences between skeletal, smooth, & cardiac muscle?
Definition

 Skeletal- striated, Smooth- unstriated, Cardiac- striated with intercalated disks.

Term
What are varicosities?
Definition

Varicosities are holes at the end of a motor neuron in which the neurotransmitter is released from. Does not directly innervate receptor but is close enough for neurotransmitter to reach receptor.

 

Term
What are the 3 main plasma proteins & what are their functions?
Definition

Albumins- transports molecules, but makes biggest contribution to colloid osmotic pressure, Globulins- alpha & beta for clotting and gamma for antibodies, Fibrin- for platelet clotting

Term
What is a hematocrit?
Definition
The concentration of erythrocytes that occupy the total blood volume
Term
Do erythrocytes contain a nucleus?
Definition
NO!
Term
What is the function of hemoglobin?  Describe its structure
Definition

  hemoglobin is the molecule that carries oxygen in the blood. It is composed of 4 globin molecules and 4 iron containing heme groups which bind to oxygen

Term
How do erythrocytes generate ATP?
Definition
Through anaerobic glycolysis because they do not have mitochondria
Term
What is the function of carbonic anhydrase?
Definition
Carbonic anhydrase transports carbon dioxide.
Term
What hormone controls erythropoiesis?
Definition
Erythropoietin secreted by the kidneys
Term
Define anemia.
Definition
A decrease in the body’s ability to transport oxygen to the body
Term
What are the differences between nutritional anemia, renal anemia, & hemolytic anemias?
Definition

Nutritional- iron deficiency which occurs with low hemoglobin synthesis and folic acid which are aberrations in DNA synthesis leading to fewer RBCs dividing and maturing, Renal- Kidney disease which causes low

production of erythropoietin, Hemolytic- excessive rupturing of circulating erythrocytes such as sickle cell anemia and malaria

Term
Define polycythemia
Definition
Excessive number of circulating erythrocytes
Term
What is the difference between primary, secondary, & relative polycythemia?
Definition

Primary- tumor like condition in the bone marrow increasing the viscosity of the blood which increases blood pressure,

Secondary- increase in erythropoietin secretions due to environmental conditions such as high altitude, Relative- dehydration in which RBC count is not elevated but hematocrit is high

Term
What are the five types of leukocytes?
Definition
Neutrophils, basophils, eosinophils, monocytes, leukocytes
Term
What is the difference between a granular & an agranular leukocyte?
Definition

  Granular contains granules, and agranular does not contain granules

Term
What hormone regulates platelet production?
Definition

 

Thrombopoetin is the hormone that regulates platelet production

 

Term
Do platelets possess actin & myosin?  What is the function of the actin & myosin?
Definition

Platelets possess actin and myosin so they can contract during the platelet plug formation to pack more platelets closer together and make the plug stronger.

Term
What is vascular spasming?
Definition
Vascular spasming occurs when the cut blood vessel constricts to reduce blood flow and the endothelial surfaces adhere as the vessel constricts.
Term
Describe platelet plug formation.  Include all the molecules involved in the process.
Definition
Platelets attach to the exposed collagen in the damaged vessel. This stimulates the platelets to secrete thromboxane A2 and ADP to induce stickiness of the platelets, and the platelets layer at the damaged site (Normal endothelium secretes prostacyclin which inhibits aggregations). Platelets then seal the wound but also contract to compact more platelets to strengthen the plug. TXA2, serotonin, and epinephrine secretions also secreted by the platelet plug induce vasoconstriction. Other released chemicals also induce clotting.
Term
What is the difference between the intrinsic vs. extrinsic blood clotting pathways?  Where do they meet?
Definition
Intrinsic and extrinsic differ in the beginning, but meet at the common pathway.
Term
Describe blood clotting with details.
Definition

Intrinsic- Hageman’s factor is activated when it meets the exposed collagen of the damaged blood vessel. This activates factor X, which causes prothrombin à thrombin. Thrombin then catalyzes fibrinogen à fibrin and activates factor XIII to seal fibrin net.

 

Extrinsic- Tissue thromboplastin is released by the damaged tissue. This activates factor X, which causes prothrombin à thrombin. Thrombin catalyzes fibrinogen à and activates factor XIII to seal fibrin net.

 

Term
Describe clot removal
Definition
Plasminogen à plasmin by many factors including Hageman’s. This activation occurs at the same time as clotting occurs. The plasmin gets trapped within the clot, and the plasmin slowly breaks down the fibrin network from in to out.
Term
What is the difference between a thrombus & an embolus?
Definition
Thrombus- a clot attached to a blood vessel, Embolus- free flowing clot
Term
80% of all hemophiliacs lack the ability to synthesize?
Definition
Factor VIII
Term
What are the autorythmic portions of the heart?
Definition

SA node, AV node, Bundle of His, Left and Right Bundle Branches, Purkinje Fibers

Term
Describe the ionic fluxes associated with an autorythmic cells pacemaker/action potential?
Definition

Slow depolarization phase 1- decrease Pk increase to Pna (funny channels), slow depol phase 2- decrease Pna and increase Pca (T-type calcium channels), fast depol- increase Pca (L-type calcium channels), repolarization- decrease Pca increase Pk

Term
What is an ectopic foci?
Definition

Another pacemaker creates a higher AP than the SA node causing an extrasystole (premature heartbeat)

Term
What is complete heart block?
Definition
SA node signal cannot reach ventricles, ventricles follow their own rate due to Bundle of His and Purkinje cells, disconnect between atria and ventricles
Term
Describe the ionic fluxes associated with cardiac contractile cells’ action potential?
Definition

 

Sharp depolarization due to increase Pna, Plateau phase due to increase Pca and decrease Pna & Pk, repolarization due to increase Pk & decrease Pca

 

Term
Why is the cardiac contractile cell’s AP the same duration as the muscle contraction?
Definition
This is because of the refractory period and the plateau phase, not allowing Na+ channels to reset preventing tetanus
Term
What are the waves associated with an ECG?
Definition
P wave, QRS complex and T wave
Term
What is tachycardia? What is bradycardia?
Definition

Tachycardia- increased rate > 100bpm, Bradycardia- decreased rate < 60 bpm

Term
Why do the ventricles have to go through both an isovolumetric contraction & relaxation phase?
Definition
Ventricles go through an isovolumetric contraction to build up enough pressure to eject the blood out, and isovolumetric relaxation phase to lower the pressure so that the ventricles can get ready to fill up with blood again
Term
What valves are responsible for the 1st & 2nd heart sounds?
Definition

1st heart sound is the AV valve and

2nd heart sound is the aortic valve

Term
What is the difference between a stenotic valve & an insufficient valve?
Definition

 Stenotic- does not open completely, Insufficient- does not close completely

Term
What is difference in both structure & function of a conducting artery vs. a distributing artery?
Definition

Large conducting arteries aid in pumping blood (thin walled, more elastic fibers, less smooth muscle) muscular distributing arteries determine where blood is needed and controls overall blood pressure (thick walled, more smooth muscle, less elastic fibers)

Term
What is vasocontriction?  What is vasodilation?
Definition
Vasoconstriction decrease in radius increasing blood pressure, vasodilation increase in radius decrease blood pressure.
Term
What are the 3 types of true capillaries?
Definition
Continuous, sinusoidal, fenestrated
Term
Describe the formation of lymph
Definition

 Anchoring filaments attach lymphatic endothelial cells to surrounding tissue. When swelling occurs in the interstitial tissue due to water entering from the blood capillaries, the anchoring filaments are moved due to their attachment to the cells. This movement pulls on the lymphatic endothelial cells, which separates them. Fluid then flows into the lymphatic vessels down a pressure gradient. When fluid is drained, the anchoring filaments move back to original position, and the spaces between endothelial cells close.

Term
What is edema? What can cause it?  
Definition

 Edema is the swelling of blood vessels due to the invasion of pathogens. It occurs when too much interstitial fluid accumulates. Potential causes: reduced concentration of plasma proteins which reduce water re-absorption, increased permeability of capillary walls allowing more plasma proteins and water to move into the tissue, increased venous pressure which increases capillary pressure and reducing water reabsorption, blockage of lymph vessels in which fluid cannot return to the blood.

Term
What is cardiac output?  What are its two determinants?
Definition
Cardiac output is the amount of blood pumped out by the ventricles per minute, determined by heart rate and stroke volume
Term
Describe in detail how the parasympathetic branch of ANS modulates heart rate?  Does it modulate stroke volume?
Definition

 The muscarinic cholinergic receptor and G protein activation, AcH increases SA node permeability to K+ closing the T-type calcium channels and funny sodium channels, hyperpolarizing it and taking it longer to reach threshold. AcH hyperpolarizes the AV node, and decreases atrial contractile strength by shortening plateau phase. Does not modulate stroke volume because it only innervates the atria.

Term
Describe in detail how the sympathetic branch of ANS modulates heart rate & stroke volume?
Definition

Beta I adrenergic receptors & cAMP 2nd messenger system, NE increases both sodium funny and T-type calcium channel opening which increases the rate of spontaneous depol. NE reduces AV nodal delay by enhancing the slow, inward (T-type) Calcium. Beta I adrenergic NE increases both atria & ventricular contraction strength by increasing Ca influx through L-Type calcium channels, Ca release from SR increasing myosin ATPase activity & increasing Ca re-uptake to relax faster

Term
What is Frank-Starling Law of the Heart?
Definition
The heart will pump all the blood that is returned to it
Term
What is heart failure?
Definition

 Inability of the cardiac output to keep up with the body’s demands for supplies & removal of wastes.

Term
What is the difference between backward failure & forward failure?
Definition
Backward- blood dams up in the venous system; Forward- blood cannot be adequately supplied to the tissues.
Term
What is the role of adenosine in coronary circulation?
Definition

Adenosine is the control for linking coronary blood flow to the oxygen requirement of the heart

Term
What is the difference between systolic & diastolic pressure?
Definition

 Systolic- pressure developed by contracting the heart, Diastolic- minimum pressure within the arteries as the blood is draining off into the remainder of the vessels during diastole

Term
What is pulse pressure?
Definition
The pulse that is felt in the artery lying close to the surface of the skin due to the difference between the systolic and diastolic pressure
Term
What is the formula for calculating MAP?  What are the two determinants of MAP?
Definition
MAP = diastolic pressure + (1/3) pulse pressure. Cardiac output and total peripheral resistance determines MAP.
Term
What local factors would cause vasoconstriction of arterioles?
Definition
An increase in O2 of local metabolic control, causing an increase in the extrinsic part of the sympathetic activity and epinephrine causing the sodium funny channels and T type calcium channels to open causing an increase in extrinsic vasoconstriction control, which causes vasoconstriction in the arterioles
Term
What local factors would cause vasodilation of arterioles?
Definition
A decrease in the O2 of local metabolic control, and a decrease in the extrinsic portion of sympathetic activity and epinephrine coming in causing a decrease in extrinsic vasoconstriction control, which causes the arteriolar radius to increase.
Term
Does nitric oxide induce vasoconstriction or vasodilation?  How about endothelin?
Definition
Nitric oxide induces relaxation of smooth muscle and vasodilation.  Endothelin induces vasoconstriction.
Term
What is reactive hyperemia?
Definition
Reactive hyperemia occurs when the blood vessels dilate due to obstruction. When the blood flow to a region is completely blocked, arterioles in that region dilate due to myogenic relaxation due to diminished stretch with no blood flow and changes in local chemical composition. Then when the occlusion is removed, blood flow through that region is transiently higher.
Term
Why is pressure autoregulation a bad way to control blood pressure?
Definition

 Pressure autoregulation is a bad way to control blood pressure because although it dilates the blood vessels to get more blood to area that needs it, it does not take into account actual blood pressure. It actually only really regulates blood flow. So when MAP decreases, blood flow decreases, arterioles dilate to restore flow, but this causes MAP to also further reduce which is bad for the body, and the opposite is also true.

Term
What is bulk flow?
Definition

 Bulk flow is used to determine volume between the vascular and interstitial fluid compartments when moving materials across the capillary wall. It is the ultrafiltration of plasma from the vascular side to the interstitial tissue side due to capillary pressure, which is protein free plasma. It causes reabsorption when inward pressure is greater.

Term
What is colloid osmotic pressure?
Definition
The pressure of plasma proteins in the blood vessels
Term
What determines the amount of blood in the veins vs. the amount returned to the heart?
Definition

Venous capacity which is the volume of blood the veins can accommodate, and venous return which is the volume of blood entering each atrium per minute

Term
What determines venous capacity?
Definition

 The distensibility of the veins and any externally applied pressure such as skeletal muscle contraction which decreases capacity and increases venous pressure

Term
How can distensibility of the veins be changed? How is this different from arterioles?
Definition

  Distensibility can be changed by sympathetic activity, which induces vasoconstriction decreasing the volume and capacity of the veins. This then increases the blood flow back to the heart.

Term
What factors modulate venous return?
Definition
Cardiac contraction pressure gradient, sympathetic activity, skeletal muscle activity increases flow, venous valves serve as one way stops and ensures venous unidirectional flow, respiratory activity which lowers pressure in the chest vs. the extremities, and cardiac suction which is the contraction of the ventricles creating a favorable pressure gradient that moves blood into the atria.
Term
Describe baroreceptor reflex for maintaining blood pressure.
Definition
The baroreceptor reflex is the most important mechanism for short-term regulation. It is a sensory receptor sensitive to stretch. It is the adjustment of cardiac output and total peripheral resistance. Key baroreceptors are located in the carotid sinus and aortic arch. When pressure increases, the receptor potential increases, increasing AP firing in the afferent neuron, and is the reverse for a decrease in pressure. The impulses are then integrated in the cardiovascular control center of the medulla, and generate the appropriate sympathetic and parasympathetic responses
Term
What is hypertension?  What is the difference between primary & secondary hypertension?
Definition

 Hypertension occurs when the blood pressure is above 140/90 mmHg. Primary hypertension occurs more often and has unknown causes, and secondary hypertension occurs less often and is caused by a known or primary pathological problem.

Term
What is the difference between cardiovascular, renal, endocrine, & neurogenic hypertension?
Definition

Cardiovascular- hypertension due to atherosclerosis,

Renal- hypertension caused by an increase in overall blood volume due to reduced blood flow to the kidneys (atherosclerosis) and increased salt retention,Endocrine- hypertension caused by Pheochromocytoma which is adrenal medulla tumor caused by excess epinephrine and norepinephrine and Conn’s syndrome which is an increase in aldosterone secretion by the adrenal cortex inducing salt retention, Neurogenic- hypertension due to a defect in nervous control receptors and center, and due to a reduction in blood flow to the brain.

Term
What is hypotension?  What is orthostatic hypotension?
Definition

  Hypotension is when blood pressure drops below 100/60 mmHg. Orthostatic hypotension occurs when there is a shift from lying down to coming to an upright position. This is because the reflexes are inadequate, blood pools in the veins, and pressure drops. Baroreceptor reflexes kick in.

Term
What is circulatory shock?
Definition

 Circulatory shock occurs when tissues cannot be maintained due to low blood pressure.

Term
What are the 4 types of circulatory shock?
Definition

Hypovolemic shock- fall in blood volume; hemorrhaging; vomiting, Cardiogenic shock- weakened heart making it unable to pump blood, Vasogenic shock- widespread vasodilation due to substances (septic- massive infection; vasodilator substances released by bacteria and anaphylactic- allergic reaction; histamine is released), Neurogenic shock- loss of sympathetic vascular tone resulting in vasodilation and is induced by pain.

 

Term
What is a pathogen?
Definition
A disease causing molecule
Term
What are the two types of lymphocytes?
Definition
B-cells and T-cells
Term
What are the non-specific immune response mechanisms?
Definition

 Inflammation, Interferon, Natural killer cells, and the Complement System

Term
Describe how the interferon pathway works
Definition
Virus enters the first cell, and the infected cell released interferons to local cells. The interferon binds with the receptors on the uninfected cell and initiate production of inactive enzymes capable of breaking down the virus. Then once the virus enters these cells, the enzymes are activated and the viral RNA is destroyed.
Term
Define margination, diapedesis, & chemotaxis.
Definition

  Margination- stickiness of the leukocytes to the inner endothelial lining of capillaries of the affected tissue. Caused by cell adhesion molecules, which protrude through the endothelial lining, Diapedesis- Amoeboid movement of the leukocytes through capillary pores, Chemotaxis- leukocytes are drawn toward their targets by chemotaxins, which are secreted, from the cells of the damaged area.

Term
What are the functions of kinins? endogenous pyrogens? lactoferrin? opsonins? complement system proteins?
Definition
Kinins- enhance inflammatory response, stimulate the complement system & act as chemotaxins, Endogenous pyrogens- induces a fever, lactoferrin- binds to iron making iron unavailable for use by bacteria, opsonins- chemicals that adhere to the pathogen making them easier to be identified and phagocytized, complement system proteins- a group of inactive plasma proteins that when activated attack & destroy the plasma membranes of foreign cells
Term
What is the difference between humoral & cell-mediated immunity?
Definition

Humoral immunity occurs when B cells are differentiated into plasma cells to secrete antibodies and cell-mediated immunity is when T cells differentiate into cytotoxic t cells to directly destroy the pathogen.

Term
Describe the structure of an antibody?
Definition

  Antibody is composed of two light chains and two heavy chains in the shape of a Y, with the light chains on the outside and the heavy chains on the inside. The tips of the Y are where the antigen binding fragments are (Fab) and the tail of the Y is where it interacts with the immune cells (Fc).

Term
Describe the five mechanisms by which antibodies destroy pathogens.
Definition

Agglutination- antibodies cause the pathogens to clump together preventing proper function, Neutralization- antibodies bind with the pathogen preventing function, Activation of complement system- activation of complement system proteins which attack cell membrane of pathogen, Opsonization- antibody tails bind with phagocytes to enhance phagocytosis, Stimulation of Killer cells- abnormal body cells bound by antibodies recognized by natural killer cells and instantly lyses it

Term
What is the difference between active & passive immunity?
Definition
Active- production of antibodies in response to exposure to an antigen, Passive- transfer of antibodies actively formed by another person or animal
Term
How do cytotoxic T-cells destroy an infected self-cell?
Definition

Cytotoxic T cells secrete perforin to the infected cell causing it lyse and leak

Term
What are the different types of T-cells?  What are their functions?
Definition

Cytotoxic T cells- destroy infected “self” cells via secretion of perforin, Helper T cells- secretes B cell growth factor & T cell growth factor, secretes chemotaxins, macrophage-migration inhibition factor to keep phagocytes from migrating out of the infected area, Suppressor T cells- inhibit the immune response and are slow to develop, Memory T cells- provide rapid mobilization of the immune response if the system is subsequently exposed to the same antigen.

Term
What is perforin?
Definition
Perforin creates holes in the target cell’s membranes causing it to lyse and leak.
Term
Where would you find MHC class I proteins?  MHC class II proteins?
Definition

 MHC class I is on all body cells except white blood cells, MHC class II is only on white blood cells

Term
What is the difference between TH1 & TH2 with regards to stimulating an immune response?
Definition

 TH1 stimulates cell mediated response, TH2 stimulates humoral response

Term
What interleukins stimulate the development of TH1 & TH2 respectively?
Definition

   Interleukin 12 stimulates TH1 and Interleukin 4 stimulates TH2

Term
Outline how the specific immune response is initiated
Definition
The virus infects a cell and is phagocytized by the macrophage. The lysosome lyses the pathogen and breaks it down to be presented on the MHC II receptor. The macrophage then presents the pathogen to the helper T cell via the antigen-MHC complex. The original Helper T cell then secretes interleukin 4 to induce TH2 differentiation for humoral response and interleukin 12 to drive TH1 differentiation for cell-mediated response. TH2 then secretes B cell growth factor to immature B cells. The immature B cells then differentiate into Plasma cells and memory B cells. Plasma cells then secrete antibodies to recognize and bind to the pathogen so that it can be destroyed. IgM is secreted as a B cell surface receptor for antigen attachment, and IgE is secreted as an allergic response. IgG is used to recognize pathogens in case they infect the system again. Both IgG and IgM are used together to target bacteria and some viruses. Memory B and T cells are responsible for adaptive immunity and secondary response so that the duration of being sick is significantly cut short. TH1 secretes T cell growth factor to immature T cells. The immature T cells then differentiate into cytotoxic T cells and some memory T cells. Then when the cytotoxic T cell recognizes an infected cell via the MHC I receptor, it secretes perforin onto the cell causing it to lyse and leak, and the pathogen is destroyed.
Term
What is myasthenia gravis?
Definition

Antibodies are produced to attack the acetylcholine receptors on skeletal muscle

Term
What is severe combined immunodeficiency disease?
Definition
This occurs when there is reduced resistance to foreign invaders because both B cells and T cells are lacking.
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