TPR - Ch 9 - Circulatory, lymphatic, and immune system Flashcards
1
Q
Functions of the cardiovascular (CV) system?
A
1) Distribute nutrients, O2 (from lungs to rest of the body) and hormones
2) Transport metabolic waste products from tissues to the excretory system
3) Maintain hemostasis of body temp
4) Hemostasis (blood clotting).
2
Q
Ischemia versus hypoxia.
A
1) Inadequate blood flow that can result in tissue damage due to a shortage of O2 and nutrients, and the buildup of metabolic waste
2) When adequate circulation is present but the supply of O2 is reduced.
3
Q
Difference between arteries, arterioles, and capillaries.
A
Vessels that carry blood away from the heart at a high pressure are ARTERIES. As arteries pass farther from the heart, the pressure of blood decreases, and they branch into increasingly smaller arteries called ARTERIOLES. The arterioles then pass into CAPILLARIES, just wide enough for a blood ell. A
ARTERIOLES have smooth muscle in their wall and can restrict or increase blood flow.
CAPILLARIES are made of thin walls and allows exchange of materials b/t blood and tissue.
4
Q
Arteries -> arterioles -> capillaries
Capillaries -> ____ -> veins
A
Venules
5
Q
The inner lining of all blood vessels is formed by a thin layer of ____. The walls of capillaries are formed from a single layer of such cells.
A
Endothelial cells.
6
Q
Role of endothelial cells - vasodilation/constriction
A
Secretion of particular substances regular diameter of blood vessels. Important for maintaining BP, tissue oxygenation, and thermoregulation.
7
Q
Role of endothelial cells - inflammation.
A
Release of inflammatory chemicals from injured tissues stimulate endothelial cells to increase their expression of adhesion molecules, that allow WBC to stick to the endothelial cells and enter injured tissues.
8
Q
Role of endothelial cells - angionesis.
A
Formation of new blood vessels. Angiogenic growth factors stimulate endothelial cells to break free from an existing vessel altogether.
9
Q
Role of endothelial cells - thrombosis.
A
Thrombosis is blood clotting. Undamaged epethelial cells secrete substances to inhibit coagulation cascade, thus preventing formatin of potentially life threatning clots inside undamaged or unbroken vessels.
10
Q
Why do mammals have two types of circulation.
A
1) Pulmonary circulation:blood flow from heart to to lungs and back to the heart
2) Sytemic circulation: the flow of blood from the heart to the rest of the body and back again
By having two separate circulations, most blod passes through only one set of capillaries before returning to the heart. This avoids the massive pressure drop of capillaries. Exception: portal systems.
11
Q
Define portal systems - exceptions to passing through a single bed of capillaries.
A
Blood passes first through capillaries in the intestine, then collects to veins to travel to the liver, where the vessels branch and again pass through capillaries.
The portal systems evolve as a direct transport sys. to transport nutrients directly from the intestine to liver or hormones from the hypothalamus to the pituitary, without passing through the whole body.
12
Q
The right atrium receives deoxygenated blood from the systemic circulation (from these two veins).
A
Superior and inferior vena cava.
13
Q
Trace the path of blood through the heart.
A
1) The RIGHT ATRIUM receives deoxygenated blood from the systemic circulation and pumps it into the RIGHT VENTRICLE.
2) From the right ventricle, blood passes through the pulmonary artery to the lung.
3) Oxygenated blood from the lungs returns throughthe pulmonary veins to the left artery to the lungs.
4) Oxygenated blood from the lungs returns through the pulmonary veins to the left artrium and is pumped into the leff ventricle before being pumped out the heart in the aorta.
14
Q
Coronary arteries, veins, and sinus.
A
1) Coronary arteries: The first branches of the aorta, which branch to supply blood to the wall of heart
2) coronary veins: deoxygenated blood from the heart collects in the coronary veins, which merge to form the 3) coronary sinus. Blood in the coronary sinus drains directly into the RA.
15
Q
The ventricular pressure of the heart is (high/low) while the atrial pressure is (high/low).
A
The ventricular pressure of the heart is high while the atrial pressure is lower.
16
Q
Function of the atrioventricular valves.
A
The AV valves between each ventricle and its atrium is necessary to prevent backflow.
17
Q
Bicuspid valve.
A
The AV valve between the left atriuma nd ventricle is the biscuspid or mitral valve.
18
Q
Tricuspid valve.
A
The AV valve b/w the right atrium and ventricle is the tricuspid valve.
19
Q
Give the two semilunar valves.
A
The pulmonary and aortic semilunar valves. These are the valves between the large arteries and the ventricles.
20
Q
Where do varicose veins come from?
A
Failed venous valves. Remember the function of the valve is to prevent backflow.
21
Q
Cardiac cycle: diastole.
A
During diastole, the ventricles are relaxed and blood is able to flow into them from the atria. The atria contract during diastole. At the end of diastole, the ventricles contract, initiating systole.
22
Q
Cardiac cycle: systole.
A
Systole begins with ventricle contraction. The ensuing buildup of pressure causes the AV valves to close (lub sound). Over the next few ms, the pressure in the ventricles increase, until the semilunar valves open and blood rushes into the aorta and PA. At the end of systole, the ventricles are nearly empty. As a result, the pressure falls, and a small amount of blood flows backward. The valves shut (dup sound).
23
Q
Explain the lub dup heart sounds.
A
1) lub: results from the closure of AV valves at the beginning of systole
2) dup: results from the semilunar valves closing at the end of systole.
Hence, Diastole is longer than systole.
24
Q
Why do atheletes have slow pulses?
A
They pump more blood each time it contracts. Therefore, it may beat fewer times per minute and still provide adequate circulation. Atheletes have strong hearts.
25
Stroke volume.
The amount of blood pumped with each systole.
26
Cardiac output =?
The total amount of blood pumped per minute, defined by:
| CO (L/min) = SV(L/beat) * HR (beat/min)
27
Which has the larger cardiac output? Right or left ventricle?
They are the same. The same amount of blood must pass through both sides of the heart or blood would back up in either the pulmonary or systemic circulatory system.
28
Two ways to increase cardiac output?
CO = SV * HR --> increase heart rate or stroke volume
***Also a stronger heart has a larger stroke volume
29
What are two ways we can increase stroke volume?
Frank-Starling mechanism: if the heart muscle is stretched, it will contract more forcefully. We accomplish this by increasing venous return, as more blood received means more pumped out. 2 ways to do this:
1) Increase total V of blood in the circulatory sys. Done by retaining water. Dilating arterioles results in more blood flow to tissues and greater return.
2) Contraction of large veins can propel blood toward the heart.
30
What do skeletal muscles, cardiac muscles, and neurons have in common.
All muscle cells, including those of cardiac muscle, share with neurons the ability to propagate an action potential across their surface. The AP in all muscle cells, as in neurons, is a wave of depolarization of the plasma membrane facilitated by voltage-gated ion channels.
31
Cardiac muscle is a functional ____. This is a tissue in which....
Cardiac muscle is a functional syncytium. A syncytium is a tissue in which the cytoplasm of different cells can communicate via gap junctions. In cardiac muscle GJ are found in the intercalated disks, the connections b/t cardiac cells. The depolarization of a cardiac muscle cell can be communicated directly through the cytoplasm (a electrical synapse).
32
In cardiac muscle GJ are found in the _____, the connections b/t cardiac cells.
Intercalated disks.
33
The atria and ventricles have separate syncytia. The action potential in the heart is transmitted from the atrial syncytium to the ventricles by the ____.
Cardiac conduction system.
34
Voltage gated __ and __ channels play an important role in cardiac muscle.
Voltage gated Na+ channels, called fast Na channels.
| Slow Ca channels is involved in cardiac muscle action potential as well.
35
What makes the Ca gated channels in cardiac muscle unique?
Theses channels stay open longer than fast Na channels, causing the membrane to depolarize LONGER in cardiac muscles than in neurons, producing a plateau phase.
36
T tubules.
The maximize the entry of Ca in the cell, cardiac muscle has involutions of the membrane called T tubules. The APs travel down along T tubules, allow the entry of Ca from the EC environment, and also induce the sarcoplasmic reticulum to release Ca.
37
The initiation of each action potential that starts each cardiac cycle occurs automatically within the heart itself, in a special region of the right atrium called the __.
Sinoatrial node. SA node. This is the pacemaker of the heart. The SA node exhibits automaticity.
38
Go through the phases of the SA node.
Phase 4: Unestable resting ψ due to special Na leak channels that are responsible for its rhythmic, automatic excitation
Phase 0: Inward Na leak channels bring cell ψ to the threshold for voltage gated Ca channels to open, and this influx causes the upstroke of the pacemaker.
Phase 3: Repolarization caused by closure of Ca2+ channels and opening of the K+ channels.
The SA node transmits their Ap through the intercalated diks to the rest of the conduction cells in the heart.
39
Go through the phases if membrane ψ in a cardiac muscle cell (not the SA node).
Phase 0) Depolarization - Fast Na channels open transiently; depolarizatoin occur and once threshold is reached, voltage-gated Na opens
Phase 1) Initial repolarization - Gate Na inactivate; K+ channels open and enter
Phase 2) Plateau - intitial Na+ causes opening of slow to open/close Ca2+ channels finally open; gated K+ still open; transient equlibrium in cell ψ here.
Phase 3) Repolarization - Ca2+ closes; Ka+ still open and continues to repolarize
Phase 4) K+ channels close
40
Arrange the following terms regarding the Cardiac Conduction System and comment on how they interact: SA node, AV node, the bundle of his, Purkinje fibers, bundle branches, internodal tracts.
AP in the SA node > internodal tracts > AV node > bundle of His > right and left bundle braches > Puerkinje fibers.
The apex of the heart is the first to contract, given an AP in the SA node. The AP spreads down the special conduction pathway quickly, and spreads to the atria more slowly than the specialized conduction fibers.
41
Regulation of the heart by the autonomic nervous system - role of the parasympathetic NS.
The intrinsic firing of the SA node is 120 beats/min but this is inhibited by the vagus nerve. The vagus nerve contains preganglionic axons which synapse in a ganglia near the SA node. The postganglionoic neurons innervate the SA node and release ACh. ACh inhibits depolarization by binding to receptors on the cells of the SA node. Constant level of inhibition called: vagal tone.
42
Vagal tone.
The constant level of inhibition provided by the vagus nerve is known as vagal tone.
43
Random question: does ACh always inhibit the postsynaptic cell? If not, how can different responses be elicited by the same NT?
ACh is a NT released by ALL autonomic preganglion neurons, all PARAsympathetic neurons, and ALL somatic motor neurons. In most cases it is STIMULATORY (causes an AP to occur or an effect on an organ). BUT, whether a NT is stimulatory or inhibitory is dependent on the nature of the RECEPTOR on the postynaptic cell.
44
Regulation of the heart by the autonomic nervous system - role of the sympathetic NS.
The sympathetic NS affects the heart in two ways:
1) Sympathetic postganglionic neurons directly innervate the heart, releaseing norepinephrine
2) Epinephrine secreted by the adrenal medulla binds to the receptors on cardiac muscle cells.
The effects of sympathetic activation is stimulatory. HR increaes as well as force of contraction.
45
HR and BP are tightly regulated. What unique structure in the heart can give our nervous system clues to fix things?
We have baroreceptors in the aortic arch and carotid arteries than monitor blood pressure.
46
The driving force for blood flow is....
A difference in pressure from arteries to vein.
47
The force opposing blood flow is ___.
Friction.
48
Ohms law to summarize relationship b/t pressure, flow, and resistance.
ΔP = Q *R
```
Q = cardiac output = SV * HR
R = peripheral resistance
```
49
ΔP = Q *R, how can you increase the BP using the Q in the equation
1) increase the force at which the heart conrracts (increase stroke volume)
2) increase the rate of cardiac contraction.
50
ΔP = Q *R; how can you increase/decrease the BP using the R in the equation.
The principle determinant of resistance is the degree of contraction of arteriole smooth muscle, also known as precapillary sphincters. If arteriole SM contracts, it becomes more difficult for blood to flow from arteries into capillaries, so the resistance goes up, resulting in increase BP.
51
Adrenergic tone.
A certain amount of pressure in the arteriole system is always desirable to keep all tissues perfused. The constant level of norepinephrine rleased by millions of sympathetic postganglionic axons innervating precapillary sphincters.
52
Systolic versus diastolic pressure.
Systolic pressure: the highest pressure that occurs in the cirulatory sys; this is recorded as the ventricles contract (during systole)
Diastolic pressure: the lowest the arterial pressure is occuring at any time during the cardiac cycle (during diastole - between heart beats).
53
Blood pressure is actually a measure of ___.
Systemic arterial pressure; the force per unit area exerted by blood upon the walls of the arteries.
54
Explain the sounds of the sphygmomanometer.
A nurse inflates a cuff until no blood flows into the arm (silence is heard through the stethscope). Then, he gradually reduces the cuff pressure, until a pulse first becomes audible. This is the sysolic pressure on the manometer. The systolic is just greater than the pressure of the cuff. You can hear the pulse now, as the blood is slammed against the arteries. Then the nurse continues to deflate, untli the pulse becomes more quiet. Now the cuff is loose, so blood flows smoothly. When the pulse is inaudible, it's written as the diastolic.
55
In the cardiac cycle, what's the pressure of the vena cava?
It is typically around 0 mmHg. The pressure is highest in the left ventricle and other large arteries, and then it dissapates as blood flows through the ciruclatory system. By the time it reaches the vena cava, it depends on valves to prevent backflow because blood pressure would be negligible.
56
Local autoregulation's function.
The nervous system doesn't control blood flow to every single region of the body. Too much energy would be expended. Instead, tissues in need of extra blood can obtain it. Certain metabolic waste have effects on arteriole SM, causing it to relax. Hence, when a tissue is underperfused, waste builds up, and vasodilation occurs.
57
The cellular elements of blood.
The cellular elements of blood are known as formed elements. These are RBCs, leukocytes (WBCs). All formed elements of the blood develop from special cells in the bone marrow.
58
Components of blood: percent/components. Hint: there are three.
Plasma - 55%; composed of the following dissolved in water: electrolytes, buffers, sugars, blood proteins, lipoproteins, CO2, O2, metabolic waste (like urea)
Hematocrit - 45% in men; 40% women. This is the volume of blood occupied by RBCs
Leukocytes - 1% - WBCs and platelets.
59
Plasma proteins - albumin, fibrinogen, lipoproteins, urea, bilibrubun, immunoglobulins
1) albumin - essential for maintaining oncotic pressure (osmotic pressure in the capillaries due only to plasma proteins).
2) fibrinogen - essential for blood clotting
3) lipoproteins - particles consisting of fat, cholesterol, and carrier proteins
4) bilirubin - a breakdown product of heme
5) urea - metabolic waste product from protein breakdown
6) immunoglobulin - part of immune sys; antibody
60
Where are erythrocytes, leukocytes, and platelets derived from?
bone marrow stem cells
61
Serum versus plasma.
If whole blood is allowed to clot, one is left witha solid clot plus clear fluid known as serum. This is similar to plasma minus all the proteins involved in clotting.
62
Erythropoetin.
A hormone made in the kidney that stimulates RBC production in the bone marrow.
63
What is within the a erythrocyte cell?
RBCs have no nucleus or other organells such as mitochondria. It requires ATP for processes such as ion pumping and basic maintaenance of cell structure, and accomplishes this via glycolysis. It has millions of molecules of Hgb to carry O2.
64
If RBCs don't have mitochondria, where does the cell get its energy?
RBCs rely on glycolysis for ATP synthesis.
65
The lifetime of a RBC in the bloodstream?
120 days
66
The function of RBC.
The RBC has high surface to volume ration; it is responsible for transporting O2 to the tissues from the lungs and CO2 from the tissues to the lungs. The RBC can carry O2 bc it contains millions of hemoglobin
67
Where are erythrocytes degraded?
It is degraded by phagocytes in the spleen and liver.
68
Two blood group antigens use for blood typing.
ABO blood group, coded by Ia, Ib, and Ii > produced prior to exposure. A produces B antibodies.
Rh blood group > like many cells of the immune system., the Rh antigen isn't produced unless a personw ith Rh- blood is exposed to Rh+ blood, which can happen at chilbirth.
69
An Rh- mother's baby is Rh+. What can be done to prevent hemolytic disease of the future Rh+ babies?
During childbirth, the mother can be injected with Rh+ antibodies, which destroys Rh+ cells from the baby.
Rh is a problem when a Rh- mother is exposed to Rh+.
70
Universal recipient and donor.
AB+ = universal recipient; won't produce A,B antibodies; also will not prodyce Rh - antibodies.
O- = universal donor = can donate blood to any othe blood type.
71
Which leukocytes move by amoeboid motility. Why is this beneficial?
Neutrophils and macrophages. This is important bc they are able to squeeze out of capillary intercellular junctions and roam free in tissues, hunting for foreign particles and pathogens.
72
Chemotaxis.
Movement directed by chemical stimuli. Some WBC exhibit this - chemical stimuli can be toxins and waste products relase by pathogens, or can be chemical signals released form other
2) T cell - kill virus infected cells, tumor cells, and reject tissue grafts, also control WBCs.
73
Leukocyte - Lymphocytes.
White blood cells:
| 1) B cell - mature into plasma cell and produce antibodiesimmune response.
74
Leukocyte - Monocytes.
Macrophage - phagocytose debris and micoorganism amoeboid motility; chemotaxis
75
Leukocyte - Grannulocytes: neutrophil, eosinophil, basophil
1) Neutrophil - phagocytose bactertia resultingin pus; amoeboid motility, chemotaxis.
2) Eosinophil - destroy parasites
3) Basophil - store and release histamine, allergic reaction
76
Hemostasis - body's mechanism of preventing bleeding.
| Connect fibrin, thrombin, and fibrinogen.
The plasma protein FIBRINOGEN is converted into FIBRIN by a protein called THROMBIN. Fibrin is a threadlike protein which forms a mesh that holds the platelet plug together.
77
What are the contents of platelets? Where do they come from?
Platelets, like RBCs, have no nuclei and a limited lifespan. They are derived from fragmentation of bone marrow cells called megakaryocytes, which are derived from the same stem cells that give rise to RBCs.
78
Two states of hemoglobin subunits and their affinity for O2.
Tense - the 4 hemoglobin subunits form a tense confirmation that has a relatively low affinity for oxygen.
Relaxed - higher affinity for oxygen
79
Hemoglobin exhibits ___, as the binding of one subunit, stimulates the others to change their conformation to increase their affnity fo O2 as well.
Cooperativity.
80
Where does Hgb have low/high affinity for binding O2: lungs or tissue?
In the tissues, hgb has low affinity for O2 and tends to release O2 which it carries. The level of O2 in the lungs is of course very high, and it will have a high affinity for O2 there, so it can pick up O2 to transort to tissues.
81
Bohr effect.
The factors that stabilze tense hgb and thus reduce it O2 affnity is known as the Bohr effect.
These three factors stabilize the tense state:
1) decreased pH = cells running low on O2 produce lactate to make energy
2) increased pCO2 = meetabolism of a lot of glucose results in increase CO2
4) increased temp = more metabolic activity
82
Describe the left and right shifts of the O2- Hemoglobin Dissociation Curve.
Curves farthest left represens the highest affinity. Fetal hgh has high affinity, and would be left shifted. This is more likely to be seen in the lungs.
Curves farthest right could represent the Bohr affect, where hgb has LOW affinity for O2.
83
CO2 is transported in the blood three ways:
1) 73% is transported by conversion of CO2 into carbonic acid, which can dissociate into bicarbonate and H+
CO2 + H2O H2CO3 HCO3 + H+
2) 29% is transported by being stuck to other sites of hgb. Binding of CO2 stabilizes tense hgb
3) 7% is dissolved in the blood, unlike O2, which cannot dissolve in the blood
84
Describe the anatomy of capillaries in terms of the cell makeup and the spaces between the cells.
Capillaries have a wall of only a single layer of flattened endothelial cells, and there are spaces called intercellular clefts b/t the endothelial cells that make u the capillary wall.
85
Name the three substancs that must be able to pass through the intercellular clefts between cells in the capillary walls.
Nutrients, salts, wastes, and white blood cells.
86
How does O2 and CO2 enter a cell?
They can pass straight through any cell by simply diffusion.
87
Hepatic portal vein.
AAs and glucose are absorbed from the DG tract carried by a special vein called the HPV. It's called a portal vein bc it connects two capillary beds: one in the intestinal wall andone inside the liver. The liver stores AA and glucose until they are needed.
88
Many wastes are produced during metabolism. They diffuse through capillary walls into the bloodsream and the __ removes and converts them into forms which can be excreted in the feces. Such compounds are passed into the gut as __.
Liver and bile. Other wastes are excreted by the kidneys.
89
Water has a great tendeny to flow (out/in) of the capillaries. Name the two reasons.
Water has a greater tendency to flow OUT of the capillaries because 1) hydrostatic pressure created by the heart squeezes water out, and 2) the high osmolarity of the tissues tends to draw water out of the bloodstream
90
How does the circulatory system deal with the tendencey to lose water to tissues?
The plasma has a high osmolarity because of the presence of large plasma proteins that cannot enter flow through the capilaries, mainly albumin. The osmotic pressure provided by the plasma proteins is called ONCOTIC PRESSURE. Some water always leaks out, but not all.
91
Albumin is made in the liver. Alcoholics with diseaed livers make insuffieint amoutns of albumin. How would this affect the body?
Albumin is important for maintainng a high oncotic pressure. Water has a tendency to move out of tissues because of the pressure created by the heart and the high osmolarity of the tissues. Albumin is large and increases the osmolarity of the blood. Without this, water will move into tissues, causing edema of the entire body.
92
True or false. The lympatic system is a circulatory system.
It is a ONE way flow system that begins with tiny capillaries from the tissues of the body that merge to form larger lymphatic vessels. They merge to form large lymphatic ducts.
93
Function of lymph nodes.
Lymph nodes are important part of the immune sys. because they contain millions of WBCs that can initate an immune response aganist anything foreign picked up in the lymph. The
94
Large lymphatic ducts merge to form the ____, which is the largest lymphatic vessel. This empties into a large vein near the neck.
Thoracic duct.
95
Functions of lymphatic system:
1) immune defense at lymph nodes and picking up debris/bacteria/toxins in lymph
2) dumping dietary fats in the form of chylomicrons into the thoracic duct
3) Retrieve water, proteins and blood cells from the tissues.
96
Innate immunity.
General, NONSPECIFIC protection the body provides against various invaders...
97
5 principal components of innate immunity.
1) skin - barrier against microorganisms
2) Tears, saliva, blood contains lysozyme, and EZ that kills some bacteria by destroying their cell walls
3) Extreme acidity of the stomach destroys many pathogens
4) Macrophages and neutrophils indiscriminately phagocytize microoganisms
5) The complemenet system - a group of 20 blood proteins that nonspecifically bind to the surface of foren cells, leading to their destruction.
98
Complement system.
A system composed of a group of 20 blood proteins that nonspecifically bind to the surface of foren cells, leading to their destruction. Part of INNATE immunit.
99
Humoral immunity.
SPECIFIC protection by proteins in the plasma called antibodies (Ab) or immunoglobulins (Ig). Abs specifically recognize and bind to microorganisms (or other forein particles) leading to their destruction and removal from the body.
100
Anatomy of an antibody.
2 light chains and 2 heavy chains with variable (antigen binding) regions and constant regions.
These chains are joined via disulfide bonds.
101
Different classes of immunoglobulin vary by constant region: IgM - location inbody and function.
Location: Blood and b cell surface
Function: Initial immune response, pantameric structure in blood; monomeric on B cell surface
102
Different classes of immunoglobulin vary by constant region: IgG - location inbody and function.
Location: blood
Function: ingolved in ongoing immune response; majority of Abs in the blood is IgG; can cross placental barrier
The GA GA passes the placental barrier.
103
Different classes of immunoglobulin vary by constant region: IgD - location inbody and function.
Location: B cell surface
Function: Serves with IgM as antigen receptor on B ells
104
Different classes of immunoglobulin vary by constant region: IgA - location inbody and function.
Location: secretions (saliva, mucus, tears, breast milk)
Function: Secreted inbreast milk; help protect newborns
The GA GA passes the placental barrier.
105
Different classes of immunoglobulin vary by constant region: IgE - location inbody and function
Location: blood
Function: involved in allergic reactions
106
What makes humoral immunity different from innate?
Each antibody forms a unique variable region that has a different specificity. Innate immunity is nonspecific.
107
Antigen.
Molecule that an antibody binds to (ex. capsid proteins; bacerial surface proteins; toxins in the blood).
108
Would an Ab against a cytoplasmic bacterial protein help the immune system to remove the bacteria?
No. Abs are soluable in the PLASMA, so they can only recognize antigens on teh surfaces that are accessible to them. A protein in the cytoplasm of a bacteria would be accessible to antibodies in the plasma.
109
If an antigen binding site is small, can Ab recognize large proteins as antigens.
Yes. Antigens are often large moelcules which have many different recgonition sites for different antibodies. The small site than an Ab reconizes within a large molecule is called an epitope.
110
An antibody might bind tightly to a small region of a protein consisting of 200 AA acids, but won't have the same binding affinity with the isolated small region. Why?
The intract protein the 5 AA assume a specific 3D conformation that is recognized well by the Ab. The give AA as a small peptide will not fold the same way and probably won't be as well recognized by the Ab.
111
Does the genome encode a gene for every possible antibody molecule? A million genes for a million different potential antibodies.
Two different antibodies do NOT have the same genes. During B cell development, genes that encode antibody proteins are assembled by recombination from many small segments. Thus, there are MANY different B cells, each encoding different variable regions. There's just a shit ton of different B cells in your body, so the changes 1/100000000000 B cells can attach to a novel virus increases.
112
When antigen binds to the antibody, what happens?
When antigen binds to the surface of a specific immature B cell, that cell is stimulated to proliferate and differentiate into plasma and memory cells.
113
Humoral immunity - Plasma cells ( a type of B cell).
Plasma cells actively produce and secrete antibody protein into the plasma.
114
Humoral immunity - Memory cells ( a type of B cell)
Memory cells are produced from the same clone and have the same varaible regions of the activated B ell, but they don't secrete antibody; they are pre-activated dormant B cells. They remain dormant until the antigen reappears. If they do get reactivated, they produce Ab VERY quickly.
115
When an antibody binds to an antigen, the following can contribute to the removal of the antigen.
1) Binding of Ab may directly inactivate the antigen.
2) Binding of Ab can induce phagocytosis from macrophages and neutrophils
3) Presence of Ab on the surface of a cell can activate complement to form holes in the cell MB and lyse the cell
116
Clonal selection.
Clonal selection is a process proposed to explain how a single B or T cell that recognizes an antigen that enters the body is selected from the pre-existing cell pool of differing antigen specificities and then reproduced to generate a clonal cell population that eliminates the antigen.
117
In general, every cell of the body is said to possess the same copy of the genome. Is this true of the immune system?
NO, this is an exception. Recombination during the dvelopment of B and T cells amkes these an exception to the gneralization that every cell contains the whole genome.
118
Primary versus secondary immune response.
Primary - the first time someone encounters an antigen during an infection; it can take a week or more for B cells to proliferate and secrete significant elvels of Ab
Secondary - much swifter and stronger respose, since the person has already been exposed and has memory cells from the first infection.
119
Two types of T cells and their functions.
1) T helpers (CD4) - activate B cells, T killers, and other cells of the immune system. Communicates with others by special hormones call lymphokines and interleukins
2) T killers (CD8) - destroy abnormal host cells (virus, cancer, and foreign cells such as skin graft from incompatible donors
120
Interlukins and lymphokines.
Special hormones produced by CD4 helper T cells to activate other cells of the immune system (B, killer T,etc)
121
Where are T cells made?
They are initially produced in the bone marrow, and each of these is specific to a particular antigen, just like B cells.
T cells are produced in the bone marrow and later move to the thymus where they mature.
122
What is the role of MHCs?
MHC1 and MHC2 are proteins found on the surface of cells, their role is to pick up peptides from the inside of the cell and display them on the cell surface. This allows T cells to monitor cellular components.
123
What is the specific role of MHC 1 in terms of interacting with cytotoxic CD8 T cells?
If a cell is infected with a virus, one of its class 1 MHC complexes will display a piece of a virus-specific protein. When a killer T cell detects the viral protein by binding to the displayed peptide, it becomes activated and will proliferate.
124
What is the specific role of MHC 2 in terms of interacting with CD4 helper T cells.
Only certain cells have MHC 2. These cells are known as antigen presenting cells (macrophages and B cells). Their role is to phagocytize particles or cells, and display fragments using the MHC 2. T helpder cells then bind to this complex. After a CD4 cell is activated, it will activate B cells and stimulate proliferation of killer T cells specific for the antigen.
125
Spleen role in the immune system.
The Spleen filters blood and is the site of immune cell interactions, just like lymphp nodes.
126
Lymph nodes role in the immune system.
Also filters blood and is the site of immune cell interactions
127
Tonsils and appendix role in the immune system.
Masses of lymphatic tissue in the back of the throat that help catch pathogens which enter the body through respiration of ingestion.
The appendix is siilarin function to the tonsil, located at the beginning of the colon.
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How does the body typically rid of self-reactive cells, before they reach the bloodstream and cause autoimmune inflammation?
An immature B cell whose surface receptors binds to normal cell surface protein is induced to die through apoptosis. Those who bind to normal soluble proteins like hgb don't go through apoptosis but become unresponsive or anergic. Only B cells whose surface receptors bind to abnormal proteins during maturation are released.
For T cells, the process is similar but occurs in the thymus or lymph nodes.
