2025 Physiology Exam 2 Flashcards

Question

Venous Return and Cardiac Output Must be Equal

Answer 1

Venous return is the quantity of blood flowing from the veins into the right atrium each minute. ... it doesn't seem to be equal because of how some blood goes to lungs Cardiac output is the quantity of blood pumped into the aorta each minute by the heart. This is also the quantity of blood that flows through the circulation. Cardiac output is the sum of the blood flows to all the tissues of the body.

Answer 2

More the heart receives, the more it will pump out Cardiac output is controlled by venous return. Various factors of the peripheral circulation that affect flow of blood into the heart from the veins are the primary controllers of cardiac output. Factors: Muscle Contraction Gravity Size of the lumen of the vessels

Answer 3

Three principal factors that affect venous return to the heart from the systemic circulation: Right Atrial Pressure, which exerts a backward force on the veins to impede flow of blood from the veins into the right atrium. Degree of filling of the systemic circulation (measured by the mean systemic filling pressure), which forces the systemic blood toward the heart (this is the pressure measured everywhere in the systemic circulation when all flow of blood is stopped). Resistance to blood flow between the peripheral vessels and the right atrium (resistance to venous return)

Answer 4

Two thirds of the so-called resistance to venous return is determined by venous resistance, and about one third is determined by the arteriolar and small artery resistance. A decrease in this resistance to one-half normal allows twice as much flow of blood and, therefore, rotates the curve upward to twice as great a slope. Conversely, an increase in resistance to twice normal rotates the curve downward to one-half as great a slope. Venous Resistance is the #1 effector Q= 1/R

Answer 5

The P wave immediately precedes atrial contraction. The QRS complex immediately precedes ventricular contraction. The ventricles remain contracted until a few milliseconds after the end of the T repolarization wave. The atria remain contracted until repolarized, but an atrial repolarization wave cannot be seen on the EKG because it is obscured by the QRS wave. The P-Q or P-R interval on the electrocardiogram has a normal value of 0.16 seconds (0.12–0.20). It is the duration of time between the beginning of the P wave and the beginning of the QRS wave. This represents the time between the beginning of atrial contraction and the beginning of ventricular contraction. The Q-T interval has a normal value of 0.36 seconds (0.36–0.40, QTc ≤ 0.46) and is the duration of time from the beginning of the Q wave to the end of the T wave This approximates the time of ventricular contraction. The heart rate can be determined with the reciprocal of the time interval between each heartbeat. R-R interval = 0.83 sec Heart rate = (60 sec)/(0.83 sec) = 72 beats/minute

Answer 6

Ventricular depolarization starts at the ventricular septum and the endocardial surfaces of the heart. The average current flows positively from the base of the heart to the apex. At the very end of depolarization the current reverses from 1/100 second and flows toward the outer walls of the ventricles near the base (S wave).

Answer 7

The current in the heart flows from the area of depolarization to the polarized areas (from − to +). The electrical potential generated can be represented by a vector, with the arrowhead pointing in the positive direction. The length of the vector is proportional to the voltage of the potential. The generated potential at any instance can be represented by an instantaneous mean vector. The normal mean QRS vector is about 59 degrees.

Answer 8

Begins at sinus node and spreads toward A-V node. This should give a + vector in leads I, II, and III.

Answer 9

Hypertrophy of right ventricle (right axis shift) is caused by pulmonary hypertension, pulmonary valve stenosis, and interventricular septal defect. All cause slightly prolonged QRS and high voltage.

Answer 10

Amount of Blood Size of vessels

Answer 11

Transporting nutrients to the tissues Transporting waste products away from the tissues Transporting hormones

Answer 12

Most Blood is in the Venous System

Answer 13

Slows the BP as they are smaller

Answer 14

Internal Respiration Small to the size RBCs must go through them 1 by 1

Answer 15

The reservoir of blood The Pressure is low

Answer 16

Site of gas exchange External Respiration Respiratory membrane makes this happen

Answer 17

Capillaries have smallest velocity of blood Velocity is inversely proportional to cross sectional area

Answer 18

Blood flow to tissues is controlled in relation to tissue needs. Cardiac output is mainly controlled by local tissue flow. Arterial pressure is controlled independent of either local blood flow control or cardiac output control.

Answer 19

Flow is inversely proportional to resistance Inflammation leads to vasodilation, decrease in resistance, increase in flow

Answer 20

These causes are the causes of blood clots as well Murmurs - noises in the heart Bruits - noises in the vessels

Answer 21

Veins are 8x more distensible than arteries

Answer 22

Veins have more capacitance

Answer 23

Any given change in volume within the arterial tree results in larger increases in pressure than in veins. When veins are constricted large quantities of blood are transferred to the heart thereby increasing cardiac output. Add more volume of blood to arteries as veins, more pressure in arteries due to their structure

Answer 24

First noise is the Systolic Once noise disappears, that is diastolic Result of turbulent blood flow

Answer 25

Each tissue controls its own blood flow in proportion to its needs. Tissue needs include: Delivery of oxygen to tissues Delivery of nutrients such as glucose, amino acids, etc. Removal of carbon dioxide hydrogen and other metabolites from the tissues Transport various hormones and other substances to different tissues Flow is closely related to metabolic rate of tissues.

Answer 26

Increases in tissue metabolism lead to increases in blood flow. Decreases in oxygen availability to tissues increase tissue blood flow. Two major theories for local blood flow are The vasodilator theory Oxygen demand theory

Answer 27

Q = ∆P/R Flow (Q) through a blood vessel is determined by: The pressure difference (∆P) between the two ends of the vessel Resistance (R) of the vessel

Answer 28

OXYGEN IS THE IMPORTANT TAKE AWAY

Answer 29

Angiogenesis is the growth of new blood vessels.

Answer 30

Vasoconstrictors Norepinephrine and epinephrine Angiotensin II Vasopressin Endothelin Vasodilator agents Bradykinin Serotonin Histamine Prostaglandins Nitric oxide

Answer 31

Modified according to the needs Redistribution of blood flow Increasing pumping activity of the heart Rapid control of arterial pressure Regulates via the autonomic nervous system (Visceral Efferent or Visceral Motor) Sympathetic - constrict blood vessels (chronotropic and inotropic effects of the heart) Parasympathetic - dilate blood vessels

Answer 32

Sympathetic chain ganglia on left side of spine. Sympathetic only go to blood vessels Sympathetic comes from T1 - L5 Parasympathetic comes out of cranial and sacral Parasympathetic goes to the heart

Answer 33

Vaso contrict = increase resistance

Answer 34

In the brain stem

Answer 35

Postsympathetic fiber and effector organ (LOOK INTO MORE???) The neurotransmitter for the vasoconstrictor nerves is norepinephrine. Adrenal medulla secretes epinephrine and norepinephrine which constricts blood vessels via alpha adrenergic receptors. Epinephrine can also dilate vessels through a potent β2 receptor.

Answer 36

Pressoreceptors

Answer 37

YOUTUBE THIS MORE!!! Normal Capillary hydrostatic pressure is approximately 17 mm Hg. Interstitial fluid pressure in most tissues is negative 3. Encapsulated organs have positive interstitial pressures (+5 to +10 mm Hg). Negative interstitial fluid pressure is caused by pumping of lymphatic system. Colloid osmotic pressure is caused by presence of large proteins.

Answer 38

YOUTUBE THIS MORE!!!

Answer 39

Bitter are located in back of mouth

Answer 40

Know they are on Papillae

Answer 41

Know the Cranial Nerves Know the Thalamus purpose in Taste

Answer 42

Taste sensations adapt rapidly. Adaptation of taste buds themselves accounts for only about 50% of the adaptation. Central adaptation must occur but the mechanism for this is not known.

Answer 43

Least understood of all senses. Poorly developed in humans. Olfactory membrane located on the superior part of each nostril. Contains olfactory cells which contain cilia. On the cilia are odorant-binding protein receptors. Binding of chemical odorant to receptor induces the G-protein transduced formation of cAMP which opens sodium channels.

Answer 44

Substance must be volatile so that it can be sniffed into nostrils. Substance must be at least slightly water soluble to penetrate the mucus to reach the olfactory cells. Substance must be at least slightly lipid soluble to interact with the membrane. Olfactory receptors adapt very slowly. But olfactory sensation itself adapts rather rapidly. Hence, must involve a central mechanism.

Answer 45

Located in the temporal cortex Coming to and from CN I

Answer 46

Biconcave discs Men: 5,200,000 (±300,000)/mm3 Women: 4,700,000 (±300,000)/mm3 RBC counts can be increased at higher altitudes.

Answer 47

Normal hemoglobin concentration is 34 g per 100 mL of packed cells. Normal hematocrit (packed cell volume) is 40–45% (slightly lower in women). KNOW THIS!!! Thus normal hemoglobin is 14–15 g per 100 mL of blood. O2 carrying capacity is 1.34 mL/g Hgb, or 19–20 mL O2/100 mL blood.

Answer 48

First few weeks of gestation—yolk sac Mid-trimester—liver (+ spleen, lymph nodes) Last month of gestation through adulthood—bone marrow

Answer 49

Pluripotent hematopoietic stem cells give rise sequentially to committed stem cells and mature cells. Driven by Growth inducers (factors; e.g., interleukin-3) Differentiation inducers Hematopoiesis responds to changing conditions. Hypoxia: erythropoiesis Infection/inflammation: WBC production

Answer 50

1% of RBCs in the body are Reticulocytes (Retics)... still have organelles in them before Erythrocytes

Answer 51

Body tissue isn't getting enough O2, body says produce more RBCs to carry more O2

Answer 52

Sustained hypoxia can result in red cell mass above the usual normal range … Prolonged stay at high altitude Lung disease Heart failure

Answer 53

Circulating hormone, mw ~34,000 Necessary for erythropoiesis in response to hypoxia ~90% made in the kidney Cells of origin not established Hypoxia → HIF-1 → binds hypoxia response element → ↑ Epo transcription Extra-renal hypoxia can stimulate Epo production … epinephrine, norepinephrine, and some prostaglandins can promote Epo production. In anephric individuals, 10% residual Epo (mainly from liver), supports 30–50% needed RBC production … Hematocrit (packed cell volume) ~23–25% rather than 40–45% KNOW THIS IS THE HORMONE RESPONSIBLE FOR RBC PRODUCTION AND PRIMARILY PRODUCED IN KIDNEYS Minutes to hours … ↑ Erythropoietin New circulating RBCs … ~5 days Thus, erythropoietin … stimulates production of proerythroblasts from HSCs accelerates their maturation into RBCs Can increase RBC production up to 10× normal Erythropoietin remains high until normal tissue oxygenation is restored.

Answer 54

Rapid, large-scale cellular proliferation requires optimal nutrition. Cell proliferation requires DNA replication. Vitamin B12 and folate both are needed to make thymidine triphosphate (and thus DNA). Abnormal DNA replication causes failure of nuclear maturation and cell division … → maturation failure → large, irregular, fragile “macrocytes” NEED THESE TO PRODUCE RBCs

Answer 55

Occurs from proerythroblast through reticulocyte stage Reticulocytes retain a small amount of endoplasmic reticulum and mRNA, supporting continued hemoglobin synthesis.

Answer 56

Each globin chain is associated with one heme group containing one atom of iron. Each of the four iron atoms can bind loosely with one molecule (two atoms) of oxygen. Thus each hemoglobin molecule can transport eight oxygen atoms.

Answer 57

Modest differences in O2 binding affinities Sickle hemoglobin: Glutamic acid → Valine at AA 6 (Gives resistance against Malaria) Hemoglobin of homozygous individuals (SS) forms elongated crystals when exposed to low O2. → hemolysis, vascular occlusion

Answer 58

Must be loosely bound—binding in settings of higher O2 concentration, releasing in settings of lower concentration. Binds loosely with one of the coordination bonds of iron Carried as molecular oxygen (not as ionic oxygen) The iron binds to the O2

Answer 59

Iron is a key component of hemoglobin, myoglobin, and multiple enzymes (cytochromes, cytochrome oxidase, peroxidase, catalase). Thus iron stores are critically regulated. Total body iron ~4–5 g 65% in hemoglobin 4% in myoglobin 1% in intracellular heme compounds 0.1% associated with circulating transferrin 15–30% stored mainly as ferritin in RES

Answer 60

Absorbed from small intestine where it binds to apotransferrin → transferrin (transport iron) Iron can be released to any cell. RBC precursors have transferrin receptors and actively accumulate iron. Particularly in hepatocytes and reticulo-endothelial cells, iron combines with apoferritin → ferritin (MW 460,000). Ferritin is variably saturated (storage iron). Hemosiderin is quite insoluble excess iron. When iron in the plasma is low, iron is released from ferritin and bound to transferrin for transport. It is delivered to the bone marrow, bound by transferrin receptors on erythroblasts, internalized, and delivered directly to the mitochondria for incorporation into heme.

Answer 61

RBC life span is ~120 days Though lacking a nucleus, mitochondria, and endoplasmic reticulum, RBCs have enzymes that can metabolize glucose and make small amounts of ATP. These enzymes … maintain membrane pliability. support ion transport. keep iron in the ferrous form (rather than ferric). inhibit protein oxidation. As enzymes deplete with age, RBCs become fragile and rupture in small passages, often in the spleen.

Answer 62

When RBCs rupture, hemoglobin is phagocytosed by macrophages, particularly in the liver and spleen. Iron is released back to transferrin in the blood to support erythropoiesis or be stored as ferritin. Macrophages convert the porphyrin portion, stepwise, into bilirubin, which is released into the blood and secreted by the liver into the bile.

Answer 63

Red blood cell surface antigens: glycolipids or glycoproteins Present on all cells in the body, not just blood cells Agglutinogens: surface antigens (A,B) Genes: A, B, O (maternal, paternal alleles) Genotypes: OO, OA, OB, AA, BB, AB Agglutinins (immunoglobulins): anti-A, anti-B

Answer 64

Requires prior exposure to incompatible blood Six common antigens (“Rh factors”) C, D, E, c, d, e Each person is CDE, CDe, Cde, CdE, cDE, cDe, or cde D (“Rh positive”) is prevalent (85% EA, 100% Africans) and particularly antigenic C and E can also cause transfusion reactions, generally milder

Answer 65

Encoded by the MHC Six classes, total of >150 antigens expressed on all nucleated cells MHC Class I: HLA-A, -B, and -C MHC Class II: HLA-DP, -DQ and –DR Seek the best match possible among the closest relatives possible Important to Organ Transplants

Answer 66

Vascular constriction Formation of a platelet plug Formation of a blood clot Healing of vascular damage ± recanalization

Answer 67

Virchow's triad is a theory that three factors contribute to blood clotting, or thrombosis. The factors are: Hypercoagulability: The blood's tendency to clot Stasis: Abnormal blood flow or pooling Endothelial injury: Damage to the lining of blood vessels

Answer 68

Myogenic spasm Local autocoid factors from damaged tissues and platelets Nervous reflexes Smaller vessels: thromboxane A2 released by platelets

Answer 69

Contractile capabilities Actin, myosin, thrombosthenin Residual ER and Golgi Synthesize enzymes, prostaglandins, fibrin-stabilizing factor, PDGF, store Ca++ Mitochondria/enzymes Produce ATP, ADP

Answer 70

Contact with damaged endothelium Assume irregular forms Contract and release granules (ADP, thromboxane A2) Adhere to collagen and vWF Other platelets accumulate, adhere, and contract, form plug, initiate clotting Very low platelets → petechaiae, bleeding gums

Answer 71

Begins in 15–20 seconds in severe vascular trauma Occlusive clot within 3–6 minutes unless very large vascular defect 20–60 minutes: Clot retraction 1–2 weeks Invasion by fibroblasts Organization into fibrous tissue

Answer 72

Look into this more Youtube!!! KNOW THIS SLIDE!!!

Answer 73

Makes a mesh work around the platelet plug This mesh work traps RBCs in it

Answer 74

Thrombin (weak protease) cleaves four small peptides from fibrinogen → Fibrin monomer → spontaneous polymerization Long fibers form clot reticulum Fibrin stabilizing factor In plasma and released from platelets Activated by thrombin Covalent cross-linking of fibrin monomers and adjacent fibrin fibers

Answer 75

Thrombin is bound to platelets and trapped in the clot Can act on prothrombin to generate more thrombin (positive feedback) Thrombin also produces more prothrombin activator by acting on other clotting factors Additional fibrin monomers and polymers are generated at the periphery of the clot

Answer 76

Begins within 20–60 minutes Fibrin binds to damaged vessel wall Platelets bind to multiple fibrin fibers Contract via actin, myosin, thrombosthenin Clot tightens, expressing serum, and closing the vascular defect Serum is the blood without the cells and clotting factors, so when the clot retracts it squeezes out what is left... the clear, yellowish fluid = serum

Answer 77

Two pathways Extrinsic pathway—Trauma to vessel wall and adjacent tissues Intrinsic pathway—Trauma to the blood or exposure of the blood to collagen Both pathways involve “clotting factors”—mostly inactive proteases that are activated in cascades

Answer 78

Know the last steps with all the Prothrombin

Answer 79

Tissue injury … Tissue factor activates the Extrinsic Pathway Exposure of Factor XII and platelets to collagen activates the Intrinsic Pathway Extrinsic pathway can be explosive, with clotting in <15 seconds The Intrinsic pathway is slower → 1–6 minutes Common Point is the Prothrombin Activator (Fibrin Strands?)

Answer 80

Plasminogen is trapped in the clot. Over several days, injured tissues release tissue plasminogen activator (tPA). Plasminogen is activated to plasmin, a protease resembling trypsin. Plasmin digests fibrin fibers and several other clotting factors. Often results in reopening repaired small blood vessels Vitamin K = big in clotting factors (deficiency is not good)

Answer 81

Low numbers of platelets

Answer 82

Bleeding Time (from small cut) Normally 1– 6 minutes Largely reflects platelet function... they are first on scene Clotting time Invert tube every 30 seconds Normally 6–10 minutes Not reproducible, generally not used... reflects the coagulation

Answer 83

Add excess calcium and tissue factor to oxalated blood, measure time to clot Assesses Extrinsic and Common Pathways Usually about 12 seconds

Answer 84

Our world is teeming with microorganisms, which can be beneficial or harmful. Phagocytes can ingest and destroy invading organisms, and participate in tissue reactions that “wall off” infection. Other white cells (lymphocytes, next chapter) mediate responses that destroy or neutralize specific microorganisms.

Answer 85

Total WBC ~7,000/mm3 (almost 1000-fold fewer than RBCs) Proportions: Neutrophils 62% Eosinophils 2.3% Basophils 0.4% Monocytes 5.3% Lymphocytes 30% *** Know Neutrophils and Basophils proportions Platelets ~300,000/mm3

Answer 86

Lymphocyte - the big one with whole nucleus Neutrophil - horseshoe, multi nucleus

Answer 87

Granulocytes and monocytes develop in the bone marrow, and most remain there until needed peripherally (number in marrow ~3× blood; 6-day supply). Lymphocytes develop mostly in the peripheral lymphoid organs (thymus, spleen, tonsils, lymph nodes, Peyer’s patches). Megakaryocytes develop and reside in the marrow, fragment to release platelets.

Answer 88

Neutrophils are mature cells that can respond immediately to infection. Monocytes mature in the tissues to become macrophages. Both exhibit motility: Diapedesis Ameboid motion Chemotaxis (chemoattractants: bacterial or tissue degradation products, complement fragments, other chemical mediators)

Answer 89

“Phagocytosis” is the ingestion of particles. Phagocytes must distinguish foreign particles from host tissues. Appropriate phagocytic targets: May have rough surfaces Lack protective protein coats May be immunologically marked for phagocytosis by antibodies or complement components that are recognized by receptors on the phagocytes … this immunologic marking is called “opsonization”

Answer 90

After being activated in the tissues, macrophages are extremely effective phagocytes (up to ~100 bacteria). They can ingest larger particles … Damaged RBCs Malarial parasites Macrophages can extrude digestion products and survive and function for many more months. In both neutrophils and macrophages, phagosomes fuse with lysosomes and other granules to form phagolysosomes (digestive vesicles). These contain proteolytic enzymes, and in macrophages, lipases (important in killing tuberculosis bacillus and some other bacteria). Bacteria may be killed even if they are not digested. Enzymes in the phagosome or in peroxisomes generate strongly bactericidal reactive oxygen species … Superoxide (O2−) Hydrogen peroxide (H2O2) Hydroxyl ions (OH−) Myeloperoxidase catalyzes H2O2 + 2Cl− → … … → 2H+ + 2ClO− After entering the tissues, macrophages become fixed and may be resident for years. When appropriately stimulated they can break away and move to sites of inflammation. Circulating monocytes, mobile macrophages, fixed tissue macrophages, and some specialized endothelial cells form the reticuloendothelial system, almost all derived from monocytes. A phagocytic system is located in all tissues.

Answer 91

Skin, subcutaneous (histiocytes) Lymph nodes Ingest/sample particles arriving through the lymph Alveolar macrophages Digest or entrap inhaled particles and microorganisms Kupffer cells Surveillance of the portal circulation Macrophages in the spleen and bone marrow Surveillance of the general circulation

Answer 92

Inflammation is driven by chemical mediators and characterized by heat, redness, swelling, and pain. Physiologically, it involves … vasodilatation and increased blood flow. increased capillary permeability. coagulation of interstitial fluids. accumulation of granulocytes and monocytes. swelling of tissue cells. Mediators: histamine, bradykinin, serotonin, prostaglandins, complement products, clotting components, lymphokines

Answer 93

Fibrinogen clots minimize fluid flow in and out of the inflamed area. Staphylococci cause intense inflammation and are effectively “walled off.” Streptococci induce less intense inflammation and may be more likely to spread than staphylococci.

Answer 94

Tissue macrophages that encounter foreign particles enlarge and become mobile to provide a first line of defense. Within an hour neutrophils migrate to the area in response to inflammatory cytokines (TNF, IL-1). Upregulated selectins and ICAM-1 on endothelial cells are bound by integrins on neutrophils, leading to margination, followed by diapedesis, and chemotaxis directing neutrophils into the inflamed tissues, to kill bacteria and scavenge.

Answer 95

With intense inflammation neutrophil count … 4000–5000 → 15000–25000 Results from mobilization of mature neutrophils from the bone marrow by inflammatory mediators

Answer 96

Pus is composed of dead bacteria and neutrophils, many dead macrophages, necrotic tissue that has been degraded by proteases, and tissue fluid, often in a cavity formed at the inflammatory site. Over days and weeks it is absorbed into the surrounding tissue and lymph and disappears.

Answer 97

Eosinophils are weak phagocytes and exhibit chemotaxis. Particularly important in defense against parasites (schistosomiasis, trichinosis) Can adhere to parasites and release substances that kill them (hydrolases, reactive oxygen species, major basic protein) Also accumulate in tissues affected by allergies, perhaps in response to eosinophil chemotactic factor from basophils (eosinophils may detoxify some products of basophils)

Answer 98

Similar to mast cells adjacent to capillaries both cell types release heparin Basophils and mast cells both release histamine, bradykinin, and serotonin. When IgE bound to receptors on their surfaces is cross-linked by its specific antigen, mast cells and basophils degranulate, releasing … histamine, bradykinin, serotonin, heparin, leukotrienes, and several lysosomal enzymes

Answer 99

Leukopenia, or low white blood cell count, is usually the result of reduced production of cells by the bone marrow.

Answer 100

Innate = ability to resist damaging organisms and toxins: skin, gastric acids, tissue neutrophils and macrophages, complement, microbicidal and lytic chemicals in blood and blood cells Acquired = specific humoral → circulating antibodies cellular → activated cells

Answer 101

Antibodies or activated cells that specifically target and destroy invading organisms and toxins (Specificity) Powerful: can neutralize 100,000 × lethal dose of some toxins Two types of acquired immunity: Humoral (B cell ) B Lymphocytes Cell-mediated (T cell ) T Lymphocytes

Answer 102

A substance that can elicit an immune response Unique to each invading organism Usually proteins or large polysaccharides Most are large (MW > 8,000) and have recurring molecular groups on their surfaces The molecular structures that are specifically recognized in acquired immunity are called “epitopes.”

Answer 103

Mediate acquired immunity Develop in lymphoid tissues Tonsils/adenoids, Peyer’s patches (GI), lymph nodes, spleen, thymus, marrow Are strategically positioned

Answer 104

B Lymphocyte is involved in antibody production

Answer 105

Rapid expansion Each clone is specific for a single antigen. Self-reactive clones are deleted (up to 90%). Migrate to peripheral lymphoid organs Much of the above occurs just before and shortly after birth.

Answer 106

Initial growth and differentiation in the liver (fetal) and bone marrow (after birth) Migrate to the peripheral lymphoid organs Each clone is specific for a single antigen. *** Specific to what caused it*** Clonal development provides almost limitless antibody specificity. Secreted antibodies destroy or neutralize molecules or organisms bearing their cognate antigen.

Answer 107

Each B- or T-cell clone is specific for a single epitope of a single antigen. The genes for B-cell receptors (immuno-globulins) and T cell receptors have hundreds of “cassettes” that are used in varying combinations. Permutations of these cassettes allow specificity for millions of distinct epitopes.

Answer 108

B cells bind intact antigen T cells bind presented antigenic peptides B cells proliferate (with T cell help), developing lymphoblasts and plasmablasts Up to 500 antigen-specific progeny in 4 days, each producing as many as 2,000 Ig molecules/sec Can persist for many weeks, if antigenic stimulation persists

Answer 109

Each antibody has a steric configuration specific to its antigen. Two types of light chain - Kappa and lambda Name antibody based on the Heavy Chain IgM (earliest produced, five pairs of heavy chains and light chains) IgG (75% of all immunoglobulins)... produced at 2,3,4th reaction IgA... found in secretions IgD... appears to enhance mucosal homeostasis and immune surveillance IgE (critically involved in allergic reactions) Immunoglobulins make up about 20% of all plasma proteins. Involved with allergic reaction/hypersensitivity

Answer 110

Agglutination Precipitation - example rheumatoid arthritis, a reaction that occurs when soluble antigens and antibodies combine to form insoluble complexes, also known as precipitates Neutralization - the process by which antibodies prevent pathogens from binding to host cells. This process blocks the early stages of viral replication and prevents the pathogen from causing disease Lysis - destroys Complement activation

Answer 111

What we see when you mismatch blood = hemagglutination "Clumping"

Answer 112

Ultimate result is Lysis

Answer 113

Binds to cognate antigen presented by antigen-presenting cell Rapid expansion of T-helper (CD4) cells T-helper cells produce cytokines. Drives expansion of both T-helper (CD4) and cytotoxic (CD8) T cells Both types of cells also generate clonal memory T cells.

Answer 114

~ 75% of all T cells Regulate functions of other immunologic cells by producing cytokines … Interleukin (IL-) 2, 3, 4, 5, 6, GM-CSF, Interferon-gamma What HIV kills

Answer 115

They recognize the change in the cell by the 3 reasons on picture... so they destroy the cell

Answer 116

Tolerance = we tolerate our cells, we recognize our own cells “Tolerance” in acquired immunity is achieved mainly by clonal selection of T cells in the thymus and B cells in the bone marrow. Clones that bind host antigens with high affinity are induced to undergo apoptosis, and are deleted. Failure of Tolerance Produces Autoimmunity Rheumatic fever (cross-reactivity with streptococcal antigens) Poststreptococcal glomerulonephritis Myasthenia gravis (antibodies to acetylcholine receptors) Systemic lupus erythematosus (auto-immunity to multiple tissues)

Answer 117

Injecting killed organisms or their products … Typhoid, whooping cough, diphtheria, tetanus toxoid Infection with attenuated organisms … Smallpox, yellow fever, polio, measles, herpes zoster, other viral diseases Passive immunity … Infusing antibody or activated T cells from an immune individual (antibodies last 2–3 weeks) Natural Active - exposed to people out in public and body does the work Natural Passive - Mother gave it to you with breast milk, given the immunoglobin Artificial Active - Vaccine Artificial Passive - Given the immunity, given the immunoglobins in a non-natural way, ex. rabies vaccine

Answer 118

Patient has to be sensitized with the antibody the first time, its not the first bee sting... it was the IgE antibodies that were developed the first time... so when come in contact 2nd time, Mast Cells release histamine and others T cell mediated (delayed) … poison ivy, nickel allergies. usually cutaneous; can occur in lungs with airborne antigens. IgE mediated (immediate) … typical allergies. a single mast cell/basophil can bind 500,000 IgE molecules.

Answer 119

Histamine Proteases Leukotrienes Eosinophil and neutrophil chemotactic factors Heparin Platelet activating factor

Answer 120

Afferent nerves go right to medulla (thalamus)

Answer 121

Vitamin B12 is needed for final step to make RBCs

Answer 122

Blood starts clotting by platelets... initiated by collagen

Answer 123

Antibody A - is the passive immunity from a mother

2025 Physiology Exam 2 Flashcards

Lectures 6-11: Cardiovascular, Vascular and Lymphatics, Chemical Senses, Cardiovascular Physiology