Unit 1: Ch 18, 19, 20 Flashcards

Question

Eosinophils

Answer 1

* Type of granulocyte * Increased numbers in _parasitic_ infections, collagen diseases, allergies, diseases of spleen and CNS * Phagocytosis of antigen–antibody complexes, allergens, and inflammatory chemicals * Release enzymes to destroy large parasites

Answer 2

* RBCs & macrophages in spleen * Separate heme from globin * Globins hydrolyzed into amino acids * Iron removed from heme * _Heme_ pigment converted to _biliverdin_ (green) * _Biliverdin_ converted to _bilirubin_ (yellow) * Released into _blood plasma_ (kidneys—yellow urine) * Liver removes bilirubin and secretes into bile * Concentrated in gallbladder: released into small intestine; bacteria create urobilinogen (brown feces)

Answer 3

* Imbalance between the rates of erythropoiesis and RBC destruction * Types * _Polycythemia_: RBC excess * _Anemia_: RBC or hemoglobin deficiency

Answer 4

* Carry oxygen from the lungs and deliver it to tissues * Pick up CO₂ from tissues and bring to lungs

Answer 5

* Disc-shaped cell with thick rim * Most abundant formed elements of the blood and most critical to survival * It is the lack of life-giving oxygen, carried by erythrocytes, that leads rapidly to death in cases of major trauma * The only human cells that carry on _anaerobic fermentation_ indefinitely * Lose nearly all organelles during development * _Lack mitochondria_; rely exclusively on anaerobic fermentation to produce ATP * _Lack of nucleus and DNA_; no protein synthesis or mitosis

Answer 6

* Becomes fibrin, the major component of blood clots

Answer 7

* Erythrocytes (RBC) * Platelets * Leukocytes (WBC) * _Granulocytes_ (with granules) * Basophils * Eosinophils * Neutrophils * _Agranulocytes_ (without granules) * Lymphocytes * Monocytes

Answer 8

* Fractionation of blood into formed elements, plasma, and serum

Answer 9

* The percentage by volume of red cells in your blood * Packed cell volume

Answer 10

* The study of blood

Answer 11

* Masses of clotted blood in the tissues * _Thrombosis_: Abnormal clotting in unbroken vessel * _Thrombus_: Clot most likely to occur in leg veins of inactive people

Answer 12

* The production of blood, especially its formed elements

Answer 13

* Differentiate into distinct types of _colony-forming units (CFU)_ and then produce the following cell lines, each committed to a certain outcome * _Myeloblasts_: differentiate into 3 types of granulocytes * basophils * eosinophils * neutrophils * _Monoblasts_: lead ultimately to monocytes * _Lymphoblasts_: produce all lymphocyte types

Answer 14

1. Heme → Biliverdin → Bilirubin → Bile → Feces 2. Heme → Iron → Storage → Reuse 3. Heme → Iron → Reuse 4. Heme → Iron → Loss by menstruation, injury, etc 5. Globin → Hydrolyzed to free amino acids

Answer 15

* Rupture of RBCs * Releases hemoglobin and leaves empty plasma membranes * Membrane fragments digested by macrophages in the liver and spleen

Answer 16

* Can occur when a woman has a baby with a mismatched blood type, typically when she is Rh- and carries an Rh+ fetus * Causes * Mismatched Rh type (most severe) * Mismatched ABO type * Mismatched Kell blood group * Mismatched Kidd * Mismatched Duffy

Answer 17

* A family of hereditary diseases characterized by deficiencies of one factor or another * Occurs predominantly in males * Can inherit it only from mothers * Types * _Classical hemophilia (hemophilia A)_: Lack of factor VIII * _Hemophilia B_: Lack of factor IX * _Hemophilia C_: Lack of factor XI; autosomal and not sex-linked - occurs equally in both sexes

Answer 18

The cessation of bleeding

Answer 19

* **Vascular spasm** * Immediate protection against blood loss * Constriction of broken blood vessels * **Platelet plug formation** * Mass of formed platelets * **Blood clotting (coagulation)** * The last but most effective defense against bleeding * Converts fibrinogen into fibrin * 2 reaction pathways * _Extrinsic mechanism_: initiated by clotting factors released by the damaged blood vessel and perivascular tissues. Come from sources external to the blood itself * _Intrinsic mechanism:_ Uses only clotting factors found in the blood itself

Answer 20

* "Starvation" / deficiency of plasma proteins * extreme starvation * liver or kidney disease * severe burns

Answer 21

* Oxygen deficiency in the blood * Causes * Blood loss * Low levels of oxygen in the atmosphere * Abrupt increase in the body's oxygen consumption

Answer 22

* Infection of B _lymphocytes_ with Epstein-Barr virus

Answer 23

* Syndrome of toxic brain damage that can be lethal or leave the child with motor, sensory, and mental deficiencies * Caused by HDN; high bilirubin levels * Treatments * _Phototherapy_: exposes the infant to ultraviolet radiation * _Exchange transfusion_: completely replaces an infant's Rh+ blood with Rh-

Answer 24

* Children with severe plasma protein deficiency * Thin arms and legs * Swollen abdomen * Fed on cereals once weaned

Answer 25

* **Acute leukemia** * Appears suddenly, progresses rapidly, and causes death if untreated * **Chronic leukemia** * Develops more slowly and may go undetected * If untreated, the typical survival time is 3 yrs * **Lymphoid leukemia** * Uncontrolled lymphocyte or monocyte production * **Myeloid leukemia** * Uncontrolled granulocyte production

Answer 26

1. **Leukocytosis**—high WBC count: above 10,000 WBCs/mL * Causes: infection, allergy, disease * Differential WBC count: identifies what percentage of the total WBC count consist of each type of leukocyte 2. **Leukemia**—cancer of hemopoietic tissue that usually produces an extraordinary high number of circulating leukocytes and their precursors * Effects: normal cell percentages disrupted; impaired clotting; opportunistic infections 3. **Leukopenia**—low WBC count: below 5,000 WBCs/mL * Causes: radiation, poisons, infectious disease * Effects: elevated risk of infection

Answer 27

* Least abundant formed elements * Protect against infection & other diseases * Differ from RBCs in that they retain their organelles throughout their life * Conspicuous nucleus * Retain their organelles for protein synthesis

Answer 28

* Type of agranulocyte * Function * Destroy cells (cancer, foreign, and virally infected cells) * “Present” antigens to activate other immune cells * Secrete antibodies and provide _immune memory_ * Increased numbers in diverse infections and immune responses

Answer 29

* Type of agranulocyte * Increased numbers in _viral infections_ and _inflammation_ * Leave bloodstream and transform into macrophages * Phagocytize pathogens and debris * “Present” antigens to activate other immune cells—antigen-presenting cells (APCs)

Answer 30

* Blood formation in the bone marrow

Answer 31

* Type of granulocyte * Increased numbers in _bacterial_ infections * Phagocytosis of bacteria * Release antimicrobial chemicals

Answer 32

* The establishment of pathogenic organisms that usually cannot get a foothold in people with healthy immune systems * Caused by the deficiency of competent WBCs

Answer 33

* The total molarity of dissolved particles that cannot pass through the blood vessel wall * _If too high_: blood absorbs too much water, increasing the blood pressure * _If too low_: too much water stays in tissue, blood pressure drops, and edema occurs * Optimum osmolarity is achieved by the body's regulation of sodium ions, proteins, and RBCs

Answer 34

* Rarely cause transfusion reactions * Useful for legal purposes (paternity) and criminal cases * Now that DNA sequencing is more economical, it has replaced blood typing in many applications * Types * Duffy * Kell * Kidd * Lewis * MNS

Answer 35

* Clotting * Defense against pathogens * Transport of other solutes such as iron, copper, lipids, and hydrophobic hormones

Answer 36

* Formed by liver, except globulins which are produced by plasma cells * Categories 1. Albumins * smallest and most abundant * contribute to visosity and osmolarity * influence blood pressure, flow and fluid balance 2. Globulins * antibodies * provide immune system functions * alpha, beta, and gamma globulins 3. Fibinogen * precursor of fibrin threads that help form blood clots

Answer 37

* Initiate the formation of a clot-dissolving enzyme * Secrete vasoconstrictors * Internalize and destroy bacteria

Answer 38

* **Thrombopoiesis** * Stem cells (that develop receptors for thrombopoietin) become megakaryoblasts * **Megakaryoblasts** * Repeatedly replicate DNA without dividing * **Megakaryocytes**

Answer 39

* When a blood clot breaks free and travels from veins to lungs

Answer 40

* Androgens stimulate RBC production, and men have higher androgen levels than women * Women of reproductive age have periodic menstrual losses * The hematocrit is inversely proportional to % of body fat, which average higher in women

Answer 41

* Produces all 7 formed elements

Answer 42

* Description * Named for the rhesus monkey * ABO blood type has no influence on Rh type * Occurs if Rh- mother has formed antibodies and is pregnant with second Rh+ child * Anti-D antibodies can cross placenta * Prevention * RhoGAM given to pregnant Rh- women * Binds fetal agglutinogens in her blood so she will not form anti-D antibodies * Antigens * Principal RBC antigen types are C, D, and E * Antigen D is the most reactive * Determination * Rh+ if a person has antigen D * Rh- if someone does not have antigen D

Answer 43

* Hereditary hemoglobin defects that occur mostly among people of African descent * Caused by a recessive allele that modifies the structure of the hemoglobin molecule (HbS) * Differs only on the sixth amino acid of the beta chain * HbS does not bind oxygen well * RBCs become rigid, sticky, pointed at ends * Clump together and block small blood vessels causing intense pain * Can lead to kidney or heart failure, stroke, rheumatism, or paralysis

Answer 44

* Hereditary anemias most common in Greeks, Italians, and others of Mediterranean descent * Deficiency or absence of alpha or beta hemoglobin and RBC counts that may be less than 2 million

Answer 45

* Platelet counts below 100k * Causes include bone marrow destruction by radiation, drugs, poisons, or leukemia * Signs include small hemorrhagic spots in the skin or hematomas in response to minor trauma

Answer 46

* Universal donor * Type O: most common blood type * Lacks RBC antigens * Donor’s plasma may have both antibodies against recipient’s RBCs (anti-A and anti-B) * May give packed cells (minimal plasma) * Universal recipient * Type AB: rarest blood type * Lacks plasma antibodies; no anti-A or anti-B

Answer 47

* Heart * Blood vessels

Answer 48

* Heart * Blood vessels * Blood

Answer 49

* **Pulmonary circuit** * Right side of heart * Carries blood to lungs for gas exchange and back to heart * Lesser oxygenated blood arrives from inferior and superior venae cavae * Blood sent to lungs via pulmonary trunk * **Systemic circuit** * Left side of heart * Supplies oxygenated blood to all tissues of the body and returns it to the heart * Fully oxygenated blood arrives from lungs via pulmonary veins * Blood sent to all organs of the body via aorta

Answer 50

* **Base** * Wide, superior portion of heart * Blood vessels attach here * **Apex** * Inferior end * Tilts to the left, tapers to point

Answer 51

* Double-walled sac (pericardial sac) that encloses the heart * Allows heart to beat without friction, provides room to expand, yet resists excessive expansion * Anchored to diaphragm inferiorly and sternum anteriorly

Answer 52

* Outer wall of sac * Superficial fibrous layer of connective tissue * Deep, thin serous layer

Answer 53

* Heart covering * Serous lining of sac turns inward at base of heart to cover the heart surface * Adipose in thick layer in some places * Coronary blood vessels travel through this layer

Answer 54

* Space inside the pericardial sac filled with 5 to 30 mL of pericardial fluid

Answer 55

* Inflammation of the membranes * Painful friction rub with each heartbeat

Answer 56

* Smooth inner lining of heart and blood vessels * Covers the valve surfaces and is continuous with endothelium of blood vessels

Answer 57

* Layer of cardiac muscle proportional to work load * Muscle spirals around heart which produces wringing motion

Answer 58

* **Right and left atria** * Two superior chambers * Receive blood returning to heart * Auricles (seen on surface) enlarge chamber * **Right and left ventricles** * Two inferior chambers * Pump blood into arteries

Answer 59

* Separates atria and ventricles

Answer 60

* Overlies the interventricular septum that divides the right ventricle from the left

Answer 61

* Receives oxygen poor blood **from body** * Filling chamber

Answer 62

* Pumps blood **to lungs** to get oxygen and get rid of CO₂

Answer 63

* Receives oxygen rich blood from lungs * Filling station

Answer 64

* Pumps oxygen rich blood **to the entire body**

Answer 65

* Control blood flow between atria and ventricles * Right AV valve has three cusps (tricuspid valve) * Left AV valve has two cusps (mitral or bicuspid valve)

Answer 66

* Control flow into great arteries; open and close because of blood flow and pressure * **Pulmonary semilunar valve**: an opening between right ventricle and pulmonary trunk * **Aortic semilunar valve**: an opening between left ventricle and aorta

Answer 67

1. Blood enters right atrium from superior and inferior venae cavae 2. Blood in right atrium flows through right AV valve into right ventricle 3. Contraction of right ventricle forces pulmonary valve open 4. Blood flows through pulmonary valve into pulmonary trunk 5. Blood is distributed by right and left pulmonary arteries to the lungs, where it unloads CO2 and loads O2 6. Blood returns from lungs via pulmonary veins to left atrium 7. Blood in left atrium flows through left AV valve into left ventricle 8. Contraction of left ventricle (simultaneous with step 3) forces aortic valve open 9. Blood flows through aortic valve into ascending aorta 10. Blood in aorta is distributed to every organ in the body, where it unloads O₂ and loads CO₂ 11. Blood returns to the heart via venae cavae

Answer 68

* **Ascending** aorta

Answer 69

* Structure of the cardiac muscle * Striated, short, thick, branched cells * One central nucleus surrounded by light-staining mass of glycogen

Answer 70

* Coordinates the heartbeat * Composed of an internal pacemaker and nervelike conduction pathways through myocardium * Nodes (in order of ventricular filling) 1. Sinoatrial (SA) node 2. Atrioventricular (AV) node 3. Atrioventricular (AV) bundle 4. Purkinje fibers

Answer 71

1. _SA node_ fires 2. Excitation spreads through _atrial myocardium_ 3. _AV node_ fires 4. Excitation spreads down _AV bundle_ 5. _Purkinje fibers_ distribute excitation through _ventricular myocardium_

Answer 72

1. **Sympathetic nerves:** raises heart rate 2. **Parasympathetic nerves:** slows heart rate

Answer 73

* **Systole:** atrial or ventricular contraction * **Diastole:** atrial or ventricular relaxation * **Systole / diastole = blood pressure**

Answer 74

* Sinus rhythm * Ectopic rhythm * Ectopic foci * Arrhythmia

Answer 75

* One complete contraction and relaxation of all four chambers of the heart * Cycle components * Diastole (relaxation) * Occurs while ventricles in systole * Systole (contraction) * Occurs while ventricles are in diastole * Quiescent period * * ****When all four chambers relaxed at same time

Answer 76

1. **Pressure** _causes_ a fluid to flow (fluid dynamics) * Pressure gradient—pressure difference between two points * Measured in _mm Hg_ with a _manometer_ or _sphygmomanometer_ 2. **Resistance** _opposes_ fluid flow

Answer 77

* Any failure of a valve to prevent reflux, the backward flow of blood 1. Valvular stenosis 2. Mitral valve prolapse

Answer 78

* **S1** * First heart sound * Louder and longer “lubb” * Occurs with closure of AV valves, turbulence in the bloodstream, and movements of the heart wall * **S2** * Second heart sound * Softer and sharper “dupp” * Occurs with closure of semilunar valves, turbulence in the bloodstream, and movements of the heart wall * **S3** * Rarely heard in people over 30

Answer 79

1. Rapid ventricular filling * First one-third * Blood enters very quickly 2. Diastasis * Second one-third * Marked by slower filling * P wave occurs at the end of diastasis 3. Systole * Final one-third * Atria contract

Answer 80

* **Pulmonary edema** * When the left ventricle pumps less blood than the right, and blood pressure backs up into the lungs * **Systemic edema** * When the right ventricle pumps less blood than the left, and pressure backs up in the systemic circulation * The side that is working too hard is the side that will have fluid accumulation

Answer 81

* Results from the failure of either ventricle to eject blood effectively

Answer 82

* Occurs when blood backs up into the _lungs_ causing _pulmonary edema_ * Shortness of breath or sense of suffocation * Eventually leads to total heart failure

Answer 83

The amount of blood ejected by the ventricles in 1 minute

Answer 84

* Surge of pressure produced by each heart beat * Can be felt by palpating a superficial artery with the fingertips * Never use thumb to take pulse because it has it’s own heart rate

Answer 85

* Resting adult heart rate above 100 bpm * Stress, anxiety, drugs, heart disease, or fever * Loss of blood or damage to myocardium

Answer 86

* Resting adult heart rate of less than 60 bpm * In sleep, low body temperature, and endurance-trained athletes

Answer 87

* Cardiac centers in the reticular formation of the _medulla oblongata_ initiate autonomic output to the heart * ANS does not initiate the heartbeat, it modulates rhythm and force

Answer 88

1. Preload 2. Contractility 3. Afterload

Answer 89

* A constriction of the coronary arteries * Usually the result of _atherosclerosis_ * An accumulation of lipid deposits that degrade the arterial wall and obstruct the lumen * Endothelium damaged by hypertension, virus, diabetes, or other causes

Answer 90

1. Atrioventricular valves open → atrioventricular valves close 2. Semilunar valves open → semilunar valves close

Answer 91

* Cords that connect AV valves to papillary muscles on floor of ventricles * Prevent AV valves from flipping inside out or bulging into the atria when the ventricles contract

Answer 92

* A part of the conduction system * Pacemaker initiates each heartbeat and determines heart rate * Pacemaker in right atrium near base of superior vena cava

Answer 93

1. Pathway begins with _nuclei of the vagus nerves in the medulla oblongata_ (X cranial nerves) * Supplies the heart, lungs, upper digestive tract, and other organs of the chest and abdomen 2. Fibers of _right vagus_ nerve lead to the _SA node_ 3. Fibers of _left vagus nerve_ lead to the _AV node_ 4. Little or no vagal stimulation of the myocardium

Answer 94

Normal heartbeat triggered by the SA node

Answer 95

* Another part of the heart that fires before the SA node

Answer 96

* Occur when myocardial cells located outside the SA node take over the normal pacemaker function of the SA node by becoming unusually “automatic” * _Nodal rhythm_ * If SA node is damaged, heart rate is set by AV node, 40 to 50 bpm * _Intrinsic ventricular rhythm_ * If both SA and AV nodes are not functioning, rate set at 20 to 40 bpm * Requires pacemaker to sustain life

Answer 97

* Any abnormal cardiac rhythm * Failure of conduction system to transmit signals (heart block) * Types of heart blocks: * Bundle branch block * Total heart block (damage to AV node)

Answer 98

* Cusps are stiffened and opening is constricted by scar tissue * Result of rheumatic fever, autoimmune attack on the mitral and aortic valves * Heart overworks and may become enlarged

Answer 99

* Insufficiency in which one or both mitral valve cusps bulge into atria during ventricular contraction * Hereditary in 1 out of 40 people * May cause chest pain and shortness of breath * Which side of the heart will this be an issue? The systemic or pulmonary? * Whichever side of the heart the pulmonary valve is on is the side that has the problem with prolapse

Answer 100

* A part of the conduction system * Bundle forks into right and left bundle branches * Branches pass through interventricular septum toward apex

Answer 101

* A part of the conduction system * Nervelike processes that spread throughout ventricular myocardium * Signal passes from cell to cell through gap junctions

Answer 102

* A part of the conduction system * Electrical gateway to the ventricles * Located near the right AV valve at lower end of interatrial septum * Fibrous skeleton—insulator prevents currents from getting to ventricles from any other route

Answer 103

* Occurs when blood backs up in the _vena cava_ causing _systemic or generalized edema_ * Enlargement of the liver, ascites (pooling of fluid in abdominal cavity), distension of jugular veins, swelling of the fingers, ankles, and feet * Eventually leads to total heart failure

Answer 104

Abnormal heart sound produced by regurgitation of blood through incompetent valves

Answer 105

* Carry blood away from the heart * 99% carry oxygenated blood. The exception is the pulmonary artery/trunk

Answer 106

* Carry blood back to the heart * 99% carry deoxygenated blood. Exception is the pulmonary vein

Answer 107

1. **Tunica interna**: lines the blood vessel and is exposed to blood 2. **Tunic media**: middle layer 3. **Tunica externa**: outermost layer

Answer 108

* **Conducting arteries** (elastic or large arteries) * Biggest arteries * Examples: aorta, common carotid, subclavian, pulmonary trunk, common iliac arteries * **Distributing** (muscular or medium) arteries * Distributes blood to _specific_ organs * Examples: brachial, femoral, renal, splenic * **Resistance** (small) arteries * Smallest arteries * Control amount of blood to various organs * **Metarterioles** * Short vessels that link arterioles to capillaries * Examples: muscle cells from a precapillary sphincter about entrance to capillary

Answer 109

* Weak point in an artery or the heart wall * Forms a thin-walled, _bulging sac_ that pulsates with each heartbeat and may rupture at any time * Common sites * Abdominal aorta * Renal arteries * Arterial circle at base of brain * Common cause is _atherosclerosis_ and _hypertension_

Answer 110

* *Middle man* between an artery and vein * Distinguished by ease with which substances pass through their walls and by structural differences that account for their greater or lesser permeability * Types 1. **Continuous capillaries** * Occur in most tissues 2. **Fenestrated capillaries** * Organs that require rapid absorption or filtration * kidneys, small intestine 3. **Sinusoids (discontinuous capillaries)** * Irregular blood-filled spaces with large fenestrations * liver, bone marrow, spleen

Answer 111

* Capillaries are organized into networks * Precapillary sphincters * Control which beds are well _perfused_ * When sphincters open: * Capillaries are well perfused with blood and engage in exchanges with the tissue fluid * When sphincters closed: * Blood bypasses the capillaries * Flows through thoroughfare channel * **3/4 of the body’s capillaries are shut down at a given time**

Answer 112

1. **Postcapillary venules:** smallest veins 2. **Muscular venules:** up to 1 mm in diameter 3. **Medium veins:** up to 10 mm in diameter 4. **Venous sinuses**: Not capable of vasomotion 5. **Large veins:** larger than 10 mm * Contains longitudinal bundles of smooth muscle * Venae cavae, pulmonary veins, internal jugular veins, and renal veins

Answer 113

* Occur when valves in veins stop working * Hemorrhoids are varicose veins of the anal canal

Answer 114

* Simplest and most common route * Portal system * Anastomosis * Arterial anastomosis * Venous anastomosis (most common) * Arteriovenous anastomosis (shunt)

Answer 115

* **Blood flow**: the amount of blood flowing through an organ, tissue, or blood vessel in a given time (mL/min) * **Perfusion**: the flow per given _volume or mass of tissue_ in a given time (mL/min./g) * At rest, total flow is quite constant, and is equal to the cardiac output (5.25 L/min)

Answer 116

* The force that blood exerts against a vessel wall * Measured at _brachial artery_ of arm using _sphygmomanometer_ * Two pressures are recorded * **Systolic pressure**: peak arterial BP taken during ventricular contraction (ventricular systole) * **Diastolic pressure**: minimum arterial BP taken during ventricular relaxation (diastole) between heart beats

Answer 117

* High blood pressure that can weaken small arteries and cause aneurysms * Chronic hyptertension is resting BP \> 140/90

Answer 118

* Chronic low resting BP \< 90/60 * Caused by blood loss, dehydration, anemia

Answer 119

* BP is always higher in arteries closer to heart than in arteries farther away from the heart

Answer 120

* Opposition to flow that blood encounters in vessels away from the heart * 3 variables 1. **Blood viscosity** (thickness) 2. **Vessel length** * Pressure and flow decline with distance 3. **Vessel radius**: most powerful influence over flow * Only significant way of controlling peripheral resistance * _Vasoconstriction_: by muscular effort that results in smooth muscle contraction * _Vasodilation_: by relaxation of the smooth muscle

Answer 121

* Velocity _decreases_ * 3 reasons 1. Greater distance, more friction to reduce speed 2. Smaller radii of arterioles and capillaries offers more resistance 3. Farther from heart, the number of vessels and their total cross-sectional area become greater and greater

Answer 122

* Flow _increases_ * Reasons * Decreased resistance going from capillaries to veins * Large amount of blood forced into smaller channels * Never regains velocity of large arteries

Answer 123

* Altering blood pressure and flow via change in vessel radius * 3 ways of controlling vasomotion * Local control * Neural control * Hormonal control

Answer 124

* A form of controlling vasomotion * Local control types * Angiogenesis * Autoregulation * Reactive hyperemia * Vasoactive chemicals

Answer 125

* A form of controlling vasomotion * Primary role * Adjust respiration to changes in blood chemistry * Under remote control by the CNS & ANS * Secondary role * Vasomotion * Vasomotor center of medulla oblongata exerts _sympathetic control_ over blood vessels * Precapillary sphincters respond only to local and hormonal control due to lack of innervation * Integrating center for 3 autonomic reflexes * Baroreflexes * Chemoreflexes * Medullary ischemic reflex

Answer 126

* The point where two blood vessels merge

Answer 127

* A form of controlling vasomotion * Hormones influence blood pressure * How? * Vasoactive effects * Regulating water balance

Answer 128

* A form of hormonal control * _Vasoconstriction_ * Epinephrine * __Bind to a-adrenergic receptors * Most blood vessels * _Vasodilation_ * Norepinephrine * Bind to b-adrenergic receptors * Skeletal and cardiac muscle blood vessels

Answer 129

* Arterioles shift blood flow with changing priorities * During exercise * Increased perfusion of lungs, myocardium, and skeletal muscles * Decreased perfusion of kidneys and digestive tract

Answer 130

* Two-way movement of fluid across capillary walls * Chemicals pass through via 3 routes 1. Endothelial cell cytoplasm 2. Intercellular clefts between endothelial cells 3. Filtration pores (fenestrations) of the fenestrated capillaries * Mechanisms * Diffusion * Filtration * Reabsorption * Transcytosis

Answer 131

* The most important form of capillary exchange * Glucose and oxygen diffuse out of the blood * CO₂and other waste diffuse into the blood * Conditions required to occur * The solute can permeate the plasma membranes of the endothelial cell; or * Find passages large enough to pass through * Filtration pores and intracellular clefts

Answer 132

* Endothelial cells pick up material on one side of the plasma membrane by pinocytosis (cell-drinking, fluid endocytosis) or receptor-mediated endocytosis, transport vesicles across cell, and discharge material on other side by exocytosis * Important for fatty acids, albumin, and some hormones (insulin)

Answer 133

* Fluid filters out of the arterial end of the capillary and osmotically reenters at the venous end * Opposing forces 1. **Blood hydrostatic pressure drives fluid out of capillary** * High on arterial end of capillary, low on venous end 2. **Colloid osmotic pressure (COP) draws fluid into capillary** * Oncotic pressure = net COP (blood COP − tissue COP) 3. **Hydrostatic pressure** * Physical force exerted against a surface by a liquid * *Capillaries reabsorb about 85% of the fluid they filter* * *Other 15% is absorbed by the _lymphatic_ system and returned to the blood*

Answer 134

* The accumulation of excess fluid in a tissue * Occurs when fluid filters into a tissue faster than it is absorbed * 3 primary causes 1. Increased capillary filtration * Kidney failure, histamine release, old age, poor venous return 2. Reduced capillary absorption * Hypoproteinemia, liver disease, dietary protein deficiency 3. Obstructed lymphatic drainage * Surgical removal of lymph nodes

Answer 135

* **Cerebral edema** * Headaches, nausea, seizures, and coma * **Pulmonary edema** * Suffocation threat * **Severe edema or circulatory shock** * Excess fluid in tissue spaces causes low blood volume and low blood pressure * **Tissue necrosis** * Oxygen delivery and waste removal impaired

Answer 136

* The flow of blood back to the heart * Mechanisms 1. Pressure gradient * Blood pressure is the most important force in venous return * 7 to 13 mm Hg venous pressure toward heart * Venules (12 to 18 mm Hg) to central venous pressure: point where the venae cavae enter the heart (~5 mm Hg) 2. Gravity drains blood from head and neck 3. Skeletal muscle pump in the limbs * Contracting muscle squeezed out of the compressed part of the vein 4. Thoracic (respiratory) pump * Inhalation—thoracic cavity expands and thoracic pressure decreases, abdominal pressure increases forcing blood upward * Central venous pressure fluctuates * Blood flows faster with inhalation 5. Cardiac suction of expanding atrial space

Answer 137

* Exercise increases venous return in many ways * Heart beats faster and harder, increasing CO and BP * Vessels of skeletal muscles, lungs, and heart dilate and increase flow * Increased respiratory rate, increased action of thoracic pump * Increased skeletal muscle pump * Venous pooling occurs with inactivity * Venous pressure not enough to force blood upward * With prolonged standing, CO may be low enough to cause dizziness * Prevented by tensing leg muscles, activate skeletal muscle pump * Jet pilots wear pressure suits

Answer 138

* When cardiac output is insufficient to meet the body’s metabolic needs

Answer 139

1. **Hypovolemic shock (most common)** * Loss of blood volume: trauma, burns, dehydration 2. **Obstructed venous return shock** * Tumor or aneurysm compresses a vein 3. **Venous pooling (vascular) shock** * Long periods of standing, sitting, or widespread vasodilation

Answer 140

* **Anaphylactic shock** * Severe immune reaction to antigen, histamine release, generalized vasodilation, increased capillary permeability * **Cardiogenic shock** * Inadequate pumping of heart (MI) * **Low Venous Return (LVR)** * Too little blood is returning to the heart * **Neurogenic shock** * Loss of vasomotor tone, vasodilation * Multiple causes from emotional shock to brainstem injury * **Septic shock** * Bacterial toxins trigger vasodilation and increased capillary permeability

Answer 141

* **Compensated shock** * Several homeostatic mechanisms bring about spontaneous recovery * Example: If a person faints and falls to a horizontal position, gravity restores blood flow to the brain * **Decompensated shock** * Triggers when the compensated shock mechanism fails * Life-threatening positive feedback loops occur * Condition gets worse causing damage to cardiac and brain tissue

Answer 142

* Regulates its own blood flow to match changes in BP and chemistry * Main chemical stimulus: pH * _Hypercapnia_ * __CO₂ levels increase in brain * Decreases pH, triggers vasodilation * _Hypocapnia_ * Raises pH, stimulates vasoconstriction * Occurs with hyperventilation, may lead to ischemia, dizziness, and sometimes syncope

Answer 143

* Brief episodes of cerebral ischemia * Caused by spasms of diseased cerebral arteries * Dizziness, loss of vision, weakness, paralysis, headache, or aphasia * Lasts from a moment to a few hours * Often early warning of impending stroke

Answer 144

* Sudden death of brain tissue caused by ischemia * Atherosclerosis, thrombosis, ruptured aneurysm * Effects range from unnoticeable to fatal * Blindness, paralysis, loss of sensation, loss of speech common * Recovery depends on surrounding neurons, collateral circulation

Answer 145

* Large, thin-walled dural sinuses form between layers of dura mater * Drain blood from brain to internal jugular vein * **Internal jugular vein receives most of the blood from the brain** * Branches of external jugular vein drain the external structures of the head * Upper limb is drained by subclavian vein

Answer 146

Brachial artery

Answer 147

Radial artery

Answer 148

* Branches to the lower limb arise from _external iliac branch_ of the _common iliac_ artery

Answer 149

* Most common cardiovascular disease affecting about 30% of Americans over 50 * The silent killer * Major cause of heart failure, stroke, and kidney failure * Damages heart by increasing afterload * Myocardium enlarges until overstretched and inefficient * Renal arterioles thicken in response to stress * Drop in renal BP leads to salt retention (aldosterone) and worsens the overall hypertension * Types * Primary hypertension * Obesity, sedentary behavior, diet, nicotine * Secondary hypertension * Secondary to other disease * Kidney disease, hyperthyroidism

Answer 150

* Heart → arteries → arterioles → capillaries → venules → veins

Answer 151

* Blood flows through two consecutive capillary networks before returning to heart

Answer 152

* Artery flows directly into vein by passing capillaries

Answer 153

* One vein empties directly into another

Answer 154

* Two arteries merge

Answer 155

* Occurs when blood accumulates between the tunics of the artery and separates them * Usually due to the degeneration of the tunica media

Answer 156

* Form of local control * Growth of new blood vessels * Occurs in regrowth of uterine lining, around coronary artery obstructions, in exercised muscle, and malignant tumors * Controlled by growth factors

Answer 157

* Form of local control * If blood supply is cut off and then restored, blood flow increases above normal

Answer 158

* Form of local control * Substances secreted by platelets, endothelial cells, and perivascular tissue to stimulate vasomotion

Answer 159

* Form of local control * The ability of tissues to regulate their own blood supply

Answer 160

* A form of neural control * An automatic, negative feedback response to changes in blood pressure * Important in short-term regulation of BP but not in cases of chronic hypertension

Answer 161

* A form of neural control * An automatic response to changes in blood chemistry * Especially pH, and concentrations of O₂ and CO₂

Answer 162

* A form of neural control * Automatic response to a _drop in perfusion_ of the brain * Activates corrective reflexes when it senses ischemia (insufficient perfusion) * Cardiac and vasomotor centers send sympathetic signals to heart and blood vessels * Increases heart rate and contraction force * Widespread vasoconstriction * Raises BP and restores normal perfusion to the brain

Unit 1: Ch 18, 19, 20 Flashcards

(189 cards)