ch 7 - The Cardiovascular System

Question 1

pathway of blood

Answer 1

deoxygenated blood into R atrium (past tricuspid valve) to right ventricle past pulmonary valve to pulmonary artery to lungs to be oxygenated to pulmonary veins to left atrium past mitral valve to left ventricle past aortic valve to aorta to arteries to arterioles to capillaries (systemic body) to venules to veins to venae cavae to right atrium (which is deoxygenated blood)

Question 2

pulmonary circulation

Answer 2

first pump of heart, deoxygenated blood from body enters lungs from R side of heart

Question 3

systemic circulation

Answer 3

second pump of heart; receives oxygenated blood from lungs into L side and pumps it to body through aorta

Question 4

atrioventricular valves

Answer 4

atria are separated from ventricles by these

Question 5

semilunar valves

Answer 5

separate atrioventricular valves and vasculature; allow creation of pressure within the ventricles necessary to propel blood forward and prevent backflow

Question 6

tricuspid valve

Answer 6

valve between the right atrium and right venticle

Question 7

tricuspid or mitral valve

Answer 7

valve between the left atrium and left ventricle

Question 8

pulmonary valve

Answer 8

valve that separates right ventricle from pulmonary circulation

Question 9

aortic valve

Answer 9

valve that separates left ventricle from aorta

Question 10

pathway of electrical impulse in the heart

Answer 10

sinoatrial (SA) node, the atrioventricular (AV) node, the bundle of His (AV bundle) and its branches, and the Pukinje fibers

Question 11

SA node

Answer 11

small collection of cells located in the wall of the right atrium; sight of impulse initiation in heart; generates 60-100 signals per minute w/o requiring neurological input. depolarization wave spreads from SA node, causes two atria to contract simultaneously resulting in an atrial kick (extra bit of blood forced into the ventricles through atrial systole (contraction) - accounts for 5-30% of cardiac output)

Question 12

AV node

Answer 12

group of cells at junction of the atria and ventricles where electrical signal goes after SA node. Signal is delayed here to allow for ventricles to fill completely before they contract

Question 13

bundle of His and branches

Answer 13

in electrical signal pathway of heart after AV node; embedded in interventricular septum (wall)

Question 14

Purkinje fibers

Answer 14

last step in electrical signal pathway of heart; distribute the signal through the ventricular muscle

Question 15

intercalated discs

Answer 15

connects ventricular muscle; contain many gap junctions directly connecting cytoplasm of adjacent cells allowing for coordinated ventricular contraction

Question 16

vagus nerve

Answer 16

provides parasympathetic signals to slow hr

Question 17

systole

Answer 17

ventricular contraction and closure of the AV valves occurs and blood is pumped out of the ventricles

Question 18

diastole

Answer 18

heart is relaxed, seminlunar valves are closed and blood from the atria fills the ventricles

Question 19

Cardiac output

Answer 19

total blood volume pumped by a ventricle in a minute; CO = HR x SV (stroke volume, volume of blood pumped per beat); CO should = about 5 L per min

Question 20

endothelial cells

Answer 20

line all blood vessels; help to maintain vessel by releasing chemicals that aid in vasodilation and vasoconstriction; can allow WBCs to pass through the vessel wall and into the tissues during an inflammatory response; also release certain chemicals when damaged that are necessary for formation of blood clots to repair vessel

Question 21

only arteries that contain deoxygenated blood

Answer 21

pulmonary and umbilical

Question 22

only veins that carry oxygenated blood

Answer 22

pulmonary and umbilical

Question 23

superior vena cava (SVC)

Answer 23

returns blood from the portions of the body above the heart

Question 24

Inferior vena cava (IVC)

Answer 24

returns blood from portions of the body below the heart

Question 25

hepatic portal system

Answer 25

one of three portal systems in which blood passes through a series of two capillary beds (as opposed to just one) before returning to the heart; blood leaving capillary beds in walls of gut passes through hepatic portal vein before reaching capillary bed of the liver

Question 26

hypophyseal portal system

Answer 26

one of three portal systems in which blood passes through a series of two capillary beds (as opposed to just one) before returning to the heart; capillary beds in the hypothalamus then to capillary bed in anterior pituitary to allow for paracrine secretion of releasing hormones

Question 27

renal portal system

Answer 27

one of three portal systems in which blood passes through a series of two capillary beds (as opposed to just one) before returning to the heart; blood goes to glomerulus then travels through efferent arteriole before surrounding the nephron in a capillary network called vasa recta

Question 28

erythrocytes

Answer 28

RBCs contain roughly 250 million molecules of hemoglobin which each can bind 4 molecules of O2 which means RBCs carry about 1 billion molecules of O2 each; no mitochondria and rely entirely on glycolysis for ATP with lactic acid as main byproduct; can live for 120 days before cells in spleen and liver phagocytize them for their parts

Question 29

hematocrit

Answer 29

measure of how much of blood consists of RBCs, given as percentage norm for females is 36-46%, males is 41-53%,

Question 30

measure of Hemoglobin

Answer 30

quantity in blood given in grams per deciliter normal for females is 12-16. Males is 13.5-17.5

Question 31

leukocytes

Answer 31

WBCs about 4500-11,000 per microliter of blood.

Question 32

granulocytes

Answer 32

one of two classes of leukocytes, also called granular leukocytes: neutrophils, eosinophils, and basophils, contain cytoplasmic granules that are visible by microscopy; involved in inflammatory reactions, allergies, pus formation, destruction of bacteria and parasites

Question 33

agranulocytes

Answer 33

one of two classes of leukocytes; do not contain granules; consist of lymphocytes (important in specific immune response, the body's targeted fight against particular pathogens: B-cells responsible for antibody generation and T-cells that kill virally infected cells and activate other immune cells) and monocytes (phagocytize foreign matter such as bacteria, once in an organ renamed macrophages)

Question 34

microglia

Answer 34

macrophages of the CNS

Question 35

Langerhans cells

Answer 35

macrophages of the skin

Question 36

osteoclasts

Answer 36

macrophages of bone

Question 37

thrombocytes

Answer 37

platelets; fragments released from cells in bone marrow known as megakaryocytes; assist in blood clotting; 150,000-400,000 per microliter of blood

Question 38

hematopoiesis

Answer 38

production of blood cells and platelets; triggered by different hormones, growth factors and cytokines; most notable are erythropoietin secreted by kidney stimulates RBC development and thrombopoietin secreted by liver stimulating platelet development

Question 39

antigen

Answer 39

surface protein expressed by RBCs; any target to which the immune system can react; two major ones are ABO antigens and Rh factor

Question 40

ABO antigens

Answer 40

A (I^A) and B (I^B) are dominant. if one is present on one chromosome and the other on another blood is AB. O (i or O) is recessive but people this as blood type it do not express either variant and are homozygous recessive for O, however, A or B may have a recessive O that is not expressed (I^AI^A or I^Ai and so with B)

Question 41

Rh factor

Answer 41

refers mainly to presence (Rh +) or absence (Rh -) of D allele. Rh + is dominant and one is enough to make blood type positive. Rh+ can receive from - blood but - cannot receive from + which makes O universal regardless.

Question 42

erythroblastosis fetalis

Answer 42

condition in which mother's body begins making antibodies against fetal blood if mother's Rh factor is - and fetus's is +. Affects second childbirth only if both fetuses were opposite Rh factor of mom. anti-Rh IgG antibodies can cross the placenta but ABO IgM antibodies are unlikely to.

Question 43

Ohm's Law in circulation

Answer 43

Ohm's Law - V = IR is equivalent to deltaP = CO x TPR where P is pressure differential across the circulation, CO is cardiac output and TPR is total peripheral (vascular) resistance

Question 44

baroreceptors

Answer 44

specialized neurons (in walls of vasculature in circulation) that detect changes in the mechanical forces on the walls of the vessel; low bp, they cause vasoconstriction (sympathetic nervous response) increasing bp

Question 45

chemoreceptors

Answer 45

sense when osmolarity of blood is too high, which could indicate dehydration promoting release of antidiuretic hormone (ADH or vasopressin)

Question 46

atrial natriuretic peptide (ANP)

Answer 46

hormone secreted by the heart to help regulate bp; aids in loss of salt in the nephron, acting as a natural diuretic with the loss of fluid

Question 47

hemoglobin

Answer 47

protein with four cooperative subunits each with a prosthetic heme group which binds to an O2. Oxidation-reduction reaction with iron in heme groups; it is a positive feed-back/feedforward rxn. level of oxygen in blood is partial pressure of O2 or PsubaOsub2. Norm is bt 70-100 mmHg but often measured with pulse ox (percent of Hb carrying O2)

Question 48

cooperative binding

Answer 48

a form of allosteric regulation meaning that O2 binds more easily to rest of heme groups of hemoglobin after one O2 has bound and is removed progressively more easily as each O2 is removed. (feedforward). results in sigmoidal (S) of oxyhemoglobin dissociation curve

Question 49

carbonic anhydrase

Answer 49

when CO2 enters RBCs it encounters this enzyme which catalyzes the combination rxn bt CO2 and water to form carbonic acid (H2CO3) which is a weak acid that will dissociate into a proton and the bicarbonate ion (HCO3^-). Soluble in water and returned to lungs and exhaled in reverse of rxn that allowed it to get in in the first place: CO2 + H2O ->carbonic anhydrase

Question 50

Bohr effect

Answer 50

right shift of oxyhemoglobin dissociation curve caused by decreased blood pH (such as during exercise). causes increased PsubaCO2. Increased CO2 production causes a right shift in bicarbonate buffer equation producing more H+ and lowering pH. More H+ will bind to Hb and prevent oxygen binding which allows more O2 to be offloaded to tissues.

Question 51

causes of right shift of oxyhemoglobin dissociation curve

Answer 51

Bohr effect, temperature increase, and increased 2,3-bisphosphoglycerate (2,3-BPG) which is a side product of glycolysis

Question 52

causes of left shift of oxyhemoglobin dissociation curve

Answer 52

decreased PsubaCO2, decreased [H+], increased pH, decreased temp and decreased 2,3-BPG (2,3-bisphosphoglycerate); note that fetal hemoglobin (HbF) also has a higher affinity for oxygen and (HbA - adult) which is also a reason for a left shift

Question 53

respiratory alkalosis

Answer 53

blowing off excess CO2 causing blood to become more basic. kidneys compensate by increasing excretion of bicarb

Question 54

renal tubular acidosis type I

Answer 54

condition in which kidneys are unable to excrete acid effectively leading to metabolic acidosis causing buffer system to shift left. person may increase RR to compensate

Question 55

hydrostatic pressure

Answer 55

force per unit area that blood exerts against vessel walls generated by contraction of heart and elasticity of arteries (push out of vessels esp at arteriole end of capillary bed - starling force)

Question 56

osmotic pressure

Answer 56

called oncotic pressure because most of it is attributable to plasma proteins: "sucking" pressure generated by solutes as they attempted to draw water into the bloodstream (pull into vessels esp at venule end of capillary bed - starling force)

Question 57

edema

Answer 57

accumulation of excess fluid in interstitium

Question 58

thoracic duct

Answer 58

lymph (lymphatic fluid) is returned to the central circulatory system by way of this

Question 59

clots

Answer 59

composed of coagulation factors (proteins) and platelets; damaged tissue exposes collagen and tissue factor. platelets sense exposed collagen and coagulation factors sense tissue factor and initiate complex activation cascade

Question 60

end of complex activation cascade

Answer 60

(forming of a clot) - end is activation of prothrombin to form thrombin by thromboplastin. Thrombin then converts fibrinogen to fibrin which ultimately forms small net like fibers which capture RBCs and other platelets

Question 61

plasmin

Answer 61

generated from plasminogen - breaks down the clot formed for a scab