Biology 7: The Cardiovascular System

Question 1

which part of the heart is more muscular: ventricles or atria?

Answer 1

ventricles are more muscular than the atria, allowing for more powerful contractions necessary to push blood through the rest of the cardiovascular system

the left heart is more muscular than the right heart so that it can pump blood to the body

Question 2

the two atrioventricular valves are…

Answer 2

tricuspid valve between the right atrium and right ventricle

mitral/bicuspid valve between the left atrium and left ventricle

Question 3

the two semilunar values are…

Answer 3

pulmonary valve

aortic valve

Question 4

pathway of electrical conduction of the heart:

Answer 4

sinoatrial (SA) node -> atrioventricular (AV) node -> bundle of His -> purkinje fibers

Question 5

impulse initiation occurs at this point of the heart

Answer 5

SA node in the wall of the right atrium

causes the two atria to contract simultaneously

has an intrinsic rhythm of 60-100 signals/minute - setting normal HR

Question 6

atrial systole

Answer 6

contraction of the atria

increases atrial pressure, forces more blood into the ventricles (atrial kick)

[most ventricular filling is passive]

Question 7

AV node

Answer 7

node at the junction of the atria and ventricles

delays electrical signal to allow the ventricles to fill completely before they contract

Question 8

what bundle of nerves from the AV node are embedded in the interventricular septum?

Answer 8

bundle of His

Question 9

what fibers distribute electrical signal through ventricular muscle?

Answer 9

purkinje fibers

Question 10

how are cardiac muscle cells connected?

Answer 10

by intercalated discs, which contain gap junction directly connecting the cytoplasm of adjacent cells

allow for coordinated ventricular contraction

Question 11

vagus nerve

Answer 11

provides parasympathetic signals to cardiac muscle, slowing HR

Question 12

systole

Answer 12

ventricular contraction

AV valves closed, semilunar valves open

blood pumped out ventricles

higher pressure

Question 13

diastole

Answer 13

heart is relaxed, blood from atria fills ventricles

AV valves open, semilunar valves closed

lower pressure

Question 14

cardiac output (CO) =

Answer 14

heart rate (HR) x stroke volume (SV)

Question 15

portal system

Answer 15

a system in which blood passes through two capillary beds in series before returning to the heart

Question 16

hepatic portal system

Answer 16

allows blood to travel from the gut capillary beds to the liver capillary bed

Question 17

hypophyseal portal system

Answer 17

allows blood to travel from the hypothalamus to the anterior pituitary

Question 18

renal portal system

Answer 18

allows blood to travel from the glomerulus to the vasa recta through an efferent arteriole

Question 19

what is blood composed of?

Answer 19

plasma - liquid portion

erythrocytes - RBC

leukocytes - WBC

thrombocytes - platelets

Question 20

hematocrit

Answer 20

measurement of how much of the blood sample consists of RBC

Question 21

what are the granulocytes?

Answer 21

neutrophils, eosinophils, basophils

contain granules of compounds that are toxic to invading microbes and so are involved in inflammatory reactions, allergies, pus, destruction of bacteria/parasites

Question 22

what are the agranulocytes?

Answer 22

lymphocytes, monocytes

Question 23

lymphocytes

Answer 23

WBC important in specific immune response, binding to antigens either as first responders or as memory cells

B-cells, T-cells, NK cells

Question 24

monocytes

Answer 24

WBC that phagocytize foreign matter

called macrophages once they enter an organ

Question 25

eosinophils

Answer 25

WBC that combat parasites, inflammation, allergic reactions

Question 26

neutrophil

Answer 26

phagocytic granular WBC that engulf and destroy bacteria

Question 27

basophils

Answer 27

WBC that store histamine and heparin (removal of fat particles from the blood)

Question 28

dP (pressure differential across circulation) =

Answer 28

cardiac output (CO) x total peripheral resistance (TPR)

Question 29

resistance depends on…

Answer 29

greater resistivity

longer length

lower cross-sectional area

Question 30

what specialized neurons detect changes in the mechanical forces on the walls of the blood vessel?

Answer 30

baroreceptors

Question 31

antidiuretic hormone / ADH / vasopressin

Answer 31

peptide hormone released when chemoreceptors sense the osmolarity of the blood is too high

produced in the hypothalamus, stored in posterior pituitary

increases reabsorption of water, increasing blood volume and pressure

Question 32

aldosterone

Answer 32

release stimulated by low blood flow to juxtaglomerular cells in kidney

uses renin-angiotensin-aldosterone system

increases the reabsorption of sodium (and therefore water), increasing blood volume and pressure

Question 33

atrial natriuretic peptide (ANP)

Answer 33

hormone secreted by specialized atrial cells

aids in the loss of salt in the nephron, acts as weak diuretic

decreases blood volume and pressure a little bit

Question 34

bohr effect

Answer 34

hemoglobin has a decreased affinity to oxygen due to a decrease in pH

higher rates of cell metabolism = increase CO2 production, increase lactic acid production = decreased pH

more O2 unloaded at tissues

Question 35

hydrostatic pressure

Answer 35

force that the blood exerts against the vessel walls

generated by contraction of heart and elasticity of arteries

pushes fluid out of the capillary walls

higher at the arteria lend than the venous end

Question 36

osmotic pressure

Answer 36

sucking/pulling pressure generated by solutes as they try to draw water into bloodstream

remains relatively constant across the length of a capillary

Question 37

plasmin

Answer 37

protein which breaks down blood clots

Question 38

thrombin

Answer 38

protein that converts fibrinogen to fibrin