Chapter 42: Circulation and Gas Exchange (897-922)

Question 1

What surfaces does fluid cover in gastrovascular cavities?

Answer 1

both inner and outer tissue layers: facilitates exchange of gases and cellular wastes

Question 2

What kinds of organisms can survive without a circulatory system?

Answer 2

planarians, mother other flatworms

Question 3

open circulatory system

Answer 3

circulatory fluid bathes the organs directly: arthropods and most molluscs

Question 4

What is the circulatory fluid of open circulatory systems?

Answer 4

hemolymph: also interstitial fluid that bathes the body cells

Question 5

closed circulatory system

Answer 5

blood si confined to vessels that branch into smaller ones that infiltrate the organs: chemical exchange occurs between blood and interstitial fluid and body cells

Question 6

What organisms have closed circulatory systems?

Answer 6

annelids, cephalopods, all vertebrates

Question 7

benefits of closed circulatory systems

Answer 7

relatively high blood pressures (effective delviery), larger and more active animals, well suited to regulation of food distribution to different organs

Question 8

benefits of open circulatory systems

Answer 8

lower hydrostatic pressures, less energy-costly, additional functions such as movement

Question 9

cardiovascular system

Answer 9

closed circulatory system of humans and other vertebrates: blood circulates to and from heart through vessel network

Question 10

arteries

Answer 10

carry blood away from heart to organs

Question 11

arterioles

Answer 11

small vessels that convey blood to capillaries

Question 12

capillaries

Answer 12

microscopic vessels with thin, porous walls: make up capillary beds in every tissue; good for diffusion

Question 13

venules

Answer 13

capillaries converge into venules

Question 14

veins

Answer 14

venules converge into veins, which bring blood back to the heart

Question 15

atria

Answer 15

chambers that receive blood

Question 16

ventricles

Answer 16

chemabers responsible for pumping blood back out of the heart

Question 17

single circulation

Answer 17

blood passes through the heart once per circuit: bony fishes, rays, sharks: two-chambered hearts

Question 18

how does single circulation work?

Answer 18

blood enters atrium, transferred to ventricle, pumped to gills to receive oxygen, back to capillaries, back to heart

Question 19

double circulation

Answer 19

two circuits: amphibians, reptiles, mammals

Question 20

pulmonary circuit

Answer 20

right side of heart: oxygen-poor blood delivered to capillary beds of gas exchange tissues for oxygen

Question 21

systemic circuit

Answer 21

left side: oxygen rich blood propelled to rest of body, then returns to heart for recirculation through the systemic circuit

Question 22

blood flow in mammalian circulation

Answer 22

RV - pulmonary arteries - capillary beds of lungs - oxygenated - pulmonary veins - LA - bicuspid - LV - aorta - arteries and coronary artery - capillary beds of body - deoxygenated - veins - superior and inferior vena cava - RA - triscuspid - RV - repeat

Question 23

which heart chambers have thicker walls and contract more forcefully?

Answer 23

ventricles

Question 24

systole

Answer 24

contraction phase of the cardiac cycle

Question 25

diastole

Answer 25

relaxation phase of the cardiac cycle

Question 26

what two factors control cardiac output?

Answer 26

heart rate and stroke volume

Question 27

atrioventricular valve

Answer 27

lies between the atrium and ventrium on each side: anchored by strong fibers that prevent them from turning inside out

Question 28

semilunar valves

Answer 28

two exits of the heart: where aorta leaves LV, where pulmonary artery leaves RV