Chapter 42: Circulation and Gas Exchange

Question 1

circulatory systems

Answer 1

connect isolated cells to external environment to facilitate exchange

Question 2

gastrovascular cavity

Answer 2

lack specialized circulatory system; have a high surface area to volume ratio. ie, cnidarians, flatworms

Question 3

circulatory fluid

Answer 3

carries resources/wastes

Question 4

interconnecting tubes

Answer 4

component of circulatory system thru which fluid travels

Question 5

heart

Answer 5

muscular pump

Question 6

open circulatory systems

Answer 6

circulatory fluid (hemolymph) in direct contact with organs; same as interstitial fluid; ie, arthropods, most mollusks

Question 7

advantages of open circulatory system

Answer 7

lower pressures, can use fluid as hydrostatic skeleton

Question 8

closed circulatory system

Answer 8

circulatory fluid (blood) in vessels, separate from interstitial fluid; ie, annelids, vertebrates

Question 9

advantages of closed circulatory systems

Answer 9

faster delivery of O2, easier to regulate

Question 10

cardiovascular system

Answer 10

vertebrate circulatory system

Question 11

atrium

Answer 11

chamber of the heart that receives blood

Question 12

ventricle

Answer 12

chamber of the heart that pumps blood away

Question 13

arteries

Answer 13

carry blood away from heart; branch into arterioles

Question 14

capillaries

Answer 14

where exchange takes place

Question 15

capillary bed

Answer 15

network of capillaries

Question 16

veins

Answer 16

carry blood back to heart

Question 17

single circulation

Answer 17

blood pumped thru a single circuit; in fishes with 2-chambered hearts. runs at lower pressure, so lower velocity

Question 18

double circulation

Answer 18

blood pumped thru two separate circuits; in tetrapods with 3- or 4-chambered hearts. maintains higher pressure/velocity of blood

Question 19

pulmonary circuit

Answer 19

circuit that pumps blood to lungs

Question 20

systemic circuit

Answer 20

circuit that pumps blood to body

Question 21

steps in the flow of blood thru both circuits

Answer 21

right ventricle pumps blood to lungs via the pulmonary arteries, blood flows thru capillary beds of the left and right lungs (gas exchange) and then returns to left atrium via pulmonary veins. left ventricle pumps blood out to body via the aorta (including coronary arteries to the heart). one branch leads to capillary beds in head and arms, another branch leads to capillary beds in the head and arms, another branch leads to capillary beds in the abdomen and legs. deoxygenated blood drains head and arms via superior vena cava, drains the abdomen and legs via the inferior vena cava, and both empty to the right atrium.

Question 22

cardiac cycle

Answer 22

complete sequence of pumping (systole) and filling (diastole)

Question 23

heart rate

Answer 23

avg. 72 beats per minute

Question 24

stroke volume

Answer 24

avg. 70 mL per ventricle

Question 25

cardiac output

Answer 25

avg. 5 L/minute (per ventricle)

Question 26

valves

Answer 26

one-way flaps, bigger than the opening they cover

Question 27

valve types

Answer 27

atrioventricular valve (AV): between chambers semilunar valve: between ventricles and arteries

Question 28

heart murmur

Answer 28

defective valve leads to back-flow

Question 29

pacemaker

Answer 29

autorhythmic cells of heart; contraction based upon own electrical impulses

Question 30

sinoatrial node

Answer 30

beginning of electrical impulses, cause atria to contract

Question 31

atrioventricular node

Answer 31

relay electrical impulses after 0.1 s delay, ventricles contract

Question 32

vessels structure

Answer 32

open lumen lined by endothelium (single epithelial layer)

Question 33

arterial structure

Answer 33

layer of smooth muscle, then layer of elastic connective tissue. thicker than veins (higher pressure), muscle can contract to control flow

Question 34

vein structure

Answer 34

layer of smooth muscle and connective tissue; thinner with valves to prevent back-flow

Question 35

blood pressure change in capillary beds

Answer 35

total cross-section area increases; velocity of blood decreases thru the capillaries

Question 36

precapillary sphincters

Answer 36

close off paths through capillary beds; controlled by nervous system and hormones

Question 37

exchange of water by pressure

Answer 37

blood pressure forces water out at arterial end, osmotic pressure draws water back at venous end

Question 38

lymph

Answer 38

network of small vessels that drains excess interstitial fluid

Question 39

blood

Answer 39

circulatory fluid in closed circulatory system made up of connective tissue cells and plasma

Question 40

plasma

Answer 40

liquid matrix of blood; 90% water dissolved with salts, proteins, gases, wastes, hormones, etc.

Question 41

erythrocytes

Answer 41

red blood cells, function mainly in O2 transport. lack nuclei, full of hemoglobin

Question 42

hemoglobin

Answer 42

oxygen transport protein

Question 43

leukocytes

Answer 43

white blood cells; perform various immune function

Question 44

platelets

Answer 44

cell fragments involved in blood clotting

Question 45

clotting

Answer 45

damage plugged by platelets and reinforced by fibrin protein

Question 46

stem cells

Answer 46

located in bone marrow, produce new blood cells

Question 47

partial pressure

Answer 47

fraction of the total pressure exerted by air

Question 48

diffusion of oxygen

Answer 48

must be exchanged thru water; cell membranes need moist surfaces

Question 49

gills

Answer 49

respiratory surface of fish

Question 50

countercurrent exchange (fish)

Answer 50

moves surface of gills through medium, capillaries flow in the opposite direction; removes 80% of dissolved O2. won't work on land

Question 51

tracheal system

Answer 51

adaptation for breathing air in insects, series of air tubes that branches throughout body. does not involve circulatory system

Question 52

lungs

Answer 52

adaptation for breathing air in vertebrates

Question 53

nostrils function

Answer 53

filter, warm and moisten air as its taken in

Question 54

larynx

Answer 54

receives air via pharynx and opens to trachea

Question 55

bronchi

Answer 55

trachea branches into two bronchi, which continue to branch into bronchioles

Question 56

bronchioles

Answer 56

surface covered by cilia and mucus to remove waste; end in alveoli

Question 57

amphibians ventilation

Answer 57

positive pressure breathing; push air in by shrinking oral cavity

Question 58

mammals ventilation

Answer 58

negative pressure breathing; pull air in

Question 59

diaphragm

Answer 59

skeletal muscle that expands thoracic cavity to pull air in

Question 60

breathing control centers

Answer 60

control breathing in brain by negative feedback; coordinated with circulatory system

Question 61

bird ventilation

Answer 61

one way flow of air by use of posterior and anterior air sacs; more efficient and complex

Question 62

partial pressures of O2 and CO2

Answer 62

net diffusion of O2 to the blood, CO2 diffuses from blood to air, O2 is transported throughout the body, CO2 is loaded from cells to the blood

Question 63

necessity of hemoglobin

Answer 63

transports higher quantities of O2 than water to reduce necessary cardiac output