exam 2 class 12

Question 1

The pointed apex of heart angles down to left side of the body, while broader base lies just behind

Answer 1

breastbone, or sternum

Question 2

the heart lies on what side?

Answer 2

ventral side sandwiched
between two lungs,
with its apex resting
on diaphragm

Question 3

what does the thin layer of clear pericardial fluid do?

Answer 3

lubricates external surface of
heart as it beats within sac

Question 4

pulmonary veins are hidden
behind?

Answer 4

other major blood
vessels

Question 5

Inflammation of pericardium is?

Answer 5

pericarditis

Question 6

aorta and pulmonary trunk
(artery) direct blood from?

Answer 6

the heart to tissues and lungs

Question 7

the venae cavae
and pulmonary veins return?

Answer 7

blood to heart

Question 8

circuit that takes blood to the lungs and gills

Answer 8

pulmonary

Question 9

what are the two circulation circuits?

Answer 9

pulmonary
systemic

Question 9

circuit that takes blood to the body

Answer 9

systemic

Question 10

what partial pressures very in the circulatory system?

Answer 10

partial pressures of O2 and CO2

Question 11

Left and right sides of the heart are separated by?

Answer 11

septum

Question 12

what Two sets of heart valves ensure this one-way
flow?

Answer 12

atrioventricular valves
semilunar valves

Question 13

valves between
the atria and ventricles

Answer 13

Atrioventricular (AV)

Question 14

crescent-moon shape,
between the ventricles and their arteries

Answer 14

Semilunar (SL)
valves

Question 15

slightly thickened at the edge and connect on ventricular side to collagenous tendons

Answer 15

Aortic valve flaps

Question 16

tethered to ventricular muscle known as the
papillary muscle.

Answer 16

chordae tendineae

Question 17

the valve that separates the right atrium and right ventricle has three
flaps and is called ?

Answer 17

tricuspid valve

Question 18

The valve between the left atrium and left ventricle has only two flaps?

Answer 18

bicuspid valve
(also known as mitral valve)

Question 19

valve is between left ventricle and the aorta

Answer 19

SLV valve
or aortic semilunar valve

Question 20

lies between right ventricle and pulmonary trunk

Answer 20

Pulmonary valve

Question 21

has three
cuplike leaflets that snap closed when blood attempting to flow
back into ventricles fills them

Answer 21

semilunar valve

Question 22

what kind of blood in coronary circulation
is much lower in oxygen content than venous blood returning through
venae cavae?

Answer 22

venous blood

Question 23

Cardiac muscle consumes _______ of oxygen delivered to it by the blood, more than twice the amount extracted by other cells in the body

Answer 23

70–80%

Question 24

Bulk of heart is composed of ?

Answer 24

cardiac muscle cells, or myocardium

Question 25

Signal for myocardial contraction comes not from the nervous system but from specialized myocardial cells called?

Answer 25

autorhythmic cells also pace makers

Question 26

The signal for contraction is _________, originating within the heart muscle itself

Answer 26

myogenic

Question 27

how are cardiac muscles different form skeletal muscles?

Answer 27

1. cardiac muscle fiber are much smaller 2. cardiac ,muscle cells branch and join more cells 3. Gap junctions onnect cardiac muscle cells to one another 4.mitochondria occupy 1/3 of the cell volume

Question 28

intercalated disks have two components?

Answer 28

desmosomes and gap junctions

Question 29

- The filaments slide past one another - The sarcomere shortens with no change in lengths of the thin (actin) and thick (myosin) filaments themselves

Answer 29

contraction of sarcomere

Question 30

Thin filaments also contain proteins?

Answer 30

troponin and tropomyosin

Question 31

these work together to block myosin binding sites on actin

Answer 31

troponin and tropomyosin

Question 32

When calcium ions bind to troponin

Answer 32

the myosin binding site on actin is exposed, and contractions can begin

Question 33

The force generated by cardiac muscle is proportional to?

Answer 33

the number of cross bridges that are active

Question 34

The number of active cross bridges is determined by how much _______ is bound to troponin

Answer 34

Ca2+

Question 35

If cytosolic Ca2+ concentrations are low?

Answer 35

some cross bridges are not activated and contraction force is small

Question 36

Extracellular fluid?

Answer 36

more Na+ and Cl-

Question 37

interior of membrane?

Answer 37

lower Na+ & Cl- , higher K+

Question 38

Action potential depends on?

Answer 38

a voltage-gated channel

Question 39

The rapid depolarization phase of the action potential is the result of?

Answer 39

entry Na+, and the steep repolarization phase is due to K+ leaving the cell

Question 40

myocardial contractile cell has longer action potential due to?

Answer 40

Ca2+ entry

Question 41

what phase? resting membrane potential

Answer 41

Phase 4

Question 42

what phase? depolarization

Answer 42

Phase 0:

Question 43

what phase? initial repolarization

Answer 43

Phase 1:

Question 44

what phase? the plateau

Answer 44

phase 2