Chapter 20 Lecture 3

Question 1

What are required for directional circulation?

Answer 1

Pump
Valves  
Muscle location/structure
Timing of contractions
Tubes in a circuit

Question 2

Valves:

Answer 2

one-way entrance and exit

Question 3

A-V valves open and:

Answer 3

allow blood to flow from atria into ventricles when ventricular pressure is lower than atrial pressure

Question 4

A-V valves close and:

Answer 4

prevent backflow of blood into atria

Question 5

SL valves open

Answer 5

Semilunar - with ventricular contraction

allow blood to flow into pulmonary trunk and aorta

Question 6

SL valves close

Answer 6

with ventricular relaxation

prevents blood from returning to ventricles, blood fills valve cusps, tightly closing the SL valves

Question 7

Pre-load

Answer 7

1. Ventricles relax, drawing blood into atria

2. Atria then contract, sending blood into ventricles

Question 8

After Load:

Answer 8

3. Ventricles contract, blood enters ascending aorta and pulmonary arteries

Question 9

Stenosis -

Answer 9

valve narrowing (restricts blood flow)

Question 10

Insufficiency –

Answer 10

valve does not close completely (“murmur”; congenital, scar tissue or autoimmune damage from disease)

Question 11

Prolapse –

Answer 11

valve cusp escapes backwards into previous chamber (blood backflow)

Question 12

Septal defect –

Answer 12

opening between chambers, usually between ventricles (allows mixing of oxygenated and deoxygenated blood)

Question 13

3 Circuit:

Answer 13

Pulmonary, Systematic, Coronary

Question 14

Pulmonary Circuit:

Answer 14

right ventricle –> deoxygenated blood to/from lungs –> 1. left atrium

2. right side of heart pumps deoxygenated blood to lungs
3. right ventricle pumps blood to pulmonary trunk
4. pulmonary trunk branches into pulmonary arteries
5. pulmonary arteries carry blood to lungs for exchange of gases
6. oxygenated blood returns to heart in pulmonary veins

Question 15

Systematic Circuit:

Answer 15

left ventricle –> oxygenated to/from body –> right atrium

1. pumps oxygenated blood into aorta
2. aorta branches into many arteries that travel to organs
3. arteries branch into many arterioles in tissue
4. arterioles branch into thin-walled capillaries for exchange of gases and nutrients
5. begins its return in venules
6. venules merge into veins and return to right atrium

Question 16

Coronary Circuit:

Answer 16

left ventricle –> ascending aorta –> myocardium –> coronary sinus –> right atrium
1.Thick myocardium needs separate, dedicated cardiac circulation
2. Two arteries branch immediately off ascending aorta:
left coronary artery:
right coronary artery:
3. Largely parallel veins

Question 17

Blood flow

Answer 17

blue = deoxygenated
red = oxygenated

Question 18

Coronary Circulation is:

Answer 18

blood supply to the heart

• Heart as a very active muscle needs lots of O2
• When the heart relaxes high pressure of blood in aorta pushes blood into coronary vessels
• Many anastomoses (branches come back together in short distances)

Question 19

Coronary arteries:

Answer 19

Branches off aorta above aortic semilunar valve

Question 20

Left coronary artery:

Answer 20

circumflex branch
-supplies left atrium and left ventricle
anterior interventricular art.
-supplies both ventricles

Question 21

Right coronary artery:

Answer 21

marginal branch
-supplies right ventricle
posterior interventricular art.
-supplies both ventricles

Question 22

Coronary Veins:

Answer 22

Collects wastes from cardiac muscle
Drains into a large sinus on posterior surface of heart called the coronary sinus
Coronary sinus empties into right atrium

Question 23

Principal tributaries of coronary sinus

Answer 23

Great cardiac vein
Middle cardiac vein
Small cardiac vein
Anterior cardiac veins

Question 24

Cardiac Muscle Histology

Answer 24

Branching, intercalated discs with gap junctions, involuntary, striated, single central nucleus per cell

Question 25

Structured much like skeletal:

Answer 25

striated with overlapping actin and myosin filaments

Question 26

Interconnected by many gap junctions =

Answer 26

pass deplorization from cell-to-cell.

Question 27

Able to produce&raquo_space; ATP:

Answer 27

more mitochondria