Chapter 20 Lecture 3 Flashcards Preview

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Flashcards in Chapter 20 Lecture 3 Deck (27):
1

What are required for directional circulation?

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

2

Valves:

one-way entrance and exit

3

A-V valves open and:

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

4

A-V valves close and:

prevent backflow of blood into atria

5

SL valves open

Semilunar - with ventricular contraction
allow blood to flow into pulmonary trunk and aorta

6

SL valves close

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

7

Pre-load

1. Ventricles relax, drawing blood into atria
2. Atria then contract, sending blood into ventricles

8

After Load:

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

9

Stenosis -

valve narrowing (restricts blood flow)

10

Insufficiency –

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

11

Prolapse –

valve cusp escapes backwards into previous chamber (blood backflow)

12

Septal defect –

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

13

3 Circuit:

Pulmonary, Systematic, Coronary

14

Pulmonary Circuit:

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

15

Systematic Circuit:

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

16

Coronary Circuit:

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

17

Blood flow

blue = deoxygenated
red = oxygenated

18

Coronary Circulation is:

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)

19

Coronary arteries:

Branches off aorta above aortic semilunar valve

20

Left coronary artery:

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

21

Right coronary artery:

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

22

Coronary Veins:

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

23

Principal tributaries of coronary sinus

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

24

Cardiac Muscle Histology

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

25

Structured much like skeletal:

striated with overlapping actin and myosin filaments

26

Interconnected by many gap junctions =

pass deplorization from cell-to-cell.

27

Able to produce >> ATP:

more mitochondria