17-2: Pathway of circulation Flashcards Preview

A&P 2 - Unit 1 > 17-2: Pathway of circulation > Flashcards

Flashcards in 17-2: Pathway of circulation Deck (35)
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1
Q

The right atrium receives __ blood through __ pathways: _.

A

deoxygenated blood; three pathways; superior vena cava, inferior vena cava, coronary sinus

2
Q

superior vena cava

A

returns deoxy blood from organs above the heart and empties into R atrium

3
Q

inferior vena cava

A

returns deoxy blood from organs below the heart and empties into R atrium

4
Q

coronary sinus

A

returns deoxy blood from vessels supplying the myocardium and empties into R atrium

5
Q

The right ventricle receives _ blood from __; then pumps it through _.

A

deoxy; tricuspid valve; pulmonary SL valve into pulmonary trunk

6
Q

Deoxy blood entering the pulmonary trunk goes: __.

A

into right and left pulmonary arteries that carry the blood to the lungs, dropping off CO2 and picking up O2

7
Q

The left atrium receives _ blood from __.

A

oxy blood from the lungs through 4 pulmonary veins

8
Q

The left ventricle receives _ blood from _; then pumps it through _.

A

oxy; mitral/bicuspid valve; the aortic SL valve into aorta

9
Q

Oxy blood entering the aorta goes _.

A

into many major arteries supplying all body tissues with oxygen.

10
Q

Which ventricle has thicker walls?

A

left ventricle - pumping blood to a longer route through the whole body

11
Q

coronary circulation

A

heart tissues need their own blood vessels, because food and O2 can’t diffuse from blood inside the heart through the myocardium

12
Q

The coronary circulation originates as ___ branches off of the ___.

A

2 main branches; ascending aorta

13
Q

left coronary artery

A

runs to left side of heart and divides into two major branches: anterior interventricular artery and circumflex artery

14
Q

right coronary artery

A

runs to right side of heart and divdes into two major branches: marginal artery and the posterior interventricular artery

15
Q

anterior interventricular artery

A

branches from the left coronary artery

16
Q

posterior interventricular artery

A

branches from the right coronary artery

17
Q

marginal artery

A

branches from the right coronary artery

18
Q

circumflex artery

A

branches from the left coronary artery

19
Q

As blood delivers O2/nutrients and picks up CO2/waste from the cardiac cells, it is collected by ___ which empty into ___.

A

cardiac veins; coronary sinus

20
Q

coronary sinus

A

large vein on posterior surface of the heart where cardiac veins empty; it empties into the right atrium

21
Q

anastomosis

A

where several arteries supplying the same region merge; these fusing networks provide collateral routes for blood delivery to the myocardium

22
Q

conduction system

A

internal regulating system of the heart (even out of the body, the heart continues to beat)

23
Q

autorhythmicity

A

specialized cardiac cells spontaneously and rhythmically generate electrical impulses that stimulate the cardiac muscles to contract (unstable resting potential)

24
Q

syncytia

A

the cardiac muscle cells are so tightly connected at the intercalated discs, that when 1 fiber is stimulated, they all contract simultaneously as a unit

25
Q

The heart is divided into two syncytia: ___ and ___.

A

atrial syncytium and ventricular syncytium, separated by a wall of insulating connective tissue

26
Q

The conduction pathway consists of __ regions of ___ cells.

A

5; autorhythmic

27
Q

sinoatrial node

A

mass of self excitable cells in the wall of the right atrium, just below opening to SVC

28
Q

pacemaker cells

A

SA node - these cells set the pace for heart rate because they’re faster than other areas

29
Q

normal sinus rhythem

A

~75 bpm, but may be altered by nerve impulses from autonomic nervous system or chemicals

30
Q

The impulse generated by the SA node does what?

A

spreads rapidly over the atrial syncytium, causing the atria to contract simultaneously

31
Q

atrioventricular node

A

2nd mass of self excitable cells, at the base of the inter atrial septum; last part of atria to depolarize

32
Q

bundle of His

A

electrical bridge between the atria and ventricles, in the interventricular septem

33
Q

The bundle of His splits __, which terminate into __.

A

into right and left bundle branches; many Purkinje fibers

34
Q

What causes ventricular contraction?

A

stimulation of the ventricular syncytium by the Purkinje fibers

35
Q

What are the steps in the conduction pathway?

A
  1. SA node sets the pace;
  2. impulse travels through atrial syncythium, causing both atria to contract
  3. impulse travels to the AV node
  4. impulse travels down the bundle of His and interventricular septum, which branches into right and left bundle branches
  5. impulse travels from bundle branches to many Purkinje fibers, which stimulate the ventricular syncythium, causing both ventricles to contract