Lecture Overview Of Cardiovascular

Question 1

What does the CVS consist of?

Answer 1

Heart, blood, and blood vessels (arteries, veins, capillaries)

Question 2

What is the flow of blood?

Answer 2

Heart/ lungs, arteries, arterioles, capillaries, venules, veins and heart

Question 3

Primary function of the CVS?

Answer 3

Distribution of dissolved gases and other molecules for nutrition, growth and repair

Question 4

How is blood pumped to the heart?

Answer 4

Deoxygenated blood returns to the right heart, oxygenated in lungs and retuned to the left heart and the, pumped to the entire body

Question 5

Secondary functions of the CVS

Answer 5

Circulating hormones on NTs
Thermoregulation
Mediation of inflammatory and host defense responses against invading microorganisms

Question 6

What happens during BV dilation (vasodilation)?

Answer 6

Increased heat loss across the epidermis

Question 7

What happens during BV (vasoconstriction)

Answer 7

Heat conservation

Question 8

Epicardium

Answer 8

Is real layer of the serous pericardium

Question 9

Myocardium

Answer 9

Spiral bundles of cardiac muscle cells
Fibrous skeleton of the heart; interlacing layer of CT

Question 10

What are the functions of myocardium?

Answer 10

Anchors cardiac muscle fibers
Supports great vessels and valves
Limits spread of action potentials to specific paths

Question 11

Endocardium

Answer 11

Continuous with endothelial lining of blood vessels

Question 12

Cardiac skeleton

Answer 12

Annulus fibrosis
Forms and anchors valves
Partitions atria and ventricles

Question 13

What are the 2 pumps of the heart?

Answer 13

Left side: main pump
Right side: boost pump

Question 14

Systemic circulation

Answer 14

The left heart and all systemic arteries, capillaries and veins
The left ventricle will pump blood to all organs of the body except the lungs

Question 15

Pulmonary circulation

Answer 15

The right heart and pulmonary artery, capillaries and veins
Right ventricle pumps blood tot the lungs

Question 16

Central circulation

Answer 16

The pulmonary circulation and the heart

Question 17

How are the pulmonary and systemic circulation arranged?

Answer 17

In a series
Blood must pass through the pulmonary vessels between each passage through the systemic circuit

Question 18

When does the contraction of a cardiac muscle occur?

Answer 18

After an action potential

Question 19

How is the AP initiated by?

Answer 19

Spontaneously by pacemaker cells and propagated throughout the heart by way of the conducting system and gap junctions

Question 20

Where do most cardiac muscle cells remain stable?

Answer 20

Resting membrane potential

Question 21

Pacemaker cells

Answer 21

Cardiac cells that depolarize spontaneously toward threshold
They initiate heartbeats

Question 22

Wilhelm His Jr.

Answer 22

1863-1934
Discovered Bundle of His
First to recognize intracranial origin of heartbeat

Question 23

Sinus Node (SA node)

Answer 23

Small, flattened, ellipsoid strip of specialized cardiac muscle
No contractile muscle filaments

Question 24

Where are SA nodes located?

Answer 24

In the superior wall of the right atrium below and lateral to the opening of the superior vena cava

Question 25

Anteriorinteratrial band (Bachman’s bundle)

Answer 25

Internodal pathway
Passes through the walls of right atrium to left atrium

Question 26

What are the internodal pathways?

Answer 26

Anteriorinteratrial band, anterior, middle and posterior

Question 27

How do the other 3 internodal pathways run?

Answer 27

Curve through areas of the right atrial wall and terminate in the AV node

Question 28

AV node

Answer 28

Located in the dorsal wall of the right atrium behind the tricuspid valve

Question 29

Bundle of His (AV Bundle)

Answer 29

Passes downward in the ventricular septum toward the apex of the heart driving into left and right bundle branches

Question 30

AP conduction velocity of the SA and AV node?

Answer 30

0.02-0.01 m/s (slowest)
60-100
40-55 (AV node will take over if SA not working)

Question 31

AP conduction velocity of the pathways?

Answer 31

1 m/s

Question 32

AP conduction velocity of atrial and ventricular muscles

Answer 32

0.5 m/s

Question 33

AP conduction velocity and pacemaker rate of bundle of His and the lest and right bundle branches

Answer 33

2 m/s
25-40

Question 34

AP conduction velocity and pacemaker rate of purkinje fibers

Answer 34

4 m/s (fastest)
25-40

Question 35

Where does Norma, excitation originate?

Answer 35

In SA node then propagates through both atria

Question 36

Heart contraction

Answer 36

1. Atrial excitation begins at 0 when one SA node cell fires and AP
2. Within 0.1 seconds, the AP propagates across the atrias and contraction starts
3. AP propagates across the atria and depolarizes the cells in the AP nose at 0.04 sec
4. AP arrives at the ventricular apex 0.17 sec and takes 0.13 sec for AP to travel through the AV node and bundles
5. Ventricular depolarization is complete by 0.22 and both ventricles contract and atria have depolarized and are relaxing

Question 37

What is each cardiac muscle smell made of?

Answer 37

A few hundred myofibrils

Question 38

Myofibrils

Answer 38

Each one has a A band, I band, Z disk forming a sarcomere

Question 39

Sarcomere

Answer 39

Contractile unit of the muscle fiber
~0.1 mm (100um) long

Question 40

Intercalated disks

Answer 40

Cell membranes that separate individual cardiac muscle cells from each other

Question 41

What is formed for rapid diffusion of ions between fibers?

Answer 41

Cells membranes fuse and from permeable GJs at each intercalated disc

Question 42

Where do cardiac muscles contract?

Answer 42

In the syncytium since the action rapidly spreads across the organ

Question 43

What are the 2 syncytia?

Answer 43

Atrial syncytium (walls of 2 atria)
Ventricular syncytium (walls of 2 ventricles)