Cardio 1 histo (physio)

Question 1

There are 2 systems that are responsible for moving fluid around your body. They are separate but are connected components: The blood vascular component called the cardiovascular system, and the lymphatic vascular system which collects and returns excess ECF (lymph) to the blood vascular system. The cardiovascular system includes………….. circulation and …………… circulation.

Answer 1

pulmonary circulation

systemic circulation

Question 2

The cardiovascular system includes the heart, Arteries (a series of………. vessels from the heart which carry blood to other organs), Capillaries (the smallest vessels, site of O2,CO2, nutrient and waste product exchange between blood and tissues), and veins.

Answer 2

efferent

Question 3

What are the three layers of the heart? (from innermost to outermost)

Answer 3

Endocardium
Myocardium
Pericardium

Question 4

…………..is also known as the visceral layer of pericardium.

Answer 4

EPICARDIUM

Question 5

The outermost layer of epicardium is covered by simple squamous epithelium called……………
Deep to this is a fibrous elastic connective tissue.

Answer 5

mesothelium

Question 6

Epicardium (the visceral layer of pericardium) contains the blood vessels and nerves that……… The epicardium is reflected on the great vessels entering and leaving the heart.
There is a potential space, the pericardial cavity which contains a serous (pericardial) fluid around the heart.

Answer 6

supply the heart

Question 7

MYOCARDIUM is the most well developed layer, which consists of bundles of…………… that are attached to the thick collagenous connective tissue skeleton of the heart .

Answer 7

cardiac muscle

Question 8

The myocardium consists of 3 cell types :

1. ………….. cardiocytes, which contract to pump blood through the circulation.
2. …………. cardiocytes, producing atrial natriuretic factor.
3. ………….. cardiocytes, which are specialized to control rhythmic contraction of the heart.

Answer 8

Contractile
Myoendocrine
Nodal

Question 9

Where are nodal cardiocytes located?

Answer 9

the sinoatrial node and the atrioventricular node.

Question 10

Endocardium is the inner most layer and is composed of………………. endothelium as well as a…………… tissue .

Answer 10

simple squamous

sub endothelial fibroelastic connective

Question 11

The endocardium participates in the formation of……………

Answer 11

heart valves

Question 12

The…………………….. layer lies deep to the endocardial layer. It is comprised of collagenous and elastic fibers .
Small blood vessels and…………. fibers are found here .
This layer attaches to the endomysium of the cardiac muscle fibers.

Answer 12

Sub endocardial layer

Purkinje

Question 13

Cardiac muscle cells (……………) are branched cylinders that are 85-100 µm long, 15 µm in diameter, and have what kind of nucleus?

Answer 13

cardiocytes

single centrally placed nucleus

Question 14

What are the 4 differences to note about myocardium compared to skeletal muscle?

Answer 14

1. The T TUBULES are found at the level of the Z DISC & are substantially LARGER than those of skeletal muscle found at the A-I junction.
2. The sarcoplasmic reticulum is NOT AS EXTENSIVE as that of skeletal muscle.
3. DIADS, (rather than triads seen in skeletal muscle) are typical in cardiocytes. A diad consists of a T tubule interacting with just one sarcoplasmic reticulum (instead of 2 as in skeletal muscle)
4. Mitochondria are MORE ABUNDANT in the cardiac muscle and contain numerous cristae.

Question 15

The cardiocytes are joined end to end by specialized junctional complexes called…………….

Answer 15

intercalated discs

Question 16

Intercalated discs appear at varying intervals and have a STEP LIKE arrangement, with…………. components that run perpendicular to the long axis of the cell and…………….. components running parallel to the cardiocytes .

Answer 16

Transverse

longitudinal

Question 17

The intercalated discs possess what 3 important specializations?
* These specializations allow the passage of ions to pass freely there by resulting in a wave of contraction that spreads through out the heart wall.

Answer 17

Desmosomes
Fascia adherens
Gap junctions

Question 18

When stretched, cardiac muscle cells (myoendocrine cardiocytes) in the ATRIA secrete a potent polypeptide hormone called…………….. that stimulates diuresis and natriuresis .
Atrial cardiocytes contain membrane bound storage granules and a more highly developed Golgi apparatus and rER than their ventricular counterparts.

Answer 18

atrial natriuretic factor (ANF)

Question 19

What does atrial natriuretic factor (ANF) do?

Answer 19

• prevents sodium and water reabsorption (therefore preventing hypervolemia and hypertension that can result in cardiac failure)
• relaxes the cardiovascular muscle by antagonizing the action of vasopressin and angiotensin II .

Question 20

………………. is the principal mediator of ANF release as a prohormone . Once outside the atrial cell , the ANF prohormone undergoes a rapid enzymatic cleavage to produce the principal form of circulating ANF.

Answer 20

Increasing atrial pressure

Question 21

When it comes to the fibrous skeleton of the heart,
………………………………. connective tissue with thick collagen fibers is present in these locations:
- around the bases of aorta, pulmonary artery and atrioventricular orifices.
- near the aortic valve cusp.
- at the upper portion of atrioventricular septum.

Answer 21

dense irregular collagenous

Question 22

What are the functions of the fibrous skeleton of the heart?

Answer 22

• Structural support for the heart.
• Point of attachment for cardiac muscle.
• Structural discontinuity between the atrial and ventricular muscle, thus ensuring the contraction of atria and ventricles will not occur simultaneously.

Question 23

CARDIAC VALVES have a core of…………. connective tissue with…………… covering both sides. The valves attach to the fibrous skeleton.

Answer 23

fibrous

endothelium

Question 24

What are the components of the conduction system of the heart? (list in order)

Answer 24

Sinoatrial node (SA node)
Atrioventricular node (AV node)
AV bundle of His 
R & L bundle branches 
Purkinje fibers

Question 25

Each wave of heart contraction is initiated in the myocardium. Contraction must begin in the atria and the atrial contraction must finish at what point?

Answer 25

Just before the beginning of ventricular contraction.

Question 26

The cells in the AV node and internodal tract conduct impulses relatively……….

Answer 26

slowly

Question 27

Purkinje fibers are a specialized population of cells found in the distal portions of the…….. nodes and continuing into the left and right bundle branches .

Answer 27

AV

Question 28

What are the specialized functions of purkinje fibers?

Answer 28

Specialized for rapid impulse conduction. (Therefore they contain abundant glycogen)

Question 29

Purkinje cells are found in what specific tissue layer?

Answer 29

The sub endothelial connective tissue of the ventricular walls.

Question 30

What neural components innervate the heart?

Answer 30

Both parasympathetic and sympathetic neural components.

Question 31

Ganglionic nerve cells and nerve fibers are present in the regions close to SA and AV nodes, where they affect…………………

Answer 31

heart rate and rhythm

Question 32

Stimulation of the parasympathetic division (via the……………… nerve) slows the heart beat.

Answer 32

Vagus

Question 33

Stimulation of the sympathetic nerve…………. activity of the pacemaker.

Answer 33

accelerates

Question 34

Between the fibers of the myocardium are afferent free nerve endings that register pain, such as discomfort called………………., that occurs when partially occluded coronary arteries cause local oxygen deprivation

Answer 34

angina pectoris

Question 35

…………….. is a functional syncytium of cardiac myocytes.

Answer 35

Myocardium