Circulatory System (*)

Question 1

The system consisting of the heart, arteries, veins, and microvascular beds is organized as the _______ -________ and _______ _______

Answer 1

pulmonary circulation and the systemic circulation

Question 2

describe blood flow with pulmonary circulation

Answer 2

In the pulmonary circulation the right side of the heart pumps blood through pulmonary vessels, through the lungs for oxygenation, and back to the left side of the heart.

Question 3

describe blood flow with systemic circulation

Answer 3

The larger systemic circulation pumps blood from the left side of the heart through vessels supplying either the head and arms or the lower body, and back to the right side of the heart

Question 4

When the body is at rest, approximately _____% of the blood moves through the systemic circulation, about _____ % through the pulmonary circulation, and _____% through the heart.

Answer 4

70, 18, 12

Question 5

the human heart has ____ atria and _____ ventricles

Answer 5

2, 2

Question 6

describe the cardiac conducting system

Answer 6

initiates the electrical impulse for contraction (heartbeat) and spreads it through the ventricular myocardium

Question 7

what is the function of the sinoatrial node

Answer 7

pacemaker

Question 8

describe the atrioventricular (AV) node

Answer 8

consist of myocardial tissue that is difficult to distinguish histologically from surrounding cardiac muscle. The AV node is continuous with specialized bundles of cardiac muscle fibers, the AV bundles (of His) that run along the interventricular septum to the apex of the heart, where they branch further as conducting (Purkinje) fibers that extend into myocardium of the ventricles.

Question 9

what does the endocardium consist of?

Answer 9

endothelium, a thin layer of connective tissue with smooth muscle cells, and a layer of variable thickness lacking smooth muscle called the subendocardial layer.

Question 10

what are purkinje fibres?

Answer 10

These fibers are cardiac muscle cells joined by intercalated disks but specialized for impulse conduction rather than contraction. With glycogen filling much of the cytoplasm and displacing myofibrils to the periphery, Purkinje fibers typically are more pale staining than contractile cardiac muscle fibers

Question 11

the _________, is the site of the coronary vessels and contains considerable adipose tissue

Answer 11

epicardium

Question 12

The ________cells secrete a lubricant fluid that prevents friction as the beating heart contacts the parietal pericardium on the other side of the pericardial cavity

Answer 12

mesothelial

Question 13

descirbe compliance

Answer 13

how much a compartment will expand if the pressure in that compartment is change. A balloon has a high compliance because a small pressure increase inside the balloon will greatly expand the balloon. A rigid tube has a low compliance because a small pressure increase inside the rigid tube will not result in a significant increase in the volume of the rigid tube.

Question 14

describe elasticity

Answer 14

tendency to return to initial structure after being distended

Question 15

Walls of both arteries and veins have three tunics called ?

Answer 15

1. intima
2. media
3. adventitia

Question 16

An_______ has a thicker media and relatively narrow lumen. A _______ has a larger lumen and its adventitia is the thickest layer.

Answer 16

artery, vein

Question 17

The intima of veins is often folded to form ______

Answer 17

valves

Question 18

Capillaries have only an endothelium, with no ________ layer or other tunics.

Answer 18

subendothelial

Question 19

The _______ arteries contain considerable elastic material and expand with blood when the heart contracts.

Answer 19

largest

Question 20

not all interstitial fluid formed at capillary beds is drained into venules; the excess is called ___ and collects in thin-walled, irregularly shaped lymphatic vessels

Answer 20

lymph

Question 21

Arterioles are microvessels with an ___________

Answer 21

intima

Question 22

In skin blood flow can be varied according to external conditions by _________ -____________, or anastomoses, commonly coiled, which directly connect the arterial and venous systems and temporarily bypass capillaries.

Answer 22

arteriovenous (AV) shunts

Question 23

describe the venus portal system

Answer 23

one capillary bed drains into a vein that then branches again into another capillary bed. This arrangement allows molecules entering the blood in the first set of capillaries to be delivered quickly and at high concentrations to surrounding tissues at the second capillary bed, which is important in the anterior pituitary gland and liver.

Question 24

describe the arterial portal system

Answer 24

afferent arteriole → capillaries → efferent arteriole which occur in the kidney.

Question 25

Capillaries are normally associated with perivascular contractile cells called

Answer 25

pericytes

Question 26

what are the 3 types of vessels between arterioles and venules?

Answer 26

1. continuosu capillaries
2. fenestrated capillaries
3. sinusoids

Question 27

descirbe continuous capillaries

Answer 27

the most common type, have tight, occluding junctions sealing the intercellular clefts between all the endothelial cells to produce minimal fluid leakage. All molecules exchanged across the endothelium must cross the cells by diffusion or transcytosis.

Question 28

describe sinusoids

Answer 28

discontinuous capillaries, usually have a wider diameter than the other types and have discontinuities between the endothelial cells, large fenestrations through the cells, and a partial, discontinuous basement membrane. Sinusoids are found in organs where exchange of macromolecules and cells occurs readily between tissue and blood, such as in bone marrow, liver, and spleen.

Question 29

fenestrated capillaries

Answer 29

capillaries also have tight junctions, but perforations (fenestrations) through the endothelial cells allow greater exchange across the endothelium. The basement membrane is continuous in both these capillary types. Fenestrated capillaries are found in organs where molecular exchange with the blood is important, such as endocrine organs, intestinal walls, and choroid plexus.

Question 30

____________capillaries exert the tightest control over what molecules leave and enter the capillary lumen

Answer 30

Continuous

Question 31

what is the function of fenestrated capillaries?

Answer 31

specialized for uptake of molecules such as hormones in endocrine glands or for outflow of molecules such as in the kidney’s filtration system

Question 32

what is the function of lymphatic capillaries?

Answer 32

drain interstitial fluid produced when the plasma forced from the microvasculature by hydrostatic pressure does not all return to blood by the action of osmotic pressure

Question 33

how are lymphatic vessels formed?

Answer 33

by the merger of lymphatic capillaries, but their walls remain extremely thin