Circulation

Front 1

Layers of arteries

Back 1

The inner layer is the tunica interna, the middle layer is the tunica media, and the outer layer is the tunica externa.

Front 2

vaso vasorum

Back 2

Large arteries are themselves supplied with blood vessels that nourish their thick walls called

Front 3

3 classes of arteries

Back 3

1. elastic arteries
2. muscular arteries
3. arterioles

Front 4

Elastic arteries

Back 4

Are large arteries leading directly from the heart (aorta and pulmonary arteries) and are sometimes referred to as conducting arteries because they conduct blood directly from the heart to the muscular arteries.

Front 5

Elastic arteries

Back 5

Their middle layer contains a large amount of elastic tissue that permits the artery to expand as the blood is pumped in from the heart (and to passively contract when the cardiac contraction ceases).

Front 6

Muscular arteries

Back 6

Are of medium size, with a middle coat that is chiefly muscular, and are often called distributing arteries because they distribute blood to various organs.

Front 7

When muscular arteries' walls contract or relax...

Back 7

vasoconstriction
vasodilation

Front 8

Are also muscular arteries but of a much smaller size.

Back 8

Arterioles

Front 9

Anastomosis

Back 9

Arteries branch and rebranch many times.
Sometimes they rejoin, called an anastomosis.

Front 10

Anastomosis is the communication of..

Back 10

any blood vessel, not just arteries.

Front 11

collateral circulation

Back 11

Anastomoses provide alternate pathways for blood to reach any given tissues

Front 12

Capillaries

Back 12

Are thin-walled vessels that connect arterioles to venules

Front 13

each arteriole branches into many capillaries so that

Back 13

a capillary network or bed is formed

Front 14

The walls of capillaries consists of a single layer of

Back 14

endothelial cells

Front 15

loosely joined so that some substances may easily pass between the cells, even white blood cells can force their way between (RBCs & the proteins normally do not leave the capillaries though).

Back 15

Walls of capillaries

Front 16

3 types of capillaries

Back 16

1. Continuous
2. Fenestrated
3. Sinusoids

Front 17

Describe each type of capillary...

Back 17

Continuous - the endothelial cells form an uninterrupted lining.
2) Fenestrated - have minute pores in the lining, which permit an even greater movement of molecules to and from the capillary.
3) Sinusoids - have a larger diameter, though their walls are the same thickness, are found in the liver, bone marrow, and adrenal glands.

Front 18

Veins are thinner because..

Back 18

they contain lesser amounts of elastic and muscle tissue.

Front 19

Which two factors assist in movement of blood through the veins?

Back 19

1. valves
2. muscular contractions

Front 20

Valves

Back 20

semilunar folds of the internal coat of veins and usually consist of two flaps

Front 21

Muscular contractions

Back 21

various movements, breathing, walking, etc. apply pressure to the veins and help to push blood through them

Front 22

systemic circulation will always begin with the..

Back 22

aorta

Front 23

Aorta

Back 23

arises from the left ventricle and arches backward, descending to the left.

Front 24

CVA, or Cerebrovascular Accident

Back 24

sudden interruption of blood flow to a portion of the brain (usually occlusion or rupture of a cerebral blood vessel).

Front 25

is the volume of blood moving past a particular point in the circulation in a given amount of time (as in milliliters per minute).

Back 25

flow

Front 26

is force per unit area exerted on the wall of a blood vessel by its contained blood.

Back 26

pressure

Front 27

is the force that tends to oppose the flow (the amount of friction blood encounters as it passes through the vessels).

Back 27

resistance

Front 28

equation for blood flow

Back 28

change in pressure/resistance

Front 29

equation for blood pressure

Back 29

cardiac ouptut x resistance

Front 30

blood pressure is generated by...

Back 30

the contraction of the ventricles pushing blood through the vessels.

Front 31

blood pressure is highest in the...

Back 31

aorta

Front 32

blood pressure is lowest in the..

Back 32

vena cavae (80)

Front 33

What is the heart doing during systole?

Back 33

contracting

Front 34

what is the heart doing during diastole?

Back 34

relaxing

Front 35

may rise or fall due to vasoconstriction or vasodilation

Back 35

Peripheral resistance

Front 36

Baroreceptors

Back 36

are nerve endings in vessel walls that are sensitive to vessel stretching (are found in the carotid sinus, [an area of the common carotid artery near where it branches into the external and internal carotids] and in the walls of the aortic arch

Front 37

Baroreceptors send signals to the...

Back 37

medulla oblongata

Front 38

chemoreceptors

Back 38

are responsive to the concentrations of oxygen and carbon dioxide, are also found in the aortic arch and carotid arteries

Front 39

autonomic nervous system has two centers..

Back 39

1. vasomotor center
2. cardiac center

Front 40

adjusts the force and rate of heart contractions.

Back 40

cardiac center

Front 41

regulates blood pressure by acting on the smooth muscle in the walls of blood vessels (vasoconstriction and vasodilation).

Back 41

vasomotor center

Front 42

adrenal medulla hormones that regulate blood pressure

Back 42

epinephrine (increases cardiac output) and
norepinephrine (vasoconstrictor).

Front 43

atrial natriuretic

Back 43

- a hormone produced by the
atria, it reduces blood volume and blood
pressure

Front 44

The kidneys release renin, an enzyme that causes the formation of..

Back 44

angiotensin (vasoconstrictor to regulate blood pressure)

Front 45

Circulatory shock

Back 45

insufficient cardiac output resulting in inadequately filled blood vessels (fainting initiates increasing blood flow to the brain).

Front 46

Carries out exchange function in blood

Back 46

capillaries

Front 47

precapillary sphincters,this band of smooth muscle acts as a valve

Back 47

The entry of blood into capillaries is controlled by the...

Front 48

The concentration of nutrients and oxygen is always highest in the blood, because..

Back 48

once they have passed into the tissue fluid, they are taken up and metabolized by the tissue cells.

Front 49

What happens in cellular respiration?

Back 49

The cells utilize oxygen and glucose

Front 50

What do cells utilize in protein synthesis?

Back 50

amino acids

Front 51

Following cellular respiration, the cells..

Back 51

give off carbon dioxide, water, and wastes.

Front 52

Since tissue fluid is always the area of greater concentration for these waste materials they...

Back 52

diffuse into the capillaries

Front 53

Blood moving in a capillary exerts two kinds of pressure:

Back 53

1. blood hydrostatic pressure
2. osmotic pressure

Front 54

osmotic pressure

Back 54

is the pressure caused by large molecules in the blood (osmotic pressure doesn't vary much along the capillary, is about 26 mm Hg).

Front 55

blood hydrostatic pressure

Back 55

- is the blood pressure, the pressure that remains from the constant pumping of the heart.

Front 56

By the time it reaches the arterial end of the capillary, the hydrostatic pressure is about how much?

Back 56

35 mm Hg

Front 57

by the time the blood reaches the venous end of the capillary the hydrostatic pressure has dropped to about

Back 57

16 mm Hg

Front 58

osmotic pressure hangs around how much?

Back 58

26 mm Hg

Front 59

At the arterial end of a capillary, what happens to the blood pressure?

Back 59

the blood pressure is higher than the osmotic pressure, and therefore water, oxygen, amino acids, and glucose leave the bloodstream (and enter the tissue fluid, then the cells).

Front 60

At the venous end of the capillary,

Back 60

blood pressure is reduced, but there is no reduction in osmotic pressure, which tends to pull fluid into the capillary.