Cardiovascular 3

Question 1

Blood vessels

Where are nutrients and waste exchanged?

Answer 1

The capillaries

Question 2

Why do arteries and arteriols have thicker walls?

Answer 2

Theya rae closer to the heart and receive blood that is far greater pressure

Question 3

T/F: the lumen is bigger in arteries than in veins

Answer 3

False

Question 4

Why do veins appear less round in cross section?

Answer 4

Due to thinner walls, larger lumens, and reduced pressure

Question 5

What are the 3 layers of the blood vessel?

Answer 5

1. Tunica interna
2. Tunica Media
3. Tunica externa

Question 6

What makes up the tunica intima?

Answer 6

Epithelial and connective tissue layers

Question 7

What lines the tunica intima?

Answer 7

Endothelium

Question 8

Definition:

Binds the endothelium to the connective tissue

Answer 8

Basement membrane (basal lamina)

Question 9

Definition:

Internal elastic memebrane

Answer 9

Elastic fibres which provide structure and allow the artery to stretch/distend with the pulse pressure

Question 10

What is the thickest layer in arteries?

Answer 10

Tunica media

Question 11

What makes up the tunica media?

Answer 11

Layers of smooth muscle supported by elastic fibers arranged in circular sheets

Question 12

What regulates vasoconstriction and vasodilation of the circular muscles in the blood vessels?

Answer 12

Sympathetic fibres

Question 13

T/F: blood vessels further from the heart have more ealstic fibres

Answer 13

false!

the farther from the heart, the more smooth muscle so tone can change

Question 14

How is controlling BP like flappy bird?

Answer 14

When you have more sympathetic input (clicking) you get constriction. Removal of this input (stop clicking) blood vessles dilate

Question 15

What makes up the tunica externa?

Answer 15

Collagenous fibers with some elastic fibres

Question 16

What is the thickest layers in veins?

Answer 16

Tunica externa

Question 17

Where are elastic arteries found? Why here?

Answer 17

Closest to the heart

Allows for the vessels to expand as blood is pumped out of the heart and recoil after the surge has passed

Question 18

What are the arteries farther away from the heart with more smooth muscle called? What is the purpose of more smooth muscle?

Answer 18

Muscular arteries

Thick tunica media allows muscular arteries to play a role in vasoconstriction

Question 19

Why are arterioles so small?

Answer 19

To slow down or resist blood flow prior to entering the capillaries

Question 20

What is the primary role of arteriole?

Answer 20

Resistance and regulation of blood pressure

Question 21

What is the resting state of arterioles?

Answer 21

Slightly contracted

Question 22

Where does perfusion occur?

Answer 22

capillaries

Question 23

T/F: capillaries do not contain smooth muscles

Answer 23

True

Question 24

What is the most common type of capillary?

Answer 24

Continuous

Question 25

What characterizes continuous capillaries?

Answer 25

Endothelial lining with intercellular clefts which allow for exchange of water and other very small molecules between the blood plasma and interstitial fluid

Question 26

How do fenestrated capillaries differ from continuous capillaries?

Answer 26

Has fenestrations in addition to intercellular clefts

Question 26

What can be exchanged through continuous capillaries?

Answer 26

- metabolic products (glucose, water) - small hydrophobic molecules (O2, CO2) - hormones and leukocytes

Question 27

What type of molecules can pass through fenestrated capillaries?

Answer 27

Larger molecules like vitamines and urea

Question 28

What type of capillaries are commonly found in the SI and kidneys?

Answer 28

fenestrated capillaries

Question 29

What characterizes sinusoid capillaries?

Answer 29

They are flattened, and they have extensive intercellular gaps and incompleten basement memebranes in addition to intercellular clefts and fenestrations (looks like swiss cheese)

Question 30

What can pass through sinusoid capillaries?

Answer 30

largest of proteins inculding plasma proteins and cells

Question 31

What does slow blood flow through sinusoid capillaries allow for?

Answer 31

More time for excahnge to occur

Question 32

Where are sinusoids find?

Answer 32

- liver - spleen - bone marrow - lymph nodes - many endocrine (pituitary and adrenal glands)

Question 33

# Definition: Metarteriole

Answer 33

type of vessel that has structural characteristics of both an arteriol and a capillary

Question 34

What is the purpose of precapillary sphincters?

Answer 34

tightly regulate flow of blood from a metarteriole to the capillaries it supplies

Question 35

What is the normal state of precapillary sphincters?

Answer 35

closed

Question 35

How does blood flow when the precapillary sphincters are closed?

Answer 35

Blood will flow from the metarteriole directly into a thoroughfare channel and then into the venous circulation, bypassing the capillary bed entirely

Question 36

When do capillary sphincters open?

Answer 36

When the surrounding tissues need oxygen and have excess waste products

Question 37

Why are veins considered blood reservoirs?

Answer 37

systemic veins contain ~2/3 of total volume at any given time

Question 38

# Definition: Capacitance vesslels

Answer 38

Vessels that can distend readily to store high volume of blood even at low pressure such as veins

Question 39

How do water soluble substances diffuse in the capillaries?

Answer 39

Through intercellular clefts

Question 40

How do lipid soluble (steroids) and small non-polar (O2, CO2) substances substances diffuse in the capillaries?

Answer 40

Pass directly through the plasma membrane

Question 41

How do larger proteins (fibrinogen) and cells (blood cells) diffuse in the capillaries?

Answer 41

pass through intercellular gaps found in sinusoid capillaries

Question 42

# Definition: Transcytosis

Answer 42

Involves enclosing of substances within tiny vesicles which initially enter cells via endocytosis an then exit other side of cell via exocytosis

Question 43

# Definition: Mass movement of fluids to regulate the relative volumes of blood and interstitial fluids into and out of capillary beds

Answer 43

Bulk Flow

Question 44

What 2 pressure-driven mechanisms are involved in bulk flow?

Answer 44

- filtration - reabsorption

Question 45

# Definition (Bulk Flow) Volumes of fluid move from an area of higher pressure in a capillary to an area of lower pressure in the tissues

Answer 45

Filtration

Question 46

# Definition (Bulk Flow) Reabsorption

Answer 46

Movement of fluid from an area of higher pressue in the tissues to an area of lower pressure in the capillaries

Question 47

What 2 pressures drive bulk flow?

Answer 47

Hydrostatic pressure Osmotic Pressure

Question 48

# Definition: Force driving transport between the capillaries and the tissues due to the force that blood exerts within a blood vessles is greater than the pressure in the tissues, driving fluid out of the capillaries into the tissues

Answer 48

Hydrostatic pressure

Question 49

# Definition Osmotic Pressure

Answer 49

Net pressure that drives reabsorption (movement of fluid from interstitial fluid back into the capillaries) Draws fluid back in, driven by osmotic concentration gradients

Question 50

What are the key contributors to the osmotic concentration gradients?

Answer 50

Plasma proteins - albumin - alpha and beta globulins

Question 51

How does alubimin play a role in osmotic pressure?

Answer 51

Sodium is highly attracted to albumin so it passes trhough the membrane bring water with it into the capilaries (albumin stays in capillaries)

Question 52

# Definition: Starling's law of Capillaries

Answer 52

fluid movement due to fultration across the wall of a capillary is dependent on the blance between hydrostatic pressure gradient and the ostmotic pressure gradient across the capillary

Question 53

How much fluid filtered out at the capillaries through bulk flow is reasborbed in th venules? What happens to the rest?

Answer 53

85% excess fluid is picked up by capillaries of the lymphatic system