Blood Vessels

Question 1

Arteries
What do they consist mainly of?
Pressure?

Answer 1

Elastic, collagen and smooth muscle

Highest pressure, nearest to heart

Question 2

What are the layers of the artery?

Answer 2

Lumen
Endothelium 
Basement membrane 
Intima
Internal elastic lamina
Media
External elastic lamina
Adventitia

Question 3

What are the main 2 types of arteries?

Answer 3

Elastic

Muscular

Question 4

Elastic arteries
Location?
Function?
Structure?

Answer 4

Aorta, closer to heart

Need to withstand great pressures & maintain constant pressures by quick elastic recoil

More elastic tissue in tunica media, larger lumen

Question 5

Muscular arteries
Location?
Function?
Structure?

Answer 5

Distal to heart

More muscle for vasoconstriction/dilation regulation

More muscular tissue in tunica media, smaller lumen

Question 6

What are arterioles and their function?

Answer 6

Bridge between arteries and capillaries
Arterioles - 3 or less muscle layers in tunica media
Site of most resistance (contribute most to total peripheral resistance)

Question 7

What do veins hold and responsible for?

Answer 7

Hold 70% total blood volume

Responsible for end diastolic volume - veins drain blood from rest of body to the heart

Question 8

Veins return blood to the heart by what 3 mechanisms?

Describe them

Answer 8

Skeletal muscle contraction - exercise

Resp pump muscles need blood

Peristalsis (squeezing of food down GI tract) (Smooth muscle contraction in GI tract needs blood)

Question 9

Capillaries
Speed of flow?
Regulated by?

Answer 9

Slow flow to increase nutrient exchange

Precapillary sphincters

Question 10

What are the 3 types of capillaries?

Answer 10

Continuous
Fenestrated
Discontinuous

Question 11

Describe continuous capillaries

Answer 11

Fully intact endothelium + basement membrane

Tiny molecules pass through (ions)

Question 12

Describe fenestrated capillaries?

Answer 12

Endothelial gaps, basement membrane intact
Larger molecules (glucose + AA)

Question 13

Describe discontinuous capillaries?

Answer 13

Huge endothelial gaps, incomplete BM (whole RBC)

Found in kidneys, liver, spleen

Question 14

Describe the pulmonary circulation pathway

Answer 14

Blood leaves the right ventricle via a single large artery, the pulmonary trunk, which divides into the two pulmonary arteries, one supplying the right and one supply the left lung.
In the lungs the arteries continue to branch and connect to arterioles, leading to capillaries that unite into venules and then veins. The blood leaves the lungs via four pulmonary veins, which empty into the left

Question 15

What is BP in pulmonary vessels?

Why?

Answer 15

25/8
Thin walled
Prevents oedema - Too high pressure means fluid squeezed out down hydrostatic pressure gradient

Question 16

What happens in pulmonary vessels in hypoxia?

Answer 16

Vasoconstriction, less blood flow to areas less ventilated

Question 17

Describe systemic circulation pathway?

Answer 17

Blood leaves the left ventricle via single large artery, the aorta. The arteries of the systemic circulation branch off the aorta, dividing into progressively smaller vessels. The smallest arteries branch into arterioles, which branch into roughly 10 billion very small vessels, the capillaries, which unite to form larger-diameter vessels known as venules. The arterioles, capillaries & venules are collectively referred to as the MICROCIRCULATION. The venules then unite to form larger vessels, veins. The veins from the various peripheral organs and tissues unite to produce two large veins, the inferior and superior vena cava which drain into the right atrium

Question 18

What is the BP is systemic vessels? Why?

Answer 18

120/80

Thick walled

Question 19

What happens in systemic vessels in hypoxia?

Answer 19

Vasodilation- increased blood flow to deficient tissue