Blood Vessels

Question 1

Where does the intracellular and extracellular fluid lie?

Answer 1

Question 2

Describe the pressure at the arterial end of capillary beds

What does it favour?

Answer 2

• Relatively high hydrostatic, relatively low oncotic capillary pressure
  
  • favours filtration (delivery)

Question 3

Describe the pressure at the venous end of capillary beds

What does it favour?

Answer 3

• Relatively low hydrostatic, high oncotic capillary pressure
  
  • Favours reabsorption

Question 4

What are the 4 Starling forces?

Answer 4

1. Capillary hydrostatic pressure (filtration)
2. Plasma colloid osmotic pressure (reabsorption)
3. Interstitial hydrostatic (reabsorption)
   
   • Except in lungs due to lymphatics
4. Interstitial colloid osmotic (filtration)

Question 5

What are the 3 layers of blood vessel?

Answer 5

1. Tunica intima
2. Tunica media
3. Tunica adventitia

Question 6

What is found in the tunica intima?

Answer 6

• Thin endothelial layer
• Few SM fibres

Question 7

What is found in the tunica media?

Answer 7

• Very thick layer of a lot of smooth muscle cells
• Abundant extracellular matrix- collagen, proteoglycans, elastin

Question 8

What is found in the tunica adventitia?

Answer 8

• CT, fibroblasts, mast cells etc.
• Nerves
• Blood vessels - vasa vasorum

Question 9

What does stimulation of Alpha1 adrenergic receptors cause

Answer 9

Vasoconstriction

Question 10

On what vessels are Beta 1 and 2 receptors located?

Answer 10

On the smooth muscle segments of coronary vessels

Question 11

What does stimulation of B1 and 2 AR cause

Answer 11

vasodilation

Question 12

What is an Aneurysm?

Answer 12

Excessive localised swelling of the artery

Question 13

What are the 3 types of Aneurysms?

Answer 13

Question 14

What are the 2 types of arteries?

Answer 14

1. Elastic (closest to heart)
2. Muscular

Question 15

What is the significant feature of elastic arteries and what are 3 resulting functions?

Answer 15

• High amounts of elastin
  1. Withstand the pressure of ejection from the ventricles → hence prevents over expansion
  2. Helps buffer the pulsatile ejection of blood from the heart so it has a more even flow
  3. The elastic recoil also helps move blood forward into the rest of the circulatory system

SM oposes stretch to maintain integrity

Question 16

Muscular arteries are vasoactive

What does this mean?

Answer 16

Means they are capable of:

• Vasodilation (through beta1 adrenergic receptors)
• Vasoconstriction (through smooth muscle bracelet contraction).

This helps modulate blood pressure and blood flow

Question 17

What factors control vascular smooth muscle?

Answer 17

1. Membrane potential
2. Hormones
3. Myogenic mechanism

Question 18

How does membrane potential affect vascular smooth muscle

Answer 18

Question 19

How do hormones affect vascular smooth muscles

Answer 19

Question 20

How does the myogenic mechanism affect vascular smooth muscle?

Answer 20

1. Stretch of vessel wall
2. Opens mechanical Ca2+ gates
3. Contraction of vessel wall

Question 21

What are the 3 different types of capillaries

Answer 21

1. Continuous
2. Fenestered
3. Sinusoid

Question 22

What are the characteristic features of continuous capillaries?

Answer 22

• Tight jucntions between endothelium
• Only some small solutes pass through intercellular clefts
• e.g. the blood brain barrier, retina and testis)