L21 Blood vessels structure and function

Question 1

structure of normal blood vessels

Answer 1

3 concentric layers
Intima
Media
Adventitia

Question 2

Describe the Intima

Answer 2

inner most layer
Thin ECM composed of collagen
Endothelial monolayer
Bordered by internal elastic lamina

Question 3

Describe the media

Answer 3

Allows vessels to contract and dilate according to BP
Smooth muscle cells-pericytes secrete a specific ECM
Bordered by external elastic lamina

Question 4

Describe the Adventitia

Answer 4

Loose connective tissue
Sympathetic nerve tissue
Vasa Vasorum

Question 5

Function of vascular muscular smooth cells

Answer 5

• Maintain blood vessel integrity
• Support endothelium
• Control blood flow through contraction and dilation (ANGT2)
• Synthesise ECM
• Secrete growth factors (VEGF)
• Usually do not divide but under stress/in response to injury can divide

Question 6

Describe vascular injury

Answer 6

endothelial cell dysfunction/ loss- intima

• Stimulates smooth muscle cell recruitment, proliferation and matrix synthesis
• Damaged endothelium is repaired by migrating endothelial cells and circulating precursor cells
• Repaired intima is composed of endothelial cells, smooth muscle cells and ECM

Leads to intimal thickening

• Impeded vascular flow
• Weakened vessel wall

Question 7

Types of hypertension

Answer 7

• Benign/mild

- Malignant/accelerated/severe death < 2yrs

Question 8

Pathology of mild hypertension in the heart

Answer 8

hypertrophy

Cardiac myocytes are terminally differentiated-will not divide

Question 9

Pathology of mild hypertension in the kidney

Answer 9

renal disease
• Benign hypertension- arterionephrosclerosis (thickening and hardening of blood vessels in the kidney)
• Hyaline thickening of small arteries and arterioles-hyaline/arteriolosclerosis

Question 10

Pathology of mild hypertension in the Brain

Answer 10

• Injury to the brain bc of altered blood flow ischemic or haemorrhagic
Cerebrovascular disease

Question 11

Pathology of mild hypertension in the Retina

Answer 11

• Haemorrhages
• Exudates ( swollen ischemic retinal neurons)
• Microaneurysm

Question 12

Consequences of severe hypertension

Answer 12

Brain
• Encephalopathy: disease affecting function of brain
• Oedema
• Haemorrhages

Kidney
• Rapidly progressive renal failure

Retina
• Flame haemorrhages
• Papilloedema: optic swelling due to intracranial pressure
• Cotton wool spots (ischemic/infarcted retina)

Vessels
• Aneurysm rupture : enlargement of blood vessels
• Dissecting aneurysms