cardiovascular

Question 1

Elastic arteries

Answer 1

aorta and branches

• thick intima
• thick media: collagen and elastic fibres
• thin adventitia: vasa vasorum- blood vessels which nourish the arterial wall.

Question 2

Muscular arteries

Answer 2

vasoconstriction and vasodilation

• intima: collagen and elastic fibres
• main feature: internal elastic laminar
• thick media: SM
• adventitia: thinner than media, collagen

Question 3

Arterioles

Answer 3

regulators of blood flow and BP

• thin intima
• thick media- SM
• fairly prominent adventitia

Question 4

Metaterioles (precapillaries)

Answer 4

• are sphincters which control the amount of blood flow into the capillary beds
• interposed between arterioles and capillaries

Question 5

capillaries

Answer 5

• sites of O2 and CO2 exchange
• no muscular or connective tissue coats (endothelial lined tubes)
• continuous: endothelial cell lined by cell junctions
• fenestrated: intestinal villi and golmeruli of kidney
• discontinuous: spleen, bone marrow and liver

Question 6

Large Veins

Answer 6

vena cavae

• thick intima
• poorly developed media
• adventitia: long. SM

Question 7

Medium veins

Answer 7

• thin intima
• valves are found in the extremities
• relatively thin media
• well developed adventitia

Question 8

Venules

Answer 8

• intima: continuous with endothelium with thin basal laminar
• thin media: a few SM fibres

Question 9

Artriovenous Anastamoses (A-V Shunts)

Answer 9

alternate channels that allow blood to pass directly from arterioles to venules, bypassing capillary beds
- found on skin of fingertips, toes and face

Question 10

Epicardium

Answer 10

• flat, mesothelial cells
• also known as visceral pericardium (inner layer of serious pericardium. The outer is parietal pericardium)
• embedded here are coronary arteries, veins, lymphatics, nerves and ganglia.

Question 11

myocardium

Answer 11

• bundle of cardiac fibres and purkinje fibres (found of the innermost part of the myocardium next to the endocardium)
• generate nervous impulses to conduct them through the myocardium

Question 12

Endocardium

Answer 12

3 layers:

1. layer of endothelium and loose collagen
2. layer of elastic fibres and a few SM fibres
3. subendocardial zone of loose CT tissue vessel, nerves and scattered purkinje fibres

Question 13

Valves of the Heart

Answer 13

1. tricuspid- near RA and RV
2. pulmonary semilunar
3. aortic semilunar
4. bicuspid or mitral- near LA and LV
   all have 3 triangular valves except for mitral

Question 14

Lymph vascular system

Answer 14

• system for fluid (lymph-blood filtrate from plasma that has escaped from capillaries into the interstitial
  spaces) to flow back to the heart- only flow in 1 direction
• contain lymphocytes and fat droplets
• lymph is filtered by phagocytosis