The Circulatory System

Question 1

Describe the structure of an artery

Answer 1

Thick muscular walls - constricts and dilates to control volume of blood flow

Elastic tissue - stretches during systole
recoils during diastole to help maintain high pressure and smooths pressure surges

Question 2

What is the difference between a regular artery and the pulmonary artery?

Answer 2

All arteries carry oxygenated blood away from the heart but pulmonary artery carries deoxygenated

Question 3

Describe the structure of a vein

Answer 3

Thin muscle tissue
Thin elastic tissue - low pressure won’t cause them to burst / won’t create recoil action
Contains valves - prevents back-flow of blood
Wider lumen

Question 4

Describe the difference in pressure in the artery and the vein

Answer 4

Arteries carry blood away from the heart at a high pressure
Endothelium is folded allowing artery to stretch to maintain pressure

Veins carry blood to the heart at a lower pressure
Blood flow is helped by contraction of surrounding muscles

Question 5

What is the difference between a regular vein and the pulmonary vein

Answer 5

All veins carry deoxygenated blood to the heart but pulmonary carries oxygenated to the heart from the lungs

Question 6

Describe the structure of capillaries

Answer 6

Found very near cells in exchange tissues
Walls one cell thick
Lumen is narrow (squashed RBCs flat)
= short diffusion pathway
Numerous and branched - increases SA for exchange

Question 7

How is tissue fluid formed

Answer 7

• High hydrostatic pressure at arteriole end
• causes overall outward pressure forcing fluid out into spaces surrounding cells
• tissue fluid formed
• fluid leaves reducing hydrostatic pressure in capillaries (h.p lower at venule end)
• fluid loss and increasing conc. of proteins = lower w.p at venule end than w.p in the tissue fluid
• water outside is reabsorbed back via osmosis

Question 8

Describe large blood vessels in a mammal

Answer 8

Aorta - carries blood at high pressure to the whole body

Hepatic artery - short blood vessel carrying oxygenated blood to liver under high p.

Hepatic portal vein - carries blood from small intestine to liver under low p.

Hepatic veins - carry blood from liver to superior vena cava (heart) at lowest p.

Renal artery - carries blood away from heart to kidneys

Renal vein - carries blood from kidneys back to heart

Question 9

Structural differences between artery and vein

Answer 9

Artery - layer of thicker muscle / elastic tissue

Veins - contain valves
- wider lumen

Question 10

What happens to tissue fluid that isn’t reabsorbed back into the capillaries

Answer 10

drained of their contents in the lymphatic system and returned back into bloodstream