Characteristic Features Of Blood Vessels

Question 1

What do all blood vessels have?

Answer 1

• thin and smooth layer of endothelium
• reduces friction and gives a smooth flow

Question 2

What is the role of elastic tissue or elastin?

Answer 2

withstands pressure

Question 3

What is the role of smooth muscle tissue?

Answer 3

strengthening

Question 4

What is the role of collagen?

Answer 4

protection

Question 5

What is the role of a lumen?

Answer 5

maintains pressure

Question 6

What do arteries do and describe the pressure?

Answer 6

• arteries transport blood from heart to organs
• blood is under high pressure

Question 7

Describe the structure of arteries

Answer 7

• thick walls to withstand high pressure
• narrow lumen to increase pressure
• many elastin fibres to withstand high pressure during pulsation
• outer wall of fibrous proteins to support + strengthen wall to resist damage due to high bp

Question 8

What do capillaries do and describe the pressure?

Answer 8

• involved in exchange of materials between blood and the tissue cells e.g. oxygen
• site of diffusion
• blood is under low pressure

Question 9

Describe the structure of capillaries

Answer 9

• one cell thick endothelial layer (thin wall) to increase diffusion
• narrow lumen and large number of capillaries to create greater friction + high s.a to reduce bp and blood flow passing thru

Question 10

What do veins do and describe the pressure?

Answer 10

• these carry blood back to the heart from the tissues
• blood is under lowest pressure

Question 11

Describe the structure of veins

Answer 11

• large lumens to give low resistance + low bp
• thin walls as bp is low as all blood is going back to heart
• thin elastic layer as bp is low + wall doesnt need to stretch or recoil
• has semi lunar valves to squeeze blood by skeletal muscles contracting back up to the heart + to stop backflow ensuring blood passes in one direction

Question 12

Describe the pressure in the arteries

Answer 12

• flow is fast
• pressure is high + fluctuating
• due to contraction of left ventricle

Question 13

Describe the pressure in the capillaries

Answer 13

• increased cross sectional area
• causing increased friction
• this reduces bp
  -flow changes from pulsar to smooth and slows down

Question 14

Describe the pressure in the veins

Answer 14

• pressure is low
• flow is smooth and slow