7.3: Circulatory system of a mammal

Question 1

What type of system?

Answer 1

a mass transport system

Question 2

Multicellular organisms

SA:V ratio

Answer 2

low SA:V ratio

Question 3

Circulatory system

Answer 3

specialised transport system that carries raw materials from specialised exchange organs to their body cells

Question 4

Circulatory system made up of

Answer 4

heart and blood vessels

Question 5

Blood transports

Answer 5

respiratory gases, products of digestion, metabolic wastes and hormones

Question 6

Coronary arteries

Answer 6

supply the heart with blood

Question 7

Double circulatory system

Answer 7

blood passes through the heart twice in one circuit

Question 8

Arteries
characteristics in relation to functions
2

Answer 8

thick and muscular walls with elastic tissue to stretch and recoil = maintain high pressure
endothelium is folded = allows it to stretch and helps maintain high pressure

Question 9

Arterioles

Answer 9

A network of smaller vessels throughout the body.

Question 10

Arterioles

function

Answer 10

Muscles inside the arterioles direct blood to areas of high demand by contracting or relaxing.

Question 11

Veins

characteristics in relation to functions

Answer 11

wider lumen, little elastic and muscle tissue = lower pressure
contain valves = prevents back flow of blood
body muscles around veins contract = to help blood flow

Question 12

Arterioles branch into

Answer 12

capillaries

Question 13

Capillaries

info.

Answer 13

one cell thick
adapted for efficient diffusion
found near cells in exchange tissues = short diffusion pathway
large number of capillaries = increase SA for exchange

Question 14

Networks of capillaries in tissue

Answer 14

capillary beds

Question 15

Tissue fluid is formed from

Answer 15

the blood

Question 16

Tissue fluid

Answer 16

the fluid that surrounds cells which is made from small molecules that leave the blood plasma

Question 17

Pressure filtration

Answer 17

substances move out of capillaries into the tissue fluid in the capillary bed

Question 18

Pressure filtration

overview

Answer 18

at start of capillary bed = hydrostatic pressure inside capillaries is greater than in tf.
difference in hydrostatic pressure = fluid forced out into spaces around cells forming tf.
this reduces hydrostatic pressure in capillaries = hydrostatic pressure lower at venule end
water potential lower at venule end too
water re-enters capillaries from tf. by osmosis

Question 19

Excess fluid from tissue fluid

Answer 19

drained into the lymphatic system

Question 20

Lymphatic system

Answer 20

a network of tubes which transports the excess tf. and drains it back into the circulatory system