Circulatory System

Question 1

Circulatory system

Answer 1

Transport system for the body. It carries the following:
»Oxygen »Nutrients »Carbon dioxide »Waste

Question 2

Glucose

Answer 2

From digestive system
Necessary for respiration / cell functions

Question 3

Oxygen

Answer 3

From inhaled air in the lungs
Necessary for respiration

Question 4

Carbon Dioxide

Answer 4

From Cellular respiration
Needs to be exhaled via the lungs
Waste
From bodily processes
Needs to be excreted via the lungs, skin, kidneys…

Question 5

Components of Blood

Answer 5

Plasma
Red blood cells
White blood cells
Platelets
System of tubes
Arteries
Veins
Capillaries
THE HEART

Question 6

Plasma

Answer 6

• Liquid part of the blood
• Pale yellow – mostly water

Question 7

Plasma function

Answer 7

to transport chemicals and heat

Also carries the red blood cells, white blood cells, and platelets.

Question 8

Red Blood Cells

Answer 8

Round, flattened discs, curve inward near centre
• Small, no nucleus, formed in bone marrow
• Very numerous – approx 5million per drop bloo

Question 9

Red Blood Cells function

Answer 9

transport oxygen to cells

Question 10

White Blood Cells

Answer 10

• Larger than Red Blood Cells but fewer in number
• No definite shape – shape can change
• They are also made in the bone marrow

Question 11

White Blood Cells function

Answer 11

to fight infection

Question 12

Platelets

Answer 12

• Smaller than red or white blood cells
• They are formed in the bone marrow
• They are formed from larger cells breaking down into pieces

Question 13

Platelets function

Answer 13

help to form blood clots

Question 14

System of Tubes + Pump (pump= heart)

Answer 14

• These tubes are called blood vessels
• They come in three main types:
– Arteries
– Veins
– Capillaries

Question 15

Arteries

Answer 15

• Carry blood AWAY from the heart
• Flow of blood is strong and at high pressure
• Artery walls are thick and strong to withstand this pressure
All arteries (except pulmonary artery) carry oxygenated blood

Question 16

Veins

Answer 16

• Carry blood BACK to the heart
• Flow of blood is weaker and pressure is low
• Vein walls are thinner and weaker than artery walls
• Pressure is low, so there is a danger of backward flow of blood, especially when flow direction is against gravity

Question 17

The Heart

Answer 17

• Is an organ about the size of a clenched fist
• Function: pumps blood around the body
• It pumps blood by contracting periodically
• Cardiac muscle provides the contraction

Question 18

Pulse Rates

Answer 18

• When the heart contracts, it squeezes blood into the arteries under pressure.
• As blood flows down the arteries, surges of pressure can be felt where the arteries are close to the surface

Question 19

Two Blood Circuits

Answer 19

• The human circulatory system has what is known as Double Circulation
• Blood passes through the heart twice on its journey around the body

• 1: Pulmonary Circulation
– Blood leaves the heart
– goes to the lungs to become oxygenated
– returns to the heart

• 2: Systemic Circulation
– Blood leaves the heart
– travels to other parts of the body – returns to the heart

Question 20

Structure of the Heart

Answer 20

• The heart is split down the middle into two sides by the septum
• Each side has an upper chamber called an atrium (plural atria)
• Each side also has a lower chamber called a ventricle.
• This makes a total of 4 chambers
• Valves between the upper and lower chambers ensure that blood only flows in one direction

Question 21

Left versus Right Of the Heart

Answer 21

• Heart diagrams are always shown as if facing the person
• The left side of the heart appears on the right of the diagram, and vice versa
• The left side of the heart always pumps oxygenated blood (shown in red), received from the lungs, and pumps it to the body.
• The right side always pumps deoxygenated blood (shown in blue), received from the body, and pumps it to the lungs

Question 22

Blood Vessels of The Heart

Answer 22

• The vena cava (veins) bring blood from the body into the right atrium.
• The right ventricle pumps blood into the pulmonary artery, which leads to the lungs.
• The pulmonary vein returns blood from the lungs to the left atrium.
• The left ventricle pumps blood into the aorta (an artery) which leads to all other parts of the body.
• Both the pulmonary artery and the aorta have valves at the base to prevent blood flowing back into the heart.