Section 8 - Exchange and transport in animals - Circulatory system - Blood, vessels, heart

Question 1

4 main things found in blood?

Answer 1

Red blood cells, white blood cells, platelets, plasma

Question 2

Job of red blood cells (erythrocytes)?

Answer 2

To carry oxygen from lungs to all cells in body

Question 3

Red pigment found in red blood cells and what it contains? Function of this?

Answer 3

Haemoglobin, which contains iron. In lungs, haemoglobin binds to O2 to become oxyhaemoglobin, but in body tissues, reversed so oxyhaemoglobin splits into haemoglobin and o2 to release O2 to cells

Question 4

2 structures of red blood cells and how does this help?

Answer 4

Biconcave disc shape to give large surface area for absorbing O2 and no nucleus to allow more room to carry O2

Question 5

Job of white blood cells?

Answer 5

To defend against infections

Question 6

2 types of white blood cells and what do each one do?

Answer 6

Phagocytes - change shape to engulf microorganisms called phagocytosis
Lymphocytes - produce antitoxins and antibodies against antigens on microorganisms

Question 7

Job of platelets?

Answer 7

To help blood clot

Question 8

Structure of platelets?

Answer 8

Small fragments of cells and have no nucleus

Question 9

Job of plasma?

Answer 9

Liquid that carries everything in blood: RBC, WBC, platelets, nutrients like glucose and amino acids, CO2, urea, hormones, proteins, antibodies and antitoxins

Question 10

3 types of blood vessels and function for each one?

Answer 10

Arteries - carry blood away from heart
Veins - carry blood to heart
Capillaries - involved in exchange of materials at tissues and supply food and O2 to cells, and take away waste like CO2

Question 11

3 structures of arteries and how this makes it designed for its function?

Answer 11

• Heart pumps blood at high pressure so strong, elastic and thick walls compared to size of hole down middle (lumen)
• Thick layers of muscle to make them strong
• Elastic fibres to allow them to stretch and spring back

Question 12

3 structures of capillaries and how this makes it designed for its function?

Answer 12

• Really small and narrow so can fit into gaps between cells, meaning they can carry blood close to every cell in body to exchange substances
• Permeable walls, to diffuse substances
• One cell thick walls to increase rate of diffusion by decreasing distance

Question 13

structures of veins and how this makes it designed for its function?

Answer 13

• Blood at lower pressure so thinner walls than artery
• Bigger lumen than arteries to help blood flow
• Valves to help keep blood flowing in right direction
• Smooth muscles and elastic fibres

Question 14

What type of circulatory system do mammals have?

Answer 14

Double circulatory system

Question 15

Explain how oxygen in blood is pumped around double circulatory system?

Answer 15

Heart pumps deoxygenated blood to lungs to take in O2. Oxygenated blood then returns to heart. Heart pumps oxygenated blood around all other organs of body to deliver O2 to cells, and then becomes deoxygenated, returning to heart.

Question 16

Name of 4 chamber in heart? Which in tricuspid and bicuspid sides?

Answer 16

Tricuspid: right atrium (top chamber), right ventricle (bottom chamber)
Bicuspid: left atrium (top), left ventricle (bottom)

Question 17

Name of 4 vessels that attach to heart?

Answer 17

Vena cava -> pulmonary artery

Pulmonary vein -> aorta

Question 18

Explain how blood is pumped through vessels and heart in the tricuspid/left side?

Answer 18

R-atrium receives deoxygenated blood from body through vena cava. Blood then moves through to r-ventricle. Tricuspid valve closes and semi-lunar valves open so heart contracts, pumping it to lungs through pulmonary artery

Question 19

Explain how blood is pumped through vessels and heart in bicuspid/left side?

Answer 19

L-atrium receives oxygenated blood from lungs through pulmonary vein. Blood then moves through to l-ventricle. Bicuspid valve closes and semi-lunar valves open so heart contracts, pumping it to body through aorta

Question 20

Which ventricle has a thicker wall and why?

Answer 20

Left ventricle has thicker wall and more muscle as it has to pump blood around whole body at high pressure, whereas right ventricle only has to pump blood to lungs

Question 21

Purpose of valves in heart?

Answer 21

To prevent backflow of blood in heart

Question 22

What is cardiac output?

Answer 22

The total volume of blood pumped by a ventricle every mintue

Question 23

Equation for cardiac output?

Answer 23

Cardiac output (cm³ min-1) = heart rate (beats per min) x stroke volume (cm³)

Question 24

What is heart rate?

Answer 24

Number of beats per minute

Question 25

What is stroke volume?

Answer 25

The volume of blood pumped by one ventricle each time it contracts