The Heart, Blood And Vessels

Question 1

Why do we have two transport systems?

Answer 1

• Pulmanory circulation - transports blood from heart to lungs and back to exchange O₂ and CO₂ with air
• Systemic circulation - transports blood from heart to body as back to exchange O₂ and CO₂ with body cells

Question 2

What do veins and arteries do?

Answer 2

Veins take blood to the heart

Arteries take blood away from the heart

Question 3

Order of circulatory system

Answer 3

vena cava -> right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> left ventricle -> aorta -> body -> vena cava

Question 4

What happens during diastole?

Answer 4

• heart muscles relaxing
• valves closed
• blood flows into atria

Question 5

What happens during atrial systole?

Answer 5

• atria contract
• valves open
• blood flows into ventricles

Question 6

What happens during ventricular systole?

Answer 6

• ventricles contract
• valves close
• blood flows out of ventricles

Question 7

What can affect heart rate?

Answer 7

• Exercise
- muscles need more energy
- more oxygen and glucose needed
- heart rate and force of beat (affects stroke volume) increases
• Stress (anger, fear) 
- 'fight or flight' response

Question 8

How is the heart rate controlled?

Answer 8

• Osmoreceptors in aorta sense CO₂ levels
• Cardiac centre in brain receives information via sensory nerve
• Cardiac centre sends nerve in pluses via accelerator or decelerator nerves
• Pacemaker reacts and increases (or decreases) heart rate and five of heart beat -> blood pressure increases (or decreases)

Question 9

What are the effects of adrenalin on heart rate?

Answer 9

• Adrenalin released from the adrenal glands stimulates the pacemaker to increase heart rate

Question 10

What is coronary heart disease?

Answer 10

• Blockage of coronary artery
• Blood supply to area of heart muscle cut off
• Less oxygen and glucose reaches heart muscle
• Area of heart muscle cannot respire -> heart arrack

Question 11

What is the largest artery in the body?

Answer 11

Aorta

Question 12

How does the blood in the left side of the heart differ from the blood in the right side of the heart?

Answer 12

• it contains less CO₂

* under higher pressure

Question 13

What do arteries do?

Answer 13

Bring (oxygenated) blood from heart to body

Question 14

What is the blood pressure in an artery?

Answer 14

High

Question 15

What is the blood like in arteries?

Answer 15

• oxygenated

* bright red

Question 16

What is the structure and diameter of an artery?

Answer 16

• thick, elastic, muscular wall
• small lumen
• diameter - 1mm

Question 17

Are there valves in arteries?

Answer 17

No

Question 18

What are the components of the circulatory system?

Answer 18

Heart - pump
Blood vessels - transport route
Blood - transport medium

Question 19

What do veins do?

Answer 19

Bring (deoxygenated) blood from body to heart

Question 20

What is the blood pressure in a vein?

Answer 20

Low

Question 21

What is the structure and diameter of a vein?

Answer 21

• thin wall
• large lumen
• diameter - 0.5mm

Question 22

Are there valves in veins?

Answer 22

Yes

Question 23

What is the blood like in a vein?

Answer 23

Deoxygenated, deep purple-red

Question 24

What do capillaries do?

Answer 24

Link between arteries and veins for exchange of material between blood and cells

Question 25

What is the blood pressure in a capillary?

Answer 25

Medium

Question 26

What is the structure and diameter of capillaries?

Answer 26

* very thin wall (one layer of cells) * very small liken (red blood cells travel single file) * diameter - 0.5µm (micrometer)

Question 27

What do valves do?

Answer 27

Prevent the backflow of blood

Question 28

Why do arteries have muscular walls?

Answer 28

Higher pressure - must be stronger

Question 29

Why is injuring an artery more dangerous than injuring a vein?

Answer 29

Higher pressure - more blood is flowing

Question 30

Why are capillary walls only 1 cell layer thick?

Answer 30

Short diffusion distance?

Question 31

Which one is the only artery that doesn't look bright red?

Answer 31

Pulmanory artery

Question 32

What is blood composed of?

Answer 32

* Plasma (55%) * White blood cells + platelets (1%) * Red blood cells (44%)

Question 33

What is plasma?

Answer 33

``` Liquid part of the blood • Made of: - antibodies + protein - water (90%) - CO₂ + urea (waste) - mineral ions \ - glucose | -nutrients - amino acids / - hormones - clotting factors - heat energy ```

Question 34

What are leukocytes (white blood cells)?

Answer 34

Defence against disease • phagocytes - ingest pathogens • lymphocytes - produce antibodies

Question 35

What are platelets (thrombocytes)?

Answer 35

Involved in blood clotting

Question 36

What are erythrocytes (red blood cells) and their adaptations?

Answer 36

``` Oxygen transport from lungs to cell • Haemoglobin - transport of oxygen - haemoglobin + O₂ ⇌ oxyhemoglobin • No nucleus - more space for haemoglobin • Biconcave shape - large SA/V ratio - short diffusion distance • Thin membrane - short diffusion distance ```

Question 37

What is the blood like in a capillary?

Answer 37

Both types (deoxygenated and oxygenated).

Question 38

How does doing exercise affect heart rate?

Answer 38

Heart rate increases exercise, because more energy is needed so respiration increases. Respiration increases the amount of carbon dioxide in the blood, which is detected by receptors (in the aorta and carotid artery). The receptors send signals to the brain to increase the heart rate.

Question 39

Which blood vessel (in the heart) contains blood at the highest pressure?

Answer 39

The aorta (bringing oxygenated blood to the body).