Section 5 - Blood and Organs

Question 1

Blood components

Answer 1

• plasma
• platelets
• red blood cells
• white blood cells

Question 2

Plasma

Answer 2

Plasma carries
- Red, white blood cells and platelets.
- Digested food products
- Carbon dioxide
- Urea
- Hormones
- Heat energy

Question 3

Red blood cells

Answer 3

• Transport oxygen
• Small and biconcave shape to give a large surface area
• Contain haemoglobin which contains lots of iron
• Red blood cells dont have a nucleus

Question 4

Two different white blood cells:

Answer 4

• Phagocyte
• Lymphocytes

Question 5

Phagocytes

Answer 5

• They detect things that are ‘foreign’ to the body. They then engulf and digest them
• They are non-specific

Question 6

Lymphocytes

Answer 6

• Pathogens have unic antigens on its surface
• When lymphocytes encounter them they start to produce proteins called antibodies. These are specific to the antigens
• Antibodies produced rapidly
• Memory cells are lastly produced to remember the specific antigen.

Question 7

Three type of blood vessels

Answer 7

• Arteries: Carry blood away from the heart
• Capillaries: Exchange of materials at the tissues
• Veins: Carry blood to the heart

Question 8

Arteries

Answer 8

• Heart pumps blood at high pressure
• Artery walls are strong and have elastic fibres
• Contain think layers of muscle before lumen
• Largest artery in the body: Aorta

Question 9

Capillaries

Answer 9

• Arteries branch into capillaries
• Really small
• Carry blood very close to every cell to exchange substances
• They have permeable walls
• Supply food and oxygen and take away waste like CO2
• Walls one cell thick

Question 10

Veins

Answer 10

• Capillaries join to form veins
• Blood is at lower pressure so walls not as thick
• Bigger lumen to help blood flow
• Also have valves to help blood flow in the right direction
• Largest vein in the body: Vena cava

Question 11

Blood flow through the heart

Answer 11

1. Right atrium receives deoxygenated blood from body (through vena cava)
2. Deoxygenated blood moves through the right ventricle which pumps it to the lungs (via pulmonary artery)
3. Left atrium receives oxygenated blood from lungs (through pulmonary vein)
4. Oxygenated blood then moves through to the left ventricle which pumps it out the heart (Aorta)

Question 12

Heart adaptations

Answer 12

• Left ventrice has much thicker wall as it needs more muscle as it pumps blood around the whole body.
• Valves prevent the backflow of blood.

Question 13

How does exercise affect heart rate:

Answer 13

Heart rate increases:
- Exercise increases the amount of CO2 in the blood
- High levels of blood CO2 are detected by receptor in the aorta and carotid artery.
- These receptors send signals to the brain
- Brain sends signals to the heart causing it to contract more frequently + with more force.

Question 14

Hormonal system on heart rate

Answer 14

• When organism threatened the adrenal glands release andrenaline
• Andrenaline binds specific receptors in the heart causing it to contract more frequently with more force.
• increases blood supply to all tissues making the body be ready for action

Question 15

What is coronary heart disease?

Answer 15

When coronary arteries that supply blood to the muscles are blocked by layers of fatty materials

Question 16

Risk factors for coronary heart disease:

Answer 16

1. Having a diet of high saturated fats. Leads to fatty deposits in the arteries.
2. Smoking as it increases blood pressure that can cause damage to the arteries
3. being inactive leads to high blood pressure which can damage the arteries and damage makes fatty deposits more likely to form

Question 17

Roles of the urinary system

Answer 17

1. Removal of the urea from blood. Excess amino acids
2. Adjustment of ion levels in blood
3. Adjustment of water content of the blood.