B4 organising animals and plants

Question 1

what are four parts of the blood

Answer 1

red blood cells
plasma
white blood cells
platelets

Question 2

plasma percentage of blood is

Answer 2

55%

Question 3

red blood cells percentage of blood is

Answer 3

45%

Question 4

white blood cells percentage of blood is

Answer 4

<1%

Question 5

platelets percentage of blood is

Answer 5

<1%

Question 6

what is the structure of plasma

Answer 6

• Straw yellow liquid

- Made up of water and dissolved substances.

Question 7

what are the functions of plasma

Answer 7

• Plasma transports many dissolved substances around the body. -Examples include digested foods (e.g. glucose), gases (e.g. carbon dioxide), wastes (e.g. urea) and hormones (e.g. insulin), antibodies, anti-toxins.
• Plasma also transports heat around the body.

Question 8

what are the structures of the red blood cells

Answer 8

• Very small in size. This provides a large surface area to volume ratio.
• They contain Haemoglobin - this is a red pigment that binds oxygen􏰌 oxyhaemoglobin)
• They are shaped like discs 􏰁(biconcave) but are thicker at the edges
• They have NO nucleus (so there is more space for haemoglobin)

Question 9

what are the functions of red blood cells

Answer 9

• To transport oxygen to all the body cells for respiration.

- Haemoglobin binds oxygen molecules forming oxyhaemoglobin.

Question 10

what are the structures of white blood cells

Answer 10

• Much bigger than red blood cells.
• Much fewer in number than red blood cells.
• They HAVE a nucleus.
• They have no definite shape

Question 11

what are the functions of white blood cells

Answer 11

-They help protect the body againstdisease.

Phagocytes 􏰁 eng􏰄lf 􏰎􏰊ea􏰅􏰋􏰏 pa􏰅hogens Lymphocytes 􏰁 create antibodies which destroy pathogens

Question 12

what are the structures of platelets

Answer 12

• These are tiny fragments of cells
• They have NO nucleus
• They cause blood to clot

Question 13

what are the functions of platelets

Answer 13

Their function is to help form blood clots. This helps seal wounds (and prevent blood loss) when we cut ourselves.

Question 14

What is meant by humans having a 􏰊double circulatory system􏰋

Answer 14

The heart is an organ that pumps blood around the body in a double circulatory system. The right ventricle pumps blood to the lungs where gas exchange takes place. The left ventricle pumps blood around the rest of the body.

Question 15

state three blood vessels

Answer 15

arteries
veins
capillaries

Question 16

what is the function of an artery

Answer 16

Function of artery: transport (usually) oxygenated blood under high pressure away from the heart (except the pulmonary artery which transports deoxygenated blood to the lungs).

Question 17

what is the function of a vein

Answer 17

Function of vein: transport (usually) deoxygenated blood to the heart (except the pulmonary vein which transport oxygenated blood into the left atrium).

Question 18

what is the function of a capillary

Answer 18

Function of capillary: allow fast exchange/diffusion of substances e.g. glucose, oxygen - out of the blood into the body cells/tissues.

Question 19

what is the pathway of blood flow through the heart

Answer 19

(RHS) Vena cava􏰌 to right atrium to 􏰌right ventricle􏰌 to pulmonary artery (pumps blood to the lungs) to 􏰌(LHS) Pulmonary vein􏰌 to left atrium􏰌 to left ventricle to 􏰌aorta (pumps blood all around the body).

Question 20

What are the coronary arteries

Answer 20

these are the arteries that supply the heart muscle with oxygen and glucose for respiration.

Question 21

How can blocked coronary arteries lead to heart disease?

Answer 21

In coronary heart disease layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.

Question 22

name 6 treatments for cardiovascular diseases

Answer 22

stent 
statins 
artificial valve 
transplant 
artificial pacemaker 
artificial heart

Question 23

what is a stent

Answer 23

a stent is a w􏰈ire mesh 􏰎􏰊balloon􏰋􏰏 􏰈which is inser􏰅ted in􏰅to a (blocked) coronary artery to widen the artery and allow more blood to flow.

Question 24

what are a stents advantages

Answer 24

• Minor operation􏰎 (doesn’t􏰋􏰅 need general anaesthetic)

- lower risk of heart attack.

Question 25

what are a stents disadvantages

Answer 25

-Risk of infection from the surgery.

Question 26

what is a statin

Answer 26

statins are drugs taken to reduce blood cholesterol levels, which slows down the rate of fatty deposit build up in the coronary arteries.

Question 27

what are a statins advantages

Answer 27

• Does not require surgery
• Reduces the risk of arteries narrowing.
• reduces the risk of strokes and coronary heart disease.

Question 28

what are a statins disadvantages

Answer 28

• May increase risk of developing type 2 diabetes

- Need to be taken long term daily. People might forget.

Question 29

what is an artificial valve

Answer 29

• Valves in the heart prevent backflow of blood. -If the valve becomes faulty this could prevent the valve from opening fully, or the heart valve might develop a leak.
• Faulty heart valves can be replaced using biological or mechanical valves.

Question 30

what are an artificial valves advantages

Answer 30

High success rate

Question 31

what are an artificial valves disadvantages

Answer 31

• Risk of infection
• Need to take blood thinners as blood clots may form.
• Major surgery is involved.

Question 32

what is a heart transplant

Answer 32

Replacement of a faulty / diseased heart with that of one donated by another person.

Question 33

what are heart transplants advantages

Answer 33

Can treat several heart conditions Increase life expectancy

Question 34

what are heart transplants disadvantages

Answer 34

Risk of rejection

3 year waiting list for compatible donor

Question 35

what is an artificial pacemaker

Answer 35

The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker. Artificial pacemakers are electrical devices used to correct irregularities in the heart rate.

Question 36

what is an artificial pacemakers advantages

Answer 36

Long lasting devices

Question 37

what is an artificial pacemakers disadvantages

Answer 37

Doesn’t 􏰋􏰅treat􏰅 heart􏰅 disease

Patient needs to avoid magnetic and electromagnetic fields of energy.

Question 38

what is an artificial heart

Answer 38

If donor organs are not available doctors may insert an artificial heart.-

• It is a mechanical device that can pump blood for a person who has a failed heart.
• They are used as a temporary fix to keep someone alive until they can have a heart transplant.

Question 39

what are an artificial hearts advantages

Answer 39

-Less likely to be rejected than a donor heart.

Question 40

what are an artificial hearts disadvantages

Answer 40

• Major surgery is involved which carries high risk of bleeding and infection.
• Artificial hearts could malfunction.

Question 41

What are the adaptations of the alveoli in the lungs for efficient gas exchange? You must always mention the structure and function in your answer.

Answer 41

􏰀 Structure: alveoli have a very large surface area
􏰀 Function: this provides maximum diffusion of gases
􏰀 Structure: each alveolus is surrounded by a network of capillaries near the surface
􏰀 Function: to maintain a steep concentration gradient, this means a faster rate of diffusion.
􏰀 Structure: the alveoli have thin moist walls
􏰀 Function: this provides a short (& quicker) diffusion pathway for gases

Question 42

How does light intensity affect the rate of transpiration?

Answer 42

The brighter the light, the greater the transpiration rate. Stomata begin to close as it gets darker. Photosynthesis can’t happen in the dark, so hey don’t need to be open to let in CO2 in. When the stomata are closed, very little water can escape.

Question 43

How does temperature affect the rate of transpiration?

Answer 43

The warmer it is, the faster transpiration happens. When it’s warm the water particles have more energy to evaporate and diffuse out of the stomata.

Question 44

How does air flow affect rate of transpiration

Answer 44

the better the air flow around a leaf (e.g. stronger wind), the greater the transpiration rate. If air flow around a leaf is poor, the water vapour just surrounds the leaf and doesn’t move away. This means there’s a high concentration of water particles outside of the leaf as well as inside it, so diffusion doesn’t happen as quickly. If there’s good air flow, the water vapour is swept away, maintaining a low concentration of water in the air outside the leaf. Diffusion then happens quickly, from an area of higher concentration to an area of lower concentration.

Question 45

How does the humidity affect the rate of transpiration?

Answer 45

the drier the air around the leaf, the faster transpiration happens. This is like what happens with air flow. If the air is humid. There’s a lot of water in it already, so there’s not much of a difference between the inside and the outside of the leaf. Diffusion happens fastest if there’s a really high concentration in one place, and a really low concentration in the other.