B4

Question 1

What is the Circulatory system and why is it needed?

Answer 1

The heart, blood and vessels. Large organisms need it because the small SA:V.

Question 2

What does blood do?

Answer 2

Protects the body from pathogens.
Carries oxygen to the bodies cells.
Carries carbon dioxide away from the bodies cells.
Carries nutrients to the cells for function and growth (glucose and minerals).
Carries the waste product urea to be excreted by the kidneys.

Question 3

What is an Artery and what do they do?

Answer 3

They are a blood vessel that carry blood away from your heart to the organs. This blood is oxygenated. They have thick walls containing muscle and elastic fibres because there is a high blood pressure from the heart. They stretch as the blood is forced through them and then quickly recoil back after. They also have a small lumen.

Question 4

What is a Vein and what do they do?

Answer 4

They are a blood vessel and carry blood away from the organs towards the heart. This blood is deoxygenated. They have thin walls because there is low pressure and have valves to stop the back flow of blood. The blood is squeezed by skeletal muscles. They have a large lumen.

Question 5

What is a Capillary and what do they do?

Answer 5

They are a blood vessel that form a huge network of tiny vessels that link the arteries and the veins. They are very small and narrow with one-cell-thick walls which allow substances to easily diffuse through.

Question 6

What is the lumen?

Answer 6

The hole down the middle of a blood vessel; where the blood flows through.

Question 7

What are Platelets and what do they do?

Answer 7

Cell fragments that start the clotting process at wound sites. They are attracted by the tough fibres surrounding the vessel wall.

Question 8

What are Red blood cells and what do they do?

Answer 8

Contain haemoglobin that binds to oxygen to transport from the lungs to the tissues. They have no nucleus and are concave to increase surface area and the amount of haemoglobin they carry.

Question 9

What are White blood cells and what do they do?

Answer 9

Help to protect the body from infection and are attracted by bacteria. They can change shape allowing them to wrap round ‘alien’ microbes in the body.

Question 10

What is Plasma and what does it do?

Answer 10

A liquid that has all the blood cells suspended in it and transports proteins and other chemicals around the body.

Question 11

Name the four chambers of the heart.

Answer 11

Left atrium
Right atrium (Atria for plural)
Left ventricle
Right ventricle

Question 12

What is the function of the right atrium?

Answer 12

Blood enters from the vena cava and is deoxygenated and sent to the right ventricle. Thin walls.

Question 13

What is the function of the right ventricle?

Answer 13

Pumps blood to the lungs via the pulmonary artery where gas exchange takes place. Thick walls.

Question 14

What is the function of the left atrium?

Answer 14

Pushes blood from the lungs to the left ventricle. Thin walls.

Question 15

What is the function of the left ventricle?

Answer 15

Pumps blood to and around the rest of the body. Very thick walls.

Question 16

What does the Aorta do?

Answer 16

Sends blood to the body from the heart.

Question 17

What does the Vena Cava do?

Answer 17

Sends blood to the heart from the body.

Question 18

What does the Pulmonary Artery do?

Answer 18

Sends blood to the lungs from the heart.

Question 19

What does the Pulmonary Vein do?

Answer 19

Sends blood to the heart from the lungs.

Question 20

What do the Coronary Arteries do?

Answer 20

Supply the heart with oxygenated blood.

Question 21

What are stents and what are they used for?

Answer 21

Metal grinds that can be inserted into a coronary artery to keep it open if it gets blocked up by layers of fatty material building up. This makes sure the blood can keep passing through, also reducing the risk of coronary heart disease (so a heart attack) and to keep the heart beating.

Question 22

What is statin and what is it used for?

Answer 22

A drug/medicine used to reduce cholesterol in the blood which clears out the fat build up inside the arteries. This reduces the risk of cardiovascular disease and the risk of mortality of those who were at a high risk and prevents heart disease.

Question 23

Name the four heart valves.

Answer 23

Tricuspid valve
Mitral valve
Aortic valve
Pulmonary valve

Question 24

What do the mitral and tricuspid valves do?

Answer 24

Control the blood flow from the atria to the ventricles.

Question 25

What do the aortic and pulmonary valves do?

Answer 25

Control blood flow out of the ventricles and into the blood vessels.

Question 26

What do valves do?

Answer 26

Let blood pass smoothly in one direction and can close quickly to prevent any back flow of blood.

Question 27

What are damaged heart valves and what happens to them?

Answer 27

They are leaking or stiff valves that don't open properly. Damaged valves are replaced with biological or mechanical valves. Mechanical valves are made of things like titanium and polymers and last a very long time but need medicine to sustain whereas biological valves don't last very long (12-15 years) but don't need medicine.

Question 28

What are artificial pacemakers and what do they do?

Answer 28

Electrical devices used to correct irregularities in the heart rhythm. They are needed when the group of cells in the right atrium stop working. They are attached to the heart with two wires that send electrical signals to the heart to make it beat properly. Needs regular medical checkups.

Question 29

What are artificial hearts and what do they do?

Answer 29

They are fake hearts that are used to keep patients alive while they wait for a transplant or to give diseased hearts a rest. They need lots of machinery to keep them working so the patient must stay in hospital.

Question 30

How do lungs work?

Answer 30

1. Diaphragm contracts and moves down (flattens). 2. External intercostal muscles contract which lifts the ribs up and out. 3. Increase in volume causes decrease in pressure inside lungs so air rushes in. 4. Diaphragm relaxes and moves upwards. 5. Intercostal muscles relax causing ribs to fall down and inwards. 6. Decrease in volume of thorax so air is pushed out.

Question 31

What are the main structures of the gas exchange system?

Answer 31

``` Trachea* Bronchioles Alveoli* Bronchi* Lungs Capillary network* ```

Question 32

What is the trachea and what does it do?

Answer 32

Long flexible tube that allows air to pass through and into the bronchi. It is flexible so the animal can move around without restrictions and is kept open by cartilage rings.

Question 33

What are the bronchi and what do they do?

Answer 33

Extensions of the wind pipe (trachea) that lead into the lungs and allow air to pass back and forth. Kept open by cartilage rings.

Question 34

What are the alveoli and what do they do?

Answer 34

Small bags found in clusters and have a very big surface area. They have a very rich supply of blood capillaries that keep a concentration gradient in both directions. They are only one cell thick and the blood capillaries are very close to the alveoli for faster diffusion.

Question 35

What is the capillary network and what does it do?

Answer 35

Surround every alveoli and keep bringing deoxygenated blood to keep a high concentration gradient to keep diffusion fast and efficient. They are very close to the alveoli.

Question 36

Name six adaptions for more efficient diffusion.

Answer 36

``` Increase SA Decrease diffusion distance Thinner walls Better blood supply More moist Increase conc. gradient ```

Question 37

What is the epidermal tissue and what does it do?

Answer 37

Work as the plant skin (transparent) and protect the internal tissue from the outside by creating a barrier. It is a layer of cells all joined together.

Question 38

What is the palisade mesophyll and what does it do?

Answer 38

Densely packed cells that are very close together and very tall to absorb the maximum light possible.

Question 39

What is the spongy mesophyll and what does it do?

Answer 39

Allows the interchange of gases that are needed for photosynthesis. They have air spaces between them for easy gas exchange.

Question 40

What is the xylem and what does it do?

Answer 40

Causes upwards water transport through plants. Also replaces water lost during transpiration and photosynthesis. Tube like structure with liguin spirals in them.

Question 41

What is the phloem and what does it do?

Answer 41

Transports food from leaves to the rest of the plant. Have sieve plates and companion cells with them.

Question 42

What is the meristem tissue and what does it do?

Answer 42

Found at the growing tips of shoots and roots. Produce new cells through mitotic division. Helps plant increase the lateral growth of its stems, branches and roots.

Question 43

What is transpiration?

Answer 43

The evaporation of water from the aerial parts of plants like open stomata or the lower epidermis of leaves. 90% of water taking in is lost in transpiration.

Question 44

How does light intensity affect transpiration?

Answer 44

Causes more photosynthesis in the plant so the stomata are more open causing more water to transpire out. Increase T.R.

Question 45

How do air currents affect transpiration?

Answer 45

Causes the water that has transpired to move away quickly so there is always a high concentration gradient because it is replaced with dry air. Increase T.R.

Question 46

How does temperature affect transpiration?

Answer 46

Causes the stomata to open or close depending on whether it is cold (close) or warm (open). This can either increase T.R. (Warm) or decrease it (cold).

Question 47

How does humidity affect transpiration?

Answer 47

Causes the concentration gradient change to make it become more balanced or less balanced so transpiration is slowed down (more humid) or speed up (less humid).