Organisation

Question 1

What are the 3 types of blood vessles?

Answer 1

• veins
• capillaries
• arteries

Question 2

What is an artery’s function?
How is it adapted to it’s function?

Answer 2

Function: It transports oxygenated blood FROM the heart TO the organs (with the exception of the pulmonary artery)
Adaptation: It has thick layers of muscle - suited to the high pressure at which blood is pumped from the heart. It has elastic fibres which allow them to stretch and recoil.

Question 3

What is a capillary’s function?
How is it adapted to it’s function?

Answer 3

Function: It exchanges food and oxygen from the blood to the cells. It exchanges waste product from the cells to the blood.
Adaptation: It has thin walls and passes very close to bodily cells for a shorter diffusion distance

Question 4

What is a vein’s function?
How is it adapted to it’s function?

Answer 4

Function: It carries deoxygenated blood from the capillaries to the heart. (with the exeption of the pulmonary vein)
Adaptation: It has thinner walls, as the blood is coming in at a lower pressure. It has a wider lumen also due to the lower pressure. And it has valves to stop the blood from backflowing.

Question 5

What are the 4 chambers of the heart?

Answer 5

• left atrium
• right atrium
• left ventricle
• right ventricle

Question 6

How does blood flow through the body?

(6 marks)

Answer 6

• deoxygenated blood goes through the vena cava and enters the right atrium
• the right atrium contracts so the blood goes through the valves (that prevent backflow) and it enters the right ventricle
• the right ventricle contracts and forces the blood out of the heart through the pulmonary artery and into the lungs
• oxgenated blood enters the left atrium through the pulmonary vein
• the left atrium contracts and blood travels through the one-way valves into the left ventricle
• the left ventricle contracts and forces oxgenated blood out of the heart, through the aorta to the rest of the body.
• the muscle around the left chambres of the heart is thicker than the right. this is because a greater force exerted by these larger muscles is needed to pump blood to the whole body, instead of just to the lungs.

(6 marks)

Question 7

What is the pathway of oxygen into the body?

Answer 7

• Oxygen is inhaled, sent to the lungs through the trachea
• the trachea divides into 2 bronchi, one on either side for the lungs
• the bronchus divides into many bronchioles of which ends in alveoli (tiny air sacs.)
• deoxygenated blood is sent to the lungs via the pulmonary artery. here it picks up oxygen that binds to it’s haemoglobin.
• the now oxygenated blood leaves the lungs, and enters the left side of the heart, where it is pumped to the rest of the body.

Question 8

How are alveoli adapted to their function?

Answer 8

• surrounded by capilaries so it has a) a rich blood supply and b) a shorter diffusion distance
• it also has a larger surface area to increase the rate of diffusion/allows gas exchange in the lungs
• it has thin walls which makes the diffusion of gas faster

Question 9

What happens in the alveolus (air sac)?

Answer 9

In the alveolus, oxygen and carbon dioxide are exchanged between the blood in the capillaries and the air in the lungs. They come into the alveolus deoxygenated, and leave oxygenated.

Question 10

Where are digestive enzymes produced?

Answer 10

• specialised cells in the glands
• the lining of the gut.

Question 11

Name the functions of the following parts of the digestive system:

Stomach
Liver
Small Intestine
Large Intestine

Answer 11

Stomach - produced hydrochloric acid which helps break down food
Liver - produces bile which aids enzymes in breaking down food
Small intestine - continues digestion and absorbs soluble food mollecules
Large intestine - absorbs water mollecules from undigested food, which then produces faeces.

Question 12

What are tissues?

Answer 12

Groups of similar cells that act together to perform a similar function

Question 13

What are organs?

Answer 13

Groups of distinct tissues that work together to perform a specific function

Question 14

What does it mean when an enzyme is “denatured”

Answer 14

if its structure is altered and it can no longer catalyse a reaction.

Question 15

What is bile?

Answer 15

An alkaline substance produced in the liver and stored in the gallbladder.
- it neutralises acid from the stomach as enzymes in the small intestine work optimally at a more alkaline pH
- it emulsifies fat droplets, which increace their surface area, and therefore the rate of lipase-catalysed reactions in breaking them down.

Question 16

Name the 3 digestive enzymes, what they break down, where they are released, and what they produce.

Answer 16

Carbohydrase (Amylase): Breaks down starch into simple sugars (e.g, maltose sugars). Produced in the pancreas and salivary glands. Active in the mouth and small intestine.
Protease: breaks down proteins into amino acids. Produced in the pancreas and the stomach. and small intestine
Lipase: breaks down lipids (fats) into glycerol and fatty acids. produced in the small intestine and pancreas.

Question 17

What are the tests for carbs, lipids and protien? And how do they work?

Answer 17

Carbohydrates (Starch): Iodine solution. Originally orangey-brown Will turn blue/black in the presence of starch.
Carbohydrates (Sugars): Benedict’s reagent poured into the solution and heated. Originally aqua blue. Will turn green, yellow or brown in the presence of sugar, depends on it’s concentration.
Lipids (fats): Ethanol and water are added to the solution and shaken. Will turn cloudy in the presence of lipids.
Protiens: Add Biuret solution. Originally blue. Will turn mauve or purple in the presence of protiens.

Question 18

What are the 3 parts of blood plasma and what are their functions?

Answer 18

• platelets (have no nucleus and trigger blood clotting at wound sites)
• red blood cells (allows the body to carry out respiration for energy through binding to haemoglobin)
• white blood cells (which are part of the immune response. some (phagocytes) engulf pathogens

(all of the above are suspended in blood plasma)

Question 19

What are the two different types of tumors and what are their differences?

Answer 19

Malignant - A cancerous tumor that spreads to other areas of the body, leading to secondary tumors
Benign - A non-cancerous tumor that stays within one part of the body, often within a mebrane.

Question 20

What are the 4 primary risk factors for different cancers?

Answer 20

• obesity
• exposure to UV rays
• smoking
• genetics

Question 21

What is cancer?

Answer 21

A non-communicable group of diseases that
- develop in the body due to uncontrollable rapid cell division
- which leads to tumours, and the subesequent spread of them around the body

Question 22

What is a drug?

Answer 22

A substance that affects the chemical reactions in a person’s body.

Question 23

How does oxygen enter a cell through the bloodstream?

(3 marks)

Answer 23

• diffusion
• down the concentration gradient (high to low)
• through the cell membrane

(3 marks)

Question 24

Where in the heart are pacemaker cells found?

Answer 24

Right Atrium

Question 25

Why is the human circulatory system called a double circulatory system?

Answer 25

• it has to go to the lungs to pick up oxygenated blood
• then to the body to transport the oxygenated blood.

Question 26

What is a tissue?

Answer 26

A collection of cells with a similar structure that work together to perform a similar function.

Question 27

What is the function of plasma?

Answer 27

It carries substances like CO2, glucose, urea and hormones for transport across the body