Transport in humans

Question 1

Diffusion

Answer 1

Net movement of particles from an area of high concentration to an area of low concentration

Question 2

Describe the movement of molecules

Answer 2

Constant and random

Question 3

What is diffusion responsible for?

Answer 3

The movement of substances in living things

Question 4

Give two examples of diffusion

Answer 4

Small molecules pass through cell membranes to cytoplasm

Diffusion moves oxygen and glucose into cells for respiration and removes carbon dioxide and other wastes

Question 5

What are four factors affecting the rate of diffusion?

Answer 5

Surface area
Temperature
Volume
Concentration gradient

Question 6

As cells and organisms get bigger, what increases more?

Answer 6

Volume

Question 7

What affect does SA:V ratio have on diffusion?

Answer 7

Increased volume = decreased surface area = slower rate of diffusion

Question 8

Name two specialised exchange surfaces to maximise diffusion in humans

Answer 8

Alveoli in the lungs

Villi in the small intestine

Question 9

What is the function of the circulatory system?

Answer 9

To transport substances around the body e.g oxygen and nutrients to cells and waste products from cells to lungs and kidneys

Question 10

What three things does the circulatory system require to do its job?

Answer 10

Liquid to transport substances in - the blood
A pump - the heart
A series of pipes to move the blood efficiently - the blood vessels

Question 11

What is double circulation?

Answer 11

The heart pumps the blood twice sending it through two different circulatory circuits

Question 12

What is the pulmonary circulation?

Answer 12

Deoxygenated blood is pumped to the lungs where oxygen is gained and carbon dioxide is lost. It is then pumped back to the heart

Question 13

What is the systemic circulation?

Answer 13

Oxygenated blood pumped round the body where the cells absorb oxygen and release carbon dioxide.

Question 14

What artery goes to the liver?

Answer 14

Hepatic artery

Question 15

What vein leaves the liver?

Answer 15

Hepatic vein

Question 16

What artery goes to the kidneys?

Answer 16

Renal artery

Question 17

What vein leaves the kidneys?

Answer 17

Renal vein

Question 18

What is the vena cava?

Answer 18

Main vein carrying deoxygenated blood back to the heart.

Question 19

What is the aorta?

Answer 19

Main artery carrying oxygenated blood away from the heart

Question 20

Why is a double circulatory system more efficient than a single?

Answer 20

By pumping blood twice, higher pressures can be maintained and so blood can move further and faster

Question 21

What is metabolic rate?

Answer 21

The rate of chemical reactions in the body

Question 22

What is blood?

Answer 22

A complex tissue consisting of a liquid component (plasma), cell fragments (platelets) and two types of cells (red and white blood cells)

Question 23

What is plasma?

Answer 23

A straw coloured liquid, mainly water, which transports the blood cells and carries dissolved nutrients (glucose and amino acids), dissolved waste products (urea and carbon dioxide), hormones (protein and fats). It also distributes heat energy around the body

Question 24

What are platelets?

Answer 24

Small cell fragments which help to form clots preventing blood loss and infection

Question 25

What is the function of white blood cells?

Answer 25

To destroy pathogens which infect our body. They are an essential part of the immune system

Question 26

Function of red blood cells

Answer 26

To transport oxygen

Question 27

About red blood cells

Answer 27

Highly specialised cells Made in the bone marrow Only live for around 100 days Contain haemoglobin

Question 28

What shape are red blood cells?

Answer 28

Biconcave. Increases surface area: volume ratio and decreases distance to centre of cell, allowing for efficient diffusion of oxygen in and out. No nucleus means more haemoglobin can be packed in so more oxygen can be transported

Question 29

What is haemoglobin?

Answer 29

An iron-containing protein

Question 30

How does haemoglobin work?

Answer 30

When oxygen concentration is high (in lungs) It combines with oxygen to form oxyhaemoglobin When oxygen concentration decreases (in respiring tissues) oxyhaemoglobin releases the oxygen.

Question 31

What is the function of the heart?

Answer 31

To pump blood around the body

Question 32

Where is the heart?

Answer 32

In the centre of the thorax partially surrounded by the lungs and protected by the rib cage

Question 33

What is the heart made of?

Answer 33

Cardiac muscle

Question 34

What is the average resting heart rate?

Answer 34

70

Question 35

What does the right side of the heart do?

Answer 35

Pumps deoxygenated blood to the lungs

Question 36

What does the left side of the heart do?

Answer 36

Pump oxygenated blood to the rest of the body

Question 37

Structure of the heart?

Answer 37

Four chambers (two atria at the top, two ventricles at the bottom)

Question 38

Describe atrium walls

Answer 38

Thin muscular

Question 39

Describe ventricle walls

Answer 39

``` Thick muscular (septum) Left ventricle wall much thicker than right due to higher blood pressure ```

Question 40

Name the two circulatory systems

Answer 40

Pulmonary (lungs) and systemic (rest of body)

Question 41

What is the vena cava?

Answer 41

Blood vessel bringing deoxygenated blood into the heart

Question 42

What are the pulmonary veins?

Answer 42

Vessels carrying oxygenated blood from lungs to heart

Question 43

What do veins carry?

Answer 43

Deoxygenated blood except pulmonary vein

Question 44

What do arteries carry?

Answer 44

Oxygenated blood except pulmonary artery

Question 45

Name the valves in the heart

Answer 45

Semilunar, bicuspid and tricuspid

Question 46

What do tricuspid and bicuspid valves do?

Answer 46

Stop blood from flowing back into the atria

Question 47

What do semilunar valves do?

Answer 47

Prevent flow of blood back into the heart

Question 48

What causes heart valves to open and close?

Answer 48

Changes in blood pressure

Question 49

Structure of an artery

Answer 49

Thick outer wall Thick layer of muscles and elastic fibres Small lumen to allow expansion under pressure

Question 50

What helps blood flow in arteries?

Answer 50

A thin layer of endothelial cells

Question 51

Structure of veins

Answer 51

Fairly thin outer wall Thin layer of muscle and elastic fibres Large lumen, enables blood to flow easily Contain one way pocket valves to prevent back flow of blood

Question 52

What are capillaries?

Answer 52

Very thin blood vessels with single layer cell wall for easy diffusion

Question 53

What is heart rate?

Answer 53

Number of beats per minute

Question 54

What is stroke volume?

Answer 54

Volume of blood pumped with each heartbeat

Question 55

Why does heart rate increase with exercise?

Answer 55

To increase supply of oxygen To provide extra glucose To remove excess heat energy To remove carbon dioxide

Question 56

What is fight or flight?

Answer 56

Increase in oxygen and glucose to the muscles when angry or afraid triggered by adrenaline

Question 57

What is the medulla?

Answer 57

Part of the brain that controls heart rate