Exchange surfaces & Breathing

Question 1

What is the function of Goblet cells?

Answer 1

Secrete mucus that traps microorganisms inhaled in the air

Question 2

What is the function of the Cilia?

Answer 2

Moves the mucus and trapped microorganisms away from alveoli, helping prevent lung infections

Question 3

What is the function of Elastic fibres in the gaseous exchange system?

Answer 3

Help process of breathing out, (lungs inflate and fibres are stretched, and recoil to push out air when exhaling)

Question 4

What is the function of Smooth muscle?

Answer 4

Control diameter of Trachea, Bronchi, Bronchioles. In exercise, it relaxes, widening tube so air can get in/out easier

Question 5

What is the function of the rings of cartilage?

Answer 5

In walls of trachea and bronchi and provide support, sp trachea doesn’t collapse when you breathe in and the pressure drops

Question 6

Describe the cartilage present in the trachea

Answer 6

Large C-shaped pieces

Question 7

What happens in Inspiration?

Answer 7

AIR FLOWS IN
- Volume of thorax increases, decreasing pressure
- Internal intercostal muscles contract causing ribs to
move upwards and outwards
- Diaphragm muscles contract, causing diaphragm to
move downwards and flatten

Question 8

What happens in Expiration?

Answer 8

AIR IS FORCED OUT
- Thorax volume reduces, air pressure increases
- External intercostal muscles relax, causing ribs to move
inwards and downwards
- Diaphragm muscles relax, causing diaphragm to become curved again

Question 9

What is ‘Tidal volume’?

Answer 9

The volume of air in each breath

Question 10

What is ‘Vital capacity’?

Answer 10

The maximum volume of air that can be breathed in/out

Question 11

What is ‘Breathing rate’?

Answer 11

How many breaths are taken, usually in a minute

Question 12

What is ‘Oxygen consumption/uptake’?

Answer 12

The rate at which an organism uses up oxygen

Question 13

What machine can be used to investigate breathing?

Answer 13

A Spirometer

Question 14

Why are root hair cells a good example of an exchange surface with a large surface area?

Answer 14

Each root has millions of these hair cells that give the root a large surface area to increase rate of absorption of water

Question 15

Why are the Alveoli a good example of a thin exchange surface?

Answer 15

Each one is made of a single layer of thin flat cells (Alveolar Epithelium)
Thin cells help decrease the diffusion distance for the 02 and CO2, increasing the rate of diffusion

Question 16

Why are the Alveoli a good example of an exchange surface with a good blood supply?

Answer 16

Alveoli are surrounded by a large network of capillaries to give each one its own blood supply, taking oxygen away and bringing more CO2, helping maintain conc. gradient

Question 17

Which types of organisms need specialised exchange systems?

Answer 17

Large multicellular organisms

Question 18

Why do multicellular organisms need Transport Systems?

Answer 18

• Low SA:V ratio, higher metabolic rate
• Active = Large number of cells respiring v. quickly
• Diffusion won’t meet needs of cells constantly requiring
  oxygen

Question 19

How does the circulatory system work in fish?

Answer 19

Heart pumps deoxygenated blood to gills to pick up oxygen, then on through the rest of the body, and back do the heart, deoxygenated

Question 20

Describe an open circulatory system?

Answer 20

• Heart is segmented, it contracts in a wave, pumping
  blood into a single main artery
• Artery opens up into the body cavity
• Blood flows around insects organs, making way back to
  heart segments through series of valve

Question 21

Describe the structure of a Capillary

Answer 21

A layer of Endothelium one cell thick

Question 22

Describe the structure of a Vein

Answer 22

• Large lumen
• THIN muscle wall
• Endothelium

Question 23

Describe the structure of an Artery

Answer 23

• Folded Endothelium
• THICK muscle layer
• Elastic tissue in wall

Question 24

How is tissue fluid formed?

Answer 24

• At start of capillary bed, nearest arteries, hydrostatic pressure inside capillaries is greater than in the tissue fluid
• This difference forces fluid out of capillaries into spaces around the cells = forming tissue fluid

Question 25

Where does excess tissue fluid drain?

Answer 25

Into the Lymph system

Question 26

Why are Red blood cells only in the blood?

Answer 26

They’re too big to get through capillary walls into tissue fluid

Question 27

Why are no/very few white blood cells in the tissue fluid?

Answer 27

Because the only enter tissue fluid when there’s an infection