11. Gas Exchange

Question 1

Describe the features of gas exchange surfaces

Answer 1

Large surface area to allow faster diffusion of gases across the surface
Thin walls to ensure diffusion distances remain short
Good ventilation with air so that diffusion gradients can be maintained
Good blood supply to maintain a high concentration gradient so diffusion occurs faster

Question 2

Draw a diagram with lung, diaphragm, ribs, intercostal muscles, larynx, trachea, bronchi, bronchioles, alveoli, and associated capillaries

Answer 2

Refer to Book

Question 3

Describe trachea

Answer 3

Tracker has rings of cartilage
Cartilage prevents trachea from collapsing when inside air pressure is lower than outside air pressure

Question 4

Composition of inspired and expired

Answer 4

I. E
Oxygen. 21. 16
Co2. 0.04. 4
Water. Variable. V.hugh

Question 5

Describe inspiration

Answer 5

Muscles of diagram contract(pulled down)
So volume of thorax increases
External intercoastal muscles contract
So rib cage is pulled upward and outward
Internal intercostal muscle relax
Air pressure inside falls
Air flows in

Question 6

describe expiration

Answer 6

Diaphragm muscle relax (domed)
So volume of thorax is decreased
External intercostal muscle relax
Rib cage drops down
Abdomen and internal intercostal muscle contract

Question 7

Explain the link between physical activity and the rate of depth of. Breathing.

Answer 7

During exercise muscle contracts harder and more frequently requiring more energy
Extra energy is provided by anaerobic respiration
Breakdown of glucose forms lactic acid and energy
A lot of lactic acid is produced in the muscle cells
And it must be broken down by combining it with oxygen in the liver
This is done by aerobic respiration in the liver cell
You are taking in and transporting extra oxygen to breakdown the lactic acid
So you go into an oxygen debt

Or

Increased carbon dioxide concentration in the blood which is detected by the brain leading to an increased rate and greater depth of breathing