Exchange Of Substances

Question 1

What is diffusion

Answer 1

The random movement of molecules from a region of high concentration to a low concentration until dynamic equilibrium is reached
Passive process

Question 2

What is osmosis

Answer 2

The random movement of water across a partially permeable membrane from a less concentrated solution to a more concentrated solution

High to low water potential

Question 3

What is facilitated diffusion

Answer 3

High to low concentration
Passive process (requires no ATP)
Through a carrier protein

Question 4

What is co transport

Answer 4

1. Sodium ions are actively transported out of the epithelial cells into the blood via the sodium-potassium pump
2. Sodium ions diffuse into the cell from lumen using sodium-glucose co-transported proteins
3. Glucose is therefore also transported into the cell
4. Glucose passes into the blood plasma via facilitated diffusion

Question 5

What happens during inhalation

Answer 5

Internal intercostal muscles relax 
External intercostal muscles contract 
Ribs move up and out 
An increase in volume 
The diaphragm flattens and contracts 
Pressure lowers

Question 6

What happens during expiration

Answer 6

Internal intercostal muscles contract 
External intercostal muscles relax 
Ribs move down and in 
Decease in volume 
The diaphragm relaxes and becomes domed
Pressure higher

Question 7

Features of a lung

Answer 7

Trachea 
Bronchus 
Ribs
External intercostal muscles 
Internal intercostal muscles 
Diaphragm 
Bronchioles 
Alveoli 
Lungs

Question 8

Role of alveoli

Answer 8

LSA:volume
Very thin- short diffusion pathway
Partially permeable- allows selected material to pass
Movement of internal/external medium- maintains diffusion gradient

Question 9

Pulmonary fibrosis

Answer 9

Scars form on epithelium cells- thickened
Longer diffusion pathway
Elasticity reduced

Shortness of breath 
Dry cough 
Pain in chest 
Weakness 
Fatigue

Question 10

Asthma

Answer 10

Allergens (eg. Dust, fur, pollen) 
Lining of airways inflamed
Cells secrete mucus 
Fluid enters airways 
Muscles surrounding bronchus contract 

Difficulty in breathing
Wheezing
Coughing

Question 11

Emphysema

Answer 11

Due to smoking
Elastin permanently stretched=scarring
Alveoli has a smaller surface area and bursts

Shortness of breath
Coughing
Bluish skin

Question 12

Tuberculosis

Answer 12

Caused by mycobacterium tuberculosis
Grows in upper regions of the lungs
White blood cells at the side of infection= inflammation and increases size of lymph nodes

Coughing (up blood)
Fever
Fatigue
Loss of appetite

Question 13

How do you find out pulmonary ventilation?

Answer 13

Pulmonary ventilation= tidal volume (dm^3) x ventilation rate (min^-1)

Question 14

How does oxygen move from an alveolus to the blood

Answer 14

Via diffusion (lower con in blood stream and higher in alveolus) 
High diffusion gradient as blood is constantly moving 
Through epithelium which is thin(1 cell thick) means a short diffusion pathway

Question 15

How to increase the rate of diffusion

Answer 15

Increase the con. Gradient
Increase the size of exchange surface
Decrease thickness of Exchange surface
Increase the movement of internal/external medium