CF gas exchange

Question 1

where is mucus produced in the lungs

Answer 1

goblet cells found in the wall of the airway

Question 2

where is mucus found

Answer 2

thin layer coats tubes of gas exchange system

Question 3

what is the roll of mucus

Answer 3

to trap dust, debris and microorganisms
protect body

Question 4

where is cilia found

Answer 4

in epithelial cell lining the airways of gas exchange system (trachea and bronchi)

Question 5

how is mucus removed from the body

Answer 5

cilia remove it by wave like beating
mucus either coughed up or swallowed
when swallowed the stomach acid destroys the pathogens

Question 6

features of the lung lung which allows for rapid gas exchange

Answer 6

many alveoli
alveoli walls are one cell thick
capillary walls are one cell thick
ventilation of alveoli
blood flow in capillaries

Question 7

how gas exchange in the lungs works

Answer 7

air drawn into lungs via trachea
air moves to an area of low pressure in the lungs
trachea divides into to two bronchi which carry air to each lung
bronchus divides into bronchioles (narrower airways) ending in tiny alveoli
alveoli are the site of gas exchange

Question 8

features of the alveoli and why this makes them good for diffusion

Answer 8

features:
spherical
have a large surface area: volume ratio
benefits:
gives them a large surface area for:
diffusion of oxygen out of alveolus to capillaries
diffusion of carbon dioxide into alveolus from capillaries

Question 9

gas exchange in mammalian alveolus (movement of CO2 and O2)

Answer 9

oxygen moves from alveoli to blood by diffusion
carbon dioxide moves from blood to alveoli by diffusion
both movements are down a concentration gradient (high to low)
gases pass through epithelium of alveoli walls
gases pass through endothelium of capillary walls

Question 10

what effect does CF have on mucus produced

Answer 10

mucus contains less water than usual
makes it stickier which makes it harder for cilia to remove

Question 11

how does CF increase the chances of lung infection

Answer 11

mucus layer is stickier so cilia cannot remove it
mucus production continues and thickened layer builds up in the airway
02 levels drop in mucus (oxygen only diffuses slowly through it and epithelial cells use up more 02 in CF patients)
harmful bacteria thrive in anaerobic conditions

Question 12

how do white blood cells make the mucus even stickier

Answer 12

WBC fight the infection in the mucus
when they die and break down they release DNA which makes mucus stickier

Question 13

the effects of blockages in the lungs due to CF

Answer 13

sticky mucus blocks bronchioles
prevents ventilation of alveoli below blockage
reduces number of alveoli providing surface area for gas exchange
can cause inflation of alveoli and damage lung elasticity

Question 14

what factors affect the rate of diffusion

Answer 14

surface area
thickness of surface
concentration gradient

Question 15

what is the equation for ficks law

Answer 15

rate of diffusion is proportional to the surface area x difference in concentration /thickness of the membrane

Question 16

why is the rate of diffusion directly proportional to the membrane surface area

Answer 16

a larger surface area increases the rate of diffusion

Question 17

why is the rate of diffusion inversely proportional to the thickness of the surface

Answer 17

as the membrane surface gets thicker the rate of diffusion slows down

Question 18

why is the rate of diffusion directly proportional to the concentration gradient

Answer 18

a steeper concentration gradient increases the rate of diffusion

Question 19

what does the maintenance of a steep concentration gradient for oxygen and CO2 depend on

Answer 19

ventilation
transport system

Question 20

what is meant by diffusion of oxygen during ventilation of the alveoli

Answer 20

oxygen is brought into the alveoli (higher concentration inside alveoli than outside in capillaries)
reverse is true for CO2

Question 21

what is meant by diffusion of oxygen during a transport system

Answer 21

oxygen is diffused into the blood then is taken to the heart and tissue
(lower concentration in lung capillaries than in alveoli)
reverse is true for CO2

Question 22

how are the lungs speciallised for efficient gas exchange

Answer 22

large surface area (many alveoli)
large surface area of capillaries
thin alveoli walls
shorter diffusion pathway
ventilation of blood to maintain steep concentration gradient