6.6, 6.7, 6.8 human gas exchange

why are terrestrial gas exchange systems internalised?

prevents excessive water loss from the large, moist surface area

where in the respiratory system are there cilia

nostril, bronchi, trachea

cilia move mucus produced by goblet cells. what is the function of this?

traps pathogens and particulates

where else in the female body are there cilia and why?

fallopian tubes- waft and beats egg unto uterus

the lungs are surrounded by thin membranes. what are these called?

pleural membranes

what do pleural membranes secrete and what does this do?

pleural fluid- natural lubricant which makes it easier for the lungs to move when you breathe

what are bronchioles

branching subdivisions of bronchi

what are bronchiole walls made of and what is its function?

muscle lined with epithelial cells- so can constrict to control air in and out of the alveoli

what are alveoli and what diameter?

minute air sacs at end of bronchioles. diameter of 100-300 micrometres

what is the structure of alveoli? (whats it made of)

lined with epithelium. collagen and elastic fibres between each alveolus. gas exchange surface is alveolar membrane

what do elastic fibres allow the alveoli to do?

stretch as they fill with air when inhaling and spring back when exhaling to expel co2 rich air

role of alveoli in gas exchange (5)

lining of thin epithelial cells for short diffusion distance

network of pulmonary capillaries

red blood cells slow down and flatten against capillary wall to absorb oxygen

continuous tidal ventilation and blood flow to maintain favourable concentration gradient

elastic fibres allow alveoli to stretch during inhalation and to expel air

what happens to the intercostal muscles during inspiration?

external contract, internal relax

what happens to the ribs during inhalation

up and out

what happens to the diaphragm during inhalation

contracts and flattens

what happens to the volume of the thorax during inspiration

increases

what happens to the pressure in the thorax in inhalation

decreases

what is the atmospheric pressure in inspiration

greater than pulmonary pressure so air is forced into lungs

what happens to the intercostal muscle during expiration

external relax, internal contract

what happens to the ribs during expiration

down and in

what happens to the diaphragm during expiration

relax and returns to dome shape

what happens to the volume in the thorax during expiration

decreases

what happens to the pressure in the thorax during expiration

increases

what is the atmospheric pressure during expiration

lower than pulmonary, so air is forced out

what structure makes the windpipe stay open, but able to bend?

rings of cartilage

what happens when lung tissue is put into water

float- has air filled tubes

in a living animal, what body movements, draw air into the lungs?

diaphragm contracts, rib cage up and out

in a living animal, what body movements force air from the lungs?

ribs down and in, diaphragm up and returns to concave shape

describe the difference in appearance of healthy and diseased lung tissues

diseased and black and clotty, healthy are smooth and don’t have excessive mucus

3 symptoms of lung disease and explain them

shortness of breath- loss of elasticity as elastin permanently stretched, therefore reduced oxygen levels.

chronic cough- body trying to remove damaged tissue as the cilia is destroyed.

bluish skin coloration- poor rate of gas exchange, low co2 levels

what is this?

emphysema

what is this

anthracosis

how many smokers does emphysema affect and how long does it take to develop

1 in 5 smokers, develops over 20 years

is it easy to diagnose emphysema?

no- impossible to diagnose until lungs are irreversibly damaged

what are the physiological effects of emphysema?

elastin permanently stretched so air cant be forced out if lungs

surface area of alveoli is reduced so very little gas exchange

breathlessness due to lack of oxygen

what percentage of the worlds population have asthma

10 percent

how many deaths each year from asthma

2000

what is asthma stimulated by?

allergens like pets, pollution, cold air

allergens cause white blood cells to produce histamines, what does this cause?

lining of lungs inflamed

cells of epithelial lining secrete lots of mucus

fluid leaves capillaries and enters airways

muscle surrounding bronchioles contracts so constricts airways

what does copd stand for?

chronic obstructive pulmonary disorder

what is copd

a build up of pollution over time can result in the lining of the lungs, trachea and airways inflaming

why are terrestrial gas exchange systems internalised?