chapter 7- exchange surfaces and breathing Flashcards
what are the 2 types of intercostal muscle
external and internal
why can singled celled organisms survive
because exchange can take place through the cell surface as there is a short diffusion pathway, metabolic activity is low and so o2 demands and co2 production is low, there is a high sa:v
as organisms get larger (3)
metabolic activity inc
o2 demand inc
co2 production inc
as organisms get larger the distance between cells increases meaning
the cells where o2 is needed and the supply of o2 is too far for diffusion to take place
as organisms get bigger what happen to the sa:v wmt
it decreases wmt gases cant be exchanged fast enough or in large enough amounts for the organism to survive
what is the pathway of air in mammals
nasal cavity
pharynx and larynx
trachea
left or right bronchus (bronchi)
bronchioles (pri, sec, ter)
respiratory bronchioles
alveoli
how many lobes does the right lung have
3
how many lobes does the left lobe have and why
2 due to the position of the heart
what is the total diffusion distance for gases
2 cells
what is the role of the nasal cavity in gas exchange (3)
blood warms the air
mucus traps particulates
humidifies air to protect more delicate structures in the lungs
adaptations to nasal cavity for exchange
good blood supply
large sa
goblet cells secrete mucus
moist surfaces (due to surfaces)
hoe long is the trachea
10-12cm long
what is the role of the trachea
to funnel air into and out of the lungs
adaptations to trachea
ciliated epithelium down to bronchi (columnar epithelium)
goblet cells that secrete mucus
c shaped rings of hyaline cartilage which is strong and flexible
adaptations of bronchi
full ring of cartilage
lined with cilia and goblet cells
some smooth muscle
as the diameter of structure decreases the amountof smooth muscle
increases
why is it neccessary that the respiratory system is specialised
size is very large (small sa:v)
high metabolic demand
to remove carbon dioxide
why might the diameter of bronchioles reduce
inflammation (eg diseases eg asthma) excess mucus
each lung is surrounded by a
pleura membrane which secretes pleura fluid into the pleura cavity lubricating each lung
it is a double membrane
why are surfaces moist
so that gases can dissolve to aid diffusion, eg gases dissolve in the water film in around the alveoli
adaptations of bronchioles
more smooth muscle
elastic fibres
lined with cilia and goblet cells
lacks cartilage so relies on air to maintain shape
elastic fibres ……+……. whereas smooth muscle …..+……
stretches and recoils
contracts and relaxes
adaptation of alveoli
squamous epithelium
1 cell thick(short diffusion pathway)
abundance (300-500million)
good blood supply lots of capillaries
collagen and elastic fibre
surfactant
Capillaries have a narrow lumen. How does this support their function?
It means that blood cells press against the side wall, reducing the diffusion distance to nearby cells and increasing the rate of diffusion.
what does lung surfactant do
function of gobllet cells in the gas exchange system in mammals
to secrete mucus by exocytosis which traps bacteria and removes them from the lungs/stops from reaching the lungs, mucus is a glycoprotein
role of smooth muscle cells in the gas exchange system in mammals
can contract decreasing trachea/bronchiole diameter propelling air upwards from the lungs at force, adjusting the size of airways, relaxes to open/dilate bronchiole and trachea
what is the role of squamous epithelial in the gas exchange system in mammals
ease of rapid gas exchange, smooth low friction surface, flattened/wider than tall, made up of type 1 pneumocytes
what is the role of ciliated cells in the gas exchange system in mammals
to waft/beat rhythmically to move foreign particles/ mucus out of the body
function of cartilage in the gas exchange system in mammals
prevents bursting of airways which could happen due to pressure changes, prevents collapse of airways, low resistance to air movement, in the trachea and bronchi it is strong and flexible with closely packed collagen
what is the function of elastic tissue in the gas exchange system in mammals
to stretch and recoil to prevent alveoli form bursting, the recoil helps to expel air during exhalation, expiration is a passive process
what do type 2 pneumocytes do
secrete pulmonary surfactant reducing surface tension and increasing stability
what is ventilation
a term used to describe breathing where air is constantly moving in and out of the lungs
why does ventilation have to be maintained
to maintain a concentration gradient in alveoli continually cycling air into the alveoli from the atmosphere
gases move from a region of
high pressure to low pressure
describe inspiration
(7)
diaphragm muscles contract and flattens
volume of thoracic cavity/lungs increases
external intercostals contract
ribs move up and out
pressure decreases to lower than atmosphere outside lungs and so air will move into the lungs
active process
describe expiration
diaphragm muscles relax back into dome shape. volume of lungs/thoracic cavity reduces
internal intercostal muscles contract but only during forced expiration
ribs move inwards and downwards
external intercostals relax
elastic fibres in trachea, bronchi, bronchioles and alveoli recoil to decrease volume
pressure increases
what are the additional muscles for inspiration
sternocleidomastoid and pectorals minor
what are the additional muscles for expiration
abdominal muscles internal intercostals
what stimuli causes a baby to take its first breath
temperature, sound, light, co2 levels, fluid to air `
why do premature babies have trouble breathing
they dont have the lung surfactant to work against the surface tension inside the lungs and so artificial surfactant is added
what part of the brain coordinates breathing
medulla oblongata
resuscitation uses exhaled air how is this still effectuve
the compostion of air breathed in contains 21% o2 breathing out it is 16% so it is still a lot
what is detected to regulate ventilation
pH
what detects the pH of the blood
chemoreceptors
ventilation in humans changes in response to
levels of physical activity as the bodys energy demands are increased
ventilation is an example of
negative feedback because has co2 conc increases breathing rate increases to bring levels down (level not to increase difference (pos))
what are some ways ventilation in humans can be measured
simple obvs (counting breaths in a min)
chest belt and pressure meter (recording the rise and fall of the chest)
spirometer
what is the formula for pulmonary ventilation
tidal volume x ventilation
units for pulmonary ventilation and other
PV dm3mmin-1
tv dm3
vr min-1
what is tidal volume
the volume of air that moves in and out of the lungs with resting each breath
usually 1/2 a liter
what is ventilation rate
no of breaths in 1 min usually 12-20
what is pulmonary ventilation
total volume of air that is moved into the lungs during one minute
what is asthma
a common chronic inflammation of the airways to the lungs, the smooth muscle becomes tightened
what can cause asthma
recurring environmental triggers including smoke, allergens, cold air, medications, arthropods eg dust mites
gases move from a
region of high pressure to a region of low pressure
what does spirometry measure
the amount and rate of air a person breathes in order to diagnose illness or determine a progress of treatment
a spirometer is a device that detects
the changes in ventilation and presents the data on a digital display
how can a balloon be used to measure the volume of air in a single breath
breathe one breath into a balloon, submerge the balloon underwater and measure the volume of water displaced (1ml=1cm3)
hoe can you make using a spirometer valid
only breathe through the mouth had have a clip on the persons nose
what are the components of a spirometer
static lower tank is filled with water, mobile upper half is tank is full with o2, trace drawn (with trace marker) of revolving drum or electronic display, canister of soda lime
why is there a cannister of soda lime on a spirometer
to remove co2 produced so that the concentration is kept at a safe level
breathing out into a spirometer will cause what
the upper half with rise as you breathe out into the tank, volume of air in spirometer increases
breathing in from a spirometer will cause what
the upper half to fall, volume of air in spirometer decreases
the trace marker on a spirometer is attached to the
mobile upper half
on a spirometer trace/graph, if volume of air inside the spirometer is on the x axis, what will happen to the line during inspiration and expiration
inspiration- it will go down
expiration- it will go up
on a spirometer graph, if volume of air inside the lungs is on the x axis, what will happen to the line during inspiration and expiration
inspiration- it will go up
expiration- it will go down
why is the volume inside the spirometer slowly decreasing
how to measure TV on a spirometer graph
peak to trough
how to calculate breathing rate
number of breaths divided by time
describe the 2 ways exercise will influence ventilation
increase ventilation rate so that there is a more continuous exchange of gases
increase tidal volume so that more air can get into the lungs to be exchanged
is the residual volume of air stale
no because it is being replaced all the time
what is the purpose of the residual volume
to prevent the lungs from sticking together
what is total lung capacity
the volume of air in the lungs after maximal inhalation (6l in a normal adult male)
what is vital capacity
volume of air you can exchange by the lungs via maximal inhalation and exhalation
what is residual volume
volume of air that is always present in the lungs
on a spirometer trace which reserve volume is always next to residual vol
expiratory reserve vol
what factors contribute to a persons lung capacity and ventilation rate
height (a taller person will have wider shoulders and so a larger chest capacity)
location eg altitude
lifestyle eg smoking
age, gender
what does COPD stand for
chronic obstructive pulmonary disease
what is COPD
chronic inflammatory lung disease which can involve a combination of diseases, it causes obstructive airflow to the lungs
COPD is mostly found in which kind of people
older people
symptoms of COPD
breathing difficulty
cough
mucus (sputum) production
wheezing
land animals are also called
terrestrial animals
how does o2 availability compare in water and in air
the amount of o2 dissolved in water s less than in air, H2O is heavier than air and so lots of energy is needed to move water of respiratory exchange surface
how do gas exchange systems compare in simple and complex organisms
simple: large sa:v for gas exchange by diffusion
complex: o2 from H2O through gills, the complexity of the gill structure correlates to the o2 requirements
on fish what is the thing called that covers the gills
the operculum
what is the operculum
a gill cover that is moveable and reinforced with rays of bone
what key features can be seen in a fish dissection
gill arch
filaments
where does gas exchange occur in fish
gill plates
each gill…… is attached to 2 stacks of…..
arch
filaments
on the surface of each filament there are rows of
lamellae
the lamellae consists of a single layer of flattened cells that cover a vast network of
capillaries
what in fish is 1 cell thick
the lamellae and the capillaries
what is the purpose of a counter-current
maintains concentration gradient along the whole length of the capillary. the water with the lowest concentration of o2 is found adjacent to the most deoxygenated blood
what else does the counter-current do
forces water past the lamllae in the opposite direction to the flow of blood as the blood always requires o2 it moves towards the water that always has a higher concentration of o2
what would happen is there was a parallel counter-current
fails to provide a persistent o2 conc gradient and then there will be no futher exchange as the conc gradient will disappear as concs become the same
what happens during inspiration in a fish
muscles contract lowering the floor of the pharynx, volume of buccal cavity increases, pressure decreases and so water enters the mouth
what additional things happen in inspriation in a fish
operculum buldges outwardsm opercular valve close, pressure decreases, water flows into the opercular cavity
insects are per
blood vessels generally contain a layer of collagen this is to
resist changes in pressure
blood vessels generally contain a muscle later, the function is to
contract to control the flow of blood
blood vessels generally contain an elastic layer, the function is to
stretch and recoil to maintain blood pressre
blood vessels are lined with an endothelium layer, how is it adapted to its function
it is smooth to reduce friction with the blood, it is one cell thick to allow rapid diffusion
how is the elastic layer in arteries adapted to its function
thicker than in veins to maintain high bp so that blood reaches the extremeties.
the stretch and recoil helps to smooth pressure csurges resulting from the heartbeat
how is the artery wall adapted to its function
it is thick to help prevent the artery bursting under pressure
how is the valve system in arteries adapted to its function
there are no valves as the constant high pressure helps prevent blood from flowing backwards
how is the lumen in veins adapted to its function
it is large so it can carry a large volume of slow moving blood
how is the muscle layer in veins adapted to its function
