Breathing/Gaseous Exchange Flashcards
breathing
physical process of taking in O2 and releasing CO2
where does gas exchange occur in plants
via the stomata in leaves and lenticels in stems
4 ways in which the lungs are adapted for gaseous exchange
large surface area
large blood supply
thin walls, freely permeable gases
moist absorbing surface
where are the lungs found
in the thoracic cavity
what protects the thoracic cavity
the ribcage
what are the lungs surrounded by
pleural cavity lined with pleural membranes
function of pleural membranes
secrete fluid which lubricates the lungs and thorax, allowing friction-free movement during breathing
cilia
tiny hairs to move mucus
mucus function 2
filters the air removing dust and bacteria
moistens the air
other function of nose
heats air to 37ºC
function of epiglottis
prevents food from entering the trachea
larynx
voice box
location of voice box
sits at the top of trachea
bronchi and bronchioles have (3)
mucus
cilia
c-shaped rings of cartilage
c-shaped rings of cartilage
to keep the tubes open when the air pressure drops during breathing
5 adaptions of alveoli for gas exchange
thin, elastic walls large surface area moist surface large blood supply well ventilated
thin elastic walls
one cell thick, fully permeable to gases
large surface area
good exchange of gases
moist surface
O2 goes into solution and diffuses in easily
large blood supply
lots of capillaries in close contact, gases only have to diffuse a short distance
well ventilated
air is moved in and out quickly
Inhaled air oxygen
21%
exhaled air oxygen
14%
inhaled CO2
0.03%
exhaled CO2
4%
inhaled H2O
low
exhaled H2O
high
inhaled nitrogen
78%
exhaled nitrogen
76%
the active phase
inhalation as it involves muscle contraction
inhalation first step
intercostal muscles contract and move the rib cage up and out
inhalation second step
diaphragm contracts and drops down (flattens)
volume of thoracic cavity during inhalation
increases
pressure of thoracic cavity during inhalation
decreases
inhalation due to pressure
air flows into lungs
exhalation first step
intercostal muscles relax, so that the rib-cage goes down and in
exhalation second step
diaphragm relaxes and becomes dome shaped
volume of thorax during exhalation
decreases
pressure of thorax during exhalation
increases
exhalation due to pressure
air is forced out of lungs
rate of breathing controlled by
CO2 levels in the blood
normal breathing movements
14-16 breaths per minute
what in the brain controls the breathing
the medulla oblongata
when CO2 level increases
nerve impulses sent to increase rate and depth of breaths
TO INVESTIGATE THE EFFECT OF EXERCISE ON THE BREATHING RATE OF A HUMAN
what do you do
count breaths per minute
TO INVESTIGATE THE EFFECT OF EXERCISE ON THE BREATHING RATE OF A HUMAN
different rates
resting
walk gently
walk briskly
run
breathing disorder
asthma
3 symptoms of asthma
noisy, wheezy breathing, cough
cause of asthma
constriction of the lower bronchioles
inhalation of substances that act as allergens such as pollen, feather, dust, moulds
asthma attack
when the bronchioles become narrow and inflamed and the flow of air is obstructed
prevention of asthma
avoid the allergens that cause an attack
treatment of asthma
inhaling drugs to dilate the bronchioles
