Gas Exchange Humans Flashcards
Topic 2 G.2
The thorax is the human
chest cavity
thorax consists of (8)
- ribs
- intercostal muscles
- diaphragm
- trachea
- bronchi
- bronchioles
- alveoli
- pluriel membranes
gas exchange surface in humans are the
lungs
adaptations of lungs for good gas exchange (4)
- large surface area
- thin walls
- good ventilation with air
- good blood supply
ribs
bones that protect internal muscles like the lungs
intercostal muscles
muscles between the ribs that control the ribs’ movement causing inhalation and exhalation
diaphragm
sheet of connective tissue/muscle at bottom of thorax that helps change the volume of thorax to allow inhalation and exhalation
trachea
windpipe that connects mouth and nose to the lungs
bronchi
large tubes branching off of trachea with one connecting to each lung
bronchioles
bronchi split to form smaller tubes called bronchioles in the lungs connected to alveoli
alveoli
tiny air sacs surrounded by capillaries where gas exchange takes place
pleural cavity
fluid filled space between pleural membranes which reduces friction and allows lungs to move freely
when you breathe in, the diaphragm and intercostal muscles
contract
when you breathe in thorax volume
increases
when you breathe in, pressure _____ bringing air ___
decreases
in
when you breathe out, intercostal muscles and diaphragm
relax
thorax volume _____ when you breathe out
decreases
when you breathe out, pressure ____ so air is forced ___
increases
out
External intercostal muscles, pull the rib cage ___
up
Internal intercostal muscles pull the ribcage ___
down
During inhalation
The diaphragm contracts and flattens
The external set of intercostal muscles contract to pull the ribs up and out:
This increases the volume of the chest cavity (thorax)
Leading to a decrease in air pressure inside the lungs relative to outside the body
Air is drawn in
during exhalation
The diaphragm relaxes it moves upwards back into its domed shape
The external set of intercostal muscles relax so the ribs drop down and in
This decreases the volume of the chest cavity (thorax)
Leading to an increase in air pressure inside the lungs relative to outside the body
Air is forced out
adaptations of alveoli for gas exchange (5)
- thin, one cell thick walls to minimise diffusion distance
- surrounded by capillaries to ensure a good blood supply
- moist lining , A layer of moisture on the surface of the alveoli helps diffusion as gases dissolve
- walls are permeable, so gases can diffuse across easily
- well ventilated, maintains high levels of oxygen and low levels of carbon dioxide in the alveolar air space, meaning there is a steep concentration gradient for diffusion of gases
smoking cigarettes can lead to
diseases in the lungs and can lead to coronary heart disease
smoking damages ?
the walls inside the alveoli, reducing the surface area for gas exchange
what effect does nicotine have on you ( 2– leading to another 2)
narrows blood vessels and increases heart rate leading to increased pressure
- increased blood pressure leads to blood clots forming in the arteries, potentially resulting in heart attack or stroke
carbon monoxide effect on you (1 -1 - 1)
binds irreversibly to haemoglobin, reducing capacity of blood to carry oxygen
- puts more strain on the breathing system as breathing frequency needs to increase
- means that the circulatory system needs to pump blood faster, raising blood pressure and increasing the risk of coronary heart disease and stroke
effect of tar on you
- increses chance of cancerous cells developing in lungs
damages the cilia ( little hairs) in lungs and trachea
these hairs catch dust and bacteria before it reaches the lungs so when the cilia are damaged then chest infections are more likely
PRACTICAL EFFECT OF EXERCISE ON BREATHING
Work out student A’s breathing rate at rest
Count their number breaths for 15 seconds and multiply by 4
Repeat several times to calculate an average
Student A should then exercise for a set time (at least 4 minutes)
Immediately after exercising, count the breaths taken in 15 seconds and multiply by 4 to obtain the breathing rate per minute
Compare the result to the breathing rate at rest to work out the change in breathing rate as a result of exercise
Repeat this last step every minute after exercise for 5 minutes
Repeat the process for student B
Finally, repeat the whole investigation for each student after a period of rest
results of practical should be
frequency of breathing increases when exercising
This is because muscles are working harder and aerobically respiring more and they need more oxygen to be delivered to them
After exercise has finished, the breathing rate remained elevated for a period of time. because the lactic acid that has built up in muscles needs to be removed
What is the trachea made of
cartilage rings that prevent it from falling into itself
what is the trachea lined with (cells)
goblet and epithelial cells which help remove debree and pathogens from the air
what is the larynx
the voice box
what is the pleureal cavity
The fluid filled space between the pleural membranes which reduces friction and allows the lungs to move freely
is inhalation passive or active process
active
is exhalation a passive or active process
passive
ventilation involves ___ and ___ of (2)
contraction and relaxation
diaphram and intercostal muscles
External intercostal muscles, pull the rib cage where ?
up
Internal intercostal muscles pull the ribcage
down
what effect does nicotine have on blood and what does that lead to
hightens blood pressure which leads to blood clots forming in the arteries, potentially resulting in heart attack or stroke
build up of mucus can lead to
damage of cilia. preventing them from beating and removing the mucus and leading to infections
