Chapter 4 - "The Respiratory System" Flashcards
respiratory system
the system responsible for taking in oxygen and releasing carbon dioxide using the lungs
the respiratory system consists of
nose, pharynx, larynx, trachea, lungs, bronchi, bronchioles
the nose and nasal cavity are lined with
cilia and mucous membranes
pharynx (throat)
the region from the nasal cavity to the top of the oesophagus
epiglottis
a flap of cartilage that covers the trachea while swallowing
larynx (voice box)
a cartilaginous chamber that joins the pharynx and trachea
trachea (windpipe)
air passage extending from the larynx into the thorax
bronchi
two short branches located at the lower end of the trachea t
bronchioles
progressively smaller tubular branches of the airways
primary bronchi
the first branches of the trachea, there are two primary bronchi, one for each lung
secondary bronchi (lobar bronchi)
branches of the primary bronchi that lead to each lobe of the lung
tertiary bronchi (segmental bronchi)
branches of the secondary bronchi that divide into bronchioles
terminal bronchioles
smaller branches of the bronchioles
lungs
two spongy organs, enclosed by the diaphragm and rib cage and responsible for respiration
mediastinum
the space between the lungs
visceral pleura
inner layer of pleura that covers the surface of each lung
parietal pleura
the outer layer of pleura that lines the inside of the chest
pleural fluid
liquid layer filling the space between the visceral and parietal pleura
alveoli
tiny sacs of lung tissue specialised for the movement of gases between air and blood
ribs
bones in the chest that protect the heart and lungs.
intercostal muscles
the muscles between the ribs
intercostal muscles function
move the ribcage upwards and outwards to increase the volume of the chest cavity and thus the lungs when breathing in
diaphragm
a dome-shaped muscle that separates the chest from the abdomen
diaphragm function
contracts and flattens downwards to increase the volume of the chest cavity and thus the lungs when breathing in
ventilation
the movement of air in and out of the lungs
inspiration
the process of taking air into the lungs
expiration
the process of exhaling air out of the lungs
1st step of respiration
intercostal muscles contract/relax
ribcage moves up and outwards/down and inwards
diaphragm contracts/relaxes
2nd step of respiration
lung volume volume increases/decreases
3rd step of respiration
air flows from higher pressure to lower pressure outside/inside the lungs
1st reason why the lungs well suited for gas exchange
- the alveoli give the lungs a huge internal SA so that large amounts of gases can be exchanged in a relatively short amount of time
2nd reason why the lungs well suited for gas exchange
each alveolus is well supplied with blood vessels, so that as much blood as possible is close to the air in the alveolus.
the continuous flow of blood helps maintain a difference in concentrations of oxygen and carbon dioxide between the blood and air in the lungs
3rd reason why the lungs well suited for gas exchange
the membrane that forms the alveolus wall is very thin, so that gas molecules do not have far to travel when moving in and out of the blood
why are the lungs positioned deep inside the body?
to prevent excessive evaporation of the fluid that covers the respiratory surfaces
why is it important that the alveolus membrane has moisture?
bc gases can only diffuse in and out of the blood when dissolved by fluid
the blood in the capillaries surrounding the alveoli brought to the lungs by
the pulmonary artery
for diffusion of gases in and out of the blood, there must be a concentration gradient, which is
a difference in gas concentration between the air in the alveoli and blood in the capillaries
the concentration gradient of oxygen and carbon dioxide is maintained by
- the constant flow of blood through the capillaries
- the movement of air into and out of the alveoli as we breathe in
inspired air contains
- 95% oxygen
0. 04% carbon dioxide
expired air contains
- 80% oxygen
4. 30% carbon dioxide
emphysema
a disease usually caused by long term exposure to irritating particles in the air taken into the lungs
emphysema is contracted typically by
smokers
people who work with a lot of dust
people who live in highly polluted cities
how does emphysema work?
the irritating particles damage the alveoli, causing them to lose their elasticity
this loss of elasticity causes them to often be replaced with fibrous tissue and break down
it also causes the lungs to be constantly inflated, making breathing a voluntary task
the typical sufferer of emphysema has 2 problems
inadequate SA for gas exchange
difficulty in ventilating the lungs
lung cancer
the development of a mass of cells (tumour) that divides in an uncontrolled way
lung cancer is contracted typically by
exposure to asbestos fibres and other pollutants
tobacco smoking
tobacco smoke is both
an initiator of the cancerous growth
a promoter of the growth of the tumour
how does lung cancer work?
inhaled smoke particles constantly irritate the mucous membranes that line the air passages, which results in the excessive production of mucus
cells at the base of the membrane begin to divide more rapidly and the accumulating mucus cannot be removed
the trapped mucus causes ruptures to the alveoli, which results in emphysema and the ‘smokers cough’
