gas exchange in humans 3.3.2 Flashcards
name parts of the respiratory system
trachea
bronchus
bronchioles
alveoli
lung
rib
intercoastal muscles
diaphragm
features of trachea
ciliated epithelium
goblet cells
rings of cartilage
what does the bronchus contain
cilia and mucus
lung features
enclosed in a pleural membrane
pleural fluid lubricates lungs
features of alveoli
collagen and elastic fibres between them
lined with squamous epithilia
phagocytes inside
features of goblet cell
cilia
secretory vesicles containing mucin
lots of mitochondria and ribosomes
function of mucus
traps dust and bacteria
function of cilia
beat regularly to move micro organisms and dust particles along with mucus
function of cartilaginous rings
give the trachea support and rigidity
function of epiglottis
closes over windpipe while eating to prevent food entering the airway
function of squamous (flattened) epithelium
means diffusion pathway is shortened
5 adaptations of alveoli
large surface area
diffusion gradient maintained from constant ventilation
1 cell thick
red blood cells slowed as they pass next to alveoli
red blood cells flattened against capillary walls
order of structures O2 passes through into the capillary
alveolus
alveolar epithelial wall
gas exchange membrane
capillary endothelium
capillary
red blood cell
what is surfactant
a phospholipid that coats the surfaces of the lungs
function of surfactant
prevents alveoli from sticking together and collapsing
order of occurrence during inspiration
diaphragm contracts and flattens
external intercostal muscles contract, pulling the ribs up and out
thorax volume increases
pressure in lungs decreases
air is pushed in to equalise the pressure
order of occurrence during expiration
diaphragm relaxes and forms dome shape
external intercostal muscles relax pulling ribs down and in
thorax volume decreases
lung pressure increases
air is pushed out to equalise pressure
what is meant by recoil
elastic tissue can stretch
recoils to an unstretched position
engages then collapses the lungs
pulmonary ventilation rate equation
PV = tidal volume (dm3) x breathing rate
purpose of spirometry
used to measure lung function (capacity of human lungs)
can be used to diagnose lung diseases
define tidal volume
the volume of air breathed in and out without conscious effort
define ventilation rate
number of breaths per minute
define inspiratory reserve volume
the additional volume of air that can be inhaled with maximum effort after a normal inspiration
expiratory reserve definition
the additional volume of air that can be forcibly exhaled after a normal exhalation
vital capacity definition
the total volume of air that can be exhaled after a max inhalation
residual volume definition
the volume of air remaining in the lungs after max exhalation (lungs can never be fully emptied)
total lung capacity =
vital capacity + residual volume
adaptations of mammalian breathing system
alveoli provide a large surface area
walls of alveoli thin to provide a short diffusion pathway
walls of capillary thin provides a short diffusion pathway
walls (of capillaries / alveoli) have flattened cells
cell membrane permeable to gases
many blood capillaries provide a large surface area
intercostal muscles to ventilate lungs
wide trachea efficient
flow of air
cartilage rings keep airways open
