Biology: Gas Exchange: Humans Flashcards
(23 cards)
Outline the structure of the human gas exchange system
-mouth and nose air in, air down trachea -trachea into bronchi into bronchioles
-bronchiole ends have air sacs called alveoli -alveoli surrounded by capillaries
-diaphragm, ribs, intercostal muscles involved in ventilation
Describe the flow of air through the human gas exchange system
-mouth and nose breath air in -air moves down trachea which splits into two bronchi
-bronchi further divided into bronchioles -air sacs called alveoli at bronchiole ends
-alveoli exposed to capillary network -air exchanged at alveoli into bloodstream
What are the seven specialised tissues involved in the human gas exchange system?
-cartilage -surfactant -elastin -goblet cells -smooth muscle -squamous epithelium
-ciliated epithelial cells
Where is cartilage found?
trachea and bronchus
What is the function of cartilage?
strength and prevents collapse when pressure decreases
Where is surfactant found?
coats surface of lungs
What is the role of surfactant?
maintains moisture and reduces surface tension to prevent alveoli collapsing when pressure decreases
Where is smooth muscle found?
trachea and bronchioles
What does smooth muscle allow?
airways to constrict by contraction
Where are goblet cells found?
trachea and bronchioles
What do goblet cells do?
secrete mucus to trap dust and bacteria particles
Where are ciliated epithelial cells found?
trachea and bronchioles
What is the purpose of ciliated epithelial cells?
wafts mucus for removal, clears airways and prevents infection
Where is elastin found?
all of airways and alveoli
Why is elastin needed?
allows lung tissue to stretch and recoil. allows alveoli to return to original shape after exhalation
Where is squamous epithelium found?
alveoli
What is the function of squamous epithelium?
provides short diffusion distance
How is the human gas exchange system adapted?
-thin alveolar epithelium and capillary endothelium -lots of alveoli -narrow capillaries
-lots of capillaries -constant ventilation
Why is thin capillary endothelium and alveolar epithelium important?
short diffusion distance
Why are many alveoli important?
increases surface area
Why are narrow capillaries important?
diffusion time increased, red blood cells slowed
Why are many capillaries important?
circulation constantly removes oxygenated blood, steep concentration gradient
Why is ventilation important?
ensures high concentration of oxygen in alveoli, concentration gradient maintained
