Gaseous Exchange Flashcards
Gaseous exchange?
The exchange of oxygen and carbon dioxide across gaseous exchange surface
Molecules move from area of high concentration to area of low concentration until equilibrium is reached
2 reasons why gaseous exchange is essential
-main function of a Respiratory system is to absorb oxygen from the atmosphere and make it available to the cells for respiration
-CO² is released by the cells during cellular respiration and must be removed. An increase on CO² in the body can lower the pH of body fluids
Requirements for gaseous exchange
- large surface(provide O² and get rid of CO²)
- thin surface(ensure rapid diffusion of gases)
- moist surface(prevent cells from drying & ensure gases can diffuse in a dissolved state)
- well ventilated organs(fresh supplies of air & to remove air containing CO²)
- well protected surface(prevent drying and damage)
- surface must have transport system(efficient transport)
What make up the air passages?
The nostrils, nasal passages, the trachea, bronchi and bronchioles
The nostrils and nasal passages
2 nostrils lead to 2 nasal cavities
3 turbinate bones
•blood vessels warm air
•cilia remove dust particles
•mucus moistens air
The trachea
•tubular passage way for air
•has C-shaped cartilage rings– strengthen and keep trachea open
•lined with ciliated columnar epithelial and goblet cells(secrete mucus)
•mucus traps dust
•cilia drive out dust-laden mucus
The bronchi and bronchioles
Bronchus
•similar structure to trachea
•allows air in and out of each lung
Bronchioles
•small tube leading to alveoli
•smallest brochioli do not have cartilage rings
Adaptations of air passages
Nostrils lined hy hair– remove dust from air that enters
Nasal passages lined with ciliated columnar tissue with goblet cells– secrete mucus that traps dust and germs
Cilia of ciliated columnar tissue– beats to drive mucus, lagen with dust and germs, out of air passages
Cartilage rings of trachea– keep trachea and bronchi open at all times
C-shaped Cartilage rings with incomplete portion of Cartilage in contact with the oesophagus– prevents choking
Epiglottis
Lid-like structure
Closes the opening leading to trachea when swallowing
Prevents objects going down the “wrong tube”
Larynx
Voice box
When air passes through, sound is made
Teeth, lips etc create speech from the sound
Pleura
Double membrane enclosing lung and lining inside of thoracic cavity
Has fluid that prevents friction between ribcage and lungs during inhalation and exhalation
Ribs(rib cage)
Protection
Intercostal muscles
Facilitates inhalation and exhalation
Lungs
Spongy(due to air sacs) cone-shaoed organ
Right lung has 3 lobes
Left lung has 2 lobes
Diaphragm
Muscle separating thoracic and abdominal cavities
Raised- lung pushes upwards and air is forced out(exhalation)
Lowered- lung pulled downwards, low pressure created, air rushes in(inhalation)
