Human Gaseous Exchange Flashcards
Gaseous exchange ?
A process whereby oxygen diffuses across a respiratory surface in one direction and carbon dioxide in the other direction
The 4 things that make up the breathing systems
Air passages
Lungs
Breathing muscles
Breathing center in brain
What are air passages lined with?
Mucus membrane made up of ciliated columnar epithelium
What secrets the mucus?
Goblet cells
Nasal cavity?
Air is drawn into nasal cavity where it is filtered, moistened & warmed to body temperature
Epiglottis ?
Small flap of cartilaginous tissue that closes air passage when food is swallowed
Where is the trachea situated?
In front of oesophagus
Wider part at the top of the trachea is known as the ?
Larynx
- 2 vocal chords in cartilaginous box
- elastic bands vibrate to produce sounds when air flows over them
What keeps the trachea open?
C- shaper rings of cartilage
- open side of C is next to oesophagus which allows it to expand when food passes down
Inner lining of trachea produces mucus & covered in cilia. Why?
To catch dust particles & germs which are sent upwards & coughed out
Trachea then separates into ?
Left & right bronchus
Bronchus –> _______
Bronchioles
Bronchioles –> _______
Alveolar ducts into alveoli
Name of the space between the two lungs
Mediastinum
What membrane surrounds each lung?
Pleural
How many lobes does each lung have & why?
Right - 3 - lies further away from the heart
Left - 2
Name the two sets of muscles used for breathing
Diaphragm
External & internal intercostal muscles
What does the pleural fluid do ?
Prevents friction
Many blood capillaries are wrapped around the outside of the alveoli. What are these walls made up of ?
Single layer of squamous cells
Air will ONLY move in & out of the lungs if there is a ___________ between the air in the atmosphere & air in the lunges
Difference in air pressure
Inspiration?
- air pressure inside lungs must be lower
- contraction of external intercostal muscles cause ribcage to move upwards & outwards
- diaphragm contracts & becomes flat in order to enlarge thoracic cavity
- volume of thoracic cavity & lungs increase
- causes air to flow into the lungs
Expiration?
- external intercostal muscles relax causing ribcage to move downwards & inwards
- diaphragm relaxes & becomes dome shaped
- volume of thoracic cavity & lungs decrease
- pressure in the thoracic cavity & lungs increase
- air will flow out of lungs
Blood in capillaries have a:
Low concentration of ______
High concentration of _______
Low - oxygen
High - carbon dioxide
Oxygen will diffuse from where to where ?
Air in the alveoli through the gas exchange membranes into the blood
