Respiration / Gas Exchange Flashcards
Path of air
Nose - pharynx - larynx - trachea - bronchi - bronchioles - alveoli
Nose
- adds moisture and warmth to inhaled air
- filter
Pharynx
involved in diverting ingested material into esophagus and away from lungs to prevent choking
Larynx
Contains membrane that vibrates in a controlled manner with the passage of air to create the voice
voice box
Trachea
Carries air through the vulnerable throat protected by flexible but strong rings of cartilage
At the end of trachea, respiratory passage splits into lungs
Alveoli
- Tiny air sacs
- Site of gas exchange in the lungs
- Have thin, moist walls
- Surrounded by cappilaries
- Oxygen passes from the alveolar into the blood by diffusion through the alveolar and capillary walls
- CO2 and H2O pass out
Lungs
- move air between the exterior atmosphere and an interior air space that is close to capillaries
- bound by ribs and chest wall and by the diaphragm on the bottom
- A membrane called a pleura surrounds the lungs
Pleura
Why is air drawn into the lungs by negative pressure?
The internal pressure inside the chest cavity is lower than the air pressure surrounding the body
Inhalation
- AKA inspiration
- ribs - up and out
- diaphragm - down
- creates a larger chest cavity and a vaccum that draws air
Exhalation
- ribs - down and in
- diaphragm - up
- decreases size of chest cavity
- forces air out of lungs
- doesn’t require muscle contraction
Medulla
- Controls breathing rate
- monitors carbon dioxide levels in the blood
- senses changes in the pH of blood
- ph 7.4 or lower and excess CO2
- triggers autonomic nerves from the medulla to increase breathing rate
How is oxygen carried in the human blood?
By the respiratory pigment hemoglobin, which combines loosely with oxygen molecules to form the molecule oxyhemoglobin
Carbonic acid-bicarbonate ion system
Carbon dioxide is carried in the plama as part of the reversilbe blood-buffering carbonic aci-bicarbonate ion system
Maintains the blood at a constant pH of 7.4
