Respiratory System- Structure and Function Flashcards
Describe the pathway of air
Nasal cavity, pharynx, larynx, trachea, epiglottis, lungs, bronchi, bronchioles, alveoli
Describe the Nasal Cavity
We breathe air in. Hairs filter out dust
What is the Pharynx
It’s the pathway for for and air
Describe the Larynx
Known as the voice box, contains vocal chords
Describe the Trachea
Known as the windpipe. It’s 12cm long. Rigid rings of cartilage to prevent collapse
Describe the Epiglottis
Small flat out cartilage which closes over the top of trachea when you swallow food.
Describe the lungs
Allow oxygen to be drawn into the body. The lungs occupy most of the thoracic cavity. They extend down to the diaphragm
Describe the bronchi
Branch off the trachea and carry air to the lungs
Describe the bronchioles
Small airways that extend from the bronchi. They connect bronchi to the alveoli
Describe the alveoli
It’s the site of gaseous exchange
Describe gaseous exchange
Where O2 is diffused through the alveoli into the blood capillary
Where CO2 is diffused from the blood capillary into the alveoli
What are the characteristics of alveoli
- 1 cell thick
- Short diffusion pathway
- Semi-permeable membrane
- Good blood supply
- Small in size, large in amount
- Large surface area
Describe the diaphragm
A flat muscle located beneath the lungs which supports the mechanics of breathing.
What happens to the diaphragm when we inspire
It contracts and pulls down
What happens to the diaphragm when we expire
Relaxes and rises into dome shape
What are the internal intercostal muscles
They lie inside the ribcage. They draw the ribs down and in. Decreasing the volume of the chest cavity, forcing air out if the lungs when breathing out
What are the external intercostal muscles
Muscles lie outside the ribcage. They pull the ribs up and out. Increasing the volume of the chest cavity and drawing air into the lungs when breathing in
Describe gaseous exchange
When BR and Depth increases, air and O2 goes through gaseous exchange.
It occurs by diffusion between air in the alveoli and blood in capillaries surrounding their walls
Describe the movement of CO2
Blood enters capillaries from the pulmonary artery. Here it has a lower O2 PP and a higher CO2 PP then the air in the alveoli
Describe the movement of O2
It diffuses in blood via the surface of alveoli, through the thin walls if the capillary and into the bloodstream now oxygenated; it latches into haemoglobin. O2 moves from high PP to low PP
