Respiratory System Flashcards
Respiratory system
Allows the body to breathe, bringing oxygen into the body and removing carbon dioxide.
Consists of the lungs and associated structures responsible for gas exchange in the body, bringing air into the body and removing waste products.
Respiratory system functions
brings air from the atmosphere into
the lungs
transfers oxygen into the blood
removes carbon dioxide from the
blood
expels heat and water vapour in the
air breathed out
allows the vocal cords to create
speech as air is breathed out.
Nasal cavity
The nose is the initial pathway for air from outside the body.
Air is warmed and moistened in the nose
The pharynx
This section of the throat is where the backs of the mouth and the nose combine.
The food is channelled into the oesophagus, while the air moves into the larynx.
The air is further warmed here using similar methods as in the nose.
The larynx
This structure is more evident in males with their ‘Adam’s apple’.
The larynx contains the vocal cords that create the voice as air passes through them
The trachea
Often referred to as the windpipe
It sits mostly behind the sternum, so it provides a well-protected medium for the passage of air into the lungs.
The bronchi
The trachea divides into two bronchi
Each bronchus feeds air to one of the lungs
The bronchioles
Each bronchus sub-divides into a series of further sub-dividing bronchioles.
This system of the lungs’ gradually diminishing series of air passages is similar to an inverted tree, with its main trunk moving to a series of
everdiminishing branches, then to the leaves.
The alveoli
These ‘leaves’ of the lungs are microscopic cup-shaped sacs at the ends of the smallest bronchiole.
Each alveolus is only one cell thick and surrounded by a rich network of capillaries that continually exchange oxygen for carbon dioxide and water
The pleura
The pleura covers each lung.
The gap between the membrane and each lung is filled with a fluid that allows the lung to expand and contract with each breath
Minimises friction
The pleura is attached to the inside of
the chest cavity and to the top of the
diaphragm.
Diaphragm
Muscle that helps you breathe in and out
Mechanics of breathing in
Intercostal muscles (around the ribs)
Diaphragm (under lungs)
Both these muscles contract during inspiration
This increases the area of the Chest cavity
Increased area results in decreased Pressure within the Chest cavity
We now have a pressure gradient
Low pressure within the chest cavity and a higher pressure in the outside air.
Pressures move from high to low
Therefore the air moves into the lungs.
Mechanics of breathing out
Intercostal muscles (around the ribs)
Diaphragm (under lungs)
Both these muscles relax during expiration
This decreases the area of the Chest cavity
Decreased area results in Increased Pressure within the Chest cavity
We now have a pressure gradient
High pressure within the chest cavity and a lower pressure in the outside air.
Pressures move from high to low
Therefore the air moves out of the lungs.
Gaseous exchange
Same principle of pressure gradients applies
When we breathe in – high concentration of Oxygen in the lungs – alveoli.
The blood in the capillaries has returned from the body and therefore has a low concentration of
Oxygen
High pressure moves towards Low pressure.
As the walls of both the alveoli and capillaries are thin, gases can pass through – we get a transfer of
oxygen into the blood and removal of CO2
Tidal volume
the amount of air taken (breathed in) OR breathed out in one breathe.
the amount of air increases as the level of exercise increases.
