The Respiratory system

Published on 4th April 2018

RESPIRATION

Uptake of oxygen by all cells for energy production
Formation of carbon dioxide and water as waste products
Exchange of these gases occurs between:
- the alveoli of lungs and blood capillaries – external respiration
- blood capillaries and all cell walls – internal respiration

ANATOMY

Nasal passages
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Alveoli
Pleura
Diaphragm
Thoracic cavity

BREATHING

Inspiration

Intercostal muscles contract. Ribs move up and out
Diaphragm contracts and flattens. Lungs pulled downwards
Chest Cavity enlarges – so pressure inside chest is lowered and air is sucked in

Expiration

Intercostal muscles and diaphragm relax
Chest cavity decreases in size – so pressure inside chest is increased and air is forced out

Control

Normal rate about 16 x minute
Controlled by chemo receptors in aorta and carotid arteries which monitor levels of gases in blood and send information back to brain
Amount of lung expansion and muscle activity are also monitored by the brain

Additional Information for VTCT Qualification

The nose is separated into 2 nostrils by a plate of cartilage called the septum. There are specialised cells in the roof of the nose
which are stimulated when chemical particles dissolve in the moist mucosal lining as we inhale. Nerve fibres travel from here
towards the special olfactory area of the temporal cortex of the brain where the impulses are interpreted and we become aware
of the smell.
If the smell is one we perceive as pleasant it may increase our appetite and so can play an important role in the digestive
process. Our ability to smell also influences our sense of taste as found when we have a cold! Our sense of smell is a primitive one
and would have been vital to our survival in the past just as it is for wild animals .It also links directly with the emotional part of
the brain and so can evoke powerful memories.

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