Mechanics of respiration Flashcards
Quiet breathing
Inspiration is active and expiration is passive.
Deep breathing
Inspiration is active and expiration is active
Side view and anterior view expiration is a
relaxed diaphragm and intercostal muscles.
Side view and anterior view inspiration is a
contracted diaphragm and intercostal muscles.
Laboured breathing inspiration is a
external intercostal muscles and diaphragm flatten.
The 3 accessory muscle are
sternocleidomastoid, scalene, pectorals.
The active process
internal intercostals and abdominal muscles, external obliques, internal obliques, transverse abdominus, rectus abdominus and diaphragm relaxes.
As the thoracic cavity increases it
reduces the pressure and air is drawn in.
The alveolar air
Composition remains relatively constant.
How many alveoli are in the lungs?
600 million
Diffusion is
The exchange of gases occurs when a difference in partial pressure exists across a semi-permeable membrane.
External respiration is
The exchange of gases between the alveoli and the blood.
Internal respiration is
The exchange of gases between the blood capillaries and the body cells.
Oxygen is
Carried in a chemical combination with haemoglobin 98.5% called oxyhaemoglobin. 1.5% dissolved in the plasma.
Carbon dioxide is
Mostly (70%) in the form of bicarbonate ions (H2, CO3) 7% dissolved in the plasma, 23% as carbohaemoglobin.
The control of respiration is
Mainly involuntary, voluntary control during some activity
The medulla is
inspiratory and expiratory neurons involved in the action of breathing in and out and the smooth transition between the two.
The pons are
-two areas called the apneustic and pneumotaxic
The Pneumotaxic
send inhibitory impulses to the MEDULLA that stops inspiration and initiates expiration.
Chemorereceptors
receptors which respond to changes in PO2 and PCO2 in the blood and cerebrospinal fluid.
Where are the central chemoreceptors situated?
the MEDULLA OBLONGATA
Where are the Peripheral Chemoreceptors situated?
in the arch of the aorta and carotid bodies
PaCO2
Partial pressure of arterial carbon dioxide.
Where are stretch receptors situated?
in the thoracic walls.
