The Respiratory System Flashcards
Structure: the upper airways are divided into…
Upper and lower
The upper airways begin in the nasopharynx
Inhaled air travels down the larynx to the trachea
Function:
To get air into the body - oxygen into bloodstream to working muscles (living tissues)
Remove waste - carbon dioxide from body
The lungs are the organs that…
Allow us to breathe
Each lung is joined to a main bronchus, which is then…
Attached to the trachea
The lungs are surrounded by a thin membrane called the…
Pleural membrane (thin moist membrane, stops any friction when expanding and relaxing, prevents/reduces damage)
Each lung is divided into regions called…
Lobes
Lungs have a soft, spongy texture that allows then to stretch as we take a breath -
Herring Breuer Reflex
Lung tissue has a very rich….
Blood supply
The rich blood supply allows…
As much blood as possible to pass through the alveoli for oxygenation
The oxygenated blood travels to the heart to be pumped to the…
Body tissues
Deoxygenated blood containing waste carbon dioxide travels to the heart, oxygenated blood to the body…
Double pump
Movement of blood between the heart and lungs =
Pulmonary circulation
Respiratory muscle to contract and relax in order to move air into and out of the lungs…
Intercostal muscles
Diaphragm
(During exercise)
Sternocleidomastoid (mastoid)
Scalenes
Pectoral minor
Mechanisms of breathing, inspiration:
Diaphragm contracts (flattens)
Intercostal muscle contract pulling rib cage up and out
Volume of chest cavity increases
Pressure in chest cavity reduces (pulls air in)
*stretch enables even more air in - Herring Breuer Reflex
Mechanisms of breathing: expiration
Diaphragm relaxes: returns back to dome-like shape
Intercostal muscles relax: lowers ribcage
Mastoids relax
Volume of chest cavity decreases
Pressure in chest cavity increases pushes air out
Structural features of lungs that assist diffusion:
- Large surface area (for alveoli)
- Large blood supply
- Thin membrane for diffusion/1 cell thick
- Short distance for diffusion
- Layer of moisture
- Small capillaries = slower transit time = more time for diffusion
How does oxygen get into the tissues?
Alveoli are covered with capillaries
Oxygen from air is taken up into the blood within the capillaries, then into larger blood vessels to heart
Oxygenated blood is lumped into blood vessels to supply body’s tissues
Oxygen is released - blood now deoxygenated
Gaseous exchange: oxygen
The addition of oxygenated to the blood and the removal of waste carbon dioxide from it
Gaseous exchange takes place in alveoli
Gaseous exchange: carbon dioxide
Carbon dioxide is released from the cells and taken up by tissue capillaries
Gas exchange takes place at the alveoli and capillaries, and tissues and capillaries
Diffusion:
Gases tend to spread themselves out evenly
The membrane has holes in it big enough to allow gas molecules
through so that diffusion can occur
Semi-permeable membrane = allows small molecules through
Diffusion will occur across the membrane in order to equal the pressure of gases on each side f the membrane
The difference in pressure of gas across a membrane is called the diffusion gradient
Partial pressure of oxygen in alveoli =
100mmHg
Partial pressure of oxygen in blood =
40mmHg
Partial pressure of carbon dioxide in alveoli =
40mmHg
Partial pressure of carbon dioxide in blood =
45mmHg
Diffusion at the muscle site:
Oxygen is carried to the muscles in the blood by haemoglobin
Capillaries surround he muscles and as blood flows slowly past the cell walls or he muscle, oxygen dissociates from the haemoglobin into the muscle cell and combines with myoglobin - then to mitochondria
The diffusion of oxygen occurs due to the large diffusion gradient from the partial pressures in the blood to the tissue.
PO2 in capillary = greater (105mmHg) than that in the tissues (40mmHg) therefore oxygen diffuses from the blood into the muscle site along a diffusion gradient of 65mmHg
Carbon dioxide is diffused out f the muscle site into the capillaries as the pCO2 in the tissues = 45mmHg is higher than in the capillary = 40mmHg
Causes the movement of carbon dioxide from the muscle site into the bloodstream along the slight diffusion gradient
Diffusion at the alveoli:
Oxygen in capillaries = low pO2 40mmHg
Oxygen in alveoli = 100mmHg
Large diffusion gradient
Carbon dioxide in blood = 45mmHg
Carbon dioxide in alveoli = 40mmHg
Slight diffusion gradient
