The Breathing System in the Human
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Homeostasis
The maintenance of a constant internal environment despite outside fluctuations.
Necessity of Homeostasis
Enzymes, control all metabolic reactions in organisms. They are usually very sensitive to factors such as temperature and pH. The regulation of these factors is essential for optimal metabolism in the organism.
In humans, homeostasis is essential for the following reasons:
- Regulation of blood sugar levels
- The control of the concentrations of respiratory gases in the blood
- Regulation of Heartbeat rate
- Control of the water content in the blood
Breathing in the Human
Breathing is the means by which Oxygen (O2) is passed from the atmosphere into the blood and by which Carbon Dioxide (CO2) and Water (H2O) are passed from the blood into the atmosphere.
Respiratory System
The respiratory system consists of:
1) Lungs - highly vascular and contain many bronchioles, which end in microscopic air sacs called alveoli
2) Air Passages - are present in this order: mouth and nasal passages, pharynx, larynx, trachea, bronchi, bronchioles and alveoli
3) Breathing Muscles-
- Intercostal Muscles - join most of the ribs to one another so that a sheet of muscle covers the rib cage
- Diaphragm Muscles - forms a seal under the lungs, separating them from the rest of the organs of the lower body
Gaseous Exchange
The movement of O2 from the air into the blood and the movement of CO2 from the blood into the air. It occurs in the alveoli of the lungs. Gaseous exchange occurs by diffusion
Mechanism of Breathing
Breathing in the human occurs in 2 stages:
1) Inspiration - the taking in of air from the atmosphere
2) Expiration - the passing out of air into the atmosphere
Inspiration is active (it requires the use of energy). The Intercostal muscles and the Diaphragm contract, causing the rib cage to lift up and out, the diaphragm then flattens. Both of these actions increase the volume of the chest cavity and air flows into the lungs.
Expiration is passive (does not require the use of energy, unless the body undergoes strenuous exercise). The Intercostal muscles relax, lowering the rubs and the Diaphragm muscles relax, thus allowing the Diaphragm to rise up. The actions cause the volume of the chest to decrease, forcing air out. write my paper
