Respiration

4 Processes:

1.Breathing - exchange of air between the lungs and the environment, including inspiration and expiration.

2.External Respiration - takes place in the lungs and involves the exchange of O2 and CO2 molecules between the air and the blood.

3.Internal Respiration- takes place within the body and involves the exchange of O2 and CO2 molecules between the blood and tissue fluids.

4.Cellular Respiration- involves the production of ATP in body cells.

External Respiration

Gas exchange occurs between pulmonary 

capillaries and the alveolus.

Internal Respiration

Gas exchange occurs between the tissues and capillaries.

Breathing Movement

-The movement of gases into and out of the lungs is determined by the difference in pressure between the atmosphere and the thoracic cavity.

-Pressure in the thoracic cavity is regulated by the diaphragm.

-The diaphragm is assisted by the movement of the intercostal muscles.

-Atmospheric pressure - Constant

-Thoracic cavity pressure - Changes

Gas Exchange and Transport

-Gases diffuse from an area of higher pressure to an area of lower pressure. 

-The partial pressure of oxygen is highest in the atmosphere and lowest in the veins and tissues.

-The partial pressure of carbon dioxide is highest in the tissues and veins and lowest in the atmosphere.

Chemoreceptors

Chemoreceptors: a specialized nerve receptor that is sensitive to specific chemicals.

Carbon Dioxide Chemoreceptors

-Chemoreceptors detect the levels of carbon dioxide in the blood. 

-CO2 dissolves in the blood and forms an acid. 

-Special chemoreceptors in the medulla oblongata become activated.

-The medulla oblongata relays messages to the intercostal muscles and diaphragm to increase breathing movements.

-The acceleration of the breathing rate decreases the levels of CO2 in the blood.

Oxygen Chemoreceptors

-Chemoreceptors sensitive to oxygen, is found in the carotid and aortic arteries.

-Specialized receptors primarily responsible for testing low levels of oxygen. 

-The oxygen receptors send a nerve impulse to the medulla oblongata.

-The medulla sends nerve impulses to the intercostal muscles and diaphragm to increase breathing movements.

-Increased ventilation increases blood oxygen.

Disorders of the Respiratory System

1)Bronchitis: inflammation of the bronchial tubes

-Narrowing of air passageways and inflammation of mucus lining in bronchial tubes and decreased air flow 

2)Emphysema: walls of alveoli become inflamed

-Destroy the air sacs

3)Asthma: Narrowing of bronchial tubes and increased mucus

-Increased effort required to exhale than inhale.

4)COPD (Chronic Obstructive Pulmonary Disease):

Emphysema+Chronic Bronchitis = COPD

Increased resistance to airflow through the bronchioles.

Loss of gas exchange, Increased breathing and heart rate.