Respiration

• The respiratory system includes the respiratory airways which include the upper respiratory tract which consists of the nose, pharynx, and larynx, and the lower respiratory tract which consists of the trachea, bronchi, and alveoli, the site for gas exchange between air and blood.
• The lungs contain the alveoli.
• The right lung has 3 lobes, and the left lung has 2 lobes.
• The primary function of the respiratory system is to obtain O2 from atmospheric air and to remove CO2.
• The respiratory system maintains acid-base balance by altering the amount of CO2 expired.
• The respiratory system defends against inhaled foreign matter by the presence of cilia and mucus secretion.
• The respiratory system enables speech and singing.
• The nose serves as the organ of smell.
• Tidal volume (TV) is the volume of air entering or leaving the lungs during a single breath under resting conditions.
• Inspiratory reserve volume (IRV) is the extra volume of air that can be maximally inspired after the normal tidal volume.
• Expiratory reserve volume (ERV) is the extra volume of air that can be actively expired after the resting tidal volume.
• Residual volume (RV) is the volume of air remaining in the lungs after the most forceful expiration.
• Dyspnea is the difficulty in breathing.
• Cyanosis is the bluish discoloration of the skin and mucous membrane (Lips, nail beds, ear lobes), appearing when the amount of reduced Hb in capillaries is increased above 5 gm/100 ml blood.
• Orthopnea is dyspnea only in the recumbent position.
• Hyperpnea is an increase in the rate or depth of respiration.
• Apnea is the temporary stoppage of breathing.
• Hypoxemia is the decreased O2 in arterial blood.
• Types of Hypoxia include: Hypoxic hypoxia, Anemic hypoxia, Histotoxic hypoxia, and Stagnant (ischemic) hypoxia.
• Stagnant hypoxia causes include: Reduction of blood supply to tissues may be generalized as in circulatory shock and congestive heart failure, or localized as in local vascular spasm.
• Hypoxic hypoxia causes include: Decreased O2 tension in inspired air, leading to decreased arterial PO2, as seen at high altitude.
• Anemia hypoxia causes include: Anemia.
• Hypercapnia is the excess CO2 in the arterial blood.
• Histotoxic hypoxia causes include: Inhibition (or block) of cellular oxidative enzyme, most commonly in cyanide poisoning.
• Eupnea is the normal breathing during rest.
• Clinical manifestations of hypoxia include: Headache, Easy fatigability, Drowsiness, Loss of appetite, Nausea & vomiting, Tachycardia, Tachypnea.
• Hypoxia is the insufficient oxygen supply at the cells.
• Tachypnea is rapid shallow breathing, an increase in the rate of respiration with a decrease in the depth.
• Hypocapnia is the decrease in CO2 in the arterial blood.