CHAPTER 21

What are the major jobs of the respiratory system?

Brings oxygen into the body, removes carbon dioxide, helps maintain blood pH, allows speaking, aids sense of smell, and filters particles and pathogens.

What is the sequence of air movement and gas exchange in the respiratory system?

Air comes in → oxygen enters blood → oxygen reaches cells → cells produce CO₂ → CO₂ enters blood → CO₂ leaves through lungs.

What is pulmonary ventilation?

Movement of air into and out of the lungs.

What happens during external respiration?

Gas exchange between alveoli and blood; O₂ moves from alveoli to blood and CO₂ moves from blood to alveoli.

What does the conducting zone do?

Moves air but does not perform gas exchange; includes the nose, nasal cavity, pharynx, larynx, trachea, bronchi, and bronchioles.

What is the primary function of the respiratory zone?

Actual gas exchange occurs in this zone, which includes respiratory bronchioles, alveolar ducts, and alveoli.

What is the main purpose of the nasal conchae?

Increase surface area and create turbulence in incoming air to help warm, humidify, and filter the air.

How does the epiglottis function during breathing and swallowing?

Folds down to cover the laryngeal opening during swallowing and is open during breathing to allow air passage.

What happens during inspiration?

Diaphragm contracts, thoracic cavity volume increases, leading to lowered intra-alveolar pressure until air enters the lungs.

What is Boyle's Law relevant to respiratory physiology?

Pressure and volume are inversely related; as volume increases, pressure decreases, facilitating air movement.

How does hemoglobin transport oxygen in the blood?

Oxygen binds to iron in the heme groups of hemoglobin, primarily found in red blood cells.

What are the three ways carbon dioxide is transported in the blood?

Dissolved CO₂ in plasma, as carbaminohemoglobin attached to hemoglobin, and as bicarbonate ions (HCO₃⁻).

What are the effects of increased temperature on hemoglobin's affinity for oxygen?

Higher temperature decreases hemoglobin's affinity for oxygen, leading to more O₂ being released to tissues.

What occurs in altitude sickness?

Lower atmospheric pressure reduces O₂ partial pressure, resulting in less O₂ entering the blood, causing symptoms like headache and fatigue.

What is the difference between hyperpnea and hyperventilation?

Hyperpnea is appropriate increased breathing matching metabolic needs; hyperventilation is excessive breathing causing low CO₂ and increased blood pH.

What is the function of Type I alveolar cells?

Responsible for gas exchange in the alveoli.

What role does surfactant play in the lungs?

Reduces surface tension in the alveoli to prevent collapse.

Describe the process of internal respiration.

Gas exchange occurs between blood and body tissues, where O₂ moves from blood to tissues and CO₂ moves from tissues to blood.

What is external respiration?

Gas exchange between pulmonary capillary blood and alveoli, where O₂ enters blood and CO₂ is released into the alveoli.