Respiratory System

Alveoli

Main site of gas exchange in the lungs.

Bronchioles

Small airways with smooth muscle that can bronchoconstrict or bronchodilate.

Bronchi

Carry air from the trachea to the bronchioles.

Diaphragm

Muscle that drives quiet breathing.

Epiglottis

Prevents food from entering the trachea.

Glottis

Opening between vocal cords that controls sound.

Larynx

Responsible for air passage and voice production.

Nasal cavity

Main function is to filter, warm, and humidify air.

Pharynx (respiratory function)

Moves air from the nasal cavity to the larynx.

Pleura

Double membrane that decreases friction and keeps lungs expanded.

Trachea

Carries air to bronchi; contains cartilage rings to prevent collapse.

Ventilation

Movement of air, consisting of inspiration and expiration.

Upper respiratory system

Includes nose, nasal cavity, sinuses, pharynx, and top half of larynx.

Lower respiratory system

Includes larynx (below vocal cords), trachea, bronchi, bronchioles, lungs, and alveoli.

Nasal conchae

Creates turbulent airflow in the nose.

Regions of the pharynx

Nasopharynx, oropharynx, and laryngopharynx.

Thyroid cartilage

Largest cartilage of the larynx, also known as the Adam’s apple.

Cricoid cartilage

Cartilage located below the thyroid cartilage.

True vs false vocal cords

True vocal cords produce sound; false vocal cords provide protection.

Right lung

Lung that has 3 lobes.

Left lung

Lung that has 2 lobes and the cardiac notch.

Visceral pleura

Pleura that is on the lung.

Parietal pleura

Pleura that lines the thoracic cavity.

Boyle’s Law

Explains breathing mechanics, indicating that pressure is inversely proportional to volume.

Inhalation process

Diaphragm contracts, thoracic volume increases, pressure decreases, air flows in.

Exhalation process

Diaphragm relaxes, volume decreases, pressure increases, air flows out.

Active vs passive breathing phases

Inhalation is the active phase; resting exhalation is passive.

Accessory inhalation muscles

Sternocleidomastoid (SCM), external intercostals, and pectoralis minor.

Accessory exhalation muscles

Internal intercostals and abdominals.

Partial pressure

Pressure made by one gas in a mixture, such as PO₂ and PCO₂.

Oxygen diffusion direction

Diffuses from high PO₂ in alveoli to low PO₂ in blood and tissues.

Carbon dioxide diffusion direction

Diffuses from high PCO₂ in tissues to low PCO₂ in blood and alveoli.

Pulmonary arteries

Blood vessels that carry deoxygenated blood to the lungs.

Pulmonary veins

Blood vessels that return oxygenated blood to the heart.

Medulla oblongata & pons

Brain regions controlling breathing.

Phrenic nerve

Nerve that controls the diaphragm.

Surface tension in alveoli

Created by water/mucous from Type I alveolar cells.

Surfactant

Substance produced by Type II alveolar cells to reduce surface tension.

Respiratory distress in premature infants

Caused by low surfactant leading to alveolar collapse.

Carbon dioxide transport methods

1. Dissolved in plasma (7%), 2. Carbaminohemoglobin (23%), 3. Bicarbonate ion HCO₃⁻ (70%).

Carbonic anhydrase

Enzyme that forms carbonic acid.

CO₂ and pH relationship

Higher CO₂ results in higher H⁺ and lower pH (acidosis); lower CO₂ results in lower H⁺ and higher pH (alkalosis).

Respiratory acidosis cause

Caused by hypoventilation or CO₂ retention.

Respiratory alkalosis cause

Caused by hyperventilation or CO₂ loss.

Asthma symptoms

Characterized by bronchoconstriction, inflammation, and mucous production.

Influenza effects

Affects the upper and/or lower respiratory tract.

Pneumonia mechanism

Involves fluid in the alveoli leading to impaired gas exchange.

Tuberculosis cause and symptoms

Caused by Mycobacterium tuberculosis, symptoms include cough with blood, fever, and weight loss.

COPD diseases

Includes chronic bronchitis and emphysema.

Chronic bronchitis

Characterized by inflammation of bronchi and mucous production.

Emphysema

Condition where alveoli are destroyed leading to reduced gas exchange.

Spirometry function

Measures air volumes such as tidal volume (TV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and residual volume (RV).

Tidal volume (TV)

Volume of air exchanged during resting breathing.

Residual volume (RV)

Amount of air left in the lungs after a maximum exhale.

Inspiratory reserve volume (IRV)

Maximum additional air that can be inhaled.

Expiratory reserve volume (ERV)

Maximum additional air that can be exhaled.

Vital capacity

Total volume of air that can be exhaled after a maximum inhalation (TV + IRV + ERV).

Total lung capacity

Total volume of air in the lungs (Vital capacity + RV).