The Respiratory System

Flashcards covering the vocabulary of the respiratory system

Ventilation

The movement of air into the lungs (inspiration) and out of the lungs (expiration).

External respiration

Diffusion of gases between the alveolar air and the pulmonary blood.

Blood gas transport

Mechanisms used to transport O2 and CO2 through the bloodstream.

Internal respiration

Diffusion of gases between tissue capillaries and interstitial fluid.

Conducting passages

Carry air into and out of the body but are not involved in gas exchange; include the nose, pharynx, trachea, larynx, bronchi, bronchioles and terminal bronchioles

Respiratory passages

Are used for gas exchange with the blood; include the respiratory bronchioles, alveoli and alveolar ducts.

Trachea Location

Extends from the inferior larynx (C6) and to the carina (sternal angle (T4 -T5 (adults)) where it divides to form the primary bronchi.

Trachea Functions

Forms a patent airway, ciliated epithelium filters the inspired air, and the lowest tracheal ring (carina) has sensory receptors that initiate cough reflexes.

Bronchial tree

Consists of the primary bronchi and their subdivisions.

Alveoli

Walls are primarily made of simple squamous epithelium called type I cells; cuboidal cells called type II cells secrete surfactant; macrophages (dust cells) are present; clusters of alveoli are called alveolar sacs; adjacent alveoli are connected by alveolar pores

Apex

Conical, superior tip of each lung.

Base

Concave, inferior surface of each lung; rests on the diaphragm.

Hilus

Indentation on the mediastinal surface that receives blood vessels and bronchi.

Mediastinal surface

Borders the mediastinum.

Costal surface

Posterior, lateral and anterior surfaces in contact with the ribs.

Diaphragmatic surface

Inferior surface in contact with the diaphragm.

Visceral pleura

Adheres to the surface of the lung.

Parietal pleura

Lines the thoracic cavity and the thoracic surface of the diaphragm.

Pleural cavity

Contains a small amount of pleural fluid.

Respiratory membrane structure

Alveolar endothelium, basal lamina, and capillary endothelium.

Boyle’s Law

Gas pressure is inversely related to the space (volume) that it occupies.

Dalton’s Law of Partial Pressures

The total pressure exerted by a mixture of gases is the sum of the pressures exerted individually by each of the gases in the mixture.

Henry’s Law

When a mixture of gas comes into contact with a liquid, a gas will dissolve into the liquid in proportion to its partial pressure and will diffuse until equilibrium is achieved.

External Respiration

The diffusion of gases between the alveolar air and the blood in the pulmonary capillaries across the respiratory membrane.

Internal Respiration

The diffusion of gases between the blood of tissue capillaries and interstitial fluid.

Haldane Effect

Reduced Hb has a greater capacity to bind CO2 than HbO2 does.

Ventral Respiratory Group location and function

Ventral medulla; extends from the pons to the spinal cord; this sets the basic ventilation rate - contains inspiratory neurons and expiratory neurons.

Dorsal Respiratory Group location and function

Dorsal medulla, near the root of cranial nerve IX; Integrates impulses from peripheral stretch receptors and chemoreceptors and relays them to the ventral respiratory group.

Pontine Respiratory Center

Modifies the basic rhythm in concert with vocalization, sleep, exercise and other activities.

Apneustic Center

Assists in the transition between inspiration and expiration.

Inflation Reflex (Hering Breuer Reflex)

Lung inflation activates stretch receptors in the visceral pleura and in the conducting portions of the bronchial tree.

pCO2 and peripheral chemoreceptors impact on ventilation rate

Increased pCO2 leads to hyperventilation; decreased pCO2 leads to hypoventilation.

Hypercapnia

Is increased arterial pCO2.

Hypocapnia

Is decreased arterial pCO2.

pO2 and peripheral chemoreceptors impact on ventilation rate

If pO2 falls below 60 mmHg, hyperventilation occurs; ventilation rate is less sensitive to pO2 than pCO2.

Arterial pH impact on ventilation rate

Decreases in arterial pH lead to hyperventilation, and increases in arterial pH lead to hypoventilation, even if the pO2 and pCO2 are normal.

Eupnea

Normal quiet breathing.

Apnea

Cessation of breathing.

Hyperpnea

Deep, vigorous breathing.

Dyspnea

Difficult, labored breathing.

Tachypnea

Rapid breathing.

Emphysema Characteristics

Permanent enlargement of respiratory bronchioles, alveolar ducts and alveoli; destruction of alveolar walls; loss of elasticity.

Asthma Characteristics

Chronic airway inflammation and hyperresponsive tracheobronchial tree.

Tuberculosis Characteristics

Reactivation or reinfection produces respiratory symptoms: chest pain, bloody sputum, granulomas and lung cavitation.

Bronchogenic Carcinoma Characteristics

Cough, weight loss, chest pain and dyspnea; increased sputum production; tumor obstruction of airways; frequent metastasis.

Cystic Fibrosis Characteristics

Mucus accumulation leads to chronic cough, persistent lung infections, obstructive pulmonary disease; digestive tract and reproductive tract also involved; malabsorption of nutrients, fat soluble vitamin deficiencies.