Respiratory System Anatomy

Respiratory System Functions

• The three main functions are air conduction, air filtration, and gas exchange (respiration).

Pharynx Parts

• The nasopharynx connects to the nasal cavity; it contains eustachian tubes linking to the middle ear.
• The oropharynx connects behind the oral cavity.
• The laryngopharynx connects to the larynx.

Palates

• The hard palate is the rigid part separating the nasal cavity from the oral cavity.
• The soft palate is a continuation of the hard palate.

Trachea Rings

• Tracheal cartilaginous rings are "C" shaped and do not fully encircle the trachea.

Anterior Lung Landmarks

• Label A: Larynx
• Label B: Cartilaginous rings of trachea
• Label C: Bronchi
• Label D: Bronchioles
• Label E: Left Lung

Posterior Larynx Landmarks

• Label A: Epiglottis
• Label B: Thyroid cartilage
• Label C: Larynx
• Label D: Vocal Folds (true vocal cords)
• Label E: Cricoid cartilage
• Label F: Trachea
• Label G: Cartilaginous rings of trachea

Swallowing to Prevent Aspiration

• The larynx elevates.
• The trachea closes via the epiglottis moving inferiorly to cover it.

Soft Palate Elevation

• The soft palate elevates during swallowing to prevent food/liquid from entering the nasal passages.

Glottis definition

• The glottis is an opening into the larynx/voice box.

Aspiration Definition

• Aspiration occurs when food/liquid accidentally enters the trachea and then the lungs.

Lung Lobes

• The left lung has two lobes.
• The right lung has three lobes.

Pleura Functions

• The pleura reduces friction.
• The pleura provides a negative pressure environment.
• The pleura aids in pulling the lungs open during inhalation.

Respiratory Histology

• Pseudostratified ciliated columnar cells form the major histological structure in the respiratory system.
• The basement membrane serves as the "floor" of the epithelium in the respiratory tract.

Columnar Cells

• Respiratory epithelium cells are named columnar due to their rectangular shape.

Goblet Cells definition

• Goblet cells are wine-glass shaped mucous-producing cells.

Stratified Squamous Epithelium Location

• Stratified squamous epithelium's found in the vestibule of the nose.

Surfactant Purpose

• Surfactant covers the luminal surface of alveoli and prevents them from collapsing during exhalation.

Alveolar Epithelium Cell Types

• Type I alveolar cells make up most of the alveoli forming a thin, simple squamous layer, constituting 95% of alveolar epithelium.
• Type II alveolar cells comprise 5% of alveoli, dividing to replace damaged Type I cells and producing surfactant.

Abundant Alveoli Cell

• Alveolar macrophages are the most abundant cells within the alveoli.

Inhalation Steps

• Air moves into the lungs using negative pressure created by the pleural space.
• The rib cage lifts superiorly and anteriorly.
• The diaphragm flattens as it contracts.
• The thoracic cavity expands, increasing lung volume.
• The density of gases filling the lungs decreases.

Negative Pressure Definition

• Negative pressure inside the lungs means the pressure inside is less than the pressure outside.

Exhalation

• Exhalation is not an active process.

Hemoglobin Function

• Hemoglobin binds to oxygen in the blood for transport from the lungs to body tissues.

Respiration Muscle

• The diaphragm is largely responsible for providing movement for respiration.

ultimate Gas Exchange

• Gas exchange primarily occurs in the respiratory bronchioles and pulmonary alveoli.

CO2 Transport

• Most carbon dioxide is transported in the blood as bicarbonate ion.

Boyle's Law

• Boyle's Law indicates an inverse relationship between pressure and volume of a gas.

Charles' Law

• Charles’ Law explains how warming air is beneficial to the respiratory system.

Expiratory Reserve Volume

• The expiratory reserve volume is air exhaled beyond normal exhalation (~1200mL).

Tidal Volume defined

• Tidal volume is the amount of air inhaled/exhaled during quiet breathing.

Cystic Fibrosis cause

• Cystic Fibrosis is a hereditary disease where epithelial cells produce thick mucus, leading to respiratory failure and other complications such as salty sweat, sinusitis, male and female reproductive issues, blocked pancreas ducts, and improper nutrient absorption.

Pulmonary Edema cause

• Pulmonary edema is the accumulation of fluid in the lungs.
• Pulmonary edema is caused by infection, cancers, or congestive heart failure.
• Pulmonary edema causes crackling sounds in the lungs.

Lung Diseases

• Emphysema damages the alveoli, leading to breathing difficulties and is often caused by smoking.
• Cystic fibrosis is a hereditary disease impacting the epithelial cells of the respiratory tract and leads to chronic respiratory infections due to thick mucus.
• Pulmonary edema results in fluid accumulation in the lungs due to infections, cancers, or heart disease and fluid makes a crackling sound when lungs are listened to.
• Pleurisy is the inflammation of the pleura that causes sharp chest pain, possibly caused by cancer or injury.

Lung Anatomy

• The right lung has 3 lobes.
• The left lung has 2 lobes for heart space.

Lung Functions

• Major functions are: air conduction, air filtration, gas exchange.

Right Lung hilum

• The hilum is where blood vessels enter.
• The hilum is where the trachea turns into bronchi entering the lungs.

Pleurae

• The visceral pleura covers the lungs directly.
• The parietal pleura is the outer layer, closer to the abdominal cavity.

Pleural Cavity

• The pleural cavity is the space between visceral and parietal pleura.
• The pleural cavity contains air and lubricating fluid.
• The pleural cavity can fill with fluid/pus in disease states.
• The pleural cavity helps to pull the lungs open during inhalation.

Respiratory Filtration

• Nostrils contain hairs, cilia, and goblet cells that produce mucus to trap bacteria.
• The trachea and bronchi are lined with cilia and goblet cells.

Airflow Steps

• Air enters the nose, gets filtered, moistened, and warmed by mucosa.
• Hair filters out dust.
• Seromucous glands secrete antimicrobial substances that trap and moisten air.
• Blood flowing through capillaries in the mucosa warms the air.
• Air flows towards the trachea.

Respiratory Conduction

• Nasal cavities contain a vestibule (bottom external portion) covered with stratified squamous epithelium and thick hairs for catching debris.
• Nasal conchae warm and humidify air via blood capillaries.
• The nasopharynx connects to the nasal cavity.
• The oropharynx connects behind the oral cavity.
• The laryngopharynx connects to the larynx.
• Eustachian tubes, part of the nasopharynx, connect to the middle ear.
• The hard palate separates the nasal cavity from the oral cavity.
• The soft palate is a continuation of the hard palate.

Shared Passages

• Air also enters through the oral cavity.
• Passages will cross in the pharynx.
• Air enters into the trachea.
• Food and water enter through esophagus.

Larynx Action

• The soft palate elevates and moves backward to cover the nasal cavity.
• As food/liquid enters the oral cavity, the larynx elevates to help the epiglottis move down and cover the trachea.
• Cough reflex starts if food enters the trachea.

Epiglottis Function

• The epiglottis directs food/fluid away from the trachea into esophagus.
• The epiglottis' stem is attached to the hyoid bone and the interior rim of the thyroid cartilage.
• The epiglottis moves freely.

Swallowing

• The larynx rises and the epiglottis folds down over the laryngeal opening
• Coughing occurs if particles get to the trachea.

Vocal Cords

• Singing occurs when air's pushed/moved over the vocal folds.

Thyroid Cartilage

• The thyroid cartilage portions protrude and are most prominent.
• The thyroid cartilage includes Adam's apple in males.

Larynx Cartilages

• Single larynx cartilages are the thyroid, epiglottis and cricoid.
• Paired larynx cartilages are the arytenoid and corniculate.

Trachea Features

• The trachea has "C" shaped cartilaginous rings that help hold it open.

Bronchial Tree Pathway

• Primary bronchi branch into the secondary bronchi then branch into tertiary bronchi and finally into Bronchioles.
• This increases the surface area for respiration.
• Terminal bronchiole is the smallest portion of the conduction portion.
• Respiratory bronchiole-transition zone.

Alveoli Gas Exchange

• Alveoli are where gases are exchanged, wedged between capillaries.

Histology Definition

• Histology is the study of cellular anatomy of tissues/organs viewed under a microscope.

Cilia Definition

• Cilia catches allergies and's called ciliated pseudostratified columnar epithelium.

Goblet Cells

• Goblet cells produce mucus and catch debris.

Lung Epithelium Types

• Pseudostratified columnar epithelium is typical.
• Stratified squamous epithelium's layered.
• Simple squamous epithelium's long, flat cells in one layer which gas passes easily.

Alveoli Cell System Types

• Type 1 alveolar cells form a thin simple squamous layer and make up 95% of the epithelium.
• Type 2 alveolar cells make up 5%, divide/replace damaged Type 1 cells, and produce surfactant.

Alveolar Macrophages

• Alveolar macrophages specialize in immune defense.
• Alveolar macrophages are the most abundant cell in the alveoli.
• Alveolar macrophages eliminate bacteria, viruses, and other particles.
• Alveolar macrophages digest bacteria and move towards the surface of the alveoli, up the bronchial tree/trachea, and are coughed or sneezed out.

Oxygen Supply

• Ventilation (breathing), external respiration (lungs), internal respiration (tissues) and aerobic cellular respiration.

Ventilation

• Inhalation and exhalation require a negative pressure environment.
• The diaphragm flattens, changes pressure for Outside air (760mmHg) to move from high pressure to low pressure air flow.
• Breathing out causes pressure to change (762mmHg) - process restarts.

External Respiration

• Gas exchange qualities: large, thin, and moist which helps protect from damage, and diffuses oxygen.
• Diffuses high carbon dioxide in the blood, moves towards alveolus, and diffuses oxygen into the blood.

Internal Respiration

• Internal respiration diffuses high oxygen in the blood, diffuses to the cells, and diffuses into the lungs.

Hemoglobin

• Hemoglobin assists natural diffusion, binds alternatively to oxygen and carbon dioxide, red blood cells filled with hemoglobins, bicarbonate ion dissolves the most CO2 in the blood.

Aerobic Respiration

• Aerobic respiration uses oxygen for ATP production inside cells and CO2 to creates waste that expires out of cells to lungs.

Respiratory Physiology

• Atmospheric pressure at sea level equals 760mmHg (mercury) which equals 1 atm.
• Boyle's law states: pressure of a given quantity of gas is inversely proportional to its volume, ex. (higher volume =lower pressure, and lower volume=higher pressure).
• Charles' Law: The volume of a given quantity of gas is directly proportional to its temperature, ex. (higher temperature=higher volume, and lower temperature=lower volume)
• Dalton's Law- Total pressure of a gas mixture amounts to the sum of the partial pressures (PP) of the individual gases, measured as Ptotal=PA+PB+PC

Spirometry

• Spirometry measures pulmonary ventilation mechanics using a device like a spirometer.
• Tidal Volume: records the amount of air inhaled/exhaled in breathing.
• Inspiratory Reserve Volume: Records any maximum amount of air inhaled.
• Expiratory reserve Volume: records the normal determined effort.
• Residual Volume: air remaining in the lung.
• Vital Capacity = Inspiratory reserve+Tidal Volume+Expiratory reserve
• Inspiratory Capacity = Tidal Volume+Inspiratory Reserve Volume
• Functional Residual Capacity is measured using Expiratory reserve volume+residual volume
• Total Lung Capacity = Inspiratory Reserve Volume+Tidal Volume+Expiratory Reserve Volume+residual Volume

Lung Pathology

• Pathology is studying classifying, describing disease.
• Emphysema causes damage alveoli, due to smoking, the inner walls alveoli become weak/rupture.
• Emphysema lessens total of gas exchange, makes breathing difficult for the patient.
• Cystic Fibrosis includes airway obstruction and bacterial issues with thick and blood mucus.
• Other symptoms include genetic disease, thick mucus, chronic failure, widening airways etc.

Pulmonary Edema

• Pulmonary Edema's the accumulation of fluid in the lungs which is caused infection by lung diseases and can cause sounds by air in the alveoli during breathing.
• Pleurisy occurs because of the inflammation pleura, space fills fluids.
• Pleurisy causes sharp chest pain that worsens breathing.