lecture 20 - respiratory system

what is a tracheotomy? why is it performed and based on what conditions?

a medical procedure where the trachea is incised or cut open. this is performed when a patient requires extended breathing assistance based on:

• the presence of an upper airway obstruction due to a foreign body, trauma, swelling, etc

• difficulty breathing due to advanced pneumonia, emphysema, or severe chest wall injury

• respiratory paralysis

what is a cricothyrotomy? when is it typically performed and who usually does it?

a procedure where an incision is made through the skin and cricothyroid membrane for immediate relief of airway obstruction. often performed by EMTs and paramedics to open the airway quickly when the patient cannot breathe on their own.

what is a pneumothorax?

a condition that occurs when free air gets into the pleural cavity

what is a hemothorax?

when blood collects in the pleural space due to a lacerated artery, a blood vessel that leaks bc of surgery, heart failure, or certain tumors

what is pneumonia?

an infection of the alveoli of the lung commonly caused by viruses, bacteria, and sometimes fungi

what is sputum?

mucus and other matter that are produced and expelled by the bronchi during infection

define respiration and its purpose

gas exchange of oxygen and carbon dioxide between the atmosphere and body cells

what are the main anatomical areas of the respiratory system? (head, neck, trunk, lungs) (11)

nose, nasal cavity, pharynx, larynx, trachea, bronchus, bronchiole, terminal bronchiole, respiratory bronchiole, alveolar duct, alveoli

what is the difference between the conducting and respiratory portions of the respiratory system? where does gas exchange occur?

the conducting portion conducts and transfers air while the respiratory portion exchanges gas with blood

describe the main functions of the respiratory system

warms, humidifies, and filters inspired air

how does the respiratory system warm and humidify air?

the gases are warmed to body temp by being in close contact with the nasal blood vessels transporting warm blood and the gases are then humidified through contact with the pseudostratified ciliated columnar epithelium and its sticky mucous

explain how the entrance to the respiratory system helps to filter the air

since the entrance is inferiorly oriented, it prevents large particles, microorganisms, and insects from entering

where is the olfactory epithelium located and what is its function?

located in the upper portion of the nasal cavity and is responsible for smell

what are the functions of the nostrils?

nostrils are responsible for air filtration, conditioning, olfaction, and resonance of sound

what structures form the floor of the nasal cavity?

the hard and soft palates

describe the location and function of the nasal conchae

located on lateral sides of nasal cavity

consists of the superior, middle, and inferior nasal conchae

functions: filtration of air, conditioning of air, olfaction, and resonance of sound

what are the paranasal sinuses and where are they located?

paired cavities/spaces that connect to the nasal cavity (maxillary, ethmoid, sphenoid, and frontal)

explain the functions of the sinuses

cleanse (warm and humidify) air and sound resonance chambers

describe the pharynx and its connections to other parts of the respiratory and digestive systems

the pharynx (nasopharynx, oropharynx, and laryngopharynx) connects the nasal cavity and mouth to the larynx and esophagus

what role do the tonsils play in the pharynx?

they protect the pharynx from infection

what are the functions of the larynx?

prevents food/drink from entering the trachea, conducts air, produces sound

name the cartilages found in the larynx and their roles

thyroid cartilage, cricoid cartilage, epiglottis, and arytenoid cartilage

responsible for structure, airway protection and voice production

describe the structure and function of vocal folds

left and right vocal folds (true vocal chords) attach from arytenoid to thyroid cartilage and is responsible for the production of sound

how is sound produced?

when cords vibrate against pressure of air → air being forced through larynx → sound

describe the trachea’s structure and its role in conducting air

connects to the larynx superiorly and travels into the mediastinum which then splits into left and right bronchi

comprised of the conducting and respiratory portions

what are the conducting and respiratory portions comprised of?

conducting = trachea, bronchi, bronchioles, and terminal bronchioles

respiratory = respiratory bronchioles, alveolar ducts, alveoli

how does the bronchial tree change as it branches further into the lungs?

splits into the primary bronchi → secondary (lobar) → tertiary (segmental) → smaller bronchi

differentiate between primary, secondary, and tertiary bronchi regarding location and function

primary = enters the hilum of each lung together with the pulmonary vessels, lymphatic vessels, and nerves

secondary = supplies a single lobe of a lung (2 for left and 3 for right)

tertiary = supplies bronchopulmonary segment

what are the bronchioles and how they differ from bronchi?

bronchioles are smaller conducting airways of bronchial tree with no cartilage and proportionately greater amounts of smooth muscle in walls.

bronchi are the largest airways of bronchial tree with incomplete rings and irregular plates of cartilage and some smooth muscle.

where does gas exchange occur and why are alveoli suited for this function?

the thin walls of the alveoli are specialized to promote diffusion of gases between the alveolus and the blood in the pulmonary capillaries

explain the structure of the respiratory membrane

simple squamous epithelium of alveolus

simple squamous epithelium of a pulmonary capillary

list the lobes of the right and left lungs

right lung = superior, middle, and inferior lobes

left lung = superior and inferior lobes

describe the pleura and pleural cavity

parietal pleura = lines internal thoracic walls

visceral pleura = lines outer surface of lungs

pleural cavity = between parietal and visceral layers and produces serous fluid

what is the purpose of the pleura and pleural cavity?

allows frictionless lung movement during breathing, cushion the lungs, and maintain negative pressure to keep the lungs expanded and connected to the chest wall

describe the muscles involved in quiet breathing

diaphragm and external intercostals (muscles of quiet breathing = relaxed inspiration)

describe the muscles involved in forced inspiration/expiration

forced inspiration = deep inspiration

• sternocleidomastoid

• pectoralis minor

• serratus posterior superior

describe the muscles involved in forced expiration

forced expiration

• internal intercostals

• abdominal muscles

• serratus posterior inferior

how does the respiratory system use pressure changes to facilitate breathing?

boyle’s law = the pressure of a gas decreases if the volume of the container increases and vice versa

air flows from a region of higher pressure (the atmosphere) into a region of lower pressure within the lungs (the intrapulmonary region) and vice versa

list the order of air flow (13 structures)

1. nose and nasal cavity

2. nasopharynx

3. oropharynx

4. laryngopharynx

5. larynx

6. trachea

7. primary bronchus

8. secondary bronchus

9. tertiary bronchus

10. terminal bronchiole

11. respiratory bronchiole

12. alveolar duct

13. alveolus