Respiratory System Flashcards
What are the functions of the respiratory system?
Conduction of inspired air
Pulmonary Ventilation (gas exchange)
What are the respiratory system organs?
Nose, nasal cavity, and paranasal sinuses
Pharynx, larynx, and trachea
Bronchi and their smaller branches
Lungs and alveoli
Components of the respiratory system?
Nasal cavity + paranasal sinuses
Pharynx
Larynx
Trachea
Conducting Zone
Primary bronchi
Lobar bronchi
Segmental bronchi
The Nose
Airway for respiration
Filtration of inhaled air
Moistening and warming of the air
Resonating chamber for speech
The site of olfactory receptors (smell is accomplished only through the nasal cavity)
Paranasal Sinuses
Can be a resonating chamber for speech
Lightens the weight of the skull
Can fill with fluid (negative function)
Pharynx and its 3 subdivisions
A passageway connecting the nasal and oral cavities superiorly to the larynx and esophagus inferiorly, divided into three parts:
Nasopharynx
Oropharynx
Laryngopharynx
Larynx Structure
Framework of 9 cartilages connected by ligaments and membranes
Suspended from the hyoid bone
Enclosed laterally by the pharynx
Inferiorly continuous with the trachea
Larynx Function
Voice production (voice box)
Open airway
Mechanism of directing air and food into their proper channels- the trachea and esophagus
Trachea (windpipe)
Descends from the larynx through the neck into the mediastinum, where it ends by dividing into the two primary bronchi
Structure of the Bronchial Tree
Main Bronchi (Primary)
Lobar Bronchi (secondary)
Segmental Bronchi (tertiary)
Bronchioles
Main Bronchi (primary)
Largest subdivisions, enter the lungs
Lobar Bronchi (secondary)
3 on the right side (right lung)
2 on the left side (left lung)
Segmental Bronchi (tertiary)
Branch into each lung segment (bronchopulmonary segment)
Bronchioles
Small bronchi, less than 1mm in diameter
Aspiration of Foreign Bodies
Since the right bronchus is wider, shorter, and runs more vertically; foreign bodies are more likely to enter and stay on the right bronchus or its branches
Respiratory Zone
The terminal part of the respiratory tree in the lungs where gas exchange takes place
Gas exchange occurs in the alveoli (air sacs at the end of respiratory tree)
Pleura
A double-layered sac surrounding each lung
Parietal Pleura
Lines the pleural cavity
Visceral Pleura
Covers the lung
Pleaural Cavity
Potential space between the visceral and parietal layers of pleura
Lung Features
Right lung: 3 lobes; oblique and horizontal fissures
Left lung: 2 lobes; oblique fissure; cardiac notch
Pulmonary Ventilation (breathing)
Compromised of 2 Phases:
Inspiration
Expiration
Inspiration
The period when air flows into the lungs:
- The diaphragm contracts, moving inferiorly. This increases the volume of the thoracic cavity
- The external intercostal muscles contract to raise the ribs. This results in an enlargement of both the lateral dimension and the anterior/posterior dimension of the thorax
- The intercostal muscles also function to stiffen the thoracic wall. If the wall is not stiffened, the thorax would just change shape, and not necessarily increase its volume
Expiration
The period when gases exit the lungs:
- quiet: relaxation of external intercostals + diaphragm; decreases thoracic volume; increase lung pressure- outflow of air
- forced: involves internal intercostals and abdominal muscles
Ventilation
Conceive of the thorax as an expandable container with only one entrance, the trachea
- Enlarging the dimensions of the thorax decreases air pressure within it. This causes air to flow in from the outside. Air always moves from high to low pressure
- During normal inspiration, the diaphragm and intercostal muscles function to increase the volume of the thorax
Increases in Thoracic Volume
Vertical dimension (height): diaphragm contracts and descends
Anteroposterior (AP) dimension: increases considerably when the intercostals contract (pump-handle movement)
Transverse Dimension: slight increase with bucket-handle movement
Changes in the Thoracic Volume during Inspiration
- As the ribs are raised by the contracting external intercostal muscles, the anteroposterior dimension of the thorax also enlarges
- The external muscles elevate the ribs during inspiration, causing the thorax to expand laterally
Diaphragm
- Skeletal Muscle
- Receives somatic motor and sensory innervation from phrenic nerves (C3-C5) centrally and intercostal nerves peripherally (sensory innervation)
- Blood supply: From the musculophrenic and pericardiacophrenic arteries (branches of the internal thoracic artery)
