Respiratory System Overview

Respiratory System Overview

• The respiratory system is composed of upper and lower parts
• Upper respiratory part includes the nose, nasal cavity, laryngopharynx, and larynx
• Lower respiratory part includes the trachea, bronchi, bronchial tree, and lungs

The Nose

• The nose consists of the external nose and nasal cavity
• The nasal cavity is divided by a septum into right and left halves
• The external nose has two nostrils
• The lateral margin (ala nasi) is rounded and mobile

Nasal Cavity

• The nasal cavity extends from the nostrils to the posterior nasal apertures (choanae)
• The nose opens into the nasopharynx

Regions of the Nasal Cavity

• Vestibule
• Olfactory region
• Respiratory region
• Nasopharynx
• Auditory tube opening

Paranasal Sinuses

• Air cavities in the skull bones around the nose
• Open into the nasal cavity's lateral wall
• Include frontal, ethmoidal, sphenoidal, and maxillary air sinuses
• Functions: humidifying and warming inspired air, regulating intranasal pressure, increasing surface area for olfaction, lightening the skull, resonance, absorption shock, and contributing to facial growth

Clinical Notes (Nasal Cavity)

• Epistaxis (nosebleed)
• Rhinorrhea (runny nose)
• Rhinitis (inflammation of the nasal mucosa)

Little's (Kiesselbach's) Area

• Area of the nasal septum susceptible to bleeding
• Supplied by anterior and posterior ethmoidal arteries, sphenopalatine artery, and superior labial artery (septal branch)

The Pharynx

• A muscular tube (12-13 cm long)
• Lies behind the oral, nasal, and laryngeal cavities
• Extends from the skull base to the lower border of the cricoid cartilage (at the level of the 6th cervical vertebra)
  • Continuing with the esophagus

Parts of the Pharynx

• Nasopharynx (upper part)
  • Lies behind the nasal cavity
  • Auditory tube openings in the lateral wall
• Oropharynx (middle part)
  • Located behind the oral cavity
• Laryngopharynx (hypopharynx)
  • From the hyoid bone to the cricoid cartilage
  • Continuous with the esophagus

Larynx

• Phonation box and air passage
• Located in the middle anterior part of the neck
• Cartilages, membranes, and muscles

Cavity of Larynx

• Extends from the larynx inlet to the trachea's beginning
• Contains (in the central, middle part of the cavity): two pairs of vocal folds (or cords)

Trachea

• Begins at the laryngeal outlet and ends at the sternal angle
• Divides into the right and left bronchi (carina bifurcation)
• 10 cm long, fibromuscular wall, C-shaped hyaline cartilages

Bronchi and Bronchial Tree

• Right and left principle bronchi start at the sternal angle
• Branches leading to tertiary bronchi (bronchopulmonary segments)

Lung

• Paired organs in the thoracic cavity
• Covered by pleura and protected by the thoracic skeleton
• Each lung has: apex, broad base (inferior surface), sharp anterior and inferior borders
• Sternoclavicular, diaphragmatic, and mediastinal surfaces
• Right lung: wider and shorter, 3 lobes, 2 fissures (oblique and horizontal)
• Left lung: narrower and longer, 2 lobes, 1 oblique fissure

Surfaces of the Lung

• Costal surface: large, smooth, convex, related to the costal pleura, ribs, costal cartilages, and inner intercostal muscles
• Mediastinal surface: concave, related to the middle mediastinum (pericardium and heart), includes the hilum (root of the lung)
• Diaphragmatic surface: concave, forms the lung base, resting on the diaphragm dome.

The Hilum of the Lung

• Wedge-shaped area on the lung's mediastinal surface
• Structures of the lung root pass through

Differences between Right and Left Lungs

• Right lung: 3 lobes, straighter anterior border, larger, heavier (about 700g), shorter, broader
• Left lung: 2 lobes, anterior border interrupted by the cardiac notch, smaller, lighter (about 600g), longer, narrower

Pleura

• Serous sac investing the lungs
• Outer parietal and inner visceral layers separated by a pleural cavity

Physiology of Breathing

• Breathing in: chest expands, diaphragm contracts
• Breathing out: chest contracts, diaphragm relaxes

Clinical Notes (Lungs)

• Pleuritis (inflammation of the pleura)
• Pneumothorax (air in the pleural cavity)
• Hemothorax (blood in the pleural cavity)

Radio-Anatomy of the Lung

• Diagram showing features visible in a chest X-ray
• Shows elements of the lung like the aortic arch, main bronchi, and fissures

Diaphragm

• Musculotendinous structure with two parts
• Muscular part: fixed
• Central part: movable (fibers radiating, forming central tendon)
• No bony attachments

Openings of the Diaphragm

• Aortic hiatus (T12) for aorta
• Esophageal hiatus (T10) for esophagus
• Caval opening (T8) for inferior vena cava (IVC)

Intercostal Muscles

• External, internal, and innermost intercostal muscles
• Include intercostalis, subcostalis, sterncostalis (transversus thoracis)

This quiz covers the components and functions of the respiratory system, focusing on the upper and lower respiratory tracts. It includes details about the structure of the nose and the nasal cavity, as well as the associated paranasal sinuses. Test your knowledge about how these parts work together to facilitate breathing.