Respiratory System Overview

Respiratory System Overview

• The respiratory system is responsible for breathing and gas exchange.
• Four key processes: ventilation (breathing), oxygen and carbon dioxide exchange between the lungs and blood, transport of these gases in the blood, and exchange of gases between blood and tissues.
• Other functions: regulation of blood pH, voice production, olfaction (sense of smell), and innate immunity.

Anatomy

• The respiratory system is divided into upper and lower respiratory tracts:
  • Upper respiratory tract: nose, pharynx, and larynx.
  • Lower respiratory tract: trachea, bronchi, and lungs.
• The nose consists of:
  • External nose: the visible part, mostly composed of hyaline cartilage.
  • Nasal cavity: extends from the nares (nostrils) to the choanae (openings into the pharynx).
  • Nares: external openings of the nose.
  • Choanae: openings into the pharynx.
  • Nasal septum: divides the nasal cavity into right and left sections.
  • Hard palate: floor of the nasal cavity, separating it from the oral cavity.
  • Conchae: bony ridges on each side of the nasal cavity that increase surface area, causing air to swirl and be cleansed, humidified, and warmed.
  • Paranasal sinuses: air-filled spaces in the skull that open into the nasal cavity. They resonate sound, reduce skull weight, produce mucus, and influence voice quality.
  • Nasolacrimal ducts: carry tears from the eyes and open into the nasal cavity.

Nose & Nasal Cavity Processes

• Air cleaning:
  • Coarse hairs in the nares trap large particles.
  • Mucus secreted by goblet cells traps smaller particles.
  • Cilia move the debris-laden mucus towards the pharynx, where it is swallowed.
• Air warming: blood vessels beneath the mucous epithelium warm the air.
• Air humidifying: moisture from the mucous epithelium humidifies the air.

Sneeze Reflex

• The sneeze reflex is a physiological response to foreign substances in the nasal cavity.
• Sensory receptors in the superior part of the nasal cavity detect foreign substances.
• These receptors initiate the sneeze reflex through action potentials.

Respiratory System Processes

• Ventilation or breathing is the movement of air into and out of the lungs.
• The exchange of oxygen (O2) and carbon dioxide (CO2) between the air in the lungs and the blood.
• The transport of O2 and CO2 in the blood.
• The exchange of O2 and CO2 between the blood and tissues.

Respiratory System Functions

• Regulation of blood pH.
• Voice production.
• Olfaction (sense of smell).
• Innate immunity.

Respiratory System Anatomy

• The respiratory system is divided into the upper respiratory tract (nose, pharynx, and larynx) and the lower respiratory tract (trachea, bronchi, and lungs).
• Nose: The external nose is the visible structure composed mainly of hyaline cartilage. The nasal cavity extends from the nares (nostrils) to the choanae (openings into the pharynx).
  • Nares/Nostrils: External openings of the nose.
  • Choanae: Openings into the pharynx.
  • Nasal Septum: Partition dividing the nasal cavity into right and left parts.
  • Hard Palate: Floor of the nasal cavity, separating it from the oral cavity.
  • Conchae: Bony ridges on each side of the nasal cavity, increasing the surface area of the nasal cavity and causing air to churn in order to be cleansed, humidified, and warmed.
  • Paranasal Sinuses: Air-filled spaces within bones that open into the nasal cavity. They function as resonating chambers, reduce the weight of the skull, produce mucus, and influence the quality of voice.
  • Nasolacrimal Ducts: Carry tears from the eyes and open into the nasal cavity.

Processes in the Nose & Nasal Cavity

• Coarse hairs inside the nares and mucus produced by goblet cells trap large particles.
• Cilia sweep the debris-laden mucus towards the pharynx, where it is swallowed.
• Air is warmed by blood vessels underlying the mucous epithelium and humidified by moisture.

Sneeze Reflex

• Foreign substances detected by sensory receptors in the superior part of the nasal cavity initiate an action potential.