Ch. 22 - The Respiratory System

22.1 Anatomy of the Respiratory System

Variable affecting the efficiency of gas exchange in the alveolus - will be asked abt on the quiz

Oxyhemoglobin disassociation curve - may be questions on quiz

Overview

• Respiration

  • can mean ventilation of the lungs (breathing) OR

  • use of oxygen in cellular metabolism

• Functions of the respiratory system

  • Gas exchange: provides oxygen & CO2 exchange btw blood & air

  • Communication: serves for speech and other vocalization

  • Olfaction: sense of smell

  • Acid-Base balance: controls pH of the body fluid

  • Blood Pressure Regulation: help synthesize angiotensin II, a hormone that regulate BP

  • Platelet Production: half the blood platelets is made by megakaryocytes in the lungs

  • Blood and Lymph Flow: promote flow of lymph and venous blood bc breathing creates pressure gradients btw thorax & abdomen

  • Blood Filtration: filter small blood clots - preventing obstruction

  • Expulsion of abdominal contents: breath-holding & abdominal contraction help to expel abdominal contents during urination, defecation, & childbirth

• Air flows along a dead-end pathway consisting essentially of bronchi → bronchioles → alveoli

• Conducting zone: consisting of passage that serve only for airflow, essentially from nostrils through the major bronchioles

• Respiratory Zone: consists of the alveoli and other gas-exchange regions of the distal airway

• The Upper Respiratory Tract: nose through the larynx

• The Lower Respiratory Tract: Trachea through the lungs

The Nose

• Several functions: Warms, cleanses & humidifies inhaled air, detects oder, and serves as a resonating chamber that amplifies the voice

• Nostrils or Nares: anterior openings

• Posterior Nasal Apertures or choanae: posterior openings

• Facial part of the nose is shaped by bone & Hyaline cartilage

  • Superior half is supported by a pair small nasal bones medially and the maxillae laterally.

  • The inferior half is supported by the lateral and alar cartilages

  • The flared portion on each side of the lower end of the nose called the ala nasi, shaped by the alar cartilages and dense connective tissue

• Nasal Cavity - internal chamber of the nose

  • divides into right and left halves = nasal fossae

  • The dividing wall is a vertical plate called the nasal septum, which is composed of bone and hyaline cartilage

    • Vomer forms one-thrid

    • The perpendicular plate of the ethmoid forms the superior two thirds

    • Septal cartilage forms the non bony anterior part of the septum

  • Both the ethmoid & sphenoid compose the roof of the nasal cavity

  • paranasal sinuses and the nasolacrimal ducts of the orbit drain into the nasal cavity

  • Nasal cavity begins with a small dilated chamber called the vestibule just inside the nostril, bordered by the ala nasi

    • lined with stratified squamous epithelium, guard hairs, or vibrissae

  • Posterior to the vestibule, contained by three folds of tissue - the superior, middle, & inferior nasal conchae OR turbinates which project from the lateral walls toward the septum

    • Beneath each conchae are narrow air passages called a meatus

      • captures dust and air picks up moisture and heat from the mucosa - enables the the nose to cleanse, warm, & humidify the air more effectively

• The Mucosa