Respiratory system

Nasal Cavity

Function/structure:

Warming and moistening Air – prevents epithelial damage​

• Large cavity that connects the external environment with the pharynx.  - This allows air from the external environment to be warmed and moistened​; Respiratory tissue is delicate so this prevents damage from microbes and air from dehydrating the epithelia

Physical first line of defense against pathogens/ debris​ - nose, explain how

• Hair and mucus trap dirt particles and microbes before they enter the lungs​

• Projections  (conchae) create turbulence in the air which helps the mucus trap dust and particles​

  • Each lateral wall of the nasal cavity has three bony projections called the superior, middle and inferior nasal conchae​

  • Nasal conchae increases the surface area of the nasal cavity to maximize warming and moistening of the air

EPITHELIUM IN THE RESPIRATORY SYSTEM - nasal cavity

• Pseudostratified ciliate columnar cells​

• Pseudostratified: looks like it has multiple layers but is one layer​

• Columnar: can specialize in secreting mucus​

• Ciliated: have small projections called cilia which move debris trapped in mucus out of the nose

THE PHARYNX​

Passage for food and air​​

THE PHARYNX​ - structure

3 sections

1. Nasopharynx​: Noso – closest to the nose​

2. Oropharynx​: Oro- (oral) closest to the mouth​

3. Laryngopharynx​: Laryngo – closest to the larynx

Epiglottis

flap of cartilage

Epiglottis - function

fits over the trachea when swallowing to prevent food from entering the trachea (and moving down into the lungs)

LARYNX​ - function and structure

STRUCTURE: Vocal cords supported by cartilage

FUNCTION: Sound production as air moves out of the lungs 

The bronchial tree

Trachea - function and structure

STRUCTURE: Tube from pharynx to bronchi – supported by C-shaped rings of cartilage

FUNCTION:

- Cartilage holds the trachea open for air movement​

- Ciliated epithelium along its length cleans the air with mucus 

Bronchi - function and structure

STRUCTURE:

-Division of the trachea into the right and left lungs​

–further divide into secondary and tertiary bronchi

FUNCTION - Air passage 

BRONCHIOLES ​ - function and structure

Structure

-very fine tubes with ​walls of smooth ​muscle​

-end in groups of​ air sacs (alveoli)

Function -air passage

Alveoli - function and structure

Structure:

• Occur in clusters and very thin moist walls​

• a large capillary network covers the sacs​

Function - Allow air to into very close contact with the blood so gas exchange can occur

Pleura - function and structure

STRUCTURE: Membrane covering the lung and the internal thoracic cavity ​

FUNCTION: Membrane produces pleural fluid which acts to reduce friction as the lung moves within the thoracic cavity 

Diaphragm - structure and function

STRUCTURE: Sheet of muscle which separates the thoracic cavity from the abdominal cavity​

FUNCTION:   Aids in the ventilation of the lung  

INTERCOSTAL MUSCLES​

STRUCTURE: Muscles found between the ribs 

FUNCTION: Aids in the movement of the ribs for the ventilation of the lungs