topic 18: The anatomy of the trachea...ETC

Question 1

anatomy of trachea

Answer 1

The trachea, or windpipe, is a vital structure in the respiratory system that connects the larynx to the bronchi, allowing air passage to the lungs.

-Location and Extent:
The trachea extends from the cricoid cartilage of the larynx (C6 level) to the carina (T4-T5 level), where it bifurcates into the right and left main bronchi.

-Structure:
Length: Approximately 10-12 cm in adults.

Diameter: About 2 cm.

Cartilaginous Rings: Composed of 16-20 C-shaped hyaline cartilage rings, which provide structural support and maintain the airway open.

Trachealis Muscle: A smooth muscle connecting the open ends of the cartilage rings posteriorly, allowing flexibility and adjusting the tracheal diameter during breathing.

Mucosa: Lined with pseudostratified ciliated columnar epithelium with goblet cells, which produce mucus to trap particles.

Question 2

Organization of the Bronchial System

Answer 2

starts with trachea that branches into progressive smaller airways

main/ 1° bronchi : left is larger & more horizontal while right is wider , shorter & more vertical

to
2°/lobular bronchi: 1 for each lobes so left side has 2 and right has 3

to
3°/segmental bronchi: for each bronchopulmonar segements so: left side- 5 and 5 / right side : 3,2,5

to
smaller bronchi
to
bronchioles; 3 types: conducting, respiratory and terminal brochioles.

from terminal bronchioles to alveolar ducts to alveoli where gasa exchange occurs

Question 3

histological properties of trachea & bronchi

Answer 3

Trachea:

Mucosa: Pseudostratified ciliated columnar epithelium with goblet cells.

Submucosa: Contains seromucous glands.

Cartilage: C-shaped hyaline cartilage rings but in bronchi it’s plates of the cartillage

Adventitia: Outer connective tissue layer.

Question 4

histological properties of bronchioles

Answer 4

Epithelium: Transition from pseudostratified ciliated columnar to simple ciliated columnar or cuboidal epithelium.

Goblet Cells: Decrease in number as bronchioles get smaller.

Clara (Club) Cells: Present in terminal and respiratory bronchioles; secrete surfactant-like substance.

Smooth Muscle: Prominent, allowing regulation of airway diameter.
Cartilage and Glands: Absent in bronchioles.

Question 5

Functional Structure of alveoli

Answer 5

Alveoli are the primary sites for gas exchange in the lungs, structured to maximize surface area and minimize the distance for diffusion.

Structure:

made of a thin epithelial layer, a basement membrane, and capillary endothelial cells.

and its Interalveolar Septa contains capillaries and elastic fibers, providing structural support and facilitating gas exchange.

Question 6

alveolar CELL TYPES

Answer 6

Type I Alveolar Cells (Pneumocytes):
Simple squamous epithelial cells.
Cover about 95% of the alveolar surface area.
Thin cells that facilitate gas exchange.

Type II Alveolar Cells (Pneumocytes):
Cuboidal cells.
Secrete pulmonary surfactant, reducing surface tension and preventing alveolar collapse.
Can proliferate and differentiate into Type I cells if necessary.

Alveolar Macrophages:
Found on the alveolar surface.
Phagocytose debris and pathogens, contributing to lung immunity.

Capillary Endothelial Cells:
Form the walls of the capillaries surrounding the alveoli.
Facilitate gas exchange between the blood and the alveolar air.