Which features are associated with the tracheal epithelium?

Which features are associated with the tracheal epithelium?

Epithelial Cells of Trachea and Bronchi The characteristic feature of the trachea is the relatively regular sequence of C-shaped plates of hyaline cartilage interconnected by annular ligaments. The gaps in the cartilages are bridged by trachealis muscle, which is composed of smooth muscle fibers.

What type of cells form the walls of the alveoli?

The wall of each alveolus, lined by thin flat cells (Type I cells) and containing numerous capillaries, is the site of gas exchange, which occurs by diffusion.

What are the cumulative divisions of the bronchi called?

Anatomy of the Bronchi The right main bronchus subdivides into three lobar bronchi, while the left main bronchus divides into two. The lobar bronchi (also called secondary bronchi) divide into tertiary bronchi, each of which supplies air to a different bronchopulmonary segment.

At which level does trachea divide to form primary bronchi?

fifth thoracic vertebra
In the mediastinum, at the level of the fifth thoracic vertebra, the trachea divides into the right and left primary bronchi. The bronchi branch into smaller and smaller passageways until they terminate in tiny air sacs called alveoli.

What is the first part of the trachea called?

The trachea begins just under the larynx (voice box) and runs down behind the breastbone (sternum). The trachea then divides into two smaller tubes called bronchi: one bronchus for each lung. The trachea is composed of about 20 rings of tough cartilage.

Why is the trachea ribbed?

C-shaped cartilaginous rings reinforces the anterior and lateral sides of the trachea to protect and maintain the airway open. (The cartilaginous rings are incomplete because this allows the trachea to collapse slightly to allow food to pass down the esophagus.)

What are the functions of the type 1 and 2 pneumocytes?

Pneumocyte: One of the cells lining the alveoli (the air sacs) in the lung. The alveoli are, in fact, lined with two types of cells termed the type 1 and type 2 pneumocytes: Type 1 pneumocyte: The cell responsible for the gas (oxygen and carbon dioxide) exchange that takes place in the alveoli.

Which bronchus is more horizontal?

The left primary bronchus is more horizontal than the right primary bronchus due to the position of the heart.

Which is bigger the right or left primary bronchus?

As the bronchi subdivide into smaller (subsegmental) bronchi, the amount of cartilage decreases, and the amount of smooth muscle increases. Left main bronchus: The left bronchus is smaller and longer than the right main bronchus (approximately 5 cm or 1.5 inches.)

How many alveolar sacs are in the bronchi?

The segmental bronchi divide into many primary bronchioles that divide into terminal bronchioles. Each terminal bronchiole then gives rise to several respiratory bronchioles, which go on to divide into two to 11 alveolar ducts. There are five or six alveolar sacs associated with each alveolar duct.

What makes a type I alveolar cell squamous?

Type I cells are thin and flat and form the structure of the alveoli. Type I alveolar cells are squamous (giving more surface area to each cell) and cover approximately 90–95% of the alveolar surface.

What are Type II cells in the alveolar wall secrete?

Type II cells in the alveolar wall contain secretory granular organelles known as lamellar bodies that fuse with the cell membranes and secrete pulmonary surfactant. This surfactant is a film of fatty substances (the majority of which are dipalmitoylphosphatidylcholine), a group of phospholipids that reduce alveolar surface tension.

Where does surfactant come from in the alveoli?

The surfactant is produced by the type II cells which are the most numerous cells in the alveoli, yet do not cover as much surface area as the squamous alveolar cells (a squamous epithelium). Type II cells also repair the endothelium of the alveolus when it becomes damaged.

How are alveoli and pulmonary surfactant work together?

It carries fresh oxygen from the lungs to the left side of the heart B. it dilates the bronchioles in the lungs and enhances the flow of air C. It lubricates the alveolar walls and allows them to expand and recoil D. It facilitates the transport of oxygen-poor blood from the right ventricle to the lungs.

Which is part of the trachea leads to the alveoli?

They lead to the alveoli by way of alveolar ducts. Together, the trachea and the two primary bronchi are referred to as the bronchial tree. At the end of the bronchial tree lie the alveolar ducts, the alveolar sacs, and the alveoli. The tubes that make up the bronchial tree perform the same function as the trachea: they distribute air to the lungs.

What causes the dilatation of the alveoli in the lungs?

This inability to expel air leads to further dilatation of the alveoli and the increased loss of function. Pneumonia is an infection that inflames the alveoli in one or both lungs and can result in the air sacs filling with pus. Tuberculosis is an infectious bacterial disease characterized by the growth of nodules in the tissues of the lungs.

How does the alveoli maintain the shape of the air sac?

Alveoli are lined by a fluid layer known as a surfactant which maintains the shape and surface tension of the air sac. By maintaining surface tension, there is more surface area through which oxygen and CO2 molecules can pass.