The alveoli are responsible for the spongy nature of the lung. These alveoli are lined by flattened epithelial cells called pneumocytes with a single opening. The alveolar wall or septum is made up of three tissue components:
surface epithelium, supporting tissue, and an extensive network of continuous capillaries
.
What are the 3 cell types found in the alveoli?
- Type 1 pneumocytes.
- Type 2 pneumocytes.
- Alveolar macrophages.
What is the epithelium of the alveoli?
The majority of the respiratory tree, from the nasal cavity to the bronchi, is lined by pseudostratified columnar ciliated epithelium. The bronchioles are lined by simple columnar to the cuboidal epithelium, and the alveoli possess a lining of
thin squamous epithelium
that allows for gas exchange.
What tissue are alveoli made of?
Alveoli are therefore made up of a
thin layer of epithelial cells
that are in direct contact with endothelial cells in the capillaries.
What is the histology of trachea?
The trachea is constituted mainly by
incomplete cartilage rings lined by
a res- piratory epithelium (ciliated and mucous cells) with variable morphology according to the region observed. … This organ is constituted mainly by longitudinal septa formed by connective tissue, smooth muscle cells and blood capillaries.
What are the two types of alveoli?
The alveolar epithelium comprises two main cell types:
the alveolar type I and alveolar type II cell
. The type I cell is a complex branched cell with multiple cytoplasmic plates that are greatly attenuated and relatively devoid of organelles; these plates represent the gas exchange surface in the alveolus.
What is the function alveoli?
The alveoli are where
the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out
. Oxygen breathed in from the air passes through the alveoli and into the blood and travels to the tissues throughout the body.
How many alveoli are there?
At the end of each bronchiole is a special area that leads into clumps of teeny tiny air sacs called alveoli (say: al-VEE-oh-lie). There are
about 600 million alveoli
in your lungs and if you stretched them out, they would cover an entire tennis court.
Where is alveoli found in the body?
The alveoli are located in
the alveolar sacs of the lungs in the pulmonary lobules of the respiratory zone
. They are more numerous in the blind-ended alveolar sacs. Respiratory bronchioles lead into alveolar ducts which are deeply lined with alveoli.
How alveoli are kept dry?
Except for a thin film of moisture on the alveolar wall, the alveoli are kept dry by
the absorption of excess liquid by the blood capillaries
(dependent on hydrostatic and oncotic forces described by the Starling equation).
Are alveoli one cell thick?
a) The alveoli wall (and the capillary wall) is
only one cell thick
so there is only a short distance over which diffusion takes place (short diffusion pathway) so there is a faster rate of diffusion of oxygen from alveoli into the blood.
What shape are alveoli?
Each alveolus is
cup-shaped with very thin walls
. It’s surrounded by networks of blood vessels called capillaries that also have thin walls. The oxygen you breathe in diffuses through the alveoli and the capillaries into the blood.
Are the alveoli organs?
This tissue consists of more than 40 cell types, originating from all three germ layers, and a sophisticated connective tissue network. Together they form an organ with a complex architecture optimized to serve its main function. Gas exchange takes place in lung alveoli.
What is the histology of the stomach?
The stomach is divided into 4 anatomical regions: the
cardia, fundus, body, and pylorus
. But the stomach is only divided into 3 histological regions: the cardia, fundus, and pylorus. That’s because the fundus and body are histologically identical, so both regions are called the fundus when referring to their histology.
Why is the trachea pseudostratified?
The presence of pseudostratified columnar epithelium in the upper respiratory tract (composed of the nose, trachea and bronchi)
protects the lungs from these irritants
. Goblet cells of the epithelium secrete mucus to trap particles and prevent them from traveling further down respiratory passages.
Does the trachea have cartilage?
A normal trachea (windpipe)
has many rings made of cartilage
(a strong and flexible tissue). These rings are C-shaped and support the trachea but also allow it to move and flex when your child breathes.
