2- Pharynx
‫المحاضر‬
‫ة الثالثة‬
The pharynx is the part of the digestive system of
many animals immediately behind the mouth and
in front of the esophagus
The human pharynx is divided into three sections:
1. the nasopharynx
2. the oropharynx
3. the laryngopharynx
3- The Larynx
Because of its location, the larynx has three
important functions:
1- Control of the airflow during breathing.
2- Protection of the airway.
3- Production of sound for speech.
4- Epiglottis
The epiglottis is the flap of cartilage lying behind the
Tongue and in front of the entrance to the larynx .
5- The uvula
Is a fleshy piece of muscle, tissue and mucous membrane
that hangs down from the palate.
It is the part that moves upward when we say, "Ah!".
6- The Trachea
It is a tube 2 cm diameter and 10 cm in long.
It is kept open by incomplete rings of cartilage the
deficiency onthe posterior surface being filled in with
fibrous and mascular tissue.
The wall of trachea consists of:
1- Mucosa: it is formed of
(A) Epithelium
(B) Corium (Lamina Propria)
2- Submucosa
3- Fibro-Cartilagenous coat
7- Bronchi
It is composed of:
1- Extra-pulmonary bronchi
2- Intra-pulmonary bronchi:
a- Bronchioles
b- Terminal Bronchioles
c- Respiratory Bronchioles
8- The Alveoli, Alveolar Sacs and Alveolar Ducts
•Alveolar Ducts : Long branching passages arise from
respiratory bronchioles.
•Alveolar Sac : is a group of alveoli which open into a
common central space (the atrium).
•The alveoli : are the minute "air spaces" which open into
the alveolar ducts, and to alesser extent into the
respiratory bronchioles.
The Alveolar Phagocytes:
They are phagocytic cells present free inside the lung
alveoli. e.g
1- Dust Cells:
2- Heart Failure Cells:
Types of alveolar epithelial cells:
1. Type I: Pneumocytes: flat squamous cells, constitute
the major of the alveolar lining cells (95%).
2. Type II: pneumocytes: cuboidal cells represent 5% of
the alveolar lining cells.