Anatomy and physiology Respiratory system Note

Respiratory System 

         Organ of respiratory System are:

• Nose (nasal cavity)

*Pharynx

*Larynx 

*Trachea

*Two bronchi (one bronchus to each lunge) 

*Bronchioles and Smaller air passage

*Two Lungs and their covering the pleura

*muscle of breathing - The intercostal muscle and the diaphragm.

 

Nose and Nasal cavity:

* Main route of air entry and consists of Large irregular cavity divided into the two equal passage by a septum.

 Posterior bony part of Septum: is formed by Perpendicular of ethmoid bone and vomer.

Anteriorly part of septum is formed by: Hyaline cartilage

The Roof of septum is formed by:

*Cribriform plate of the ethmoid bone

*Sphenoid bone

*Nasal bone

* Frontal bone.

 

Lining of the nasal cavity:

Ciliated columnar epithelium

It consist of mucus secreting or producing cell called goblet cells

 

Nasal mucus gland:

  Secrete mucus throughout the nasal air passage.

 

Sinus:

  A sinus is a sac or cavity in any organ or tissue or an abnormal cavity or passage caused by the destruction of tissue.

 

Sinus usually refer to the par nasal sinuses, which are air cavitites in the cranial bones especially those near the nose and connecting to it.

 

Types of sinus in the body:

*maxillary sinus: largest sinus

*Ethmoid sinus

*Sphenoid sinus

*Frontal sinus

Respiratory Function of the Nose:

*warming

*filtering

*humidification

*the sense of smell:

 -specialized receptor that detect smell are located in the roof of the nose in the area of cribriform plate of the ethmoid bone and superior conchae.

 

 

Pharynx:

   The pharynx (throat) is a passage way about (12-14cm) long.

* It extend from the posterior nares, and runs behind the mouth and the larynx to level of 6^th thoracic vertebra where it becomes the esophagus.

It has 3 parts:

*nasopharynx

*oropharynx

*laryngopharynx

A) Nasopharynx: (passage of air only)

a) Lateral wall are the opening of the auditory tube also called Eustachian tube.

b) Postural wall consist pharyngeal tonsils (adenoids) consisting of lymphoid tissue.

They are most prominent in children up to approximately 7years of age thereafter they gradually atrophy.

* Eustachian tube (auditory tub)

* Pharyngeal tonsils (adenoids)

 

B) The oropharynx: (both air and food passage)

The oral part of the pharynx lies below the mouth, extending from below the level of soft plate to the level of upper part of the body of 3^rd cervical vertebra.

*the lateral wall of the pharynx blend with soft plate to form one pair of the folds on each side. Between one pair of fold on each side has collection of lymphoid tissue called palatine tonsils.

   Pharynx

       ↓

  Soft plate

        ↓↓↓

  To form two fold on each side

       ↓↓↓

  On each fold has collection of lymphoid tissues

      ↓↓↓

  Palatine tonsils

 

C) The laryngopharynx: (passage of food only)

Below the border of oropharynx (from 3^rd -6^th cervical vertebra is called laryngopharynx).

The laryngopharynx finessed at esophagus.

 

Blood and Nerve supply:

→Facial artery (pure blood)

 

Venous returning / drainage:

→ Facial vein and internal jugular vein.

Nerve supply:

→Pharyngeal plexus

(a) Parasympathetic:

    IX glossopharyngeal nerve (mixed)

    X vagus nerve (mixed)

(b) Sympathetic supply:

Superior cervical ganglia

 

Function:

(a) Passage of air and food

(b) Warming and humidifying

(c) Hearing: auditory tube →nasopharynx to middle ear.

(d) Protection: lymphatic tissue of the pharyngeal and laryngeal tonsils produces antibodies in responses to swallowed or inhaled antigens.

ֿ Tonsils are larger in children up to seven years.