Respiratory System

By

Prof. Dr. Mona Mohammed Zoair

Professor of Anatomy& EmbryologyTanta Faculty Of Medicine

The respiratory system consists of:

1- Nasal passages2- Pharynx

(shared with alimentary canal)3- Larynx

4- Trachea5- Bronchi6- Lungs

Nasal CavityHas:-Floor: hard

palate- Roof: for

olfaction- Lateral wall:1- above by orbit

and ethmoid sinus

2- below by maxillary sinus

Pharynx

2

3

4

5

6

1

-It is a tube 13 cm long

-Extends from base of skull to

6th cervical vertebra

It is divided into:1- Nasopharynx:

behind nasal cavity above soft palate

2- Oropharynx: behind mouth cavity from soft palate to epiglottis

3- Laryngeopharynx: behind larynx from epiglottis to cricoid cartilage

Larynx-it is the organ of

phonation-it is 4 cm in length-Extends from epiglottis - to trachea- Formed of 2 thyroid

cartilages- -They meet in midline

in Adam’s apple- Thyroid cartilages are

attached inferiorly to cricoid cartilages

epiglottis

trachea

- The inlet of larynx is guarded by epiglottis (leaf shaped elastic cartilages)

- Vocal folds are a pair of folds in laryngeal cavity leaving a fissure between them

Trachea- A tube of fibro-

elastic membrane maintained by C- shaped cartilage

- Posteriorly it is closed by trachealis muscle

- Extends from 6th cervical vertebra to the level of angle of Louis where it is divided into 2 bronchi

- It is about 6 inches long

Bronchi

4.5

cm2.5

cm

25 45

Rt. bronchus

Lt. bronchus

-Wider

-Shorter (2.5 cm)

-Bifurcates before entering the lungs

-Makes 25 degrees with vertical

-Narrower

-Longer (4.5 cm)

-Bifurcates after entering the lungs

-Makes 45 degrees with vertical

Foreign bodies enter Rt. Bronchus than Lt. bronchus

Pleura- It is a closed

sac invaginated from medial side by the lung

- It has two layers:

1- Visceral covers the lung

2- Parietal lines chest wall

Parietal pleura

Visceral pleura

Lungs

- Each lung looks like half a cone

- It has an apex and a base (diaphragmatic surface)

-Borders of the lung:

1- anterior border2- posterior border3- inferior border

Surfaces of the lung:

1- Costal surface2- Mediastinal

surface3- Diaphragmatic

surface (base)

Fissures of the lungs:

1- Oblique fissure: from 3rd thoracic vertebra to 6th rib

2- Horizontal fissure (only in the right): from 4th costal cartilage to meet oblique fissure

Broncho- pulmonary segments- It is the functional

unit of the lung- Each unit is supplied

by:1- Segmental

bronchus2- Pulmonary artery3- Pulmonary vein

Differences between right and left lungs

Right lungLeft lung

- Short, wide with no cardiac notch

- Has 3 lobe separated by 2 fissures

- Contains 10 bronchopulmonary segments:

3 in upper lobe

2 in middle lobe

5 in lower lobe

- Long, narrow with cardiac notch

- Has 2 lobes separated by 1 fissure-Contains 8 bronchopulmonary segments:

2 in upper lobe

2 in lingular lobe

4 in lower lobe

Right lung (10):

- 3 in upper lobe

- 2 in middle lobe

- 5 in lower lobe

Left lung (8):

- 2 in upper lobe

- 2 in lingular lobe

- 4 in lower lobe

Thank You