Respiratory system

Mrs. Jenny.JClinical instructor,

FAHS.

Introduction

• Thorax forms upper part of the trunk of the body.• The trunk of the body is divided by the diaphargm, into an

upper part called the thorax.• And lower part called the abdomen.• It is supported by a skeletal frame work- Thoracic cage • The thoracic cavity contains- Lungs & heart.

Skeleton of the thorax• Also known as the thoracic cage• It is an osseocartilaginous, elastic

cage.• Designed for increasing and

decreasing the intrathoracic pressure, so that air is sucked into the lungs during inspiration & expelled during expiration.

FormationAnteriorly - sternumPosteriorly – 12 thoracic vertebraeEach side – 12 ribs with their cartilage

• Shape – Truncated cone.arrow above broad below

Bones of the thorax

Ribs( Costae) Sternum Vertebral columnRibs• 12 ribs on each side forming the greater

part of the thoracic skeleton• Ribs are bony arches arranged one

below the other• The gaps between the ribs are called

intercostal spaces.

Sternum

It is a flat bone; The anterior median part of the thoracic skeleton

Shape- Resembles ashort sword Parts1. Upper part –Manburium2. Middle part- Body3. Lower part- Xiphoid process or

xiphisternum4. Its about 17cmlong5. It is longer in males than in

females.

Vertebral column• It is also called the spine, spinal

column or back bone.• It is the central axis of the body• It supports the body weight and

transmits it to the ground through the lower limbs.

• It is made up of 33 vertebrae. 7 cervical,12 thoracic,5

lumbar,5sacral,4 coccygeal.• Length of the spine is about 70cm in

males and about 60cm in females.• The number of vertebrae corresponds

to the number of spinal nerves.

Muscles of the thorax• Pectoralis major• Pectoralis minor • Serratus anterior• Latissimus dorsi• Diaphargm• Sternocleidomastoid muscles• External intercostal• Internal intercostal muscles

Organs of respiration

• The different organs of the respiratory system such as nose, larynx, trachea, bronchi, alveoli.

• carry out the process of respiration• All these organs play an important

role in supplying oxygen to the body.

Organs:1.Upper respiratory tract - Nasal

cavity, Pharynx, Larynx.2.Lower respiratory tract – trachea,

bronchi, lungs.

Organs of respiration

• Nose Vestibule is a part of nostrils - lined with coarse hair. Nasal septum divides the nasal cavity in two parts. The floor of nasal cavity is formed of hard and soft palates. Cartilage is an external part of the nose which forms the tip. The bony shelves which project from lateral walls of the nose

are referred to as inferior, middle and superior nasal conchae. Meatuses are the spaces present between conchae.

Pharnyx

• Pharynx is a tubular part of the respiratory system which allows the passage of air into lungs.

• It is located behind the nasal and oral cavities. The different parts of pharynx are as follows:Nasopharynx: It connects the upper portion of the throat with the nasal cavity.Oropharynx: It is located between the soft palate and upper part of epiglottis.Laryngopharynx: This part of the pharynx is located below the epiglottis. It opens into the esophagus and larynx.

Epiglottis

• It is a flap-like structure (epiglottis) which prevents food or water from entering the trachea at the time of swallowing.

• Epiglottis is composed of cartilaginous tissue. It is located at the opening of larynx (back of the tongue); the epiglottis is covered with mucous.Since the epiglottis gets abraded easily (it lies in the digestive tract), its surface is covered with a layer of non-keratinized and stratified squamous epithelial cells.

Larynx(Voice box)• It is a part of the respiratory

system which connects the trachea with laryngo pharynx.

• The larynx controls the flow of air at the time of breathing.The larynx, also known as sound box, is formed of cartilages.

• Epiglottis, thyroid and cricoid are the three important cartilages of larynx

Trachea• The trachea, also known as windpipe,

extends from larynx to bronchi.• The trachea gets branched into

bronchi. The trachea facilitates the flow of air towards the bronchi.

• Trachea lies to the anterior side of the oesophagus;

• It is tubular in shape with a diameter of 1 inch. and length of 4.25 inch.

• Length of the trachea spans between the 6th cervical and 5th thoracic vertebrae.

• The trachea is composed of 15-20 C-shaped pieces of hyaline cartilage.

Bronchi

• Bronchus (singular of bronchi) is a passage which allows the flow of air into lungs. The bronchi extend from trachea to the lungs.

• The tracheal tube, when divided into two at the caudal end, gives rise to the left and right bronchus.

• The left bronchus is shorter than the right one; the left one is sub-divided into 2 lobar bronchi; right bronchus, on the other hand, is sub-divided into 3 lobar bronchi.

Lungs Lungs occupies the major portions

of the thoracic cavity Leaves little space for the heart.

Which occupies more of the left lung.

Lungs are pair of respiratory organs - thoracic cavity

Each lung invaginates corresponding pleural cavity.

Right and left lung – mediastinum Right lung- 700g( 50-100g) heavier

than left lung

Features1. Apex- upper end2. Base- resting on diaphargm3. Three borders – Anterior,

posterior& inferior4. Two surfaces – Costal &

medial Fissures & lobes of the lungs5. Right lung - 3lobes & two fissures6. Left lung – Two lobes & one fissures.

Features• Apex It is blunt & lies above the anterior end of the first rib• Base It is semilunar and concave It rests on the diaphargm Which separates the right lung from right lobe of the liver And left lung from left lobe of the liver, Fundus of the stomach, &

spleen.BordersAnterior border Anterior border is very thin It is shorter than the posterior border Posterior border It is thick and ill definedInferior border It separates the base from the costal and medial surface

Surfaces Costal surface It is large and convex Contact with the costal pleura and

the overlying thoracic wall`Medial surface Divides into Posterior or vertebral

part Anterior or mediastinal part Vertebral part- Intervertebral discs Posterior- Intercostal vessels Mediastinal – Cardiac

impressions ,& the hilum of the lung

Fissures & lobes of the lungs• Right lung• Upper, middle, & lower• Horizontal & oblique • Left lung• Upper & lower lobe• Oblique fissures• Tongue shape projection - Lingula

Pleura• Pleura is a serous membrane of

the lung• Two pleural sacs• Outer layer- parietal pleura• Inner layer – Visceral or

pulmonary pleura• Pleural cavity – between two

pleura• Pleural fluid.

• Arterial supply of the lungs• Bronchial arteries – nutrition to the bronchial tree &

Pulmonary tissue.• Deoxygenated blood- lungs- Pulmonary arteries• Oxgenated blood returned – the heart - pulmonary veins• Venous drainage of the lung• Bronchial veins- Azygos veinNerve supply of the lung • Parasymapathetic• Sympathetic - Located in the lungs

Bronchial tree• Trachea divides at the level of the 4th thoracic

vertebra – two primary bronchi• Right Primary bronchus It is 2.5 cm long Shorter & wider More line the trachea than the left primary

bronchus Inhaled particles – tend to pass more in right

lung Infections are common on the right side than

left side. • Left primary bronchus It is 5cm long Longer and narrower & more oblique than the

right bronchus.

 Together, the lungs contain approximately 2,400 kilometres of airways and 300 to 500 million alveoli.

Bronchopulmonary segments• DefinitionThese well defined sectors of the lung, each one of which is aeratedby a tertiary or segmentalbronchus. There are 10 segments on the

right side and 10 on the left.