Respiratory System

By: Maghan DasBscN Student atDow University of Health SciencesMaghan Das

Respiratory System RESPIRATORY SYSTEM CONSIST OF: NOSE PHARYNX (THROAT)LARYNX (VOICE BOX) TRACHEA (WIND PIPE) BRONCHI BRONCHIOLES ALVEOLI

Pharynx

Larynx

Trachea

Bronchioles

Nose

AlveoliMaghan Das

Maghan Das

Conti:

Structurally respiratory system consist of two parts

The upper Respiratory System The lower Respiratory System

The upper Respiratory System Nose Pharynx

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The Lower Respiratory SystemConti:

Larynx (Voice Box) Trachea (Wind Pipe) Bronchi Bronchioles Alveoli

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Conti

Functionally, the reparatory system is consists of:

The conducting zone

The respiratory zone

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The conducting zone

The conducting zone consist on: Nose Pharynx Larynx Trachea Bronchi Bronchioles Terminal Bronchioles

Function

( filter, warm and filter the air)

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The respiratory zone

Respiratory Bronchioles Alveolar ducts Alveolar sac Alveoli

Function (Gas exchanges between air and blood)

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Nose

Nose can be divided into external and internal portions.

External Nose The external nose consists of a supporting framework of bone and

hyaline cartilage. Frontal bone, nasal bone, maxillae form bony framework of the

external nose. The cartilages framework of external nose consists of:

Septal cartilages Lateral nasal cartilages Alar cartilages

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Internal nose

Internal nose is a large cavity in the anterior aspects of the skull.

It lies interior to nasal bone and superior to mouth.

It lined with muscle and mucous membrane The space between internal nose is called

nasal cavity. Interior portion of the nasal cavity just

inside the nostrils called vestibule.

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Conti

Mucous secreted by the goblet cells moistens the air and traps the air particles.

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Olfactory Nerve

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Nose

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Nose

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Nose

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Pharynx

It is funnel shaped tube about 13cm long. It is chamber shared by digestive and respiratory

system. It starts at the internal nares and extends to the

level of cricoid cartilage. Pharynx can be divided into three anatomical

regions. Nasopharynx (Superior portion) Oropharynx (Intermediate portion) Laryngopharynx (Inferior portion)

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Pharynx

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Larynx

Larynx or voice box is a short passageway that connects the laryngopharynx with trachea.

It lies on the midline of neck anterior to esophagus and through 4th to 6th cervical vertebrae.

The wall of larynx is composed of nine pieces of cartilage.

Three cartilages occurs singly Thyroid cartilage Epiglottis Cricoid cartilage

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Other three occurs in pairs Arytenoid cartilages Cuneiform cartilages Corniculate cartilages

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Thyroid cartilage

It is also known as Adam’s Apple

It consists of two fused plates of hyaline cartilage.

It is present in both male and female

It is usually larger in males due to male sex hormone (testosterone) in puberty.

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Epiglottis

It is large leaf like piece of elastic cartilage

and covered with epithelium During the swallowing, the pharynx and

larynx rise. Elevation of pharynx widens it to receive food or drink

Elevation of larynx causes the epiglottis to move down and form a lid over glottis, closing it off.

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Cricoid Cartilage

It is a ring of hyaline cartilage and forms the inferior wall of the larynx

Arytenoid Cartilage It is paired Arytenoid Cartilages It is triangular pieces of hyaline cartilages. They attach the vocal folds and intrinsic

pharyngeal muscles

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Corniculate cartilages

It is paired cartilages. It is like small horn Small horn shaped pieces are made up by elastic

cartilage. It is located at apex of each arytenoid cartilages. They are supporting structures of epiglottis. Cuneiform Cartilages It is paired Cuneiform Cartilages. It is composed of club shaped elastic cartilages. It supports the vocal cards Maghan Das

Trachea

It is also known as wind pipe. It is tubular passageway for air It is 12cm long and 2.5cm in diameter. It is located anterior to esophagus. It is divided into right primary and left primary bronchi

Layers of tracheal wall

Mucosa Submucosa Hyaline cartilage Adventitia Maghan Das

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The walls of trachea are supported by 20 tracheal cartilages.

Tracheal cartilages are like C shaped. These C shaped cartilages stiffen the

tracheal wall and protects its collapse Adventitia of the trachea is consists of

areolar connective tissues

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Bronchi

At the superior border of the 5th thoracic vertebrae, trachea divides into right primary bronchi and left primary bronchi which goes into lungs.

The right bronchi is more vertical, shorter, wider than left primary bronchi.

It is lined by pseudostratified ciliated columnar epithelium.

At the point where trachea divides into right and left is known as carina.

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The primary bronchi divides into secondary bronchi (Lobar bronchi.

The secondary bronchi divides into 9 or 10 tertiary bronchi (Segmental bronchi)

Tertiary bronchi divides into bronchioles. Bronchioles divides into terminal bronchioles. The terminal bronchioles divides into respiratory

bronchioles. This extensive branching is known as bronchial

tree

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Alveolar ducts

Respiratory bronchioles open into expensive chambers called Alveolar ducts.

These passageway ends at alveolar sacs.

Alveolar sacs It is common chambers connected to

individual alveoli

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Alveoli

Alveoli is a cup shaped out pouching lined by simple squamous epithelium.

Alveolar cells Type 1 alveolar cells: It is simple squamous epithelial cells. It is main sites of gas exchange.

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Type 11 alveolar cells:

It is also known as septal cells. It secretes the alveolar fluid, which moist the air. It produces the surfactant. Surfactant is complex mixture of phospholipids and

lipoprotein. Surfactant lowers the surface tension of alveolar fluid,

which reduces the tendency of alveoli to collapse.

Alveolar macrophages (Duct cells):It removes the fine dust or other debris from the alveolar sacs Maghan Das

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Respiratory Zone of Lower Respiratory Tract

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Lungs

Lungs are paired, cone-shaped organs in the thoracic cavity. They are separated from each other by the heart and other

structures in the mediastinum. The outer covering of lungs is called pleura. Pleura is composed of pleural membrane. Pleural membrane has two layers

Partial pleura Visceral pleura Pleural fluid lubricates the both membranes and

prevents from friction

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Conti:

Lungs extend from the diaphragm to just slightly superior to the clavicles and lie against the ribs anteriorly and posteriorly.

Broad inferior portion is base which is concave.

Narrow superior portion is called apex.

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Blood Supply to lungs

Pulmonary arteries Pulmonary vein Bronchial arteries( it the branch of aorta

which deliver the blood to the lungs)

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Respiratory System Functions

Transfer of O2 (Oxygen) from atmosphere to tissues

Transfer the CO2 ( Carbon Dioxide) from the tissues to the air

Produces sound

Contains receptors for smell

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Breathing

Breathing (pulmonary ventilation). consists of two cyclic phases:

Inhalation, also called inspiration - draws gases into the lungs.

Exhalation, also called expiration - forces gases out of the lungs

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Pulmonary ventilation = exchange of gases between lungs and atmosphere

External respiration = exchange of gases between alveoli and pulmonary capillaries

Internal respiration = exchange of gases between systemic capillaries and tissue cells

Respiratory events

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References

Tortora, J. G., Derrichson, B. (2006).Principles of Anatomy and Physiology. (11th ed). USA: New York. John Willey 7 sons , Inc.

Martini, H. F. (200). Essentials of Anatomy and Physiology. (2nd ed). USA: New Jersey. Prentice Hall.

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