Human Respiratory system.ppt

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The Respiratory System Welcome Presented By: Ms.Monika MB

Introduction of Respiratory system:

Introduction of Respiratory system It is the system under which the respiration takes place in the human beings. it consists of the working of the group of the organs: Nose Pharynx (throat) Larynx (voice box) Trachea (wind pipe) Bronchi Bronchioles Lungs

Respiratory Overview Picture:

Respiratory Overview Picture Nasal Cavity Nose Mouth Bronchus Bronchiole Alveolus Diaphragm Throat (pharynx) Windpipe (Trachea) Left lungs Ribs MB

Define Respiration :

Define Respiration It is the process of exchange of O2 & CO2 in between the atmosphere & body cells is called respiration. This process include ventilation i.e. inhalation & exhalation of air.

Parts of Respiratory system:

Parts of Respiratory system The respiratory system consist of two parts. THE UPPER RESPIRATORY SYSTEM THE LOWER RESPIRATORY SYSTEM


A) THE UPPER RESPIRATORY SYSTEM It include the organs of the upper respiratory tract: E.g.: Nose & Pharynx .

Nose and Mouth Picture:

Nose and Mouth Picture Nasal Cavity Nostril Oral Cavity Pharynx Here is a picture of your nasal and oral cavity . MB

1) Nose & Nasal cavity:

1) Nose & Nasal cavity The nose & nasal cavity is the main route of air entry. It consist of the large irregular cavities divided into two equal; passage are called nasal cavities.

Division of Nose:

Division of Nose The nose is divided into two portions: ( EXTERNAL PORTION & INTERNAL PORTION) External Portion : The external nose consist of a framework of bones ,hyaline cartilage covered with muscles ,skin & mucus membrane. The frontal bone ,nasal bone and maxillae of the bony framework of the external nose. External nose consist of two opening called NOSTRILS .


B) INTERNAL NOSE The internal nose is a large cavity. The space within the internal nose is called NASAL CAVITY . The NASAL SEPTUM divide the nose cavity into the right and left side. When air enters into the nostrils .it passage through the hairs that filters out large dust particles.

Anatomy of nose:

Anatomy of nose ROOT : (superiorly) it is attached from the frontal bone. APEX : Tip of the nose BRIDGE : Bony framework of nose formed by nasal bone . EXTERNAL NARES : Nostrils opening into the nasal cavity.


RESPIRATORY FUNCTIONS OF NOSE The nose act as an important respiratory organ & it has many functions that are given below: WARMING : the nose helps to make the breathe warm due to high vascularity of the mucosa. - Due to thick mucosa nose is able to warm the inhalated & expelled air.


Cont…………………d b) Provides an airway for respiration c) Resonating chamber for speech d) Houses of olfactory receptors f) FILTERING & CLEANING : - It helps in filtering of inhaled air occur due to the hair present in nose.


Cont………….d The hairs traps the large particles & smaller particles such as dust & microbes. With the filtering & cleaning of air the human beings use the clean & fresh air. g) HUMIDIFICATION : as the air passage in the nostril ,the water vapors also gets inside with the moist air and helps in the humidification. Excessive humidification results into the irritation of the nasal mucosa & results to the sneezing.

2) Pharynx ( the throat):

2) Pharynx ( the throat) The pharynx or a throat is a funnel shaped tube of about 13 cm in length. It starts at the internal nares & extend to the level of the cricoid cartilage.

Position of pharynx:

Position of pharynx POSTERIORLY : The pharynx lies posterior to the nasal & oral cavities . Superiorly : it is superior to the larynx . Anteriorly : It lies just anterior to the cervical vertebrae.

Division of the pharynx:

Division of the pharynx THE PHARYNX IS DIVIDED INTO THE THREE PARTS : Nasopharynx Oropharynx Laryngopharynx

a) Nasopharynx :

a) Nasopharynx The superior portion of the pharynx is called NASOPHARYNX . It lies posterior to the nasal cavity and extends to the soft palate. Through the internal naries ,the nasopharynx receive air from the nasal cavity. The nasopharynx is lined with pseudostratified ciliated columnar epithelium. The nasopharynx also exchange small amount of air with auditory tubes to equalize the air pressure b/w the pharynx & middle ear.

b) Oropharynx :

b) Oropharynx The intermediate portion of the pharynx is called oropharynx.. It lies posterior to the oral cavity & extends from the soft palate inferiorly to the level of the hyoid bone. This portion of he pharynx has both respiratory & digestive functions because it is a common passageway for air ,food & drink. Two pairs of tonsils , THE PALATINE & LINGUAL TONSILS are found in the oropharynx.

c) Laryngopharynx:

c) Laryngopharynx The inferior portion of the pharynx is called laryngopharynx. It begins at the level of hyoid bone and opens in to the esophagus posteriorly and the larynx anteriorly. Life the oropharynx ,the laryngopharynx is both respiratory & digestive pathway .

Functions of the pharynx:

Functions of the pharynx PASSAGEWAY OF AIR & FOOD : - The pharynx is a organ which involved in both the respiratory & digestive system. Air passes through the nasal cavity. Food passes through the oral cavity.

2) Warming & humidifying:

2) Warming & humidifying As the air gets warm in the nose like the same manner the air get warm & moistened as it passes through the pharynx.


Cont………….d c) TASte : Pharynx helps to make the sense of the taste of food . d) hearing : Pharynx also helps in hearing. - As the auditory tube extend from the nasopharynx to middle ear. It allows the air to enter in the middle ear. With the help of air pressure the human becomes able to hear. e) SPEECH : pharynx helps to produce voice & results into speech.


3) LARYNX (VOICE BOX) The larynx or voice box is a short passageway that connects the laryngopharynx with the trachea. It lies in the midline of the neck anterior to the esophagus at the level of 3 rd ,4 th ,5 th & 6 th cervical vertebrae. At the puberty the size of the larynx b/w the sexes get different. i.e.: the size of the larynx become large in males.




A) THE EPIGLOTTIS (1) The epiglottis (epi =OVER ,glottis=TONGUE) is a large leaf shaped cartilage. The stem of the epiglottis is attached to the anterior of the thyroid cartilage & hyoid bone


Cont…………..d The epiglottis helps to close off the larynx during swallowing & protects the lungs from accidental inhalation of foreign objects. when small particles of dust ,smoke ,food or liquids pass into the larynx ,a cough reflex occurs ,usually expelling the material.

2) The thyroid cartilage :

2) The thyroid cartilage The thyroid cartilage consist of two fused plates of hyaline cartilage in the anterior of the larynx. It forms a v- shaped notch known as thyroid notch. it is present in both males & females but is usually larger in males at puberty due to influence of male sex hormones.

3) The arytenoid cartilage (2):

3) The arytenoid cartilage (2) It is the triangular shaped cartilage made up of the hyaline cartilage. It is located at the posterior & superior of the cricoid cartilage. They are attached to the vocal cords. & helps to produce sounds.

4) The cricoid cartilage (1):

4) The cricoid cartilage (1) The cricoid cartilage ( KRI-Koyd = Ring like): it is a ring like structure made up of hyaline cartilage that lies below the thyroid cartilage. It is attached to the first ring of cartilage of the trachea.

5)The corniculate cartilage (2):

5)The corniculate cartilage (2) The paired corniculate cartilage are horn shaped pieces of elastic cartilage . They are located at the apex of each arytenoids cartilage. They are supporting structure for the epiglotti s .

Paired Cuneiform Cartilage:

Paired Cuneiform Cartilage Paired Cuneiform Cartilage: The cuneiform cartilages of the larynx are two small, elongated pieces of elastic cartilage , placed one on either side, on the surface of the mucous membrane , It is Club-shaped pieces anterior to the corniculate cartilages. It support the vocal cords.

Functions of the larynx:

Functions of the larynx PRODUCTION OF SOUND : larynx helps to produce sound with pitch ,volume and tone. PROTECTION OF LOWER RESPIRATORY TRACT : During swallowing ,the larynx moves upward. The epiglottis helps to close the larynx & helps the food passes into the esophagus & not into the respiratory passage. c ) PASSAEGE WAY FOR AIR : The larynx helps to maintain the passageway of air between the pharynx & trachea.


Cont………………d HUMIDIFYING ,FILTERING & WARMING : The inspired air gets humidified ,filtered & warmed when it passes through the larynx.

4) Trachea (windpipe):

4) Trachea (windpipe) The trachea or windpipe is a tubular passageway for air . it is 12 cm in length. & 2.5 cm in diameter. It is located anterior to the esophagus. It extend from larynx to the level of 5 th thoracic vertebrae.


Cont…………………..d The trachea is divided into left & right bronchi. The trachea consist of 16-20 incomplete ,horizontal rings of hyaline cartilage ,resembles to the letter C. They are stacked one to top of another. These rings are felt through the skin inferior to the larynx. The open part of each C shaped cartilage faces the esophagus.


Cont………………d The C shaped cartilage provides semi rigid support to the trachea ,so that the tracheal wall dose not collapse during inhalation & helps to prevent to obstruction of the air passageway.

4) Trachea (windpipe):

4) Trachea (windpipe) The trachea or windpipe is a tubular passageway for air . it is 12 cm in length. & 2.5 cm in diameter. It is located anterior to the esophagus. It extend from larynx to the level of 5 th thoracic vertebrae.

Positioning of the trachea:

Positioning of the trachea Superiorly : the larynx is superior to the larynx. Inferiorly: the left & right bronchi are inferior to the trachea. Anteriorly: the thyroid gland Posteriorly: the esophagus.

Functions of the trachea:

Functions of the trachea A) SUPPORT & PATENCY : The trachea consist of C shaped cartilage. Theses cartilage provides semisolid support to the trachea. So that it does not collapse during inhalation & helps to maintain patency. b) COUGH REFLEX : when the foreign objects inhaled in trachea with the air ,the trachea helps to produce the cough reflex to expel the foreign material from the mouth.


Cont………….d c) Warming ,humidifying & filtering : As reaching the air into the trachea the air gets filter ,warm & humidified in trachea.

5) Bronchi & bronchioles:

5) Bronchi & bronchioles At the border of 5 th thoracic vertebrae ,the trachea divides into the two primary bronchi: At the point where trachea divides into right & left primary bronchi .an ridge is called carina a) THE RIGHT PRIMARY BRONCHUS B)THE LEFT PRIMARY BRONCHUS .


A) THE RIGHT PRIMARY BRONCHUS The right primary bronchus goes into the right lung. Right primary bronchus is wider & shorter more vertical than the left bronchus. It is 2.5 cm long Like the trachea ,the primary bronchus contains C shaped rings of cartilages & lined by pseudo stratified ciliated columnar epithelium.

b) The left primary bronchus:

b) The left primary bronchus The left primary bronchus is narrower than the right primary bronchus. It is 5 cm long The left primary bronchi gets into the left lung On entering the lung ,the primary bronchus divides to form smaller bronchioles


Cont…………….d On entering the lungs ,the primary bronchi divide to form smaller bronchi-----THE SECONDARY BRONCHI. The secondary bronchi continue to branch forming still smaller bronchi -----called TERTIARY BRONCHI These tertiary bronchi divides into bronchioles. Bronchioles again turn them into even smallest ones branches & tubes called terminal bronchioles.


Cont……………..d This extensive branching from the trachea resembles an tree & is commonly referred to the bronchial tree.

b) Bronchioles :

b) Bronchioles The bronchioles are the first airway branches that no longer contain cartilage. They are branches of the bronchi. The bronchioles terminate by entering the circular sacs called alveoli The branches subdivides called bronchioles.

Bronchial tree:

Bronchial tree Trachea Primary bronchi terminal bronchioles Secondary bronchi Tertiary bronchi Bronchioles

Functions of the bronchi:

Functions of the bronchi CONTROL OF AIR ENTRY : The bronchi controls the air entry & regulates the air entry in the lungs. WARMING & HUMIDIFYING : The bronchies helps the air to warm & humidified when it reaches to the bronchi. SUPPORT & PATENCY : The C shaped rings of the bronchi helps to provide semi solid support to prevent the collapse & helps to maintain the patency.


Cont…………………d d) COUGH REFLEX : If the foreign objects inhaled in the bronchies with the air ,the bronchi produces cough reflexes to expel out the foreign objects

6) lungs:

6) lungs Lungs are the paired ,cone shaped organs & lying on each side in the thoracic cavity. i.e. : The right lung The left lung . It is the main respiratory organ Due to the space occupied by the heart ,the left lung is about 10 % small than the right lung. The lung extends from the diaphragm slightly superior to the clavicles & lie against the ribs in posterior & anterior.


Cont…………………d Pleural cavity contains small which contains small amount of lubricating fluids secreted by membranes. The pleural fluid reduces friction between the membranes.


Cont…………………d The superficial layer of the wall of the thoracic cavity is called parietal pleura. The deep layer of the thoracic cavity is called visceral pleura. The cavity b/w the parietal pleura & visceral pleura is called pleural cavity. These two layers of parietal pleural & visceral pleura is made up of serous membrane is called pleural membrane. This membrane helps to protects the lungs.

Lungs consist of ::

Lungs consist of : THE APEX : The narrow superior portion of the lungs is called apex. The apex of the lungs lies superior to the medial third of the clavicle. The anterior ,lateral & posterior surface of the lungs lie against the ribs. THE BASE : The broad inferior portion of the lungs is called base. - The base of the lung extend from the sixth costal cartilage.


Cont…………..d c) THE COSTAL SURFACE : The surface of the lungs lying against the ribs is called costal surface. d) THE MEDIAL SURFACE : It is the medial region & posterior part of the lung is called hilus. Through the hilus the bronchi ,pulmonary blood vessels , lymphatic vessels ,nerves enters & exit out from the lungs.

Surface anatomy of the lungs:

Surface anatomy of the lungs The lungs consists of fissure & lobes: a) FISSURE : it is defined as the cracks in the mucous membrane is called fissure. - IN RIGHT LUNG IT HAS TWO FISSURES: HORIZONTAL FISSURE OBLIQUE FISSURE IN LEFT LUNGS ONLY 1 FISSURE IS PRESENT 1) OBLIQUE FISSURE


b) LOBES The section of an organ separated from neighboring parts by fissure. The right lung has three lobes. Each lobe is divided by fissure.


Cont……………………..d Superior lobe Middle lobe Inferior lobe

1) Superior lobe:

1 ) Superior lobe The upper lobe is called superior lobe. Both the lungs have oblique fissure which extends inferiorly & anteriorly. A) IN LEFT LUNG : The oblique fissure separates the superior & inferior lobe. b) IN RIGHT LUNG : The oblique fissure from the superior part seprates the superior lobe from the inferior lobe.

2) Middle lobe:

2) Middle lobe Middle lobe is only present in right lung. It is separated by the horizontal fissure & posterior part of the oblique fissure.

3) Inferior lobe:

3) Inferior lobe The lower lobe is called inferior lobe. IN RIGHT LUNG : The inferior part of the oblique fissure divides the inferior lobe from the middle lobe IN LEFT LUNG : The oblique fissure divides the superior & inferior lobe.

Functions of the lungs:

Functions of the lungs WARMING : it helps to make the air warm as it reach to the lungs. PULMONARY CIRCULATION: - in pulmonary circulation the flow of the blood from the right ventricles through the pulmonary artery (i.e.: right pulmonary & left pulmonary artery)


Cont…………………d Then it is circulated to the lungs where carbon dioxide exchanged with oxygen & back through the pulmonary veins to the left atrium.

Scheme of pulmonary circulation:


7) Alveoli:

7) Alveoli The alveoli are tiny air sacs within the lungs where the exchange of oxygen and carbon dioxide takes place. It is the Delicate air sacs deep within the lungs, Oxygen from inhaled air passes through the walls of aveoli and enters the bloodstream while carbon dioxide passes out in the same way when air is exhaled


Cont…………………d Each lobule of the lungs is supplied with air by terminal bronchioles which further subdivides into respiratory bronchiole. The adult lung contain 150 million alveoli for the exchange of gases. the alveoli sac consist of two or more alveoli that share a common opening.


Cont…………..d The alveoli consist of two tyoes of alveolar epithelium cells: Type 1 alveolar cell Type 2 alveolar cell

Type 1 alveolar cell:

Type 1 alveolar cell It is also called septal cells Flat Type I cells forming the structure of a alveolar wall These cells secrete an alveolar fluid called SURFACTANT. This fluid helps the alveoli’s from drying.

Type 2 alveolar cell:

Type 2 alveolar cell These cells secrete an alveolar fluid called SURFACTANT. This fluid helps the alveoli’s from drying.

Functions of alveoli:

Functions of alveoli DEFENCE AGAINST MICROBES : the alveoli gave defence against microbes & gave protection to the lungs. WARMING & HUMIDIFYING : it helps to make the air warm & humidified - Excessive inhalation of dry & humidified air can cause the irritation of mucosa & encourage infection.

Composition of inspired & expired air:

Composition of inspired & expired air GASES INSPIRED AIR (%) EXPIRED AIR (%) A) Oxygen 21 16 b) CO2 0.04 4 c) Nitrogen 78 78 d) Water vapor variable saturated


PLEURA The pleura consist of a close sac of serous membrane which contains a small amount of serous fluid & helps to prevent the friction between lungs during breathing. It has two layers The parietal pleura The visceral pleura

a) The parietal pleura:

a) The parietal pleura It is the superficial layer of the lungs & it is made up of serous membrane. b) The visceral pleura : the deep layer of the lungs made up of serous membrane in which lungs is enclosed is called visceral pleura.] PLEURAL CAVITY : the cavity b/w the parietal pleura & visceral pleura is called pleural cavity .


FUNCTIONS OF THE PLEURA It helps to enclose the lungs It helps to gave protection to the lungs It helps to prevent the friction between the lungs during breathing.

Slide 75:

Muscles of Respiration


MUSCLES OF RESPIRATION The various muscles of respiration aid in both INSPIRATION and EXPIRATION . It helps to changes in the pressure of air within the THORACIC CAVITY . The principal muscles are the MUSCLE OF INSPIRATION diaphragm Intercostal muscle : external intercostal ,the (intercartilaginous) part of the internal intercostal muscles . Both the external intercostal muscles and the internal intercostal muscles . elevate the ribs, & helps in respiration.


Cont……….d Accessory muscles are typically only used when the body needs to process energy quickly (e.g. during heavy exercise, during the stress response, or during an asthma attack) The sternocleidomastoid (elevated sternum) scalene muscles : four pairs of muscles extending from the cervical vertebrae to the second rib; involved in moving the neck and in breathing (anterior, middle and posterior scalene) are typically considered accessory muscles of breathing . however the following muscles have also been observed contributing to the breathing:, pectoralis major & minor, upper trapezius, latissimus dorsi,


MUSCLE OF EXPIRATION During quiet breathing, there is little or no muscle contraction/relaxation involved in expiration.The abdominal muscles and the internal and innermost intercostal muscles help expel air..

The intercostal muscles :

The intercostal muscles There are 11 pairs of intercostal muscles that occupy the spaces b/w the 12 pairs of ribs. They are arranged in two layers: THE EXTERNAL INTERCOSTAL MUSCLE THE INTERNAL INERCOSTAL MUSCLE

The external intercostal muscle:

The external intercostal muscle The External intercostals are eleven in number on either side. These extend in a downward & forward direction from the lower border of the rib to upper borer of the rib. Action : The superficial external intercostals pull the ribs upwards and outwards, and drawing air into the lungs during inspiration

The internal intercostal muscle:

The internal intercostal muscle These extend in a downward & backward direction from the lower border of the rib above to the upper borer of the rib. The superficial external intercostals pull the ribs upwards and outwards, and drawing air into the lungs during inspiration. The deeper, internal intercostals, draw the ribs downward and inwards, decreasing the volume of the thoracic cavity, forcing air out of the lungs during expiration.

The diaphragm:

The diaphragm The diaphragm is a thin dome-shaped muscle which separates the thoracic cavity (lungs and heart) from the abdominal cavity (intestines, stomach, liver, etc.). It is involved in respiration, drawing downward in the chest on inhalation, and pushing upward in exhalation.

The diaphragm:

The diaphragm It forms the floor of the thoracic cavity & the roof of the abdominal cavity. The intercostal muscles & the diaphragm contracts at the same time to make the enlargement t of the thoracic cavity in all directions.

The diaphragm :

The diaphragm The diaphragm is crucial for breathing and respiration During inhalation, the diaphragm contracts, thus enlarging the thoracic cavity This reduces intra-thoracic pressure: in other words, enlarging the cavity creates suction that draws air into the lungs . The diaphragm is also involved in non-respiratory functions, helping to expel vomit , feces , and urine from the body by increasing intra-abdominal pressure.


PHYSIOLOGY OF RESPIRATION The process of the exchange of gases (02 & CO2) in the body is called respiration. The respiration process consist of three basic process: PULMONARY VENTILATION. EXTERNAL RESPIRATION INTERNAL RESPIRATION


A) PULMONARY VENTILATION It is also called breathing. It is the mechanical flow of air into & out of the lungs to maintain the pressure in one place is different from the other place. Air in the alveoli at the end of one expiration and before the beginning of another inspiration also exerts a pressure of 760 mm hg. The mechanism of pulmonary ventilation depends upon the gas pressure b/w the atmosphere & alveolar air.


Cont………….d It involve two process: INHALATION OF AIR EXHALATION OF AIR.

1) Inhalation of air:

1) Inhalation of air Breathing in of air is called inhalation of air.(o2) Inhalation is initiated by the diaphragm and supported by the external intercostal muscles . Normal resting respirations are 10 to 18 breaths per minute, with a time period of 2 seconds. During vigorous inhalation (at rates exceeding 35 breaths per minute), or in approaching respiratory failure, accessory muscles of respiration are recruited for support. These consist of sternocleidomastoid ,, and the scalene muscles of the neck. Pectoral muscles and latissimus dorsi are also accessory muscles.


Cont…………………d During forced inhalation, as when taking a deep breath, the external intercostal muscles and accessory muscles aid in further expanding the thoracic cavity .

2)Exhalation of air:

2)Exhalation of air Breathing out of air is called exhalation (co2) Exhalation is generally a passive process; however, active or forced exhalation is achieved by the abdominal and the internal intercostal muscles . During this process air is forced or exhaled out. During forced exhalation, as when blowing out a candle, expiratory muscles including the abdominal muscles and internal intercostal muscles, generate abdominal and thoracic pressure, which forces air out of the lungs.


B) EXTERNAL RESPIRATION It is defined as the exchange of gases between the lungs & the blood in pulmonary capillaries take place. exchange of gases Lungs Blood In Pulmonary Capillaries In this process blood Gains o2 & loses co2.


Cont……………..d in this process the o2 enters in the alveoli of the lungs ,then it further moves to the pulmonary capillaries via blood. It ensures proper diffusion of CO 2 from the blood into the lungs, and its subsequent excretion into the atmosphere. Breathing mechanics include breathing rate, breathing depth (volume of air in a single breath), breathing rhythmicity, location of breathing (“chest” and diaphragm), and accessory muscle activity (muscles other than the diaphragm).

c) Internal respiration :

c) Internal respiration it is systemic gas exchange. It is the exchange of gases in the systemic capillaries to TISSUS& CELLS . Exchange of gases Systemic Tissues & Capillaries Cells In internal respiration the blood gains co2 & loses o2.


Cont……………d The left ventricles pumps oxygenated blood into the aorta ,then the oxygenated blood divides into the whole system of the body. By systemic circulation the oxygenated blood loses o2 & gains co2 from the tissues & cells of the organs & become deoxygenated. This deoxygenated blood enters the pulmonary trunk & co2 reaches to the alveoli. Exhalation of co2 occurs.

Scheme of external & internal respiration:

Scheme of external & internal respiration o2 inhalation Co2 exhalation Alveoli Alveoli Pulmonary capillary Lungs Left atrium Right Ventricle Left ventricle Right atrium systemic capillaries


REGULATION OF RESPIRATION RESPIRATORY CENTRE : The basic rhythm of respiration is controlled by groups of neurons in the brain stem. The area from which nerve impulses are sent to respiratory muscles is called the respiratory centre. The respiratory centre consists of groups of neurons divided into three areas:


Cont…………..d The medullary rhythmicity area The pneumotaxic area The apneustic area .

a) The medullary rhythmicity area :

a) The medullary rhythmicity area Group of neurons located in medulla oblongata. The medullary rhythmicity area in the medulla oblongata controls the basic rhythm of respiration. The medullary rhythmicity consist of both inspiratory & expiratory areas.


Cont………d During quiet breathing ,inhalation lasts for about 2 seconds & exhalation lasts for about 3 seconds. So it is Active for 2 sec during inspiration & quiet for 3 sec during expiration. Nerve impulses are generated in the insipiratory area & establish the basic rhythm of breathing.


Cont………..d When the nerve impulses reach the diaphragm & external intercostal muscles ,the muscle contracts & inhalation occurs. The neurons of the expiratory area remain inactive during quiet breathing.

b) Pneumotaxic area:

b) Pneumotaxic area It is present in the upper Pons of brain . Which transmit impulses to the inspiratory area. The major effect of theses nerve impulses is to turn off the inspiratory area before the lungs become too full of air. In other words ,the impulses shorten the duration of the inhalation .

c) Apneustic area:

c) Apneustic area It is present in the lower Pons. This area sends stimulatory impulses to the inspiratory area and helps in prolongs inhalation. The result is a long & deep inhalation.

Characteristic of normal respiration:

Characteristic of normal respiration ELASTICITY : this is the ability of the lungs to return to its normal shape after expandation after each breathing is called elasticity. COMPLIANCE : the lungs permits the alveoli to inflate during inhalation. The healthy lungs inflates with very little efforts. When compliance is low ,the efforts needs to inflate the lungs is greater.


Cont…………..d 3) AIRWAY RESISTANCE : when airway obstructed ,more respiratory efforts is required to inflate the lungs.

The Mechanism Of Respiration:

The Mechanism Of Respiration The various structures that are involved in the respiration mechanism are the respiratory passage, the lungs, the outer and inner intercostals muscles, the diaphragm and the muscles attached to the diaphragm. The mechanism by which the respiratory acts are consists of the partly fixed and partly movable bony and cartilaginous framework of the chest and of the muscles , also which form a large part of the walls of that cavity. The breathing movements are controlled by the three respiratory centers of the medulla oblongata. The three respiratory centre (in medulla oblongata) and pneumotaxic centre

The Mechanism Of Respiration:

The Mechanism Of Respiration Breathing is largely driven by the muscular diaphragm at the bottom of the thorax. Air enters through the oral and nasal cavities; it flows through the larynx and into the trachea, which branches out into bronchi. The rib cage also is able to expand and contract to some degree, through the action of other respiratory and accessory respiratory muscles.


Cont………d As a result, air is sucked into or expelled out of the lungs,. In mechanism of respiration air comes in and flows out by the same route). The chest volume is changed by the diaphragm and intercostal muscles. The diaphragm and intercostal muscles that move ribs make lungs expand and contract and this causes respiration.

The Mechanism Of Respiration:

The Mechanism Of Respiration The area of the diaphragm is about 300 square centimeters. When it goes down for 1 centimeter, the volume of the chest increases for 250 -- 300 cubic centimeters. Then, air is drawn into lungs for the volume.

Gaseous exchange in lungs:

Gaseous exchange in lungs In The lungs' intake of oxygen and removal of carbon dioxide is called gas exchange. Gas exchange is part of breathing. Breathing is a vital function of life The main function of the respiratory system is gaseous exchange. This refers to the process of Oxygen and Carbon Dioxide moving between the lungs and blood . In the lungs oxygen and carbon dioxide (a waste product of body processes) are exchanged in the tiny air sacs (alveoli) at the end of the bronchial tubes.


Cont………..d The alveoli are surrounded by capillaries. When a person inhales, oxygen moves from the alveoli to the surrounding capillaries and into the bloodstream. At the same time, carbon dioxide moves from the bloodstream to the capillaries and into the alveoli. The carbon dioxide is removed from the lungs when a person exhales

Gaseous exchange of tissues & cells:

Gaseous exchange of tissues & cells It is the exchange of gases in the systemic capillaries to TISSUS& CELLS . In internal respiration the blood gains co2 & loses o2. The left ventricles pumps oxygenated blood into the aorta ,then the oxygenated blood divides into the whole system of the body. By systemic circulation the oxygenated blood loses o2 & gains co2 from the tissues & cells of the organs & become deoxygenated. This deoxygenated blood enters the pulmonary trunk & co2 reaches to the alveoli. Exhalation of co2 occurs .

Carrier of o2 & Co2:

Carrier of o2 & Co2 TRANSPORT OF OXYGEN: It is the process by which oxygen is absorbed in the lungs by the hemoglobin in circulating deoxygenated red cells and carried to the peripheral tissues. The process is made possible because hemoglobin has the ability to combine with oxygen present at a high concentration, such as in the lungs. Or process of transfer of oxygen around the body either attached to hemoglobin.


Cont…………..d The major function of cardiovascular & respiratory system is to provide an adequate amount of oxygen in tissues. Failure to accomplish this goal results in tissue hypoxia. Oxygen is transported in the blood by two ways: In physical solution in the plasma as dissolved o2. In chemical combination with Hemoglobin.


cont………..d Hb ,pa protein present in RBC It represents the major means of transporting o2 in the blood. When completing saturated with oxygen ,1 gm of hb is capable of combining with 1.34 ml of oxygen.

Transport of Carbon dioxide:

Transport of Carbon dioxide carbon dioxide transport: it is defined as the process in which carbon dioxide passes from tissues to blood by diffusion. Transport is carried out by the blood in the following ways: 1. DISSOLVED CO2 - Carbon dioxide is much more soluble in blood than oxygen - About 5 % of carbon dioxide is transported unchanged, simply dissolved in the plasma


Carbon dioxide combines reversibly with hemoglobin to form carbaminohaemoglobin. Carbon dioxide does not bind to iron, as oxygen does, but to amino groups OF the hemoglobin. 2. BOUND TO HAEMOGLOBIN AND PLASMA PROTEINS

Pulmonary ventilation volume:

pulmonary ventilation . The total volume of gas per minute inspired or expired. While at rest ,a healthy adult averages 12 breathe a minute with each inhalation & exhalation & moving about 500 ml of air into & out of the lungs. The volume of one breathe is called the tidal volume (Vt) The minute volume (MV) ---the total volume of air inhaled & exhaled each minute Pulmonary ventilation volume


The apparatus commonly used to measure the volume of air exchanged during breathing & respiratory rate is a spirometer or respirometer. The record is called spirogram. Inhalation is recorded as an upward deflection & exhalation is recorded as an downward deflection. In a typical adult about 70% of the tidal volume(350 ml) actually reaches the respiratory portion of the respiratory system & 30 % remains in the airways of the nose ,pharynx ,larynx ,trachea ,bronchi & bronchioles. Cont……………d


By taking a very deep breathe ,a person can inhale a 500 ml of air ,this additional inhaled air called insipiratory reserve volume is about 3100 ml. Even after the expiratory volume is exhaled ,air remains in the lungs. this volume which cannot be measured by spirometry is called residual volume and amounts to be about 1200 ml. Cont……….d

Alteration of diseases:

Alteration of diseases Asthma is a obstructive lung disorder that is characterized by recurring spasm of the smooth muscles in the walls of the bronchial air passage. A chronic respiratory disease, often arising from allergies, that is characterized by sudden recurring attacks of labored breathing, chest constriction, and coughing ASTHMA

Sign & symptoms:

Sign & symptoms Coughing. Coughing from asthma is often worse at night or early in the morning, making it hard to sleep. Wheezing. Wheezing is a whistling or squeaky sound that occurs when you breathe. Chest tightness. This may feel like something is squeezing or sitting on your chest. Shortness of breath. Some people who have asthma say they can't catch their breath or they feel out of breath. You may feel like you can't get air out of your lungs.

What Causes Asthma Symptoms To Occur? :

A number of things can bring about or worsen asthma symptoms Triggers may include: Allergens found in dust, animal fur, cockroaches, mold, and pollens from trees, grasses, and flowers Irritants such as cigarette smoke, air pollution, chemicals or dust in the workplace, compounds in home décor products, and sprays (such as hairspray) Certain medicines such as aspirin or other nonsteroidal anti-inflammatory drugs and nonselective beta-blockers Sulfites in foods and drinks Viral upper respiratory infections such as colds Exercise (physical activity) What Causes Asthma Symptoms To Occur?

Management of asthma:

An acute of asthma is treated by giving an inhaled beta adrenergic agonist Drug: albuterol :it helps to relax smooth muscles in the bronchioles & open up the airways Management of asthma

Chronic obstructive pulmonary disease (COPD):

Chronic obstructive pulmonary disease (COPD) refers to chronic bronchitis and emphysema, a pair of two commonly co-existing diseases of the lungs in which the airways become narrowed. This leads to a limitation of the flow of air to and from the lungs causing shortness of breath. ... or The airflow limitation is usually progressive and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases, primarily caused by cigarette smoking Chronic obstructive pulmonary disease (COPD)


It is the fourth leading cause of death after heart diseases ,cancer & cerebrovascular diseases. The common cause is cigarette smoking or second hand smoke. Other causes include air pollution ,pulmonary infection ,occupational exposure to dusts & gases and genetic factor. Cont………………..d

Sign & symptoms:

Dyspnea ( Shortness of Breath ) Chronic Cough: Chronic cough typically begins as a morning cough and slowly progresses to an all-day cough. Wheezing: Wheezing is the high-pitched sound of air passing through narrowed airways Hemoptysis Weight Loss: Patients with severe COPD work hard and burn a lot of calories just breathing Sign & symptoms

Risk Factors:

Smoke from home cooking and heating fuel Occupational dust and chemicals Gender: More common in men. M:F ratio is 5%:2.7% (in India) Increasing age Risk Factors

Management of copd:

Smoking cessation : Smoking cessation is the most important and effective step. Reduction in other risk factors : Specific measures such as the use of smokeless ‘chullahs’ should be aimed at reducing risk Substitution of solid fuels with LPG or electricity is the best approach. The “kitchen” at home should at least be located outside the living and sleeping areas. Kitchens should be adequately ventilated by providing ‘chimneys’, exhaust pipes and/or fans. Management of copd

Drugs used to treat copd:

Bronchodilators Corticosteroids Role of other drugs The use of antibiotics other than treating infectious exacerbations of COPD and other bacterial infections is not recommended. Drugs used to treat copd

Emphysema :

It is a disorder characterized by destruction of the walls of the alveoli ,producing abnormally large air spaces that remain filled with air during exhalation. Causes: it is caused by long term cigarette smoking ,air pollution & occupational exposure to industrial dust. Treatment consist of cessation of smoking &removing other environmental irritants ,breathing exercises ,use of bronchodilators and oxygen therapy. Emphysema

Chronic bronchitis:

It is a disorder characterized by excessive secretions of bronchial mucus and accompanied by a productive cough. Cause: cigarette smoking is the leading cause Symptoms: productive cough ,shortness of breathe ,cynosis. Treatment include: bronchodilators ,antibiotic ,exercises of breathing & oxygen therapy. Chronic bronchitis

Lung cancer:

Cancer that forms in tissues of the lung, usually in the cells lining air passages. Lung cancer is the leading cause of cancer death in both males &females accounting for 160,000 deaths annually. Cigarette smoke is the most common cause of lung cancer. Exposure to second hand smoke is also associated with lung cancer & heart diseases. symptoms of lung cancer are related to the location of the tumor. It may include chronic cough ,spitting blood from the respiratory tract ,wheezing ,shortness Lung cancer


Of breathe , chest pain weight loss ,fatigue , Treatment include of partial or complete surgical removal of a diseased lung ,radiation therapy and chemotherapy. Cont………………..d


respiratory disease characterized by inflammation of the alveoli with congestion caused by viruses or bacteria or irritants. The most common cause of pneumonia is the pneumococcal bacteria Those who are most susceptible to pneumonia are the elderly ,infants ,immunosuppressant's patient , cigarette smokers , and individuals with an obstructive lung disease. Sigh & symptoms: fever ,chills ,productive or dry cough ,malaise ,chest pain & dyspnea. Pneumonia


Treatment may include antibiotics ,bronchodilators ,oxygen therapy , chest physiotherapy , ( percussion & postural drainage) Cont……………d

Tuberculosis (TBC):

The bacterium mycobacterium tuberculosis produces an infectious communicable diseases called tuberculosis. It mostly affects the lungs an the pleura but may involve other parts of the body. Once the bacteria invades in body it gets multiplied &cause inflammation. If the immune system is not impaired ,the bacteria remain dormant for life. Sign & symptoms: fatigue ,weight loss .lethargy ,anorexia ,a low grade fever ,night sweats ,cough ,dyspnea ,chest pain ,hemoptysis. Tuberculosis (TBC)

Coryza & influenza:

CORYZA IS ALSO CALLED COMMON COLD . Group of viruses called rhinoviruses is responsible for about 40 % of all colds in adults. s/s: sneezing ,excessive nasal secretions ,dry cough & congestion Complications' include: sinusitis ,asthma ,bronchitis ,ear infection & laryngitis INFLUENZA ( FLU) IS ALSO CAUSED BY A VIRUS. Its symptoms include chills ,fever (usually higher than 101 degree f) ,headache& muscular aches. Coryza & influenza

Pulmonary edema:

It is an abnormal accumulation of fluid in the interstitial spaces and alveoli of the lungs. The edema may arise from increased pulmonary capillaries. The most common symptoms is dyspnea ,other include: wheezing ,tachypnea ,restlessness ,a feeling of suffocation ,cyanosis . Treatment consist of administering oxygen ,drugs that dilate the bronchioles ,diuretics to excrete excess fluid from body. Pulmonary edema

Acute respiratory distress syndrome (ARDS):

It is the form of respiratory failure characterized by excessive leakiness of the respiratory membranes& severe hypoxia. Situations that cause ARDS include drowning ,drug reactions ,inhalation of an irritating gas such as ammonia ,allergic reactions ,various lung infections such as pneumonia ,tb etc. Acute respiratory distress syndrome (ARDS)