ANTOMY N PHY

8/6/2019 ANTOMY N PHY

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PRESENTED BYLAXMI SHOVA HAKU DUWALBsc MLT 3rd SEMESTERSINAMANGAL, KHATMANDU


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ContentsContents Organs of respiratory system Nose and nasal cavity

Pharynx

Larynx

Trachea

Two bronchi Bronchioles and small air passages

Two lungs and their coverings, the pleura

Physiology of respiratory system

Pulmonary ventilation Diffusion of O2 and CO2 Transport of O2 and CO2 Regulation of ventilation

References


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Organs of the respiratory systemOrgans of the respiratory system

1. Nose and nasal cavity

2. Pharynx

3. Larynx

4. Trachea

5. Two bronchi

6. Bronchioles and small air passages

7. Two lungs and their coverings, the pleura


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Nose and nasal cavity Nasal cavity is the main route of air entry and

consists of a large irregular cavity divided into twoequal passages by a septum.

Posterior bony part of the septum is formed by theperpendicular plate of the ethmoid bone & the vomer.

Anteriorly, it consists of hyaline cartilage

Roof is formed by the cribriform plate of theethmoid bone and the sphenoid bone, frontal bone andnasal bones.


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Nose and nasal cavity Floor is formed by the roof of the mouth and consists

of the hard palate infront and soft palate behind

Medial wall is formed by the septum

Lateral walls are formed by the maxilla, ethmoid boneand the inferior conchae

Lined with very vascular ciliated columnar epitheliumwhich contains mucus secreting goblet cells

FUNCTIONS

Act as air conditioner where inspired air is warmed,moistened & cleaned.

Organ of the sense of smell


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Fig: Nasal cavity


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PHARYNXPHARYNX A tube of 12 to 14cm long & extends from the base of

the skull to the level of 6th cervical vertebra

Lies behind the nose, mouth & larynx

Nasopharynx Nasal part of the pharynx lies behind the nose

above the level of soft palateOropharynx Extends from below the level of soft palate to

upper part of body of 3rd cervical vertebraeLaryngopharynx Extend from 3rd cervical vertebrae to 6th cervical

vertebrae


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Structures Composed of 3 layers of tissue

A)Mucus memebrane

Nasopharynx-columnar ciliated epithelium

Oropharynx & Laryngo pharynx-stratified squamousepithelium

B)Fibrous tissue-intermediate layer

C)Muscle tissue-consists of several involuntaryconstrictor muscles


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Blood supply Artery -branch of facial artery

Vein -into facial and internal jugular vein

Nerve -parasympathetic supply by the vagus &glossopharyngeal nerve

-sympathetic supply by nerves from thesuperior cervical ganglia

Functions

Passageway for food and air Warm & moistened the air

Sensation of taste

Hearing, protection & speech


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LARYNXLARYNX

Larynx or voice box extend from root of tongue & thehyoid bone to trachea

Lies in front of the laryngopharynx at the level of

3rd,4th,5th and 6th cervical vertebrae.

Until puberty, there is little differences in the sizeof the larynx between the sexes.


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Structure Composed of several cartilages which are attached to

each other by ligament & membrane & moved bymuscles.

The main cartilages areUnpaired-Thyroid, Cricoid, Epiglottis

Paired - Arytenoid, cuneiform, corniculate

Cavity of larynx is covered with mucus membrane

Vocal fold-lined by stratified squamous epithelium

Rest-ciliated columnar epithelium


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Fig: structure of larynx(front view) Fig: structure of larynx(behind view)


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Blood supply

Artery- superior & inferior laryngeal artery

Vein -drain by thyroid rein which join interjugular vein

Nerve -parasympathetic nerve supply from superiorlaryngeal & deep laryngeal nerve which arebranch of vagus nerve

-sympathetic supply from superior cervical ganglia

Function

Provide sphincter at inlet of air passage

Voice production

Passage of air

Humidify, warm, clean air


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TRACHEATRACHEA Tube formed of cartilage and fibromuscular

membrane, lined internally by mucosa

Length:10-15cm

Begins at continuation of larynx to lower cricoidcartilage C6 terminate at carina T4

Divides into left & right bronchi at the level of sternaangle


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Structure

Lining mucosa consists ofpsedostratified ciliated columnarepithelium.

Submucosa contain seromucous

gland Deep to sumucosa is C- shaped

ring of hyaline cartilage calledtracheal ring(16-20 number),covered by perichondrium

Gap in the rings are at the back,where there is smooth muscletrachialis muscle.

Fig: trachea


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Blood supply

Artery-Inferior thyroid arteries-Bronchial artery

Vein -drain to inferior thyroid venous plexus

Nerve -parasympathetic nerve supply by therecurrent laryngeal nerve and otherbranches of the vagi

-sympathetic supply by nerves from thesympathetic ganglia

Functions Warming, humidifying and filtering

Cough reflex


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LUNGS

Cone shaped have an apex, a base, costal surfaceand medial surface

Right lung is 700gm wt, 50-100gm heavier than left

lung Right lung-2 Fissure(hoizontal and oblique)

-3 lobes(superior, middle & inferior)

-brochopulmonary segment-10


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LUNGS Left lung-1 fissure(horizontal)

-2 lobes(superior and inferior)

-bronchopulmonary segment-10

There are 2 lungs, one lying on each side of themidline in the thoracic cavity


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Pleura and pleural cavityPleura and pleural cavity Consists of a closed sac of serous membrane (one for

each lung) which contains a small amount of serousfluid called pleural cavity

The lung is invaginated (pushed into) into this sac sothat it forms two layers

a. Parietal pleura-covers thoracic wall

b. Visceral pleura-closely adhere to lung


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Blood supply Artery -Pulmonary artery(supply alveoli)

Vein -drain oxygenated blood into left atrium

of heart


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BRONCHI AND BRONCHIOLESBRONCHI AND BRONCHIOLES Trachea bifurcate at level of sterna angle into 2 principle

bronchi, one to each lung

Right bronchus is wider, shorter & more vertical than left

Each principle bronchus divide into secondary bronchi orlobar bronchi(2 on left,3 on right);supplied lobe of lungs

Each lobar bronchi divides into tertiary bronchi orsegmental bronchi ,supply specific of lungs calledbronchopulmonary segment


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Structure

Have smooth muscles & hyaline cartilage in their wall,lined by psedostratified columnar ciliated epithelium

By successive division, they become smaller & smaller,cartilage disappears and bronchi becomes bronchioles

Blood supply

Artery-Bronchial arteries

Vein -drain to bronchial veins

Nerve -parasympathetic from vagus

-sympathetic from T6-L6


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Functions Control of air entry

Warming and humidifying

Removal of particulate matter

Cough reflex


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RESPIRATORY BRONCHIOLES ANDRESPIRATORY BRONCHIOLES ANDALVEOLIALVEOLI

1mm or less in diameter, no cartilage in their wall

Lining epithelium varies from ciliated columnar &goblet cells(in primary bronchioles)to ciliated cuboidal

and secretary clara cells (in terminal and respiratorybronchioles)

Alveolar duct -cilia free simple cuboidal cell

Alveolar sac -are expanded irregular space at the

distal end of an alveolar duct


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Nerve supply

Parasympathetic fibers from the vagus nerve causebroncho constriction

Sympathetic stimulation relaxes bronchiolar smoothmuscle

Functions

External respiration Defense against microbes

Warming and humidifying


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Fig: RESPIRATORY BRONCHIOLES AND ALVEOLI


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PHYSIOLOGY OF RESPIRATIONPHYSIOLOGY OF RESPIRATIONGoals of respiration are to provide oxygen to tissue and

to remove carbon dioxide

4 major functional events

1)Pulmonary ventilation2)Diffusion of O2 and CO2 between the atmosphere and

the lung alveoli

3)Transport of O2 and CO2 in the blood and tissue fluid

to and from the cells4)Regulation of ventilation


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1 Pulmonary ventilation1 Pulmonary ventilation Means inflow and outflow of air between the

atmosphere and the lung alveoli

Lung can be expanded and contracted in two ways

By downward and upward movement of thediaphragm to lengthen or shortened the chestcavity

By elevation or depression of the ribcage toincrease or decrease the anteroposterior

diameter of the chest cavity


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Normal quiet breathing During inspiration, contraction of the diaphragm,

lower parts of the lungs move downward

During expiration, relaxation of the diaphragm,elastic recoil of the lung, chest wall and abdominalstructure compresses the lungs, air goes out


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Heavy breathing The elastic forces are not powerful enough to cause

the necessary rapid expiration, so that extra force is

achieved mainly by contraction of the abdominalmuscles, which pushes the abdominal contents upwardagainst the bottom of the diaphragm, there bycompressing the lungs.


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Natural resting position

Ribs slant downward, sternum falls backwardtowards vertebral column

During maximum inspiration

Rib cage is elevated, the ribs project almostdirectly forward, so that the sternum also movesforward


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Pulmonary volumes and capacitiesPulmonary volumes and capacities

Pulmonary volumes1. Tidal volume

Volume of air inspired or expired with each normal

breathTV=5ooml

2. Inspiratory reserve volume

Is maximum extra volume of air that can be

inspired over and above the normal tidal volumeIRV=3000ml


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3. Expiratory reserve volume

Extra volume of air that can be expired by forcefulexpiration after end of normal tidal expiration

ERV=1100ml4. Residual volume

Volume of air remain in lung after must forcefulexpiration

RV=1200ml


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Pulmonary capacities

1. Inspiratory capacityIC=IV+IRV=500ml + 3000ml=3500ml

2. Functional residual capacity

FRC=ERV +RV=(1100 + 1200)ml=2300ml

3. Vital capacityVC=IRV + ERV +TV

=(4600 + 1200)=5800ml

4. Total lung capacityTLC=VC + RV

=(4600 + 1200)=5800ml


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22. Diffusion of O. Diffusion of O22 and C0and C022 between thebetween thealveoli and bloodalveoli and blood

Gas exchange between the alveolar air and pulmonaryblood occurs through respiratory membrane throughdiffusion

Diffusion :movement of gases from higher

concentration to lower concentration


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3. Transport of O3. Transport of O22 and COand CO22 in the bloodin the bloodand tissue fluid to and from the cellsand tissue fluid to and from the cells

O2 is transported from blood to tissue in 2 forms1)Dissolved state(3%)

At the normal arterial PO2 of 95mm of Hg, about0.29 milliliters of oxygen is dissolved in every 100milliliters of water in the blood

During strenuous exercise, when hemoglobin releaseof oxygen to the tissue increases, the relativequantity of oxygen transported in the dissolved statefalls to as little as 1.5%

But if a person breathes oxygen at a very highalveolar PO2 levels, the amount transported in thedissolved state can become much greater and oxygenpoisoning occurs.


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2) Combined state(97%)

O2 molecules combines loosely & reversibly with hemepositioned of hemoglobin

When O2 is high(e.g. Pulmonary capillaries), O2 bindswith Hb, when PO2 is low (in tissue), O2 is releasefrom hemoglobin


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Co2 is transported from tissue to lung in 3 forms

1)Bicarbonate (70%)

2)Bound to Hb(23%)

3)Dissolved state(7%)

1)Dissolved state

Small portion of CO2 is transported in dissolved state

Only 0.3ml of CO2 is transported in the form ofdissolved CO2 in 100ml of blood


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2)Bound to Hb

CO2 reacts directly with amine radicals of thehemoglobin molecules to form the compound

carbaminohemoglobin (CO2Hgb) This combination of CO2 & hemoglobin is a reversible

reaction that occurs with a loose bond, so that CO2 iseasily released into the alveoli, where the PCO2 is

lower than in the pulmonary capillaries


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3)Bicarbonate ion

In lungs, HCO3- enters in RBC in exchange for chloride.HCO3- recombines with H+ to form H2CO3 ;decomposes intoCO2 and H2O .Thus CO2 generally generate in tissue isexpired.


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4.Regulation of respiration4.Regulation of respiration Respiratory centre is composed of several groups of

neurons, located bilaterally in medulla oblongata andpons of the brain stem

A. Dorsal respiratory group

Located in dorsal part of medulla(nucleus of tractussolitarus)

Mainly cause inspiration

Nucleus of solitarus is sensory termination of vagus

and glossopharyngeal nerve which transmit sensorysignal into respiratory center from peripheralreceptor in lung


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B.Ventral respiratory group Located in ventrolateral part of medulla(nucleus

ambigus)

Causes both inspiration and expiration Pneumatic center

Located dorsally in superior portion of pons

Control rate and depth of breathing


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Fig .Regulation of respiration


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ReferencesReferences Guyton ,C;Hall, J.E: Text book of medical physiology,

11th edition (2007)

Waugh,A; Grant,A; Ross and Wilson anatomy and

physiology in health and illness; ninth edition(2001)


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