antomy n phy
TRANSCRIPT
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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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