physiology of nose by dr saima

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PHYSIOLOGY OF NOSE
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PHYSIOLOGICAL FUNCTION OF NOSE

• RESPIRATION?
• Heat exchange
• Humidification
• Filteration
• Nasal resistance
• Nasal fluids and cilliary function
• Voice modification
• OLFACTION

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• HEAT EXCHANGE- Temp of inspired ai can vary from
  -50 degree to 50 degree C and the nose in
  different racial group has modified to suit the
  local ambient temperature.
• Takes place by 3 methods
• Conduction
• Covection
• Radiation

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• HUMIDIFICATION
• Inspiration- despite of the variation in
  temperature of inspired air, the air in post
  nasal space is about 35degree C and is 95
  saturated
• Expiration- Temp of exp air at post nasal sace is
  approx equal to body core temp and is saturated.

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AIR FLOW BERNOULLIS EQUATION

• Velocity of airflow is inversely proportional to
  the cross sectional area of nose
• If change in velocity then pressure will also
  alter. This is reversible described as
• P1/2pv 2 constant
• Airflow VAConstant

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• C.A
• velocity

• NORMAL

• OBSTRUCTED

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• NASAL RESISTANCE
• Half of total airway resistance
• Two resistors in parallel
• Each cavity has a variable resistance value as a
  result of nasal cycle
• Made up of
• Bone, cartilage and the attached muscles
• Mucosa
• The narrowest part of the nose is nasal valve
• It comprises of
• Lower edge of upper lateral cartilages
• Ant end of inferior turbinate
• Adjacent nasal septum and surrounding soft
  tissues
• (AS THE ANT VALVE IS THE NARROWEST PART OF
  AIRWAY, IT IS ONE OF THE MAIN FACTOR IN PROMOTING
  TURBULENT AIRFLOW SINCE IT IS THE LARGEST
  RESISTOR IN THE WHOLE AIRWAY)

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• Nasal resistance is high in infants as they are
  OBLIGATE NOSE BREATHERS at least initially

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• NASAL CYCLE- Cyclical changes that takes
  place in nose every 4-12 hours and consists of
  alternate nasal blockage between passages and is
  unnoticed by majority of people.
• The changes are produced by vascular activity
  particularly by the veins of pseudoerectile
  tissue of the nose(capacitance vessel)
• The cycle has been demonstrated by Rhinomanometry
  and Thermography.
• The physiological significance is uncertain but
  in addition to the resistance and flow cycle, the
  flow of nasal secreation is also cyclical with an
  increase in secreation in the side with greater
  airflow

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FACTORS AFFECTING NASAL RESISTANCE CYCLE

• Exercise
• Sympathomimetics
• Rebreathing
• Atropic rhinitis
• Erect posture

• Infective rhinitis
• Allergic rhinitis
• Vasomotor rhinitis
• Hyperventilation
• Supine posture
• Ingestion of alcohol
• Asaprin
• Sympathatic antagonist
• Cold air

• Factors decreasing nasal resistance

• Factors Increasing nasal resistance

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• FILTERATION-nose is able to remove particles of
  30 micro metre or more from the inspired air.
• This includes most of the poleen particles which
  are among the smallest particles deposited on the
  nasal mucosa and accounts for the nose being
  predominantly affected site in hay fever.
• Other characteristics of smaller particles
  include shape and smoothness.
• Nasal hairs only stops the largest particles to
  get deposited in the nasal mocosa

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• Rhinomanometry -
• Nasal airway assesment
• Type-
• Active passive
• Anterior posterior
• Acoustic
• TNP Directly proportional to air flow

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Rhinomanometry equipment
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Sealing of one nostril with adhesive tape
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Fig- A TRANSPARENT FACE MASK, SIMILAR TO THAT
USED FOR ADMINISTERING GENERAL ANAESTHESIAIS
USED, INCORPORATING A PNEUMOTACHOGRAPH AND
CONNECTED TO AN AMPLIFIER AND A RECORDER
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Fig-Rhinomanometric recording of transnasal
pressure against flow during breathing AT rest
through an unremarkable nose and through an
abstructed nose
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NASAL SECRETION CILLIARY ACTION

• NASAL SECRETIONS Composed of-
• Water and ion from transudation, serous glands)
• Glycoproteins (sialo, sulfo,fucomucin)
• Enzymes ( lysozyme and lactoferrin)
• Circulatory proteins (complement, alpha 2
  macroglobin, C- reactive protein)
• Immunoglobins ( IgA,IgE,IgG,IgM,IgD)
• Cells (surface epith,basophils,eiosinophilsd and
  leucocytes)

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CILIA ULTRASTRUCTURE
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• Beat frequency of cilia is between 10-20 Hz at
  body temp with a mean of 14Hz remains fairly
  constant between 32-40 degree Ac
• Each beat consists of rapid propulsive and
  recovery phase
• Mucous blanket is propelled backwards by
  metachronous movement of cilia much like a
  conveyor Belt from front of nose posteriorly,
  mucous from sinuses join the stream on lateral
  wall of nose?passes mainly through middle meatus
  and then around E.O before being swallowed

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PATTERN OF CILIARY BEAT
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HISTOLOGICAL STRUCTURE
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• MUCUS LAYER?
• 1.INNER AQ/SOL/SEROUS LAYER (CONT,LESS
  VISCOUS,SURROUNDS SHAFT OF CILIA)
• 2.OUTER GEL/SUP. LAYER (DISCONT,HIGH
  VISCOSITY,ALONG TIP OF CILIA,CONTAINS AB,ENZYM)

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• Factors affecting cilliary beat
• Temperature
• Isotonic saline
• PH
• Infection and various drugs

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• VOICE MODIFICATION-Voice is produced by
  modifying the vibrating column of air from the
  larynx. Larynx produces vowel sounds and pitch of
  voice. Fundamental voice frequencies are under
  1000Hz. High frequency sounds , the consonants,
  are added by pharynx,lips, teeth, tongue. Nose
  adds quality to this by allowing some air to pass
  through it.
• Rhinolalia clausia
• Rhinilalia aperta

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REFLEXES

1. AXON REFLEXES
2. REFLEXES FROM NASAL STIMULI
3. NASOPULMONARY REFLEXES
4. REFLEXES ACTING ON NOSE
5. CUTANEOUS STIMULATION

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DRUGS ACTING ON VASCULAR TISSUE OF NOSE

1. SYMPATHOMIMETICS AND THEIR ANTAGONISTS
2. PARASYMPATHOMIMETICS AND THEIR ANTAGONISTS
3. HISTAMINE AND ANTIHISTAMINE
4. LOCAL ANAESTHETICS
5. HORMONES

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THANK YOU