THE RESPIRATORY STRUCTURE BREATHING MECHANISM IN HUMAN AND ANIMALS

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THE RESPIRATORY STRUCTURE BREATHING MECHANISM IN HUMAN AND ANIMALS Powered By Docstoc
					THE RESPIRATORY
STRUCTURE &
BREATHING MECHANISM
IN HUMAN AND ANIMALS
INTRODUCTION

 Movement of the gases between
  respiratory surfaces & external
  surfaces is entirely by diffusion
 The respiratory surfaces are adapted
  for maximum gases exchange by
  increasing the total surface area.
 The larger the respiratory surface area,
  the higher the rate of gas diffusion.
CHARACTERISTIC OF RESPIRATORY
SURFACES OF GASES EXCHANGE

 (a) Large total respiratory surface area
   - branched, folded & numerous in
   quantity
   - Small in size
 (b) Moist Respiratory Surface
   - To facilitate gases diffusion
 (c) Thin wall of respiratory surfaces
   - one cell thick
UNICELLULAR MICROORGANISM
(Amoeba Sp.)
 Very small in size
 The total surface area-volume is large
 Oxygen diffuse into the cell & Carbon
  Dioxide diffuse out of the cell through
  the plasma membrane down the
  concentration gradient
 No special respiratory
structure
INSECTS




          TRACHEAL SYSTEM
TRACHEAL SYSTEM

  Consist of a network of air tubes called
   as tracheae which open to the outside
   through small pores called spiracles.
  10 pairs of spiracles on the thorax and
   abdomen
  Each spiracles is protected by valves
   which control the opening & closing of
   the spiracles.
TRACHEAL SYSTEM

    Each tracheae is supported by chitin rings to
     prevents the air tube from collapsing
    The tracheae branches into finer tubes called
     tracheoles which are in direct contact with
     the insects tissues & organs
    Gases exchange occurs between tracheoles
     & cells by diffusion
    Larger insects such as grasshopper have air
     sacs to speed up the movement of gases to
     & from the insects’ body
The Adaptation of Tracheoles For
Gases Exchange

  Numerous & very fine tracheoles
  Moist tracheoles walls
  Thin epithelial cells of tracheoles
BREATHING MECHANISM OF
INSECTS
 INHALATION:
  The abdominal muscle relax and the
   valve of spiracles open.
  The pressure in trachea decrease
  Air is forced into the body through the
   spiracles.
BREATHING MECHANISM OF
INSECTS
 EXHALATION:
  The abdominal muscle contract
  The pressure in tracheae increase.
  The air is forced out of the body
   through spiracles
FISH
(GILLS)
RESPIRATORY STRUCTURES

  Specialized respiratory structures
   called gills
  4 pairs of gills which are covered by
   operculum
  Each gill is composed of filaments
   which are supported by gill arch
RESPIRATORY STRUCTURES
  The filaments have numerous thin-walled
   lamellae to maximise the surface area for gases
   exchange
  The gill filaments have thin membrane & rich
   supply of blood capillaries to facilitate efficient
   gases exchange
 Efficiency of gases exchange is enhanced
  by the countercurrent exchange
  mechanism
 Water flows over the gills in one direction
  & the blood flows in the opposite direction




    Water flows
 The deoxygenated blood enters the
  capillaries & encounters water with higher
  oxygen concentration
 Different concentration of Oxygen allows
  the transfer of Oxygen into the blood.
BREATHING MECHANISM

 Breathing mechanism of fish is helped by
  ventilation (combination of movement of
  operculum and the floor of the mouth)
 Fish ventilate by swimming and by
  opening & closing the operculum to draws
  water into the mouth & passes the gills
Inhalation (Flows of water into the mouth)
 Mouth open, the floor of mouth is lowered
  caused the volume of buccal cavity increases
 Pressure in the mouth cavity decreases &
  outside increases.
 Higher outside pressure causes the operculum
  close & water enters the mouth
BREATHING MECHANISM
Exhalation (Flows of water through the gills)
 Mouth closes, the floor of mouth is raised
  caused the volume of buccal cavity
  decreases
 Pressure in the mouth cavity increases &
  outside decreases.
 Water flows through the lamellae & gaseous
  exchange occur between the blood capillaries
  & water.
 Operculum open due to higher inside pressure
  & water flows out
BREATHING MECHANISM
AMPHIBIAN

 Amphibian breathe through the skin,
  mouth & lungs.
 In the water, the frog’s skin functions as
  the respiratory surfaces for gaseous
  exchange.
 Adaptation of skin:
  - thin skin
  - moist skin
  - Supplied with many blood capillaries
RESPIRATORY STRUCTURE
OF AMPHIBIAN
RESPIRATORY STRUCTURE
 The lungs consist of a pair of thin-walled sacs
  connected to the mouth through an opening
  called glottis.
 The membranes lungs are thin, moist &
  covered by network capillaries.
 The lungs of frogs are not as efficient as the
  lungs of human because they are not equipped
  with a rib cage @ diaphragm
 However, they have strong muscular walls of
  bucco-pharyngeal floor.
BREATHING MECHANISM

 INHALATION:
  Bucco-pharyngeal walls lowered, glottis
   closed.
  Pressure inside mouth decreases, air is
   forced into the mouth through nostrils.
  Nostril closes & bucco-pharyngeal walls
   raises up& glottis open
  Air passes to the lungs & gaseous
   exchange occurs
BREATHING MECHANISM

 EXHALATION:
  Lungs muscle contract, air is expelled
   from the lungs
  Some of air escapes through the nostrils
  The rest mixes with the air in the bucco-
   pharyngeal cavity
HUMANS RESPIRATORY
SYSTEM
 Consist of nasal cavity,
  pharynx, trachea,
  bronchi, bronchioles &
  lungs
 Air enters through the
  nostrils & passes through
  the pharynx, trachea,
  bronchi, bronchioles &
  end in alveolus
 The trachea is supported by rings of
  cartilage (C-shaped) to prevent the tube
  from collapsing
 The lower end of trachea divides into 2
  tubes called bronchi.
 The bronchi branches repeatedly into
  smaller tubes called bronchioles.
 Each bronchioles ends in a cluster of air
  sacs called alveoli.
 Inner surface of alveoli is lined with a layer
  of moist epithelial cells
 Outer surface of alveoli is covered by a
  network of blood capillaries
BREATHING MECHANISM
 Involves combined
  action of the
  intercostals muscle
  and diaphragm.
 2 sets of intercostals
  muscle:
  - external
  intercostals muscle
  - internal
  intercostals muscle
 Breathing involves the alternate process of
  inhalation & exhalation
 INHALATION:
  - External intercostals muscle contract &
  Internal intercostals muscles relax
  - Rib cage move upwards & outwards
  - Diaphragm contracts & flatten at the same
  time
  - Volume of thoracic cavity increases
  - Higher atmospheric pressure outside causes
  the air to rush in through the nostrils.
   EXHALATION:
    - External intercostals muscle relax &
    Internal intercostals muscles contract
    - Rib cage move downwards & inwards
    - Diaphragm relaxes & curves upward at
    the same time
    - Volume of thoracic cavity decreases
    - Higher pressure in alveoli inside causes
    the air to rush out through the nostrils.

				
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