Transcript THE RESPIRATORY SYSTEM

THE RESPIRATORY
SYSTEM
Respiratory System
Transports gases
between external
environment and the
internal gas exchange
surfaces
Nasal Cavity
Exposed to the air
through nostrils
Is lined with ciliated
mucous membranes,
which filter, warms
and moistens the air
Pharynx
Throat cavity where
oral cavity and nasal
cavity meet
Food is prevented
from entering the
trachea by the
epiglottis
Larynx
Is the voice box
Made mostly of cartilage
Vocals cords are located
here (2 pr of membranes
that are stretched across
the inside of the larynx)
As air is breathed in and
out the cords vibrate to
make sounds
Trachea
Tube lined with rings
of cartilage (for
strength and support)
Lined with ciliated
mucous membranes
for trapping
microscopic particles
Bronchi
Tube which enters
each lung
Extends into each
lung where it
subdivides many
times forming
bronchioles
Alveoli
Bronchioles end with
alveoli
Alveoli are small,
moist, cuplike cavities
which are surrounded
by capillaries
This is where the
exchange of oxygen
and carbon dioxide
takes place
Oxygen is carried by
the red blood cells as
oxyhemoglobin
The oxygen easily
diffuses across cell
membranes to be
used during aerobic
cellular respiration
Carbon dioxide in the plasma is carried in
the form of the bicarbonate ion
CO2 + H2O ----- H2CO3
---------
Diaphragm
A sheet of muscle
which changes the
size of the chest
cavity
Mechanics of Breathing
Mechanical process
of taking air into and
out of the lungs
Inhalation
Air moves into the
lungs
The diaphragm
moves down
The volume of the
chest cavity increases
Pressure decreases
and air moves in
Exhalation
Air moves out of the
lungs
The diaphragm
moves up
The volume of the
chest cavity
decreases
Pressure increases
so air is forced out
Medulla
Lower back part of
the brain that
regulates the
breathing rate
Breathing rate
depends on the
carbon dioxide level
of the blood
Works as a feedback
mechanism to help
maintain homeostasis