Transcript respiratory tract - Pleasantville High School

Human Respiratory
System
Aim: How does your body undergo
respiration?
Function of the Respiratory
System
A. Allows gas exchange between the
external environment and internal
environment.
B. Cilia and mucus membranes line all the
internal walls of the respiratory tract.
C. Works closely with the circulatory
system.
Respiratory
Tract
Structures of the Respiratory
System
A. Nose — air enters through nostrils and
passes into nasal cavity.
1. Air is filtered, warm & moistened.
B. Air moves past the pharynx
(throat) into larynx (voice box)
that contains vocal cords.
Upper Respiratory tract
Structures of the Respiratory
System
C. Trachea (windpipe) — tube that has
cartilage rings.
1. Lined with mucus to trap dust, pollen &
microbes.
2. Tracheal cells have cilia that move trapped
particles towards the pharynx by the beating
cilia.
3. Cartilage rings surround trachea to keep it
open.
Structures of the Respiratory
System
D. Bronchi (two cartilage tubes) — the
trachea splits into the right & left
bronchi, each of which enters the
lungs.
1. Looks like an inverted “Y”.
2. Splits into smaller and smaller tubes called
bronchial tubes.
3. Bronchial tubes subdivide into smaller and
smaller branches called bronchioles.
Structures of the Respiratory
System
E. Bronchioles — small tubes that are
lined with mucus but do not have
cartilage rings.
1. They subdivide and end in alveoli.
Structures of the Respiratory
System
F. Alveoli — also celled air sacs & are the
functional unit of the lungs.
1. Site of gas exchange.
2. One cell layer thick, moist & surrounded by
capillaries.
3. Capillaries transport deoxygenated blood to
the alveoli.
4. CO2 leaves and O2 is picked up.
Alveoli
Structures of the Respiratory
System
G. Lung — made up of the bronchial
tubes, bronchioles & alveoli.
H. Diaphragm — muscle that forms the floor
of the chest cavity.
Gas Exchange
A. After inhalation, high concentration of O2
diffuses into the bloodstream by
capillaries.
B. Hemoglobin in RBC’s carry the O2 as
oxyhemoglobin.
Hb +
O2

HbO2
Hemoglobin
Oxygen
Oxyhemoglobin
Gas Exchange
C. After exhalation, after cellular respiration
cells produce a high concentration of
CO2.
D. Hemoglobin in RBC’s carry the CO2 to
the lungs as a bicarbonate (HCO3).
CO2
+
H2O  HCO3
Carbon dioxide
Water
Bicarbonate
Breathing
 Moves
A.
air into and out of the lungs.
Inhalation:
1. Ribs move up & out.
2. Diaphragm moves down.
3. This increases the volume
of the chest cavity which fills
the lungs with air.
Breathing
B. Exhalation:
1. Ribs move down & in.
2. Diaphragm moves up.
3. This forces air out of
the lung.
Breathing
Breathing
C. Breathing is regulated by the brain
which is sensitive to the concentration
of CO2 in the blood.
D. When CO2 level rises breathing rate
increases.
Disorders of the Respiratory
System
A. Bronchitis — inflammation of the
bronchial tubes.
B. Asthma — allergic reaction characterized
by the constriction of the bronchial tubes
which causes difficulty breathing.
Disorders of the Respiratory
System
C. Emphysema — enlargement &
degeneration of the alveoli which
results in a decreased lung capacity.
Lungs lose elasticity.
D. Pneumonia — alveoli become filled with
fluid & prevents the exchange of
gases.
Disorders of the Respiratory
System
E. Lung Cancer — tumors form in the lung
due to uncontrolled cell division.