Transcript Respiratory System

Respiratory System
Breathe in. Breathe out.
Any questions?
Outline
• Functions of the respiratory system
• Organs of the respiratory system
• Process of breathing
Functions of the respiratory system
Functions of the respiratory system
1) Fill and empty the lungs
2) Oxygenate and remove CO2 from blood
3) Oxygenate and remove CO2 from tissues
Functions of the respiratory system
1) Fill and empty the lungs
Ventilation
2) Oxygenate and remove CO2 from blood
External respiration
3) Oxygenate and remove CO2 from tissues
Internal respiration
Organs of the respiratory system
Organs of the respiratory system
The Airway
Organs of the respiratory system
The Airway
• Other organs
(Not the airway)
Organs of the respiratory system
The Airway
• Nasopharynx
• Larynx
• Trachea
• Bronchi
• Lungs
Upper Respiratory tract
Lower Respiratory tract
Organs of the respiratory system
The Airway
• Nasopharynx
• Larynx
• Trachea
• Bronchi
• Lungs
• Other organs
(Not the airway)
Organs of the respiratory system
The Airway
• Nasopharynx
• Larynx
• Trachea
• Bronchi
• Lungs
• Other organs
(Not the airway)
• Oral pharynx
• Vocal cords
• Epiglottis
• Ribs / intercostal mm.
• Diaphragm
• Pleura
The Airway--Nasopharynx
• The nose is the primary airway,
(connected to oropharynx as backup airway)
• Nasal cavity warms & filters inspired air
– Nasal conchae allow air to pass over blood
supply to warm it
– Vibrissae (nose hair) and mucus trap dust
• Important in smell, voice
The Airway--Larynx
• AKA--voice box
• Contains vocal cords, vibrate against
each other to produce sound—requires
skeletal muscle contraction
• Covered by epiglottis during swallowing
to separate GI tract from airway.
• More prominent in men (Adam’s apple)
The Airway--Trachea
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AKA—windpipe
Below larynx.
Splits into two bronchi
Has C-shaped rings of cartilage for structure
– Otherwise, it would collapse as you inhale.
– Rings are open at back to allow for expansion.
The Airway--Bronchi
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Smaller than trachea
Still has rings of cartilage
One leads to left lung, the other to the right.
Lined with ciliated pseudo-stratified
columnar ET
– epithelia makes mucus
– Cilia move mucus upwards- to be coughed out
The Airway--Lungs
• Bronchi split into lobar bronchi
– Three on the right, two on the left
• Lobar bronchi split into bronchioles
– Smooth muscle can constrict them
• Bronchioles split smaller and smaller
 alveoli
Process of breathing
• We use a negative pressure system
• To breathe in: lift ribs, lower diaphragm,
open airway, and air rushes in to fill the
space provided in the lungs.
• To breath out: relax. The elasticity of the
lungs will push out (enough) air
Process of breathing
• We use Inspiration
a negative pressure system
• To breathe in: lift ribs, lower diaphragm,
open airway, and air rushes Together:
in to fill the
space provided in the lungs.
Respiration
• To breath out: relax. The elasticity of the
lungs will push out (enough) air
Expiration
Pressure
• Pressure differences allowing inspiration
and expiration are only ~1/150 atm.
• Using breathing muscles with the airway
closed can change pressure more, forcing
blood into and out of the chest
The lungs—as organs
• One lung on each side, two lobes on the
left lung, three on the right
• One can be surgically removed (or
individual lobes)
• In the thoracic cavity—protected by ribs,
sternum, spine, shoulder blades
• Covered by pleura
Pleura
• Two layers of pleura—parietal & visceral.
• The space between them has fluid for
lubrication
Pleura
• Two layers of pleura—parietal & visceral.
Lining
chest wall
Lining lung
surface
• The space between them has fluid for
lubrication
Control of breathing
Respiratory center: in brain stem (pons/medulla)
Pneumotaxic area controls breathing rate
Breathing volume=breathing rate x inflation
Control of breathing
• Normally:
12 breaths/min. x .5 L /breath=6 L/min.
(can increase to 200 L / min. in emergency)
Volumes
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Tidal volume (TV)
about .5 L
Inspiratory reserve (IR) about 2.5L
Inspiratory capacity (IC)
(=TV+IR)
Expiratory reserve(ER) about 1.5L
Expiratory capacity (EC)
(=TV+ER)
Vital capacity (VC)
(=TV+IR+ER)
Residual volume (RV) about 1.5 L
Control of breathing
CO2 sensors —(pH of blood)higher
breathing rate when pH falls
– In respiratory center
O2 sensors —(not as effective)  increase
breathing rate & volume when O2 is low
– In major arteries
Remember how the blood carries
gasses?
• O2 is bonded to hemoglobin in RBC
• CO2 can be bonded to hemoglobin, but is
usually dissolved in plasma.
Acidity and CO2
• H2O + CO2  H2CO3 (carbonic acid)
• pH falls as CO2 dissolves in blood
• pH rises as CO2 leaves blood
• Low pH makes it easier for RBC’s to give
up O2.
Branching of
the airway
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Trachea
Bronchi
Lobar bronchi
Bronchioles
Alveoli
Structure of an alveolus
Gas exchange
• Alveoli are very thin (simple squamous ET)
• Filled with inspired air (mixed with unexhaled air already in the lungs)
Gas exchange
• Capillaries have the thinnest possible ET
(simple squamous)
• CO2 leaves blood, enters alveolar air
• O2 leaves alveolar air, enters blood
(By diffusion)
Gas exchange in tissues
• Cells in the tissues use O2 and make CO2
• Capillaries have the thinnest possible ET
(simple squamous)
• O2 leaves blood, enters interstitial fluid
• CO2 leaves interstitial fluid, enters blood
(By diffusion)
Respiratory pathology
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Pneumothorax •
Cancer
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Emphysema •
Punctured lung•
Hiccups
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Hyper•
ventilation
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• Cystic fibrosis •
Coughing
Pneumonia
Bronchitis
Asthma
Pleurisy
Cold
Influenza
Asphyxia
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Strep throat
COPD
Asbestosis
Pulmonary
Edema
• Sinusitis
• Anoxia
• Nosebleeds