Transcript The respiratory system

The respiratory
system
How do you catch your breath?
Respiration
• The exchange of gas from cells to the atmosphere
• common events occur
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Ventilation – the movement of air into or out of the lungs
Gas exchange between blood and and air in lungs
Gas transport in blood between lungs and the body cells
Gas exchange between blood and body cells
The system for all of this
• Function
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Filter particulates from air
Control the air temperature
Control the moisture level of the air
Participate in the sense of smell (the nose)
And helps regulate blood pH
• 2 major regions
– Upper respiratory tract
– Lower respiratory tract
Upper respiratory system
• Nose
– Nostrils – open to the outside world
– Hairs – prevent the entry of large particles
• Nasal cavity
– Hollow space behind the nose
– Nasal septum divides into right and left
– Nasal conchae – bones that curl out of the lateral walls
making passage ways
• Are lined with mucus membranes
– Warms, moistens, and cleans air
Continuing in
• Paranasal sinuses
– The sinuses are air-filled sacs located with in the the skull
bones and open in to the nasal cavity
– Reduce weight of skull and affect the quality of the voice
• Pharynx
– The sorting chamber, sends air to the lungs and food to the
stomach (we hope)
Lower respiratory tract
• Larynx
– Enlargement at top of trachea, bottom of pharynx
– Prevents foreign matter from entering the trachea
– Vocal cords are located here
• 2 pair
– Upper – false vocal cords – helps close off the trachea
– Lower – true vocal cords -this is where all that sound comes from
• Opening between is called the glottis
Continuing down
• Trachea (AKA the wind pipe)
– About 2.5 cm in diameter, and 12.5 cm long
– Also lined with mucus membranes that trap particles as
well as moistens and warms air
– Cilia push the particles back up to the pharynx
• Smokers destroy these hairs and that is how they get smokers
cough
– Has about 20 C-shaped cartilage rings to prevent the
trachea from collapsing
• Open in the back to allow the esophagus to expand
Next up...
• The bronchial tree
– Starts with two main branches – the bronchi (p) bronchus
(s)
• Right and left, they lead to their respective lungs
• Have cartilage rings
– The bronchi divide to smaller and smaller tubes
• Smaller tubes are called bronchioles
• Don't have cartilage rings from here down
– Divide down to terminal bronchioles, then respiratory bronchioles
» End in the alveoli
Where the main work is done
• The alveoli (p) alveolus (s)
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Tiny microscopic air sacs that lie in a capillary network
Made of simple squamous tissue
One cell thick
Location of gas exchange with the blood
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Controlled by diffusion
The lungs themselves
• Have two – right and left
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Hang in the thoracic cavity by the bronchi and some
major blood vessels
• Wrapped in the pleural membranes
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Visceral pleural - attached to lung
Parietal – attaches to the mediasternium and lines
the inner wall of the thoracic cavity
Space between (not significant) called the pleural
space.
A little more about them
• Right lung
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Large of the two
Three lobes
• Left lung
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Two lobes
• Lungs are cone shaped and are soft
Let's breath
• Air moves into and out of the lungs because of air
pressure
• Inspiration AKA inhalation
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Diaphragm lowers (contracts) and the rib cage lifts
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This cause the air pressure in the thoracic cavity to
drop, and air to rush in
• Expiration AKA exhalation
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Diaphragm raises (relaxes) and the rib cage lowers
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This cause the air pressure to increase, and air to
leave
Air Volumes
• Uses a spirometer to measure this
• 4 distinct volumes
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Tidal volume (resting tidal volume)
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The amount of air that enters or leaves during one
respiratory cycle (one in and out)
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Inspiratory reserve volume
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Additional air that enters during a forced inhalation
Expiratory reserve volume
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Resting volume is the normal amount that leaves (about 500
ml of air)
Additional air that leaves during a forced exhalation
Residual volume
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The amount that doesn't leave (about 1200 ml of air)
Capacities
• Respiratory capacities
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Combination of 2 or more volumes
• Vital capacity
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Inspiration reserve + tidal+ expiration reserve
Maximum amount a person can breath out after the
deepest breath possible
• Inspiration capacity
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Tidal volume + inspiration reserve volume
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Maxmium a person can breath in after resting
expiration
Capacities continue
• Functional Residual capacity
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Expiration reserve volume + residual volume
Amount of air that remains in the lungs following a
resting expiration
• Total lung capacity
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Vital capacity + residual volume
About 5800, varies by age and sex
Some disorders
• Emphysema – the destruction/weakening of the
alveoli, severe cases the lungs lose the elasticity, and
can not get air out.
• Asthma – the constriction of the bronchial tubes,
causing less air to reach the alveoli