A. Supply body cells with oxygen.
B Rid body cells of carbon dioxide.
C. Help regulate blood pH.
click
on this image for an audio message II. Respiratory Organs
A. The Conducting organs
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I. Primary functions
A. Supply body cells with oxygen.
B Rid body cells of carbon dioxide.
C. Help regulate blood pH.
click
on this image for an audio message
II. Respiratory Organs
A. The Conducting organs
- Conduits for air to and from the sites of gas exchange.
- Lined by respiratory epithelium (cilated columnar epithelium with goblet cells)
that produces and moves mucus conveyor belt to warm, cleanse and humidify inspired
air.
-Some conduits kept open by surrounding hyaline cartilage.
1. Nose and nasal cavity (tip of nose is cartilage)
2. Paranasal Sinuses (open areas in maxillae, frontal, ethmoid and sphenoid
bones)
3. Pharynx (receives air from nasal cavity, food/water from oral cavity)
4. Larynx (cylinder of cartilage at top of trachea), epiglottis prevents inspiring
food and water, voice cords provides vocalization
5. Trachea (cartilage and respiratory epithelium tube to carry air to/from bronchii)
6. Bronchii (cartilage and respiratory epithelium tube to carry air to/from
bronchioles in lung)
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on this image for an audio message
B. Regulating organ
Bronchiole (found only in lung)
cuboidal epithelium lines lumen, smooth muscle regulates air flow (much like
arteriole regulates blood flow)
C. Gas exchange structure
Alveolus found only in lung)
Simple squamous epithelium, thin layers allows oxygen to enter blood, and carbon
dioxide to leave blood
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on this image for an audio message
D. Lung (lobed organ in which bronchii enter)
Found in pleural cavity which is surrounded by pleural serous membrane (visceral
pleura surroungs lung tissue, parietal pleura covers rib cage)
III. Mechanics of Breathing: pulmonary ventilation
- It depends on volume and pressure changes in the
lungs (alveolus) and pleural cavity.
- Gases move along pressure gradients.
As volume goes up, pressure drops.
A. Inspiration/Inhalation:
Air rushes in.
1) Diaphragm contracts – flattens out.PRIMARY breathing muscle.
2) External intercostals help– lifts rib cage and pulls sternum forward.
3) Both actions increase volume and air rushes into lungs
B. Expiration/Exhalation:
Air rushes out.
1) Diaphragm relaxes – bowed position.
2) External intercostals relax.
3) Rib cage descends with decreasing volume.
4) Lungs recoil or collapse so air rushes out of lungs.
click
on this image for an audio message
Helpful
web link
Another helpful
web link
A
web activity
Another
web activity
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Professor Thomas M. Lancraft
Human Anatomy Courses
at St. Petersburg College
St. Petersburg/Gibbs Campus
6/2006