respiratory system

Respiratory SystemThe Breath of Life

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Mechanism of A Car

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Respiration

- a life process common to both plants & animals.

is an exchange of Oxygen and Carbon dioxide between the atmosphere and the blood and the body’s cells.

4 Respiration Processes

1. Breathing (ventilation) – air in to and out of the lungs.

2. External respiration – gas exchange between air and the blood.

3. Internal respiration – gas exchange between blood and tissues.

4. Cellular respiration – oxygen used to produce ATP, carbon dioxide as waste.

Breathing vs. Respiration

Breathing = Inspiration + Expiration – intake of air/inhale to bring fresh

supply of oxygen.– breathing out of air/exhale to get rid

of CO2

Respiration – process of gas exchange between various body compartments

Process of Breathing: Pressure Gradient


• Inspiration/Expiration: air in/air out• Cycle:

Relaxed State – diaphragm and intercostal muscles relaxed.

Inspiration – diaphragm contracts, pullling muscle down, intercostal muscles contract elevating chest wall and expanding volume of chest lowering pressure in lungs, pulling in air

Expiration – muscles relax, diaphragm resumes dome shape, intercostal muscles allow chest to lower resulting in increase of pressure in chest and expulsion of air.

Respiratory Cycle

Gas Exchange & Transport: A Passive Process

Gases diffuse according to their partial pressures.

External Respiration – gases exchange between air and blood

Internal respiration – gases exchanged with tissue fluids

Oxygen transport – bound to hemoglobin in red blood cells or dissolved in blood plasma

Carbon dioxide transport – dissolved in blood plasma, bound to hemoglobin

Human Respiratory System

Components of the Upper Respiratory Tract

Upper Respiratory Tract Functions

• Passage way for respiration• Receptors for smell• Filters incoming air to filter large

foreign material• Moistens and warms incoming air• Resonating chambers for voice

Lower Respiratory Tract Functions

Larynx – maintains an open airway, routes food and air appropriately, assists in sound production

Trachea – transports air to and from lungs

Bronchi – branch into lungsLungs – transport air to alveoli for gas

exchange

Respiratory Organs

1. Nose- main entrance and exit to the respiratory system. - connected to winding passages that warm, moistened and filter the air as it passes through respiratory tract.- nostrils lined with hairs that filter out dust- mucous membrane that sticks or traps particles

2. Pharynx (FAIR-inks) / Throat- passageway for both food and air- assumes an important function in the formation of sound particularly in the creation of vowel sounds.

It is lined with cilia – hairlike parts that help filter air on its way to the lungs.

Respiratory Organs

3. Larynx (LAIR-inks)/ Voicebox- connects the pharynx with the trachea.- its opening is at the base of the tongue.- supported by nine pieces of cartilages; 3 are single and 3 are paired.

Thyroid cartilage – largest single piece- Adam’s apple

Respiratory Organs

Epiglottis (ep-ih-GLOT-iss)- a large, single leaf-shaped piece of cartilage.- pulls down over the glottis when we swallow to keep food or liquids from getting into the trachea.

Glottis - opening over the true vocal

cords.

Respiratory Organs

Larynx is arranged in 2 pairs of folds:

1. Vestibular Folds/ False Vocal Cords – upper pair, prevent air from exiting

the lungs as when you hold your breath.

2. Vocal folds/ True Vocal Cords- air coming from lungs cause the

vocal cords to vibrate - sound

Respiratory Organs

Pitch - controlled by tension on the true vocal cords.

Tension = Pitch

True vocal cords are thicker in men; vibrate more slowly = lower pitch than that in women

Respiratory Organs

4. Trachea (TRAY-kee-ah) / Windpipe- cylindrical tube about 4.5 inch passageway for air- like pharynx, it is lined with cilia

If foreign object gets caught in the trachea, a cough reflex expels it.

Respiratory Organs

5. Bronchi (BRAHN-kigh)- divided into 2 primary bronchi; left &

right- passageway going through the lungs- branch into smaller branches called

Bronchioles

Respiratory Organs

LungsPleural membrane – encloses and protects each lung- contains lubricating fluid to prevent friction as lungs expand and contract during breathing.

Alveoli

Respiratory Organs

Measurement of Lung Capacity

• Lung Volumes and Vital Capacity

Tidal volume – volume of air inhaled and exhaled in a single breath

Dead space volume – air that remains in the airways and does not participate in gas exchange.

Vital Capacity – the maximal volume that can be exhaled after maximal inhalation

Inspiratory reserve volume – the amount of air that can be inhaled beyond the tidal volume

Measurement of Lung Function

• Lung Volumes and Vital Capacity

Expiratory reserve volume – the amount of air that can be forcibly exhaled beyond the tidal volume

Residual volume – the amount of air remaining in the lungs, even after a forceful maximal expiration

Measurement: spirometer

Measurement of Lung Function

Regulation of Breathing

• Respiratory center in the medulla oblongata

- establishes basic breathing pattern• Chemical receptors

- monitor carbon dioxide, hydrogen ions, and oxygen levels

• Medulla- sensitive to hydrogen ions in

cerebrospinal fluid resulting from carbon dioxide in blood

Regulation of Breathing: Nervous System Involvement

• Carotid and aortic bodies- sensitive to carbon dioxide, pH, and

oxygen levels• Conscious control

– resides in higher brain centers; ability to modify breath is limited

Regulation of Breathing: Nervous System Involvement

1. Cough – is a mechanism for clearing obstruction of the air.

2. Sneeze – described as an upper respiratory cough. More and more air is inspired and the air is expelled with and explosive force.

3. Hiccup – Spasmodic contraction of the diaphragm, resulting from stimulation in the diaphragm itself or in respiratory center of the brain.

4. Yawn – aids respiratory by more completely ventilating the lung.

Respiratory Phenomena

Disorders of Respiratory System

• Reduced air flow: Asthma, Emphysema, Bronchitis

• Infections: pneumonia, tuberculosis, botulism

• Lung Cancer• Congestive Heart Failure• Cystic fibrosis

• Asthma – Respiratory pathways become irritated

and bronchioles constricted• Emphysema

– Alveoli break down, resulting in reduced in surface area needed for gas exchange with alveoli’s blood capillaries

• Bronchitis– Respiratory pathways become infected

resulting in coughing and production of mucus


• Tuberculosis– a specific bacterium infects the lungs –

less elasticity of the capillaries surrounding alveoli

decreasing effective gas exchange bet. air & blood


Pneumonia

- Infection of the lungs causes alveoli to collect mucus material

• Lung Cancer – Uncontrolled cell growth in lung tissue –

persistent cough, shortness of breath, bronchitis or pneumonia and even death.


respiratory system

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