Ch. 16: Respiratory Physiology

• Oral and nasal cavities

• Lungs (tubes that lead to lungs)

• Chest Structures

• Intakes O2 for delivery to the blood

• Eliminates CO2 from the blood

Mechanical process that moves air into and out of lungs (think *air vent)

Exchange of gases between the air and blood in the lungs, and between blood and other tissues of the body

Use of oxygen in cell respiration

• Nose/Mouth

• Pharynx (throat)

• Larynx (voicebox)

• Trachea (windpipe)

• Bronchus

• Lung

Left/Right Primary bronchi -----> bronchioles -----> terminal bronchioles -----> respiratory bronchioles -----> alveolar ducts ----- alveolar sacs

• Nose/mouth

• Pharynx

• Larynx

All structures through which air passes before reaching the respiratory zone

• CONDUCTS air to the respiratory zone

• warms and humidifies inspired air

• filters and cleans air

Region where gas exchange occurs, comprising the respiratory bronchioles and alveolar sacs

(think *respiratory zone COMPRISES respiratory bronchioles)

conducting; respiratory

8 million

trachea; bronchi

Smooth muscle

The relaxation/contraction of smooth muscle lining the airways (bronchodilation vs. bronchoconstriction)

Between the parietal and visceral pleura (epithelial membrane)

think *VIP:

• V.isceral

• I.ntrapleural

• P. Parietal

A thin layer of fluid that acts a lubricant

1. Nasal hairs/Mucus

2. Mucus escalator

3. Bronchoconstriction

4. Macrophages

trap particles

keeps lungs clear (ciliated cells in airways carry mucus and particulate matter into the pharynx to be swallowed)

• responds to irritation

• prevents particulate matter from entering alveoli

• (WBCs) in airways and alveoli engulf/destroy inhaled particles and bacteria

*protections us from infections

passively; high; low

Intra-alveolar and atmospheric pressures

Palv = pressure inside lungs

Patm = 760 mmHg at sea level

Inspiration (air moves into lungs where pressure is lower)

Expiration (air moves out of lungs)

*think expiration = exhalation

• Volume of lungs (Boyle's Law: P1V1 = P2V2)

reduces; inspiration

increases; expiration

Movement of air from external environment through airways into alveoli during breathing; inhalation

• Parasternal & external intercostals contracts

• Diaphragm contracts and is lowered

• Lung volume increases which decreases Palv

Movement of air from the alveoli to the external environment during breathing; exhalation

• Inspiration muscles relaxes

• Diaphragm relaxes

• Lung volume decreases

The amount of air moved in or out of the airways in a single breathing cycle

The additional volume that can be inspired or expired

Vital capacity

The amount of air that must remain in the lungs to prevent alveolar collapse

Clusters of epithelium-lined air sacs

An abundance of pulmonary capillaries

• It assures that the ventilated air is within range to the "pulmonary" blood

• It allows efficient gas exchange between the air and the body

form most of the epithelium

secrete a detergent-like substance called surfactant

Decreases surface tension in alveoli to prevent alveolar collapse

pressure of each individual gas

moves into capillaries -----> transports to tissues -----> enters ISF -----> enters cell

enters ISF ---> then capillaries ---> transports to alveoli by the bloodstream

The concentration gradients favors inward (toward blood) diffusion of oxygen and the outward (toward alveolar air) diffusion of carbon dioxide

Motor neurons cyclically stimulate skeletal muscle contraction/relaxtion

• Peripheral chemoreceptors in heart

• Central chemoreceptors in medulla oblongata of brain

detects changes in PO2, PCO2, [H+] to keep them constant

Bicrabonate (HCO3-)

Dcecrease/Inadequate ventilation

Increased ventilation

• PCO2 increases

• reaction proceeds to the right, pH decreases

• PCO2 decreases

• reaction proceeds to left, pH increases

Metabolic processes in the cells

Chemoreceptors that responds to increased carbon dioxide levels in the blood and resulting decreased pH

20 mL of O2 per 100 mL of blood

• 1.5% is dissolved as a gas in plasma and RBCs

• 98.5% is bound to hemoglobin in RBCs

4 globins bound to 4 hemes

One atom of iron that can combine with one O2 molecule

Loading = pulmonary capillaries unloading = Systemic capillaries

• 10% dissolved as a gas in plasma and RBCs

• 20% as a carbaminohemoglobin

• 70% is tranported as HC03-

• Increases to keep up w/ increased metabolism so oxygen, carbon dioxide and pH remain constant

• Increase O2 delivery to skeletal muscles

• PCO2 decreases while pH increases