Ch. 16: Respiratory Physiology

Name a few organs?? the respiratory system consists of

- Oral and nasal cavities
- Lungs (tubes that lead to lungs)
- Chest Structures

Two actions of the respiratory system (intake and out take of what?)

- Intakes O2 for delivery to the blood
- Eliminates CO2 from the blood

What is Ventilation?

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

What is Gas Exchange?

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

What is Oxygen Utilization?

Use of oxygen in cell respiration

Name the 6 parts in the respiratory system

- Nose/Mouth
- Pharynx (throat)
- Larynx (voicebox)
- Trachea (windpipe)
- Bronchus
- Lung

Name and state the order of the parts within the Lungs:

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

What are the three parts within the Upper Airways?

- Nose/mouth
- Pharynx
- Larynx

What's within the conducting zone?

All structures through which air passes before reaching the respiratory zone

3 actions of the conducting zone

- CONDUCTS air to the respiratory zone
- warms and humidifies inspired air
- filters and cleans air

What is the Respiratory Zone?

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

(think *respiratory zone COMPRISES respiratory bronchioles)

The _______ zone transports air to the ______ zone

conducting; respiratory

How many alveolar sacs does most gas exchange occur in?

8 million

______ and ______ have rings of cartilage

trachea; bronchi

What are bronchioles surrounded by?

Smooth muscle

What determines how easily airflow can occur?

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

Where is the intrapleural space (pleural cavity) located?

Between the parietal and visceral pleura (epithelial membrane)

think *VIP:
- V.isceral
- I.ntrapleural
- P. Parietal

What does intrapleural space contain?

A thin layer of fluid that acts a lubricant

What are the 4 protective mechanisms?

1. Nasal hairs/Mucus
2. Mucus escalator
3. Bronchoconstriction
4. Macrophages

Nasal hairs and mucus...

trap particles

Mucus escalator...

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

Bronchoconstriction

- responds to irritation
- prevents particulate matter from entering alveoli

Macrophages

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

*protections us from infections

Air _____ moves from ___ pressure region to ____ pressure region

passively; high; low

What is the movement determined by? (continuing from last question)

Intra-alveolar and atmospheric pressures

Intra-alveolar Pressure = ? = ?

Palv = pressure inside lungs

Atmospheric Pressure = ? = ?

Patm = 760 mmHg at sea level

If Palv < Patm, what occurs?

Inspiration (air moves into lungs where pressure is lower)

If Palv > Patm, what occurs?

Expiration (air moves out of lungs)

*think expiration = exhalation

What determines the pressure in lungs?

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

Increase lung volume ______ Palv, resulting in ______

reduces; inspiration

Decreased lung volume _______ Palv, resulting in _____

increases; expiration

What is inspiration?

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

What occurs during inspiration?

- Parasternal & external intercostals contracts
- Diaphragm contracts and is lowered
- Lung volume increases which decreases Palv

What is expiration?

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

What occurs during expiration?

- Inspiration muscles relaxes
- Diaphragm relaxes
- Lung volume decreases

Tidal Volume:

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

Inspiratory/Expiratory reserve volumes:

The additional volume that can be inspired or expired

The Tidal Volume, Inspiratory and Expiratory quantities sum to the lung's ______.

Vital capacity

Residual Volume

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

What is alveoli?

Clusters of epithelium-lined air sacs

What does each clustered alveoli include in regards to blood vessels?

An abundance of pulmonary capillaries

Why does aveoli having pulmonary capillaries so important... what does it allow?

- It assures that the ventilated air is within range to the "pulmonary" blood
- It allows efficient gas exchange between the air and the body

Type 1 alveolar cells:

form most of the epithelium

Type 2 Alveolar Cells:

secrete a detergent-like substance called surfactant

What does surfactant do?

Decreases surface tension in alveoli to prevent alveolar collapse

Partial Pressure

pressure of each individual gas

Oxygen from alveoli...

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

Carbon dioxide from the cell...

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

In regards to partial pressures of gases, what occurs in the lungs?

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

State what happens during Neural Control of Respiration

Motor neurons cyclically stimulate skeletal muscle contraction/relaxtion

What chemoreceptors are in the Chemical Control of Respiration?

- Peripheral chemoreceptors in heart
- Central chemoreceptors in medulla oblongata of brain

What is the main function for chemical control of respiration?

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

What serves as a buffer for H+?

Bicrabonate (HCO3-)

Hypoventilation =

Dcecrease/Inadequate ventilation

Hyperventilation =

Increased ventilation

What occurs during HYPOventilation?

- PCO2 increases
- reaction proceeds to the right, pH decreases

What occurs during HYPERventilation?

- PCO2 decreases
- reaction proceeds to left, pH increases

What causes PCO2 to increase in the cells of the body?

Metabolic processes in the cells

What "informs" the respiratory center to increase the rate of ventilation?

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

How much mL of O2 does blood carry?

20 mL of O2 per 100 mL of blood

State the percentages of blood in regards to O2 Transport in blood

- 1.5% is dissolved as a gas in plasma and RBCs
- 98.5% is bound to hemoglobin in RBCs

Hemoglobin molecule:

4 globins bound to 4 hemes

What is in the center of each heme

One atom of iron that can combine with one O2 molecule

Where does the loading and unloading of O2 occur?

Loading = pulmonary capillaries
unloading = Systemic capillaries

State the percentages in regards to CO2 transport in blood?

- 10% dissolved as a gas in plasma and RBCs
- 20% as a carbaminohemoglobin
- 70% is tranported as HC03-

What happens to ventilation during exercise?

- 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