Notes Pt 2 - Respiratory Physiology

Notes Pt 2 - Respiratory Physiology

Respiratory events

I. Respiration consists of 4 distinct events. Describe each.

A. pulmonary ventilation

B. external respiration

C. respiratory gas transport (discussed in blood chap)

D. internal respiration

II. define cellular respiration

Pulmonary ventilation: event #1

I. pulmonary ventilation depends on ______.

A. inspiration

B. expiration

II. Pressure relationships in the thoracic cavity

A. intrapulmonary pressure - pressure within ______

1. changes with phases of breathing

2. always equalizes itself with ______

B. intrapleural pressure - pressure within ______

1. also fluctuates with breathing

2. always about ______less than intrapulmonary pressure

3. any condition that causes these 2 pressures to equalize causes immediate

lung collapse

a. atelectasis

b. pneumothorax

C. Boyle’s law : law: Pressure and Volume have an ______relationship

® Inspiration

1. main inspiratory muscles - ______

2. thoracic dimensions change during inspiration to increase volume of thoracic

cavity by ______

3. intrapulmonary pressure drops and air rushes in for normal

quiet inspiration

4. deep (forced) inspiration – requires activation of ______

® Expiration

1. passive process dependent on ______

2. lungs recoil when inspiration stops – so alveoli compress –which leads to a volume

decreases -causing intrapulmonary pressure to rise - gas outflows to equalize

3. forced expiration - contraction of ______

E. D. What Doctors listen for and what the sounds mean:

a. bronchial sounds vs. vesicular breathing sounds

b. wheezing vs. rales

E. Physical Factors influencing the process of Pulmonary Ventilation

a. Respiratory passage diameter - (AKA: resistance due to increased friction of air on

respiratory structures will diminish air flow)

1. smooth muscle ______constriction

2. local accumulations of mucus, infectious material, tumors

b. Lung compliance - the ease with which lungs can readily ______

1. elasticity of lungs & thoracic cage can diminished by 2 factors:

c. Lung elasticity – ability of lung tissue to ______ after expansion

1. essential for normal expiration

2. Emphysema – loss of elasticity causes enormous effort to exhale – at end stages,

alveoli rupture losing surface area for gas exchange

d. Alveolar Surface Tension Forces

1. Surface tension is caused by the tendency of ______molecules such as water to stick to each other with hydrogen bonds – this can cause the walls of the alveoli to stick together like plastic wrap every time you exhale.

a. Large amounts of energy /effort will be required to simply re-expand the lungs

and allow you to inhale

2. surfactant - interferes with ______of water molecules so less energy

needed to expand lungs – this is one of the things that keeps our lungs partially

expanded at all times. (the other thing is the pressure difference previously

discussed)

3. IRDS

End of Quiz #2 Material

Internal & External Respiration: Gas Exchanges in the Body: Event #2 & 4

I. Basic properties of gases

A. Dalton’s law:

1. Dalton's law of partial pressures is used to determine the individual pressures of each gas in a mixture of gases.

2. Gas exchanges that occur between the blood and the alveoli AND between the blood and the tissue cells take place by simple ______and depend on partial pressure gradients of oxygen and carbon dioxide that exist on opposite sides of the exchange membrane.

3. Always moving from ______pressures

B. Henry's law: Deals with gases dissolving into liquids (works together with

Dalton’s law of partial pressures)

1. states that the solubility of a gas in a liquid is directly proportional to the pressure of

that gas above the surface of the solution (IOW: the higher the pressure of the

gas, the more gas will be shoved into the liquid thus increasing solubility)

2. Solubility and partial pressure have a ______relationship

3. The solubility coefficient of the gas also affects this process – the higher the #, the

more the gas “likes” to dissolve into a liquid (based on molecular structure, etc.)

4. Each gas will dissolve in a liquid in proportion to the ______between its

partial pressure gradient and its solubility coefficient

C.2nd Law of Thermodynamics: solubility and temperature have an

______relationship.

The reason for this gas solubility relationship: Increased temperature causes an increase in ______energy. The higher kinetic energy causes more motion in molecules which break intermolecular bonds and escape from solution and vice versa.

II. Factors influencing external and internal respiration

A. partial pressure gradients and gas solubilities

a. oxygen - low solubility but steep partial pressure gradient (64mm Hg)

b. carbon dioxide – higher solubility (20x that of oxygen) but partial pressure gradient only 5mm Hg

c. due to the ratios of solubility coefficients and pressure gradients – ______amounts of gases are exchanged

B. thickness of respiratory membrane

1. Ideal thickness: 0.5 - 1 micrometer (0.000001 meter)

2. Edematous tissue can be caused by congestion and pneumonia – thick tissue hinders

diffusion leading to ______

C. surface area

1. Ideal surface area: 50-70 square meters for gas exchange

2. Disorders such as emphysema or cancer can diminish ______for gas exchange.

Control of Respiration

A. The two nerves that transmit to the respiratory muscles are the ______and ______nerves.

B. The neural centers that control respiration rate & depth are located in the ______& ______. Some terms that deal with respiration rates are:

1. eupnea

2. hyperpnea

3. apnea

4. dyspnea

C. Physical factors, conscious control, emotional factors, and chemical factors all influence respiration rate & depth.

1. hyperventilation

a. Define:

b. Does this cause respiratory acidosis or respiratory alkalosis?

c. Explain using the equation: CO2 + H20 H2CO3 (carbonic acid)

d. What is the treatment for this? Explain why this works using the above equation.

2. hypoventilation

a. Define:

b. Does this cause respiratory acidosis or respiratory alkalosis?

c. Explain using the equation: CO2 + H20 H2CO3 (carbonic acid)

d. What usually causes hypoventilation?

Respiratory Imbalances

A. COPD: Chronic Obstructive Pulmonary Disorder: a group of disorders that block airflow

and make breathing difficult

1.chronic bronchitis

2. emphysema

3. features in common

B. Lung cancer

1. info

2. 3 types: Be able to ID according to appearance & location

3. treatments

C. Cystic Fibrosis

D. SIDS

E. Asthma

Hyperbaric conditions

1. Hyperbaric oxygen chambers - force greater amount of oxygen into patient's blood to treat ______

______

2. How hyperbaric treatment works – explain using gas laws

3. Conditions that can be treated with hyperbaric medicine:

Scuba Diving:

1. What happens in the body as you go down in depth?

2. What happens in the body as you come up at the correct rate?

3. What happens in the body if you come up too fast?

4. Discuss nitrogen narcosis and decompression sickness.

High Altitudes:

1. Why is breathing difficult at high altitudes?

2. What kinds of problems can altitude sickness cause?

3. How does the body adjust given time?

Developmental aspects

A. ______weeks gestation - resp. system sufficiently developed to allow baby to survive – surfactant production not up to speed yet

B. lung development and alveoli formation are not completed until young adulthood

smoking during early teens leads to permanent incomplete lung maturation and

inadequate alveoli formation (Just another reason NOT to smoke!)

C. 70 years of age - vital capacity decreases by 1/3 and can leads to sleep apnea and hypoxia

protective mechanisms become less efficient