PHYSIOLOGY OF RESPIRATION
I Overview
A. Anatomy review
1. conducting vs respiratory structures
2. pleural membranes and cavity
3. alveolus
a. surface area
b. respiratory membrane
1. Ficks Law
c. elastic fibers
d. Type II alveolar cells: surfactant
e. macrophages: trypsin
f. pores of Kohn
B. Processes
1. pulmonary ventilation (bulk flow)
2. external respiration (diffusion)
3. internal respiration (diffusion)
4. cellular respiration
When you have finished this unit you should be able to:
- identify the structures of the respiratory system, passageways, pleural membranes, pleural cavity, and alveolar structure
- describe the structure of the respiratory membrane
- explain the advantages of respiratory membrane structure, according to Fick's law
- distinguish between pulmonary ventilation, external respiration, internal respiration, and cell respiration
II Pulmonary Ventilation
A. Air Flow, F = rP/R
B. Pressure gradients
1. atmospheric
2. intra-alveolar
3. Boyle’s Law: pressure-volume relationship
a. changing thoracic volume: respiratory muscles
1. resting ventilation
2. active ventilation
4. lung to thoracic wall
a. pleural membranes
b. transmural pressure (gradient between intra-alveolar and intra-pleural pressure)
c. pneumothorax ---> atelectasis
C. Resistance
1. airway diameter
2. compliance
a. elasticity
b. surface tension (inside alveolus)
1. surfactant (surface active agent)
When you have finished this unit you should be able to:
- interpret the formula for air flow, F = rP/R
- explain what is meant by atmospheric pressure
- state Boyle's Law
- explain how volume and pressure affect air flow into and out of the lungs
- list specific muscles in resting inhalation and describe how they effect thoracic volume
- list specific muscles in resting exhalation and describe how they effect thoracic volume
- list specific muscles in active inhalation and describe how they effect thoracic volume
- list specific muscles in active exhalation and describe how they effect thoracic volume
- describe the relationship between intra-alveolar, intra-pleural, and transmural pressure
- explain why changing the volume of thoracic cavity also changes the volume of the lungs
- explain the pressure changes which cause atelectasis
- list the general causes of resistance in pulmonary ventilation
- define compliance and state its effects on inhalation
- list factors which affect compliance
- define surface tension and explain how surfactant affects surface tension
- discuss the effects of surface tension on inhalation and exhalation
D. Terminology
1. volume + volume = capacity
2. hypoventilation
3. hyperventilation
4. hyperpnea
5. dyspnea, apnea, eupnea
E. Lung disease
1. obstructive
a. narrowed passages: smooth muscle contraction, mucus
b. asthma, chronic bronchitis, emphysema
c. i FEV1
2. restrictive
a. damaged lung tissue, decreased surface area: scar tissue
1. alpha anti-trypsin
b. pulmonary fibrosis, emphysema
c. i vital capacity
F. Regulation of Pulmonary Ventilation
1. neural
a. medullary areas
1. inspiratory (rhythmicity) center
2. expiratory center
b. pons centers - influence medullary centers; fine-tune breathing transitions
1. apneustic center
2. pneumotaxic center
c. cortex - conscious control
D. hypothalamus and limbic system - emotional regulation
2. chemical
a. [H+]
b. [CO2]
c. [O2]
d. receptors
1. central chemoreceptors
2. aortic bodies, carotid bodies
3. mechanical
lung volume practice for respiration laboratory
When you have finished this unit you should be able to:
- distinguish respiratory volumes from respiratory capacities
- compare and contrast hypoventilation, hyperventilation, and hyperpnea
- define apnea, dyspnea, eupnea
- compare obstructive and restrictive lung disease: causes, diagnostic tests
- discuss emphysema causes and diagnostic tests
- list the different regions of the brain involved in ventilation and explain the general type of regulation done by each area
- list the respiratory centers in the brainstem and the role of each center
- describe the location and role of the central chemoreceptors (note location of other chemoreceptors)
- describe the effect that blood levels of [H+], [CO2], and [O2] have on these centers
- explain why these centers are less sensitive to drops in blood [O2] levels
- explain the connection between [CO2] levels and pH levels in the blood (include the reaction of CO2 with H20)
- describe the Hering-Breuer reflex and why it is a protective reflex
III External Respiration and Internal Respiration
A. Partial pressures
1. Dalton's Law
a. altitude effects
B. Hemoglobin
1. loading reaction: deoxyhemoglobin + O2 ---------------> oxyhemoglobin
lungs
2. unloading reaction: deoxyhemoglobin + O2 <------------ oxyhemoglobin
tissues
a. oxyhemoglobin dissociation curve: % of oxyhemoglobin and the partial pressure of oxygen
b. affinity of oxygen for hemoglobin is decreased in low pH conditions; Bohr effect
c. affinity of oxygen for hemoglobin is decreased in higher temperatures
When you have finished this unit you should be able to:
- explain what partial pressure means
- state Dalton's Law
- describe the effect of high altitude or below sea level on the partial pressure of oxygen
- write a simple equation for hemoglobin laoding and unloading reactions
- state the effect of lower partial pressure of oxygen on the amount of oxygen bound to hemoglobin
- state the effect of pH on the affinity between oxygen and hemoglobin, relate this to conditions in the body
- state the effect of temperature on the affinity between oxygen and hemoglobin, relate this to conditions in the body
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