the respiratory system 1.nasal cavity a. review of structure and function a.mucous membrane...

The Respiratory System

1. Nasal cavity

A. Review of structure and function

a. Mucous membrane

b. Turbinate bones

c. Blood supply

d. Functions

i. Warm, moisten, filter inspired air

ii. Olfaction

The Respiratory System

2. Pharynx

3. Larynx

4. Trachea

A. Review of structure and function

a. Ciliated mucous membrane

b. Cartilages

The Respiratory System

5. Bronchi and bronchial tree

A. Review of structure and function

a. Primary, secondary, tertiary

b. Bronchioles

i. Terminal

ii. Respiratory

a. Respiratory membrane

b. Surfactant vs. surface tension

c. What is compliance?

6. Alveoli

The Respiratory System

7. Lungs

A. Review of structure and function

a. Apex vs. base

b. Lobes

c. Bronchopulmonary segment

d. Pleura

i. Visceral layer

ii. Parietal layer

iii. Pleural space

iv. Pleural fluid

The Respiratory System

8. Pulmonary ventilation

A. Review of structure and function

a. Inspiratory cycle

i. Active process at rest

ii. Inspiratory muscles

iii. Forced inspiration

b. Expiratory cycle

i. Passive process at rest

ii. Forced expiration and expiratory muscles

The Respiratory System

9. Pulmonary volumes and capacities

A. Review of structure and function

a. Tidal volume

b. Inspiratory reserve volume

c. Expiratory reserve volume

d. Residual volume

e. Vital capacity

f. Total lung capacity

SPIROGRAM

IRV

ERV

TV

RVmaximum expiration

VC TLC

6000 ml

5000 ml

4000 ml

3000 ml

2000 ml

1000 ml

maximum inspiration

The Respiratory System

9. Pulmonary volumes and capacities

A. Review of structure and function

g. Clinical values of importance

i. Maximum breathing capacity

ii. Minute respiratory volume

iii. Forced vital capacity

iv. Forced vital capacity per second (FEV1)

The Respiratory System

1. Trachea and bronchi

B. Age-related changes

a. Calcification of cartilages

b. Smooth muscle in bronchioles replaced by collagen

c. Loss of elasticity of lungs and thoracic wall (decreased compliance) decreased maximum breathing capacity and vital capacity

i. Age 25, MBC = 165L/min; age 85, MBC = 75L/min

ii. Age 25, VC = 100%; age 70, VC = 60%

d. Mucosal degeneration, decreased ciliary action, decreased phagocytic activity

The Respiratory System

2. Alveoli

B. Age-related changes

a. Fusion between adjacent alveolar walls = decreased respiratory membrane surface area

b. Increased collagen + decreased elastin = decreased compliance and diminished ventilation

c. Interstitial fluid changes hamper oxygen transport across respiratory membrane

d. Altogether, these changes cause declining blood oxygen levels with aging

The Respiratory System

3. Lungs

B. Age-related changes

a. Lose some elastic recoil, thus less resistance to expansion, due to changes in elastin

b. Lower lung regions to be poorly ventilated, causing decreased blood saturation with oxygen

c. Alveolar air isn’t exchanged as well with tidal air

d. Respiratory rates do not increase as well with decreased blood oxygen or increased blood carbon dioxide

e. Decreased forced vital capacity and FEV1

The Respiratory System

4. Structural changes in the thorax

B. Age-related changes

a. Rounding of thoracic vertebrae kyphosis

b. Rib cartilages calcify

c. Decreased muscle tone in diaphragm and intercostals

d. Breathing while lying down may be more difficult due to increases in intrabdominal pressure (fat) and because older folks tend to be diaphragmatic breathers

The Respiratory System

C. Age-related dysfunctions

1. Chronic obstructive pulmonary disease (COPD)

a. Obstructive disease limits expiration

b. Decreased ratio of FEV1:FVC

c. Symptoms

d. Causes

i. Emphysema

ii. Chronic bronchitis

The Respiratory System

C. Age-related dysfunctions

2. Pneumonia

a. Bacterial, viral, fungal infections lead to exudate-filled air sacs, causing decreased gas exchange with blood

b. Community- vs. hospital-acquired

c. Aspiration pneumonia

a. Bacterial infection leading to nodule formation

b. Nodules replace functional lung tissue

3. Tuberculosis

The Respiratory System

C. Age-related dysfunctions

4. Pulmonary embolism

a. What is an embolus?

b. How does it affect respiratory function?

end

The Respiratory System

D. Take home messages

1. Decreased lung elasticity, increased rigidity of thorax and bronchial tree, and changes in spinal curvatures lead to:

a. Increased breathing effort

b. Decreased maximum breathing capacity and vital capacity

2. Gradual loss of respiratory membrane surface area and poor exchange between alveolar air and tidal air lead to:

a. Decreased oxygen saturation of blood

b. Increased carbon dioxide in blood