Chapter 13The

Respiratory System

External RespirationExternal Respiration

1. Oxygen movement into the blood

alveoli have more O2

O2 moves by diffusion

Pulmonary capillary blood gains O2

2. CO2 movement out of the blood

Blood has more CO2

Pulmonary capillary blood gives up CO2

Blood leaving the lungs is O2 -rich and CO2- poor.

Which is Internal or External Respiration?Which is Internal or External Respiration?

Figure 13.11

Respiratory Disorders: Respiratory Disorders: 1. Chronic Obstructive Pulmonary Disease (COPD)1. Chronic Obstructive Pulmonary Disease (COPD)

Exemplified by chronic bronchitis & emphysema

Major causes of death & disability in US

Features

-history of smoking

-Labored breathing (dyspnea)

-Coughing & frequent infections

-Retain carbon dioxide

- are hypoxic & have respiratory acidosis

-Ultimately develop respiratory failure

EmphysemaEmphysema Alveoli enlarge as chambers break through

Chronic inflammation promotes lung fibrosis

Airways collapse during expiration

Much energy to exhale

Overinflation leads to a barrel chest

Cyanosis appears late in the disease

Chronic BronchitisChronic Bronchitis Mucosa of respiratory

passages becomes severely inflamed

Mucus production increases

Pooled mucus impairs ventilation and gas exchange

Risk of lung infection increases

Pneumonia is common

Hypoxia and cyanosis occur early

Chronic Obstructive Pulmonary Disease (COPD)Chronic Obstructive Pulmonary Disease (COPD)

Figure 13.13

Lung CancerLung Cancer Accounts for 1/3 of all

cancer deaths in the United States

Increased incidence associated with smoking

Three common types

- Squamous cell carcinoma

- Adenocarcinoma

- Small cell carcinoma

Sudden Infant Death syndrome (SIDS)Sudden Infant Death syndrome (SIDS) Apparently healthy

infant stops breathing and dies during sleep

Some cases are thought to be a problem of the neural respiratory control center

One third of cases appear to be due to heart rhythm abnormalities

AsthmaAsthma Chronic inflamed

hypersensitive bronchiole passages

Response to irritants with dyspnea, coughing, and wheezing

Developmental AspectsDevelopmental Aspects Lungs filled with fluid in the baby

Lungs not inflated until 2 weeks after birth

Surfactant that lowers alveolar surface tension is not present until late in fetal development and may not be present in premature babies

Developmental AspectsDevelopmental AspectsImportant birth defects

Cystic fibrosis – oversecretion of thick mucus clogs the respiratory system

Cleft palate

Newborns – 40 to 80 rpm

Infants – 30 rpm

Age 5 – 25 rpm

Adults – 12 to 18 rpm

Rate increases with old age

Respiratory Rate Changes Through Life

Aging EffectsAging Effects Elasticity of lungs

decreases

Vital capacity decreases

Blood oxygen levels decrease

Stimulating effects of carbon dioxide decreases

More risks of respiratory tract infection