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The Respiratory System. Chapter 22. Objectives. SC.912.L.14.44 - Describe the physiology of the respiratory system including the mechanisms of ventilation, gas exchange, gas transport, and the mechanisms that control the rate of ventilation.
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The Respiratory System Chapter 22
Objectives • SC.912.L.14.44 - Describe the physiology of the respiratory system including the mechanisms of ventilation, gas exchange, gas transport, and the mechanisms that control the rate of ventilation. • SC.912.L.14.44 - Describe the physiology of the respiratory system including the mechanisms of ventilation, gas exchange, gas transport, and the mechanisms that control the rate of ventilation. • SC.912.L.18.6 - Discuss the role of anaerobic respiration in living things and in human society.
Functions • Provides extensive gas exchange surface area between air and circulating blood • Moves air to and from exchange surfaces of lungs
Functions • Protects respiratory surfaces from outside environment • Produces sounds • Participates in olfactory sense
Organization • Upper Respiratory System • above the larynx • Lower Respiratory System • below the larynx
Organs (Upper) • Nose • filters air • Sinuses • warm and moisten air • Pharynx
Larynx • Voice box • Made of cartilage, surrounds the glottis • Adam’s apple • Epiglottis • folds back over the glottis during swallowing • prevents entry of food & liquids into the respiratory tract
Sound Production • Air passes through the glottis • vibrates vocal folds • produces sound waves
Organs (Lower) • Trachea • windpipe • made of 15-20 rings of cartilage • Lungs: • bronchi • bronchioles • alveoli
Lobes of the Lungs • Lungs have lobes separated by deep fissures • Right Lung • 3 lobes • Left Lung • 2 lobes • cardiac notch
Respiration • External respiration • includes all processes involved in exchanging O2 and CO2 with the environment • Internal respiration • involves the uptake of O2 and production of CO2 within individual cells
Respiration • C6H12O6 + 6O2→ 6CO2 + 6H2O + ATP
Accessory Structures • Diaphragm • contraction results in inhalation • relaxation results in exhalation • Vocal cords
Gas Exchange • Occurs between alveolar air and capillary blood • Depends on: • partial pressure of the gases • diffusion of molecules between gas and liquid
Composition of Air • Nitrogen (N2) about 78.6% • Oxygen (O2) about 20.9% • Water vapor (H2O) about 0.5% • Carbon dioxide (CO2) about 0.04%
Hemoglobin • O2 binds to iron ions in hemoglobin molecules • Carbon Monoxide (CO) • binds strongly to hemoglobin • takes the place of O2 • can result in carbon monoxide poisoning
Changes in R.S. at Birth • Before birth: • pulmonary vessels are collapsed • lungs contain no air • During delivery: • placental connection is lost • blood PO2falls • PCO2 rises
Changes in R.S. at Birth • At birth: • newborn overcomes force of surface tension to inflate bronchial tree and alveoli and take first breath
Changes in R.S. at Birth • Large drop in pressure at first breath: • pulls blood into pulmonary circulation • closing foramen ovale and ductusarteriosus • redirecting fetal blood circulation patterns • Subsequent breaths: • fully inflate alveoli
Effects of Aging • Elastic tissues deteriorate: • reducing lung compliance • lowering vital capacity • Arthritic changes: • restrict chest movements • limit respiratory minute volume • Emphysema: • affects individuals over age 50 • depending on exposure to respiratory irritants (e.g., cigarette smoke)
Coordination of Respiratory & Cardiovascular Systems • Improves efficiency of gas exchange • Increases respiratory drive • Raises cardiac output and blood flow