Fundamentals of Biology - Chapter Outlines: Chapter 40 Respiration, Gas Exchange
Gas pressure = force / unit area
What increases pressure?
- Gases diffuse down pressure gradients
Air = 78% nitrogen, 21% oxygen
Atmospheric pressure = 760 mm Hg
Partial pressure of oxygen =
Respiratory Surface
- thin epithelium
- moist
- gas molecules dissolve
Fick's Law
- the more extensive the surface area and the larger the partial pressure gradient -
Factors Influencing Gas Exchange
1. Surface-to-volume ratio
2. Ventilation
3. Transport pigments
Human Respiratory System
FUNCTIONS
- gas exchange
- speech
- enhances venous
- eliminates excess heat
- acid-base balance
- filters
- modifies blood
From airways to lungs:
Nasal cavity
Pharynx
Larynx
Trachea
- lined with pseudostratified ciliated
- mucus escalator
Bronchus
-Heimlich maneuver
Lungs
- "bronchial tree"
- alveoli
- clustered in sacs
- where gas exchange occurs
Pleural Cavity
- outer surface of lungs covered with visceral pleura
- inner surface of thorax covered by parietal pleura
Pleurisy
Breathing = cyclic reversals
INHALATION
- diaphragm contracts
- external intercostal muscles contract
- increases volume
- decreases pressure
- air flows into
EXHALATION
- relax diaphragm
- decrease volume
- increases pressure
- air moves out
Lung Volumes
Vital capacity
Tidal volume
Gas Exchange
- in alveolus
- oxygen and carbon dioxide diffuse passively
3 components of respiratory membrane:
1. alveolar
2. fused basement membranes
3. capillary
Oxygen Transport
- 98.5% of oxygen
Hemoglobin (Hb) = 4 chains, 4 heme groups
- saturated
Carbon Dioxide Transport
10% dissolved in blood
30% binds with Hb
60% as bicarbonate
enzyme in red blood cells (carbonic anhydrase)
- enhances bicarbonate reaction
"Into Thin Air"
Hypoxia=cellular oxygen deficiency
"Altitude Sickness"
Mountain Residents:
- more alveoli
- larger heart ventricles
- more mitochondria
- hemoglobin with greater affinity
Acclimatization - erythropoietin produced by kidneys
Review
Review questions 1-3, 7-8
Self quiz 4-11
Critical Thinking #3 + how does the Heimlich maneuver work?