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Anatomy & Physiology 2 Canale
Respiratory System: Exchange of Gases
Why is it so hard to hold your breath for a long time?
Discuss! : )
Every year carbon monoxide poisoning kills 500 people and sends another
40,000 to hospital emergency rooms. Why is carbon monoxide so deadly?
Human Respiratory System
Figure 10.1
Nose
Passageway for air
Mouth
Passageway for food and air
Epiglottis
Covers larynx during swallowing
Pleural membranes
Cover the lungs and line the chest cavity
Lung
Organ of gas exchange
Intercostal muscle
Moves ribs during respiration
Nasal cavity
Filters, warms, and moistens air
Larynx (Voice box)
Production of sound
Trachea (Windpipe)
Main airway
Bronchi
Branching airways
Pharynx (Throat)
Common passageway for air, food, and liquid
Alveoli
Air sacs for gas exchange
Right lung Left lung Rib
Diaphragm
Skeletal muscle of respiration
UP
PE
R R
ES
PIR
AT
OR
Y
TR
AC
T
LO
WE
R R
ES
PIR
AT
OR
Y
TR
AC
T
Animation—The Human Respiratory System
Respiration Processes
• Breathing (ventilation): moving air in and out of lungs
• External respiration: gas exchange between air and blood
• Internal respiration: gas exchange between blood and tissues
• Cellular respiration: oxygen use to produce ATP, carbon dioxide as waste – inside the cell (mitochondria! )
The Upper Respiratory Tract
Figure 10.2
Nasal cavity
External nose
Nostril
Tongue
Larynx
Esophagus
Epiglottis
Glottis
Pharynx
Opening of the
auditory tube
Sinuses
Trachea
Upper Respiratory Tract
• Functions
1. Passageway for respiration
2. Receptors for smell
3. Filters larger foreign material from incoming air
1. Moving cilia – hair-like projections – the mucus traps dust and foreign particles and cilia moves this to the back of nasal cavity where we cough it or swallow it.
4. Moistens and warms incoming air
5. Resonating chambers for voice
The Lower Respiratory Tract
Figure 10.3
Trachea
Bronchioles
Left
bronchus
Clusters
of alveoli
Larynx
Right
bronchus
Lower Respiratory Tract
• Functions
1. Larynx: maintains an open airway, routes food and air appropriately, assists in sound production
2. Trachea: transports air to and from lungs
3. Bronchi: branch into lungs
4. Lungs: transport air to alveoli for gas exchange
Gas Exchange Between the Blood and Alveoli
Figure 10.8a (1 of 3)
Gas Exchange Between the Blood and Alveoli
Figure 10.8a (2 of 3) and (3 of 3)
Exchange due to partial pressures /concentration gradients
Breathing: Pressure Gradient
• Inspiration AND expiration: air in AND air out cycle 1. Relaxed state
• Diaphragm and intercostal muscles relaxed
2. Inspiration
• Diaphragm contracts, pulling muscle down; intercostal muscles contract, elevating chest wall and expanding volume of chest, lowering pressure in lungs, pulling in air
3. Expiration
• Muscles relax; diaphragm resumes dome shape; intercostal muscles allow chest to lower, resulting in increase of pressure in chest and expulsion of air
Respiratory Cycle
Figure 10.9
Lung Volumes and Vital Capacity
Tidal volume Volume of air inhaled and exhaled in a single
breath
Dead space volume Volume of air that remains in the airways and
does not participate in gas exchange
Vital capacity Maximal volume that can be exhaled after
maximal inhalation
Lung Volumes and Vital Capacity
Inspiratory reserve volume Volume of air that can be inhaled beyond the tidal
volume
Expiratory reserve volume Volume of air that can be forcibly exhaled beyond
the tidal volume
Residual volume Volume of air remaining in the lungs, even after a
forceful maximal expiration
Measured by spirometer
Measurement of Lung Capacity
Figure 10.10a
Gas Exchange and Transport: A Passive Process
Gases diffuse according to their partial pressures External respiration: gases exchanged between air
and blood Internal respiration: gases exchanged with tissue
fluids Oxygen transport: bound to hemoglobin in red
blood cells or dissolved in blood plasma Carbon dioxide transport: dissolved in blood
plasma, bound to hemoglobin, or in the form of plasma bicarbonate
How O2 and CO2 are Transported in Blood
Figure 10.12 (1 of 2)
How O2 and CO2 are Transported in Blood
Figure 10.12 (2 of 2)
Regulation of Breathing: Nervous System Involvement
• Respiratory center in the medulla oblongata
– Establishes basic breathing pattern
• Chemical receptors
– Monitor carbon dioxide, hydrogen ions, and oxygen levels
• Medulla
– Sensitive to hydrogen ions in cerebrospinal fluid resulting from carbon dioxide in blood
Regulation of Breathing
Figure 10.13
Regulation of Breathing: Nervous System Involvement
• Carotid and aortic bodies
– Sensitive to carbon dioxide, pH, and oxygen levels
• Conscious control
– Resides in higher brain centers
– Ability to modify breath
Disorders of Respiratory System
• Reduced air flow 1. Asthma – spasmodic contraction of bronchi 2. Emphysema - alveoli are permanently impaired 3. Bronchitis – inflammation of the bronchi
• Infections 1. Pneumonia – bacterial or viral infection – inflamed lungs 2. Tuberculosis – bacteria Mycobacterium tuberculosis 3. Botulism - Clostridium botulinum bacteria
Disorders: 1. Lung cancer 2. Congestive heart failure 3. Cystic fibrosis
True or false? Production of mucus is not a normal part of the
respiratory system.
True
False
True or false? The pulmonary artery carries blood that is low in oxygen.
• True
• False
Doctors measure lung function by having a person inhale and then exhale forcibly into a device called a spirometer. What does a
spirometer measure?
A. The volume of air that a person can breathe in and out in a single breath
B. How quickly air can be moved in and out of the lungs
C. How much muscle the lungs have
D. Both A and B
The chemicals in tobacco smoke ______.
A. increase mucus production
B. destroy cilia
C. cause mucus pooling, leading to infections
D. All the above
Gas exchange in the respiratory system occurs in the __________.
A. trachea
B. bronchiole tree
C. alveoli
D. pleural cavity
When you take a deep breath then hold it, you are using your
__________.
A. tidal volume
B. inspiratory reserve volume
C. expiratory reserve volume
D. vital capacity
Most of the carbon dioxide carried in the blood is in the form of _________.
A. oxyhemoglobin
B. dissolved carbon dioxide
C. carbonic acid
D. bicarbonate
The principle chemical monitored in the respiratory system is __________.
A. oxygen
B. carbon dioxide
C. carbonic acid
D. oxyhemoglobin