Transcript Macro Respiration

Macro Respiration
Chapter 42
What you need to know
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The general characteristics of a
respiratory surface.
The pathway a molecule of oxygen
takes from the air until it is picked up
by the hemoglobin of a red blood cell.
Respiration
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Uptake of O2 and discharge of CO2
Respiratory Medium is the source of O2
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Air (21% O2)
Water (varies with temperature and salinity
but always less than 21%)
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As temp and salinity increase, O2 decreases
Gas diffuses based on gas pressure
(partial pressure)
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Always from high to low (simple diffusion)
Respiratory Surfaces
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Always moist, single cell layer, epithelial
tissue (skin cells)
Lungs, air sacs, trachea
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Gills
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In folding of body/skin *(favorable surface
area to volume ratio)
Reduces water loss for terrestrials
Outer folding of body/skin *
Countercurrent exchange
Skin
Types of Respiration
Skin Breathing (worms)
1.
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No specialized respiratory surface, high
surface area to body volume required,
they have to stay small, must live in moist
environments
Types of Respiration
Tracheal System (insects)
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Extensive branching tubes reach every cell, no
circulatory system required, low efficiency,
organisms are small and ectothermic
Types of Respiration
Gills (organisms)
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Two or more, countercurrent exchange,
high energy requirement
Types of Respiration
Lungs (terrestrial
vertebrates)
4.
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Large surface area
through intense infolding
Covered with moist
epithelial tissue
Human Pulmonary System
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Flow of air into the body:
Mouth or nose 
Pharynx (throat) 
Epiglottis (skin flap) 
Larynx (voice box) 
Trachea (windpipe) 
Bronchi (2 bronchus: 1 to each
lung) 
Lungs which contain bronchioles
(small tubules) and alveoli (tiny
air sacs at the end of each
bronchiole)
Functions of Organs
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Nasal cavity: cleans, moisturizes, and
warms air
Larynx: sound
Epiglottis: separating food from air
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Cartilage flap that covers the entrance to
the trachea, only opens when you breath
Nervous system cross inhibition prevents
swallowing and breathing at the same time
Functions of Organs
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Trachea & bronchi: ciliated epithelial cells
which secrete mucus to trap and remove
any remaining dirt/dust/debris particles
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Mucus is transported by cilia dispelling
mucus out the throat and nose
Cystic fibrosis is a recessive mutation
leading to thick mucus which is a
breeding ground for bacteria
Functions of Organs
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Lungs: spongy tissue with enormous
surface area (football field)
Right lung has 3 lobes, left lung has 2
Surrounded by capillaries
Gases pass through 2 cell layers:
alveoli cell and capillary wall cell
Gas Exchange
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Alveoli are tiny lung sacs 1 cell layer
thick
Gases diffuse from high to low
concentrations (higher O2 in alveoli,
higher CO2 in the blood)
Gas Transport
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Hemoglobin: quaternary protein, iron
chelate in vertebrate erythrocytes (RBC)
Myoglobin: similar to hemoglobin, O2
storing protein in muscles
Hemolymph: protein/copper chelate in
mollusks and arthropods
Most CO2 is bound in the blood liquid as
carbonic acid (HCO3-)
Mechanics of Breathing
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Diaphragm is a dome-shaped (relaxed)
muscle separating the thorax from the
abdomen
When the muscle contracts it flattens,
pulling down the lungs, which creates a
vaccuum = inhalation
Relaxation of the muscles = exhalation
Vital Capacity = maximum volume of air
in lungs
Control
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Inovluntary
Blood chemistry influences breathing
rate
Medulla oblongata (brain stem) has O2
sensors
Respiratory Diseases
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Infections: ears, nose, throat, bronchi
(bronchitus), lungs (pneumonia)
Allergies: hayfever
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Emphysema: repeated infections and
irritations leads to the replacement of
alveoli with scar tissue
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Asthma: extreme allergic reaction leading
to the constriction of bronchi
CF, smoking, pollution
Lung Cancer: mutated alveoli cells