Transcript AP Biology Animal Form and Function Respiratory ppt.

AP BIOLOGY ANIMAL
FORM AND FUNCTION
Respiratory System
Gas Exchange Occurs Across
Specialized Respiratory Surfaces
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Animal cells require O2 for aerobic respiration. If
cells are not directly exposed to the outside
environment, then some mechanism must provide gas
exchange to internal cells—delivering O2 and
removing waste CO2.
Respiration vs. Cellular Respiration
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Respiration—the
movement of gases
into and out of the
entire organism.
It is also used to
describe cellular
respiration—the
process of producing
ATP within
mitochondria
Gas Exchange in Different Animals
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Direct with environment:
some animals are small
enough they can exchange
gas directly with the
environment.
Many of these animals
such as the Platyhelminthes
(flatworms) have large
surface areas—every cell
is either exposed to the
environment or close
enough so that gases can
diffuse directly in and out.
Gills
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Gills are evaginated
structures (outgrowths from the
body) that have large surface
areas over which gas
exchange occurs.
Inside the gills, a circulatory
system removes the oxygen
and delivers waste CO2.
In some animals, such as
Polychaete worms (Annelids),
the gills are external and
unprotected. In other animals
such as fish, gills are internal
and protected.
In fish, water enters the mouth, passes
over the gills, and exits through the gill
cover (operculum). Countercurrent
exchange between the opposing
movements of water and blood
maximizes diffusion of O2 in and CO2
out.
Tracheae
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Insects have chitin-lined
tubes, or tracheae, that
permeate their bodies.
Oxygen enters (and
CO2 exits) the tracheae
through openings called
spiracles
Diffusion occurs across
moistened tracheal
endings.
Lungs
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Lungs are invaginated
surfaces (cavities
within the body of the
animal).
Special kinds of lungs,
called book lungs
occur in many
spiders—they are
stacks of flattened
membranes enclosed in
an internal chamber.
Gas Exchange in Humans
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Many different organs
are involved in human
gas exchange:
Nose
Pharynx
Larynx
Trachea
Bronchi, Bronchioles
Alveolus
Lungs
Diaphragm
Nose, Pharynx, Larynx
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Air enters the nose and
passes through the nasal
cavity, pharynx and
larynx.
Larynx—voice box that
contains the vocal cords
Pharynx—intersection
where paths for food
and air cross
Nasal cavity—warms
and cleans the air
Trachea
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After passing through
the larynx, air enters the
trachea
The trachea is a
cartilage-lined tube.
When the animal is
swallowing, a special
flap called the epiglottis
covers the trachea,
preventing the entrance
of solid and liquid
material.
Bronchi, Bronchioles
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The trachea branches
into two bronchi, which
enter the lungs and
then branch
repeatedly, forming
narrower tubes called
bronchioles.
Alveoli and Capillaries
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The bronchioles end in
little air sacs called
aleveoli.
Each alveoli is densely
covered with
capillaries.
The arteries are
carrying deoxygenated blood
from the heart.
Alveolus
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Gas exchange occurs by
diffusion across the moist,
sac membranes of the
alveoli.
Oxygen diffuses into the
moisture covering the
membrane, through the
alveolar wall, through the
blood capillary wall, into
the blood, and into red
blood cells. CO2 diffuses in
the opposite direction.
http://highered.mcgrawhill.com/sites/0072495855/s
tudent_view0/chapter25/ani
mation__gas_exchange_durin
g_respiration.html
Bulk flow of O2
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The circulatory system
transports O2 throughout
the body within red blood
cells. Red blood cells
contain hemoglobin, ironcontaining proteins to
which O2 bonds.
Oxygen diffuses out of
red blood cells, across
capillary walls, into
interstitial fluids (the fluids
surrounding the cells) and
across cell membranes.
Bulk flow of CO2
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Most CO2 is
transported as
dissolved bicarbonate
ions (HCO3-) in the
plasma, the liquid
portion of the blood.
The formation of
HCO3- occurs in the
red blood cells, then it
diffuses back into the
plasma.
Some CO2 does not become HCO3-,
instead it mixes directly with the plasma
or binds to amino groups of the
hemoglobin in red blood cells.
Mechanics of Respiration
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Air is moved into and out of lungs by changing their volume.
The volume of the lungs is controlled by the contraction of the
diaphragm (a thin muscle under the lungs)
When the lung volume increases, the air pressure inside the
lungs decreases and air rushes into the lungs.
http://highered.
mcgrawhill.com/sites/0
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dent_view0/cha
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When the
diaphragm and
intercostal muscles
relax, the volume
of the lungs
decreases, raising
the pressure on
the air, causing
the air to rush out.
Control of Respiration
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Chemo-receptors in the carotid
arteries (arteries that supply blood to
the brain) monitor the pH of the
blood.
When a body is active, CO2
production increases. When the CO2
that enters the plasma is converted to
HCO3- and H+, the blood pH drops.
In response, the chemo-receptors send
nerve impulses to the diaphragm and
respiratory rate is increased.
This results in a faster turnover in gas
exchange and blood pH returns to
normal.
Respiratory System Quiz
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http://www.rcs.rome.g
a.us/hargett/anatomy
/lungs/rspdia.htm
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Amazing facts about
the respiratory system:
http://warriors.warren
.k12.il.us/dburke/ama
zingfactsrespiratory.ht
m