Transcript bio - AP Biology

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Also known as
the circulatory
system
The
cardiovascular
system is made
up of the heart,
blood, and blood
vessels
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Our heart is a muscle that keeps blood
flowing through our body, bringing
nutrients and oxygen to every cell
It circulates about two gallons of blood
throughout the body
The system begins in our lungs, where
blood picks up oxygen
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The heart takes the oxygen-rich blood
and pumps it out to all parts of the
body
After the cells in the body take in the
oxygen from the blood, the
deoxygenated blood returns to the
heart and is sent to the lungs to get
more oxygen
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The heart is made up of four
chambers separated by one-way
gateways called valves
It is divided into a right and left side
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The atria have relatively thin walls and
function as collection chambers
They only pump blood to the ventricles
Left atrium is a hollow chamber that
collects oxygen-rich blood from the
pulmonary vein before sending it to the
left ventricle.
Right atrium is a hollow chamber that
collects blood lacking oxygen from the
vena cava before sending it to the right
ventricle
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The chambers that pump blood out
of the heart are called the ventricles.
The ventricles have thicker walls and
are much more powerful than the
atria
The ventricles are the major pumping
chambers for delivering blood to the
pulmonary (right ventricle) and
systemic (left ventricles) circulations
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Left ventricle is a hollow chamber
that collects oxygen-rich blood from
the left atrium before sending it to the
aorta
Right ventricle is a hollow chamber
that collects blood lacking oxygen
from the right atrium before sending it
to the pulmonary artery
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The valves each consist of flaps of
connective tissue that prevent
backflow of blood
Atrioventricular valves and Semilunar
valves
Pressure generated by powerful
contraction of the ventricles closes
the AV valves, keeping blood from
flowing back into the atria
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Tricuspid valve- valve with three
cusps; situated between the right
atrium and the right ventricle;
allows blood to pass from atrium to
ventricle and closes to prevent
backflow when the ventricle
contracts
Mitral valve- valve with two cusps;
situated between the left atrium
and the left ventricle
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Semilunar valves are located at the two
exits of the heart
The blood is pumped out into the
arteries through semilunar valves, which
are forced open by pressure created by
ventricular contraction
The semilunar valves close when the
blood starts to flow back toward the
heart, so this prevents blood from
flowing back into the ventricles
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Pulmonary valve- between the right
ventricle and the pulmonary artery;
prevents blood from flowing from the
artery back into the heart
Aortic valve- between the left
ventricle and the aorta; prevents
blood from flowing from the aorta
back into the heart
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Aorta- Large artery that distributes
oxygen-rich blood from the heart to
the rest of the body.
Pulmonary Artery- carries blood
lacking oxygen from the hearts right
ventricle to the lungs
Pulmonary vein- carries oxygen-rich
blood from the lungs into the hearts
left atrium
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Coronary arteries- vessels that provide
the heart muscle with the oxygen-rich
blood it needs to keep its tissues
healthy. Two main coronary arteries
branch off from the aorta, and each
of these arteries branches again into
yet more arteries that supply
oxygenated blood to the different
parts of the heat
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Vena Cava (superior)-Carries blood
lacking oxygen from the head, neck,
and arms into the right atrium
Vena Cava (inferior)- carries blood
lacking oxygen from legs and other
lower parts of the body into the right
atrium
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When it contracts it
pumps blood
When it relaxes its
chambers fill with blood
Complete sequence of
pumping and filling is
called the cardiac cycle
Contraction phase is
called systole
Relaxation phase is
called diastole
The cardiac output is the
blood volume pumped
per minute
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3 basic blood vessels
include capillaries
arteries and veins
Transport blood from the arteries to
the veins
 Oxygen, carbon dioxide, nutrients,
and wastes are exchanged through
the walls
Capillaries are so small that red blood
cells can only travel through them in
single file!
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Carry blood away from the heart
Walls provide strength and elasticity
Deliver oxygen-rich blood to the
capillaries
We can measure heart rate by
counting the contractions of the
artery. That’s how a pulse is taken.
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Convey blood back to the heart at
low velocity and pressure after the
blood has passed through the
capillaries
Blood flows through veins as a result
of muscle action
The Respiratory System
Trachea
(wind pipe)
Ribs
Alveoli
Bronchus
Bronchioles
Intercostal
muscles
Lung
Diaphragm
The Respiratory System
The purpose of the respiratory system is to…
bring the air we breathe into close contact
with the blood so that oxygen can be
absorbed and carbon dioxide removed.
Basically it consists of:
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A pair of lungs connected
to the mouth via the
trachea and bronchi.
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The ribs and intercostal
muscles of the chest which
protect the lungs, trachea
and bronchi.
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Air enters the nostrils
passes through the nasopharynx,
the oral pharynx
through the glottis
into the trachea
into the right and left bronchi, which
branches and rebranches into
bronchioles, each of which terminates in a
cluster of
Alveoli (Only in the alveoli does actual gas
exchange takes place).
The trachea or windpipe is
about 10 cm long and is
supported by C-shaped
rings of cartilage to
prevent the tube from
collapsing during
breathing.
The trachea
subdivides into
the left and right
bronchus.
The bronchi are
also strengthened
by cartilage.
The two bronchi
subdivide to form
an extensive
network of
Bronchioles that
deliver air to the
gas exchange
surfaces – the alveoli.
Air enters the body through
the nasal passages and
mouth, and passes via the
pharynx and larynx
to the trachea.
Air is delivered to
the alveoli as the
trachea branches
into bronchi and
bronchioles.
Lungs
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main organs of the respiratory system.
oxygen taken into the body and carbon
dioxide is breathed out.
red blood cells pick up the oxygen in the
lungs and carry it to all the body cells that
need it.
Then they pick up the carbon dioxide which
is a waste gas product produced by our
cells.
The red blood cells transport the carbon
dioxide back to the lungs and we breathe it
out when we exhale.
The Exchange of Gases within the Lungs
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The 2 bronchi, which lead to each lung divide into many bronchioles.
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These are less than 1mm in diameter and terminate in grape-like
clusters of tiny sacs called alveoli.
Thorax
Section of
lung
Single alveolus
Gas Exchange
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Occurs in the alveloi (air sacs)
Capillaries surround the alveoli and allow gas
exchange to occur between the blood and the
lungs
Gases diffuse from an area of high
concentration to an area of low concentration
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Deoxygenated blood - high CO2 low O2
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Alveoli - low CO2 high O2
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Therefore the CO2 goes from the blood to the
lungs and O2 goes from the lungs to the blood
Gas Exchange
Alveoli have
low CO2
high O2
Deoxygenated
blood
Oxygenated
blood
Alveoli
CO2
O2
Deoxygenated blood has
Oxygenated blood has
high CO2
low O2
low CO2
high O2
Trachea
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The trachea is sometimes called the
windpipe.
The trachea filters the air we breathe
and branches into the bronchi.
Bronchi
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The bronchi are two air tubes that
branch off of the trachea and carry
air directly into the lungs.
Diaphragm
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Breathing starts with a dome-shaped
muscle at the bottom of the lungs called
the diaphragm
When you breathe in, the diaphragm
contracts.
When it contracts it flattens out and pulls
downward. This movement enlarges the
space that the lungs are in. This larger
space pulls air into the lungs.
When you breathe out, the diaphragm
expands reducing the amount of space for
the lungs and forcing air out.
The diaphragm is the main muscle used in
breathing.
Negative Pressure Breathing
-we pull air instead of pushing it