Download The Circulatory System Lecture

THE CIRCULATORY SYSTEM
WHAT IS THE CIRCULATORY SYSTEM?
• The circulatory system is
a vast network of
organs and vessels that
are responsible for the
flow of blood, nutrients,
hormones, oxygen and
other gases to and from
cells.
WHAT MAKES UP THE CIRCULATORY
SYSTEM?
• Heart
• Blood Vessels
• The Blood
• The Lungs (not
going over this
until later
THE HEART
• The heart is the size of your fist.
• The heart is located slightly to the left of the
middle of your chest.
• The heart is made up almost entirely of strong
muscle tissue and is protected by your rib
cage.
• The heart contracts (tightens) and relaxes
automatically about 70 times a minute to
pump blood out through the arteries.
• The heart has two sides separated by a
muscle wall called the septum.
• The right side of the heart is smaller and
weaker and it pumps blood only to the lungs.
• The stronger left side pumps blood around the
body.
• The heart consists of four hollow chambers:
the right atrium, left atrium, right ventricle, and
left ventricle.
BLOOD VESSELS
• Tubular structures
which carry blood
through the tissues
and organs
• Artery
• Vein
• Capillary
ARTERIES
• Arteries are a tube-like blood
vessel that CARRY BLOOD
AWAY FROM THE HEART.
• Arteries run alongside most of
the veins that return blood to
the heart.
• The walls of arteries are
muscular and can expand or
relax to control the blood flow.
• An arteriole is a smaller branch
off an artery. Arterioles branch
into microscopic capillaries.
• The aorta is the main artery
that carries blood away from
your heart to the rest of your
body.
• After the blood leaves the
heart through the aortic
valve, it travels through the
aorta, making a caneshaped curve that connects
with other major arteries to
deliver oxygen-rich blood to
the brain, muscles, and other
cells.r cells.
The Superior Vena Cava and the Inferior Vena Cava
are the two largest veins in the body and bring the
blood flow into the heart from above and below.
VEINS
• Veins are pipes in the body
that carry blood BACK TO THE
HEART.
• Unlike arteries, most veins carry
‘used’ blood back to the heartthe body cells have taken the
oxygen they need from the
blood, so it is low in oxygen.
• When blood is low in oxygen, it
is a dark, purplish blue color,
unlike the bright red of the
oxygenated blood carried by
the arteries.
• Inside most veins are flaps that
act as valves to make sure that
the blood only flows one way.
PULMONARY VALVE
•
Closes off the lower
right chamber (or
right ventricle).
•
Opens to allow
blood to be
pumped from the
heart to the lungs
(through the
pulmonary artery)
where it will receive
oxygen.
HEART VALVES
TRICUSPID VALVE
• Closes off the upper right chamber (or atrium)
that holds blood coming in from the body.
• Opens to allow blood to flow from the top
right chamber to the lower right chamber (or
from right atrium to right ventricle).
• Prevents the back flow of blood from the
ventricle to the atrium when blood is pumped
out of the ventricle.
MITRAL VALVE
•
Closes off the upper
left chamber (or left
atrium) collecting the
oxygen-rich blood
coming in from the
lungs.
•
Opens to allow blood
to pass from the
upper left side to the
lower left side (or from
the left atrium to the
left ventricle).
AORTIC VALVE
• Closes off the lower left
chamber that holds the
oxygen-rich blood before it
is pumped out to the
body.
• Opens to allow blood to
leave the heart (from the
left ventricle to the aorta
and on to the body).
CAPILLARIES
• Capillaries are the smallest of the
blood vessels and can only be
seen under a microscope.
• Capillaries link the arterioles to the
venules.
• It is through the capillary walls that
your blood passes oxygen, food,
and waste to and from each one
of your body cells.
• There are many more capillaries in
active tissues such as muscles, the
liver, and the kidneys than there
are tendons and ligaments.
BLOOD
• What is it?
• Blood is the reddish liquid that circulates around your body.
• What does it do?
• Blood carries oxygen and food to body cells, and takes carbon dioxide and other
waste away.
• Blood fights infection, keeps you warm, and distributes chemicals that control body
processes.
• What is it made of?
• Blood is made up of red cells, white cells, and platelets (tiny pieces of a cell that
make blood clot to stop bleeding), all carried in a liquid called plasma (although it
is 90% water, it contains hundreds of other substances including nutrients,
hormones, and special proteins for fighting infection).
• How much blood do we have?
• The amount of blood depends on the size of the person, as well as their gender. As
a general rule, adults have between 4 and 6 liters of blood (the bigger the person,
the more blood) and males have more blood than females.
UNDERSTANDING
BLOOD FLOW
• Follow the
numbers on the
diagram to
further
understand…
WHAT IS HEARTBEAT?
• Heartbeat is the regular squeezing of the heart muscle to
pump blood around the body.
• It’s what makes the ‘lup-dup’ sound that the heart makes
when it beats (can be heard through a stethoscope).
• Heartbeat is usually measured simply by the counting the
numbers of beats per minute (a.k.a. heart rate or pulse).
• When you exercise, your heart speeds up so more blood
can reach your muscles.
WHAT IS BLOOD PRESSURE?
• Blood pressure is the force of your
blood moving through your blood
vessels.
• Blood pressure is always recorded
as two numbers, such as 120/80,
where the top number is the
systolic pressure and the bottom
number is the diastolic pressure.
• Systole pressure is when the heart
muscle contracts (tightens) and
pumps blood.
• Diastole pressure is the pressure on
the arteries when the heart is at
rest in between heartbeats.
HOW THE HEART WORKS…
• http://www.newhealthadvisor.com/Circulatory-System-Organs.html
TEACHING GROUPS AND NONTEACHING GROUPS…
• ONE GROUP/ WEEK (yes, I changed it).
• Non-teaching group members will be responsible for a
separate assignment that focuses on the disease
portion of the system.