Transcript The Circulatory System

The Circulatory
System
The Basics
• The main
components of the
circulatory system
are the heart,
blood vessels, and
blood.
• Together these
components
circulate blood
through out the
body.
Blood: Composition
• Blood is a viscous, or
sticky, fluid which
flows inside the
vessels of the
circulatory system.
• There is
approximately 5.5
Litres of blood in the
human body.
Blood: 3 Cell Types
• Blood is made up of blood plasma.
• Within the blood plasma there are 3
types of of cells.
• Red blood cells
• White Blood Cells
• Platelets
Blood: Red Blood Cells
• Red blood cells are
the most common
type of blood cell.
• They are disk shaped
and have no nucleus.
• They contain
haemoglobin, the
pigment that makes
blood red and also
transports oxygen.
Blood: White Blood
Cells
• There are fewer white
blood cells than red
blood cells in the
body.
• White blood cells help
protect the body from
infection, and
eliminate cell debris.
• There are also 5
different types.
Blood: Platelets
• Platelets are made up of cell fragments.
• These cell fragments contain substances
that allow the blood to clot.
Blood Types
• The membranes of the red blood cells
contain different proteins.
• These proteins are responsible for
creating the different blood types.
• Type A
• Type B
• Type AB
• Type O
Blood Vessels
• Blood vessels allow for blood to
circulate through out the body.
• There are 3 types of blood vessels.
• Arteries
• Capillaries
• Veins
Blood Vessels: Arteries
• Arteries carry blood away from the
heart.
• The largest arteries are elastic.
• As arteries get further from the
heart they get smaller, these are
called arterioles.
Blood Vessels:
Capillaries
• Capillaries are
microscopic blood
vessels that are
found in every body
tissue.
• There are several
million capillaries
found in the
circulatory system.
Blood Vessels: Veins
• When capillaries come
together they form
veins.
• Veins are responsible for
taking blood back to the
heart.
• Within veins there are
valves that allow blood
to flow to the heart, but
not in the opposite
direction.
The Heart
• The heart is divided into
four chambers: two atria
and two ventricles.
• Veins enter the atria
while arteries leave from
the ventricles.
• Also, there is an
atriovencular valve
which allows blood to
flow in one direction.
Heartbeat
• The heartbeat is the movement of the
heart which pumps blood.
• It is made up of three phases
• Atrial Systole
• Ventricular Systole
• Diastole.
Cardiac Cycle Phase 1
• Atrial Systole
occurs when:
• The atria contract
• Blood is pumped
through the
ventricles
• Blood travels
through the open
antriovencular
valves
Cardiac Cycle Phase 2
• Ventricular Systole
occurs when
• The ventricles
contract
• Sigmoid valves open
• Blood flows out into
the pulmonary artery
and aorta
• At the same time,
valves in ventricles
and aorta close.
Cardiac Cycle Phase 3
• Diastole occurs
when
• The heart relaxes
• Blood is drawn from
the venae cavae and
pulmonary veins
• The blood flows into
the atria.