The
Circulatory
System
1. Using your first two fingers (not
your thumb), try to find your pulse.
There are several places you can
check.
2. Once you have found a good pulse
point, have a partner time you for
15 seconds and count the number
of times you feel your pulse.
___________
3. Multiply that number by 4 to get the
resting beats per minute
_____________
The Circulatory System
• Made up of the cardiovascular system
and the lymphatic system
The Cardiovascular System
• Made up of (organs):
– heart
– blood vessels (veins
and arteries)
– blood
The Cardiovascular System
• Functions
– Carries nutrients, gases, hormones and
waste around the body.
• carbon dioxide and waste away
• oxygen, nutrients, and hormones to
– Helps your body maintain a balanced
temperature.
vocabulary
word!
• heart – hollow muscular organ that
pumps blood around the body.
• Size of your fist
• Located in the center of your
chest
• right side pumps oxygen
poor blood to the lungs
• left side pumps oxygen
rich blood to the body.
Structure of the Heart
• The heart has two sides
• Each side has an upper chamber
– Atrium
• Each side has a lower chamber
– Ventricle
How the Heart Works
• The heart’s action has two phases
– The heart relaxes and the atria fill with
blood
– The atria contract, blood is pumped into
the ventricles, then the ventricles contract
and send blood out of the heart
• Blood only travels in one direction, it
cannot flow backwards
Regulation of the Heartbeat
• The heart contains pacemaker cells
that tell the heart when to beat
– When you are exercising, excited, scared
etc…, your heart beats faster.
– When you are relaxed, calm, asleep etc…,
your heart beats slower.
vocabulary
word!
• blood – the tissue that carries gases,
hormones, nutrients and wastes through
the body.
• Helps the body maintain homeostasis
(balance)
FACT: blood is NEVER
blue!!!!
Oxygen rich blood
from an artery
Oxygen poor blood
from a vein
Unless you’re a horseshoe
crab.
vocabulary
word!
• blood vessels – the tubes that your blood
travels in.
– arteries
– capillaries
– veins
vocabulary
word!
Arteries
• arteries - carry oxygen rich blood away
from the heart.
– Walls are thick, strong and flexible
– Contain smooth muscle that can contract
and relax
Arteries
vocabulary
word!
Capillaries
• capillaries - tiny blood vessels where
material is exchanged between the
blood and the body’s cells.
• Oxygen and glucose rich blood from
the arteries goes into the capillaries
• From the capillaries needed materials
pass into the cells and waste material
is removed from the cells
Capillaries
vocabulary
word!
Veins
• veins - carry oxygen poor blood back to
the heart.
– Veins have 3 layers to their walls too but
the wall is much thinner
– Muscle contractions, breathing and valves
help move blood through veins
Veins
Create this chart in your notes
and complete.
artery
capillary
Blood moves in circuits inside blood
vessels.
• Oxygen poor blood enters the right
atrium.
• It is then pumped to the right ventricle,
then to the lungs.
• It picks up oxygen and goes back to
the left atrium
• It pumps from the left atrium into the
left ventricle.
• The left ventricle pumps oxygen rich
blood to the rest of the body.
Blood moves in two circuits around the
body:
Maintaining body temperature
• Blood circulating through the body
helps maintain homeostasis.
• When we are hot, blood vessels
enlarge to allow more blood close to
the surface of our skin where it can
be cooled.
• When we are cold, blood vessels
constrict to keep as much blood
close to the chest as possible to
keep us warm.
The Lymphatic System
• Made up of (organs):
– lymph nodes
– lymph vessels
– lymph
– spleen
– bone marrow
– Tonsils
– thymus
The Lymphatic System
• Functions
– Carries white blood cells.
– Helps remove waste from the blood.
– Helps us heal and fight disease.
vocabulary
word!
• lymph – clear to white fluid found in
blood that contains white blood cells.
• Lymph can move in and out of blood
vessels and body tissues.
• It helps prevent infection and heals
injuries.
• lymph nodes – small, bean shaped
organs that remove dead cells and
pathogens.
• Found mostly in the arm pits, neck and
groin.
• Stores white blood cells that help fight
infection.
• bone marrow – soft tissue inside of
bones where red blood cells are
produced.
• tonsils – small lymphatic organs at the
back of the throat.
• Tonsils help defend the body against
infection.
• spleen – largest lymphatic organ. It
stores white blood cells.
Working together:
• These two systems work together to
form the circulatory system.
• Blood stays in the blood vessels
(closed loop).
• Lymph can travel in and out of lymph
vessels and into and out of blood
vessels (open loop).
Working together:
Working together: