What is the Circulatory System?
• Circulatory system describes both the
cardiovascular system and the lymphatic
system
• Both systems work closely together to move
fluids around your body and protect it from
disease
• The two systems help maintain homeostasis
• Both systems are made up of vessels
• Both systems are part of the body’s defense
against bacteria, viruses and other pathogens
• Your heart, blood and blood vessels make up your
cardiovascular system
• Blood is the fluid that carries gases, nutrients and
wastes through the body
• It is a closed circulatory system – the blood is
carried in vessels that form a loop
• The lymphatic system is a group of organs and
tissues that collect the fluids that leak from blood
and returns it to the blood
• The leaked fluid is called lymph
• It is an open circulatory system – lymph can move
in and out of the vessels
How Do The Systems Work Together?
• Every time your heart pumps, a little fluid is forced
out of the thin walls of the tiniest blood vessels
called capillaries
• Most of the fluid is reabsorbed by the capillaries
• The rest of the fluid is collected by lymph capillaries
• Lymph capillaries absorb fluid, dead cells and
pathogens from around body cells
• The fluid, called lymph is returned to the
cardiovascular system when it drains into blood
vessels at the base of the neck
• The lymphatic system is where white blood cells
mature - where they attack invading pathogens
Parts of the Lymphatic System
• Lymph nodes are small, bean – shaped organs
that remove pathogens and dead cells from
lymph
• Lymph nodes are concentrated in the armpits,
neck and groin
• Infection – fighting cells, called white blood cells,
are found in lymph nodes
• When pathogens cause an infection, the number
of white blood cells can increase greatly
• the increased number causes the lymph nodes
to become swollen and painful
• Lymph vessels are the thin walled vessels of the
lymphatic system
• They carry lymph back to lymph nodes
• From the lymph nodes, the fluid is returned to the
cardiovascular system
• Vessels have valves inside them to stop lymph from
flowing backwards
• Bone marrow is part of the lymphatic system – the
soft tissue inside the bone produces blood cells
• Tonsils – small lymphatic organs at the back of the
throat and tongue
• Help defend the body against infection
• White blood cells in the tonsil tissue trap
pathogens
• An infection of the tonsils is called
tonsillitis – they become swollen and are
painful
• Spleen – the largest lymphatic organ – it
stores white blood cells and allows them
to mature
• As blood flows through the spleen, white
blood cells attack pathogens in the blood
Disorders of the Lymphatic System
• Lymphoma is a type of cancer that often begins in a
lymph node
• The swelling it can cause in the node is called a
tumor
• Lymphedema is a swelling of body tissues caused by
a blockage or injury to lymph vessels
• Lymph vessels are unable to drain lymph from a
certain area and the area becomes swollen
• Bubonic plague is a bacterial infection of the
lymphatic system
• The bacteria can enter the body through the bite of
an infected flea
Parts of the Cardiovascular System
• The cardiovascular system is the organ system that
carries nutrients, gases and hormones to body cells
and waste products from the body cells
• Heart – the pump that sends blood around the
body
• when heart muscle contracts, it squeezes the blood
inside the heart
• The squeezing creates a pressure that pushes blood
through the body
• Your heart has a left side and a right side – the two
sides are separated by a thick wall
Heart Anatomy
• The right side of the heart pumps oxygen – poor
blood to the lungs
• The left side pumps oxygen – rich blood to the
body
• Each side has an upper chamber and a lower
chamber
• The upper chamber is called an atrium
• The lower chamber is called a ventricle
• Blood enters the atria and is pumped down to the
ventricles
• Flap – like structures called valves are located
between the atria and the ventricles and where
large vessels are attached to the heart – valves
prevent blood from flowing backward
Blood
• Blood is a type of connective tissue that is part of
the cardiovascular system
• It serves as a transport system, providing supplies
for cells, carrying chemical messages and removing
wastes so cells can maintain homeostasis
• Blood contains cells, fluid and other substances
• It travels through miles and miles of blood vessels
Blood Vessels
• Blood travels throughout your body in tubes called
blood vessels
• The three types of blood vessels are arteries,
capillaries and veins
• Arteries – blood vessels that carry blood away from
the heart
• Each heartbeat pumps blood into your arteries at
high pressure, which is your blood pressure
• Capillary – a tiny blood vessel that allows the
exchange of carbon dioxide and wastes between
body cells and the blood – capillary walls are one
cell thick
• Vein – a blood vessel that carries blood back to the
heart – not under as much pressure as arteries
What is Blood Made Of?
• Plasma – the fluid part of the blood - a mixture of
water, minerals, nutrients, sugars, proteins and
other substances
• Platelets – tiny pieces of larger cells found in bone
marrow
• When you cut yourself you bleed because blood
vessels are cut open – as soon as bleeding starts,
platelets begin to clump together to form a plug –
reduces blood loss – release a chemical to form tiny
fibers
• White blood cells – fight pathogens such as bacteria
and viruses – when they find one they destroy it
• Other white blood cells form antibodies
• Antibodies are chemicals that identify pathogens
• White blood cells destroy dead or damaged body
cells
• Red blood cells – disk – shaped cells that do not
have a nucleus
• They bring oxygen to every cell in your body
• Each red blood cell has hemoglobin – an oxygen –
carrying protein
• The disk shape of the red blood cell helps them
squeeze into capillaries
How Does Blood Move Through the
Body?
• Blood is pumped from the right side of the heart to the
lungs
• From the lungs it moves into the left side of the heart
• From the left side of the heart the blood is pumped to
the body
• Blood in the arteries that come out of the heart is
under great pressure from the pumping action of the
heart
• Veins carry larger volumes of blood more slowly – less
pressure
• Blood moves in two loops or circuits –pulmonary
circulation (blood flow between heart and lungs) and
systemic circulation (blood flow between heart and the
rest of the body)
How Does Circulation Help maintain
Body Temperature?
• When the brain senses that that body temperature
is rising, it signals blood vessels in the skin to widen
• As the blood vessels get wider, heat from the blood
is transferred to the air around the skin
• The transfer helps lower body temperature
• When the brain senses the body temperature is
getting too low, it signals the blood vessels near the
skin to get narrower
• This allows blood to stay close to internal organs to
keep them warm
Problems that Affect the
Cardiovascular System
• Atherosclerosis – hardening of the artery walls
caused by the build up of cholesterol and other
lipids
• Build up causes the blood vessels to become
narrower and less elastic
• Hypertension – abnormally high blood pressure –
may be caused by atherosclerosis
• Heart attack – happens when an artery that
supplies blood to the heart becomes blocked and
the heart muscle tissue does not get oxygen
• Stroke – a blood vessel in the brain becomes
blocked or bursts – as a result, that part of the
brain receives no oxygen
• https://www.youtube.com/watch?v=JerRPgnVGs