Transcript Cardiovascular System

CARDIOVASCULAR SYSTEM
The Cardiovascular System
• A closed system of the heart and blood vessels
– The heart pumps the blood.
– Blood vessels allow blood to circulate to all parts of
the body.
• The function of the cardiovascular system is to
deliver oxygen and nutrients and to remove
carbon dioxide and other waste products.
• Your heart has special pacemaker cells that
control the pumping action of the heart with an
electrical signal.
Pace maker cells
The Heart
• Location
– In the chest between the lungs.
• Orientation
– The pointed tip is directed toward left hip.
• About the size of
your two fists
together.
The Heart
• The heart is surrounded by a layer of tissue that
protects it from damage and bacteria.
• The walls of the heart are 3 layers thick
– Epicardium (Outer Layer)
– Myocardium: (Middle Layer) – cardiac muscular layer
– Endocardium
(Inner Layer)
Myocardium
Four Chambers of the Heart
• Left and right refers to persons right and left sides,
not yours.
• Right/Left Atrium (Atria plural)
– Receives blood into the heart
• Right/Left Ventricle
– Pumps blood out of heart
Internal Anatomy and Organization
• What separates the right side from the left side of
the heart is the septum, in the heart oxygen rich and
oxygen poor blood do not mix.
• To control the blood flow through the heart there are
valves that control the movement of blood through
the chambers and out of the heart.
• Atrioventricular (AV) valves: open and close to move
blood from the atria to the ventricles.
• Semilunar valves: open and close to permit blood out
of the heart.
Pathway of Blood
• Blood arrives at the heart in the atriums
• Blood leaves the heart from the ventricles
– In from body to the Right Atrium (deoxygentated)
– Right atrium to right ventricle (deoxygentated)
– Right ventricle out to lungs (becomes oxygenated)
– Back from lungs to left atrium (oxygenated)
– Left atrium to left ventricle (oxygenated)
– Left Ventricle to body (oxygenated)
Circulation
• Blood that has just picked up oxygen from the
lungs comes into the heart and goes through
the atrium and ventricles.
Aorta
• Blood leaves the heart through
the aorta: which takes blood
out to the body.
– The aorta is the largest blood
vessel in the body.
Circulation
• When blood leaves the heart and goes to the
lungs to pick up oxygen then returns to the
heart this is known as the pulmonary
circulation.
• When blood leaves the heart through the
aorta and goes out to the body to drop off the
oxygen and pick up waste products then
returns it is known as the systemic circulation.
Overview of the Cardiovascular System
Introduction to Cardiovascular System
• Oxygen rich blood that is leaving the heart is
carried through the arteries.
– Arteries carry blood away from the heart.
• Oxygen poor blood is carried in the veins from
the body towards the heart.
– Veins carry blood towards the heart
• Capillaries: network of blood vessels that
connects the arteries and veins.
• Heart  Artery  Capillaries  Veins  Heart
Blood Vessels
• The pressure in the blood vessels is highest in the
arteries and lowest in the veins.
• To cause changes in the blood vessel’s pressure the
vessels expand and contract.
– Using smooth muscle contractions.
• Muscles that can’t be voluntarily controlled (organs)
• Veins also use a skeletal pump:
– When muscle contractions push blood through the
veins.
– Used to return blood from legs
Blood Pressure
• Measurements by health professionals are
made on the pressure in large arteries
– Systolic—pressure during a heart contraction.
– Diastolic—pressure when heart is relaxed
– Write systolic pressure first and diastolic last
(120/80 mm Hg)
• Pressure in blood vessels decreases as
distance from the heart increases.
Blood Pressure
• Website
Variations in Blood Pressure
• Normal human range is variable
– Normal
• 140–110 mm Hg systolic
• 80–75 mm Hg diastolic
– Hypotension
• Low systolic (below 110 mm HG)
• Often associated with illness
– Hypertension (High blood pressure)
• High systolic (above 140 mm HG)
• Can be dangerous if it is chronic
High Blood Pressure
• When there is build up of fatty material in the
blood vessels it causes the vessels and heart
to have to work harder, and increased
pressure in the vessels.
– This is a disease known as Arthrosclerosis
• If this type of blockage occurs in the blood
vessels that supply oxygen to the heart
muscles it can cause a Heart Attack.
Stroke
• If a blockage occurs from a blood clot in the
brain a stroke can occur.