Transcript Cardiovascular_System

11th Grade Anatomy
January 2007
Functions of the Cardiovascular
System
• Main transportation system of the
body.
– Transports nourishment from digestion
– Transports hormones
– Transports red blood cells that carry
oxygen
– Transports white blood cells that fight
disease
• Helps regulate body temperature
Blood
• Blood is considered the fluid of life
• A type of connective tissue
• The average adult has 5 liters of
blood in their body
What Makes up Blood?
• Fluid = 55%
– Plasma
• Cells = 45%
– Red Blood Cells
– White Blood Cells
– Platelets
What Do They Do?
• Plasma
– Consist of 90% water
– Consists of 10% dry mass
•Glucose
•Fats
•Proteins
•Hormones
•Vitamins
•Minerals
What Do They Do?
• Red Blood Cells
– Also called
erythrocytes
– Shape is biconcave
– They have a protein
called hemoglobin
which carries
oxygen
What Do They Do?
• White Blood Cells
– Also called leukocytes
– WBC’s are responsible for the defense of
an organism
– WBC’s are less numerous
– Unlike RBC’s, leukocytes have a nucleus
that is used to help identify what type of
WBC it is
• WBC’s are broken
into two categories:
– Granulocytes – have
granules and a
distinclty shapen
nucleus
•Neutrophil
•Eosinophil
•Basophil
– Lymphocytes –
single, large nucleus
•Lymphocyte
•Monocyte
• Platelets
– Also called
thrombocytes
– The main function of
platelets is to stop
the loss of blood
from wounds.
Blood Types
• There are two
chemicals that can be
found on the surface
of RBC’s: A & B
– Type A: has A chemical
– Type B: has B chemical
– Type AB: has both A &
B chemicals
• “Universal Acceptor”
– Type O: has neither
chemical
• “Universal Donor”
The Heart
• The heart is a muscular pump that is located
between the lungs.
• The heart pumps 7000 liters of blood a day
• Humans have a closed circulatory system –
meaning that blood is always enclosed by
vessels.
• The heart is composed of cardiac muscle
Heart
• The heart is composed of three layers:
– Endocardium
– Myocardium
– Epicardium
• The heart is divided into four hollow
chambers: 2 on the left & 2 on the right
– Right Atrium and Right Ventricle
– Left Atrium and Left Ventricle
Anatomy of the Heart
Blood Flow
• Deoxygenated blood enters the heart into the
right atrium from two large veins:
– Superior Vena Cava
– Inferior Vena Cava
• From the right atrium the blood will flow
into the right ventricle. The valve that
separates these two is called the tricuspid
valve. This valve prevents blood from going
back into the right atrium.
• From the right ventricle the blood will exit
the heart through the pulmonary valve into
the pulmonary arteries into the lungs.
• Once the blood is in the lungs it becomes
oxygenated and will return back to the heart
though the pulmonary veins.
• Each lung has two pulmonary veins that
bring blood to the left atrium.
• Blood exits the left atrium and passes
through the mitral valve, (which is a
bicuspid), into the left ventricle.
• From the left ventricle blood will pass
through the aortic valve into the aorta.
• The aortic valve prevents blood from flowing
back into the heart.
• The aortic arch will then send blood to the
rest of the body.
– Arteries = away from heart
Veins = to heart
Heart Actions
• Systole- heart contraction
• Diastole- heart relaxation
• Sinoatrial (SA) and Atrioventricular (AV)
Nodes are specialized masses of cells that are
responsible for initiating the myocardium of
the heart to contract.
• This information is passed through the
Purkinje Fibers of the heart and cause the
heart to contract.
Gases are Exchanged in Capillary Beds
• Oxygenated blood leaves the heart and
returns through this process:
–
–
–
–
–
–
Arteries
Arterioles
Capillaries
Venules
Veins
p. 339
Factors that influence Blood
Pressure
Stroke volume – the total blood discharged from
the left ventricle with each contraction (usually
around 70mL)
Heart Rate – the rate at which your heart beats.
(usually measured at beats/min)
Cardiac output = stroke volume x heart rate
if stroke volume = 70 ml
and heart rate is 72 beats/min
CO = 70 x 72 = 5,040 mL/min
BP varies with Cardiac Output
• If the stroke volume or heart rate increases,
the cardiac output will increase.
• Blood pressure is directly proportional to
cardiac output
• Meaning, as CO increase, BP increases
• As CO decreases, BP decreases
Blood Volume
• Blood volume – is the total amount of blood in
the vascular system
• Blood volume varies depending on age,
gender, and weight, but is usually around 5
liters
• Blood volume and blood pressure are also
directly proportional. As BV increases, BP
increases, if BV decreases, BP decreases
Peripheral Resistance
• Peripheral Resistance – friction between the
walls of blood vessels and the blood.
• Periphereal resistance is inversely
proportional to blood pressure.
• This means as the blood vessels get smaller,
vasoconstriction, blood pressure increases.
• As peripheral resistance decreases,
vasodialation, blood pressure decreases
Blood Viscosity
• Ease at which blood flows.
• Blood cells and plasma proteins increase
blood viscosity
• Blood viscosity is directly proportional,
meaning that as viscosity increases, blood
pressure increases
• As blood viscosity decreases, blood
pressure decreases