Definitions:
Heart: Is a pumping machine
Atrium: one of the four chambers from which the heart is composed,
they are two and act to receive blood from the veins, and structurally
are thinner than ventricles.
Ventricle: Is the other two chambers of the heart that act to force
blood out of the heart into the arteries.
Arteries: Strong, elastic vessels that are adapted for carrying the
blood away from the heart under relatively high pressure.
Arterioles: The subdivision of arteries into thinner tubes and fine
branches. Are the microscopic continuations of the arteries.
Veins: Are tubes that carry the blood back to the atria, veins are
thinner, less elastic, have less smooth muscles than arteries.
Capillaries: Are the smallest blood vessels, they form connections
between the smallest arterioles and the smallest venules. They
distribute in all body tissues but vary in the density, ex: muscle
tissues are richly supplied with capillaries because they need high
amount of oxygen and nutrients.
Venules: Are microscopic vessels that continue from the capillaries
and merge to form veins.
Aorta: Is the largest artery in the body, it extends upward from the
left ventricle and then descend and divided into many subdivisions to
distribute blood through out the body.
Coronary Arteries: Is the first two right and left branches of the
aorta that act to feed the heart with fresh oxygen to act properly.
Heart Sound: It is the sound associated with the heartbeat can be
heard with the stethoscope and are described as lub dup sound,
these sounds are due to the vibrations in the cardiac tissues and the
opening and closing of the valves. Lup sound occurs during the
ventricular contraction, the bi and tri cuspid are closed, Dup sound
occurs during the ventricular relaxation.
Heart Action: The action of the heart is to create blood pressure by
forcing the blood into the artery, it also determines how much blood
will enter to the arterial system with each ventricular contraction,
and also determine the rate of fluid output.
Vasoconstriction: Impulses reaching the smooth muscle causing
fibers to contract in order to reduce the diameter of the vessel. This
constriction happened in order to push blood into the body tissues.
Vasodilatation: If the impulses were inhibited, then the vascular
smooth muscles relax and the diameter of the vessels are increased.
Stroke Volume: It is the volume of blood discharged from the
ventricle with each contraction, equals about 70 ml.
Cardiac output: The volume of blood discharged per minute, it is
calculated by multiplying the stroke volume by the heart rate in
beats per minute. (Cardiac output = stroke volume x heart rate).
Example, if the stroke volume is 70 ml and the heart rate is 72 beats
per minute, the cardiac out put is 5040 ml per minute.
Blood Volume: Is equal to the sum of the blood cells and plasma
volumes in the cardiovascular system, and it is affected by age and
body size. In adults it is usually about 5 liters.
Systolic pressure: Is the maximum pressure achieved during
ventricular contraction
Diastolic pressure: In which ventricles relaxes, the arterial blood
pressure drops, the lowest pressure that remains in the arteries
before the next ventricular contraction.
Peripheral Resistance: It is the frictional force between the blood
and the walls of the blood vessels, which hinders the blood flow. If
the arteriolar peripheral Resistance increases the blood retuns to the
arteries causing to increase blood pressure and vise versa.
Action Potential: A large and temporary change in the voltage across
the membrane of neuron associated with the reversal of polarity
caused by the sudden influx of sodium ions.
Arteriosclerosis: It is the hardening and loss of elasticity of the
blood vessels, the incidence increase with age.
Atherosclerosis: Athero related to the presence of cholesterol and
fats, sclerosis means hardening so Atherosclerosis is a combination
of changes in the arteries consisting of the accumulation of lipids,
complex carbohydrate and calcium.
Interstitial fluid: The fluid circulates in the interstitial spaces
between cells. It is an intercellular fluid, this space provide the
medium through which oxygen and nutrients can pass to the cell
from the capillaries and waste products can be carried away.
Renin: Hormone released from juxtaglomerular apparatus in the
kidney, which as enzyme converting plasma protein angiotensinogen
to angiotensin, and its release is affected by blood volume.
Heart: Is a pumping machine
Atrium: one of the four chambers from which the heart is composed,
they are two and act to receive blood from the veins, and structurally
are thinner than ventricles.
Ventricle: Is the other two chambers of the heart that act to force
blood out of the heart into the arteries.
Arteries: Strong, elastic vessels that are adapted for carrying the
blood away from the heart under relatively high pressure.
Arterioles: The subdivision of arteries into thinner tubes and fine
branches. Are the microscopic continuations of the arteries.
Veins: Are tubes that carry the blood back to the atria, veins are
thinner, less elastic, have less smooth muscles than arteries.
Capillaries: Are the smallest blood vessels, they form connections
between the smallest arterioles and the smallest venules. They
distribute in all body tissues but vary in the density, ex: muscle
tissues are richly supplied with capillaries because they need high
amount of oxygen and nutrients.
Venules: Are microscopic vessels that continue from the capillaries
and merge to form veins.
Aorta: Is the largest artery in the body, it extends upward from the
left ventricle and then descend and divided into many subdivisions to
distribute blood through out the body.
Coronary Arteries: Is the first two right and left branches of the
aorta that act to feed the heart with fresh oxygen to act properly.
Heart Sound: It is the sound associated with the heartbeat can be
heard with the stethoscope and are described as lub dup sound,
these sounds are due to the vibrations in the cardiac tissues and the
opening and closing of the valves. Lup sound occurs during the
ventricular contraction, the bi and tri cuspid are closed, Dup sound
occurs during the ventricular relaxation.
Heart Action: The action of the heart is to create blood pressure by
forcing the blood into the artery, it also determines how much blood
will enter to the arterial system with each ventricular contraction,
and also determine the rate of fluid output.
Vasoconstriction: Impulses reaching the smooth muscle causing
fibers to contract in order to reduce the diameter of the vessel. This
constriction happened in order to push blood into the body tissues.
Vasodilatation: If the impulses were inhibited, then the vascular
smooth muscles relax and the diameter of the vessels are increased.
Stroke Volume: It is the volume of blood discharged from the
ventricle with each contraction, equals about 70 ml.
Cardiac output: The volume of blood discharged per minute, it is
calculated by multiplying the stroke volume by the heart rate in
beats per minute. (Cardiac output = stroke volume x heart rate).
Example, if the stroke volume is 70 ml and the heart rate is 72 beats
per minute, the cardiac out put is 5040 ml per minute.
Blood Volume: Is equal to the sum of the blood cells and plasma
volumes in the cardiovascular system, and it is affected by age and
body size. In adults it is usually about 5 liters.
Systolic pressure: Is the maximum pressure achieved during
ventricular contraction
Diastolic pressure: In which ventricles relaxes, the arterial blood
pressure drops, the lowest pressure that remains in the arteries
before the next ventricular contraction.
Peripheral Resistance: It is the frictional force between the blood
and the walls of the blood vessels, which hinders the blood flow. If
the arteriolar peripheral Resistance increases the blood retuns to the
arteries causing to increase blood pressure and vise versa.
Action Potential: A large and temporary change in the voltage across
the membrane of neuron associated with the reversal of polarity
caused by the sudden influx of sodium ions.
Arteriosclerosis: It is the hardening and loss of elasticity of the
blood vessels, the incidence increase with age.
Atherosclerosis: Athero related to the presence of cholesterol and
fats, sclerosis means hardening so Atherosclerosis is a combination
of changes in the arteries consisting of the accumulation of lipids,
complex carbohydrate and calcium.
Interstitial fluid: The fluid circulates in the interstitial spaces
between cells. It is an intercellular fluid, this space provide the
medium through which oxygen and nutrients can pass to the cell
from the capillaries and waste products can be carried away.
Renin: Hormone released from juxtaglomerular apparatus in the
kidney, which as enzyme converting plasma protein angiotensinogen
to angiotensin, and its release is affected by blood volume.
Cardiovascular Diseases
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