Functions of the Circulatory System Brings blood containing
oxygen, nutrients, and hormones to cells Transports CO 2 and other
wastes away from cells
Slide 5
Fights infection Regulates body temperature Helps stabilize pH
and ionic concentration of body fluids. Functions
Slide 6
Circulatory System Components Heart Blood Vessels Arteries
Veins Capillaries
Slide 7
The Heart A muscular pump Moves blood through the body Is
suspended in the pericardial sac Composed of four chambers Divided
into right and left halves Made up of cardiac muscle cells Aorta
Left pulmonary artery Left atrium Left pulmonary veins Left
ventricle Superior vena cava Right pulmonary veins Right atrium
Right ventricle Inferior vena cava
Slide 8
Pericardium Protective sac of connective tissue Surrounds the
heart Filled with fluid
Slide 9
Myocardium The muscle of the heart Strong and thick Composed of
spontaneously contracting cardiac muscle fibers Can conduct
electricity like nerves Its blood supply comes from the coronary
arteries Myocardium (heart muscle) shown in red Epicardium (Outer
surface of myocardium) Endocardium (Inner surface of
myocardium)
Slide 10
Structures of the Heart Chambers Atria- (2) upper chambers Thin
walled Receive blood from veins Send blood to ventricles
Ventricles- (2) lower chambers Thick walled Receive blood from
atria Pump blood out through arteries Septum Wall that divides
heart into right and left halves Septum Pulmonary valve Right
atrium Tricuspid valve Right ventricle Left atrium Aortic valve
Mitral valve Left ventricle
Slide 11
Structures of the Heart Valves Prevent backflow of blood Keep
blood moving in one direction Located between the chambers Located
at the junctions of the artery and chamber Tricuspid valve
Pulmonary veins Mitral valve Left atrium Pulmonary valve Aortic
valve Right atrium Valves seen from above Chordea tendinea
Pulmonary valve
Slide 12
Structures of the Heart Chordae tendinease Heart strings
Cord-like tendons Connect papillary muscles to tricuspid and mitral
valves Prevent inversion of valve Papillary muscles Small muscles
that anchor the cords Papillary muscle
Slide 13
aortic valve left common carotid artery left subclavian artery
brachiocephalic artery right pulmonary artery septum left pulmonary
artery aorta pulmonary trunk left pulmonary veins left atrium
(auricle) mitral valve pulmonary valve papillary muscle left
ventricle right pulmonary veins superior vena cava right atrium
tricuspid valve right ventricle inferior vena cava 2006
Merriam-Webster, Inc. Structures of the Heart 6 11 10 14 1 9 8 7 5
3 4 2 17 12 16 13 15
Slide 14
Cardiac Cycle Refers to all of the events from the beginning of
one heart beat to the beginning of the next heart beat When cardiac
muscle contracts it does so as a single unit, creating a heart beat
One heartbeat - a cardiac cycle - consists of two parts called
systole and diastole
Slide 15
Cardiac Cycle Diastole is the period of time when the heart
relaxes after contraction Oxygenated blood from the lungs fills the
left atrium Deoxygenated blood from other parts of the body fills
the right atrium. At the end of the diastole, the atria contract,
starting the Systole
Slide 16
Cardiac Cycle Atrial systole is the contraction of the heart
muscle of the left and right atria. Both atria contract at the same
time, sending blood into the corresponding ventricle Ventricular
systole is the contraction of the muscles of the left and right
ventricles, which contract at the same time. The term systole is
synonymous with contraction of a muscle.
Slide 17
Cardiac Cycle During systole the ventricles contract, forcing
the blood into the pulmonary artery to be re-oxygenated in the
lungs, and into the aorta for systemic distribution of oxygenated
blood
Slide 18
Two normal heart sounds with each heart beat described as a..
Heart Sounds Lub- sound- due to closure of the atrioventricular
valves (mitral and tricuspid) Dub- sound- due to closure of the
aortic valve and pulmonary valve
Slide 19
Cardiac Cycle Heart Rate - count of each heart beat On average,
a heart beats 72 times a minute when at rest Usually it is
calculated as number of contractions of heart (heart beats) in one
minute and expressed as "beats per minute" (bpm). The pulse is the
most straightforward way of measuring the heart rate Heart rate is
controlled by nervous system Hearse on an emergency
Slide 20
Cardiac Cycle Resting heart rate can be significantly lower in
athletes Sympathetic division increases heart rate Parasympathetic
division decreases heart rate Heart rate increases when more food
and oxygen are needed by the cells, or when under stress
Slide 21
Cardiac Cycle An electrocardiogram abbreviated as EKG or ECG is
a test that measures the electrical activity of the heartbeat or
one cardiac cycle.
Slide 22
Cardiac Conduction System Why dont the atria and ventricles
contract at the same time? Inefficient. Blood would not be moved in
one direction, some would flow backwards
Slide 23
Includes: SA node AV node Bundle of His Purkinje fibers
Slide 24
Cardiac Conduction System Sinoatrial Node (SA node) Located
high on the right atrium. Pacemaker of the heart. Causes the wave
of contractions in the atria. Sending blood into the
ventricles
Slide 25
Cardiac Conduction System Atrioventricular Node (AV node)
Located in the interatrial septum close to the tricuspid valve
Carries the electrical impulse from the SA node to fiber bundles in
the ventricles. This causes the ventricles to contract The location
of nerve fiber bundles cause the ventricles to contract from the
apex (bottom) up squeezing blood up and out
Slide 26
Pathway of Circulation Oxygen-poor blood draining from the body
through veins into the superior and inferior vena cava flows to the
right atrium, through the tricuspid valve, and into the right
ventricle. As the right ventricle contracts, oxygen-poor blood
passes through the pulmonary valve into the pulmonary arteries and
on to the lungs to receive oxygen.
Slide 27
Oxygen-rich blood from the lungs enters the heart through the
pulmonary veins, passing into the left atrium. Then through the
mitral valve to the left ventricle. Contraction of the left
ventricle forces blood through the aortic valve into the aorta.
Various arteries branch off from the aorta to supply blood to all
parts of the body.
Slide 28
Arteries branch into smaller and smaller vessels (arterioles)
They eventually become capillaries, which supply blood to all body
parts Capillaries merge into (venuoles) which join into veins and
carry blood back to the heart. Nutrients pass into tissues Waste
products filter back Blood pumped out of heart into arteries, which
branch into smaller and smaller vessels until blood flows into
capillaries Blood returns to the heart through the veins Heart
Capillary network
Slide 29
Pathway of Circulation
Slide 30
14 9 11 10 8 6 13 12 6 5 4 3 2 1 1 16 15 14 7 And so on It
takes about 1 min. for blood to make 1 complete cycle
Slide 31
Pulmonary Circuit Systemic Circuit Lung Pulmonary vein Aorta
Left atrium Left ventricle Pulmonary artery Right atrium Right
ventricle Vena cava oxygen-poor blood oxygen-rich blood
Cardiovascular Circuits
Slide 32
Pulmonary Circulation Takes place on the right side of the
heart. Pumps blood low in oxygen to the lungs to pick up oxygen and
return to heart
Slide 33
Systemic Circulation Takes place on left side of heart
Oxygenated blood is pumped to the body cells thru the aorta and
other arteries Blood low in oxygen returns to the heart
Slide 34
Coronary Circulation Although blood fills the chambers of the
heart, the muscle tissue of the heart is so thick that it requires
coronary blood vessels to deliver blood deep into the myocardium.
The coronary circulation consists of the blood vessels that supply
blood to, and remove blood from the heart muscle itself.
Slide 35
The vessels that supply blood high in oxygen to the myocardium
are known as coronary arteries.
Slide 36
Blood Vessels Form a closed circuit of tubes that carry blood
throughout the body Laid end to end, the blood vessels in an
average human body will stretch approximately 62,000 miles2.5 times
around the earth
Slide 37
Blood Vessels Have characteristic features Are distinguished by
size, tissue layers and direction of blood flow
Slide 38
Blood Vessels Arteries Receive blood from ventricles Take blood
away from the heart Usually carry oxygenated blood Thickest vessel
walls Withstand greater blood pressure Are very elastic Connect to
capillaries Aorta is the largest artery
Slide 39
Blood Vessels Veins Transport blood away from capillaries Carry
blood toward heart Take blood to atria Have valves Thinner vessel
walls with less smooth muscles than arteries Can stretch a great
deal Have larger diameters Usually carry de-oxygenated blood Vena
cava is the largest vein
Slide 40
Blood Vessels The contraction of muscles compressing veins
helps push blood up through the leg veins back to the heart. The
valves allow the blood to flow towards the heart only. Calf muscle
relaxed Calf muscle contracts Muscle squeezes veins Veins
constrict; blood moves; valves open Veins dialated; blood still;
valves closed Valves OPEN Valves CLOSED
Slide 41
Blood Vessels Capillaries Smallest of blood vessels Only one
cell thick (epithelial cell) Connect arteries to veins Bring oxygen
and nutrients to cells Removes CO 2, urea, and other wastes from
cells Where blood is under low pressure and moving slowly
Slide 42
A network of capillaries runs close to the cells in every part
of the body. The capillaries have very thin walls which allows
nutrients to diffuse through into the tissues and waste products to
filter back into the capillaries. Arteriole Venule Tissue cells
Vein Artery capillaries Capillaries
Slide 43
CB CB O L M O PO AD R I V SE OS NS E OL FS
Slide 44
Blood Pressure Blood pressure refers to the force exerted by
circulating blood on the walls of blood vessels The pressure of the
circulating blood decreases as blood moves through arteries,
arterioles, capillaries, venules, and veins
Slide 45
Blood Pressure Blood pressure is most commonly measured via a
sphygmomanometer (blood pressure cuff) It uses the height of a
column of mercury to reflect the circulating pressure Average blood
pressure for an adult is 120/80
Slide 46
Blood Pressure Systolic pressure is defined as the maximum
pressure in the arteries exerted during ventricular contraction
(which occurs near the beginning of the cardiac cycle) Diastolic
pressure is the minimum pressure exerted when ventricles relax and
fill (at the resting phase or end of the cardiac cycle) Blood
pressure readings = S/D
Slide 47
Blood Pressure Pressure waves move through the blood vessels A
person's pulse is the throbbing of their arteries as an effect of
the pressure waves (heart beat) Pulse is used to denote the
frequency of the heart beat It can be felt at neck, wrist, and
other places Pulse is usually measured in beats per minute.. In
most people, the pulse is an accurate measure of heart rate.
Slide 48
Blood Pressure Vasoconstriction is narrowing of a blood vessel.
When a blood vessel constricts, the flow of blood is restricted or
slowed. Blood pressure will increase Vasodilatation is where blood
vessels in the body become wider following relaxation of smooth
muscle in vessel wall. This will reduce blood pressure - since
there is more room for the blood. and
Slide 49
Blood The life stream of the body, affecting every cell and
system we have. The blood is an accumulation of many different
elements, each working in a specific way to keep us alive.
Slide 50
Blood A circulating connective tissue consisting of several
types of cells suspended in a fluid medium known as plasma.
Slide 51
Functions of blood: Supply oxygen to tissues Supply nutrients
such as glucose, amino acids and fatty acids to tissues Removal of
wastes such as CO 2, urea and lactic acid from tissues
Immunological functions, including circulation of white cells, and
detection of foreign material by antibodies
Slide 52
Functions of blood continued: Messenger functions, including
transport of hormones and signaling of tissue Coagulation, part of
body's self-repair mechanism Regulation of core body temperature
Regulation of body pH and ion concentrations
Slide 53
What percent of your body is blood? How much blood do we
contain? On average 4-6 liters We contain about a pint of blood for
every 15 pounds of body weight Composition of Blood: What percent
of your blood is cellular? What percent of your blood is plasma? 8%
45% 55%
Slide 54
Blood What is plasma? A clear, straw colored fluid What percent
of plasma is water? Whats in plasma? Dissolved gasses Vitamins
Minerals Salts Nutrients Enzymes Hormones Waste products Plasma
proteins 90% Buffy coat leukocytes and platelets (