Cardiovascular System (CVS)
Cardiac
(heart)
Right sided:
(volume pump)
Left sided:
(Pressure pump)
Vascular
-
Arteries
Arterioles
Capillaries
Venules
Veins
Functions of Cardiovascular System
I. Primary (main) Function of the Heart:
♥ Acts as a muscular pump:
in order to maintain adequate level of blood flow
throughout CVS by pumping blood under press into
vascular system.
♥ Responsible for the mass movement of fluid in
body.
Functions of Cardiovascular System
II. Secondary functions:
1. Transportation:
•
•
•
•
Delivers O2 to tissues, & brings back CO2 to lungs.
Carries absorbed digestion products to liver &
tissues.
Carries metabolic wastes to kidneys to be excreted.
Distribution of body fluids.
Functions of Cardiovascular System
II. Secondary functions:
2. Regulation:
•
•
•
•
Hormonal: carries hormones to target tissues to
produce their effects.
Immune: carries antibodies, leukocytes (WBCs),
cytokines, & complement to aid body defense
mechanism against pathogens.
Protection: carries platelets, & clotting factors to aid
protection of the body in blood clotting mechanism.
Temperature: helps in regulation of body
temperature, by diverting blood to cool or warm the
body.
Anatomy of the Heart
Position:
located behind
sternum.


Hollow, muscular organ.
Anatomy of the Heart
♥ Consists of 2 separate pumps that maintain
unidirectional flow of blood; the Lt & Rt hts.
♥ Left heart pumps oxygenated blood  Systemic
circulation.
♥ Right heart pumps deoxygenated blood  Pulmonary
circulation.
♥ Each pump contains 2 chambers: an atrium &
a ventricle.
♥ 2 Atria:
■
■
Chambers of the Heart
♥ 2 Ventricles:
Thin-walled chambers.
Receive blood returning to
heart.
■
■
■
Thicker, muscular walls.
Pump blood from heart.
Each has same capacity
& pumps same volume of
bl in a given period of time.
Chambers of the Heart
♥ Atria & ventricles are separated into 2 functional units
by a sheet of fibrous connective tissue, which gives
attachment to the valves.
Valves of the Heart
♥ 2 Atrioventricular (AV)
valves:
■ One way valves.
■ Allow bl to flow from
atria into ventricles.
■ Tricuspid (Rt) & Mitral (Lt).
♥ 2 Semilunar valves :
■ One way valves.
■ At origin of pulmonary artery
& aorta.
■ Pulmonary (Rt) & Aortic (Lt).
■ Open during ventricular
contraction.
Valves of the Heart: Remember
■ Vs are at entrance & exit
of each ventricle.
■ Vs allow bl to flow in only
ONE direction.
■ When AV-vs open, semilunar-vs
close & vice versa.
■ Opening & closing of
vs occur as a result of press
differences.
■ AV cusps are held by chordae
tendineae to papillary muscles.
Atrioventricular & Semilunar Valves
Types of Circulations
Pulmonary and Systemic Circulations
■ Pulmonary circulation:
– Bl pumped from RV
through the lungs & back
to the ht.
■ Systemic circulation:
– Oxygen-rich bl pumped to
all organ systems to supply
nutrients from LV
■ Rate of bl flow through
systemic circulation = flow
rate through pulmonary
circulation.
Pulmonary Circulation
• Moves blood to and from the lungs
• Pulmonary trunk
– Arises from right ventricle
• Pulmonary arteries
– Branches of pulmonary trunk which project to
lungs
• Pulmonary veins
– Exit each lung and enter left atrium
Systemic Circulation: Arteries
• Aorta
– From which all arteries are derived either directly
or indirectly
– Parts
• Ascending, descending, thoracic, abdominal
• Coronary arteries
– Supply the heart
Systemic Circulation: Veins
• Return blood from body to right atrium
• Major veins
– Coronary sinus (heart)
– Superior vena cava (head, neck, thorax, upper
limbs)
– Inferior vena cava (abdomen, pelvis, lower
limbs)
• Types of veins
– Superficial, deep, sinuses
Fetal Circulation
Fetal Circulation
•No circulation to lungs
•Foramen ovale
•Ductus arteriosum
•Circulation must go to placenta
•Umbilical aa., vv.
Larry M. Frolich, Ph.D.,Human Anatomy
Heart Walls: 3 Distinct Layers
1. Endocardium:
the innermost layer of the ht.
2. Myocardium:
the thickest main layer,
consists of cardiac ms.
3. Pericardium (epicardium):
the thin, outer covering or
external membrane around
the ht.
Adult remnants of fetal circulation
Adult
Fetus
Fossa ovale
Foramen ovale
Ligamentum arteriosum
Ductus arteriosus
Medial umbilical ligaments
Umbilical aa.(within fetus)
Round ligament
(ligamentum teres) of liver
Ligamentum venosum
Umbilical v.(within fetus)
Medial umbilical ligament
Umbilical cord (leaving fetus)
Ductus venosus
Physiology of Cardiac Muscle
■ Cardiac muscle tissue forms 2 functional syncytia:

atria, & ventricles.
The heart is composed of 2 major types of cardiac
muscle:
1: Contractile cells.
2: Autorhythmic (or automatic) cells.
Contractile cells: Contract when stimulated, in same
way as skeletal ms except for longer duration.
Heart : Conducting Tissues
1.
2.
3.
4.
5.
6.
Sinoatrial (SA) node.
Internodal pathways.
Atrioventricular (AV) node.
Bundle of His.
Rt & Lt bundle branches.
Purkinje fibers.
Heart : Conducting Tissues
♥ Conduction pathway:
–
–
–
–
–
–
Sinoatrial (SA) node.
Internodal pathways.
Atrioventricular (AV) node.
Bundle of His.
Rt & Lt bundle branches.
Purkinje fibers.
♥ Stimulation of Purkinje
fibers cause both ventricles
to contract simultaneously.
Heart : Conducting Tissues
■ SA- node & to a lesser extent AVnode contain small round cells
called ‘P cells’ which are probably
the actual pacemaker cells.
■ At AV- node, very small no. of
intercalated discs & gap junctions
 delay transmission of impulse.
Cardiac Cycle
• Heart is two pumps that work together, right and
left half
• Repetitive contraction (systole) and relaxation
(diastole) of heart chambers
• Blood moves through circulatory system from
areas of higher to lower pressure.
– Contraction of heart produces the pressure
Regulation of the Heart
• Intrinsic regulation: Results from normal functional
characteristics, not on neural or hormonal regulation
– Starling’s law of the heart
• Extrinsic regulation: Involves neural and hormonal
control
– Parasympathetic stimulation
• Supplied by vagus nerve, decreases heart rate, acetylcholine secreted
– Sympathetic stimulation
• Supplied by cardiac nerves, increases heart rate and force of
contraction, epinephrine and norepinephrine released
Cardiac Innervations
■ Autonomic Nervous System:
I: Sympathetic Nervous System division.
II: Parasympathetic Nervous System division.
Cardiac Innervations
I: Sympathetic Nervous
System:
■ Sympathetic nerves that
reaches heart originates from
POSTGANGLIONIC FIBERS
(upper thoracic, paravertebral, ganglia) 
releases NORADRENALINE.
■ Mainly supplies:
– SA-node,
– Atrial myocardium,
– AV-node,
– Ventricular myocardium.
Cardiac Innervations
II: Parasympathetic Nervous
System:
■ Parasympathetic nerve (vagus)
that reaches ht originates from
PREGANGLIONIC FIBERS (T1
to T5) 
releases ACETYLCHOLINE.
■ Mainly supplies:
– SA-node,
– Atrial myocardium,
– AV-node.
Heart Sounds
• First heart sound or “lubb”
– Atrioventricular valves and surrounding
fluid vibrations as valves close at
beginning of ventricular systole
• Second heart sound or “dupp”
– Results from closure of aortic and
pulmonary semilunar valves at
beginning of ventricular diastole, lasts
longer
• Third heart sound (occasional)
– Caused by turbulent blood flow into
ventricles and detected near end of first
one-third of diastole
Heart Chambers and Valves
Larry M. Frolich, Ph.D.,Human Anatomy
Heart Valves: Lub*-Dub**
•
*Tricuspid Valve: Right AV valve
–
–
–
–
–
–
•
3 Cusps (flaps) made of endocardium and CT
Cusps anchored in Rt. Ventricle by Chordae Tendinae
Chordae Tendinae prevent inversion of cusps into atrium
Flow of blood pushes cusps open
When ventricle in diastole (relaxed), cusps hang limp in ventricle
Ventricular contraction increases pressure and forces cusps closed
*Bicuspid (Mitral) Valve: Left AV valve
– 2 cusps anchored in Lft. Ventricle by chordae tendinae
– Functions same as Rt. AV valve
•
**Semilunar valves: prevents backflow in large arteries
– Pulmonary Semilunar Valve: Rt Ventricle and Pulmonary Trunk
– Aortic Semilunar Valve: Left Ventricle and Aorta
– 3 cusps: blood rushes past they’re flattened, as it settles they’re pushed
down (valve closed)
Larry M. Frolich, Ph.D.,Human Anatomy
Location of Heart in Thorax
pg 523
Larry M. Frolich, Ph.D.,Human Anatomy
Location of Heart in Chest
•
•
•
•
•
•
•
Oblique Position
Apex = Left of Midline (5th ICS), Anterior to rest of heart
Base (posterior surface) sits on vertebral column
Superior Right = 3rd Costal Cartilage, 1” right midsternum
Superior Left = 2nd Costal Cartilage, 1” left midsternum
Inferior Right = 6th Costal Cartilage, 1” right midsternum
Inferior Left = 5th Intercostal Space at Midclavicular line
Larry M. Frolich, Ph.D.,Human Anatomy
Heart Innervation
• Heart receives visceral
motor innervation
– Sympathetic (speeds up)
– Parasympathetic (slows
down)
p. 534
Larry M. Frolich, Ph.D.,Human Anatomy
Fetal Circulation
•No circulation to lungs
•Foramen ovale
•Ductus arteriosum
•Circulation must go to placenta
•Umbilical aa., vv.
Larry M. Frolich, Ph.D.,Human Anatomy
Adult remnants of fetal circulation
Adult
Fetus
Fossa ovale
Foramen ovale
Ligamentum arteriosum
Ductus arteriosus
Medial umbilical ligaments
Umbilical aa.(within fetus)
Round ligament
(ligamentum teres) of liver
Ligamentum venosum
Umbilical v.(within fetus)
Medial umbilical ligament
Umbilical cord (leaving fetus)
Ductus venosus
Coronary Arteries
The heart muscle, like every other organ or tissue in your body, needs oxygenrich blood to survive. Blood is supplied to the heart by its own vascular
system, called coronary circulation.
The aorta (the main blood supplier to the body) branches off into two main
coronary blood vessels (also called arteries). These coronary arteries
branch off into smaller arteries, which supply oxygen-rich blood to the
entire heart muscle.
The right coronary artery supplies blood mainly to the right side of the heart.
The right side of the heart is smaller because it pumps blood only to the
lungs.
The left coronary artery, which branches into the left anterior descending
artery and the circumflex artery, supplies blood to the left side of the
heart. The left side of the heart is larger and more muscular because it
pumps blood to the rest of the body.
Conductive system of the heart
Electrical impulses from your heart muscle (the
myocardium) cause your heart to beat (contract).
This electrical signal begins in the sinoatrial (SA)
node, located at the top of the right atrium. The SA
node is sometimes called the heart's "natural
pacemaker." When an electrical impulse is released
from this natural pacemaker, it causes the atria to
contract. The signal then passes through the
atrioventricular (AV) node. The AV node checks the
signal and sends it through the muscle fibers of the
ventricles, causing them to contract. The SA node
sends electrical impulses at a certain rate, but your
heart rate may still change depending on physical
demands, stress, or hormonal factors.