Download OVER VIEW OF CIRCULATORY SYSTEM

OVER VIEW OF CVS
LEARNING OBJECTIVES
At the end of the lecture the student should be able
to know
• About organization of cardio vascular system
• About Components of cardio vascular system
• About location, external and internal structure
of heart
• About different chambers and valve of the heart
• About two different circulatory circuits; he
should understands the working of these
circuits
• About the structure of different vessels
CIRCULATORY SYSTEM
• Known as cardiovascular system
A closed system of the heart and blood vessels
• Circulates blood through out the body
Components
• Heart -main pumping organ of body
• Vessels - carry the blood towards and away from heart
– Arteries
– Veins
– capillaries
– lymphatics
FUNCTIONS OF CARDIOVASCULAR
SYSTEM
– Circulate blood throughout entire
body for
– Transport of oxygen to cells
– Transport of CO2 away from cells
– Transport of nutrients (glucose) to
cells
– Movement of immune system
components (cells, antibodies)
– Transport of endocrine gland
secretions
ORGANIZATION OF CVS
– Heart is the central organ for
pumping
– The cardiovascular system is
divided into two circuits
– Pulmonary circuit
– blood to and from the lungs
– Systemic circuit
– blood to and from the rest of the
body
– Vessels carry the blood through
the circuits
– Arteries carry blood away from
the heart
– Veins carry blood to the heart
– Capillaries permit exchange
OVER VIEW OF HEART
– Pumping station of the body
– Hollow muscular organ
– About the size of the fist
• Location
– In middle mediastinum
– Within pericardial cavity
– Between lungs
– Posterior to sternum
– Anterior to vertebral column
– Pointed apex directed to left
• Covered by pericardium
• Has 3 layers in wall
• Has 4 chambers
• Has four valves
• Supplied by coronary arteries
• Connected to pulmonary and systemic circuit by large
vessels
• Has specialized, autonomous conducting system
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OVER VIEW OF PERICARDIUM
A double-walled sac around the heart
composed of:
A superficial fibrous pericardium
A deep two-layer serous pericardium
The parietal layer lines the internal
surface of the fibrous pericardium
The visceral layer or epicardium lines the surface of the
heart
– They are separated by the fluid-filled pericardial cavity
OVER VIEW OF HEART WALL
– Three layers
• Epicardium
– Outside layer
– This layer is the parietal pericardium
– Connective tissuelayer
• Myocardium
– Middle layer
– Mostly cardiac muscle
• Endocardium
– Inner layer
EXTERNAL HEART ANATOMY
ANTERIOR VIEW
POSTERIOR VIEW
OVER VIEW OF HEART CHAMBERS
• Right and left side act as separate
pumps
• Four chambers
Atria
• Receiving and upper chambers
– Right atrium
– Left atrium
Ventricles
• Discharging and lower
• chambers
– Right ventricle
– Left ventricle
OVER VIEW OF ATRIA
• Receiving chambers of the heart
• Each atrium has a protruding auricle
• Pectinate muscles mark atrial walls
• Collect blood
• Right atria from systemic circuit
through
– Superior and inferior venae
cavae
– Coronary sinus
• Left atria from pulmonary circuit
through
– Pulmonary veins
OVER VIEW OF VENTRICLES
• Discharging chambers of the heart
• Papillary muscles and trabeculae
carneae muscles mark ventricular
walls
• Pumps blood
– Right ventricle into the
pulmonary trunk
– Left ventricle into the aorta
OVER VIEW OF HEART VALVES
• Allow blood to flow in only One direction
• Four valves
• Atrioventricular valves
– between atria and ventricles
• Bicuspid valve (left)
• Tricuspid valve (right)
• Semilunar valves
– between ventricle and artery
• Pulmonary between right
ventricle and pulmonary trunk
• Aortic between left ventricle and aorta
THE HEART: ASSOCIATED GREAT VESSELS
 Aorta
 Leaves left ventricle
 Pulmonary arteries
 Leave right ventricle
 Vena cava
 Enters right atrium
 Pulmonary veins (four)
 Enter left atrium
OVER VIEW OF CORONARY CIRCULATION
 Blood in the heart chambers does not
nourish the myocardium
 The heart has its own nourishing
circulatory system
 Coronary arteries
 Cardiac veins
 Blood empties into the right atrium
via the coronary sinus
OVER VIEW OF CONDUCTING SYSTEM
 Intrinsic conduction system
(nodal system)
 Heart muscle cells contract,
without nerve impulses, in a
regular, continuous way
 Special tissue sets the pace
 Sinoatrial node (right
atrium)
 Pacemaker
 Atrioventricular node
 (junction of r&l atria
and ventricles)
 Atrioventricular bundle (Bundle of His)
 Bundle branches (right and left)
 Purkinje fibers
PULMONARY CIRCULATION PATHWAY
• Deoxygenated blood from body  vena cava 
Right atrium tricuspid valve  right ventricle
pulmonary semilunar valve pulmonary arteries
 lungs
SYSTEMIC CIRCULATION PATHWAY
• Oxygenated blood from lungspulmonary veins  left
atriumbicuspid valve  left ventricle  aortic semilunar
valve aortastemic circulation
Our circulatory system is a double circulatory system.
This means it has two parts
Lungs
the right side of the
the left side of the
system
system
deals with
deals with
deoxygenated
oxygenated blood.
blood.
Body cells
OVER VIEW OF VASCULAR
SYSTEM
• BLOOD VESSELS
• LYMPHATICS
• Tubular structures that carry
blood to and from the heart
• Arteries
• Arterioles
• Capillaries
• Venules
• Veins
OVER VIEW OF BLOOD VESSELS
LAYERS OF VESSEL WALL
• Tunica externa
– Outermost layer
– CT w/elastin and collagen
– Strengthens, Anchors
• Tunica media
– Middle layer
– Circular Smooth Muscle
– Vaso-constriction/dilation
• Tunica intima
– Innermost layer
– Endothelium
– Minimize friction
• Lumen
DIF F E R E NC E S B E TWE E N B L OOD
VE S S E L T Y P E S
A rteries
Veins
Direc tion of flow
B lood Away from Heart
B lood to Heart
P res s ure
Higher
L ower
Walls
T HIC K E R : T unica
media thicker than
tunica externa
T HINNE R : T unica
extern
L umen
S maller
L arger
Valves
Valves
No valves
Valves
Valves
MOVEMENT OF BLOOD THROUGH VESSELS
 Most arterial blood is pumped by the heart
 Veins use the milking action of muscles to help move
blood
CAPILLARIES
• Microscopic--one cell layer thick
• Bathed in extracellular matrix of areolar tissue
 Capillary beds consist of two types of vessels
 Vascular shunt – directly connects an arteriole
to a venule
 True capillaries – exchange vessels
 Oxygen and nutrients cross to cells
 Carbon dioxide and metabolic waste
products cross into blood
LYMPHATIC VESSELS : ANATOMY
• Lymph- clear fluid from loose areolar CT around capillaries
• Lymphatic capillaries (near blood capillaries) 
• Lymph collecting vessels (small, 3 tunicas, valves)
• Lymph nodes (sit along collecting vessels)-clean lymph of
pathogens, they are NOT glands
• Lymphatic trunks (convergence large collecting vessels)
– Lumbar, intestinal, bronchomediastinal, subclavian,
jugular
• Lymphatic ducts  empty into veins of neck
LYMPHATIC VESSELS : FUNCTION
• Collect excess tissue fluid collecting at
arteriole end
• Return leaked blood proteins to blood
(maintain osmotic pressure needed to
take up water into bloodstream)
• Lymph moved through vessels by
– Pulse of nearby arteries
– Contraction of surrounding skeletal
muscle
– Regular movement of body (wiggling legs)
– Muscle in tunica media
• Lacteals-lymphatic capillaries w/unique
function
– In mucosa of small intestine, receive
digested fat from intestine
– Fatty lymph becomes milky = chyle
– Chyle goes to bloodstream