Blood Vessels. Types of Blood Vessels Artery – carries blood away from the heart Artery –...
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Transcript of Blood Vessels. Types of Blood Vessels Artery – carries blood away from the heart Artery –...
Blood VesselsBlood Vessels
Types of Blood VesselsTypes of Blood Vessels
Artery – carries blood away from the Artery – carries blood away from the heartheart
Vein – A vessel that carries blood Vein – A vessel that carries blood towards the hearttowards the heart
Capillaries – microscopic vessels that Capillaries – microscopic vessels that carry blood from small arteries to small carry blood from small arteries to small viens viens
The The Pathway Pathway
of of BloodBlood
ArteryArtery
ArterioleArteriole
CappillaryCappillary
VenuoleVenuole
VeinVein
Blood Vessel StructureBlood Vessel Structure
Tunica Intima (endothelium) Tunica Intima (endothelium)
Tunica Media (smooth muscle; elastic Tunica Media (smooth muscle; elastic connective tissue)connective tissue)
Tunica Adventitia (fibrous type of Tunica Adventitia (fibrous type of vessel connective tissue) vessel connective tissue)
ArteriesArteries Tunica Intima – Smooth lining Tunica Intima – Smooth lining
Tunica Media – Allows constriction and Tunica Media – Allows constriction and dilation of vessels; thicker than in dilation of vessels; thicker than in veins; muscle innervated by veins; muscle innervated by autonomic fibers autonomic fibers
Tunica Adventitia – Provides flexible Tunica Adventitia – Provides flexible support that resists collapse or injury; support that resists collapse or injury; thicker than in veins; thinner than thicker than in veins; thinner than tunica media tunica media
VeinsVeins Tunica Intima – Smooth lining with semi-Tunica Intima – Smooth lining with semi-
lunar valves to ensure one way blood flowlunar valves to ensure one way blood flow
Tunica Media – Allows constriction and Tunica Media – Allows constriction and dilation of vessels; thinner than in arteries; dilation of vessels; thinner than in arteries; muscle innervated by autonomic fibersmuscle innervated by autonomic fibers
Tunica Adventitia – Provides flexible Tunica Adventitia – Provides flexible support that resists collapse or injury; support that resists collapse or injury; thinner than in arteries; thicker than thinner than in arteries; thicker than tunica mediatunica media
CappillariesCappillaries
Tunica Intima – Makes up the entire Tunica Intima – Makes up the entire wall of the capillary; thinness permits wall of the capillary; thinness permits transport across vessel walltransport across vessel wall
Tunica Media – Absent Tunica Media – Absent
Tunica Adventitia – Absent Tunica Adventitia – Absent
Micrograph of Blood Vessel Micrograph of Blood Vessel StructureStructure
This light This light micrograph of a micrograph of a cross section of cross section of tissue contains tissue contains an artery (left) an artery (left) and a vein and a vein (right). Note the (right). Note the prominence of prominence of the smooth the smooth muscle (tunica muscle (tunica media) in the media) in the artery compared artery compared to the vein to the vein
Function of CapillariesFunction of Capillaries Most important vessels functionallyMost important vessels functionally
Very tiny (on average, only 1mm long)Very tiny (on average, only 1mm long)
According to one estimate, 1 cubic cm of According to one estimate, 1 cubic cm of muscle tissue contains more than 100,000 muscle tissue contains more than 100,000 capillariescapillaries
Primary exchange vesselsPrimary exchange vessels
The small size and large number ensures The small size and large number ensures slow blood flowslow blood flow
MicrocirculationMicrocirculation
Function of Arteries Function of Arteries
Arteries serve mainly as “distributors,” Arteries serve mainly as “distributors,” carrying blood to the arterioles, which carrying blood to the arterioles, which then carry blood to the capillariesthen carry blood to the capillaries
Arterioles are important in maintaining Arterioles are important in maintaining normal blood pressure and circulation normal blood pressure and circulation (resistance vessels)(resistance vessels)
Precapillary sphincters function as valves Precapillary sphincters function as valves regulating blood flow into the capillariesregulating blood flow into the capillaries
Function of VeinsFunction of Veins
Function both as collectors and reservoir Function both as collectors and reservoir vessels (ability to hold blood)vessels (ability to hold blood)
Capacitance -- Great ability to strech, Capacitance -- Great ability to strech, therefore, they can hold large amounts therefore, they can hold large amounts of blood with almost no change in blood of blood with almost no change in blood pressurepressure
Valves maintain the one way flow of Valves maintain the one way flow of bloodblood
The reservoir The reservoir function of function of
veinsveins
Pooled blood is Pooled blood is moved toward the moved toward the
heart as valves heart as valves are forced open are forced open by pressure from by pressure from volume of blood volume of blood
from below. from below. Closure of valves Closure of valves
prevents prevents backflow. backflow.
Circulatory RoutesCirculatory Routes
Systemic Circulation – blood is Systemic Circulation – blood is pumped from the left side of the pumped from the left side of the heart to all the tissues of the bodyheart to all the tissues of the body
Pulmonary Circulation – blood is Pulmonary Circulation – blood is pumped from the right side of the pumped from the right side of the heart to the gas exchange tissues of heart to the gas exchange tissues of the lungsthe lungs
Blood Flow Through the Blood Flow Through the Circulatory SystemCirculatory System
Main Arteries Main Arteries
of the Bodyof the Body
The AortaThe Aorta
Arteries of the Head and NeckArteries of the Head and Neck
ArteriesArteries
at the at the
Base of Base of the Brainthe Brain
Major Arteries of the Upper Major Arteries of the Upper ExtremityExtremity
Major Arteries Major Arteries
of the of the
Loser ExtremityLoser Extremity
General Principles About General Principles About VeinsVeins
Veins branch into vessels of increasing Veins branch into vessels of increasing sizesize
Vessels vary considerable in size and Vessels vary considerable in size and location from person to personlocation from person to person
Veins found deep in the body are called Veins found deep in the body are called deep veins and those found near the deep veins and those found near the surface are called superficial veinssurface are called superficial veins
Major Veins Major Veins
of theof the
BodyBody
Major Veins of the Head and Major Veins of the Head and NeckNeck
Major Major Veins of Veins of
the Upper the Upper ExtremityExtremity
Principal Veins of the ThoraxPrincipal Veins of the Thorax
Inferior Vena Cava and its Inferior Vena Cava and its Abdominopelvic TributariesAbdominopelvic Tributaries
Disorders of the Cardiovascular Disorders of the Cardiovascular SystemSystem
Mitral Valve ProlapseMitral Valve Prolapse
Coronary BypassCoronary Bypass
Partial Blockage of Artery in Partial Blockage of Artery in AtherosclerosisAtherosclerosis
Balloon AngioplastyBalloon Angioplasty
Varicose VeinsVaricose Veins