Cardiovascular System Blood Vessels. Anatomy of Blood Vessels Arteries carry blood from the heart to...
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Transcript of Cardiovascular System Blood Vessels. Anatomy of Blood Vessels Arteries carry blood from the heart to...
Cardiovascular SystemCardiovascular System
Blood VesselsBlood Vessels
Anatomy of Blood VesselsAnatomy of Blood Vessels
ArteriesArteries carry blood from the heart carry blood from the heart to the tissuesto the tissues
Anatomy of Blood VesselsAnatomy of Blood Vessels
ArteriolesArterioles are small arteries that are small arteries that connect to capillariesconnect to capillaries
Anatomy of Blood VesselsAnatomy of Blood Vessels
CapillariesCapillaries are the site of are the site of substance exchange between the substance exchange between the blood and body tissuesblood and body tissues
Anatomy of Blood VesselsAnatomy of Blood Vessels
VenulesVenules connect capillaries to connect capillaries to larger veinslarger veins
Anatomy of Blood VesselsAnatomy of Blood Vessels
VeinsVeins convey blood from the convey blood from the tissues back to the heart.tissues back to the heart.
ArteriesArteries
1.1. Tunica interna (intima) – innermostTunica interna (intima) – innermost
2.2. Tunica media – middle layerTunica media – middle layer
3.3. Tunica externa – outer layerTunica externa – outer layer
Tunica IntimaTunica Intima
Composed of;Composed of;
1.1. simple squamous epithelium simple squamous epithelium (endothelium)(endothelium)
2.2. Internal elastic membraneInternal elastic membrane
Tunica MediaTunica Media
Rich in smooth muscle and elastic Rich in smooth muscle and elastic fibersfibers
Tunica MediaTunica Media
Maintains elasticity and contractilityMaintains elasticity and contractility
Tunica ExternaTunica Externa
Rich in elastic and collagen fibersRich in elastic and collagen fibers
Functional Properties of Functional Properties of ArteriesArteries
1.1. ElasticityElasticity
2.2. ContractilityContractility
ElasticityElasticity
Due to the elastic tissue in the tunica Due to the elastic tissue in the tunica intima and mediaintima and media
ElasticityElasticity
Allows arteries to accept blood under Allows arteries to accept blood under great pressure from the contraction great pressure from the contraction of the ventricles of the ventricles
ContractilityContractility
Due to the smooth muscle in the Due to the smooth muscle in the tunica mediatunica media
ContractilityContractility
Allows arteries to increase or Allows arteries to increase or decrease lumen sizedecrease lumen size
ContractilityContractility
Sympathetic stimulation of alpha 1 Sympathetic stimulation of alpha 1 receptors on cutaneous arteries receptors on cutaneous arteries causes vasoconstrictioncauses vasoconstriction
ContractilityContractility
Sympathetic stimulation of beta 2 Sympathetic stimulation of beta 2 receptors on arteries supplying receptors on arteries supplying skeletal muscle causes vasodilationskeletal muscle causes vasodilation
Elastic ArteriesElastic Arteries
Elastic Arteries – Large arteries with Elastic Arteries – Large arteries with more elastic fibers and less smooth more elastic fibers and less smooth musclemuscle
Elastic ArteriesElastic Arteries
Example: aorta, sublcavian, and Example: aorta, sublcavian, and pulmonary arteriespulmonary arteries
Elastic ArteriesElastic Arteries
Also called Also called conducting arteriesconducting arteries because they conduct blood from the because they conduct blood from the heart to medium sized arteriesheart to medium sized arteries
Muscular or distributing Muscular or distributing arteriesarteries
Medium sized and have a large Medium sized and have a large amount of smooth muscle and amount of smooth muscle and distribute blood to various parts of distribute blood to various parts of the bodythe body
Muscular or distributing Muscular or distributing arteriesarteries
Examples: brachial, femoral, and Examples: brachial, femoral, and popliteal arteriespopliteal arteries
ArteriolesArterioles
Very small arteries that deliver blood Very small arteries that deliver blood to capillariesto capillaries
CapillariesCapillaries
Connect arterioles and venulesConnect arterioles and venules
CapillariesCapillaries
Microcirculation – flow of blood Microcirculation – flow of blood through the capillariesthrough the capillaries
CapillariesCapillaries
Capillaries are found near almost Capillaries are found near almost every cell in the bodyevery cell in the body
CapillariesCapillaries
Function – Permit the exchange of Function – Permit the exchange of nutrients and wastes between the nutrients and wastes between the blood and tissue cellsblood and tissue cells
CapillariesCapillaries
Composed of a single layer of cells Composed of a single layer of cells (endothelium) and a basement (endothelium) and a basement membranemembrane
CapillariesCapillaries
Two types;Two types;
1.1. Continuous Continuous
2.2. Fenestrated Fenestrated
CapillariesCapillaries
Continuous – Continuous – composed of composed of endothelial cells endothelial cells that form a that form a continuous tube continuous tube that contains gaps that contains gaps between cells between cells called called intercellular intercellular cleftsclefts
CapillariesCapillaries
Fenestrated Fenestrated capillaries – plasma capillaries – plasma membrane membrane contains small contains small porespores
CapillariesCapillaries
Materials can cross the blood Materials can cross the blood capillary walls in four wayscapillary walls in four ways
CapillariesCapillaries
Four Ways;Four Ways;
1.1. Intercellular cleftsIntercellular clefts
2.2. Trancytosis using pinocytic vesiclesTrancytosis using pinocytic vesicles
3.3. DiffusionDiffusion
4.4. Fenestrations Fenestrations
Intercellular cleftsIntercellular clefts
Open in response to histamine Open in response to histamine (released during inflamation) making (released during inflamation) making capillaries more leakycapillaries more leaky
Intercellular cleftsIntercellular clefts
This allows fluid and wbc, and This allows fluid and wbc, and antibodies to go from the antibodies to go from the bloodstream to the site of infectionbloodstream to the site of infection
PinocytosisPinocytosis
Large fats cross via pinocytosisLarge fats cross via pinocytosis
DiffusionDiffusion
Water, CO2, and O2 cross capillaries Water, CO2, and O2 cross capillaries by diffusionby diffusion
FenestrationsFenestrations
Allow small molecules such as water Allow small molecules such as water and electrolytes to get into the urineand electrolytes to get into the urine
FenestrationsFenestrations
Prevent large proteins and red cells Prevent large proteins and red cells from getting into the urinefrom getting into the urine
SinusoidsSinusoids
Discontinuous Discontinuous capillariescapillaries
SinusoidsSinusoids
Present in the liverPresent in the liver
SinusoidsSinusoids
Allow large molecules such as protein Allow large molecules such as protein and bilirubin to get from the and bilirubin to get from the bloodstream into hepatocytesbloodstream into hepatocytes
VenulesVenules
They are small vessels that are They are small vessels that are formed from the union of several formed from the union of several capillariescapillaries
VenulesVenules
Merges to form veinsMerges to form veins
VenulesVenules
Drain blood from capillaries into Drain blood from capillaries into veinsveins
VeinsVeins
Contain 60% of our blood volumeContain 60% of our blood volume
VeinsVeins
Consist of the same three tunics as Consist of the same three tunics as arteriesarteries
VeinsVeins
Have a thinner tunica intima and Have a thinner tunica intima and mediamedia
VeinsVeins
Thicker tunica externaThicker tunica externa
VeinsVeins
Thinner walled than arteries due to Thinner walled than arteries due to less elastic tissue and smooth muscleless elastic tissue and smooth muscle
VeinsVeins
Low pressure systemsLow pressure systems
VeinsVeins
Contain valves to prevent backflowContain valves to prevent backflow
VeinsVeins
Squeezing of the veins by muscles Squeezing of the veins by muscles and inspiration promote venous and inspiration promote venous returnreturn
Venous ReturnVenous Return
The volume of blood returning back The volume of blood returning back to the heart from the systemic veinsto the heart from the systemic veins
VeinsVeins
Vascular sinuses – veins with very Vascular sinuses – veins with very thin walls with no smooth muscle to thin walls with no smooth muscle to alter their diameteralter their diameter
Example: Coronary sinusExample: Coronary sinus
AnastomosesAnastomoses
Union of the branches of two or more Union of the branches of two or more arteries supplying the same regionarteries supplying the same region
AnastomosesAnastomoses
Provide alternate routes for blood to Provide alternate routes for blood to reach a tissue or organreach a tissue or organ
AnastomosesAnastomoses
Collateral circulation is the alternate Collateral circulation is the alternate flow of blood to a body part through flow of blood to a body part through an anastomosisan anastomosis
AnastomosesAnastomoses
What is the importance of arteries What is the importance of arteries that anastomose?that anastomose?
AnastomosesAnastomoses
Occlusion of an end artery interrupts Occlusion of an end artery interrupts the blood supply to a whole segment the blood supply to a whole segment of an organ, producing necrosis of of an organ, producing necrosis of that segmentthat segment
Blood PressureBlood Pressure
Pressure exerted on the walls of a Pressure exerted on the walls of a blood vesselblood vessel
Blood PressureBlood Pressure
In a clinical sense, it refers to In a clinical sense, it refers to pressure in arteriespressure in arteries
Blood PressureBlood Pressure
BP=CO X TPRBP=CO X TPR
Blood PressureBlood Pressure
Systolic and Diastolic fluctuations in Systolic and Diastolic fluctuations in the pressure are only seen in the the pressure are only seen in the arteries and arteriolesarteries and arterioles
Systolic PressureSystolic Pressure
Peak pressure in the arteries with Peak pressure in the arteries with each cardiac cycle during ventricular each cardiac cycle during ventricular contractioncontraction
Systolic PressureSystolic Pressure
Due to the stroke volume being Due to the stroke volume being ejected into the aortaejected into the aorta
Diastolic PressureDiastolic Pressure
Lowest pressure in the arteries with Lowest pressure in the arteries with each cardiac cycleeach cardiac cycle
Diastolic PressureDiastolic Pressure
Force of blood recorded during Force of blood recorded during ventricular relaxationventricular relaxation
Blood PressureBlood Pressure
Young adult male = 120/80 mm Hg Young adult male = 120/80 mm Hg (8-10 mm Hg less in a young adult (8-10 mm Hg less in a young adult female)female)
ResistanceResistance
Depends on three variables;Depends on three variables;
1.1. Blood viscosityBlood viscosity
2.2. Vessel lengthVessel length
3.3. Blood Vessel RadiusBlood Vessel Radius
Blood ViscosityBlood Viscosity
Increased viscosity increases Increased viscosity increases resistanceresistance
Vessel lengthVessel length
Increased length increases resistanceIncreased length increases resistance
Blood Vessel RadiusBlood Vessel Radius
Increased radius decreases Increased radius decreases resistanceresistance
Systemic vascular resistanceSystemic vascular resistance
Total peripheral resistance (TPR)Total peripheral resistance (TPR)
Systemic vascular resistanceSystemic vascular resistance
All of the vascular resistance offered All of the vascular resistance offered by systemic blood vesselsby systemic blood vessels
Mean Arterial PressureMean Arterial Pressure
MAP = Diastolic Pressure X MAP = Diastolic Pressure X 1/3(systolic pressure – diastolic 1/3(systolic pressure – diastolic pressure)pressure)
Mean Arterial PressureMean Arterial Pressure
MAP = CO X TPRMAP = CO X TPR
Mean Arterial PressureMean Arterial Pressure
Factors that increase BPFactors that increase BP increase SVincrease SV increase HRincrease HR constrict the blood vessels constrict the blood vessels
(increases resistance)(increases resistance)
Mean Arterial PressureMean Arterial Pressure
Factors that decrease BPFactors that decrease BP Decrease CODecrease CO Dilate the arteriesDilate the arteries
Cardiovascular CenterCardiovascular Center
A group of neurons in the medulla A group of neurons in the medulla that regulate heart rate, contractility, that regulate heart rate, contractility, and blood vessel diameterand blood vessel diameter
Cardiovascular CenterCardiovascular Center
CV receives input from higher brain CV receives input from higher brain regions and sensory receptors regions and sensory receptors (baroreceptors and chemoreceptors)(baroreceptors and chemoreceptors)
Cardiovascular CenterCardiovascular Center
Sympathetic impulses along Sympathetic impulses along cardioaccelerator nerves increase cardioaccelerator nerves increase heart rate and contractilityheart rate and contractility
Cardiovascular CenterCardiovascular Center
Parasympathetic impulse along Parasympathetic impulse along vagus nerves decrease heart ratevagus nerves decrease heart rate
Cardiovascular CenterCardiovascular Center
The sympathetic division also The sympathetic division also continually sends impulses to smooth continually sends impulses to smooth muscle in blood vessel walls via muscle in blood vessel walls via vasomoter nerves resulting in a vasomoter nerves resulting in a moderate state of tonic moderate state of tonic vasoconstrictionvasoconstriction
Neural Regulation of Blood Neural Regulation of Blood PressurePressure
BaroreceptorsBaroreceptorsChemoreceptorsChemoreceptors
BaroreceptorsBaroreceptors
Pressure-sensitive sensory neurons Pressure-sensitive sensory neurons that monitor stretching of the walls that monitor stretching of the walls of blood vesselsof blood vessels
BaroreceptorsBaroreceptors
If blood pressure falls, the If blood pressure falls, the baroreceptor reflexes;baroreceptor reflexes;
accelerate heart rateaccelerate heart rate increase force of contractionincrease force of contraction promote vasoconstrictionpromote vasoconstriction
BaroreceptorsBaroreceptors
If pressure increases above normal, If pressure increases above normal, the reflexes cause;the reflexes cause;
decrease in sympathetic tonedecrease in sympathetic tone increase in parasympathetic toneincrease in parasympathetic tone
Hormonal RegulationHormonal Regulation
Renin leads to the formation of Renin leads to the formation of angiotensin IIangiotensin II
Hormonal RegulationHormonal Regulation
Angiotensin II causes;Angiotensin II causes;
1.1. VasoconstrictionVasoconstriction
2.2. Secretion of aldosterone, which Secretion of aldosterone, which leads to sodium and water retentionleads to sodium and water retention
Hormonal RegulationHormonal Regulation
Epinephrine and norepinephrine Epinephrine and norepinephrine increase CO and cause increase CO and cause vasoconstrictionvasoconstriction
Hormonal RegulationHormonal Regulation
ADH causes water retention and a ADH causes water retention and a little vasoconstrictionlittle vasoconstriction
Hormonal RegulationHormonal Regulation
Nitric oxide from the endothelial cells Nitric oxide from the endothelial cells causes vasodilationcauses vasodilation
Hormonal RegulationHormonal Regulation
Cortisol keep our arteries sensitive to Cortisol keep our arteries sensitive to vasoconstricting hormonesvasoconstricting hormones
ShockShock
Is an inadequate CO that results in Is an inadequate CO that results in failure of the CV system to deliver failure of the CV system to deliver adequate amounts of O2 and adequate amounts of O2 and nutrients to meet the metabolic nutrients to meet the metabolic needs of body cellsneeds of body cells
ShockShock
Could result in;Could result in; dysfunction of cellular membranesdysfunction of cellular membranes abnormal cellular metabolismabnormal cellular metabolism cellular deathcellular death
Types of ShockTypes of Shock
5 main types5 main types
Hypovolemic ShockHypovolemic Shock
Due to decreased blood volumeDue to decreased blood volume
Cardiogenic ShockCardiogenic Shock
Due to poor heart functionDue to poor heart function
Vascular ShockVascular Shock
Due to inappropriate vasodilationDue to inappropriate vasodilation
Obstructive ShockObstructive Shock
Due to obstruction of blood flowDue to obstruction of blood flow
Neurogenic shockNeurogenic shock
Due to decreased sympathetic Due to decreased sympathetic outflowoutflow
Homeostatic ResponseHomeostatic Response
Activation of renin-angiotensin-Activation of renin-angiotensin-aldosterone systemaldosterone system
Homeostatic ResponseHomeostatic Response
Secretion of ADHSecretion of ADH
Homeostatic ResponseHomeostatic Response
Activation of the sympathetic division Activation of the sympathetic division of the ANSof the ANS
Circulatory RoutesCirculatory Routes
SystemicSystemicPulmonaryPulmonaryHepatic PortalHepatic PortalFetalFetal
Hepatic Portal CirculationHepatic Portal Circulation
Collects blood from the veins of the Collects blood from the veins of the pancreas, spleen, stomach, pancreas, spleen, stomach, intestines and gallbladder and directs intestines and gallbladder and directs it into the hepatic portal vein of the it into the hepatic portal vein of the liver before it returns to the heartliver before it returns to the heart
Hepatic Portal CirculationHepatic Portal Circulation
Enables nutrient utilization and blood Enables nutrient utilization and blood detoxification by the liverdetoxification by the liver