the circulatory system “pump it”. the cardiovascular system a closed system of the heart and...

The Circulatory The Circulatory SystemSystem

““PUMP IT”PUMP IT”

The Cardiovascular SystemThe Cardiovascular System

A closed system of the heart and A closed system of the heart and blood vesselsblood vessels– The heart pumps bloodThe heart pumps blood– Blood vessels allow blood to circulate to Blood vessels allow blood to circulate to

all parts of the bodyall parts of the body The function of the cardiovascular The function of the cardiovascular

system is to deliver oxygen and system is to deliver oxygen and nutrients and to remove carbon nutrients and to remove carbon dioxide and other waste productsdioxide and other waste products

What is it?What is it?

Size and Location of the Size and Location of the HeartHeart

Vary with body sizeVary with body size Average 14cm long, 9cm wideAverage 14cm long, 9cm wide Located within the mediastinumLocated within the mediastinum

– Bordered:Bordered: Laterally by lungsLaterally by lungs Posteriorly by vertebral columnPosteriorly by vertebral column Anteriorly by sternumAnteriorly by sternum Base lies beneath 2Base lies beneath 2ndnd rib rib Distal end extends downward and to the leftDistal end extends downward and to the left Terminates as a bluntly pointed apex at 5Terminates as a bluntly pointed apex at 5thth

intercostal spaceintercostal space

The HeartThe Heart

Figure 11.1a–b

The HeartThe Heart

Figure 11.1c

Cardiovascular SystemCardiovascular System

Structures include:Structures include:– heartheart– Blood vesselsBlood vessels

Functions:Functions:– Bring oxygen and nutrients to all body Bring oxygen and nutrients to all body

cellscells– Remove wastesRemove wastes

General structure of the HeartGeneral structure of the Heart

Hollow, cone-shaped, muscular pumpHollow, cone-shaped, muscular pump Located in the thoracic cavityLocated in the thoracic cavity Rests on the diaphragmRests on the diaphragm

The HeartThe Heart

Figure 11.2a

The Heart: CoveringsThe Heart: Coverings Pericardium—a double-walled sacPericardium—a double-walled sac

– Fibrous pericardium is loose and Fibrous pericardium is loose and superficialsuperficial

– Serous membrane is deep to the fibrous Serous membrane is deep to the fibrous pericardium and composed of two layerspericardium and composed of two layers Visceral pericardiumVisceral pericardium

– Next to heart; also known as the epicardiumNext to heart; also known as the epicardium Parietal pericardium Parietal pericardium

– Outside layer that lines the inner surface of the Outside layer that lines the inner surface of the fibrous pericardiumfibrous pericardium

– Serous fluid fills the space between the Serous fluid fills the space between the layers of pericardiumlayers of pericardium

The Heart: Heart WallThe Heart: Heart Wall

Figure 11.2b

The Heart: Heart WallThe Heart: Heart Wall Three layersThree layers

– EpicardiumEpicardium Outside layerOutside layer This layer is the visceral pericardiumThis layer is the visceral pericardium Connective tissue layerConnective tissue layer

– MyocardiumMyocardium Middle layerMiddle layer Mostly cardiac muscleMostly cardiac muscle

– EndocardiumEndocardium Inner layerInner layer EndotheliumEndothelium


Figure 11.2b


Figure 11.2c

The Heart: ChambersThe Heart: Chambers

Right and left side act as separate Right and left side act as separate pumpspumps

Four chambersFour chambers– AtriaAtria

Receiving chambersReceiving chambers– Right atriumRight atrium– Left atriumLeft atrium

– VentriclesVentricles Discharging chambersDischarging chambers

– Right ventricleRight ventricle– Left ventricleLeft ventricle


Figure 11.2c

Differences in Right and Left Differences in Right and Left VentriclesVentricles

Figure 11.4

The Heart: Septa The Heart: Septa

Interventricular septum Interventricular septum – Separates the two ventriclesSeparates the two ventricles

Interatrial septum Interatrial septum – Separates the two atriaSeparates the two atria


Figure 11.2c

The Heart: ValvesThe Heart: Valves

Allow blood to flow in only one Allow blood to flow in only one direction to prevent backflowdirection to prevent backflow

Four valvesFour valves– Atrioventricular (AV) valves—between Atrioventricular (AV) valves—between

atria and ventriclesatria and ventricles Bicuspid (mitral) valve (left side of heart)Bicuspid (mitral) valve (left side of heart) Tricuspid valve (right side of heart) Tricuspid valve (right side of heart)

– Semilunar valves—between ventricle and Semilunar valves—between ventricle and arteryartery Pulmonary semilunar valvePulmonary semilunar valve Aortic semilunar valveAortic semilunar valve

The Heart: ValvesThe Heart: Valves

Figure 11.2c

The Heart: ValvesThe Heart: Valves AV valves AV valves

– Anchored in place by chordae tendineae (“heart Anchored in place by chordae tendineae (“heart strings”)strings”)

– OpenOpen during heart relaxation and during heart relaxation and closedclosed during during ventricular contractionventricular contraction

Semilunar valvesSemilunar valves– ClosedClosed during heart relaxation but during heart relaxation but openopen during during

ventricular contractionventricular contraction Notice these valves operate opposite of one Notice these valves operate opposite of one

another to force a one-way path of blood another to force a one-way path of blood through the heartthrough the heart

Figure 11.5a, step 1

Blood returning tothe atria, putspressure againstAV valves; the AVvalves are forcedopen

Ventricles

Operation of the AV valves

AV valves open

(a)



As the ventriclesfill, AV valve flapshang limply intoventricles

Ventricles


AV valves open

(a)



As the ventriclesfill, AV valve flapshang limply intoventricles

Atria contract,forcing additionalblood into ventricles

Ventricles


AV valves open

(a)


Ventricles contract,forcing bloodagainst AV valveflaps

(a)



AV valves close

AV valves closed(a)



AV valves close

Chordae tendineaetighten, preventingvalve flaps fromeverting into atria

AV valves closed(a)

Oxygen-poor blood (shown in Oxygen-poor blood (shown in blue) flows from the body into the blue) flows from the body into the right atrium.right atrium.

Blood flows through the right Blood flows through the right atrium into the right ventricle.atrium into the right ventricle.

The right ventricle pumps the The right ventricle pumps the blood to the lungs, where the blood to the lungs, where the blood releases waste gases and blood releases waste gases and picks up oxygen.picks up oxygen.

The newly oxygen-rich blood The newly oxygen-rich blood (shown in red) returns to the (shown in red) returns to the heart and enters the left atrium.heart and enters the left atrium.

Blood flows through the left Blood flows through the left atrium into the left ventricle.atrium into the left ventricle.

The left ventricle pumps the The left ventricle pumps the oxygen-rich blood to all parts of oxygen-rich blood to all parts of the bodythe body

Figure 11.5b, step 1

As ventriclescontract andintraventricularpressure rises,blood is pushedup againstsemilunarvalves, forcingthem open

Aorta

Pulmonarytrunk

Semilunar valveopen

Operation of the semilunar valves

(b)

Figure 11.5b, step 2

As ventriclescontract andintraventricularpressure rises,blood is pushedup againstsemilunarvalves, forcingthem open

Aorta

Pulmonarytrunk

Semilunar valveopen Semilunar valve

closed

As ventriclesrelax, andintraventricularpressure falls,blood flowsback fromarteries, fillingthe leaflets of semilunarvalves andforcing themto close

Operation of the semilunar valves

(b)

Systemic and Pulmonary Systemic and Pulmonary CirculationsCirculations

Systemic circulationSystemic circulation– Blood flows from the left side of the Blood flows from the left side of the

heart through the body tissues and back heart through the body tissues and back to the right side of the heartto the right side of the heart

Pulmonary circulationPulmonary circulation– Blood flows from the right side of the Blood flows from the right side of the

heart to the lungs and back to the left heart to the lungs and back to the left side of the heartside of the heart


Figure 11.3

The Heart: Associated Great The Heart: Associated Great VesselsVessels

ArteriesArteries– AortaAorta

Leaves left ventricleLeaves left ventricle

– Pulmonary arteriesPulmonary arteries Leave right ventricleLeave right ventricle


VeinsVeins– Superior and inferior venae cavaeSuperior and inferior venae cavae

Enter right atriumEnter right atrium

– Pulmonary veins (four)Pulmonary veins (four) Enter left atriumEnter left atrium


Figure 11.2c

Blood Flow Through the Blood Flow Through the HeartHeart

Superior and inferior venae cavae dump Superior and inferior venae cavae dump blood into the right atriumblood into the right atrium

From right atrium, through the tricuspid From right atrium, through the tricuspid valve, blood travels to the right ventriclevalve, blood travels to the right ventricle

From the right ventricle, blood leaves the From the right ventricle, blood leaves the heart as it passes through the pulmonary heart as it passes through the pulmonary semilunar valve into the pulmonary trunksemilunar valve into the pulmonary trunk

Pulmonary trunk splits into right and left Pulmonary trunk splits into right and left pulmonary arteries that carry blood to the pulmonary arteries that carry blood to the lungslungs

Blood Flow Through the Blood Flow Through the HeartHeart

Oxygen is picked up and carbon dioxide is Oxygen is picked up and carbon dioxide is dropped off by blood in the lungsdropped off by blood in the lungs

Oxygen-rich blood returns to the heart Oxygen-rich blood returns to the heart through the four pulmonary veinsthrough the four pulmonary veins

Blood enters the left atrium and travels Blood enters the left atrium and travels through the bicuspid valve into the left through the bicuspid valve into the left ventricleventricle

From the left ventricle, blood leaves the From the left ventricle, blood leaves the heart via the aortic semilunar valve and heart via the aortic semilunar valve and aortaaorta


Figure 11.3

Heart ContractionsHeart Contractions

Figure 11.6


Contraction is initiated by the Contraction is initiated by the sinoatrial node (SA node)sinoatrial node (SA node)

Sequential stimulation occurs at Sequential stimulation occurs at other autorhythmic cellsother autorhythmic cells

Force cardiac muscle depolarization Force cardiac muscle depolarization in one direction—from atria to in one direction—from atria to ventriclesventricles


Once SA node starts the heartbeatOnce SA node starts the heartbeat– Impulse spreads to the AV node Impulse spreads to the AV node – Then the atria contractThen the atria contract

At the AV node, the impulse passes At the AV node, the impulse passes through the AV bundle, bundle through the AV bundle, bundle branches, and Purkinje fibersbranches, and Purkinje fibers

Blood is ejected from the ventricles to Blood is ejected from the ventricles to the aorta and pulmonary trunk as the the aorta and pulmonary trunk as the ventricles contractventricles contract


Figure 11.6


Tachycardia—rapid heart rate over Tachycardia—rapid heart rate over 100 beats per minute100 beats per minute

Bradycardia—slow heart rate less Bradycardia—slow heart rate less than 60 beats per minutesthan 60 beats per minutes

The Heart: Cardiac CycleThe Heart: Cardiac Cycle

Atria contract simultaneouslyAtria contract simultaneously Atria relax, then ventricles contractAtria relax, then ventricles contract Systole = contractionSystole = contraction Diastole = relaxationDiastole = relaxation

Filling Heart Chambers: Cardiac Filling Heart Chambers: Cardiac CycleCycle

Figure 11.7

Atrialcontraction

Mid-to-late diastole(ventricular filling)

Ventricular systole(atria in diastole)

Early diastole

Isovolumetriccontraction phase

Ventricularejection phase

Isovolumetricrelaxation

Ventricularfilling

Left atriumRight atrium

Left ventricleRight ventricle


Figure 11.7, step 1a


Ventricularfilling




Figure 11.7, step 1b

Atrialcontraction


Ventricularfilling




Figure 11.7, step 2a

Atrialcontraction




Ventricularfilling




Figure 11.7, step 2b

Atrialcontraction





Ventricularfilling




Figure 11.7, step 3

Atrialcontraction



Early diastole



Isovolumetricrelaxation

Ventricularfilling



The Heart: Cardiac CycleThe Heart: Cardiac Cycle

Cardiac cycle—events of one Cardiac cycle—events of one complete heart beatcomplete heart beat– Mid-to-late diastole—blood flows from Mid-to-late diastole—blood flows from

atria into ventriclesatria into ventricles– Ventricular systole—blood pressure Ventricular systole—blood pressure

builds before ventricle contracts, builds before ventricle contracts, pushing out bloodpushing out blood

– Early diastole—atria finish refilling, Early diastole—atria finish refilling, ventricular pressure is lowventricular pressure is low

The Heart: Cardiac OutputThe Heart: Cardiac Output

Cardiac output (CO)Cardiac output (CO)– Amount of blood pumped by each side Amount of blood pumped by each side

(ventricle) of the heart in one minute(ventricle) of the heart in one minute Stroke volume (SV)Stroke volume (SV)

– Volume of blood pumped by each ventricle in Volume of blood pumped by each ventricle in one contraction (each heartbeat)one contraction (each heartbeat)

– Usually remains relatively constant Usually remains relatively constant – About 70 mL of blood is pumped out of the About 70 mL of blood is pumped out of the

left ventricle with each heartbeatleft ventricle with each heartbeat Heart rate (HR) Heart rate (HR)

– Typically 75 beats per minuteTypically 75 beats per minute

The Heart: Cardiac OutputThe Heart: Cardiac Output

CO = HR CO = HR SV SV CO = HR (75 beats/min) CO = HR (75 beats/min) SV (70 SV (70

mL/beat)mL/beat) CO = 5250 mL/minCO = 5250 mL/min Starling’s law of the heart—the more the Starling’s law of the heart—the more the

cardiac muscle is stretched, the stronger cardiac muscle is stretched, the stronger the contractionthe contraction

Changing heart rate is the most common Changing heart rate is the most common way to change cardiac outputway to change cardiac output

The Heart: Regulation of The Heart: Regulation of Heart RateHeart Rate

Increased heart rateIncreased heart rate– Sympathetic nervous systemSympathetic nervous system

CrisisCrisis Low blood pressureLow blood pressure

– HormonesHormones EpinephrineEpinephrine ThyroxineThyroxine

– ExerciseExercise– Decreased blood volumeDecreased blood volume

The Heart: Regulation of The Heart: Regulation of Heart RateHeart Rate

Decreased heart rateDecreased heart rate– Parasympathetic nervous systemParasympathetic nervous system– High blood pressure or blood volumeHigh blood pressure or blood volume– Decreased venous returnDecreased venous return

Cardiac Output RegulationCardiac Output Regulation

Figure 11.8

Blood Vessels: The Vascular Blood Vessels: The Vascular SystemSystem

Transport blood to the tissues and Transport blood to the tissues and backback– Carry blood away from the heartCarry blood away from the heart

ArteriesArteries ArteriolesArterioles

– Exchanges between tissues and bloodExchanges between tissues and blood Capillary bedsCapillary beds

– Return blood toward the heartReturn blood toward the heart VenulesVenules VeinsVeins


Figure 11.9a

Blood Vessels: Microscopic Blood Vessels: Microscopic AnatomyAnatomy Three layers (tunics)Three layers (tunics)

– Tunic intimaTunic intima EndotheliumEndothelium

– Tunic mediaTunic media Smooth muscleSmooth muscle Controlled by sympathetic nervous Controlled by sympathetic nervous

systemsystem

– Tunic externaTunic externa Mostly fibrous connective tissueMostly fibrous connective tissue


Figure 11.9b

Differences Between Blood Differences Between Blood VesselsVessels

Walls of arteries are the thickestWalls of arteries are the thickest Lumens of veins are largerLumens of veins are larger Larger veins have valves to prevent Larger veins have valves to prevent

backflowbackflow Skeletal muscle “milks” blood in veins Skeletal muscle “milks” blood in veins

toward the hearttoward the heart Walls of capillaries are only one cell Walls of capillaries are only one cell

layer thick to allow for exchanges layer thick to allow for exchanges between blood and tissuebetween blood and tissue


Figure 11.9a


Figure 11.10

Movement of Blood Through Movement of Blood Through VesselsVessels

Most arterial blood is pumped by the Most arterial blood is pumped by the heartheart

Veins use the milking action of Veins use the milking action of muscles to help move bloodmuscles to help move blood

Capillary BedsCapillary Beds

Capillary beds consist of two types of Capillary beds consist of two types of vesselsvessels– Vascular shunt—vessel directly Vascular shunt—vessel directly

connecting an arteriole to a venuleconnecting an arteriole to a venule– True capillaries—exchange vesselsTrue capillaries—exchange vessels

Oxygen and nutrients cross to cellsOxygen and nutrients cross to cells Carbon dioxide and metabolic waste Carbon dioxide and metabolic waste

products cross into bloodproducts cross into blood


Figure 11.11a


Figure 11.11b

Major Arteries of System Major Arteries of System CirculationCirculation

AortaAorta– Largest artery in the bodyLargest artery in the body– Leaves from the left ventricle of the heartLeaves from the left ventricle of the heart– RegionsRegions

Ascending aorta—leaves the left ventricleAscending aorta—leaves the left ventricle Aortic arch—arches to the leftAortic arch—arches to the left Thoracic aorta—travels downward through the Thoracic aorta—travels downward through the

thoraxthorax Abdominal aorta—passes through the Abdominal aorta—passes through the

diaphragm into the abdominopelvic cavitydiaphragm into the abdominopelvic cavity

Major Arteries of System Major Arteries of System CirculationCirculation

Arterial branches of the ascending Arterial branches of the ascending aortaaorta– Right and left coronary arteries serve Right and left coronary arteries serve

the heartthe heart

The HeartThe Heart

Figure 11.2a

Major Arteries of Systemic Major Arteries of Systemic CirculationCirculation

Arterial branches of the aortia arch (BCS)Arterial branches of the aortia arch (BCS)– Brachiocephalic trunk splits into theBrachiocephalic trunk splits into the

Right common carotid arteryRight common carotid artery Right subclavian arteryRight subclavian artery

– Left common carotid artery splits into theLeft common carotid artery splits into the Left internal and external carotid arteries Left internal and external carotid arteries

– Left subclavian artery branches into theLeft subclavian artery branches into the Vertebral arteryVertebral artery In the axilla, the subclavian artery becomes the In the axilla, the subclavian artery becomes the

axillary artery axillary artery brachial artery brachial artery radial and radial and ulnar arteriesulnar arteries


Arterial branches of the thoracic Arterial branches of the thoracic aortaaorta– Intercostal arteries supply the muscles Intercostal arteries supply the muscles

of the thorax wallof the thorax wall– Other branches of the thoracic aorta Other branches of the thoracic aorta

supply thesupply the Lungs (bronchial arteries)Lungs (bronchial arteries) Esophagus (esophageal arteries)Esophagus (esophageal arteries) Diaphragm (phrenic arteries)Diaphragm (phrenic arteries)


Arterial branches of the abdominal Arterial branches of the abdominal aortaaorta– Celiac trunk is the first branch of the Celiac trunk is the first branch of the

abdominal aorta. Three branches areabdominal aorta. Three branches are Left gastric artery (stomach)Left gastric artery (stomach) Splenic artery (spleen)Splenic artery (spleen) Common hepatic artery (liver)Common hepatic artery (liver)

– Superior mesenteric artery supplies most Superior mesenteric artery supplies most of the small intestine and first half of the of the small intestine and first half of the large intestinelarge intestine


Arterial branches of the abdominal Arterial branches of the abdominal aortaaorta– Left and right renal arteries (kidney)Left and right renal arteries (kidney)– Left and right gonadal arteries Left and right gonadal arteries

Ovarian arteries in females serve the ovariesOvarian arteries in females serve the ovaries Testicular arteries in males serve the testesTesticular arteries in males serve the testes

– Lumbar arteries serve muscles of the Lumbar arteries serve muscles of the abdomen and trunkabdomen and trunk


Arterial branches of the abdominal Arterial branches of the abdominal aortaaorta– Inferior mesenteric artery serves the Inferior mesenteric artery serves the

second half of the large intestinesecond half of the large intestine– Left and right common iliac arteries are Left and right common iliac arteries are

the final branches of the aortathe final branches of the aorta Internal iliac arteries serve the pelvic organsInternal iliac arteries serve the pelvic organs External iliac arteries enter the thigh External iliac arteries enter the thigh

femoral artery femoral artery popliteal artery popliteal artery anterior anterior and posterior tibial arteriesand posterior tibial arteries


Figure 11.12

Major Veins of Systemic Major Veins of Systemic CirculationCirculation

Superior and inferior vena cava enter Superior and inferior vena cava enter the right atrium of the heartthe right atrium of the heart– Superior vena cava drains the head and Superior vena cava drains the head and

armsarms– Inferior vena cava drains the lower bodyInferior vena cava drains the lower body

The HeartThe Heart

Figure 11.2b


Veins draining into the superior vena Veins draining into the superior vena cavacava– Radial and ulnar veins Radial and ulnar veins brachial vein brachial vein

axillary vein axillary vein – These veins drain the armsThese veins drain the arms– Cephalic vein drains the lateral aspect of Cephalic vein drains the lateral aspect of

the arm and empties into the axillary veinthe arm and empties into the axillary vein– Basilic vein drains the medial aspect of the Basilic vein drains the medial aspect of the

arm and empties into the brachial veinarm and empties into the brachial vein– Basilic and cephalic veins are jointed at Basilic and cephalic veins are jointed at

the median cubital vein (elbow area)the median cubital vein (elbow area)


Veins draining into the superior vena Veins draining into the superior vena cavacava– Subclavian vein receivesSubclavian vein receives

Venous blood from the arm via the axillary veinVenous blood from the arm via the axillary vein Venous blood from skin and muscles via Venous blood from skin and muscles via

external jugular veinexternal jugular vein

– Vertebral vein drains the posterior part of Vertebral vein drains the posterior part of the headthe head

– Internal jugular vein drains the dural Internal jugular vein drains the dural sinuses of the brainsinuses of the brain


Veins draining into the superior vena Veins draining into the superior vena cavacava– Left and right brachiocephalic veins receive Left and right brachiocephalic veins receive

venous blood from thevenous blood from the Subclavian veinsSubclavian veins Vertebral veinsVertebral veins Internal jugular veinsInternal jugular veins

– Brachiocephalic veins join to form the Brachiocephalic veins join to form the superior vena cava superior vena cava right atrium of heart right atrium of heart

– Azygous vein drains the thoraxAzygous vein drains the thorax


Veins draining into the inferior vena cavaVeins draining into the inferior vena cava– Anterior and posterior tibial veins and fibial Anterior and posterior tibial veins and fibial

veins drain the legsveins drain the legs– Posterior tibial vein Posterior tibial vein popliteal vein popliteal vein

femoral vein femoral vein external iliac vein external iliac vein– Great saphenous veins (longest veins of the Great saphenous veins (longest veins of the

body) receive superficial drainage of the legsbody) receive superficial drainage of the legs– Each common iliac vein (left and right) is Each common iliac vein (left and right) is

formed by the union of the internal and formed by the union of the internal and external iliac vein on its own sideexternal iliac vein on its own side


Veins draining into the inferior vena cavaVeins draining into the inferior vena cava– Right gonadal vein drains the right ovary in Right gonadal vein drains the right ovary in

females and right testicle in malesfemales and right testicle in males– Left gonadal vein empties into the left renal Left gonadal vein empties into the left renal

veinvein– Left and right renal veins drain the kidneysLeft and right renal veins drain the kidneys– Hepatic portal vein drains the digestive Hepatic portal vein drains the digestive

organs and travels through the liver before it organs and travels through the liver before it enters systemic circulationenters systemic circulation


Veins draining into the inferior vena Veins draining into the inferior vena cavacava– Left and right hepatic veins drain the Left and right hepatic veins drain the

liverliver


Figure 11.13

Arterial Supply of the BrainArterial Supply of the Brain

Internal carotid arteries divide intoInternal carotid arteries divide into– Anterior and middle cerebral arteriesAnterior and middle cerebral arteries– These arteries supply most of the These arteries supply most of the

cerebrumcerebrum Vertebral arteries join once within Vertebral arteries join once within

the skull to form the basilar arterythe skull to form the basilar artery– Basilar artery serves the brain stem Basilar artery serves the brain stem

and cerebellumand cerebellum


Posterior cerebral arteries form from Posterior cerebral arteries form from the division of the basilar arterythe division of the basilar artery– These arteries supply the posterior These arteries supply the posterior

cerebrumcerebrum

Circle of WillisCircle of Willis

Anterior and posterior blood supplies Anterior and posterior blood supplies are united by small communicating are united by small communicating arterial branchesarterial branches

Result—complete circle of connecting Result—complete circle of connecting blood vessels called blood vessels called cerebral arterial cerebral arterial circlecircle or or circle of Williscircle of Willis


Figure 11.14

Fetal CirculationFetal Circulation

Fetus receives exchanges of gases, Fetus receives exchanges of gases, nutrients, and wastes through the nutrients, and wastes through the placentaplacenta

Umbilical cord contains three vesselsUmbilical cord contains three vessels– Umbilical vein—carries blood rich in Umbilical vein—carries blood rich in

nutrients and oxygen to the fetusnutrients and oxygen to the fetus– Umbilical arteries (2)—carry carbon Umbilical arteries (2)—carry carbon

dioxide and debris-laden blood from dioxide and debris-laden blood from fetus to placentafetus to placenta


Blood flow bypasses the liver through the Blood flow bypasses the liver through the ductus venosus and enters the inferior ductus venosus and enters the inferior vena cava vena cava right atrium of heart right atrium of heart

Blood flow bypasses the lungs Blood flow bypasses the lungs – Blood entering right atrium is shunted directly Blood entering right atrium is shunted directly

into the left atrium through the foramen ovaleinto the left atrium through the foramen ovale– Ductus arteriosus connects the aorta and Ductus arteriosus connects the aorta and

pulmonary trunk (becomes ligamentum pulmonary trunk (becomes ligamentum arteriosum at birth)arteriosum at birth)


Figure 11.15

Hepatic Portal CirculationHepatic Portal Circulation

Veins of hepatic portal circulation drainVeins of hepatic portal circulation drain– Digestive organsDigestive organs– SpleenSpleen– Pancreas Pancreas

Hepatic portal vein carries this blood to Hepatic portal vein carries this blood to the liver the liver

Liver helps maintain proper glucose, fat, Liver helps maintain proper glucose, fat, and protein concentrations in bloodand protein concentrations in blood


Major vessels of hepatic portal Major vessels of hepatic portal circulationcirculation– Inferior and superior mesenteric veinsInferior and superior mesenteric veins– Splenic veinSplenic vein– Left gastric veinLeft gastric vein


Figure 11.16


Figure 11.17

PulsePulse

PulsePulse– Pressure wave of bloodPressure wave of blood

Monitored at “pressure points” in Monitored at “pressure points” in arteries where pulse is easily arteries where pulse is easily palpatedpalpated

Pulse averages 70–76 beats per Pulse averages 70–76 beats per minute at restminute at rest

PulsePulse

Figure 11.18

Blood PressureBlood Pressure

Measurements by health professionals Measurements by health professionals are made on the pressure in large are made on the pressure in large arteriesarteries– Systolic—pressure at the peak of ventricular Systolic—pressure at the peak of ventricular

contraction contraction – Diastolic—pressure when ventricles relaxDiastolic—pressure when ventricles relax– Write systolic pressure first and diastolic last Write systolic pressure first and diastolic last

(120/80 mm Hg)(120/80 mm Hg) Pressure in blood vessels decreases as Pressure in blood vessels decreases as

distance from the heart increasesdistance from the heart increases

Comparison of Blood Comparison of Blood Pressures Pressures

in Different Vesselsin Different Vessels

Figure 11.19

Measuring Arterial Blood Measuring Arterial Blood PressurePressure

Figure 11.20a


Figure 11.20b


Figure 11.20c


Figure 11.20d

Blood Pressure: Effects of Blood Pressure: Effects of FactorsFactors

BP is blood pressureBP is blood pressure– BP is affected by age, weight, time of day, BP is affected by age, weight, time of day,

exercise, body position, emotional stateexercise, body position, emotional state CO is the amount of blood pumped out of the CO is the amount of blood pumped out of the

left ventricle per minuteleft ventricle per minute PR is peripheral resistance, or the amount of PR is peripheral resistance, or the amount of

friction blood encounters as it flows through friction blood encounters as it flows through vesselsvessels– Narrowing of blood vessels and increased blood Narrowing of blood vessels and increased blood

volume increases PRvolume increases PR BP = CO BP = CO PR PR


Neural factorsNeural factors– Autonomic nervous system adjustments Autonomic nervous system adjustments

(sympathetic division)(sympathetic division) Renal factorsRenal factors

– Regulation by altering blood volumeRegulation by altering blood volume– Renin—hormonal controlRenin—hormonal control


TemperatureTemperature– Heat has a vasodilating effectHeat has a vasodilating effect– Cold has a vasoconstricting effectCold has a vasoconstricting effect

ChemicalsChemicals– Various substances can cause increases Various substances can cause increases

or decreasesor decreases DietDiet

Factors Determining Blood Factors Determining Blood PressurePressure

Figure 11.21

Variations in Blood PressureVariations in Blood Pressure

Normal human range is variableNormal human range is variable– NormalNormal

140–110 mm Hg systolic140–110 mm Hg systolic 80–75 mm Hg diastolic80–75 mm Hg diastolic

– HypotensionHypotension Low systolic (below 110 mm HG)Low systolic (below 110 mm HG) Often associated with illnessOften associated with illness

– HypertensionHypertension High systolic (above 140 mm HG)High systolic (above 140 mm HG) Can be dangerous if it is chronicCan be dangerous if it is chronic

Capillary ExchangeCapillary Exchange

Substances exchanged due to Substances exchanged due to concentration gradientsconcentration gradients– Oxygen and nutrients leave the bloodOxygen and nutrients leave the blood– Carbon dioxide and other wastes leave Carbon dioxide and other wastes leave

the cellsthe cells

Capillary Exchange: Capillary Exchange: MechanismsMechanisms

Direct diffusion across plasma Direct diffusion across plasma membranesmembranes

Endocytosis or exocytosisEndocytosis or exocytosis Some capillaries have gaps Some capillaries have gaps

(intercellular clefts)(intercellular clefts)– Plasma membrane not joined by tight Plasma membrane not joined by tight

junctionsjunctions Fenestrations (pores) of some Fenestrations (pores) of some

capillariescapillaries

Capillary Exchange: Capillary Exchange: MechanismsMechanisms

Figure 11.22

Fluid Movements at Fluid Movements at Capillary BedsCapillary Beds

Blood pressure forces fluid and solutes out Blood pressure forces fluid and solutes out of capillariesof capillaries

Osmotic pressure draws fluid into Osmotic pressure draws fluid into capillariescapillaries

Blood pressure is higher than osmotic Blood pressure is higher than osmotic pressure at the arterial end of the capillary pressure at the arterial end of the capillary bedbed

Blood pressure is lower than osmotic Blood pressure is lower than osmotic pressure at the venous end of the capillary pressure at the venous end of the capillary bedbed

Fluid Movements at Fluid Movements at Capillary BedsCapillary Beds

Figure 11.23

Developmental Aspects of Developmental Aspects of the Cardiovascular Systemthe Cardiovascular System

A simple “tube heart” develops in the A simple “tube heart” develops in the embryo and pumps by the fourth embryo and pumps by the fourth weekweek

The heart becomes a four-The heart becomes a four-chambered organ by the end of chambered organ by the end of seven weeksseven weeks

Few structural changes occur after Few structural changes occur after the seventh weekthe seventh week

Developmental Aspects of Developmental Aspects of the Cardiovascular Systemthe Cardiovascular System

Aging problems associated with the Aging problems associated with the cardiovascular system includecardiovascular system include– Venous valves weakenVenous valves weaken– Varicose veinsVaricose veins– Progressive atherosclerosisProgressive atherosclerosis– Loss of elasticity of vessels leads to Loss of elasticity of vessels leads to

hypertensionhypertension– Coronary artery disease results from Coronary artery disease results from

vessels filled with fatty, calcified depositsvessels filled with fatty, calcified deposits

the circulatory system “pump it”. the cardiovascular system a closed system of the heart and...

Documents

heart wallfigure

cthe heart

heart relaxation

atriathe heart

layers of pericardiumthe

av valvesav valves openafigure

av valve flaps

valvesallow blood