The Heart and The Heart and

Circulatory Circulatory SystemSystem

• Our circulation Our circulation is a “double is a “double loop”.loop”.

• Blood must Blood must pass through pass through the heart twice the heart twice in order to in order to complete the complete the circuit.circuit.

THE HEARTTHE HEART

• The APEX of the heart is where the APICAL The APEX of the heart is where the APICAL HEARTBEAT can be heart. It is in the 5HEARTBEAT can be heart. It is in the 5thth intercostal space, about 4” (10 cm) to the intercostal space, about 4” (10 cm) to the left, midclavicular.left, midclavicular.

• The superior left corner is deep to costal The superior left corner is deep to costal cartilage #2, 1” to the left of midsternum.cartilage #2, 1” to the left of midsternum.

• The inferior right corner is 1” to the right The inferior right corner is 1” to the right of midsternal, deep to costal cartilage #6.of midsternal, deep to costal cartilage #6.

• The final placement of the heart The final placement of the heart would require an axis placed:would require an axis placed:

1.1. Tilted to the leftTilted to the left

2.2. Tilted anteriorlyTilted anteriorly

3.3. Rotated so the anterior side is to Rotated so the anterior side is to the left.the left.

Heart ChambersHeart Chambers

• Anatomically, the heart has 4 Anatomically, the heart has 4 chambers.chambers.

• Functionally, the heart has 2 Functionally, the heart has 2 chambers or pump circuits.chambers or pump circuits.

• The top chambers are ATRIA The top chambers are ATRIA (singular-atrium).(singular-atrium).

• The bottom chambers are The bottom chambers are VENTRICLES.VENTRICLES.

• The walls of the atrium are much The walls of the atrium are much thinner compared with the ventricles.thinner compared with the ventricles.

• Topograhically, there is a small flap Topograhically, there is a small flap of tissue called the AURICLE.of tissue called the AURICLE.

• Connected to the chambers are large Connected to the chambers are large vessels: vena cavae, pulmonary vessels: vena cavae, pulmonary arteries or trunk, pulmonary veins, arteries or trunk, pulmonary veins, and the aorta.and the aorta.

1.1. Right AuricleRight Auricle

2. 2. Right VentricleRight Ventricle

3. 3. Brachiocephalic Artery Brachiocephalic Artery (Oxygenated)(Oxygenated)

4.4. Aortic Arch Aortic Arch (Oxygenated)(Oxygenated)

5.5. Pulmonary Artery Pulmonary Artery (Deoxygenated)(Deoxygenated)

6.6. Left AuricleLeft Auricle

7.7. Interventricular SulcusInterventricular Sulcus

8.8. Left VentricleLeft Ventricle

Sheep Heart – Anterior View

11..

Brachiocephalic Brachiocephalic Artery (Oxygenated)Artery (Oxygenated)

22. .

Aortic Arch Aortic Arch (Oxygenated)(Oxygenated)

33. .

Openings for Openings for Pulmonary Veins Pulmonary Veins (Oxygenated)(Oxygenated)

44..

Opening for Inferior Opening for Inferior Vena Cava Vena Cava (Deoxygenated)(Deoxygenated)

55..

Left VentricleLeft Ventricle

66..

Opening for Superior Opening for Superior Vena Cava Vena Cava (Deoxygenated)(Deoxygenated)

77..

Right AuricleRight Auricle

88..

Right VentricleRight Ventricle

• If we look at the heart from the If we look at the heart from the anterior side, we the right side of the anterior side, we the right side of the heart.heart.

• Blood returns to the heart (right Blood returns to the heart (right atrium) via the SUPERIOR and atrium) via the SUPERIOR and INFERIOR VENA CAVAE and INFERIOR VENA CAVAE and CORONARY SINUS.CORONARY SINUS.

• From the right atrium From the right atrium it is pumped into the it is pumped into the RIGHT VENTRICLE.RIGHT VENTRICLE.

• It must pass through It must pass through the TRICUSPID VALVE the TRICUSPID VALVE (which has 3 cusps) (which has 3 cusps) which is a which is a ATRIOVENTRICULAR ATRIOVENTRICULAR VALVE.VALVE.

• From the right ventricle, the blood From the right ventricle, the blood then passes through the PULMONARY then passes through the PULMONARY SEMILUNAR VALVE and into the SEMILUNAR VALVE and into the PULMONARY TRUNK.PULMONARY TRUNK.

• The pulmonary trunk carries blood to The pulmonary trunk carries blood to the lungs for re-oxygenation in the the lungs for re-oxygenation in the alveoli.alveoli.

• All the valves are made of connective All the valves are made of connective tissue and function to prevent tissue and function to prevent backflow of blood.backflow of blood.

• Problems with the valves cause a Problems with the valves cause a disorder called PROLAPSE or disorder called PROLAPSE or MURMUR.MURMUR.

• Blood returns to the Blood returns to the LEFT ATRIUM via the LEFT ATRIUM via the PULMONARY VEINS.PULMONARY VEINS.

• There are 2 pulmonary There are 2 pulmonary veins from each lung.veins from each lung.

• The blood next passes The blood next passes through the BISCUPID through the BISCUPID (2 cusps) or MITRAL (2 cusps) or MITRAL VALVE on its way to VALVE on its way to the LEFT VENTRICLE.the LEFT VENTRICLE.

• From the left ventricle, blood passes From the left ventricle, blood passes through the AORTIC SEMILUNAR VALVE through the AORTIC SEMILUNAR VALVE into the AORTA.into the AORTA.

• To remember that the TRICUSPID VALVE To remember that the TRICUSPID VALVE comes before the BICUSPID VALVE, comes before the BICUSPID VALVE, remember the saying:remember the saying:

“ “Try before you buy”Try before you buy”

VALVESVALVES

• The valves open passively during The valves open passively during ventricular relaxation.ventricular relaxation.

• They close passively during They close passively during ventricular contraction.ventricular contraction.

• The CHORDAE TENDINEAE connect The CHORDAE TENDINEAE connect the edge of the AV valve to the the edge of the AV valve to the PAPILLARY MUSCLE.PAPILLARY MUSCLE.

Chordae tendinae

• These muscles prevent the valves These muscles prevent the valves from being forced closed in reverse.from being forced closed in reverse.

• The chords contract when the The chords contract when the papillary muscles pull on them.papillary muscles pull on them.

• The papillary muscles DO NOT cause The papillary muscles DO NOT cause the valves to open or close.the valves to open or close.

• The SEMILUNAR VALVES are found The SEMILUNAR VALVES are found between the ventricles and the large between the ventricles and the large arteries leaving the ventricles.arteries leaving the ventricles.

• They are TRICUSPID in structure. They are TRICUSPID in structure. Heart sounds are caused by the Heart sounds are caused by the closing of these valves.closing of these valves.

The Semilunar ValvesThe Semilunar Valves

1

2

3

• SUMMARY:SUMMARY:

4 chambers4 chambers4 valves4 valves4 vessels4 vessels

ARTERIES=carry blood AWAY from the heart.ARTERIES=carry blood AWAY from the heart.VEINS = carry blood TOWARD the heart.VEINS = carry blood TOWARD the heart.

1. Right Coronary 2. Left Anterior Descending 3. Left Circumflex 4. Superior Vena Cava 5. Inferior Vena Cava 6. Aorta 7. Pulmonary Artery 8. Pulmonary Vein

9. Right Atrium 10. Right Ventricle 11. Left Atrium 12. Left Ventricle 13. Papillary Muscles 14. Chordae Tendineae 15. Tricuspid Valve 16. Mitral Valve 17. Pulmonary Valve

CIRCULATIONCIRCULATION

• The importance of circulation is the The importance of circulation is the movement of materials into and out of the movement of materials into and out of the cells.cells.

• Cells require O2 and need to get rid of Cells require O2 and need to get rid of CO2.CO2.

• This is accomplished by two processes: This is accomplished by two processes: BULK FLOW and DIFFUSION.BULK FLOW and DIFFUSION.

Bulk FlowBulk Flow

• Bulk flow is the movement of blood Bulk flow is the movement of blood over significant distances in a short over significant distances in a short period of time. Accomplished by period of time. Accomplished by pressure gradients.pressure gradients.

• Blood moves from areas of high Blood moves from areas of high pressure to areas of low pressure.pressure to areas of low pressure.

• We establish pressure gradients by We establish pressure gradients by using:using:

1. heart1. heart

2. gravity2. gravity

3. skeletal muscle3. skeletal muscle

4. smooth muscle4. smooth muscle

DiffusionDiffusion

• Diffusion is the random movement of Diffusion is the random movement of molecules with net movement from molecules with net movement from areas of high concentration to areas areas of high concentration to areas of low concentration.of low concentration.

• It is only effective over short It is only effective over short distances.distances.

• It only happens in capillaries.It only happens in capillaries.

• This can happen because capillaries This can happen because capillaries are blood vessels that are only one are blood vessels that are only one cell thick.cell thick.

• Capillaries are the FUNCTIONAL UNIT Capillaries are the FUNCTIONAL UNIT of circulation with the cells.of circulation with the cells.

• The circulatory system is a CLOSED The circulatory system is a CLOSED SYSTEM with three main SYSTEM with three main components:components:

1. heart (bulk flow)1. heart (bulk flow)

2. vessels (direct flow)2. vessels (direct flow)

3. blood (used for transport)3. blood (used for transport)

Path of CirculationPath of Circulation

Heart -> arteries -Heart -> arteries -> arterioles -> > arterioles -> capillaries -> capillaries -> venules -> veins venules -> veins -> heart-> heart

• Arterioles are small arteries and have Arterioles are small arteries and have a lumen diameter of about 0.5 mm. a lumen diameter of about 0.5 mm. Their anatomy is the same as Their anatomy is the same as arteries.arteries.

Anatomy of an ArteryAnatomy of an Artery

Lumen

Tunica Intima-inner lining – endothelia and CT

Tunica Media – middle smooth muscular layer – thick in arteries, thin in veins

Tunica Aventitia or Tunica Externa - contain CT and Vaso Vasorum

Fibrous tissue layer

• Recall that the arteries have a muscular Recall that the arteries have a muscular pump to help blood get to the needed pump to help blood get to the needed body parts.body parts.

• Veins do not have this pump.Veins do not have this pump.• Skeletal muscle contractions help move Skeletal muscle contractions help move

the blood upward toward the heart. Also, the blood upward toward the heart. Also, veins have VALVES which prevent veins have VALVES which prevent backflow of blood (gravity)backflow of blood (gravity)

• When blood cannot travel back When blood cannot travel back toward the heart, it can accumulate toward the heart, it can accumulate in the veins. This causes a dilation of in the veins. This causes a dilation of the vein, or VARICOSE VEINS.the vein, or VARICOSE VEINS.

In ReviewIn Review

VEINS ARTERIESVEINS ARTERIES1.1. Toward heart Toward heart CARRY BLOODCARRY BLOOD Away from heart Away from heart2.2. 2-3 cells thick2-3 cells thick MUSCULAR LAYERMUSCULAR LAYER 40 cells thick40 cells thick

3.3. Semilunar Valves Semilunar Valves VALVESVALVES No valves No valves

4.4. Decreased Decreased OXYGEN LEVELSOXYGEN LEVELS Increased Increased

Categories of CirculationCategories of Circulation

1.1. Pulmonary Circulation-Pulmonary Circulation- Blood from right ventricle goes Blood from right ventricle goes

through the pulmonary trunk to through the pulmonary trunk to lungs and back to left atrium.lungs and back to left atrium.

• There is much lower hydrostatic There is much lower hydrostatic pressure than in the systemic pressure than in the systemic circulation.circulation.

• 2. Systemic Circulation2. Systemic Circulation

The second major circulatory loop. Blood The second major circulatory loop. Blood leaves the left ventricle and is pumped leaves the left ventricle and is pumped throughout the body. It ends up in the throughout the body. It ends up in the right atrium.right atrium.

This loop includes blood supply to the GI This loop includes blood supply to the GI tract to help with nutrient absroption.tract to help with nutrient absroption.

Collateral CirculationCollateral Circulation

• Allows blood to flow around a blockage.Allows blood to flow around a blockage.• Arterioles meet head on in an ANASTOMOSIS.Arterioles meet head on in an ANASTOMOSIS.• Anastomoses serve as a natural bypass.Anastomoses serve as a natural bypass.

Portal CirculationPortal Circulation

• Veins from pancreas, spleen, small Veins from pancreas, spleen, small intestine, and stomach empty into intestine, and stomach empty into the portal vein in the liver.the portal vein in the liver.

• After excess glucose is removed and After excess glucose is removed and detoxification occurs, blood enters detoxification occurs, blood enters the hepatic portal vein to be returned the hepatic portal vein to be returned to the vena cava and the general to the vena cava and the general circulation.circulation.

Fetal CirculationFetal Circulation

- needed because the fetal lung is not - needed because the fetal lung is not functional. Fetal oxygen source is the functional. Fetal oxygen source is the PLACENTA.PLACENTA.

- blood from mother and fetus do not mix, - blood from mother and fetus do not mix, but rather is in 2 adjacent capillary beds.but rather is in 2 adjacent capillary beds.

- permeable materials can pass through - permeable materials can pass through the adjacent capillary beds causing the the adjacent capillary beds causing the fetus to be exposed to whatever is in the fetus to be exposed to whatever is in the mother’s bloodstream.mother’s bloodstream.

Blood flows from the placenta to the fetus Blood flows from the placenta to the fetus via on UMBILICAL VEIN.via on UMBILICAL VEIN.

- The UV has the most oxygen rich blood - The UV has the most oxygen rich blood for the fetus.for the fetus.

- This vein branches with one part going - This vein branches with one part going to the FETAL LIVER and the other going to to the FETAL LIVER and the other going to the INFERIOR VENA CAVAE (DUCTUS the INFERIOR VENA CAVAE (DUCTUS VENOSIS).VENOSIS).

- Blood then enters the right atrium. - Blood then enters the right atrium. Blood so far is MIXED (both oxygenated Blood so far is MIXED (both oxygenated and deoxygenated).and deoxygenated).

• This blood is then combined with This blood is then combined with deoxygenated blood from the coronary deoxygenated blood from the coronary sinus and superior vena cavae.sinus and superior vena cavae.

• There is a hole (foramen) between the There is a hole (foramen) between the atria. This is called the FORAMEN atria. This is called the FORAMEN OVALE.OVALE.

• There is also a linkage between the There is also a linkage between the pulmonary artery and the aorta. This pulmonary artery and the aorta. This is called the DUCTUS ARTERIOSUS.is called the DUCTUS ARTERIOSUS.

• The UMBILICAL ARTERIES branch The UMBILICAL ARTERIES branch from the INTERNAL ILIAC ARTERIES from the INTERNAL ILIAC ARTERIES found in the pelvis. The ILA’s are found in the pelvis. The ILA’s are branches of the COMMON ILIAC branches of the COMMON ILIAC ARTERIES which are the terminal ARTERIES which are the terminal branches of the aorta.branches of the aorta.

Coronary CirculationCoronary Circulation

- heart has a separate circulation.- heart has a separate circulation. - these coronary vessels are the ones - these coronary vessels are the ones

treated in “bypass” surgery.treated in “bypass” surgery. - CORONARY SULCUS or - CORONARY SULCUS or

ATRIOVENTRICULAR GROOVE ATRIOVENTRICULAR GROOVE - INTERVENTRICULAR SULCUS.- INTERVENTRICULAR SULCUS. - The coronary arteries and veins are - The coronary arteries and veins are

located within these grooves.located within these grooves.

Coronary Circulation

• Each blood cell must pass through Each blood cell must pass through the heart twice in order to complete the heart twice in order to complete a full circulatory circuit.a full circulatory circuit.

Lymphatics (in general)Lymphatics (in general)

• The lymphatic system is a system that collects The lymphatic system is a system that collects and recycles fluids that have leaked from the and recycles fluids that have leaked from the circulation. It is also involved in fighting circulation. It is also involved in fighting infections.infections.

• It is made of a series of LYMPH VESSELS and tiny It is made of a series of LYMPH VESSELS and tiny bean-shaped NODES.bean-shaped NODES.

• Lymph tissue is located in various parts of the Lymph tissue is located in various parts of the body including; thymus, tonsils, spleen, and bone body including; thymus, tonsils, spleen, and bone marrow.marrow.

• The lymph tissue is eventually drained into the The lymph tissue is eventually drained into the vena cava to go into the right atrium.vena cava to go into the right atrium.

What is carried in the What is carried in the blood?blood?• Respiratory gasses (oxygen and CO2)Respiratory gasses (oxygen and CO2)

• NutrientsNutrients

• HormonesHormones

• Defense cells/Immune cellsDefense cells/Immune cells

• Repair cellsRepair cells

It also regulates body temperature by It also regulates body temperature by carrying warmth from the center of the carrying warmth from the center of the body to the periphery.body to the periphery.

Blood AnatomyBlood Anatomy

• Blood is composed Blood is composed of two parts.of two parts.

1. FORMED 1. FORMED ELEMENTSELEMENTS

- cellular component- cellular component

2. PLASMA2. PLASMA - - liquid componentliquid component

CentrifugeCentrifuge

• Machine which spins tubes of blood Machine which spins tubes of blood to separate the components.to separate the components.

RBC’s

WBC’s BUFFY COAT

Plasma

PlasmaPlasma

• A straw-colored, sticky fluid.A straw-colored, sticky fluid.

• Contains over 100 different kinds of molecules.Contains over 100 different kinds of molecules.

• Contains three proteins:Contains three proteins:

a. Albumin – important in keeping osmotic a. Albumin – important in keeping osmotic pressure constant. Also important in wound pressure constant. Also important in wound healing.healing.

b. Globulins – important for antibody b. Globulins – important for antibody production and transport of other molecules.production and transport of other molecules.

c. Fibrinogen – important for blood clottingc. Fibrinogen – important for blood clotting

Formed ElementsFormed Elements

• These are the “blood cells”These are the “blood cells”

1.1. ErythrocytesErythrocytes

a. RBC’sa. RBC’s

b. Carry oxygenb. Carry oxygen

c. No nuclei or organellesc. No nuclei or organelles

d. % of blood volume that contain d. % of blood volume that contain erythrocytes is known as the erythrocytes is known as the HEMATOCRIT.HEMATOCRIT.

e. cytoplasm is filled with HEMOGLOBIN.e. cytoplasm is filled with HEMOGLOBIN. f. Hemoglobin is the oxygen carrying protein.f. Hemoglobin is the oxygen carrying protein. g. Pick up oxygen in the lung capillaries and release g. Pick up oxygen in the lung capillaries and release

carbon dioxide.carbon dioxide. h. Spherical shapedh. Spherical shaped i. When the shaped changes, individual cells have i. When the shaped changes, individual cells have

difficulty entering and traveling through the capillary difficulty entering and traveling through the capillary lumen.lumen.

j. Efficient oxygen transporters as they do not use any j. Efficient oxygen transporters as they do not use any of the oxygen they transport. This is because they do of the oxygen they transport. This is because they do not have organelles (mitochondria). The erythrocytes not have organelles (mitochondria). The erythrocytes must get their energy through anaerobic means. must get their energy through anaerobic means.

k. Live for 120 days. Therefore, it is k. Live for 120 days. Therefore, it is easy to use them for clinical testing. For easy to use them for clinical testing. For example, glucose binds to the RBC. The example, glucose binds to the RBC. The more glucose that is bound to the RBC, more glucose that is bound to the RBC, the higher the patients average blood the higher the patients average blood sugar levels. HbA1C is a measurement sugar levels. HbA1C is a measurement of how much sugar is bound to the RBC. of how much sugar is bound to the RBC. If this test is performed every 120 days, If this test is performed every 120 days, physicians can determine the range of physicians can determine the range of blood sugar control.blood sugar control.

LEUKOCYTESLEUKOCYTES

• White Blood Cells (WBC)White Blood Cells (WBC)• Crucial to the bodies defense against disease.Crucial to the bodies defense against disease.• Have all the organelles and nuclei of a true cell.Have all the organelles and nuclei of a true cell.• Leukocytes perform their function outside the Leukocytes perform their function outside the

circulatory system. They function in the connective circulatory system. They function in the connective tissue (where infections usually occur).tissue (where infections usually occur).

• When a leukocyte senses an infection, it moves out of When a leukocyte senses an infection, it moves out of the circulation by squeezing out between the the circulation by squeezing out between the endothelial cells which line the blood vessels. This is endothelial cells which line the blood vessels. This is known as DIAPEDESIS.known as DIAPEDESIS.

• Once outside the circulation, the WBC’s use Once outside the circulation, the WBC’s use amoeboid motion to find the offending organism.amoeboid motion to find the offending organism.

5 Types of Leukocytes5 Types of Leukocytes

Granulocytes Granulocytes 1. Neutrophils – most abundant1. Neutrophils – most abundant - lobuated nuclei- lobuated nuclei - “Polymorphonuclear - “Polymorphonuclear Leukocytes” (PMN’s)Leukocytes” (PMN’s) - “Polys” or “Segs”- “Polys” or “Segs” - phagocytize and - phagocytize and destroy bacteria. destroy bacteria.

2.2. EosinophilsEosinophils

- rarely found- rarely found

- nuclei with only 2 lobes- nuclei with only 2 lobes

- stain red with acidic dye “Eosin”- stain red with acidic dye “Eosin”

- fight parasites and parasitic - fight parasites and parasitic diseasesdiseases

3.3. BasophilsBasophils

- rarest of all WBC’s- rarest of all WBC’s

- nuclei stain dark with basic stain- nuclei stain dark with basic stain

- secrete histamine to mediate - secrete histamine to mediate allergic reactions.allergic reactions.

• AgranulocytesAgranulocytes 1. Lymphocytes1. Lymphocytes - most important cell in the immune system- most important cell in the immune system - function in the connective tissue, not the - function in the connective tissue, not the

bloodstreambloodstream - important for fighting infection- important for fighting infection - substances that cause a reaction from a - substances that cause a reaction from a

lymphocyte is called an ANTIGEN.lymphocyte is called an ANTIGEN. - 2 types of lymphocytes: T-cells (kill - 2 types of lymphocytes: T-cells (kill

organisms directly)organisms directly) B-cells (become mast B-cells (become mast

cellscells

2.2. MonocytesMonocytes

- become macrophages which - become macrophages which ingest a wide variety of foreign ingest a wide variety of foreign debrisdebris

CLINICAL CORELLATIONCLINICAL CORELLATION

A complete blood count (CBC)A complete blood count (CBC)

- Quantifies the various cell types Quantifies the various cell types found in the blood.found in the blood.

- A DIFFERENTIAL identifies the A DIFFERENTIAL identifies the percentage of each type of percentage of each type of leukocyte. leukocyte.

PlateletsPlatelets

• Known as THROMBOCYTESKnown as THROMBOCYTES• Function to plug small tears in the walls of Function to plug small tears in the walls of

the blood vessels to limit bleeding.the blood vessels to limit bleeding.• Adhere to exposed collagen at the edges of Adhere to exposed collagen at the edges of

a tear.a tear.• Release THROMBOPLASTIN, a molecule that Release THROMBOPLASTIN, a molecule that

initates clotting.initates clotting.• Platelets adhere only to damaged blood Platelets adhere only to damaged blood

vessels. When a clot develops or persists in vessels. When a clot develops or persists in an intact blood vessel, a THROMBUS results. an intact blood vessel, a THROMBUS results.