Blood and CirculationBlood and Circulation(Cardiovascular (Cardiovascular

System)System)

BloodBloodFunctions:Functions:

Transports material between body cells and Transports material between body cells and external environmentexternal environment

oxygen for CR, carbon dioxide away, nutrients, oxygen for CR, carbon dioxide away, nutrients, ions, hormones, immune cells and antibodiesions, hormones, immune cells and antibodies

Distributes heatDistributes heat Protection of the body by white blood cells Protection of the body by white blood cells

and antibodies that circulate in the blood and antibodies that circulate in the blood and defend the body against foreign and defend the body against foreign material.material.

Clotting mechanisms are also present that Clotting mechanisms are also present that protect the body from blood loss after protect the body from blood loss after injuries.injuries.

Preview Blood Composition

Blood – Blood – Erythro (red) Hema – Erythro (red) Hema – (blood)(blood)

I. Connective tissue – cells in a liquid I. Connective tissue – cells in a liquid matrix matrix ~5-6 L/person (8% of body weight)~5-6 L/person (8% of body weight)

What would having a greater percent of RBCs mean?

Who would this benefit? Where have you seen this in the news lately?

Hematocrit% of RBCs

What Could You Tell From Giving What Could You Tell From Giving Blood?Blood?

Blood dopingBlood doping HydrationHydration Blood diseasesBlood diseases

AnemiaAnemia PolycythemiaPolycythemia LeukemiaLeukemia

DiabeticDiabetic PregnantPregnant

Blood DiseasesBlood Diseases LeukemiaLeukemia – over production of WBC’s – immature – over production of WBC’s – immature

and don’t work – metastasize to liver, spleen – use up and don’t work – metastasize to liver, spleen – use up all metabolic substrates and cause tissue destructionall metabolic substrates and cause tissue destruction

PolycythemiaPolycythemia – bone marrow cancer – make too – bone marrow cancer – make too many RBC’smany RBC’s

AnemiaAnemia – deficiency of RBC’s or hemoglobin – deficiency of RBC’s or hemoglobin (decreased O2 carrying ability)(decreased O2 carrying ability) Sickle cell anemia – genetic point mutation in hemoglobinSickle cell anemia – genetic point mutation in hemoglobin Aplastic Anemia – cancer – can’t produce RBC’sAplastic Anemia – cancer – can’t produce RBC’s Iron Deficiency AnemiaIron Deficiency Anemia

HemophiliaHemophilia – lack of a clotting factor – blood clots – lack of a clotting factor – blood clots slowly on internal bleeds – 1 hour vs. 6-8 minutesslowly on internal bleeds – 1 hour vs. 6-8 minutes

Blood CompositionBlood Composition

A. Plasma (Liquid ECM) – 54%A. Plasma (Liquid ECM) – 54% HH22O (92%)O (92%) Proteins Proteins

Fibrinogen - clotting Fibrinogen - clotting Globulins - antibodiesGlobulins - antibodies Albumin - osmotic balance b/w blood and other tissueAlbumin - osmotic balance b/w blood and other tissue Others – hormones, enzymesOthers – hormones, enzymes

Nutrients: Monomers - aa, glucose, fatty acids, nucleic Nutrients: Monomers - aa, glucose, fatty acids, nucleic acids, and vitamins from digested foodacids, and vitamins from digested food

Salts (electrolytes or ions) - maintain pH 7.35-7.45, Salts (electrolytes or ions) - maintain pH 7.35-7.45, osmotic balance, need for muscle contractionosmotic balance, need for muscle contraction

Cellular waste (COCellular waste (CO22, N, N22) and O) and O22

Blood Composition Cont.Blood Composition Cont.B. Formed Elements (Cells)B. Formed Elements (Cells)

1. RBC’s (erythrocytes) – 45%1. RBC’s (erythrocytes) – 45% has iron containing protein, hemoglobin that turns red when has iron containing protein, hemoglobin that turns red when

binds with Obinds with O22 and transports, also helps to remove CO and transports, also helps to remove CO22 Misconception: Blood in your veins is not blue. It has very

little oxygen and is a dark red color that looks almost blue when covered by your skin.

lasts 120 days circulating body ~75,000 timeslasts 120 days circulating body ~75,000 times have no nucleus so can’t divide, replaced mainly by bone have no nucleus so can’t divide, replaced mainly by bone

marrow in flat bones and epiphyses of long bonesmarrow in flat bones and epiphyses of long bones Shape is biconcave which increases surface area available Shape is biconcave which increases surface area available

to carry Oto carry O22 and no nucleus allows to be flexible to squeeze and no nucleus allows to be flexible to squeeze through narrow capillariesthrough narrow capillaries

No mitochondria so don’t use the ONo mitochondria so don’t use the O22 they carry they carry

Blood Cell Formation Blood Cell Formation (Hematopoiesis)(Hematopoiesis) Forms from hematopoietic stem cells in red bone Forms from hematopoietic stem cells in red bone

marrow of flat bones and ends of long bonesmarrow of flat bones and ends of long bones Erythropoietin (EPO)Erythropoietin (EPO) - hormone produced by the - hormone produced by the

kidney maintains homeostasis by controlling RBC kidney maintains homeostasis by controlling RBC productionproduction Low OLow O2 2 from high altitude, loss of blood (Natural or blood from high altitude, loss of blood (Natural or blood

doping), lung diseases causes release of erythropoietin doping), lung diseases causes release of erythropoietin from kidney and liver from kidney and liver increases RBC production increases RBC production better oxygen carrying capability better oxygen carrying capability shuts off release of shuts off release of erythropoietin (negative feedback loop)erythropoietin (negative feedback loop)

Blood Composition Blood Composition ContinuedContinued

B. Formed Elements (Cells)B. Formed Elements (Cells)2. WBC’s (leukocytes) – 1%2. WBC’s (leukocytes) – 1% Names are derived from staining processNames are derived from staining process

Live for about 3-4 days or yearsLive for about 3-4 days or years Immune Cells - protect against infection in various waysImmune Cells - protect against infection in various ways

Phagocytes (engulf bacterial cells)Phagocytes (engulf bacterial cells) Produce antibodiesProduce antibodies

Found in blood and transported to sites of infection Found in blood and transported to sites of infection (immune system) and in lymphatic system and in lymphatic system

Blood Composition Blood Composition ContinuedContinued

a.a. GranulocytesGranulocytes – made in bone marrow, – made in bone marrow, names are based on when stained names are based on when stained

theythey look look granular, non-specific, life span granular, non-specific, life span ~12 hrs~12 hrs

1. Neutrophils1. Neutrophils – phagocytes (engulfs – phagocytes (engulfs bacteria only), 1bacteria only), 1stst responders, wound responders, wound healing, dead cells are found as puss at healing, dead cells are found as puss at sites of infectionsites of infection

2. Basophils2. Basophils – (mast cells) release – (mast cells) release histamine which promotes inc. blood flow histamine which promotes inc. blood flow which causes swelling/inflammation, which causes swelling/inflammation, excess histamine = allergic reactions, excess histamine = allergic reactions, signals for more spec macrophages to signals for more spec macrophages to come to infected site to catch pathogenscome to infected site to catch pathogens

3. Eosinophils3. Eosinophils - fights parasites - fights parasites

Blood composition ContinuedBlood composition Continuedb. b. AgranulocytesAgranulocytes made in bone made in bone

marrow, names are based on when marrow, names are based on when stained they lack granulesstained they lack granules1. 1. MonocytesMonocytes – body’s vacuum cleaner, – body’s vacuum cleaner, when activated become when activated become macrophagesmacrophages (a (a wandering phagocytic cell that destroys wandering phagocytic cell that destroys large amounts of bacteria or damaged large amounts of bacteria or damaged tissue), non-specific, secrete hormone tissue), non-specific, secrete hormone (cytokines) to signal more specific WBCs, (cytokines) to signal more specific WBCs, life span several weeks to monthlife span several weeks to month

Blood composition Blood composition ContinuedContinued

2. 2. LymphocytesLymphocytes – made in lymph glands – made in lymph glands (lymphatic system), spleen, and (lymphatic system), spleen, and thymus; thymus; specific immunity, life span years (slow working specific immunity, life span years (slow working to create antibodies – reason for vaccines)to create antibodies – reason for vaccines)

B cells B cells – make antibodies (proteins that attack – make antibodies (proteins that attack foreign molecules), clumps bacteria pathogens to foreign molecules), clumps bacteria pathogens to be eaten by macrophagesbe eaten by macrophages

T cells T cells - Cytotoxic – “killers” – kill infected cells from - Cytotoxic – “killers” – kill infected cells from viruses, cancerous tumor cells, transplanted cells viruses, cancerous tumor cells, transplanted cells (anything foreign)(anything foreign)

Analogy: Invasion in building – protect halls vs. Analogy: Invasion in building – protect halls vs. classroomsclassrooms

T cells T cells – “Helper” – increase B cells and T killers– “Helper” – increase B cells and T killers

WBC: Specific vs. Non-WBC: Specific vs. Non-SpecificSpecific

Non-Specific (Granulocytes, Monocytes)

Specific (Lymphocytes)

No receptors Cells have own receptors that recognize marker protein on pathogen entering body

Quick response (EMT first responders

Slow response (specialized Dr.)

Less effective, help keep the infection under control

More effective, knock the infection out

Reason for vaccinations

Blood Composition ContinuedBlood Composition Continued

Relative Abundance of WBC’s:Relative Abundance of WBC’s: Neutrophils (60-70 %), Lymphocytes Neutrophils (60-70 %), Lymphocytes

(20%), Monocytes (6%), Eosinophils (20%), Monocytes (6%), Eosinophils (3%), Basophils (<1%)(3%), Basophils (<1%)

Never Let Monkeys Eat BananasNever Let Monkeys Eat Bananas Important to determine blood Important to determine blood

disordersdisorders

WBCs all Defend the Body. What WBCs all Defend the Body. What Order?Order?

Leukocytes are recruited and activated by cell Leukocytes are recruited and activated by cell damage or foreign tissuedamage or foreign tissue NeutrophilsNeutrophils are first responders at site of injury are first responders at site of injury BasophilsBasophils – triggered next to release histamine – triggered next to release histamine

and increase blood flowand increase blood flow MacrophagesMacrophages are always roaming around the body. are always roaming around the body. CytokinesCytokines (chemical attractors of more specific (chemical attractors of more specific

WBC’s) are released by WBC’s) are released by T helpers T helpers and and macrophagesmacrophages. Activates . Activates lymphocyteslymphocytes (T killers (T killers and B cells).and B cells).

Leukocytes leave the blood circulation by squeezing through the walls of the blood vessels, travel through the interstitial space and enter the site of injury.

basophils

lymphocytes

Blood composition ContinuedBlood composition Continued

3. 3. PlateletsPlatelets (Thrombocytes) – small fragments of (Thrombocytes) – small fragments of larger shattered cells, arise from bone marrow, larger shattered cells, arise from bone marrow, life span ~ 10 dayslife span ~ 10 days Blood clotting (Hemostasis) – 2 to 6 min.Blood clotting (Hemostasis) – 2 to 6 min.

release release serotoninserotonin which helps to reduce blood loss from which helps to reduce blood loss from broken vessels by contracting smooth muscles in vessel walls broken vessels by contracting smooth muscles in vessel walls

release release thromoboplastinthromoboplastin, an enzyme that converts , an enzyme that converts prothrombin to thrombin during the early stages of blood prothrombin to thrombin during the early stages of blood coagulation.coagulation.

Thrombin linksThrombin links fibrinogen (small soluble fibrous proteins fibrinogen (small soluble fibrous proteins found in the plasma) found in the plasma) and it becomes and it becomes fibrinfibrin – which is large – which is large insoluble protein fibers that act like a mesh linking WBC’s insoluble protein fibers that act like a mesh linking WBC’s and RBC’s togetherand RBC’s together

Blood DiseasesBlood Diseases ThrombusThrombus – abnormal blood clot due to fatty – abnormal blood clot due to fatty

deposits/plaque build up in artery walls deposits/plaque build up in artery walls EmbolusEmbolus – clot that has broken off – can block – clot that has broken off – can block

blood supply to organs and may cause stroke or blood supply to organs and may cause stroke or death death

RBC Proteins (Blood Types)RBC Proteins (Blood Types) AntigenAntigen (antibody generator) or (antibody generator) or agglutinogenagglutinogen

– surface protein that induces an immune – surface protein that induces an immune response to make antibodies response to make antibodies Over 30 types of RBC proteinsOver 30 types of RBC proteins Most common – A, B, OMost common – A, B, O Rh factor – if present = positive blood (+), if Rh factor – if present = positive blood (+), if

missing = negative blood (–). missing = negative blood (–). It was originally found on the red blood cells of It was originally found on the red blood cells of

Rhesus monkeys (hence the “Rh” factor). Rhesus monkeys (hence the “Rh” factor). Also known as the D antigenAlso known as the D antigen

RBC Proteins (Blood Types)RBC Proteins (Blood Types)

AntibodyAntibody ( (agglutininagglutinin) – protein ) – protein produced by the immune system in produced by the immune system in response to the presence of an response to the presence of an antigen (Ex. Anti-A)antigen (Ex. Anti-A)

AgglutinationAgglutination – clumping of cells in – clumping of cells in response to specific antibodyresponse to specific antibody

Blood TypesBlood Types

(antigen)

Immune response is to make antibodiesagainst proteins(antigens) that areforeign to the body

Blood Type

Antigens on blood cells

Antibody body will make (foreign cells)

Person can donate to

Person can receive from

A

B

AB

O

+

-

Blood TypesBlood TypesBlood TypeBlood Type Antigens on Antigens on

blood cellsblood cellsBody will make Body will make

Ab againstAb against

(cells (cells considered considered

foreign)foreign)

Person Person can can

Donate Donate to:to:

Person can Person can Receive Receive From:From:

AA AA B, (B & AB)B, (B & AB) A, ABA, AB A, OA, O

BB BB A, (A & AB)A, (A & AB) B, ABB, AB B, OB, O

ABAB A AND BA AND B NONE (NONE)NONE (NONE) ABAB ALLALL

Universal Universal recipientrecipient

OO NONENONE ALLALL ALLALL

Universal Universal donordonor

OO

++ RhRh NONE (NONE)NONE (NONE) ++ + and -+ and -

__ NONENONE RhRh + and -+ and - --

Universal Donor & Universal Recipient

Blood Typing LabBlood Typing Lab

To determine blood type, add all types of antibodies and see To determine blood type, add all types of antibodies and see which will clot. In the lab, clotting means the antibody is which will clot. In the lab, clotting means the antibody is recognizing the antigen (surface protein) present on RBC. What recognizing the antigen (surface protein) present on RBC. What does clotting mean inside the body?does clotting mean inside the body?

Patient above is B-Patient above is B- What blood would be foreign to this patient and what antibody What blood would be foreign to this patient and what antibody

would they produce to cause clumping to rid the body of this would they produce to cause clumping to rid the body of this foreign blood?foreign blood?

Blood TransfusionsBlood Transfusions Various proteins are embedded in the surfaces of red blood cells, Various proteins are embedded in the surfaces of red blood cells,

these proteins are inherited. these proteins are inherited. If during a transfusion an individual receives blood containing If during a transfusion an individual receives blood containing

RBCs with proteins that the individual does not carry, these RBCs with proteins that the individual does not carry, these proteins are recognized as proteins are recognized as foreignforeign antigensantigens by the immune by the immune system. system.

AntibodiesAntibodies are produced and bind to the are produced and bind to the antigensantigens and cause and cause agglutinationagglutination ( (clumpingclumping) and subsequent destruction of the ) and subsequent destruction of the foreign RBCs foreign RBCs clumping allows macrophages to engulf cells and clumping allows macrophages to engulf cells and results in death.results in death.

For example, the immune system would respond if a person with For example, the immune system would respond if a person with A blood type (either AA or AO) receives blood from a person of B A blood type (either AA or AO) receives blood from a person of B or AB blood type, but not from an O type. (The O type does not or AB blood type, but not from an O type. (The O type does not carry any foreign antigens.)carry any foreign antigens.)

Cardiovascular SystemCardiovascular System FunctionFunction: sends oxygen : sends oxygen

rich blood and rich blood and nutrients to all body nutrients to all body cells and removes cells and removes wastewaste

Closed system or else Closed system or else you would bleed out.you would bleed out.

How do we get oxygen How do we get oxygen in the blood then?in the blood then?

Parts of Cardiovascular Parts of Cardiovascular SystemSystem

HeartHeart – cardiac muscular pump, – cardiac muscular pump, ~6000 quarts/day~6000 quarts/day Vessels Vessels – organs that form a closed circuit that – organs that form a closed circuit that

carries blood from heart to body cells and back carries blood from heart to body cells and back again.again. carries oxygen, nutrients, waste, regulate body temp carries oxygen, nutrients, waste, regulate body temp

and bp through vasodilation and vasoconstriction)and bp through vasodilation and vasoconstriction) Arteries, arterioles, capillaries Arteries, arterioles, capillaries – moves oxygenated blood – moves oxygenated blood

away from heart to deliver material to cellsaway from heart to deliver material to cells Veins, venules, capillariesVeins, venules, capillaries – returns deoxygenated blood to – returns deoxygenated blood to

the heartthe heart

CirculationCirculation(Closed System)(Closed System)

Heart Heart → Arteries → Arterioles →→ Arteries → Arterioles →

(less lumen and smooth muscle)(less lumen and smooth muscle)

Capillaries → Venules → Veins → HeartCapillaries → Venules → Veins → Heart (just epithelium)(just epithelium)

*Without circulation, tissues would lack a supply of *Without circulation, tissues would lack a supply of oxygen and nutrients. Waste would accumulate oxygen and nutrients. Waste would accumulate resulting in death.resulting in death.

Closed System of Blood CirculationClosed System of Blood Circulation Blood vessels form two Blood vessels form two

circuitscircuits Pulmonary Circuit Pulmonary Circuit

(between heart and lungs) (between heart and lungs) – sends oxygen-depleted – sends oxygen-depleted blood to the lungs to pick blood to the lungs to pick up Oup O2 2 and unload COand unload CO2 2

Systemic Circuit Systemic Circuit (between (between heart and rest of body)heart and rest of body)– – sends oxygen-rich blood sends oxygen-rich blood and nutrients to all body and nutrients to all body cells and removes wastescells and removes wastes

Blood Vessel StructureBlood Vessel Structure Basic blood vessel structure: arteries & veinsBasic blood vessel structure: arteries & veins

Internal lining (Tunica Intima)Internal lining (Tunica Intima) Simple Epithelium – endotheliumSimple Epithelium – endothelium

Prevents leakagePrevents leakage

Middle of wall (Tunica Media)Middle of wall (Tunica Media) Smooth muscleSmooth muscle

Squeezes blood through vesselSqueezes blood through vessel

Outside (Tunica Externa)Outside (Tunica Externa) Fibrous connective tissue (elastic and collagen)Fibrous connective tissue (elastic and collagen)

Protection/support/attaches vessel to surrounding Protection/support/attaches vessel to surrounding tissue/stretchytissue/stretchy

Why does it make sense that veins hold more blood in your circulatory system compared to arteries?

Arteries vs. VeinsArteries vs. Veins ArteriesArteries

Carry blood away from Carry blood away from heartheart

More smooth muscleMore smooth muscle Smaller lumen due to Smaller lumen due to

more musclemore muscle A lot of pressureA lot of pressure No valvesNo valves

VeinsVeins Return blood to heartReturn blood to heart Little smooth muscleLittle smooth muscle Bigger lumen due to Bigger lumen due to

less muscleless muscle Low pressureLow pressure ValvesValves

Veins are under low pressure due to bigger lumen; difficult for blood to get back to the heart from the feet – need help:

Skeletal muscle surrounds veins and helps push blood back to heart

Pressure in chest from breathing (inhaling)

Valves (semilunar valves) prevent backflow (exhaling)

CapillariesCapillaries

Smallest blood vesselsSmallest blood vessels One layer of epithelial tissue for easy One layer of epithelial tissue for easy

diffusion of nutrients, electrolytes, diffusion of nutrients, electrolytes, gas and wastegas and waste

No muscleNo muscle Connect the smallest arterioles and Connect the smallest arterioles and

venules.venules.

Heart AnatomyHeart Anatomy

Membranes (layers) of the Membranes (layers) of the HeartHeart

PericardiumPericardium – protects heart and anchors it to – protects heart and anchors it to sternum and diaphragmsternum and diaphragm serous membrane – double layered membrane; serous membrane – double layered membrane;

secretes serous fluid to separate layer lining cavity secretes serous fluid to separate layer lining cavity ((parietalparietal) and layer covering the organ () and layer covering the organ (visceralvisceral); ); prevents friction and rubbing and provides a prevents friction and rubbing and provides a slippery surface for the movements of the heart.slippery surface for the movements of the heart.

Visceral pericardium also called EpicardiumVisceral pericardium also called Epicardium – – deepest layer of pericardium that covers the heartdeepest layer of pericardium that covers the heart

MyocardiumMyocardium – cardiac muscle interwoven with – cardiac muscle interwoven with dense fibrous connective tissuedense fibrous connective tissue

EndocardiumEndocardium – sheet of epithelium – sheet of epithelium surrounding the open cavities; prevents leaks surrounding the open cavities; prevents leaks (has some connective tissue underlying it)(has some connective tissue underlying it)

Membranes (layers) of the Membranes (layers) of the HeartHeart

Heart Parts ContinuedHeart Parts ContinuedChambersChambers AtriaAtria – two cavities on top – – two cavities on top –

right receives deoxygenated right receives deoxygenated blood from body, left blood from body, left receives oxygenated blood receives oxygenated blood from the lungsfrom the lungs

VentriclesVentricles – the inferior and – the inferior and larger cavities – right pumps larger cavities – right pumps blood to the lungs, left blood to the lungs, left pumps blood to the rest of pumps blood to the rest of body (*bigger ventricle and body (*bigger ventricle and muscle is thicker as a result)muscle is thicker as a result)

SeptumSeptum – divides the heart – divides the heart into right and leftinto right and left

What is the advantage of a fourchambered heart?

Heart ValvesHeart Valves Atrioventricular Valves Atrioventricular Valves

(AV valves) (AV valves) (look like (look like saloon doors)saloon doors) Between the atria and Between the atria and

ventriclesventricles Allows for movement of blood Allows for movement of blood

from atria to ventriclesfrom atria to ventricles As the ventricles contract it As the ventricles contract it

forces the flap of the valve to forces the flap of the valve to close and then opens during close and then opens during ventricular relaxationventricular relaxation

Left valve = Left valve = bicuspidbicuspid (2 flaps) (2 flaps) or or mitral valvemitral valve

Right valve = Right valve = tricuspidtricuspid (3 (3 flaps)flaps)

Heart ValvesHeart Valves Semilunars – pulmonary Semilunars – pulmonary

and aortic and aortic (look like half (look like half moons)moons) Cover the pulmonary Cover the pulmonary

and aortic arteriesand aortic arteries Open up into the arteryOpen up into the artery Open when the Open when the

ventricles are ventricles are contracting so that blood contracting so that blood can exit to the body or can exit to the body or lungslungs

Back flow closes them so Back flow closes them so that blood doesn’t flow that blood doesn’t flow back into the heartback into the heart

Path of Blood Through the HeartPath of Blood Through the Heartblood enters R blood enters R lungs, enters L lungs, enters L body body

Part 1: fill blood with O2, Part 2: deliver O2 rich blood to Part 1: fill blood with O2, Part 2: deliver O2 rich blood to bodybody

Path of Blood Through the Path of Blood Through the HeartHeart

blood enters R blood enters R lungs, enters L lungs, enters L body bodyPart One: fill blood with O2, Part Two: deliver O2 rich blood to Part One: fill blood with O2, Part Two: deliver O2 rich blood to

bodybody1.1. Rt. Atrium receives oxygen poor blood returning Rt. Atrium receives oxygen poor blood returning from the body through the vena cava (superior from the body through the vena cava (superior and inferior).and inferior).

2.2. Blood flows to the rt. Ventrical through the right Blood flows to the rt. Ventrical through the right AV valve (tricuspid)AV valve (tricuspid)

3.3. Rt. Ventricle pumps blood to lungs through Rt. Ventricle pumps blood to lungs through pulmonary semilunar valve into the pulmonary pulmonary semilunar valve into the pulmonary arteries.arteries.

4.4. Oxygenated blood from the lungs returns to the Oxygenated blood from the lungs returns to the heart through the pulmonary veins into the left heart through the pulmonary veins into the left atrium atrium

5.5. Blood flows to left ventricle through left AV valve Blood flows to left ventricle through left AV valve (bicuspid or mitral valve) and is pumped out to (bicuspid or mitral valve) and is pumped out to body through the aorta through the aortic body through the aorta through the aortic semilunar valve.semilunar valve.*Blood circulates to the heart thru coronary arteries - only *Blood circulates to the heart thru coronary arteries - only when it is relaxedwhen it is relaxed

VIDEO

Cardiac CycleCardiac Cycle Describes all the activities of the heart Describes all the activities of the heart

through one complete heartbeatthrough one complete heartbeat one contraction and relaxation of both the atria one contraction and relaxation of both the atria

and ventricles.and ventricles. Systole “pumping”Systole “pumping” - a - a contractioncontraction event (of event (of

either the atria or ventricles) – blood exits the either the atria or ventricles) – blood exits the chamberchamber

Diastole “filling”Diastole “filling” - a - a relaxationrelaxation event (of event (of either the atria or ventricles) - blood enters either the atria or ventricles) - blood enters the chamberthe chamber

Review of the Heart

Diastole = relaxation

Systole = contraction

Note: Both SL valveswork together and both AV valves work Together (open andclose together)

And, they work oppositeof each other. If SL are open, AV are closedAnd vice versa.

Cardiac Cycle

Cardiac Cycle StepsCardiac Cycle Steps1. 1. Relaxing heart (atrial and ventricular Relaxing heart (atrial and ventricular

diastole ) diastole ) - AV valves open/ SL valves closed- AV valves open/ SL valves closed

2. Atrial systole (ventricles still in diastole) – 2. Atrial systole (ventricles still in diastole) – pushes any blood still in atria to ventricles pushes any blood still in atria to ventricles before they contractbefore they contract- Valves are the same- Valves are the same

3. Ventricular systole (atria are relaxing – 3. Ventricular systole (atria are relaxing – already contracted)already contracted)- AV valves close so blood doesn’t squirt - AV valves close so blood doesn’t squirt back into the atria, SL open to let blood go back into the atria, SL open to let blood go to lungs and the bodyto lungs and the body

Heart SoundsHeart Sounds ““lubb-dupp,” lubb-dupp,” - blood turbulence generated by the - blood turbulence generated by the

closing of the AV valves and then the semilunar closing of the AV valves and then the semilunar valvesvalves

11stst sound sound: AVs slam shut when ventricles contract: AVs slam shut when ventricles contract Louder because blood is pushing out of the Louder because blood is pushing out of the

ventricals and ventricals and slams the AVs closedslams the AVs closed 22ndnd sound sound: Semilunars shut when ventricles relax: Semilunars shut when ventricles relax

Softer sound – due to back flow of blood Softer sound – due to back flow of blood closing the closing the semilunarssemilunars

Abnormal heart sounds (murmurs) are usually caused Abnormal heart sounds (murmurs) are usually caused by improperly functioning valves. by improperly functioning valves.

PulsePulse Your pulse is the rhythmic expansion of the arteries as blood Your pulse is the rhythmic expansion of the arteries as blood

spurts from the left ventricle.spurts from the left ventricle. Therefore, your Therefore, your pulsepulse is also called your is also called your heart rate heart rate - number of - number of

times your heart beats each minute (times your heart beats each minute (bpmbpm).). Counting your pulse rate is a simple way to find out how fast your Counting your pulse rate is a simple way to find out how fast your

heart is beatingheart is beating You check your pulse rate by counting the beats in a set period of You check your pulse rate by counting the beats in a set period of

time (at least 15 to 20 seconds) and multiplying that number to time (at least 15 to 20 seconds) and multiplying that number to get the number of beats per minute. get the number of beats per minute.

Your pulse changes from minute to minute. It will be faster when Your pulse changes from minute to minute. It will be faster when you exercise, have a fever, or are under stress. It will be slower you exercise, have a fever, or are under stress. It will be slower when resting and healthy.when resting and healthy.

Typically use your carotid arteries in your neck or radial artery in Typically use your carotid arteries in your neck or radial artery in your wrist.your wrist.

Blood PressureBlood Pressure Force blood exerts against inner walls of Force blood exerts against inner walls of

blood vessels (systemic arteries – arteries blood vessels (systemic arteries – arteries supplied by branches of aorta with oxygen rich supplied by branches of aorta with oxygen rich blood being sent to the body)blood being sent to the body)

Determined by blood volume and diameter of Determined by blood volume and diameter of blood vessels.blood vessels. Importance? – To circulate blood against gravityImportance? – To circulate blood against gravity

Too high leads to tearing of inner epithelial wall, too Too high leads to tearing of inner epithelial wall, too low then can’t circulate blood (O2, nutrients, etc.)low then can’t circulate blood (O2, nutrients, etc.)

Usually measure the pressure in the brachial Usually measure the pressure in the brachial arteryartery

Blood PressureBlood Pressure Average bp in healthy young adults ranges from 110-Average bp in healthy young adults ranges from 110-

140/75-80140/75-80 Top # is the systolic pressure, bottom # is the diastolic Top # is the systolic pressure, bottom # is the diastolic

pressurepressure Systolic blood pressure Systolic blood pressure - pressure measured in arteries of - pressure measured in arteries of

systemic circulation during ventricle contraction (systole) systemic circulation during ventricle contraction (systole) as blood exits the heart. as blood exits the heart.

Diastolic blood pressure Diastolic blood pressure – pressure measured in arteries – pressure measured in arteries of systemic circulation during ventricle relaxation of systemic circulation during ventricle relaxation (diastole) as blood returns to the heart.(diastole) as blood returns to the heart.

Why does it make sense that the systolic number is Why does it make sense that the systolic number is higher (top number)higher (top number)

Pressure Reduces In SystemPressure Reduces In SystemArteries to VeinsArteries to Veins

As blood travels through the arterial As blood travels through the arterial system, b.p. drops sharply in the system, b.p. drops sharply in the arterioles and falls to between 40 arterioles and falls to between 40 and 20 mm Hg in the capillaries. and 20 mm Hg in the capillaries. Blood pressure descends further in Blood pressure descends further in the venules and veins. the venules and veins.

What controls resistance in What controls resistance in blood vessels? In other words, blood vessels? In other words, what causes bp to inc and dec?what causes bp to inc and dec?

Kidneys monitor blood volume – if too high - Kidneys monitor blood volume – if too high - ↑ water ↑ water output – if too low – retain salt which causes water retentionoutput – if too low – retain salt which causes water retention

Blood vessel constriction (inc bp)/dilation (dec bp)Blood vessel constriction (inc bp)/dilation (dec bp) Cold – bv constrictionCold – bv constriction Fight or flight – stress hormones cause vasoconstriction Fight or flight – stress hormones cause vasoconstriction

except to skeletal muscleexcept to skeletal muscle If lose blood – vasoconstriction to combat pressure lossIf lose blood – vasoconstriction to combat pressure loss When stand up – pressure drops since it is hard to return When stand up – pressure drops since it is hard to return

blood to the heart against gravity – pressure receptors blood to the heart against gravity – pressure receptors signal brain to cause vasoconstriction and increase heart signal brain to cause vasoconstriction and increase heart rate so blood pressure is maintainedrate so blood pressure is maintained

Alcohol lowers bpAlcohol lowers bp Nicotine and caffeine raises bpNicotine and caffeine raises bp

Cardiovascular Disease (CVD)Cardiovascular Disease (CVD) HypertentionHypertention (high bp) – sustained b.p. of (high bp) – sustained b.p. of

140/90 and above – damages epithelial lining 140/90 and above – damages epithelial lining and accelerates atherosclerosisand accelerates atherosclerosis

AtherosclerosisAtherosclerosis (hardening of arteries) – build (hardening of arteries) – build up of plaque in arteries up of plaque in arteries leads to heart leads to heart attack or attack or strokestroke (reduced blood supply to the (reduced blood supply to the brain). Ex: coronary heart attackbrain). Ex: coronary heart attack

Congenital disorder Congenital disorder – born with– born with

Electricity Thru the HeartElectricity Thru the Heart1.1. SA (sinoatrial node – pacemaker) SA (sinoatrial node – pacemaker) gets gets

the signal from the brain and sends the the signal from the brain and sends the electrical impulse through the atria to electrical impulse through the atria to the the AV (atrioventricular) nodeAV (atrioventricular) node. The atria . The atria then contract.then contract.

2.2. AV node delays the impulse – allows atria AV node delays the impulse – allows atria to finish contractingto finish contracting

3.3. AV node AV node sends the pulse down the sends the pulse down the AV AV bundle bundle to the bundle branches to the to the bundle branches to the Purkinje fibers Purkinje fibers in the walls of the in the walls of the ventriclesventricles

4.4. Heart contracts from the apex up Heart contracts from the apex up sending blood up and out thru the aorta sending blood up and out thru the aorta or pulmonary trunkor pulmonary trunk

Echocardiogram (EKG or Echocardiogram (EKG or ECG)ECG)

Measurement of the electrical wave Measurement of the electrical wave (electrical signal passing through the (electrical signal passing through the heart) that sets off muscle contractionheart) that sets off muscle contraction

Purpose: determine abnormalities in Purpose: determine abnormalities in heart muscle.heart muscle. Can determine heart rate too but Can determine heart rate too but

unnecessary; can determine through unnecessary; can determine through

pulsepulse

How to Read an EKGHow to Read an EKG

P-wave – preceeds the contraction of the atria

Atria are depolarizing (Na+ is flowing into T-tubules)

QRS wave – preceeds ventricular contraction – Ventricles are depolarizingT wave – the ventricles repolarizing – returning Na+ and K+ to normal

Can’t see the atria repolarizing since it is behind the QRS wave

Can tell if heart beats too fast or slow if heart is abnormally large due to overwork by size of waves

tachycardiatachycardia

(Fast heart rate)

(slow heart rate)

Cat: Left carotid artery branches fromthe brachiocephalic

Human: It branches directly from the aorta

Differences: Cat vs. HumanDifferences: Cat vs. Human

Cat: No common iliac artery; it immediately branches into external and internal iliacs

Human: Aorta branches into Common iliacs and then branch into internal and external iliacs