Chapter 12Chapter 12

Human Anatomy & Human Anatomy & PhysiologyPhysiology

The The Cardiovascular Cardiovascular

SystemSystem

I. Overview of the I. Overview of the Cardiovascular SystemCardiovascular System

The The circulatory systemcirculatory system can be thought can be thought of as the of as the transport system of the bodytransport system of the body. .

A closed system consisting of the heart, blood vessels, and blood– The heart pumps blood– Blood vessels allow blood to circulate to all

parts of the body FunctionFunction: : Deliver oxygen & nutrient-Deliver oxygen & nutrient-

rich blood to body cells and remove rich blood to body cells and remove carbon dioxide and wastecarbon dioxide and waste

A. Overview of the HeartA. Overview of the Heart

The heart is located in the The heart is located in the thoracic thoracic cavity between the lungs slightly to cavity between the lungs slightly to the leftthe left

A hollow, cone-shaped A hollow, cone-shaped musclemuscle about about the the size of a size of a fistfist

Made up of Made up of cardiac musclecardiac muscle

II. Anatomy of the HeartII. Anatomy of the Heart1. Coverings: Pericardium – a

double serous membrane– Visceral pericardium

(epicardium) Next to heart

– Parietal pericardium Outside layer

Serous fluid fills the space between the layers of pericardium

2. Heart Walls: Three layers

a] Epicardium– Outside layer– This layer is the visceral pericardium

b] Myocardium– Middle and thickest layer– Mostly cardiac muscle

c] Endocardium– Inner layer– Made up of simple squamous epithelium

3. Chambers3. Chambers The heart has 4

chambers– Left & right atria –

receive blood– Left & right

ventricles -pump blood out

Chambers are separated by a septum

4. Heart Valves4. Heart Valves Valves are are flaps of connective tissueflaps of connective tissue

between the atria and ventriclesbetween the atria and ventricles Moves the blood through the heart in Moves the blood through the heart in

one directionone direction Valves open as blood is pumped

through Held in place by chordae tendineae

(“heart strings”) Valves are closed to prevent backflow

Four valves a. Atrioventricular valves – between atria and ventricles, open valves– left atrium left atrium bicuspid valvebicuspid valve left ventricle left ventricle– right atria right atria tricuspid valvetricuspid valve right right

ventricleventricle

b. Semilunar valves - between ventricle and artery, closed valves– right ventricle right ventricle pulmonary semilunar pulmonary semilunar

valvevalve pulmonary artery pulmonary artery– left ventricle left ventricle aortic valveaortic valve aorta aorta

5. Major Vessels5. Major Vessels Aorta

– Blood leaves left ventricle towards body

Pulmonary arteries– Oxygen-poor blood

leaves right ventricle towards lung

Vena cava– Superior and inferior– Blood from the body

enters the right atrium

Pulmonary veins (4)– Oxygen-rich blood

from lungs enters left atrium

Blood VesselsBlood Vessels are tubes which are tubes which transport bloodtransport blood

A. Function:A. Function:– Transport bloodTransport blood– Carry out the exchange of gases and Carry out the exchange of gases and

wastewaste– Regulate blood pressureRegulate blood pressure– Direct blood flowDirect blood flow

IV. Anatomy of Blood IV. Anatomy of Blood VesselsVessels

B. Types of Blood B. Types of Blood VesselsVessels

1. Arteries1. Arteries Blood vessels Blood vessels

which carry which carry oxygen-rich blood oxygen-rich blood away from the away from the heart to the body. heart to the body.

The aorta is the The aorta is the largest artery in largest artery in our bodyour body

Thick wallsThick walls

2.2. CapillariesCapillaries Microscopic blood vessels which Microscopic blood vessels which

connect arteries and veins togetherconnect arteries and veins together Where Where exchangeexchange of oxygen, carbon of oxygen, carbon

dioxide, nutrients, and waste occur dioxide, nutrients, and waste occur One cell layer thickOne cell layer thick

3. Veins3. Veins Blood vessels which Blood vessels which

carry oxygen-poor carry oxygen-poor bloodblood from the body from the body back back to the heartto the heart..

Thin walls Thin walls Requires muscles to Requires muscles to

push blood back to push blood back to the heartthe heart

C. DiseasesC. Diseases 1. 1. ArteriosclerosisArteriosclerosis

– The hardening of the arteries due to the The hardening of the arteries due to the formation of scar tissueformation of scar tissue

– Leads to hypertension, heart attack, & Leads to hypertension, heart attack, & strokestroke

2. 2. Varicose veinsVaricose veins– Valves in the veins become weak leading to Valves in the veins become weak leading to

abnormal dilations in the superficial veinsabnormal dilations in the superficial veins 3. 3. PhlebitisPhlebitis

– Inflammation of a vein Inflammation of a vein – Very serious because it can lead to Very serious because it can lead to

thromboembolism and deaththromboembolism and death

IV. Circulation of Blood IV. Circulation of Blood in the Bodyin the Body

Circulation is the transportation Circulation is the transportation of bloodof blood

A. The goal is to 1. Send oxygen-poor blood to the the

lungs to pick up oxygen and then 2. To pump oxygen-rich blood from

the heart to the body cells

B. Three circulation pathways1. Pulmonary

circulation From heart to lungs

2. Systemic circulation

From heart to body

3. Coronary circulation

From heart to heart muscle

C. Pulmonary CirculationC. Pulmonary Circulation1. Flow of blood from the heart to the lungs DEOXYGENATED BLOOD must have carbon dioxide DEOXYGENATED BLOOD must have carbon dioxide

removed, so it is sent to the lungsremoved, so it is sent to the lungs– Body cells >Body cells >– Veins >Veins >– Vena cava (1)>Vena cava (1)>– R Atrium (2)>R Atrium (2)>– Tricuspid valve >Tricuspid valve >– R Ventricle >R Ventricle >– Pulmonary Semilunar valve>Pulmonary Semilunar valve>– Pulmonary ARTERY (3) >Pulmonary ARTERY (3) >– LungsLungs

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D. Systemic CirculationD. Systemic Circulation1. Flow of blood from the heart to the body OXYGENATED BLOOD coming back from the lungs is pumped to OXYGENATED BLOOD coming back from the lungs is pumped to

the body cellsthe body cells

– Lungs >Lungs >– Pulmonary VEINS (4)>Pulmonary VEINS (4)>– L Atrium >L Atrium >– Bicuspid (mitral) valve >Bicuspid (mitral) valve >– L Ventricle (5) >L Ventricle (5) >– Aortic Valve >Aortic Valve >– Aorta (6)>Aorta (6)>– Arteries >Arteries >– Body cellsBody cells

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Happy Days: Pump your Happy Days: Pump your bloodblood

http://www.youtube.com/watch?v=upctPUa6RhA

C. Coronary CirculationC. Coronary Circulation1. Flow of blood to the heart tissues The heart has its own nourishing circulatory

system– Coronary arteries – from aorta to myocardium

(heart muscle)– Cardiac veins – from the myocardium to the

ventricle

2. Coronary disorders2. Coronary disorders

a. Atherosclerosisa. Atherosclerosis – blockage of the – blockage of the arterial walls due to the build up of arterial walls due to the build up of cholesterol that can lead to a heart cholesterol that can lead to a heart attackattack

b. Thromboembolismb. Thromboembolism – blood clot – blood clot that breaks away from its origin and that breaks away from its origin and is carried to a new location is carried to a new location

Can lead to a heart attack if embolus blocks Can lead to a heart attack if embolus blocks a coronary arterya coronary artery

Comparison of Arteries Comparison of Arteries

3. Prevention & 3. Prevention & TreatmentTreatmenta. Aspirin – reduces stickiness of platelets, therefore prevents clotsb. Surgery – i. Balloon Angioplasty – tube

is guided through the blood vessel to the blockage where is inflated to open up the vessel or break the clot

– ii. Coronary Bypass Operation – a blood vessel from another part of the body is sutured from the aorta to the coronary artery, past the blocked area

– Allows blood to flow to cardiac muscle

VideosVideos

Balloon AngioplastyBalloon Angioplasty– http://www.youtube.com/watch?v=F_gV

BK6YkPA

Coronary BypassCoronary Bypass– http://www.youtube.com/watch?v=8nbs

cVKKSm8

V. BloodV. Blood The only fluid tissue in the human

body Taste, odor, 5x thicker than water Color range

– Oxygen-rich blood is scarlet red– Oxygen-poor blood is dull red

pH must remain between 7.35–7.45 5-6 Liters or about 6 quarts/body

A. CompositionA. Composition

1. Blood Plasma Makes up 55% of blood Composed of 90% of water Contains nutrients, salts (metal ions),

respiratory gases, hormones, proteins, waste products

2. 2. Erythrocytes – Red Erythrocytes – Red Blood CellsBlood Cells

The main function is to carry oxygen

Biconcave disks Anucleate (no nucleus) Outnumber white blood

cells 1000:1 Each erythrocyte has

250 million hemoglobin molecules– Iron-containing protein– Binds strongly to oxygen

3. 3. Leukocytes – White Blood CellsLeukocytes – White Blood Cells Crucial in the body’s defense against disease

4. 4. PlateletsPlatelets Small fragments

produced from ruptured cells (megakaryocytes)

Needed for the clotting process

B. Blood DisordersB. Blood Disorders 1. Anemia1. Anemia – caused – caused

by low iron or by low iron or hemoglobin hemoglobin – Symptoms: fatigue, Symptoms: fatigue,

dizziness, dizziness, headaches, short headaches, short of breathof breath

2. Sickle cell Anemia 2. Sickle cell Anemia – recessive genetic – recessive genetic disorder disorder – Symptoms: fatigue, Symptoms: fatigue,

bone pain, ulcers, bone pain, ulcers, delayed growth, delayed growth, short of breathshort of breath

3. Hemophilia 3. Hemophilia – – recessive sex-linked recessive sex-linked bleeding disorderbleeding disorder– Blood lacks clotting Blood lacks clotting

factorsfactors– Minor injuries can Minor injuries can

cause uncontrolled cause uncontrolled bleedingbleeding

VI. Physiology of the VI. Physiology of the HeartHeart

A. Conduction System of the HeartA. Conduction System of the Heart Initiates, stimulates, and coordinates Initiates, stimulates, and coordinates

the contraction of the atria and the contraction of the atria and ventriclesventricles– Makes the heart an effective pumpMakes the heart an effective pump

2 types of Nodal tissue controls the 2 types of Nodal tissue controls the heartbeatheartbeat– SA (sinoatrial) NodeSA (sinoatrial) Node – found in right atrium – found in right atrium

Initiates the heartbeat every 0.85 secondsInitiates the heartbeat every 0.85 seconds Serves as the Serves as the pacemakerpacemaker

– AV (atrioventricular) NodeAV (atrioventricular) Node – bottom of right – bottom of right atriumatrium

The SA node sends out an

impulse causing the

atria to contract.

The impulse reaches the

AV node and travels along

the AV bundle.

The impulses travels

throughout the ventricles

to the Purkinje fibers.

Ventricles

contract.

B. Cardiac Cycle & Heart B. Cardiac Cycle & Heart SoundsSounds

Cardiac cycle includes all the events Cardiac cycle includes all the events that occur in one heartbeatthat occur in one heartbeat– Heart beats ~70x/minuteHeart beats ~70x/minute

L & R atria contract simultaneouslyL & R atria contract simultaneously Atria relaxes then L & R ventricles Atria relaxes then L & R ventricles

contract simultaneouslycontract simultaneously Systole – contraction Diastole - relaxation

1. Atrial systole – 0.15 sec1. Atrial systole – 0.15 sec– Atria is systole (contracted) pumping Atria is systole (contracted) pumping blood into blood into

ventriclesventricles (diastole-relaxed) (diastole-relaxed) 2. 2. Ventricle SystoleVentricle Systole - 0.30 sec - 0.30 sec

– Ventricle fills with blood and contracts pumping Ventricle fills with blood and contracts pumping blood to the aorta and pulmonary arteriesblood to the aorta and pulmonary arteries

3. 3. Atrial & Ventricle DiastoleAtrial & Ventricle Diastole – 0.40 sec – 0.40 sec– Both atria & ventricles are diastole (relaxed) as Both atria & ventricles are diastole (relaxed) as

blood from the body fills the atriablood from the body fills the atria

What is that What is that sound?sound?

- - LupLup: closing : closing of the bicuspid of the bicuspid and tricuspid and tricuspid valvevalve

- - DupDup: closing : closing of aortic and of aortic and pulmonary pulmonary valvevalve

Bicuspid

Valve

C. Measuring the Cardiac CycleC. Measuring the Cardiac Cycle Electrocardiograms (EKG or ECG) Electrocardiograms (EKG or ECG)

are used to measure the are used to measure the electrical rhythm of the heart’s electrical rhythm of the heart’s contractioncontraction

PQRST WaveformPQRST Waveform

D. DisordersD. Disorders Damage to AV node = muscles cells Damage to AV node = muscles cells

in the ventricles do not beat together in the ventricles do not beat together results in a slower heart beatresults in a slower heart beat– Slower heart beat can lead to fibrillationSlower heart beat can lead to fibrillation

Fibrillation = lack of blood flow to the heartArrhythmia = irregular heart beat

Tachycardia = more than 100 beats/minBradychardia = less than 60 beats/min

PacemakerPacemaker

Used to maintain a Used to maintain a consistent heart consistent heart rate when the rate when the body’s natural body’s natural pacemaker (SA pacemaker (SA node) is not node) is not properly properly functioningfunctioning

C. Vital SignsC. Vital Signs1. 1. PulsePulse The The stretching stretching

and recoiling of and recoiling of the arterial the arterial wallwall as blood as blood surges throughsurges through

Monitored at “pressure points” where pulse is easily palpated

2. Blood Pressure2. Blood Pressure A device called a sphygmomanometer

measures the pressure in large arteries – Systolic: pressure at the peak of ventricular

contraction– Diastolic: pressure when ventricles relax

Pressure in blood vessels decreases as the distance away from the heart increases

http://blood-pressure.emedtv.com/high-blood-pressure-video/what-is-blood-pressure-video.html

Measuring blood pressureMeasuring blood pressure

Variations in blood pressure– Normal

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

– Hypotension (Low BP) Low systolic (below 110 mm HG) Often associated with illness

– Hypertension (High BP) High systolic (above 140 mm HG) Can be dangerous if it is chronic Warning sign for stroke and heart

attack risk

HypertensionHypertension

Effects of High Blood Effects of High Blood PressurePressure

http://www.youtube.com/watch?http://www.youtube.com/watch?v=pPxnIh_WTb8&feature=relatedv=pPxnIh_WTb8&feature=related

http://blood-pressure.emedtv.com/http://blood-pressure.emedtv.com/high-blood-pressure-video/what-is-high-blood-pressure-video/what-is-blood-pressure-video.htmlblood-pressure-video.html