Tainted Love

Introduction Function:

– Transport materials around body Components:

– Heart– Blood Vessels

The Heart Layers in Cross Section:

– Pericardium- outermost sac enclosing heart

– Pericardial Fluid- fluid between pericardium and epicardium

– Epicardium- tight fitting layer surrounding heart; also called visceral pericardium

– Myocardium- cardiac muscle layer– Endocardium- smooth inner layer of

heart

Heart Structure Four chambers:

– Right and left atria- receive blood into heart

– Right and left ventricle- pump blood back out of the heart

Two sides are separated by septum

Valves Four Valves in Heart:

1.Tricuspid - between right atrium and right ventricle

2.Pulmonary Semilunar - between right ventricle and pulmonary trunk

3.Mitral (Bicuspid) - between left atrium and left ventricle

4.Aortic semilunar - between left ventricle and aorta

Two Circulations of Blood Pulmonary:

– Back and forth to lungs Systemic:

– Back and forth to body

Path of Blood Through Heart

Exit Slip 1) What chamber is this? 2) Which valve is between

right atrium and right ventricle? 3) Which circuit (pulmonary or

systemic) brings blood back and forth to lungs?

1) Right atrium 2) Tricuspid 3) Pulmonary

Internal Heart

Identification

Vessels Supplying the Heart Coronary arteries

– First two branches off of the aorta

– Supply blood to heart Cardiac veins

– Return blood from heart tissues

– Drain into coronary sinus Coronary sinus

– Returns blood back to right atrium

Cardiac Cycle Sequence of events that occur during

every regular heartbeat Systole - contraction Diastole - relaxation Refer to timeline

Systole/Diastole Song

THE FLOW OF BLOOD THROUGH THE HEART

 

Heart Sounds Lubb - sound of atrioventricular (AV)

valves closing Dupp - sound of semilunar valves

closing

Lubb, Dubb, …. Lubb, Dubb….

made by the closing of the heart valves.

"lub" made by the contraction of the ventricles and the closing of the atrioventricular valves.

“dupp" made by the semilunar valves closing.

Reminder about Cardiac Tissue Complex network of interconnecting

cells– Connected by intercalated discs– Allows them to transfer impulse rapidly

and work together (functional syncytium)

Two sets in heart: – One in atria, one in ventricles

Kept separate from each other

Cardiac Conduction Intro Electrical impulses cause heart

structures to contract Travel down a system of specialized

fibers

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QUICK REVIEW OF HEART Purpose Pumps blood Basic Anatomy 4 chambers 2 sides 4 valves

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THE CONDUCTINGY SYSTEM

SA Node Inter-nodal

pathway AV Node Bundle of HIS Bundle Branches Purkinje Fibers

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RELATIONSHIP

Why do we do an ECG? Measures:

– Any damage to the heart– How fast your heart is beating and whether it is

beating normally– The effects of drugs or devices used to control the

heart (such as a pacemaker)– The size and position of your heart chambers

Ordered if: – You have chest pain or palpitations (pounding/racing

heart)– You are scheduled for surgery– You have had heart problems in the past– You have a strong history of heart disease in the

family

Pathway for Conduction Sinoatrial node (SA node)

– Pacemaker– Causes atria to contract

Junctional Fibers – Delay impulse reaching ventricle by their

small diameter Atrioventricular node (AV node) Purkinje fibers

– Cause ventricles to contract

Electrocardiogram Also know as ECG Electrical recording

of myocardium during cardiac cycle

P wave– Atrial depolarization

QRS complex– Ventricle

depolarization and atrial repolarization

T wave– Ventricle

repolarization

Electrocardiogram (cont)

Each electrical signal begins in a group of cells called the sinus node or sinoatrial (SA) node. The SA node is located in the right atrium (AY-tree-um), which is the upper right chamber of the heart. (Your heart has two upper chambers and two lower chambers.)

In a healthy adult heart at rest, the SA node sends an electrical signal to begin a new heartbeat 60 to 100 times a minute.

From the SA node, the signal travels through the right and left atria. This causes the atria to contract, which helps move blood into the heart's lower chambers, the ventricles (VEN-trih-kuls). The electrical signal moving through the atria is recorded as the P wave on the EKG.

The electrical signal passes between the atria and ventricles through a group of cells called the atrioventricular (AV) node. The signal slows down as it passes through the AV node. This slowing allows the ventricles enough time to finish filling with blood. On the EKG, this part of the process is the flat line between the end of the P wave and the beginning of the Q wave.

The electrical signal then leaves the AV node and travels along a pathway called the bundle of His. From there, the signal travels into the right and left bundle branches. The signal spreads quickly across your heart's ventricles, causing them to contract and pump blood to your lungs and the rest of your body. This process is recorded as the QRS waves on the EKG.

The ventricles then recover their normal electrical state (shown as the T wave on the EKG). The muscle stops contracting to allow the heart to refill with blood. This entire process continues over and over with each new heartbeat.

Control of Heart Rate Cardiac Center of Medulla Oblongata

– Parasympathetic Constant braking action; acetylcholine

– Sympathetic Increases heart rate; norepinephrine

Blood Pressure Receptors– Decreases heart rate

Impulses from Cerebrum and Hypothalamus– Decrease heart rate

Changes in K and Ca concentrations

Thumbs Up, Down Coronary arteries supply blood to

heart.–UP!

The lubb of your heart is the sound of the AV closing/opening. –UP!

An ECG measures your blood pressure.–DOWN! It measures your cardiac

cycle.

Blood Vessels System of closed tubes filled with blood Arteries

– Carry blood away from heart Arterioles

– Smaller branches of arteries Capillaries

– Thin-walled vessels where nutrients, fluid, gases, and wastes are exchanged

Venules– Small veins

Veins– Large vessels returning blood to heart

Layers of Blood Vessel Walls Tunica externa

– Outermost layer composed of connective tissue with some elastic and collagenous fibers

Tunica media– Middle layer composed of smooth

muscle and elastic fibers Tunica interna (endothelium)

– Single layer of squamous epithelium

Control of Vessel Diameter Vasoconstriction– Sympathetic nervous system impulses cause

vessels to constrict Vasodialation

– Inhibition of impulse causes dialation

Arteries Carry blood away from heart under

high pressure Has the thickest tunica media and

tunica externa of all blood vessels

Arterioles Smaller branches of arteries Walls thin as the vessels get smaller Eventually lose tunic externa

Capillaries Site of exchange Only tunica interna

remains Has small openings

between endothelial cells where materials can leak out

Pre-capillary sphincters– Smooth muscle at start of

capillary that can close the capillary bed and divert blood flow

Exchange of Materials1. Oxygen and nutrients diffuse out of the

capillary2. Carbon dioxide and wastes diffuse back

into capillary3. Plasma Proteins don’t leave the blood4. Fluid is forced out of the capillary at the

arteriole side due to blood pressure5. Fluid is brought back into the capillary

due to osmotic pressure at the venule side

6. Fluid not recollected is brought back to the blood through the lymphatic system

Venules and Veins Venules

– Smaller veins Veins

– Large lumen– Thinner tunica media– Thinner tunica externa– Return blood to heart– Low pressure– Blood reservoir– Contains valves

Protect against backflow

Pumps your blood SON

G!

Heart Disorders Myocardial infarction (MI)

– Otherwise known as heart attack– Def: Blood clot obstructs a coronary

atery or one of its branches – killing part of the heart

– Causes: Diet (high in fat and/or salt)

– Causes build-up in plague (causes blood clot) Stress (usually from another illness)

– Symptoms: Pain in right arm, shortness of breath,

increased heart rate

Heart Disorders Atherosclerosis

– Def: arterial disease, hardening of arteries

– Very common– Causes:

Plague build-up (caused by diet high in fat)– Forms clots, blood has issues flowing through

Aging (older you get, more they harden) Heavy alcohol use Not exercising (EVER!) Obesity

– Can lead to heart attack or stroke

Heart Disorders Hypertension

– Def: High blood pressure Ex: 140/90 (normal – 120/80)

– Causes: Diet (high in fat and/or salt) Genetics (heart disease, diabetes) Stroke or heart attack Pregnancy/labor Kidney disease Race (African-Americans on average have

high BP) Gender

Heart Disorders Varicose veins

– Def: ruptured veins

– Causes: Abnormal

dilations– Caused by

increased blood pressure due to gravity

– Standing for abnormally long periods of time

Blood Pressure Force blood exerts on blood vessel

walls Highest in arteries; lowest in veins Max point:

– During ventricular systole; called systolic pressure

Min point: – Before next ventricular contraction;

called diastolic pressure Normal arteriole blood pressure:

120/80

Factors the Affect Blood Pressure Heart Action Blood Volume Peripheral

resistance Blood viscosity

Heart Action Stroke Volume

– Volume of blood discharged from the left ventricle during each contraction

Cardiac output– Volume of blood discharged from the left

ventricle/ minute– Cardiac Output=Stroke volume x Heart rate

(bpm) Cardiac output has proportional

relationship to blood pressure

Peripheral Resistance Blood moving against vessel walls

creates friction that impedes flow If vessels are constricted, blood

pressure raises If vessels are dilated, blood pressure

lowers

Blood Viscosity Viscosity

– Ease that a fluid flows– Increases when there are more formed

elements or plasma proteins– As viscosity increases so does blood

pressure

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Controlling Blood Pressure Cardiac Output

– Strength of ventricle contraction is controlled by amount of

– Baroreceptors- send messages to medulla oblongata about how to influence SA node

Peripheral resistance– Changes in blood pressure cause changes in

medulla oblongata’s Vein reservoir

– During exercise or venoconstriction more blood