Surface Projection of the Heart

The Heart: Internal Anatomy

Four chambers

Atria

Receiving chambers Right atrium Left atrium

Ventricles

Discharging chambers Right ventricle Left ventricle

Heart valves

Allow blood to flow in one direction ONLY

Four valves

Atrioventricular Valves – between atria and ventricles

Bicuspid valve (left) Tricuspid valve (right)

Semilunar valves between ventricle and artery

Pulmonary semilunar valve Aortic semilunar valve

Layers of Heart Wall

Epicardium visceral layer of

serous pericardium

Myocardium cardiac muscle layer

is the bulk of the heart

Endocardium chamber lining &

valves

•Atria contract, blood fills ventricles through A-V valves

•Ventricles contract, blood pumped into aorta and pulmonary trunk through SL valves

Valve Function

Heart Murmur

Heart murmurs are most often caused by defective heart valves.

A valve may be unable to close completely.

This leads to regurgitation, which is blood leaking backward through the valve when it should be closed

Normal heartbeat murmur

Heart Sounds

Where to listen on chest wall for heart sounds.

What Causes the Heartbeat?

Conduction System of Heart

Cardiac Cells Cells fire spontaneously, act as pacemaker and form conduction system

for the heart Sino-atrial node

cluster of cells in wall of Rt. Atria begins heart activity that spreads to both atria excitation spreads to AV node

Atrial-Ventricular node in atrial septum,

transmits signal to Bundle of His

Bundle of His (HI-SS) the connection

between atria & ventricles

divides into bundle branches & purkinje fibers, large diameter fibers that conduct signals quickly

Rhythm of Conduction System

SA node fires spontaneously 90-100 times per minute

AV node fires at 40-50 times per minute

Artificial pacemaker needed if pace is too slow

Extra beats forming at other sites are called Ectopic Pacemakers caffeine & nicotine

increase activity

Physiology of Contraction

Depolarization, plateau, repolarization

Guess Who?

Each of you are will have a card taped on your

back.

You need to ask YES/NO questions ONLY

(2/person) to determine WHERE in the body you

are (head, trunk, arm, leg) form GROUPS

You can then ask YES/NO questions to determine

what you are within your group

Cardiac Cycle

Includes all events during blood flow from one heart

beat to the next

During this time, the pressure of the heart changes

Electrocardiogram---ECG or EKG

EKG Action potentials of all active cells can be detected and recorded

P wave atrial depolarization

P to Q interval conduction time from

atrial to ventricular excitation (SA to AV node)

QRS complex ventricular

depolarization

T wave ventricular repolarization

Garden Hose

Blood pressure

Definition: the force exerted against the inner walls

of blood vessels

Usually refers to the arteries branching off the

aorta

WHY?

• Measurements by health professionals are made on the pressure in large arteries

– Systolic – pressure at the peak of ventricular contraction (CONTRACTION OF HEART)

– Diastolic – pressure when ventricles relax (RELAXATION OF HEART)

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

Blood Pressure

Pulse

How do you feel your pulse?

Surge of blood into your system during ventricular

contraction

Pressure drops immediately, causing a recoil, which is

why you feel a pulse (the arterial walls recoil)

Factors affecting blood pressure

Cardiac Output = heart rate x stroke volume

Stroke volume = how much blood discharged from

ventricle with each contraction (~70 mL/average male)

Heart rate = beats per minute

Blood Volume ~5L/ average person

Ie. Hemorrhage, dehydration v. transfusion

Peripheral resistance: friction between

blood/vessel walls

Viscosity: ease at which molecules move past each

other

Blood Pressure

Normal Systolic Normal Diastolic

140-120 mm Hg 80-75 mm Hg

“120/80”

Variations in Blood Pressure

Human normal range is variable Normal BP

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

Hypotension Low systolic

(below 110 mm hg) Often associated

with illness

Hypertension High systolic

(above 140 mm hg) Can be dangerous if it is

chronic

Measuring Arterial Blood Pressure

Figure 11.18

Athletes

What do you think happens to their heart when you

exercise a lot?

Strong heart- pumps more blood during a single

beat

Hearts pump LESS during strenuous activity

Tend to have a LOWER resting heart rate

Practice

Imagine you are a particle stuck inside a human

body, specifically in the blood and circulating

You can write about your journey:

Blog post

Diary entry

Newspaper/Journalism article

Should discuss features from the heart (where blood

flows) and blood pressure (systolic, diastolic)!

Nervous System: Big Brother

Nervous system controls heartbeat

Sympathetic NS = fight or flight

Parasympathetic

NS = relaxation

What is your Resting

Heart Rate?

Normal = 60-75 Beats/Minute

THE BLOOD

The 3 Main Functions of Blood:

1. Transportation

2. Protection

3. Regulation

Blood is a connective tissue in liquid form

Greatest benefit from homeostasis: Continuous flow of

blood thru 60,000 miles of blood vessels

TRANSPORTATION:

Blood moves thru body where cells receive: Nutrients from digestive

organs Oxygen from lungs Hormones secreted from

endocrine gland

Cells give blood waste (CO2, urea & uric

acid) & their secretions

Protection:

From harmful microorganism & their toxins Through Phagocytic

white blood cells Specialized proteins

called Antibodies

Against fluid loss after an injury by clotting

Regulation: Regulates acid-base

balance of the body fluids By way of buffers Neutralize potential harmful

effects of: too much co2 acetic acid other compounds

Body temp. by cooling or heating parts of body

Controlled by Hypothalamus

Controls volume of blood flow to diff. areas of body

Figure

This figure highlights some of the major acute (short-term) effects

on the body during exercise.

Properties of Blood:

Color Volume pH

COLOR

RED COLOR = HEMOGLOBIN (PIGMENT

PROTEIN)

Arterial blood the O2 molecules are chemically bound to hemoglobin Crimson-red color

Venous blood O2 mol. are not as prevalent & blood= Dark red color w/a slightly bluish

tint

SEEN THROUGH SKIN VEINS LOOK GREENISH- BLUE but it is NOT GREEN OR BLUE

VOLUME

8% OF BODY WEIGHT Most in vessels--rest in

heart

Does not vary much from day to day or year to year

Avg. Male = 5-6 liters of blood

Avg. Female = 4-5 liters of blood

Difference due to avg body weight not sex

Apx. 8 pints

BLOOD

Formed Elements (45%)

Red Blood Cells

White Blood Cells

Platelets

Plasma (55%)

Water

Proteins

RED BLOOD CELLS (RBC)

Aka Erythrocytes

Biconcave disc: to transport gases

Puts hemoglobin closer to cell membrane

Protein which binds to oxygen

Gives cell its color

Oxyhemoglobin: bright red (when oxygen is bound)

Deoxyhemoglobin: dark red

45% of blood volume: known as hematocrit

(HCT)

WHITE BLOOD CELLS-WBC

Leukocytes

Less than 1% of total blood volume

5000 TO 10,000 in cubic mm

Any change in number… High or low indicates

a disease

Granulocytes

Cytoplasm contains highly visible pebble-like objects, known as granules

Twice the size of RBC’s

They contain a nucleus that is split into sections called lobes

Produced in red marrow

Three types: Eosinophils Neutrophils Basophils

Names come from the type of stain that brings out their distinguishing features Neutral Eosin Basic

Granulocytes

Neutrophil:

Most abundant = granulocyte

Stain pink in a neutral stain

Nucleus contains: 2 to 5 lobes Interconnected by thin bridges

Make up about 60% of all wbc’s in a normal blood sample

Phagocytizes small particles

Eosinophils:

1 to 4% of WBC’s in a normal blood sample

Granules stain red in an acid stain that contains a dye known as eosin

Nucleus = 2 lobes

Eosinophils are not: Very mobile

Or active

But can phagocytize certain foreign particles produced by allergic reactions Invading parasites Pollen grains Mold spores

Basophils:

Rarest0.5% or less of wbc’s in blood

Large granules that stain blue in basic stain

Nucleus is often bent into an s-shape with 2 lobes

Basophils & Mast cells produce a substance called = histamine causes swelling or

inflammation Swelling tells

other wbc’s where to find the site of infection

***Mast cells reside in tissues in the body,

and basophils are in the blood stream.

Agranulocytes:

Contain very small amount of cytoplasmic granules

2 types of cells

Monocytes

Lymphocytes

Both produced in red bone marrow

Also produced by organs of lymphatic system

Lymph nodes

Spleen

Thalamus

Monocyte:

Largest cells in blood

3x larger than rbc’s

2x larger than granulocytes

Nucleus can be round, oval, or lobed

Often occupies most of the cell volume

3 to 8% of wbc’s in a blood sample

Phagocytizes large

particles

Lymphocyte:

Same size as the rbc = the smallest wbc

Nucleus is round and large Takes up almost all of

cell volume

25-33% of wbc’s in a blood sample

Provides immunity

Function:

Protection from disease Move out of vessels =

diapedesis Once in the intestinal fluid

they act like ameba, extending streams of cytoplasmic arms called = pseudopodia

To find infection they sense chemicals released by invading microorganisms & damages cells http://video.search.yahoo.com/video/play?p=immune+respons

e&n=21&ei=utf-8&js=1&fr=yfp-t-501-s&fr2=tab-web&tnr=20&vid=2317323

Once found the wbc traps the microorganism and engulfs it = phagocytosis

The primary cells used for phagocytosis ar the neutrophils & monocytes

Neutrophils are mobile & usually arrive 1st at site of infection

Monocytes are very active too, large size allows for phagocytizing whole cells & large # of bacteria

When more wbc’s arrive at the site of infection they form a collection of living—dead—broken cells and plasma = pus

Not only phagocytosis to combat disease:

Highly specific proteins produced by the lymphocytes = Antibodies These act against

foreign particles and toxins that enter body

Production of antibodies = immunity

http://video.yahoo.com/watch/697741/3134456

Platelets:

Aka Thrombocytes Formed elements that

are fragments of complex cells

During development in red bone marrow, they are formed when a large precursor cell breaks apart

In small fragments platelets are released into blood stream for circulation

Larger fragments are broken down further to

form more platelets Each platelet contains:

Cytoplasm surrounded by a plasma membrane

No nucleus but most organelles found in cytoplasm

1/10 the size of a RBC

Shape = round or oval disk

150,000 to 360,000 platelets per cubic mm in normal blood sample = less numerous than rbc

Prevention of fluid loss Initiate the formation of blood clots

This plugs up the breaks in the blood vessel wall after an injury

Plasma

Clear, straw-colored liquid

92% water

Contains proteins which functions

are:

Maintaining blood pressure

Transporting lipids

Production of antibodies (type of)

Helps blood coagulate

BLOOD GROUPS

ABO & Rh

Cell Membrane

Blood grouping is based

on reaction between surface proteins (on RBC plasma proteins) & special plasma proteins

Agglutination = when cells clump together due to being different blood types

Death occurs due to destruction of RBC

Antigen = genetically determined proteins that are located on the surface of the plasma membrane of a rbc

Also called = Agglutinogen

Antibody

Antibody = protein within the plasma Also called = Agglutinins The rxn of an antigen & antibody determine if

blood will agglutinate or not

ABO System

Only 2 antigens in the ABO system A and B

You can have one, both or neither antigens on your rbc membrane A (one) B (one) AB (both) O (neither)

TYPE A ANTIGEN A ANTIBODY B

ANTI-B

TYPE B

ANTIGEN B

ANTIBODY A

ANTI-A

TYPE AB ANTIGEN A

ANTIGEN B

NO ANTIBODY

TYPE O NO ANTIGEN ANTIBODY A

ANTIBODY B

ANTI-A / ANTI-B

RBC PLASMA

BLOOD TYPE CAN DONATE

BLOOD TO

CAN RECEIVE

BLOOD FROM

A A

AB

A

O

B B

AB

B

O

AB AB A B

AB O

O A B

AB O

O

Blood Transfusions

If blood transfusion is unsuccessful then rbc’s die & hemoglobin are released into the body which can cause kidney failure & death!

If you match the wrong blood types agglutination will occur

Figure: Illustration Of The Forward And Reverse Grouping Reaction Patterns Of the ABO groups

Rh System

Named after rhesus monkey where it was 1st discovered

It was later found that the Rh antigen is on the RBC membrane of humans

If you have the Rh antigen you are: rh-positive.

If you don’t have the rh antigen you are: rh-negative.

Rh-negative MOTHER PREGNANT FOR THE 1ST TIME WITH Rh-positive FETUS

Rh antigens MAY DIFFUSE THRU PLACENTA TO MOTHERS BLOODSTREAM

OVER TIME MOTHER WILL DEVELOP anti-Rh antibodies IN RESPONSE

THE 1ST CHILD WILL BE BORN BEFORE BEING AFFECTED BY antibodies

A 2ND Rh-positive FETUS MAY RECEIVE anti-Rh antibodies FROM THE MOTHER

IF THIS OCCURS THE FETUS’S RBC WILL BE DESTROYED IF NOT CAUGHT BY DOCTORS

SENSITIZATION

If mothers anti-rh

antibodies cross the placenta to the 2nd fetus then agglutination will occur = Erythroblastosis Fetalis or Hemolytic Disease

The child will suffer from anemia & hypoxia (lack of o2) = brain damage or death Unless a blood transfusion

is performed before birth which will provide more rbc for o2 transport

If a 1st time pregnant woman knows she is rh-positive she can avoid sensitization by receiving medical treatment with rhogam

BLOOD VESSELS

Arteries

Carry blood away from the heart

Elastic Arteries: largest diameter, lots of

elastic tissue, little smooth muscle

Muscular Arteries: medium + small arteries,

both elastic and smooth muscle

Arterioles: transports blood from small arteries

to capillaries (40 micrometers to 9

micrometers)

What happens when your arteries

are blocked?

Atherosclerosis

Artery walls thicken because of fatty

acid/cholesterol build up

Coronary Stents

Video

http://www.youtube.com/watch?v=N7nghr9TpSU

Capillaries

Usually 7-9 micrometers in diameter

Usually 1 mm long!

Red blood cells flow in single file, and can be

folded

Networks are common in: (high metabolic)

Lungs

Liver

Kidneys

Skeletal muscle/cardiac

Veins

Venules: (up to 50 micrometers), similar to

capillaries

Small veins: (0.2-0.3 mm in diameter) smooth

muscle cells

Medium veins: most veins seen in dissection, collect

blood from small to deliver to large veins

Large veins: transport blood to the heart

Portal Veins: begin with capillary network, end with

secondary network (no pumping involved)

Valves

Veins >2mm have valves

Allow blood to flow TOWARD the heart, not in

the opposite direction

Two flaps that overlap so blood cannot flow in

the opposite direction

Medium veins have valves, # valves in lower

limbs > #valves upper limbs

Varicose Veins

Veins of lower limbs are stretched so that the valves

are incompetent

Blood flow goes backwards, can cause blood clots

Can result in phlebitis (inflammation of veins)

Can result in gangrene

Arterial Supply of the Brain

Figure 11.13

Carotid &

subclavian arteries supply head & neck w/blood

Carotid is the major supplier & branches into external & internal

Right subclavian artery originates from brachiocephalic artery

Left subclavian artery originates from aortic arch They branch into vertebral

arteries & thyrocervical arteries

Vertebral art. = Pass upward toward the foramina of the cervical vertebrae

Thyrocervical art. Extend short distance to tissues in neck which branch to supply:

Thyroid glands

Parathyroid

Larynx

Trachea

Esophagus

Pharynx

Muscles of head & neck

Figure Right subclavian arteriogram shows an aneurysm arising from the thyrocervical

trunk (arrow).

Systemic Veins

Large vessels that are formed by convergence of smaller veins & venules

Toward heart

Right atrium final destination

Superior & inferior vena cava

Some veins don’t go to inferior vena cava but toward liver

SUPERIOR MESENTERIC VEIN INFERIOR MESENTERIC VEIN

HEPATIC PORTAL VEINORIGINATE FROM DIGESTIVE TRACTHEPATIC PORTAL SYSTEM SHUTS BLOOD

FROM CAPILLARIES OF DIG. TRACT TO CAP. OF LIVER

LIVER

•Liver receives blood from 2 sources: •Hepatic Portal Vein •Hepatic Artery

•Blood that is high in O2 enters hepatic artery •Blood low in O2 enters hepatic portal vein

Venous blood from dig organs is low in O2 but still carries nutrients absorbed by intestines

Blood passes slowly thru capillaries in liver hepatic cells remove materials used for metabolic functions phagocytic cells eliminate bacteria etc that penetrate dig. lining

Blood passes thru liver cap collected by small veins that lead into hepatic veins emptied into inferior vena cava

Circulation to the Fetus

Blood Transport Routine Taking blood (Aorta)to the tissues and back (Vena Cavas)

– Arteries

– Arterioles

– Capillaries

– Venules

– Veins

Congestive Heart Failure

Causes of CHF coronary artery disease,

hypertension, MI, valve disorders, congenital defects

Left side heart failure less effective pump so more

blood remains in ventricle

heart is overstretched & even more blood remains

blood backs up into lungs as pulmonary edema

suffocation & lack of oxygen to the tissues

Right side failure fluid builds up in tissues as peripheral

edema

Clinical Problems

MI = Myocardial Infarction death of area of heart muscle

from lack of O2 replaced with scar tissue results depend on size

& location of damage

Blood Clot use clot dissolving

drugs streptokinase or t-PA & heparin

balloon angioplasty

Angina Pectoris heart pain from ischemia of

cardiac muscle

Myocardial Infarction

Myocardial infarction means heart attack, or coronary thrombus.

Infarction = death of muscle, tissue or organ as a result of a blockage of the blood supply

Blockage due to plaque buildup in arteries because of high cholesterol and saturated fats in diet

Bypass Surgery

By-Pass Graft Percutaneous Transluminal Coronary

Angioplasty

Stent in an Artery

Maintains patency of blood vessel

What's an Artificial Pacemaker? •“Artificial pacemaker" is a small, battery-operated device that helps the heart beat in a regular rhythm by sending electrical impulses to the heart to help it pump properly •An electrode is placed next to the heart wall and small electrical charges travel through the wire to the heart. •Most pacemakers are demand pacemakers. •They have a sensing device •It turns the signal off when the heartbeat is above a certain level •It turns the signal back on when the heartbeat is too slow.

• As the blood is pumped back to the heart, veins act as one-way valves to prevent the blood from flowing backwards.

• If the one-way valve becomes weak, some of the blood can leak back into the vein, collect there, and then become congested or clogged.

•This congestion will cause the vein to abnormally enlarge. These enlarged veins can be either vericose or spider veins.

•Lack of oxygen in the blood causes a bluish discoloration in the skin or mucous membranes called cyanosis.

•Most cyanosis is seen as a result of congenital heart disease, pulmonary disease, or as a terminal event as in cardiopulmonary arrest.

Desirable Levels of Blood Cholesterol for Adults

TC (total cholesterol) under 200 mg/dl

LDL under 130 mg/dl HDL over 40 mg/dl Normally,

triglycerides are in the range of 10-190 mg/dl.

Among the therapies used to reduce blood cholesterol level are exercise, diet, and drugs.

Exercise and the Heart

Sustained exercise increases oxygen demand in muscles.

Benefits of aerobic exercise (any activity that works large body muscles for at least 20 minutes, preferably 3-5 times per week) are; increased cardiac output increased HDL and decreased

triglycerides improved lung function decreased blood pressure weight control.