Heart Blood Vessels

which work together to supply the body tissues with nourishment and collect waste materials.

The cardiovascular system carries blood and

dissolved substances to and from different places

in the body. The Heart has the job of pumping these things around the body. The Heart pumps blood and substances around the body in tubes called blood vessels.

The Heart and blood vessels together make up the

cardiovascular System.

What is the cardiovascular system?

Functions of the cardiovascular system:

Distribute nutrients,

Transport and exchange oxygen and carbon dioxide,

Remove waste materials,

Distribute secretions of endocrine glands,

Regulate body temperature.

lungs

head & arms

liver

digestive system

kidneys

legs

pulmonary artery

aorta

pulmonary vein

main vein

Left Right

How does this system work?

Cardiovascular System

Lungs

Body cells

Our cardiovascular system is a double circulatory system.

This means it has two parts parts.

the right side of the

system

deals with

deoxygenated blood.

the left side of the system

deals with oxygenated blood.

the size of your heart is equal to that of your fist

the human heart creates enough pressure in the left ventricle to squirt blood 9.1 metres

According to German researchers, the risk of heart attack is higher on Monday than any other day of the week.

human heart rate = 100,800 beats/day

fetal heart starts beating during fourth week of pregnancy

lowest blood pressure is in right atrium

Larry M. Frolich, Ph.D.,Human Anatomy

Location of Heart in Thorax

pg 523

Heart is located in the mediastinum area from the sternum

to the vertebral column and between the lungs

In thoracic cavity: mediastinum Apex points

slightly to left Base at “top” of

heart

100,000 hb/day ~3B hb/lifetime 4,000 gallons (15,000 L)

blood pumped/day ~60% of blood in veins

at any given time

In thoracic cavity: mediastinum Apex points slightly

to left Base at “top” of

heart Around heart:

pericardium Heart: three layers

Epicardium Myocardium Endocardium

Parietal pericardium Fibrous layer: dense

irregular c.t. (outside) Serous layer: moist

(inside) Turns inward at base

(top of heart) to form visceral pericardium

Visceral pericardium Covers heart surface

(epicardium) Pericardial cavity

Between parietal and visceral pericardium

Contains pericardial fluid

Pericarditis Cardiac tamponade

Epicardium = visceral pericardium Contains fat

deposits in sulci Other areas: thin

and transparent

Myocardium Cardiac muscle fibers Held together by

fibrous skeleton (collagenous and elastic fibers)

Recall: intercalated discs which contain gap junctions, desmosomes

Endocardium Endothelium

Continuous with vascular endothelium

What are the three layers of the heart?

Four chambers Two atria +

auricles Interatrial septum

Fossa ovalis Two ventricles

Interventricular septum

Four valves Atrioventricular valves

Right: tricuspid Left: bicuspid (mitral) Chordae tendinae Papillary muscles Prolapse

Semilunar valves Right: pulmonary

semilunar Left: aortic

semilunar

20-21

• Stethoscope• Sounds of heartbeat

are formed by turbulence in blood flow and valve closure– first heart sound

(lubb) is created with the closing of the atrioventricular valves

– second heart sound (dupp) is created with the closing of semilunar valves

Valve disorders Stenosis

Stiffened cusps; scar tissue occludes opening

http://www.heartcenteronline.com/myheartdr/common/articles.cfm?ARTID=187

Often rheumatic fever causes Autoimmune disease

attacks mitral valve: scarring and more heart work

Incompetent valve causes regurgitation and turbulence = heart murmur

Mitral valve prolapse (MVP) MVP can cause chest paint, fatigue and shortness of breath. Often, however, it is not dangerous. Much more common in women, particularly those between 20 and about 40.

From: http://www.healthatoz.com/healthatoz/Atoz/images/ency/00042848.jpg

Superior/inferior vena cavaEmpty into R

atrium Pulmonary trunk

At pulmonary semilunar valve: R/L pulmonary arteries

R/L pulmonary veins empty into L atrium

From: http://connection.lww.com/products/sadler/images/figurelarge11-46.jpg

Ascending aorta Brachiocephalic trunk

R common carotid artery and R subclavian artery

L common carotid artery

L subclavian artery Ductus arteriosus:

pulm. a. to aorta in fetus

Systemic vs. pulmonary circuit

Cor pulmonale: next slide

From: http://connection.lww.com/products/sadler/images/figurelarge11-46.jpg

From: http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/18131.jpg

Heart doesn’t get blood from chambers

Has its own vessels Two stem

immediately from ascending aorta

Left coronary artery (two branches) Anterior interventricular

branch Circumflex branch

Right coronary artery (two branches) Posterior

interventricular branch Marginal branch

Anastomoses Prevent

myocardial infarction

From: http://www.clevelandclinic.org/heartcenter/images/guide/disease/cad/artery7.JPG

A heart attack often involves a clot in the coronary arteries or their branches.

In this illustration, a clot is shown in the location of #1. Area #2 shows the portion of the damaged heart that is affected by the clot.

Image by J. Heuser courtesy of Wikipedia.

Coronary sinus 20% of blood

directly into right atrium

80% dumps into: Greater cardiac

vein Middle cardiac

vein To coronary sinus

to right atrium

Trace the blood flow through the heart, systemic and pulmonary circuits beginning at the right atrium. Be sure to include all valves, chambers and major blood vessels connected to the heart.

Coronary artery disease (atherosclerosis) Risk factors (9) Atherosclerotic plaque Thrombus and embolism

Heparin Coumadin (warfarin) (blocks synth.

Of II, VII, IX, X) Coronary artery bypass grafting Angioplasty with or without stent

(next page)

Heredity, age, gender (these three you can’t change!);

Obesity, diabetes, smoking, inactivity, hypertension (also, some researchers argue high cholesterol), stress.

Ischemia Angina pectoris Myocardial infarction

From: http://www.yourheart.org.uk/images/myocardial_infarction.jpg

Figure 1 (common iliac a.) Figure 2

On the left, a plastic tube is inserted into the coronary artery until it reaches the clogged area. In the middle diagram, a metal tip with a balloon attached is pushed out the end of the plastic tube into the clogged area. On the right, when the balloon is inflated, the vessel opens. Sometimes metal coils or slotted tubes, called stents, are inserted to keep the vessel open.

During this operation, the surgeon grafts segments of another vessel, usually a small vein from the leg, between the aorta and the coronary vessels, bypassing areas of blockage. Patients who require surgery often receive two to five bypasses in a single operation.

Specialized cardiac muscle cells in the SA node region initiate and send

impulses through the myocardium: Sinoatrial node (S-A node)

located in the right atrium near the superior vena cava rhythmic pacemaker

From the S-A node impulses are conducted along the interatrial muscle throughout the atrial myocardium with the help of the intercalated disks that connect all cardiac muscle fibers.

Atrioventricular Node (A-V nose) located in the inferior interatrial septum conducts impulses between the atria and ventricles

A-V bundle (Bundle of His) located in the interventricular septum divide into left and right bundle branches give rise to Purkinje fibers that carry impulses

throughout the ventricular myocardium

SA node fires spontaneously 90-100 times per minute

AV node fires at 40-50 times per minute If both nodes are suppressed fibers in

ventricles by themselves fire only 20-40 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

20-44

Myogenic cells Sinoatrial (SA) node:

innate rate: ~100 b/min Right atrial myocardium Primary pacemaker; slow

Na+ inflow ANS regulates

Atrioventricular (AV) node (Bundle of His) Single point of electrical

connection bet. atria and ventricles 40-50 bpm = nodal rhythm Damage = total heart

block 100 msec delay ANS regulates

AV bundle (right and left)

Purkinje fibers (conduction fibers)

heart conduction animation

Ectopic focus

Terminology Systole Diastole Normal

sinus rhythm: 60-100 b/min; 70 ave.

Tachycardia; >100

Bradycardia; < 60

palpitationsFrom: http://www.chez.com/deuns/ps/pression/p506.png

Wrists, ankles, six chest locations

Basic ECG waves P wave: atrial

depolarization and systole When SA fires

QRS complex: ventricular depolarization When AV node fires Note: this masks atrial

repolarization and diastole

S-T segment: beginning of ventricular systole

T wave: ventricular repolarization and diastole

Let’s look at it another way…

Size and timing of waves Significance of large waves

P wave: mitral valve stenosis Q wave: MI R: ventricular hypertrophy

Arrhythmias AV block Fibrillation

Heart receives visceral motor innervation Sympathetic (speeds up) Parasympathetic (slows

down) p. 534

Larry M. Frolich, Ph.D.,Human Anatomy

3 types of vessels Arteries Capillaries Veins

Blood vessel wall consists of 3 layers:

• Tunica externa– Outermost layer– CT w/elastin and collagen– Strengthens, Anchors

• Tunica media– Middle layer– Circular Smooth Muscle– Vaso-constriction/dilation

• Tunica intima– Innermost layer– Endothelium– Minimize friction

• Lumen

- Large Thick-walled, Muscular Elastic Oxygenated blood

Exception Pulmonary Artery Carried under great pressure Steady pulsatingArterioles: smaller vessels, enter tissue

Carries blood that contains waste and CO2 Exception pulmonary vein

Blood not under much pressure

Valves to prevent much gravity pull

Venules: larger than capillaries

Arteries (aa.) Veins (vv.)Direction of flow

Blood Away from Heart

Blood to Heart

Pressure Higher Lower

Walls THICKER: Tunica media thicker than tunica externa

THINNER: Tunica externa thicker than tunica media

Lumen Smaller Larger

Valves No valves Valves

Microscopic--one cell layer thick

Network Bathed in

extracellular matrix of areolar tissue

Entire goal of C-V system is to get blood into capillaries where diffusion takes place

20-59

SVC/IVC

Lungs

Left Atrium

Pulmonary Arteries

Pulmonary Veins

Aorta Left Ventricle(aortic semilunar valve)Body

Body

bicuspid (mitral) valve

(pulmonary semilunar valve)

Passage of Blood through the Heart

Right Atrium (tricuspid valve) Right Ventricle→

Pulmonary trunk

Pulmonary Circuit

Systemic Circuit

Systemic Circuit

Regular exercise Weight control Well balanced diet Do not smoke Diet low in

saturated fat

THANK YOU…