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…
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