Download Cardiovascular System Notes

The Circulatory System
Chapter 18-19
The Heart
-Size of your fist
-In thoracic cavity between lungs
-Rests on diaphragm
Structure
-hollow, cone-shaped
-enclosed in pericardium (fibrous membrane)
Pericardium
Visceral pericardium (epicardium)
-layer of pericardium that is in contact with the heart
Parietal Pericardium
-outer layer of pericardial sac
Paricardial Cavity
-layer between visceral and
parietal, contains serous fluid to
help reduce friction
Pericarditis – inflammation of pericardium
-caused by bacterial or viral infections
-layers stick together and interfere w/ heart
movements
Wall of Heart
Epicardium – protective layer
-connective tissue covered by epithelium
Myocardium – thick layer of cardiac muscle
-richly supplied with blood
Wall of Heart
Endocardium – consists of epithelium and connective
tissue
-many elastic and collagenous fibers
Chambers and Valves
The heart has 4 chambers : 2 left, 2 right
Atria (Atrium) – upper chambers
-thinner walls
-receive blood from veins, or returning to the heart
Chambers and Valves
Ventricles – lower chambers that pump blood through
arteries to the rest of the body.
-thicker muscle or wall b/c they pump blood
further
Septum – separates the right and left sides.
Right Side of Heart
-Right atrium receives blood from superior vena cava,
inferior vena cava, and coronary sinus
-Tricuspid valve guards opening between R. ventricle
(chordae tendineae) and R. atria
-Right ventricle pumps blood to the lungs
-thinner muscular wall than left ventricle
Chordae tendinae
-orignates from the sm muscle tissue (papillary muscles)
and projects inward from the walls of the ventricle.
Left side of Heart
-Left atrium receives blood from the lungs through
4 pulmonary veins
-Bicuspid (mitral) valve guards opening between L. atrium
and L. ventricle
-Left ventricle pumps blood to the rest of
the body through the aorta. The R and L
coronary arteries branch off of the aorta to
supply the heart muscle.
-thick muscular wall
-aortic valve (semilunar valve) prevents
blood from flowing back into heart
Pathway of Blood
Right side receives blood low
in O2 and high in CO2
Right ventricle pumps blood
to the lungs (pulmonary
circuit)
Left side receives blood from
Lungs: high in O2 and low in
CO2
http://www.medtropolis.com/VBody.asp
http://www.pbs.org/wgbh/nova/heart/heartmap.html
Heart Blood Flow
1. From superior and inferior vena cava
2. Into the R. atrium
3. Past the tricuspid valve into
the R. ventricle
4. Through the semilunar valve
into the pulmonary artery
to the lungs
5. From the lungs through the
pulmonary veins into the L.
atrium
6. Through the bicuspid valve (mitral)
into the L. ventricle
7. From the L. ventricle past the semilunar
valve to the aorta
8. Blood is transported to the body through
arteries, arterioles, and capillaries.
O poor blood
9. Venous blood travels back through venules and then veins
2
O2 rich
Blood Supply to Heart/Coronary Circulation
-Heart needs a steady supply of oxygenated blood
-Right and left coronary arteries branch off of aorta and
supply blood to the muscle cells of the heart
-Coronary sinus empties into R. atrium (carries venous
blood)
http://www.bidmc.org/YourHealth/Procedure
sInMotion.aspx
Angina – severe chest pain
Ischemia – reduced blood flow to tissue
Coronary Artery Disease (CAD)
– reduced blood flow to myocardial tissue due to clogged
or blocked arteries.
1. Atherosclerosis – hardening of arteries, calcifying of lipids
in blood vessels making them hard and
brittle.
2. Myocardial infarction – tissue death often leads to heart
attack b/c blood clot or clogged.
Treatments – angioplasty, stents, bypass surgery
http://www.hhmi.org/biointeractive/stemcells/video.html
http://wn.kktv.com/category/60673/medical-3danimation-heart-attack
http://www.heartinfo.org/ms/animations/13/main.html
http://www.nhlbi.nih.gov/health/health-topics/topics/heartattack/causes.html
Heart Attack,
Cholesterol, Laser
Angioplasty
http://www.hhmi.org/bi
ointeractive/media/hear
t_attack-lg.mov
http://health.india.com/diseasesconditions/what-is-a-heart-attack-animation/
Heart Sounds (Dub – Dub)
Lubb = 1st part of sound (systolic)
-ventricles contract…empty
-tricuspid and bicuspid valves close (A-V valves)
Dupp = 2nd part of sound (diastolic)
-ventricles relax…fill
-pulmonary and aortic semi-lunar valves close
*Heart murmurs – abnormal sounds that
may indicate problems with
valves
Cardiac Cycle
Cardiac cycle = one complete heartbeat
-Takes about .8 seconds
-The atria contract while the ventricles relax
-Ventricles contract while atria relax
R. Ventricle
L. Ventricle
lungs
body
Cardiac Cycle Cont.
Sinoatrial Node (SA Node)
-Small mass of tissue that stimulates contractions
in the heart (interatrial fibers stimulate the left atria)
-Called the pacemaker of the heart
-Responsible for the rhythmic contractions
-Stimulates atria to contract
p565 Fig 18-11, p595 Fig 19-1
Cardiac Cycle Cont.
Atrioventricular node – (AV Node)
-Specialized muscle tissue in the floor of the R. Atrium
-Internodal fibers connect the SA Node to the AV Node
-Delayed impulse allows the atria
to empty and ventricles to refill.
-As impulse travels through the
AV bundle (bundle of His) the
impulse travels more rapidly
Cardiac Cycle Cont.
-Purkinje fibers: function in transmitting the impulse
from the AV bundle to ventricular muscles to contract
and force the blood into the arteries
-The Purkinje fibers stimulate the papillary muscles
Electrocardiogram (ECG)
-A recording of electrical
chgs occuring within the
heart
-Electrodes placed on the
skin and connected by wires
-A pen records any electrical changes
P Wave – depolarization of atria… “atrial contraction”
QRS – depolarization of ventricles and atrial repolarization
“ventricular contraction”
T Wave – repolarization of ventricles
http://www.getbodysmart.com/ap/circulatorysystem/heart/electricalevents/ecg/tutorial.html
http://www.ecgrhythmcourse.com/look_inside.cfm
P599 Fig 19-4
Regulation of Cardiac Cycle
-Parasympathetic fibers secrete acetylcholine
-slows down heart, dec rate of contractions
-Sympathetic fibers secrete norepinephrine
-increases rate of contractions
-Cardiac center is located in medulla oblongata
-receives sensory info from various parts of
circulatory system
-responds to anxiety, fainting, temp change, ion
concentration (K+, Ca+2)
Blood Vessels
Arteries – strong, elastic vessels that carry oxygenated blood
away from heart under high pressure…exception
p. artery
-thick walls
-arterioles : small arteries that join to capillaries
Vasoconstriction – muscle fibers contract and decrease
vessel diameter
Vasodilation – muscle fibers relax and increase vessel
diameter
Both tunica media and tunica adventitia are absent in veins and capillaries
Blood Vessels
Venules & Veins
Veins – deoxygenated blood to the
heart..exception p. veins
*thinner walls
*blood reservoir
*low pressure
Venules – small veins, that join to
capillaries.
Sinuses - lg venous spaces
Blood Vessels
Capillaries
-microscopic vessels that carry blood
from arterioles to venules
*thin endothelium- allows for ease of
transport across membranes
*Blood pressure dec as the distance from
the heart inc.
Blood Pressure
-The force blood exerts against
the inner walls of blood vessels
Systolic pressure - maximum pressure achieved during
ventricular contraction (arterial pressure).
(pressure while heart is beating)
Diastolic pressure - the lowest pressure that remains in the
arteries before the next ventricular
contraction. (resting stage between beats)
Ventricles are
filling up/relaxed
Ventricles are
emptying/
contracting
Normal
120 Systolic
80 Diastolic
Prehypertension
120-139
80-89
Hypertension
140 or more
90
Pulse pressure = diff between systolic
and diastolic pressures
Congestive heart failure – (left side failure) left ventricle decreases
pumping pressure in systemic circulation which then causes fluid to
build up
Cardiomyopathy - is a weakening of the heart muscle or a change
in heart muscle structure. It is often associated with inadequate
heart pumping or other heart function abnormalities.
Congenital heart disease - Congenital heart disease refers to a
problem with the heart's structure and function due to abnormal
heart development
Aneursym – is a bulge or ballooning of the artery which can grow
and burst and possibly cause death.
Geogina – “Whatever”
Wilber – “Whity / asian”
Phil – “The
Butcher’s son”
Babe – “Demented”
possibly TOURETTS
Ethel –
“Spacy”
Moo
The green runt
Lafawnda
“The best
behaved”
Pork chop
Lunch!!
ELLE – THE BOSS!!!
Don’t forget to wish you mother
Happy Mother’s Day
on Sunday!!!