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THE HEART. Position of the Heart. human heart is about the size of a fist lies in the thoracic cavity w/in the mediastinum (area from sternum to vertebrae, between the lungs) tilted @ angle so its inferior surface lies against the diaphragm. Parts of the Heart. - PowerPoint PPT Presentation
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THE HEART
Position of the Heart human heart is about the size of a
fist lies in the thoracic cavity w/in the
mediastinum (area from sternum to vertebrae, between the lungs)
tilted @ angle so its inferior surface lies against the diaphragm
Parts of the Heart Base of the heart
is its superior border
Apex of the heart is lowest point
Major Heart Structures:the Pericardium Outer Layer: Fibrous Pericardium
tough, attaches to diaphragm
Inner Layer: Serous Pericardiumdbl membrane: ○ outer parietal: attaches to fibrous pericardium ○ inner visceral layer: covers cardiac muscle
between the 2: pericardial cavity filled with serous fluid
Wall of the Heart 3 layers1. outer epicardium
same as visceral pericardium2. middle myocardium
cardiac muscle3. inner endocardium
thin layer of endothelium that lines inside chambers of the heart & valves
Surface Features of the Heart 4 chambers of heart:
2 atria form the base ○ Auricles (ear-like) pouch-like extensions
tip of left ventricle forms the apexSulci: grooves where coronary blood vessels
& adipose tissue that externally mark the boundaries between the 4 heart chambers○ coronary sulcus: separates atria from
ventricles○ anterior & posterior interventricular sulcus:
separate 2 ventricles
Right Atrium Receives
deoxygenated blood from SVC & IVC
Right Atrium inside surface has honeycombed
appearance & ridges called pectinate muscles
wall separating rt & lt atrium= interatrial septum: in fetus hole called foramen ovale (blood shunts from rt atrium lt atrium avoiding pulmonary circulation); when scarred over called fossa ovalis
Right Ventricle receives blood
from right atrium sends blood to
pulmonary trunk lungs to be oxygenated
Right Ventricle inside has ridges
of muscles called trabeculae carnae: largest ones called papillary muscles: have string-like cords called cordae tendinae
Right Ventricle separated from left ventricle by:
interventricular septum
Left Atrium receives
oxygenated blood thru 4 pulmonary veins
delivers blood to left ventricle
seen on posterior surface of heart
Left Atrium thin-walled identifiable characteristic: 4
pulmonary veins entering it
Left Ventricle receives oxygenated blood from
left atrium sends blood to systemic circulation
thru Aorta has thickest muscle (pumps blood
the farthest)
4 Heart Valves control 1-way flow of blood 2 AV valves
between atria & ventriclesTricuspid : rt AV valveMitral : lt AV valve, aka bicuspid
2 semilunar valvesblood exits rt ventricle thru Pulmonary
(semilunar) valveblood exits lt ventricle thru Aortic
(semilunar) valve
AV Valves Tricuspid valve Mitral Valve
Semilunar Valves Pulmonary Valve Aortic Valve
Blood Flow thru the Heart thinner walled atria receive blood
returning to heart from veins pressure of blood in filled atria
opens the AV valves & most of the blood flows into ventricles
both atria contract simultaneously to pump remaining blood into ventricles
Blood Flow thru the Heart when atria have stopped
contracting AV valves close Ventricles contract together forcing
semilunar valves open walls of left ventricle thicker
providing more force to pump blood thru systemic circulation
Blood Flow thru the Heart Ventricular Systole:
when both ventricles are contractingAV valves closeSemilunar valves open
Ventricular Diastole: when both ventricles relaxedSemilunar valves closeAV valves open
Cardiac Cycle
Systemic & Pulmonary Circulation
Heart Animations http://www.nhlbi.nih.gov/health//dci
/Diseases/hhw/hhw_pumping.html http://www.hybridmedicalanimation
.com/work/animation/beating-heart-with-blood-flow/
Heart Sounds Auscultation: listening to body
sounds 1 heartbeat produces 2 heart
sounds: lub-dub heart murmurs: abnl heart sounds
usually due to valve abnl
http://www.blaufuss.org/tutorial/index1.html
Heart Sounds http://www.dnatube.com/video/921
7/Review-of-heart-sounds
http://familymedicine.osu.edu/products/physicalexam/exam/flash/heart/heart2.cfm
http://www.blaufuss.org/tutorial/index2.html
Pulse when ventricles contract a blood
pressure wave is produced that travels in the arteries and can be felt as your pulse
radial pulse: check over radial artery
carotid artery pulse: check over carotid artery
Calculate Pulse Count the # of beats in 15 s and
multiply x 4 If the math is too difficult count for
30 s and multiple x 2
Blood Pressure pressure exerted by blood against
blood vessel walls highest in the aorta & large elastic
arteries & decreases as arteries get smaller & further from heart
Systolic Blood Pressure top # on a BP pressure generated by ventricular
systole normal adult: ~120
Diastolic BP bottom # on BP pressure exerted during ventricular
diastole normal adult: 60- 80
Arterial Blood Pressure normal adult ~ 120/80
normal venous BP: ~16 mm Hg
BP Measurement Sphygmomanometer: BP cuff usually use brachial artery use correct size cuff
BP pump used to inflate cuff to a
pressure > the systolic pressure:puts pressure on the artery, flattens it,
& stops blood flow in the arterypressure slowly released from cuff as
stethoscope used to auscultate over brachial artery
BP reported in mm Hg as pressure in cuff becomes <
pressure in artery…examiner will hear a sound can be heard, caused by the turbulent flow of blood as artery goes from flattened normal