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