PHYL142L Unit 2: Heart Conduction System

interatrial or interventrical septum

separation of heart longitudinally

ventricles

what forces blood out of the heart?

4 valves

what helps to facilitate blood flow through the chambers?

tricuspid, mitral (bicuspid)

what are the atrioventricular valves?

pulmonary, aortic

what are the semilunar valves?

epi, myo, endocardium

what are the layers of the heart?

heart

cone shaped organ, size of your fists and sits slightly to the left of your body

lungs

what flanks the heart on both sides?

protection and lubrication

what is the function of the epicardium?

thickest, muscle, intercalated discs at cell junctions

what is the function of the myocardium?

inner lining

what is the function of the endocardium?

junctions called intercalated discs

what are heart muscles connected by?

functional syncytium

when muscles coordinate contractions as a singular unit

cardiac pacemakers

heart beats are intrinsic through what?

single unit, sort of like a wave

depolarization occurs from atria to ventricle so the heart beats as a ___

sinoatrial node, atrioventricular node, av bundle (bundle of his), bundle branches, purkinje fibers (subendocardial conducting network)

state the conduction system’s structures in the order of their pathway

sinoatrial node (pacemaker)

what structure of the intrinsic conduction system generates impulses?

atrioventricular node

the impulse that the sinoatrial node makes gets paused for 0.1 seconds where?

atrioventricular bundle

what structure of the intrinsic conduction system conducts the impulse to the bundle branches?

bundle branches

what structure of the intrinsic conduction system conducts the impulse through the interventricular septum

subendocardial conducting network

what structure of the intrinsic conduction system depolarizes the contractile cells of both ventricles

electrocardiogram (ECG, EKG)

what are the impulses of the heart measured by?

P wave, QRS complex, T wave

what are the usual 3 waves of an electrocardiogram?

tachycardia

heart rate over 100 beats/min

bradycardia

heart rate below 60 beats/min

leads

what does the EKG use to measure conduction patterns?

Einthoven’s triangle

what forms 3 limb leads of the electrocardiographic readings (2 shoulders and pubis landmark) extending to the limbs

Willem Einthoven, used to demonstrate the first EKG

who was the EKG triangle discovered by? what was it used to demonstrate?

Lead I

ECG Lead(s) that reads electrical activity spreading horizontally from the heart

Lead II and Lead III

ECG Leads that reads vertically, but to different targets

Lead III

what ECG Lead has a larger target area

systole

ventricular contraction

diastole

ventricular relaxation

cardiac cycle

consist of one complete heartbeat where both atria and ventricles contract, then relax

approx. 1.6 seconds

how long is the cardiac cycle

60-80 bpm or 75 bpm

what is the average heartbeat?

quiescent period

when the total heart is relaxed

0.4 secs

how long is the quiescent period?

turbulent blood flow

what leads to heart sounds?

Lub

closure of AV valves (beginning of systole)

Dup

closure of semilunar valves (end of systole)

Murmurs

abnormal heart sounds, indicate valvular problems

stethoscope

distinct valve sounds can be heard using what?

pulse

alternating surges of pressure in artery with each contraction and relaxation of the left ventricle

pulse pressure

difference in systolic versus diastolic pressure

pulse rate

heart rate is also called

blood pressure

pressure blood exerts against any unit area of blood vessel walls

arteries

where is blood pressure usually measured?

systolic pressure and diastolic pressure

what are the 2 kinds of blood pressure that are taken?

systolic pressure

arterial pressure at peak of ventricular contraction

diastolic pressure

arterial pressure during ventricular relaxation

sounds of Korotkoff

what indicates the resumption of blood flow through the forearm after cuff pressure is gradually released?

sphygmomanometer

blood pressure is measured using a blood pressure cuff or (?)

face and extremities color; excessive perspiration and coldness to touch

what are obvious external signs of inefficient blood circulation