Cardiovascular Part 2 Flashcards
What is the paricardium
doubled walled sac filled with a think layer of clear pericardial fluid = lubricant to allow heart movement without friction
What are the general purpose of Heart valves?
to maintain a one way blood flow direction
What are the 2 types of valves?
- Atrioventricular vaves (AV) = control movement from atrium –> ventricles (have tendons attached)
- semilunar valves = one-way valves that exist between the ventricle & outflow arterie
Do AV valves have tendons that attach to pappilorry muscle?
Yes - but the tendons don’t open/close valves, they only provide support. The pappilory muscle hold flaps in place and make sure there is no backward blood flow
How are AV valves opened?
valves open in response to the pressuere recieved on the flaps by the atrium
What are 2 types of AV valves
- RST = Right Side Tricuspid
- Mitral = bicuspid (left)
What are the 2 types of semiclunar valves? Location? How do they differ to AV vavlves?
1.Aortic valve
2.pulmanary valve
3.do not have have tendons
Ventricular contraction/relaxation uses which 2 valves?
during ventricular contraction AV valves stay CLOSED to prevent backward blood flow
in venticurlar relaxation semi lunar valves prevent backward blood flow
Where do cardiac AP originate?
in a group of cells in the SA node (pacemaker cells)
AP then spreads via autorythmic cells
Which cell group (SA node/ AV node / Perkinji fibers) determines the heart ?
the group of auto cells with most pacemaker actiivty = SA node
since AV node and perkinji fibers have slower pacemker activity
List the pathway of the cardiac conduction system
SA node –> internodal pathways –> AV node (bundle of His) –> AV bundle –> bundle branches –> perkinji fibers
gap junctions in cardiac cells connect autorythmic & contractile cells allowing for uniform contraction in the __ first, which then spreads to the ventrical
atrium contraction first, then ventricle contraction
What is an ECG
Electrocardiogram = represents the summed electrical activity of all cells (of the heart) recorded from the surface of body
what do The direction of deflications in an ECG?
they tell us the direction of the electrical activity of the heart (=measure direction of current)
They don’t tell us type of current (depolarization/repolarzation = both reflect upwards)
What does an upward deflection on an ECG mean?
current is moving towards the + electrode
What does a downward deflection in an ECG mean?
current is flowing towards the - (neg) electrode
What does a straight line mean on an ECG?
activity is moving perpindicular = no deflections
ECG are a combinations of what 3 things?
- Waves = deflections upward/downward
- Segments = sections between 2 waves
- intervals = combo of waves & segments
How can arrythmias (patologies) appear on ECG?
as elongated segments/intervals, alterad or missing waves
What is premature ventricular contraction>
when our perkinji fibers randomley kick, becomeing the new pacemaker = shown as a skiped beat or palpatations
What is Long QT syndrome?
u have a mutation in ur K/Na channels = that makes a longer platue = delayed repolarization
The cariac cycle consists of one complete __ and __
cardiac cycle = 1 contraction & relaxation
What are the 2 primary phases of the cardiac contraction cycle?
Diastole = time which cardiac muscle releaxes
systole = time during which cardiac muscle contracts
ventricles don’t contract & relax at same time
What are the 2 primary phases of the cardiac contraction cycle?
Diastole = time which cardiac muscle releaxes
systole = time during which cardiac muscle contracts
ventricles don’t contract & relax at same time
What are the 5 phases of the cardiac cycle
- Atrial + Ventrical diastole / late diastole (relaxing) = heart at rest
- Atrial systole (contraction) = completionof ventricular filling
- Isovolumetric ventricular contraction = early ventricular contraction
- Ventricular ejection = the heart pump blood out
- Isovolumetric ventricular relaxation / early diastole = ventricular relaxation
List 3 types of cardiac volume, and what they are?
- EDV - end diastolic volume = maximal volume in the ventrical (after ventricular filling, and before contraction?)
- ESV - end systolic volume - minimal aount of blood left over after ventricular contraction
- SV = Stoke volume = amount of blood ejected during a single ventricular contraction
How is stroke volume calculated?
stroke volume = end diastolic - end systolic
What factorss influence stroke volume?
- autonomic nervous sytem
- venous return
- drugs
What is an ejection fraction?
% of end diastolic volume that is ejected from the heart (fractionof blood ejected per beet)
EF = SV / EDV
List normal EDV / ESV / SV / & EF values
EDV = 135ml
ESV=65ml
SV=70ml
EF=52%
How is total blood blow (aka cardiac output calculated)
CO= heart rate x stroke volume
CO = HR * SV
What is cardiac output?
flow of blood delevired from ONE VENTRICLE in a given time period
What is cardiac output?
flow of blood delevired from ONE VENTRICLE in a given time period
What is the average CO?
5 mL/min
CO is determined by which 2 fatcors?
stoke volume & heart rate
what factors impact Heart rate?
sympathetic activty (activate beta-epinephirin cells) = directly related to HR
parasympatheitc actiivty = inversly porportional to HR
hormne releas? (directly to HR?)
What factors determines stroke volume?
stoke volume is direcly proportional to force of contraction
What factors influnce force of contraction?
contractility
inital fiber length
What factors control
