Cardiac cycle part of the test
Cardiac muscle cells
branching networks connected by intercalated disks that transmit action potential to networks of cells
functional syncytium
Mass of cells that work as a unit
Atrial syncytium
functional syncytium in the atria
Ventricular syncytium
functional syncytium in the ventricles
What's the difference between cardiac muscle cells and skeletal cells?
Cardiac Muscles are found in the Heart and are involuntary muscles. Skeletal Muscles are attached to the bones and are voluntary in nature
What separates the atrial syncytium and ventricular syncytium
Separated by connective tissue
Systole
contraction of syncytium
Diastole
relaxation of syncytium
What direction does blood move?
from areas of high pressure to low pressure (gradient)
What will increase pressure?
contraction (systole)
What will decrease pressure?
relaxation (diastole)
Lubb
1st heart sound, from AV valves closing
Dubb
2nd sound, from SL valves closing
What happens to the atria during diastole?
Atria fills and pressure becomes greater than in the ventricles
What happens to the AV valves?
the atria filling causes them to open during diastole, allowing ventricles to fill
What happens to the atria during systole?
pressure continues to rise and forces the blood into the ventricles
What happens in the ventricles during systole?
the pressure in the ventricles increases sharply- AV valves close (lubb) and SL valves open
What does ventricular systole cause the blood to do?
be pushed out of the ventricles completely
What happens when all the blood is pushed out of the ventricles?
pressure drops and the vents relax (ventricular diastole)
What causes SL valves to close (dubb)?
the ventricular pressure being lower than pressure in the aorta and the pulmonary trunk
When does the heart relax?
for a brief moment before AV valves open and the cycle begins again
Cardiac Conduction system
5 specialized cardia muscle tissue conducts impulses through the myocardium
What do the cells in the myocardium do in the cardiac conduction system?
they don't contract, but initiate and distribute impulses in the heart
Components of Cardia Conduction System
CCCS
CCCS: Sinoatrial (SA) Node
self-exciting mass of specialized cardiac muscle that initiates atrial contraction
CCCS: Atrioventricular (AV) Node
passes impulse to AV bundle, delaying the signal until atria have finished emptying
CCCS: AV bundle of His
impulse received from AV node & continues down septum
CCCS: Bundle Branches
Av bundle divides into left and right bundle branches
CCCS: Purkingi fibers
spread impulses to ventricular wall and papillary muscles
pressure and polarizing relationship
Polarizing- relaxation
Depolarizing- contraction
Electrocardiogram (ECG/EKG)
Measures electrical activity of the heart
P wave - first bump
Atrial depolarization which leads to contraction of the atria
QRS Complex- tall spike
Ventricular depolarization leads to the contraction of the ventricles and the repolarization of the atria
T wave- second bump
Ventricular repolarization, leads to ventricular relaxation
What things can influence a cardiac cycle?
Emotions
increased body temp
Concentration of ions (amount of electrical nodes) [Ca+ K+]
Tachycardia
abnormal heartrate greater than 100 beats per minute
Badycardia
abnormal heartrate less than 60 bpm
Regulation of the Cardiac System
RCS- Amount of blood pumped must adjust to current needs (EX: excersize)
RCS- Cardiac center
medulla oblongata
RCS- Medulla Oblongata
maintains balance between sypathetic & parasympathetic,divisions of anonomic nervous system
RCS- Symathetic impulses
increase the speed & strength of heart contraction
RCS- Parasympathetic impulses
Decreases heartrate