Heart Flashcards
constant motion of a fluid
flow
physical force required to create flow through any tube
pressure
pressure and force have an inverse relationship
boyle’s law
difference between area of high pressure and area of low pressure
pressure gradient
prevent backflow and ensure one-directional flow of blood
valve
the heart is a double___
pump
Decreases chamber volume
Increases chamber pressure
Contraction
Increases chamber volume
Decreases chamber pressure
relaxation
What is this?
___ and ___ pumps work in ____.
They are connected to each other and highly ____.
___ and ___ together
Pumps roughly the same volume of ___.
coordination of the beating heart
pulmonary
systematic
parallel
coordinated
contracts
relax
blood
The heart is located in the __ ___,Protected by the ____.
Thoracic Cavity
Pericardium
outer layer, made of dense regular connective tissue
fibrous pericardium
double-layered, pericardial fluid-filled membrane
Serous pericardium
outermost layer, in contact with fibrous pericardium
parietal layer
surrounds and is continuous with surface of the heart
Visceral layer
The heart is a ___ organ
multilayer
Multilayers: (3)
Epicardium
myocardium
endocardium
outermost layer, made of loose areolar connective and adipose tissue
epicardium
thickest layer, contains cardiomyocytes and cardiac skeleton
myocardium
deepest layer, made of simple squamous endothelial tissue
endocardium
Heart has four chambers:
Two upper chambers known as ____
Two lower chambers known as ____
Left and right side are separated by _____
Left atrium + left ventricle = ____ ___ (pumps _____blood)
Right atrium + right ventricle = ___ ____ (pumps _____ blood)
atria
ventricles
cardiac septum
systematic pump
oxygenated
pulmonary pump
deoxygenated
_______ blood enters right atrium from body through superior (upper body) and inferior (lower body) vena cava
Pumped through ____valve to ____ventricle
Blood exits heart through ____ arteries into ____ circulation
_____ blood returns through pulmonary____into the ____ atrium
Pumped through ____ valve into ___ ventricle
Blood exits heart through ____ into ____ circulation
De-oxygenated
tricuspid
right
pulmonary
pulmonary
oxygen-rich
veins
left
mitral
left
aorta
systematic
small hole that allows blood to bypass the right ventricle, moving directly between right atrium and left atrium
foramen ovale
connects pulmonary trunk to aorta
ductus arteriosus
Have a single, centrally-located ____
__ and __
Myofilaments are arranged into ____
___ are less pronounced
Myofibrils are ___ and_____ in size
Have great abundance of ___
Resist fatigue through ___ metabolism
Being to die after a few minutes without __
Sarcoplasmic reticulum lacks ____
Membranes are ____ together
Entire tissue functions together (___) and is ____
features of cardiomyocytes
nucleus
short
wide
sarcomere
striations
branched
variable
mitochondria
aerobic
O2
cisternae
fused
syncytium
auto rhythmic
Action Potential in Contractile Cardiomyocytes (5)
- Resting Membrane
- Depolarization
- Transient Repolarization
- Plateau Phase
- Rapid Repolarization
Typically between -80 mV and -90 mV
Created from continuous efflux of K+ through inward rectifier potassium channels (KIR)
Also small amount of Ca2+ and Na+ permeability
Na/K/ATPase serves to maintain concentration gradients
Resting membrane
Similar to the process in skeletal muscle
Voltage-gated fast sodium channels (Naf) are activated, allowing influx of positively-charged sodium ions
Depolarization
Voltage-gated sodium channels rapidly inactivate at the peak of the action potential
Sodium permeability decreases
Cardiomyocytes go into a refractory period
Membrane potential begins to hyperpolarize due to transient outward current from potassium channels
Transient Repolarization
Voltage-gated L-type calcium channels (CaL) open, bringing positively-charged Ca2+ ions into the cell
Plateau Phase
L-type calcium channels close
Efflux of K+ continues through voltage-gated potassium channels
Membrane potential repolarizes to resting state
Rapid Repolarization
____ is Due to pacemaker cells
Autorhythmicity
Pacemaker Cells (3)
- Pacemaker potential
- rapid depolarization
- Repolarization
Delayed rectified channels (KDR) allow constant efflux of K+, steadily increasing membrane potential
Pacemaker Potential
Inward sodium (funny current) and transient calcium influx continue depolarization until the threshold of the voltage-gated L-type calcium channel is reached
T-type calcium and HCN channels close
Rapid Depolarization
L-type calcium channels close at peak of action potential
Inward rectifying potassium channels (KIR) open
Increased permeability to K+ returns cell to hyperpolarized membrane potential
Repolarization
Family of disorders characterized by abnormal electrical activity within the heart
Cardiac Arrhythmias
An _____Provides an Electrical Picture of Heart Function
electrocardiogram
ECG Leads Are Placed in _____ Formation
Triangle (Einthoven’s Triangle)
depolarization of atria
P wave
: ventricular depolarization
QRS complex
depolarization of septal region of ventricle
Q wave
depolarization of anterior region of ventricle
R wave
depolarization of inferior portions of ventricle
S wave
ventricular repolarization
T wave
time required for atrial depolarization and action potential to reach ventricles
P-Q interval:
time required for atrial depolarization to propagate through the ventricles
P-R interval:
time course of ventricular depolarization
S-T segment
combined time required for ventricular depolarization and repolarization
Q-T interval
The___ of cardiac contraction is____to the amount of ____ released into the cytoplasm during excitation-contraction coupling
force
proportionate
calcium
