4.7.25 lecture: pericardium and myocytes

what generates the pressure of the heart?

myocardium

what lines the inside of the heart?

endocardium (epithelial cells)

the endocardial layer is made of _____________________ and is continuous with the ____________________________

simple squamous epithelium; endothelium of the blood vessels

what surrounds the heart?

pericardium

the pericardium is a __________________ membrane

serous

what is a serous membrane made of?

loose areolar connective tissue outside, simple squamous epithelium inside

what's on the inside of a serous membrane?

ground substance and hyaluronic acid

as the myocardium moves, so does the ________________ layer of the pericardium

visceral

the region of the pericardium not in contact with the myocardium is the _________________ layer

parietal

what's the point of the serous membranes?

to reduce the amount of friction the organs experience

inflammation within the pericardium is called _________________

pericarditis

what does pericarditis mimic?

heart attack symptoms

what is the purpose of the myocardium?

generates the forces that produce blood pressure

is a cardiac myocyte big or small?

very very small, can't see without a microscope

why are cardiomyocytes branched?

this allows them to wrap around the odd shaped heart

what part of the left ventricle is shared by the right ventricle?

interventricular septum

why is it deadly when a kid is born with their heart plumbed backwards?

the right ventricle can't withstand high pressure

the majority of the ventricle walls are made of ____________________

cardiac myyocytes

what do we not have between cardiac myocytes? why?

neuromuscular junctions; automaticity

what do we mean by automaticity?

conduction is propagated by GAP JUNCTIONS

what do we mean when we say cardiac myocytes have a very long absolute refractory period?

it takes a long time for a new action potential to be generated

true/false: the heart can operate anaerobically just like skeletal muscle

HELL NO, never

name the top 3 favorite energy sources of the heart in order:

1. lactate

2. fat

3. carbohydrates

what are the dark lines between the myocytes?

intercalated discs

what is an intercalated disc?

the boundary between 2 cardiac myocytes

why do intercalated discs stain dark?

lots of desmosome and gap junction proteins

what do the desmosomes do?

they help withstand the pressure

what's the name of the membrane of the cardiac muscle?

sarcolemma

what invagination of the sarcolemma is present in the cardiac myocytes?

t tubule

what does the t tubule reach down to?

the sarcoplasmic reticulum

what are myofibrils?

they are where we find the sarcomeres

what contains the contractile muscles for cross bridge cycling?

sarcomeres

how do we describe contraction in a cardiac myocyte?

sliding filament theory

the _________ filaments slide past the ________ filaments

thin; thick

how do the filaments slide?

cross bridge cycling

what does muscle do?

converts chemical energy into force and heat

what are the blood vessels that supply the heart called?

coronary blood vessels