Lecture 3 & 4: Muscle and Osmosis

Hypertonic

low solute outside - burst

Hypertonic

high solute outside - shrivel

Isotonic

no change equilibrium

Aquaporins

membrane proteins that allows movement of water

Severe dehydration

give pt hypotonic to allow cell to intake water then switch to isotonic

Sarcomere

functional unit of skeletal muscle

Four proteins of the sarcomere

actin, myosin, troponin, tropomyosin

Actin

thin

Myosin

thick

myosin has attatchment to

actin and ATP

Actin has attachment to

myosin, troponin

Myosin binding sites regulation

located on actin, covered by tropomyosin that is held in place by troponin till Ca2+ binds to troponin, moving tropomyosin to move exposing the myosin binding site

Titin

elastic portion of the sarcomere helps with stretch and release in contractions

Organophosphates (pesticides)

block AChE; depolarizing block, ACh does not get broken down, constant conraction

Vecuronium

paralytic agent used to keep muscles quiet during surgery; ACh antagonist; blocks ACh from binding to nicotinic receptors to stop EPP