Hubs Flashcards
Diffusion?
movement of molecules from high concentration to low concentration
Osmosis?
movement of water across membrane to equalise conc
Exctracellular space
outside of cell
intracellular space
inside cell
isotonic
ECF and ICF are balanced
ECF and ICF
extra/intracellular fluid
hypertonic
Too much water inside the cell, water moves out of the cell to become isotonic
hypotonic
too much water outside of the cell, water moved into the cell to become isotonic
chemical gradient
uneven distribution of molecules on either side of the membrane
Slightly more positive
outside
slightly more negative
inside
what does chemical and electrical signalling allow
rapid signaling of excitable cells
passive ion channels
allows the movement of ions down their chemical/electrical gradient
Active Ion pump
Pumps ions against their chemical/electrical gradients to maintain the gradient across the membrane, requires ATP
resting membrane potential?
inside of the cell has a more negative charge than the outside which creates and electrical gradient
depolarisation
positve ions enter the cell which acts as a signalling event for excitable cells
Repolarisation
Positive ions are removed from the cell to return to resting membrane potential
Three main types of muscle
smooth, cardiac, skeletal
primary functions of skeletal muscle
voluntary movement and posture, develops force via contra ions
secondary functions of skeletal muscle
Organ support/protection, voluntary control over major openings, converts energy into heat (shivering)
individuals muscles cells
fibres
fascicles
bundles muscle fibres, bundled into muscles
tendons
muscles to bone
myofibrils
made of resting units called sacromere
sarcomere
Made of contractile proteins, actin and myosin
sarcolemma
cell membrane that wraps around muscle fibre
Transverse tubules
tube like extensions of the sarcolemma that conduct electrical signals
Sarcoplasmic reticulum (SR)
Membrane network associated with the T tubules at regular intervals
function of SR
stores calcium while muscle is relaxed and then realised for contraction
E-C coupling
pairing signalling event and mechanical event (contraction)
what proteins are used in the EC-coupling
DHPR, RyR, SERCA
What is DHPR
recieves signal and interacts with RyR
What is RyR
passive calcium pump that lets Ca out of the SR into the cell for contractions
What is SERCA
Active ca pump that pumps calcium back into the SR against the chemical gradient using ATP after a contraction
Cross bridge
when actin and myosin bind together in the presence of calcium to form a contraction
what are the 5 stages of the cross bridge cycle
attached, released, cocked, cross-bridge and power stroke
attached
just finished power stroke, cross bridge still present
released
atp binds to myosin in preparation for releasing energy, binding of ATP causes the cross bridge tp break
cocked
myosine burns ATp to make energy (ADP waste), energy is stored to get ready for the next contraction
corss-bridge state
calcium is present and bound to myofilamnet for the next contraction, myosin’s in head is energised by ATP energy and cross bridge is formed
powerstroke
corssbridge is formed, myosin’s uses stored energy to pull causing actin to slide and the muscle to contract
Fast fibres
large fibres, little blood supply, low fatigue resistance, fast response/peak tension
slow fibres
smaller fibres, lots of blood supply, fatigue resistant (generate energy while working) , slow tension peak time
skeletal force generation depends on?
number of fibres (recruitment) and frequency of stimulation (tetanus)
tetanus
frequency/speed of muscle stimulation
recruitment
number of fibres
