Physiology Exam 8
Z-Line / Disc
Z to Z functional unit
I-band (light band)
ONLY THIN filament
A-Band (dark band)
Length of thick filament
Midpoint between Z's
ONLY THICK filament
Myosin binding site
Double helix chain
Ca2+ binding site
Lays over myosin sites on actin
Actin and ATP binding site
Golf club - like heads going in opposite directions on both ends
Thick myofilament (works alone)
Cross-Bridge (flexible; causes movement)
Skeletal Muscle Junction
site where the motor neuron synapses on the plasma membrane
site where acetylcholine is broken down after nerve cell impulses stop, closing the calcium channels in the transverse tubules.
Skeletal Muscle Twitch
Pattern of tension due to a single action potential
force from cross-bridge cycling
time between stimulation and tension development
-period in which binding is happening
Muscular contraction develops tension
Time in which Tension is removed from the muscle
-calcium moving into SR takes time, the channels close slowly.
What do we use ATP for in cross-bridge cycling (CBC)?
Unbinding; needed to unbind myosin from actin
Energizing the cross bridge
What do we use ATP for during Relaxation?
ATPase pumps move the calcium back into our sarcoplasmic reticulum (SR)
For every one calcium being moved you need one ATP.
What four sources do we get ATP from?
Substrate phosphorylation break apart creatine and phosphate.
Phosphate pairs with ADP, creating ONE ATP.
One step process; initial source
Increased cell osmolarity
Requires an absence of oxygen
1 glucose = 2 ATP
glucose comes from blood stream and glycogen stores in cell
Aerobic when using blood stream
Anaerobic when using glycogen; load up on carbs so plenty of sugars to make ATP from and don't have to use oxygen.
1 glucose = 2 ATP
Aerobic only (dependent on O2)
1st source: Glycolysis; producing pyruvate
other sources: fatty acids and amino acids
Source Krebs cycle (glycolysis)
Happens when able to STAY AEROBIC; therefore must avoid intense or prolonged activity.
generation of tension
opposed by load (your body + outside component)
Muscle held at same length (ex/holding object in front of you)
independent of the load
tension < load
Cross-bridge cycling is happening but does not have to shorten the muscle
happens first while building tension (latent stage)
dependent on the load
tension > load but not enough to lift
Length of the muscle changes.
No change in tension after movement begins, to assure smooth controlled movement
T>L muscle shortens
Muscle is able to partially relax between stimulus
Muscle does not relax at all between stimulus
Calcium V-gated channels are remaining open
Increase Load =
Degeneration of cells; wasting away
Usually happens when muscles are not being used or caused by disease
Increase in volume of an organ tissue
Usually due to exercise; building muscle
ability to sense stimuli arising within the body regarding position, motion and equilibrium
Smooth Muscle Locations
Muscle Spindles and Golgi Tendon Organs
Types of proprioceptors that provide input regarding muscle length and tension