chap 9 muscular system III Flashcards
(21 cards)
motor unit
single motor neuron and all of muscle fibers it innervates
ATP
energy for muscle contraction comes from ATP
only small amounts are stored so new ATP must be continually synthesized
3 sources of new ATP within muscle fiber
creatine phosphate
anaerobic respiration
aerobic respiration
creatine phosphate (CP)
ATP can be sythesized when ADP reacts with creatine phosphate to form creatine and ATP
ADP+CP -> creatine + ATP
how long is ATP from creatine phosphate able to last
as long as the level of creatine phosphate is available in the cell
short time during intense exercise
how many seconds of sustained activity can CP synthesized ATP last?
8-15 seconds of sustained muscle activity
anaerobic respiration
if enery demands exceed oxygen supply to the cell, ATP is synthesized by anaerobic respiration and is used to provide energy for a short time during intense excercise
anaerobic respiration is… compared to aerobic
more rapid, but less efficient
where does anaerobic respiration occur
in the cytoplasm and begins with glycolysis
glycolysis
glucose (six carbon sugar) is split into 2 three carbon compounds called pyruvate
what happens to pyruvate after created?
goes through lactic acid fermentation to yield a net of 2 ATP molecules per glucose molecule
anaerobic respiration formula
C6H12O6 (glucose) –> pyruvate –> 2 lactic acid + 2 ATP + heat
what happens to waste products
lactic acid molecules diffuse out of the cell to blood plasma
liver cells convert
what do liver cells convert?
lactic acid + O2 –> eventual glucose molecule
aerobic respiration
used during resting conditions or during excercises such as long distance running
also begins with glycolysis in the cytoplasm
aerobic respiration is… compared to anaerobic respiration
more efficient but slower
what happens to the pyruvate during aerobic respiration
pyruvate are sent into the mitochondria where they go through the citric acid cycle (krebs cycle) and electron transport chain
how much ATP is created through aerobic respiration?
36-38 ATP molecules per glucose molecule
aerobic respiration formula
C6H12O6 (glucose) –> pyruvate +O2 –> CO2 + H20 + 38 ATP + heat
dealing with waste formula
CO2+H20 H2CO3 (carbonic acid) H+ + HCO3
oxygen debt
the amount of O2 needed (above that required for resting metabolism) to recover after vigorous exercise
myoglobin will attach to oxygen
for conversion of lactic acid to glucose in liver
for resting cells to replenish their ATP and CP synthesis
