Use of skeletal muscles
and transfer of energy
From the whole
animal to the cellular level
TRANSFER OF ENERGY
Energy input
Food energy
Energy output
Metabolic
pool
in body
Internal work
External work
Energy storage
Thermal energy
(heat)
Calorie:
The amount of heat required to raise the
temperature of one gram of water from 14.5°C
to 15.5°C.
1 calorie = 4.184 joules.
A good example of a structure and function
relationship is skeletal muscle
Where does the ATP
come from?
Food
O2
ATP
Energy harnessed as ATP,
the common energy currency
for the body
ATP
ATP
Muscle contraction
Partly used to maintain
body temperature in
endotherms
Explosive release
of energy as heat
Excess heat
eliminated to the
environment
The body must regulate the level of ATP since
you only want it around when you need it as
it will break down and make heat.
Regulation of ATP production comes about
by controlling production through graded reactions
inside cells.
The breaking of these
chemical bonds will
produce heat.
The energy stored in
the chemical bonds is
transferred to heat.
Glucose is broken down
to make ATP
Most cells in your body.
Most ATP is produced here in
the chemical reactions.
This ATP can be used to allow
muscle cells to function.
Mitochondria are the power house
of the cell.
Energy within the cells used to drive the tissue- to organ- to system.
Energy transfer from food (fuel) to ATP in cells that can then be used to make proteins
or used to contract muscles or to keep cells working properly by transporting items
for the cell (Na+ sodium & K+ potassium).
*
Food
O2
ATP
Energy harnessed as ATP,
the common energy currency
for the body
ATP
ATP
Muscle contraction
Partly used to maintain
body temperature in
endotherms
Explosive release
of energy as heat
Excess heat
eliminated to the
environment
*
Getting rid of the heat from
muscle contraction and breaking
chemical bonds to make the ATP
is a problem in exercise.
Many chemical reaction in our body give off heat.
Heat
Building a compound:
A+B
C
Heat
Breaking down a compound:
A
B+C
Direction of arrows denotes direction of heat transfer
Snowball
Radiation
Conduction
Convection
Evaporation
Heating pad
1
2
Liquid
converted
to gaseous
vapor
Convection
current
3
4
Transfer heat from the hot body to cool water
For work from muscles:
Energy comes from food or body reserves (fat, protein, glycogen).
Food or body reserves provides ATP through a series of
chemical reactions inside cells.
(Energy transfer from chemical bonds to ATP + heat)
ATP used for muscles to function. Sliding units of muscle.
(Energy transfer from muscles to external work + heat)
Muscle fatigue: This is a study of human performance.
Task dependant (type of muscle)
Before we can study this one has to know how nerves and
muscles work for performing a task
Muscle fatigue: This is a study of human performance.
Task dependant (type of muscle)
Before we can study this one has to know how nerves and
muscles work for performing a task
nerve
muscle
Terminal button
Muscle fibers
Axon terminals
Presynaptic axon
terminal
Voltage-gated
Ca2+ channel
Synaptic knob
Ca2+
Neurotransmitter
molecule
Synaptic vesicle
Synaptic cleft
Subsynaptic
membrane
Chemically-gated
ion channel for
Na+, K+, or Cl2
Receptor for
neurotransmitter
Postsynaptic
Muscleneuron
muscle
Neurotransmitter
Ion movement results in electrical
change across cell membrane
Na+
Receptor on cell
K+
Muscle cell
3 Na+
ATP
Pump ions back across
membrane (needs ATP)
2 K+
Axon of motor neuron
Myelin sheath
Action potential
propagation
in motor neuron
Axon terminal
Terminal button
Vesicle of acetylcholine
Acetylcholine
receptor site
Voltage-gated
calcium channel
Acetylcholinesterase
Plasma membrane
of muscle fiber
Action potential
propagation
in muscle fiber
Ca2+
Na+
Voltage-gated
Na+ channel
K+
Na+
Chemically gated
cation channel
Motor end plate
Contractile elements within muscle fiber
Electrical change results in
a process within the cell to
cause the muscle to contract.
(calcium ion movement)
Ca2+ is pumped back
Takes ATP
Need fine control:
Pick up a piece of paper or a rock.
To increase muscle contraction:
1. Increase muscle cell activity
(increase nerve activity
by # of electrical events)
2. Increase the # of muscle units
(increase # of nerves used)
Muscle fatigue:
1. The nerve
nerve
muscle
2. At the nerve to muscle
3. At the muscle level
Muscle fatigue:
1. The nerve
ATP needed here to keep ions (Na+ & K+) normal
nerve
2. At the nerve to muscle
ATP needed here to keep vesicles cycling
muscle
3. At the muscle level
ATP needed here to keep muscle working
Note: ATP is made inside the cells that require it.
• Grip strength 1st
-1 second series of contractions
- measure the time it takes to fatigue 50%
- graph each others data
- discussion of results
1. measures of forearm circumference and
relate to time (muscle mass, bone thicknessdistorts results)
2. did they just eat, tired, sleep, etc..
(could have a box to check off on chart)
Name
Time to 50%
Forearm (cm)
Tired, food, etc Other factors
• Pinch strength
– Same idea as the grip strength
– Can graph on same graph (left and right
sides)
Name
Right arm
50%
Left Arm
50%
Right
Finger 50%
Left
Finger 50%
Tired, food,
etc
Other factors
Heart rate changes:
Decrease HR
- decrease breathing rate just sitting still (not to slow that you pass out)
- cold rag on back of the neck (not on face - some people
have strong diving responses and can pass out. KIDS !!!)
Increase HR
- increase breathing rate just sitting still (not to fast that you pass out)
- measure before and after running in place (5 min)
Graph data with variable used. Compare with class and have discussion.
- Reasons for the changes.
- Reasons for differences in students for same test.
- List what other types of experiments could be done.
Why does HR go up or down?
• Oxygen to tissues for making ATP for the
muscles to work.
• How does oxygen get to the tissues?
• Heart is a pump for blood. The blood
carries the oxygen. So HR goes up to
bring the blood with its oxygen to the
muscle.
Heart
pumps
the blood
Acknowledgements
Robin Cooper
(UK- Biology)
Terry Williams
(UK- Biology, Secondary science Ed.)
Richard Cooper
(6th- Morton Middle)
Ann Cooper
(10th- Lafayette High, past Morton student)
Jan. 2007
Folder: Human Physiology with Vernier
Inside folder find---17a Grip Strength Fatigue
Note: do not hold on to hand grip place when
conducting finger fatigue experiment.
Hand Grip
Finger Grip
Find program: 27 Heart Rate & Fitness
Note: Watch the direction of arrows on hand device and monitor.
Need to be in the same direction and keep hands
between the monitor.
NAME OF PROGRAM: 27 Heart Rate & Fitness
1st page should look like this
1sec hand grip contractions
Do it for 30 sec to match 50% fatigue
To copy pictures:
Go to “select all” and then “copy” and “paste”
Can be put directly into ppt or any graphic program