EXSC 352 Exam 1 Review

Carbs, Fats, Proteins

4.1 kcal/gram, primary ATP substrate

9.4 kcals/gram, used for prolonged exercise

4.1 kcal/gram, used in lipogenesis

Liver (110 g), muscle (500 g), body fluids (15)

Subcutaneous (7,800 g), visceral (161 g), body fluids

Stored energy in small amounts until needed

Breakdown of ATP, ADP + Pi is energy

1. ATP-PCr system (Anaerobic)

2. Glycolytic system (Anaerobic)

3. Oxidative system (Aerobic)

3-15s, 1 mol ATP / 1 mol PCr

Anaerobic system

PCr + Creatine Kinase creates Creatine, Pi, and Free Energy

Free Energy + Pi + ADP = ATP

15s-2 min, 2-3 mol ATP / 1 mol substrate

Anaerobic System

10-12 enzymatic total reactions

Occurs all in the cytoplasm

ATP Yield: Glucose 2 ATP, Glycogen 3 ATP

Breakdown of glycogen into glucose

Used under 2 minutes max during exercise

Low ATP yield

Inefficient use of the substrate

Low O2 converts pyruvate to latic acid

Lactic acid impairs glycolysis causing muscle contraction

Allows muscle to contract with low O2

Short-term, high-intensity exercise when oxidative metabolism sustains energy

Rate limiting enzyme

Low ATP (Increased ADP) → Increase PFK activity

Increase ATP → Decrease PFK activity

Aerobic system

Can last for hours

ATP yield: 32-33 ATP / 1 glucose

ATP: 100+ ATP / 1 FFA

Krebs Cycle: Creation of ATP energy

1 Molecule of Glucose → 2 acetyl-CoA

2 acetyl-CoA → 2 GTP → 2 ATP

ATP Yield: 1 glucose → 32 ATP / 1 glycogen → 33 ATP

Glycolysis = +2 ( or +3) ATP

GTP (Transports Pi to ADP) = +2 ATP

10 NADH = +25 ATP

2 FADH = + 3 ATP

Lipids go through Beta-Oxidation and is added to the Acetyl-CoA during Krebs

H+ and electrons are carried to ETC via NADH and FADH molecules

H+ travel down the chain combining with O2

Electrons and O2 create ATP

NADH: 2.5 ATP

FADH: 1.5 ATP

Fuel for exercise

1. Cytoplasm

2. Transported to another cell

3. Liver

Taken up by mitochondria of the same muscle and is oxidized

Transported by MCP transporters and is oxidated there

Recirculated into the liver to be converted back into pyruvate, then to glucose (via gluconeogenesis)

Volume of both CO2 and O2 that is produced

RER = VCO2 / VO2

Gluconeogenesis is produced at an RER of <0.7

Can be inaccurate when lactate buildup increases over the CO2 exhalation

Inability to maintain required power output at a given intensity

1. Inadequate energy delivery

2. Accumulation of by-product

3. Failure of muscle contraction

4. Altered neural control

Rest

Phosphorus accumulation

PCr gets depleted faster than ATP

Limited and gets depleted quickly

Depletes faster at a higher intensity

FFA Oxidation is slow

Pi: From PCr and ATP

Heat from sweat

Carbs from heat

Lactic Acid from glycolysis

Measurement of Calories over time, good for RMR measurements

It is expensive and slow, heat can be added by exercising, sweat can cause errors

Failure of muscle activation (Cramp)

Stress from exercise taxing the CNS

Discomfort of fatigue

Estimate of total energy expenditure via O2 and CO2 production, accurate only with a steady-state of oxidative metabolism

Old methods are accurate but slow

Skeletal, Smooth, Cardiac

Surrounded by Epimysium

Made up of fasciculi

Surrounded by perimysium

Made up of muscle fibers

Surrounded by endomysium

Made of myofibrils (sarcomeres)

Fused with the tendon that conducts the Action Potential (AP), it maintains the pH levels and transports nutrients

They promote muscle growth and development

Helps with injury, immobilization, and training

Serves as cytoplasm of the muscle cell

Unique Features: Glycogen storage and myoglobin

Serves as extension of the Cell membrane

Carries the AP deeper into the muscle fibers

Ca2+ storage

Muscle → Fasciculi → muscle fiber → myofibril

Contains over +100K per muscle fiber

Basic contractile element of the skeletal muscle

Be able to label the following:

A-band → Dark stripes

I-Band → Light stripes

H-Zone → middle of the A-Band

M-Line → Middle of H-Zone

Actin, Myosin, Titan

Two intertwined filaments

Contains Globular Heads

→ Interacts with actin filaments to contract

Uses Titin as stabilizer

Composed of three proteins:

1. Actin - the myosin-binding site

2. Tropomyosin - Convers active sites at rest

3. Troponin → Moves tropomyosin

Anchored at Z-Disk

Uses nebulin to keep equal space constant between actin

Acts as a spring

1. Extends from Z-disk to M-band

2. Calcium bind to titan, increasing muscle force

Stabilizes sarcomeres and centers myosin

Prevents overstretching of the muscle

Consists of an Alpha motor-neuron + all fibers around it

More active motor units = stronger contraction

Synapses between Alpha Motor-neurons and muscle fibers

Serves as a Communication site

1. AP starts at the brain

2. AP arrives at Axon Terminal, releases ACh

3. ACh crosses synapse and binds to ACh receptor on cell membrane

4. AP travels down the cell membrane and T-tubules

5. Triggers Calcium release from the Sarcoplasmic reticulum

6. Calcium activates actin-myosin contraction

Relaxed:

1. No interaction occurs at the binding site

2. Myofilaments overlap a bit

Contraction:

1. Myosin head pulls actin to the center of sarcomere (Powe rstroke)

2. Filaments slide past each other

3. Everything shortens

1. Myosin detaches

2. Myosin goes back to original position and moves down to another active site

Process continues until Z-Disk reaches myosin filaments or AP stops

1. AP Stops

2. Calcium is pumped back into sarcoplasmic reticulum

Type 1 and Type 2

About 50% of fibers in the muscle

Slow twitch muscle

<300 fibers due to smaller neuron

Fast twitch

2 types

1. Type 2a (25%)

2. Type 2x (25%)

>300 due to larger neuron

Type 2x → Fast then rapid decline

Type 2a → Medium force then rapid decline

Type 1 → Slow build, slow decline

Method for altering force production

Less force = Less motor units

More force = More motor units

Genetics, training , aging, and any possible influence from the nervous system

Type 2 fatigue quickly

Type 2a → Short, intense endurance

Type 2x → Short explosive sprints

Type 1 is used in endurance training

Muscle produce a lot of force but don’t change length

Joint angle doesn’t change

No sliding filaments

Muscle produces force and changes length

Joint movement occurs

Optimal sarcomere length equals optimal overlap

If it is too short or over stretched, then little to no force is developed

Central nervous system

Contains Brain and spinal cord

Sensory (Afferent) → Incoming

Motor (Efferent) → Outgoin

1. Somatic: Voluntary

2. Autonomic: Involuntary

   1. Sympathetic

   2. Parasympathetic:

3 regions

1. Cell body → Nucleus

2. Dendrites → Receives information

3. Axon → Sends signals

Send and receives different signals

Maintains the resting membrane potential of the neuron and creates the concentration difference in the cell

3 Ka+ in

2 Ca2+ out

When the Graded potential either excites or inhibits the neuron into an Action potential

Needs to cross the All-Or-Nothing Complex (-50mV)

Neuron is unable to respond to another stimulus

Neuron only responds to a very strong stimulus

ACh stimulates skeletal muscle contraction, mediates the parasympathetic NS effects

Norepinephrine mediates sympathetic NS effect

Endorphins

Frontal → Motor control, general thought

Temporal → auditory processing and interpretation

Parietal → General sensory processing and interpretation

Occipital → Visual processing and interpretation

Insular → Emotion and self-perception

Frontal Lobe, Basal Ganglia, and Parietal Lobe

Sensory and Motor

1. Mechanoreceptors → Pressure, touch, vibration, stretch

2. Thermoreceptors → Heat

3. Nociceptors → Pain

4. Photoreceptors → Light

5. Chemoreceptors → Chemical stimulus

Stimulates skeletal muscle

Regulates visceral muscle (smooth muscle)

Fight, Flight, Fawn, Freeze

Rest and Digest