Hormones
Steroid vs Nonsteroid Hormones
Steroid -Lipid Soluble (Pass through membrane), Receptors found inside the cell, Derived from Cholesterol
Nonsteroid-non lipid solubile, receptors on cell membrane -> second messengers
All the parts of the muscle from biggest to smallest
Muscle->fasciculi-> muscle fiber-> muscle cells -> myofibrils -> myofilaments-> thick + thin
"Golden Standard" for Body Composition
DEXA Dual energy xray absorptiometry
Golgi Tendon Organ
Proprioceptor
Located Near Myotendinous Junction
Detects Tension
Inhibits Agonists
Hypertrophy vs Atrophy
Increase in Muscle Size =Increase in Muscle Strength
Decrease Muscle Size = Decrease Muscle Strength
Upregulation Vs Downregulation
Upregulation- Increasing the number of receptors in response low hormone levels
Downregulation- Decrease the number of receptors in response to high hormone levels
Type 1 vs Type 2 Fibers
Type 1
Slow Twitch, High Aerobic Endurance, Prolonged Periods of Exercise, Produce ATP From Fats and Carbs
Type 2
Fast Twitch, Highly Developed SR, Quickly Fatigue, ATP Anaerobically
Type 2a
Produce More Force, Short Intense Exercise
Type 2x
Everyday Activities, Short Explosive Sprints
ATP-PCR System
Anaerobic, Substrate Level Metabolism
Cells Contain Phosphocreatine PCr
ATP Yield: 1 mol ATP/ 1 mol PCr
Reassemble ATP
Phosphocreatine: ATP Recycling
Replenishes ATP during rest
Muscle Spindle Fibers
Sensitive to length and rate of change
Stretch Reflex Mechanism
Run Parallel to Normal Fibers
In the Belly of muscle
Autogenic Inhibition
Normal Intrinsic Inhibitory Mechanisms
-Golgi Tendon Organs
-Inhibit Muscle Contraction
-Prevent damage to bones and tendons
Training can decrease inhibitory impulses
-muscle can generate more force
What are the 5 Early Response Hormones
Epinephrine, Cortisol, Growth Hormone, Glucagon, and Insulin
Structural Proteins
Titin- Z Line -> M Line thick myofilament, anchors structure (contributes to contraction; tension)
Nebulin-anchoring protein for thin filament
Calculated from Heat Produced
1 cal= heat energy required to raise 1 g of water from 14.5-15.5 C
1,000cal=1kcal=1calories
Peripheral Nervous System
Connects Brain and Spinal Cord
Sensory and Motor Division
Sensory- To Brain Ex. Proprioceptors
Motor- From Brain (automatic and somatic)
Automatic- Fight or Flight (Sympathetic) and Rest (Parasympathetic)
Somatic- Skeletal Muscle Activity
Fiber Hypertrophy
More Myofibrils
More Actin, Myosin Filaments
More Sarcoplasm
More Connective Tissue
Resistance Training Increase Protein Synthesis
What are the Kidney Hormones and their Function
ADH- Increase Water Reabsorption
Aldosterone- Increase Na+ Retention
Sliding Filament
1.Resting Muscle Cell- ADP +Phosphate wait for calcium
2. Calcium attaches, release phosphate
3. Powerstroke -> ADP Release -> ATP Binds -> Head Detaches
4. New ADP and Phosphate (hydrolize)
5. Myosin Attach and Pulling Repeat
Glycolytic System
Anaerobic
ATP Yield: 2-3 mol ATP/1 mol substrate
Breakdown of glucose by glycolysis
Cons- low ATP yield, inefficient use of substrate
Lack of oxygen converts pyruvic acid to lactic acid and lactic acid impairs glycolysis
Lactate Threshold
Point at which blood lactate accumulation increase
Lactate Production Rate> Lactate Clearance Rate
Interaction of aerobic and anaerobic
Usually expressed by % of VO2max
Higher Lactate Threshold=Better Endurance Performance
Detraining
Leads to decrease in 1RM
Strength Loss Can Be Regained
New 1RM Exceeds Old 1RM
Regulation of Carbohydrate Metabolism During Exercise
Increase Intensity=
– Catecholamine release increase
– Glycogenolysis rate increase(liver, muscles)
– Muscle glycogen used before liver glycogen
Duration Increase= -More liver glycogen utilized
-Increase in muscle glucose uptake-> increase in liver glucose release
-more glycogen stores decrease in glucagon levels
10 Steps of Muscle Activation
1. Nerve sends message (action potential, depolarization)
2. Transfer message to muscle cell (acetylcholine at neuromuscular junction)
3. Muscle cells send message (action potential)
4. Calcium Release (movement of sodium through t tubules)
5. Calcium binds to troponin
6. tropomyosin moves out of the way
7. cross bridge formation
8. power stroke
9. cross bridge cycling
10. calcium reuptake back into SR
Krebs Cycle
Aerobic
1 Molecule of Glucose -> 2 Complete Kreb Cycles and Double ATP Yield
Produces NADH, FADH, and H+
Resting Membrane Potentional
-70mv = More Na+ outside of cell and lower K+ inside of the cell
Na+ Channels Closed wants to enter but cant, Electrical and Concentration Gradients
K+ Channels Open
K+ leaves cell
Offset by Na+ and K+ pumps
Fiber Type Alteration
Training Regimen May Not Outright Change Fiber Type, but
-Type 2 fibers become more oxidative w/ aerobic training
- Type 1 become more anaerobic
Conversion may be possible with high resistance training
Type 2a-> type 2x