Understanding Synaptic Morphology

• Aerobic exercise: relies on oxygen for energy production, increases oxygen consumption, primary energy sources are carbohydrates and fats, aerobic metabolism occurs in mitochondria
• Increased heart rate and stroke volume: enhances cardiac output, oxygen-rich blood delivery
• Respiratory rate and oxygen delivery: facilitates oxygen exchange and carbon dioxide removal
• Sustained energy output: moderate-intensity, long-duration activities, glycogen and fatty acids utilized
• Recovery period: gradual return to baseline, EPOC (excess post-exercise oxygen consumption) repays oxygen debt, energy stores are replenished
• Anaerobic exercise: high-intensity, short-duration efforts, limited oxygen availability, glycolysis occurs without oxygen, producing lactate as a byproduct
• Increased heart rate and breathing rate: to meet oxygen demands
• ATP from phosphocreatine: rapid energy source for short bursts of activity
• Lactic acid production: disruption of the energy balance and muscle fatigue
• Lactate clearance: post-exercise period, lactate is cleared, converted to pyruvate, or used for energy
• Replenishment of ATP and phosphocreatine: occurs during recovery, utilizing oxygen-dependent processes
• Restoration of pH balance: disrupted by lactic acid during anaerobic activity, the body works to restore the balance
• EPOC: less pronounced but still occurs, metabolic rate remains elevated during recovery

Comparison of skeletal, cardiac, and smooth muscle:

• Skeletal muscle: attached to bones, striated appearance, voluntary control, located in the somatic nervous system

• Cardiac muscle: forms heart walls, striated appearance, intercalated discs, involuntary control, located in the autonomic nervous system

• Smooth muscle: found in internal organs, non-striated appearance, spindle-shaped cells, involuntary control, regulated by the autonomic nervous system and hormones

• Muscle fiber structure: skeletal muscle: long, multinucleated fibers with sarcomeres; cardiac muscle: branched cells with a single nucleus and intercalated discs; smooth muscle: spindle-shaped cells without sarcomeres

• Neuromuscular junction: skeletal muscle: acetylcholine is the neurotransmitter with conscious control; cardiac muscle: less defined, acetylcholine and norepinephrine are neurotransmitters with autonomic control; smooth muscle: less defined, neurotransmitters are varied with autonomic control and hormonal regulation

• Production of action potentials: skeletal muscle: voluntary control, action potentials generated by somatic motor neurons; cardiac muscle: involuntary control, action potentials generated by pacemaker cells; smooth muscle: involuntary control, action potentials generated by autonomic nerves and hormones.

• Threshold and Action Potential: If membrane potential reaches a certain threshold, more voltage-gated sodium channels open, triggering a rapid influx of sodium ions and creating a spike called the action potential. Repolarization follows, restoring membrane potential with the help of voltage-gated potassium channels and the sodium-potassium pump.

• Muscle Cell Excitation-Contraction Coupling: At the neuromuscular junction, acetylcholine release causes depolarization and action potential propagation through T-tubules, stimulating the sarcoplasmic reticulum to release calcium. Calcium binds to troponin, causing a conformational change and actin-myosin binding, leading to contraction. Calcium is then pumped back into the sarcoplasmic reticulum, removing calcium and preventing further contraction.

• Skeletal Muscle: Attached to bones, responsible for voluntary body movements, and under conscious control.

• Smooth Muscle: Found in internal organs and structures, responsible for involuntary contractions, and mostly under autonomic nervous system control.

• Cardiac Muscle: Part of the heart, contracts rhythmically, and involuntarily, with some unique properties that allow it to generate its own rhythmic contractions.

• Sarcomere: Structural unit of muscle fibers, composed of actin and myosin filaments, Z-discs, I-band, A-band, and H-zone.

• Actin Filaments: Thin filament of globular actin monomers, anchored to Z-discs, and extends towards the center of the sarcomere.

• Myosin Filaments: Thick filament of myosin molecules, located in the center of the sarcomere, and overlaps with actin filaments.

• Z-Disc (Z-Line): Protein structure that bisects the sarcomere, acts as attachment points for thin actin filaments, and helps define the boundaries of the sarcomere.

• I-Band (Isotropic Band): Region of the sarcomere containing only thin actin filaments and extending from the Z-disc towards the center of the sarcomere.

• A-Band (Anisotropic Band): Central region of the sarcomere that contains thick myosin filaments and both overlapping actin and myosin filaments.

• H-Zone: Region within the A-band where only myosin filaments are present, and there is no overlap with actin filaments.

• M-Line: Protein structure at the center of the H-zone that helps stabilize and align myosin filaments.

• Titin: Giant protein spanning the Z-disc to the M-line, providing structural support and elasticity to the sarcomere.

• Aerobic exercise: relies on oxygen for energy production, increases oxygen consumption, primary energy sources are carbohydrates and fats, aerobic metabolism occurs in mitochondria

• Increased heart rate and stroke volume: enhances cardiac output, oxygen-rich blood delivery

• Respiratory rate and oxygen delivery: facilitates oxygen exchange and carbon dioxide removal

• Sustained energy output: moderate-intensity, long-duration activities, glycogen and fatty acids utilized

• Recovery period: gradual return to baseline, EPOC (excess post-exercise oxygen consumption) repays oxygen debt, energy stores are replenished

• Anaerobic exercise: high-intensity, short-duration efforts, limited oxygen availability, glycolysis occurs without oxygen, producing lactate as a byproduct

• Increased heart rate and breathing rate: to meet oxygen demands

• ATP from phosphocreatine: rapid energy source for short bursts of activity

• Lactic acid production: disruption of the energy balance and muscle fatigue

• Lactate clearance: post-exercise period, lactate is cleared, converted to pyruvate, or used for energy

• Replenishment of ATP and phosphocreatine: occurs during recovery, utilizing oxygen-dependent processes

• Restoration of pH balance: disrupted by lactic acid during anaerobic activity, the body works to restore the balance

• EPOC: less pronounced but still occurs, metabolic rate remains elevated during recovery

Comparison of skeletal, cardiac, and smooth muscle:

• Skeletal muscle: attached to bones, striated appearance, voluntary control, located in the somatic nervous system
• Cardiac muscle: forms heart walls, striated appearance, intercalated discs, involuntary control, located in the autonomic nervous system
• Smooth muscle: found in internal organs, non-striated appearance, spindle-shaped cells, involuntary control, regulated by the autonomic nervous system and hormones
• Muscle fiber structure: skeletal muscle: long, multinucleated fibers with sarcomeres; cardiac muscle: branched cells with a single nucleus and intercalated discs; smooth muscle: spindle-shaped cells without sarcomeres
• Neuromuscular junction: skeletal muscle: acetylcholine is the neurotransmitter with conscious control; cardiac muscle: less defined, acetylcholine and norepinephrine are neurotransmitters with autonomic control; smooth muscle: less defined, neurotransmitters are varied with autonomic control and hormonal regulation
• Production of action potentials: skeletal muscle: voluntary control, action potentials generated by somatic motor neurons; cardiac muscle: involuntary control, action potentials generated by pacemaker cells; smooth muscle: involuntary control, action potentials generated by autonomic nerves and hormones.