Lecture 5 (Post-Natal Neuro Change

What is a Myofiber vs Myofibril?

• Myofiber: Multinucleated Muscle Cell

• Myofibril: Rod-Like Unit of Myofibers

What are the Stages of Myogenesis?

• 2 - 4 Weeks Gestation (Mesoderm → Myotome Cells)

• 4 - 5 Weeks Gestation (Myotome Cells → Myoblasts)

• 5 - 7 Weeks Gestation (Myoblasts → Myotubes)

• 20 Weeks Gestation (Myotubes → Myofibers)

What are Satellite Cells best for?

• Skeletal Muscle Cell Repair

What are the Muscle Fiber Types?

• Type I: Slow Twitch, Aerobic

• Type IIa: Fast Twitch, Aerobic

• Type IIb: Fast Twitch, Anaerobic

What is Muscle Power vs Dynamic Strength?

• Muscle Power: Largest Single Force In Shortest Time

• Dynamic Strength: Total Force Over Multiple Times

When is adult muscle contraction speed reached?

• 10 Years Old

Does muscle mass or muscle strength come first?

• Muscle Mass

How much mass is at birth vs adulthood?

• Birth: ¼ Body is Muscle Mass

• Adult: ½ Body is Muscle Mass

What is the best predictor of strength in adolescence?

• Height

What age ranges show the steadiest growth in Endurance vs Strength?

• Endurance: 5 - 14 Years

• Strength: 6 - 18 Years

What is the best form of exercise (w/ minimal damage) for children?

• Progressive Resistance Training (PRE)

  • Paired w/ Good Stretching Program

What are the Cartilage Types?

• Hyaline: Articular Joint Surfaces

• Fibrocartilage: Discs, Menisci, Tendons

• Elastic: Larynx, Ear, Epiglottis

What are the Bone Types?

• Cortical: Dense Outer Layer (80%)

• Cancellous: Spongy Inner Layer (20%)

What is Periosteum vs Endosteum?

• What function do they both share?

• Periosteum: Superficial To Cortical Bone (Not On Joints)

• Endosteum: Between Cortical & Cancellous Bone

• Shared Function: Bone Repair (Vascularized)

What is Intramembranous Ossification?

• When does it primary occur?

• Which bones is it primarily seen in?

• Mesenchyme Tissue → Bone Tissue

  • During: Late Embryo (8 Weeks Gestation) - Birth

  • Seen In: Cancellous Flat Bones (Skull, Hand, Clavicle)

What is Endochondral Ossification?

• When does it primary occur?

• Which bones is it primarily seen in?

• Hyaline Cartilage → Bone Tissue

  • During: Birth - Late Adulthood (30 Years)

  • Seen In: Cortical Long Bones (Femur, Humerus)

What are the different Ossification Centers?

• What type of ossification is involved in each?

• Is it responsible for length, width, or both?

• Primary: Diaphysis Formation (Middle)

  • Seen In: Intramembranous Ossification

    • For: Length & Width

• Secondary: Epiphysis Formation (Ends)

  • Seen In: Endochondral Ossification

    • For: Length Only

When do primary ossification centers appear?

• When are they in all the extremities?

• First Appearance: 7 - 8 Weeks Gestation

• In All Extremities: 12 Weeks Gestation

When do Diaphysis vs Epiphysis ossify?

• Diaphysis: Birth

• Epiphysis: Adulthood

Where do growth plates form?

• Between Epiphysis & Diaphysis

What is Appositional Growth?

• How does it occur?

• Diameter Growth

  • New Bone Placed Externally

  • Old Bone Absorbed Within

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