NASM Chapter 5: Nervous, Muscular, Skeletal Systems

What is the nervous system?

command center for the body
controls movement → internal organ functions

What is the nervous system made of?

cell body, axions, dendrites

What’s the primary role of the nervous system?

sensory input → integration → motor output

What are the integral parts of the nervous system?

brian and spinal chord

processes information

What is the peripheral nervous system?

cranial nerves (12 pairs) + spinal nerves (31 pairs)

connects CNS to whole body

What are the subdivisions of the Peripheral nervous system?

sensory (afferent): body → CNS

Motor (efferent): CNS - > body
autonomic = involuntary (organs)

somatic = voluntary muscle control

What is the two parts of the autonomic nervous system?

• sympathetic → fight or flight → increases HR, breathing, alertnes

• parasympathetic → rest & digest : calms the body

Explain sensory motor pathways

• Stimulus (heat, cold etc.) → receptor

• Info carried via afferent / sensory nerves

• processed by interneruons in CNS

• response sent via efferent / motor nerves

• reflexes (stretch / withdraw reflexes) skip conscious brain input

What is a mechanoreceptor & what does it do?

movement specific sensory organ
detects pressure + touch

located in muscles, ligaments, tendons and joints

what are the types of mechanoreceptors?

Muscle Spindles

Golgi Tendon Organ
Joint Receptors

What is the function of muscle spindles?

detects role + length, triggers stretch reflex

What is the function of Golgi Tendon Organs?

detects tension / inhibits contraction to prevent injury

What is the function of Joint Receptors?

detects pressure, extreme position & helps prevent joint damage

What is proprioception?

• body’s ability to sense position and movement

• like an “internal GPS”

• it is trainable → improves balance, posture & coordination

What are the motor learning stages & their functions?

cognitive = learning the skill
associative = improving, fewer mistakes
autonomous = mastery of skill

What is the purpose of the skeletal system?

provides feeback for human movement & supports physical vitality

shapes body & gives structure

protects internal organs
acts as a level for the muscles
produces blood cells in bone marrow

stores minerals (calcium + phosphate)

What are the skeletal divisions?

axial
appendicular

What does the Axial skeleton contain and what is it’s function?

• skull, rib cage, vertebrae column (roughly 80 bones)

• protects CNS and vital organs

What does the appendicular skeleton contain and what is it’s funciton?

• arms, legs, pelvic and shoulder girdles

• enables movement and locomotion

How many bones do humans have?

206

How many bones are used in voluntary movement?

around 177

How many joints do we have?

250-350

How does bone continuously re-model?

osteoclasts → breaks down old bone tissue

osteoblasts → builds new bone tissue

What is wolffs law?

bones adapt to the load they’re exposed to

more stress = stronger bones (up to a point)

How many types of bones exist and what are they

5
Long, short, flat, irregular, sesamoid

What is a long bone? Give examples

• cylindrical, act as levers, strong & weight bearing

  • ex: femur, humorous, tibia

What is a short bone? give examples

• cube-shaped, absorb shock

  • carpals (wrist), tarsal's (ankle)

What is a flat bone? give examples

• thin, protetive, broad muscle attatchment

• scapula, ribs, sternum

What is a irregular bone? give examples

• complex shape, specialized function

• vertebrae, pelvis

What is a sesamoid bone? give examples

• embedded in tendons, reduce friction

  • patella (knee cap)

What is the epiphysis part of a long bone?

• ends of the bone

• site of red marrow & growth

What is the diaphysis part of a long bone?

• bone shaft

• strong structure for weight support

What is the Epihysial plate?

growth zone (closes after puberty

What is the medullary cavity?

houses marrow for blood cell production

What is a periosteum?

• the outer layer of a long bone

• achors for tendons & ligaments

What is articular cartilage?

smooth covering to reduce joint friction

What are bone markings?

serve as the attachment points & leverage sites for muscles, tendons and ligaments

How many types of bone markings are there and what are their names?

7

fossa, sulcus, condyle, epicondyle, tubercle, troncher, process

What is the function of the spine?

protects spinal chord while allowing movement & flexibility

What are the five regions of the spine?

cervical, thoracic, lumbar, sacrum, coccyx

Explain the cervical region of the spine?

• C1-C7

• 7 vertebrae

• function: supports and moves the head

Explain the Thoracic region of the spine

• T1-T12

• 12 vertebrae

• anchors ribs

• protects thoracic organs

Explain the lumbar region of the spine

• L1-L5

• 5 vertebrae

• bears most body weight

Explain the sacrum region of the spine

• S1-S5

• 5 vertebrae (fused)

• transfers weight to pelvis

Explain the coccyx region of the spine

• 3-5 vertebrae (fused)

• tailbone, vestigial support

What is “breakfast, lunch and dinner” in relation to the spine?

• 7 cervical = breakfast @ 7 → concave

• 12 thoracic = lunch @ 12 → convex

• 5 lumbar = dinner @ 5 → concave

• ^^ all combine to form “neutral spine” ^^

What are joints?

pivot points that enable the skeleton to move

what is osteokinematics?

• movement of bones

• ex: flexion / extension

what is arthrokinematics? What are their types?

movement at joint surface

roll: one bone rolls across another, femur rolling over tibia during squat

slide / glide: one bones lsides across another, tibia sliding on femur during knee extension

spin: one bone rotates around a stationary partne, radius spinning on humerous during pronation / supination

What are synovial joints?

• surrounded by a capsule, filled with synovial fluid

• allow free motion

• roughly 80% of all joints

What are the types of Synovial joints and their functions?

gliding: minmal moement; slides… carpals in wrist

condyloid: movement in one direction with slight lateral motion…. fingers

hinge: uniaxial; flexion / extension only… elbow & ankle

saddle: biaxxial; thumb only

pivot: rotational movement around an axis… radiovulnar joint

pivot and socket: triaxial, greatest range of motion… shoulder and hip

What are Non-Synovial joints?

• no capsule or fluid

• little to no movement

• sutures in skull

What is the function of ligaments?

• provide joint stability / feedback

• have poor vasularity, meaning they heal slowly and adapt gradually to stress

• connect bone to bone

• give stability (static and dynamic)

• Sensory feedback for join position (proprioception)

What are ligaments made out of?

Collagen: provide tensile strenght, provide pulling foreces

Elastain (variable): elastic recoil, handles twisting & flexibility

What are growth plates called? Where are they located and what do they do?

epiphyseal plates
at the ends of long bones

• responsible for longitudinal growth during adolescense

• close after puberty (18F & 20M)

How many types of joints are there?

6

What are the joint types and ideal training methods?

Bail and socket: train full ROM under control

Hinge: load management critical (knees/elbows)

Pivot: control rotational forces (pronation drills)

Gliding / Condyloid: improve mobility through activation

Saddle: thumb health for dexterity

LIgaments; emphasize joint friendly mechanics; avoid overstrain

What’s the main function of the muscular system?

• To connect the nervous system to the skeletal system, enabling movement through force production

  • skeletal muscle → cardiac muscle → smooth muscle

How does muscle contraction work?

involves an electrical signal that creates a chemical reaction which then moves the muscle in the desired way

What is the structural hierarchy of the muscle? What are each components, connective tissue, and function?

Protein Filaments: actin & myosin, none, slide past eachother to produce movement

Sub-Cellular: myofibril, none, contain sarcomeres (contractile unites)

Cells: muscle fiber, endomysium, contracts via myofibrils

Bundles: fascicle, perimysium, groups fibers for specific function

Whole Muscle: Muscle, Epinysium, encloses and protects entire muscle

What are fascia?

connective tissue sheaths `

What are tendons?

connect muscle to bones

What are ligaments

connects bone to bone

What’s a strain vs a sprain?

strain is a muscle injury

sprain is a ligament injury

What are the components of a muscle cell?

Sarcolemma: muscle fiber membrane (conducts action potentials)

Sarcoplasm: cytoplasm of muscle cell, hold glycogen, myoglobin and mitochondria

Myofibrils: cylindrical structures housing myosin & actin

Sarcomere: contractile unit, bordered by z-lines

Mitochondria: produce ATP for energy

Myoglobin: stores oxygen in the muscle cells

What is a neuromuscular junction?

electrical signals (action potentials) from motor neurons trigger MF conraction

ACH: acetylcholine is released across the synaptic cleft to initiate muscle action

Explain the Sliding Filament Theory:

myosin heads pull actin filaments inward, shortening sarcormers & contracting muscle fibers

What is the ex-citation-contraction coupling process?

1. ACH released at synapse

2. Action Potential travels down T-tubules

3. Sarcoplasmic reticulum releases Ca^2

4. Calcium binds to troponin, moves tropopyosin, exposing binding sites

5. Myosin bonds to actin → Power stroke (ATP is used)

6. Sarcomere shortens = contraction

7. Signal steps → calcium reabsorbed → muscle relaxes

8. “No calcium, no contraction, no ACH, no signal”

9. “All or nothing principle”

What are the motor units and their functions?

Motor Neuron + Muscle Fiber: functional contractile unit of the muscle

Small Motor Unit: fire control (eyes, hands)

Large Motor Unit: Gross Power (Quads + glutes)

A muscle fiber fully contracts or not at all, depending on what?

• number of motor units recruited

• Type (size/speed) of motor units

What are the types of muscle fibers?

Slow twitch
Fast Twitch Intermediate

Fast Twitch