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BIOL1040 > MODULE 3: Support and Movement > Flashcards

MODULE 3: Support and Movement Flashcards

1
Q

Muscle Types

A

skeletal, smooth, caridac

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2
Q

Smooth Muscle

A
  • found within walls of gastrointestinal tract
  • facilitates digestion via contraction
  • non striated and parallel
  • also found in blood vessels, lymphatic vessels, urinary bladder, uterus, male and female reproductive tracts, respiratory tract, skin and iris
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3
Q

Cardiac Muscle

A
  • only found in contractile walls of heart
  • striated and branched
  • contractile properties
  • muscle fibres interconnect at intercalated sidk
  • allows electrical signal to pass from one cell to another
  • helps syncronise heart muscle contraction
  • uni-nucleate
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4
Q

Skeletal Muscle

A
  • makes up 40-50% of body mass
  • striated and stripes
  • sarcomeres shorten suring contraction
  • muscle cells/fibres are long and multi-nucleate
  • multiple nuclei allow repair and growth all the way along fubre
  • controlled by somatic system
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5
Q

Function and Structure of Skeletal Muscle

A
  • 320 different skeletal muscles in humans x 2 sides
  • muscles used for postural, fine motor and gross motor control

Contractility: ability to shorten and thicken to develop tension
Excitability: ability to respond to appropriate stimuli
Extensibility: ability to be stretched without damage
Elasticity: ability to store energy and recoil to resting length

  • connective tissue dispersed throughout fibre
  • muscle is made up of a large number of fasicles (bundles) of fibres surrounded by connective tissue
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6
Q

Sarcomeres

A
  • contains a series of thick and thin filaments that move in relation to each other
  • form adjacent myofibrils line up which gives striated appearance
  • thin filaments (actin) attach at Z-line
  • thick filaments (myosin) anchor at M line in centre of sarcomere
  • Z line to Z line = sarcomere
  • at rest, actin and myosin slightly overlap
  • contraction = more overlap
  • elastic filament: titin anchors myosin to z line and contributes passive force
  • myosin and actin are fine protein strands
  • heads on myosin have actin binding sites to pull actin for contraction

draw diagram

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7
Q

Cross Bridge

A

linked myosin head and actin filaments

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8
Q

Power Stroke

A

attachment and pull producing force

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9
Q

Connective Tissue

A

Endomysium: surrounds each muscle fibre
Epimysium: fibrous tissue that surrounds skeletal muscle
Perimysium: groups muscle fibres into a fasicle

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10
Q

The Motor Unit

A
  • connection b/w nervous system and skeletal muscle
  • smallest functional unit in musculoskeletal system
  • motor unit = 1 motorneuron, its motor axon and all muscle fibres it innervates
  • action potential generated in motor neuron generates an action potential in motor units muscle fibres
  • force altered by number and discharge rate of motor units and contractile properties of muscle fibres
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11
Q

Muscle shapes

A
  • affects action of muscle
  • circular muscles can close an opening
  • long muscles are better at controlling movement over joints that have a large range of motion
  • shorter/wider muscles are better at generating larger forces over small range of motion
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12
Q

Cross-Sectional Area

A
  • greatest predictor of force is physiological cross sectional area

PSCA = (muscle volume) / (fibre length)

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13
Q

Sarcomere Length and Myofibrils

A
  • inside each muscle fibre is a bundle of myofibrils that lie in parallel
  • contractile filaments that convert the electrical signal (AP) initiated in the nervous system to muscle force are within myofibril
  • a series of sarcomeres make up each myofibril
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14
Q

Muscle Tendon Unit

A 
Contractile Component (CC)
- muscle fibres, actin and myosin cross bridges

Series Elastic Component (SEC)
- intracellular titin, tendon

Parallel Elastic Component (PEC)
- connective tissue, epimysium, perimysium, endomysium and passive cross bridge connections

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15
Q

Length Tension Relationship

A
  • Sarcomere length influences force that can be developed

- optimal sarcomere length is 80-120% of resting sarcomere length

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16
Q

Discharge Rate

A
  • force influenced by discharge rate of active motor units
  • slow twitch: less force and longer duration
  • fast twitch: more force and shorter duration
  • easier to have summation of slow twitch
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17
Q

Axial Skeleton

A
  • related to head and trunk of body
  • 80 bones
  • skull, rib cage,vertebral column
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18
Q

Appendicular

A
  • relates to limbs
  • 126 bones
  • shoulder girdle, arm, upper limb, hands
  • pelvic girdle
  • lower limb, foot
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19
Q

Sagital / Parasagital

A
  • divides body into left and right

- parallel w/ sagital (left and right but not equal)

20
Q

Coronal

A

divided body into posterior and anterior

21
Q

Sagital Plane

A

Transverse: divides into cranial and caudal (superior and inferior)

Flexion: decrease joint angle

Extension: increase joint angle

22
Q

Dorsiflexion

A

raise foot

23
Q

Plantarflexion

A

lower foot

24
Q

Abduction / Adduction

A

away from body / towards body

25
Q

Supination / Pronation

A

palm up / palm down

26
Q

Lateral / Medial

A

external rotation / internal rotation

27
Q

Joint Structures

A

Fibrous:

  • contain fibrous connective tissue
  • some cannot move (skull)
  • some allow a little movement (depends on length of connective tissue)

Cartilaginous:

  • contain cartilage
  • cushions force
  • allow little bit of movement

Synovial:

  • have a space b/w adjoining bones
  • synovial capacity filled with fluid
  • largest range of motion
28
Q

Synovial Joints

A

Hinge:

  • restrict movement to a single plane
  • b/w head and humerus, ulna, knee, fingers

Ball & Socket:

  • enable arms and legs to rotate and move in external planes
  • shoulder, hip

Pivot:

  • rotating forearm at elbow
  • head side to side
29
Q

Antagonist Muscle Pairs

A
  • muscles apply opposing force to perform joint movement (bicep and tricep)
30
Q

Agonist Muscle Pairs

A

help perform same joint movement (quad)

31
Q

Long Bone

A
  • shaft with ends
  • important for leverage and movement
  • femur, phalanges etc
32
Q

Short Bone

A
  • square shaped
  • important for fine movements
  • carpals, tarpals, patella, etc
33
Q

Flat Bone

A
  • important for protection
  • hematopoiesis (make blood)
  • sternum, scapula, ribs etc
34
Q

Irregular Bone

A
  • important for protection, support, movement and hematopoiesis
  • vertebrae, pelvis etc
35
Q

Make up of Bones

A 
Collagen
- 40% dry weight
- toughness and flexibility
Calcium & Salts
- 60% dry weight
-hardness and rigidity
- laid down b/w collagen fibres
36
Q

Osteogenic Cells

A
  • bone cells
  • stem cells
  • develop into osteoblast then osteocyte
37
Q

Osteoclasts

A
  • bone cells
  • very large with many nuclei
  • improves reabsorption efficiency
  • respond to mechanical stress
  • “dig tunnels” to be lined with collagen by osteoblasts
38
Q

Osteocytes

A
  • maintain bone matrix
  • hold bone together
  • mineralise bone matrix
  • long cytoplasmic extensions
  • nutrients to bone matrix
39
Q

Osteoblasts

A
  • line tunnel with collagen
  • create bone matrix (build bone)
  • located on bone surface
  • differentiate into osteocytes when trapped in bone
40
Q

Bone Types

A

Compact Bone:

  • lamellar or cortical
  • hard and dense
  • support body
  • stores calcium
  • organised structure

Trabecular Bone:

  • spongy
  • greater surface area
  • promotes bone marrow to develop
  • trabeculae form along lines of stress
41
Q

Primary / Secondary Ossification Centres

A

primary: form ~ 8 weeks after bone formation
secondary: present after birth until growth stops. involves developing ends of bone

42
Q

Stages of Bone Development

A
  1. resting cartilage
  2. cartilage proliferation (hyperplasia - cells multiplying)
  3. cartilage maturation (hypertrophy)
  4. cartilage calcification (extracellular matric becomes calcified
  5. ossification (osteoblasts form bone)

draw diagram

43
Q

Skeletal Decay

A

Trabecular:

  • decrease in no. of traberculae (small rods within bone) with age
  • bone cannot absorb as much energy without fracture

Osteoporosis:

  • low bone density
  • less able to absorb mechanical force
  • increase fracture risk
44
Q

Action Potentials in Muscles

A
  • myo (muscle) electic APs are initiated by ACh released by the motor neuron
  • ACh binds to proteins on muscle cell membrane, triggering myoelectric AP
  • AP sweeps along the muscle fibre and into the transverse (T) tubules
  • AP potential triggers Ca2+ release from sarcoplasmic reticulum into cytosol
  • calcium ions binds to troponin in actin —> myosin binding sites exposed
  • if ATP is bound to myosin, concerted to ADP + energy –> myosin in active state –> power stroke
  • cycles of myosin cross-bridge formation and breakdown coupled with ATP hydrolysis, slide actin towards M line
  • ADP leaves myosin. another ATP binds to myosin and returns to relaxed state. power stroke begins again when ATP is hydrolysed
  • cytosolic Ca2+ removed by active transport into SR after AP ends
  • tropomyosin blockage of myosin binding sites is restored, contraction ends, muscle fibres relax
45
Q

4 Physiological Factors That Influence Muscle Force

A
  1. sarcomere length
    - influences amount of force
    - 80-120% of resting length is optimal for force production
    - most active tension produces more passive force
  2. no. of single motor units
    - more motor units –> more force
    - motor unit type
    - higher frequency –> more force
  3. PSCA
    - (muscle volume) / (fibre length)
    - higher PSCA –> more force
  4. Contraction Type
    - concentric is weakest
    - eccentric is strongest
46
Q

Oxidative and Glycolytic Skeletal Fibres

A

oxidative: slow, resistant to fatigue
glycolytic: fast, fatigue rapidly

BIOL1040 (7 decks)

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