Test #3 Flashcards

1
Q

All muscles produce

A

Heat during contraction

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2
Q

Cells of muscles (skeletal)

A

Sarcolemma - muscle fiber plasma membrane
Sarcoplasm - muscle fiber cytoplasm
Glycosomes - glycogen storage
Myoglobin - O2 storage

Organelles
–Myofibrils - contractile unit; densely patched rodlike elements; contains striations, sarcomeres, 1000’s of myofilaments; account for 80% of muscle cell volume
–Sarcomere - unit of myofibril; z-disc to z-disc
–Sarcoplasmic reticulum - stores and releases Ca+
–T tubules - protrusion of sarcolemma into cell to reach each muscle fiber

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3
Q

Cells of muscles (smooth)

A

Uninucleated, no striations, no sacromeres, no protective sheaths (endomysium only)

Varicosities of nerve fibers instead of neuromascular junctions

Diffuse junction - wide synaptic cleft

No troponin; calmodulin binds Ca2+
Tropomyosin serves same function as in skeletal,
Caveola - sarcolemma of smooth muscle contains pouch-like infoldings
Myosin heads across the whole length (as opposed to skeletal which is only at the ends)

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4
Q

Where are ACh receptors found?

A

Junctional folds of the sarcolemma/motor end plate

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5
Q
A
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6
Q
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7
Q
A
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8
Q

Steps from nerve stimulation to muscle contraction (skeletal; steps/summary)

A

— A. Neuromuscular junction
— B. Muscle fiber excitation
— C. Excitation-Contracting coupling (activities of the triad)
— D. Cross bridge cycling occurs via the sliding of myofilaments

Summary of steps from nerve stimulation to muscle contraction
1) Motor neuron AP
2) N/T release
3) Muscle cell AP
4) Release of Ca2+ from SR
5) ATP-driven power stroke
6) Sliding of myofilaments

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9
Q

What is an axon terminal?

A

The bulbous distal endings of the terminal branches of an axon where neurotransmitters are released. Takes in Ca2+, releases ACh

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10
Q

What causes action potential?

A

Depolarization of the sarcolemma - the rising membrane voltage crosses a threshold value, and an AP is generated

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11
Q

Three parts of the motor neural junction

A
  1. Axon terminal
  2. Synaptic cleft
  3. Muscle/motor end plate
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12
Q

Troponin vs calmodulin

A

Troponin - skeletal muscle; Ca2+ binds to troponin which causes tropomyosin to expose myosin-binding sites

Calmodulin - smooth muscle; Ca2+ binds to Calmodulin which activates it (which activates MLCK enzymes, which then phosphorylyse heads of the myosin)

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13
Q

MLCK

A

Enzyme (myosin light chain kinase) this activates myosin heads in smooth muscle; causes activation of ATPase

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14
Q

MLCP

A

Enzyme (myosin light chain phosphates) that dephosphorolyses myosin heads in smooth muscle; causes deactivation of ATPase

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15
Q

ATPase

A

Enzyme that hydrolyzes ATP, providing the energy for the power stroke

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16
Q

Three ways to create ATP in the muscles

A

1) Direct phosphorylation of ADP by creatine phosphate (CP)
–Creatine phosphate in the muscle cell stores energy that will be transferred to ADP to recreate ATP
–No oxygen use, 1 ATP per CP, 15 seconds energy

2) Anaerobic pathway: glycolysis and lactic acid formation
–No oxygen use, 2 ATP per glucose & 2 pyruvic acid, 30-40 seconds energy

3) Aerobic pathway - glucose plus three acids AND OXYGEN aerobically respirate in mitochondria
–OXYGEN USE, 32 ATP per glucose, hours of energy

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17
Q

EPOC

A

Excess post-exercise oxygen consumption; EPOC is the amount of oxygen our body consumes following an exercise session that is above and beyond the pre-exercise oxygen consumption baseline

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18
Q

Structural and functional characteristics of the three types of muscle fibers

A
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19
Q

Muscle twitch phases

A

Latent - events of excitation-contraction coupling - no muscle tension

Contraction - cross-bridge formation - tension increases

Relaxation - Ca+ reentry into sarcoplasmic reticulum - tension decreases to zero

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20
Q

Treppe

A

Warming up; enhances availability of Ca and efficiency of enzymes

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21
Q

Hypertrophy vs hyperplasia

A

Hypertrophy - increase in size; hyperplasia - increase in number

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22
Q

Latch-bridge

A

A cross-bridge connection that happens in smooth muscle where the connection can hold indefinitely without ATP resulting in a low energy contraction

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23
Q

Isometric contraction vs isotonic contraction

A

Isometric contraction - no muscle length change; muscle tension increases but does not exceed load; e.g., pushing against a wall

Isotonic contraction - muscle length changes because muscle tension exceeds load
A) Eccentric contractions - muscle lengthens
B) Concentric contractions - muscle shortens

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24
Q

Triad

A

Triad is a T tubule & two terminal cisterns (sarcoplasmic reticulum - releases and reabsorbs calcium)

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25
Q

Motor end plate

A

Junctional folds of the sarcolemma

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26
Q

Disuse atrophy

A

Degeneration and loss of mass due to immobilization or loss of neural stimulation - can begin almost immediately

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27
Q

Agonist/antagonist/synergist

A

Prime mover (agonist) - produces specific movement

Antagonist - opposes or reverses particular movement

Synergist - helps prime movers (adds extra force or efficiency)

Fixator - type of synergist that stabilized the origin of another muscle

28
Q

First class lever

A

Resistance - fulcrum - force

Scissors
Atlanto-occipital joint of the neck tips neck back instead of falling forward

29
Q

Second class lever

A

Fulcrum - resistance - effort

Wheel barrow
Standing on toes

30
Q

Third class lever

A

Resistance - effort - fulcrum

Forceps
Elbow joint during bicep curl

31
Q

Steps from nerve stimulation to muscle contraction (skeletal; part 1)

A

— A. Neuromuscular junction
1) Action potential (AP) arrives at axon terminal
2) Voltage gated calcium channels open, calcium enters motor neurons
3) Calcium entry causes ACh neurotransmitter to be released into synaptic cleft
4) ACh binds to ACh receptors on sarcolemma
5) ACh opens gates of cell, cell brings in Na+ which changes it to positive, resulting in local end plate depolarization called end plate potential (EPP)
6) Acetylcholenesterase - destroys ACh

32
Q

Steps from nerve stimulation to muscle contraction (skeletal; part 2)

A

— B. Muscle fiber excitation
1) The EPP triggers AP in the adjacent sarcolemma

33
Q

Steps from nerve stimulation to muscle contraction (skeletal; part 3)

A

— C. Excitation-Contracting coupling (activities at the triad)
1) Excitation: AP in sarcolemma travels down T-Tubules
2) Contraction: AP effect on terminal cisterns/sarcoplasmic reticulum releases Ca2+ into cytoplasm
3) Ca2+ binds to troponin which shifts tropomyosin to uncover the actin
4) Myosin heads create cross-bridges leading to ATP-driven power stroke

34
Q

Steps from nerve stimulation to muscle contraction (skeletal; part 4)

A

— D. Cross bridge cycling occurs via the sliding of myofilaments

35
Q

Structural organization of the skeletal muscle (sheaths)

A

Connective tissue sheaths
–Deep fascia - dense irregular CT that surrounds muscles and bind similar muscles
–Epimysium - surrounds a muscle
–Perimysium - surrounds fascicle (bundle of fibers)
–Endomysium - surrounds individual muscle fiber
–Muscle fiber - contains microfibrils
–Microfibril - contains 100s to 1000s of myofilaments
–Myofilaments - contain bundles of actin and myosin

36
Q

Primary/secondary curvature

A

Primary curvature (at birth) - thoracic and sacral convex

Secondary curvature (after birth) - cervical and lumbar concave

37
Q

Abnormal spine curvatures

A

Scoliosis - s-shape
Kyphosis -hunchback
Lordosis - pregnant

38
Q

Vertebral regions and their characteristics

A

Cervical (7)
–Atlas (C1) - loses body to axis during development
–Axis (C2)
—–Only ones that have a hole in transverse process for blood flow to brain

Thoracic (12)
–Only ones to have costal facets for ribs

Lumbar (5) - big to carry weight

Sacrum (5) fused
—Coccyx 3-5 fused

39
Q

Insertions vs origins

A

In axial, origins are medial, insertions are lateral

In appendicular origins are proximal, insertions are distal

ONLY INSERTIONS EVER MOVE

40
Q
A
41
Q

Muscle disorders

A

Myasthenia gravis - destruction of ACh receptors; drooping eyelids

Rigor mortis - due to no ATP to release actin and myosin molecules

42
Q

Bone disorders

A

Osteomalacia (adults) & rickets (children) - vit. D deficiency

Osteoporosis - bone absorption exceeds deposit

Paget’s disease - excessing and haphazard bone deposit & resorption causes fast growth & poor developmen

43
Q

Joint disorders

A

Osteoarthritis - cartilage broken down faster than replaced (local)

Rheumatoid arthritis - chronic inflammatory autoimmune disease (systemic)

Gouty arthritis - deposition of uric acid crystals

Lyme disease - caused by bacteria transmitted by tick bites

44
Q

Classes of bones with examples

A

Long bone - medullary cavity, limbs
–Epiphysis
—–Ends of long bones; compact surrounding spongy
-Epiphysial plate
-Diaphysis - shaft
—–Compact bone surrounding central medullary cavity which contains yellow marrow in adults

Short bone - cube shaped bones in wrist & ankle (patella is sesamoid)

Flat bones - sternum, scapulae, ribs, most skull bones; Wormian bones (sutural) develop within sutures of the skull

Irregular bones - complicated shapes, hip & vertebrae

Structure of short, irregular, and flat bone
—Diploe covered by compact bone
—Compact bone sandwiched between CT membranes
—Bone marrow scattered through spongy (NO DEFINED MARROW CAVITY)

45
Q

Axial vs appendicular skeleton

A

Axial (vertebral columns, ribs, clavicle, cranium)

1:2 ratio (number of bones in arms vs legs)

46
Q

Compact vs spongy bone

A

Compact bone (lamellar)
–Haversian system, consisting of rings of bone matrix called lamellae
–Central Haversian canal (contain NAV) & Volkman’s/perforating canals (right angle; connect NAV of periosteum, medullary cavity and central canal)
–Collagen runs in different directions to create strength;
–Support weight and withstand tension stress

Spongy bone (trabeculae)
–No Haversian system, contains irregularly arranged lamellae
–Stores bone marrow
–Site of hematopoiesis
–Add strength and flexibility to bone

47
Q

Diploe

A

Diploe is a subcategory of trabeculae of flat, cranial bone; spongy bone sandwiched between two layers of compact bone

48
Q

Parts and sections of long bone

A

Epiphysis
Ends of long bones; compact surrounding spongy

Epiphysial plate

Diaphysis - shaft
Compact bone surrounding central medullary cavity which contains yellow marrow in adults

49
Q

Locations of red marrow

A

Children: spongy bone and medullary cavities of long bones

Adults: portions of axial skeleton and in proximal epiphyses of humerus and femur, ossa coxae

50
Q

What gives bone flexibility/strength?

A

Trabeculae

51
Q

Organic/inorganic

A

Organic- responsible for flexibility & resilience due to sacrificial bonds in or between collagen
–Cells, matrix (ground substance, protein fiber)
–Osteogenic cells, osteoblasts, osteocytes, bone-lining cells, osteoclasts
Inorganic - responsible for hardness and resistibility to compression
–hydroxyapatites (mineral salts), mainly calcium phosphate crystals

52
Q

General functions of the skeletal system

A

1) provides support and protection
2) sites for muscle attachment
3) site of hemopoiesis (blood cell production)
4) stores calcium & phosphorus

53
Q

Appositional vs interstitial growth

A

Appositional - occurs in perichondral surface (causes width growth)

Interstitial growth - occurs at epiphysial plate (hyaline cartilage) (causes length growth)

54
Q

Which hormones stimulate osteoclasts and Ca ions? Which stimulate osteoblasts?

A

Osteoblasts - growth hormone, thyroid, testosterone/estrogen

Osteoclasts - Parathyroid (raises Ca+), leptin & serotonin inhibit oseoblast

55
Q

Fracture classifications

A

Greenstick fracture - children
Spiral fracture - contact sports

56
Q

Chronological order of bone repaair

A

1) A hematoma forms
2) Fibrocartilaginous callus forms
3) Bony callus forms
4) Bone remodeling occurs

57
Q

Endochondral ossification vs intramembranous ossification locations

A

Endochondral ossification - basically all bones inferior to base of skull, except clavicle

Intramembranous ossification - forms skull and clavicles

58
Q

What affects the velocity & duration of muscle contraction?

A

The load on the muscle fibers

59
Q

Load on the muscle fibers affects what?

A

Velocity & duration of muscle contraction

60
Q

Cells of bone tissue

A

Osteogenic - stem cell in periosteum and endosteum (become osteoblasts or bone-lining cells when stimulated)

Osteoblast - secretes bone matrix, responsible for growth

Osteocytes - no longer dividing, maintains bone matrix

Bone-lining - maintain matrix

Osteoclasts - bone resorption cell; derived from the same hematopoeic that become microphages

61
Q

Similarities and differences between all muscles (ESSAY QUESTION)

A

Similarities
1) Excitability - ability to receive and respond to stimuli
2) Contractility - ability to shorten forcefully when stimulated
3) Extensibility - ability to be stretched
4) Elasticity - ability to recoil at resting length

Differences
1) Smooth muscle has less elaborate SR and no T tubules; SR does store intracellular Ca2+ but most calcium used for contraction has extracellular origins
2) Sarcolemma of smooth muscle contains pouch-like infoldings called caveolae which contain Ca2+ channels
3) Smooth muscles are electrically connected via gap junctions (skeletal muscles are electrically isolated)
4) No striations or sarcomeres in smooth, but do contain myosin and actin filaments
5) Myosin in smooth muscle has heads along the entire filament

62
Q

Sarcomere & striations

A

Sarcomere - unit of myofibril; z-disc to z-disc

Myofilaments - orderly arrangement of actin and myosin
–Actin - thin, light; tropomyosin & troponin are regulatory protein bands; binds with calcium which cause tropomyosin to disengage from site and myosin head’s interact to create cross-bridges
–Myosin - thick, dark; globular heads, myosin tails; during contraction the heads bind to receptors in thin filaments forming cross-bridges

1) I band (“I, acting alone”) - thin filament only
2) A band - length of thick filament (happens across thick and thin filament)
3) H zone - thick filament only
4) Z disk - connectin to actin
5) M line - thick filament linked together with band

63
Q

Functional descriptions of joints & their locations

A

Synarthrosis - immobile
–Suture

Amphiarthrosis - slightly mobile
—Pubic symphysis

Diarthrosis - freely mobile
-Uniaxial
—i) Plane - intercarpal
—ii) Hinge - elbow
—iii) Pivote - atlantoaxial
-Biaxial
—iv) Condylar - metacarpal
—v) Saddle - first metacarpal
-Multiaxial
—vi) Ball and socket - hip

64
Q

Types of cartilages and locations

A

Hyaline (most abundant) - support, flexibility and resilience, type II collagen
–joints
–ribs

Elastic - similar to hyaline but w/elastic fibers
–external ear

Fibrocartilage - thick collagen fibers - combines considerable tensile strength and ability to resist compressive forces & distribute them evenly to bone
–intervertebral disc
–pubic symphysis
–knee menisci

65
Q

Compare & contrast bones/cartilage

A

Bones
1) Support
2) Protection
3) Movement
4) Mineral and growth factor storage
5) Blood cell formation
6) Triglyceride (fat) storage
7) Hormone production

Cartilage - no blood vessels or nerves
1) Support
2) Flexibility
3) Resilience

66
Q

Bone formation (osteogenesis) vs bone remodeling/repair

A

Ossification (osteogenesis) - begins in month two of development; post-natal until early adulthood
–Endochondral ossification - bones form by replacing hyaline cartilage;
–Intramembranous ossification - bone develops from fibrous membrane

–Interstitial - pushes epiphysial plate up and away from diaphysis
–Appositional - width (most typical in bone remodeling/repair)

Remodeling/repair is lifelong