Ch11 Muscular Tissue Flashcards
1
Q
Skeletal Muscle
- attached to…
- _____ - _____ control
- _____ - alternating ____ & _____ bands (results from overlapping internal ______)
A
Skeletal Muscle
- attached to BONE(S)
- VOLUNTARY - CONSCIOUS control
- STRIATIONS - alternating LIGHT & DARK bands (results from overlapping internal CONTRACTILE PROTEINS)
2
Q
Muscle cell =
- as long as…
A
Muscle cell = muscle fiber (myofiber)
- as long as 30cm
3
Q
What are the universal characteristics of muscle?
A
- Responsiveness (excitability)
- Conductivity
- Extensibility
- Elasticity
- Contractility
4
Q
How is muscle responsive/excitable?
A
Reponsive/excitable to chemical signals, stretch, and electrical changes across plasma membrane
5
Q
How is muscle conductive?
A
Local electrical change triggers excitation wave that travels along muscle fiber
6
Q
How is muscle extensible?
A
Capable of being stretched between contractions
7
Q
How is muscle elastic?
A
Returns to original resting length after being stretched
8
Q
How is muscle contractable?
A
Shortens when stimulated
9
Q
Connective Tissue Elements
- perimysium surrounds…
- epimysium surrounds…
- endomysium surrounds…
A
Connective Tissue Elements
- perimysium surrounds MUSCLE FASCICLES
- epimysium surrounds ENTIRE MUSCLE
- endomysium surrounds MUSCLE CELLS
10
Q
Connective Tissue Elements
Tendons attach ____ to ____; lots of ____
- _____ slightly under ____, ____ when ____
- resists _______, protects ____ from ___
- returns ____ to its _____
A
Connective Tissue Elements
Tendons attach MUSCLE to BONE; lots of COLLAGEN
- STRETCHES slightly under TENSION, RECOILS when RELEASED
- resists EXCESSIVE STRETCHING, protects MUSCLE from INJURY
- returns MUSCLE to its RESTING LENGTH
11
Q
Muscle Fiber (Cell)
- Sarcolemma =
- Sarcoplasm =
- Glycogen =
- Myoglobin =
- Multiple Nuclei = (due to ___ of several ___)
- Myofibrils =
A
Muscle Fiber (Cell)
- Sarcolemma = PLASMA MEMBRANE
- Sarcoplasm = CYTOPLASM
- Glycogen = STORED TO PROVIDE ENERGY
- Myoglobin = RED PIGMENT, STORES O₂ FOR MUSCLE ACTIVITY
- Multiple Nuclei = FLATTENED, PRESSED AGAINST INSIDE OF SARCOLEMMA (due to FUSION of several MYOBLASTS)
- Myofibrils = LONG PROTEIN BUNDLES WITHIN A SARCOPLASM
12
Q
Muscle Fiber
- Sarcoplasmic Reticulum (SR) - __ ER, network ___ each ____: ____ reservoir
- Terminal Cisternae - ______ of SR
- T Tubules - tubular ____ of ____, penetrate through ____, emerge _____
- Triad - _____ + _____
A
Muscle Fiber
- Sarcoplasmic Reticulum (SR) - SMOOTH ER, network AROUND each MYOFIBRIL: CALCIUM reservoir
- Terminal Cisternae - DILATED END-SACS of SR
- T Tubules - tubular INFOLDINGS of SARCOLEMMA, penetrate through CELL, emerge ON OTHER SIDE
- Triad - T TUBULE + 2 TERMINAL CISTERNS
13
Q
Myofilaments
- thick filaments: ___ - 500____ molecules
- ______ (like golf clubs) ____
- ___ directed ____ in ___ array around ___
- ___ zone with no ____ in ____
A
Myofilaments
- thick filaments: 200 - 500 MYOSIN molecules
- 2 CHAINS (like golf clubs) INTERTWINED
- HEADS directed OUTWARD in HELICAL array around BUNDLE
- BARE zone with no HEADS in MIDDLE
14
Q
Myofilaments
- Thin filaments - ____ strands of _____
- string of _____ subunits; have ____ to bind ___ of ___
- tropomyosin molecules - ____ active sites on ____
- troponin molecule - ____, Ca+2 _____ on each _____ molecule
A
Myofilaments
- Thin filaments - 2 INTERTWINED strands of FIBROUS (F) ACTIN
- string of GLOBULAR (G) ACTIN subunits; have ACTIVE SITE to bind HEAD of MYOSIN
- tropomyosin molecules - BLOCK active sites on G ACTIN
- troponin molecule - SMALL, Ca+2 BINDING PROTEIN on each TROPOMYOSIN molecule
15
Q
A
16
Q
Myofilaments
Elastin filaments
- titin (____): ___ springy ____
- ___ each ____ filament, ___ it to ____
- ____ thick filament, ____ it betweeen ____
- prevent ____
A
Myofilaments
Elastin filaments
- titin (CONNECTIN): HUGE, springy PROTEIN
- FLANK each THICK filament, ANCHOR it to Z DISC
- STABILIZES thick filament, CENTERS it betweeen THIN FILAMENTS
- prevent OVERSTRETCHING
17
Q
Myofilament
- contractile proteins- ___ & ____
- regulatory proteins - ___ & ____
- determine ___ and ___ of ____
- _____ released from _____ binds to ____
- ___ moves ____ off _____ on ___
- accessory proteins
- anchor ____
- regulate _____
A
Myofilaments
- contractile proteins- MYOSIN & ACTIN
- regulatory proteins - TROPOMYOSIN & TROPONIN
- determine START and STOP of CONTRACTION
- CA+2 released from SARCOPLASM binds to TROPONIN
- TROPONIN moves TROPOMYOSIN off ACTIVE SITES on ACTIN
accessory proteins
- anchor MYOFILAMENTS
- regulate LENGTH
18
Q
Myofilaments
- dystrophin - most ____ important ______
- genetic defect =
A
Myofilaments
- dystrophin - most CLINICALLY important ACCESSORY PROTEIN
- genetic defect = MUSCULAR DYSTROPHY
19
Q
Striations
- A band =
- H band =
- M line =
- I band =
- Z disc = and ___
A
Striations
- A band = DARK, ANISOTROPIC
- H band = MIDDLE OF A BAND; THICK FILAMENTS ONLY
- M line = BISECTS H BAND
- I band = ALTERNATING LIGHTER BAND; ISOTROPIC
- Z disc = PROVIDES ACHORAGE FOR THIN FILAMENTS AND ELASTIC FILAMENTS and BISECTS I BAND
20
Q
A
21
Q
Striations
- sacromere - segment from ____ to ___
- _____ shorten because individual ____ shorten
- _____ ( _ lines) pulled ____, ____ and ___ filaments ___ past each other
- neither ___ nor ___ change ___ during ___
- only ____ of ___ changes
A
Striations
- sacromere - segment from Z DISC to Z DISC
- MUSCLE CELLS shorten because individual SACROMERES shorten
- Z DISC ( Z lines) pulled CLOSER TOGETHER, THICK and THIN filaments SLIDE past each other
- neither THICK nor THIN change LENGTH during SHORTENING
- only AMOUNT of OVERLAP changes
22
Q
NERVE - MUSCLE RELATIONSHIP
- somatic motor neurons - serve ____
- ____ of _____ = somatic ___ fibers; lead to ____
- motor unit = one nerve fiber + _____
A
NERVE - MUSCLE RELATIONSHIP
- somatic motor neurons - serve SKELETAL MUSCLE
- AXONS of MOTOR NEURONS = somatic MOTOR fibers; lead to SKELETAL MUSCLE
- motor unit = one nerve fiber + ALL MUSCLE FIBERS IT INNERVATES
23
Q
Motor Units
- average motor unit = ____ for each motor unit
- small motor units = ___degree of ____ ( __ - ___ muscle ___ per ___; ___ & ___ muscle)
- large motor units = more ____ than ___ (gastrocnemius has 1,000 ____ per ___)
A
Motor Units
- average motor unit = 200 MUSCLE FIBERS for each motor unit
- small motor units = FINE degree of CONTROL ( 3 - 6 muscle FIBERS per NEURON; EYE & HAND muscle)
- large motor units = more STRENGTH than CONTROL (gastrocnemius has 1,000 MUSCLE FIBERS per NEURON)
24
Q
Neuromuscular Junction (NMJ)
- NMJ = _____ between ____ and ____ (cell)
- Acetylcholine (ACh) is ____ from _____
*
A
Neuromuscular Junction (NMJ)
- NMJ = FUNCTIONAL CONNECTION between NERVE FIBER and MUSCLE FIBER (cell)
- Acetylcholine (ACh) is RELEASED from NERVE FIBER
25
**Components of NMJ**
* synaptic knob = __ end of \_\_\_
* synaptic cleft = tiny ___ between ___ and \_\_\_
* basal lamina = thin ____ + ____ layer over all \_\_\_\_\_
* junctional folds = region of ____ (increases ___ and has \_\_\_\_)
*
**Components of NMJ**
* synaptic knob = SWOLLEN end of NERVE FIBER
* synaptic cleft = tiny GAP between NERVE and MUSCLE
* basal lamina = thin COLLAGENOUS + GLYCOPROTEIN layer over all MUSCLE FIBER
* junctional folds = region of SARCOLEMMA (increases SURFACE AREA and has ACETYLCHOLINESTERASE)
26
**Electrically Excitable Cells**
* ______ and neurons are _______ cells
* ____ membrane is ___ or ___ - high concentration NA+ \_\_\_\_\_\_, but K+ (other \_\_\_) \_\_\_\_
* ______ in ____ across ___ = ______ (RMP; __ mV cell)
**Electrically Excitable Cells**
* MUSCLE FIBERS and neurons are ELECTRICALLY EXCITABLE cells
* PLASMA membrane is POLARIZED or CHARGED - high concentration NA+ OUTSIDE CELL, but K+ (other ANIONS) INSIDE CELL
* DIFFERENCE in CHARGE across MEMBRANE = RESTING MEMBRANE POTENTIAL (RMP; -90 mV cell)
27
**Electrically Excitable Cells (Muscle and Neurons)**
* _____ of _____ charge at ____ (thus it is ___ or \_\_\_\_\_)
**Electrically Excitable Cells (Muscle and Neurons)**
* IMBALANCE of ELECTRICAL charge at PLASMA MEMBRANE (thus it is CHARGED or ELECTRICALLY UNSTABLE)
28
**Muscle Contraction and Relaxation**
- 4 actions involved in this process
* Excitation = ____ potentials lead to _____ potentials in \_\_\_\_\_\_
* Excitation-contraction coupling = ___ potentials on _____ activate \_\_\_\_
* Contraction = ____ of ____ fiber
* Relaxation = return to \_\_\_
**Muscle Contraction and Relaxation**
- 4 actions involved in this process
* Excitation = NERVE ACTION potentials lead to ACTION potentials in MUSCLE FIBER
* Excitation-contraction coupling = ACTION potentials on SARCOLEMMA activate MYOFILAMENTS
* Contraction = SHORTENING of MUSCLE fiber
* Relaxation = return to RESTING LENGTH
29
**Excitation Steps 1 & 2**
* ____ signals opens voltage-gated ___ channels in ___ terminal
* ___ stimulates ____ of ACh from \_\_\_\_\_
* ACh released into \_\_\_\_
**Excitation Steps 1 & 2**
* NEURAL signals opens voltage-gated CA+2 channels in AXON terminal
* CA+2 stimulates EXOCYTOSIS of ACh from SYNAPTIC VESICLES
* ACh released into SYNAPTIC CLEFT
30
**Excitation Steps 3, 4**
* ACh molecules bind to \_\_\_\_\_, open ___ & ___ channels
* ___ enters; shifting RMP from \_\_mV to \_\_mV, then __ exits, RMP returns to \_\_mV; quick voltage shift = ______ (\_\_)
**Excitation Steps 3, 4**
* ACh molecules bind to RECEPTOR PROTEIN, open NA+ & K+ channels
* NA+ enters; shifting RMP from -90mV to +75mV, then K+ exits, RMP returns to -90mV; quick voltage shift = END-PLATE POTENTIAL (EPP)
31
**Excitation Step 5**
* ______ (EPP) in end-plate region ____ nearby ______ channels
* produces _____ (\_\_) that spreads over \_\_\_\_
**Excitation Step 5**
* VOLTAGE CHANGE (EPP) in end-plate region OPENS nearby VOLTAGE-GATED channels
* produces ACTION POTENTIAL (AP) that spreads over MUSCLE SURFACE
32
**Excitation - Contraction Coupling steps 6, 7**
* ___ spreads down into \_\_\_
* opens ____ ion channels in ____ and CA+2 channels in \_\_\_
* CA+2 enters \_\_\_
*
**Excitation - Contraction Coupling steps 6, 7**
* AP spreads down into T TUBULES
* opens VOLTAGE-GATED ion channels in T TUBULES and CA+2 channels in SR
* CA+2 enters CYTOSOL
33
**Excitation - Contraction Coupling Steps 8, 9**
* CA+2 binds to ____ in thin \_\_\_
* ______ complex changes \_\_\_\_, exposes active sites on \_\_\_
**Excitation - Contraction Coupling Steps 8, 9**
* CA+2 binds to TROPONIN in thin FILAMENTS
* TROPONIN-TROPOMYOSIN complex changes SHAPE, exposes active sites on ACTIN
34
**Contraction Steps 10, 11**
* ____ ATPase in ___ head ____ ATP
* activates head "\_\_\_" it in ___ position (ADP + Pi remain \_\_\_)
* head binds to ____ active site forming a \_\_\_\_-actin ___ - bridge
**Contraction Steps 10, 11**
* MYOSIN ATPase in MYOSIN head HYDROLYZES ATP
* activates head "COCKING" it in EXTENDED position (ADP + Pi remain ATTACHED)
* head binds to ACTIN active site forming a MYOSIN-actin CROSS-bridge
35
**Contraction Steps 12, 13**
* ___ head releases ADP & \_\_\_, flexes, pulls thin ____ past thick --- \_\_\_\_
* upon binding more ATP, ____ releases \_\_\_\_; process _____ (each ___ performs # \_\_\_\_/second)
**Contraction Steps 12, 13**
* MYOSIN head releases ADP & Pi, flexes, pulls thin FILAMENT past thick --- POWER STROKE
* upon binding more ATP, MYOSIN releases ACTIN; process REPEATS (each HEAD performs 5 STROKES/second)
36
**Relaxation Steps 14, 15**
* ____ stimulation, ACh release \_\_\_\_
* AChE ___ down ACh, fragments _____ into _____ knob
*
**Relaxation Steps 14, 15**
* NEURAL stimulation, ACh release STOPS
* AChE BREAKS down ACh, fragments REABSORBED into SYNAPTIC knob
37
**Relaxation Step 16**
* Ca+2 pumped back into ___ by \_\_\_\_\_
* Ca+2 binds to ____ while in storage in \_\_\_
* ATP for muscle ___ as well as muscle \_\_\_\_
**Relaxation Step 16**
* Ca+2 pumped back into SR by ACTIVE TRANSPORT
* Ca+2 binds to CALSEQUESTRIN while in storage in SR
* ATP for muscle RELAXATION as well as muscle CONTRACTION
38
**Relaxation Steps 17, 18**
* Ca+2 removed from \_\_\_\_\_, pumped back into \_\_\_\_
* _____ reblocks active sites
* ____ ceases to produce or maintain \_\_\_\_\_
* _____ returns to its ______ (recoil of ___ components and contraction of _____ muscles)
**Relaxation Steps 17, 18**
* Ca+2 removed from TROPONIN, pumped back into SR
* TROPOMYOSIN reblocks active sites
* MUSCLE FIBER ceases to produce or maintain TENSION
* MUSCLE FIBER returns to its RESTING LENGTH (recoil of ELASTIC components and contraction of ANTAGONISTIC muscles)
39
**Length - Tension Relationship & Muscle Tone**
* amount of _____ generated by ____ depends on ___ before it was \_\_\_\_
1. overly contracted = ____ contraction results (\_\_\_\_ too close to \_\_\_, cannot slide)
2. too stretched = ___ contraction results (\_\_\_ overlap of ___ and ___ does not allow many ____ to form)
* optum resting length produces ___ when muscle \_\_\_
(\_\_\_\_ maintains optimal ___ to produce ___ or partial \_\_\_)
**Length - Tension Relationship & Muscle Tone**
* amount of TENSION generated by MUSCLE depends on LENGTH before it was STIMULATED
1. overly contracted = WEAK contraction results (THICK FILAMENT too close to Z DISCS, cannot slide)
2. too stretched = WEAK contraction results (LITTLE overlap of THICK and THIN does not allow many CROSS-BRIDGES to form)
* optum resting length produces GREATEST FORCE when muscle CONTRACTS
(CNS maintains optimal LENGTH to produce MUSCLE TONE or partial CONTRACTION)
40
**Muscle Twitch (Frog)**
* threshold -\_\_\_ voltage necessary to generate ______ and produce \_\_\_
* twitch - quick cycle of \_\_\_\_/\_\_\_\_ when stimulus at ____ or ____ (
**Muscle Twitch (Frog)**
* threshold - MINIMUM voltage necessary to generate ACTION POTENTIAL and produce CONTRACTION
* twitch - quick cycle of CONTRACTION/RELAXATION when stimulus at THRESHOLD or HIGHER (\<0.1 sec)
41
**Muscle Twitch Phases**
* latent period = \_\_\_ms delay between onset of ____ and onset of ___ response
* contraction phase = ____ slide, muscle \_\_\_
* relaxation phase - __ quickly reabsorbs Ca2+, ___ releases thin \_\_\_\_, ____ declines (muscle returns to \_\_\_)
**Muscle Twitch Phases**
* latent period = 2ms delay between onset of STIMULUS and onset of TWITCH response
* contraction phase = FILAMENT slide, muscle SHORTENS
* relaxation phase - SR quickly reabsorbs Ca2+, MYOSIN releases thin FILAMENTS, TENSION declines (muscle returns to RESTING LENGTH)
42
**Contraction Strength of Twitches**
* _____ stimuli produces \_\_\_
old quote: "muscle fiber obeys an all-or none law" meaning they contract to maximum or not at all ... true?
- no... ___ vary in \_\_
- depends on: Ca2+ \_\_\_\_, previous stretch of \_\_\_\_, temperature, \_\_, hydration
- closer ____ produces stronger \_\_\_\_
**Contraction Strength of Twitches**
* THRESHOLD stimuli produces TWITCHES
old quote: "muscle fiber obeys an all-or none law" meaning they contract to maximum or not at all ... true?
- no... TWITCHES vary in STRENGTH
- depends on: Ca2+ CONCENTRATION, previous stretch of MUSCLE, temperature, pH, hydration
- closer STIMULI produces stronger TWITCHES
43
**Contraction Strength of Twitches**
* stimulating whole ___ with higher and higher voltages produces \_\_\_\_\_
* more motor units are recruited = _____ (\_\_) summation (ex- lift glass of milk vs whole gallon)
**Contraction Strength of Twitches**
* stimulating whole NERVE with higher and higher voltages produces STRONGER CONTRACTIONS
* more motor units are recruited = MULTIPLE MOTOR UNIT (MMU) summation (ex- lift glass of milk vs whole gallon)
44
**Contraction of Twitches**
* when stimulus ____ (voltage) is \_\_\_, twitch strength can ___ with stimulus \_\_\_\_
* low frequency (up to ___ stim/sec) - each stimulus produces ___ twitches, full ___ follows
* moderate frequency (\_\_-\_\_ stim/sec) - each twitch \_\_\_, but develops more ___ than previous = \_\_\_
- Ca+2 not completely back in \_\_
- __ increases myosin ATPase ____ (\_\_\_ twitches as ___ warms up)
**Contraction of Twitches**
* when stimulus INTENSITY (voltage) is CONSTANT, twitch strength can VARY with stimulus FREQUENCY
* low frequency (up to 10 stim/sec) - each stimulus produces IDENTICAL twitches, full RECOVERY follows
* moderate frequency (10-20 stim/sec) - each twitch RECOVERS, but develops more TENSION than previous = TREPPE
- Ca+2 not completely back in SR
- HEAT increases myosin ATPase EFFICIENCY (STRONGER twitches as MUSCLE warms up)
45
**Contraction Strength of Twitches**
* higher freqency (\_\_-\_\_ stim/sec) - generates more strength of \_\_\_\_
- each stimulus arrives before last one \_\_\_, new twitch rides "piggy-back" on previous one, generates higher \_\_\_
- temporal (wave) summation - stimuli arriving \_\_\_
- incomplete tetanus = sustained ___ contractions
* maximum frequency (\_\_-\_\_ stim/sec) - __ has no time to ___ at all
- twitches ___ into smooth, prolonged ___ = ___ tetanus
- rarely occurs in the \_\_\_
**Contraction Strength of Twitches**
* higher freqency (20-40 stim/sec) - generates more strength of CONTRACTION
- each stimulus arrives before last one RECOVERS, new twitch rides "piggy-back" on previous one, generates higher TENSION
- temporal (wave) summation - stimuli arriving CLOSE TOGETHER
- incomplete tetanus = sustained FLUTTERING contractions
* maximum frequency (40-50 stim/sec) - MUSCLE has no time to RELAX at all
- twitches FUSES into smooth, prolonged CONTRACTION = COMPLETE tetanus
- rarely occurs in the BODY
46
**Isometric & Isotonic Contraction**
* isometric muscle contraction
- develops ___ without changing \_\_\_
- important in ___ muscle function and ____ muscle joint \_\_\_\_
* isotonic muscle contraction
- changes in ___ with no change in \_\_\_
* concentric contraction = ___ while \_\_\_
* eccentric contraction = ___ while \_\_\_
**Isometric & Isotonic Contraction**
* isometric muscle contraction
- develops TENSION without changing LENGTH
- important in POSTURAL muscle function and ANTAGONISTIC muscle joint STABILIZATION
* isotonic muscle contraction
- changes in LENGTH with no change in TENSION
* concentric contraction = TENSION while SHORTENING
* eccentric contraction = TENSION while LENGTHENING
47
**Isometric and Isotonic Contraction**
*ISOMETRIC AND ISOTONIC PHASES OF LIFTING*
* beginning - ___ phase (muscle tension ___ but muscles do not \_\_\_) ex, box not moving
* when ___ overcomes ____ of load (\_\_\_ levels off)
* ___ beings to ___ - ___ phase (box being lifted)
**Isometric and Isotonic Contraction**
*ISOMETRIC AND ISOTONIC PHASES OF LIFTING*
* beginning - ISOMETRIC phase (muscle tension RISES but muscles do not SHORTEN) ex, box not moving
* when TENSION overcomes RESISTANCE of load (TENSION levels off)
* MUSCLE beings to SHORTEN - ISOTONIC phase (box being lifted)
48
**ATP Sources**
* all _____ depends on \_\_\_
* pathways of ___ synthesis
- anaerobic formation (ATP production \_\_\_) - without \_\_\_, produces ___ lactic acid
- aerobic respiration (\_\_ ATP produced) - requires continuous \_\_\_, produces ___ and CO2
**ATP Sources**
* all MUSCLE CONTRACTION depends on ATP
* pathways of ATP synthesis
- anaerobic formation (ATP production LIMITED) - without OXYGEN, produces TOXIC lactic acid
- aerobic respiration (MORE ATP produced) - requires continuous OXYGEN, produces H20 and CO2
49
**Immediate Energy**
* short, intense exercise (100m dash) - O2 need supplied by \_\_\_
* phosphagen system
- \_\_\_\_\_: transfers Pi from one ___ to another forming \_\_\_
- creating kinase: transfers Pi from ____ (\_\_) to make ___ (provides energy for 1 minute of brisk walking or 6 seconds of sprinting)
**Immediate Energy**
* short, intense exercise (100m dash) - O2 need supplied by MYOGLOBIN
* phosphagen system
- MYOKINASE: transfers Pi from one ADP to another forming ATP
- creating kinase: transfers Pi from CREATINE PHOSPHATE (CP) to make ATP (provides energy for 1 minute of brisk walking or 6 seconds of sprinting)
50
**Short Term Energy**
* glycogen-lactic acid system = takes over when _____ exhausted, glycogen to lactic acid (\_\_\_\_\_\_\_\_\_)
* produces enough ATP for \_\_\_-\_\_ sec of ___ activity
* muscle obtains ____ from ___ and stored \_\_\_
**Short Term Energy**
* glycogen-lactic acid system = takes over when PHOSPHAGEN SYSTEM exhausted, glycogen to lactic acid (ANEROBIC RESPIRATION)
* produces enough ATP for 30-40 sec of MAXIMUM activity
* muscle obtains GLUCOSE from BLOOD and stored GLYCOGEN
51
**Long-Term Energy**
* ________ is needed for prolonged \_\_\_\_(36 ATP/glucose)
* after 40 sec, ___ and _____ systems "catch up", deliver O2 to ____ fast enough for ______ to meet ___ demands
* O2 consumption rate rises for 3-4 minutes, then \_\_\_\_, ATP production keeps ____ with \_\_\_
* limits set by depletion of \_\_\_\_, blood glucose, loss of fluid and electrolytes, set limits on \_\_\_\_\_
Long-Term Energy
* AEROBIC RESPIRATION is needed for prolonged EXERCISE (36 ATP/glucose)
* after 40 sec, RESPIRATORY and CARDIOVASCULAR systems "catch up", deliver O2 to MUSCLES fast enough for AEROBIC RESPIRATION to meet ATP demands
* O2 consumption rate rises for 3-4 minutes, then LEVELS OFF, ATP production keeps PACE with DEMAND
* limits set by depletion of GLYCOGEN, blood glucose, loss of fluid and electrolytes, set limits on ENDURANCE
52
**Fatigue**
* Muscle fatigue = progressive _____ from ____ use
* Fatigue thought to result from:
- ATP synthesis declines as ______ consumed
- Na+ - K+ pumps fail to keep _____ potential and \_\_\_\_
- _____ inhibits enzyme function
- accumulation of extracellular K+ _____ cell; makes muscle fiber \_\_\_\_
- ______ fibers use up their acetylcholine
**Fatigue**
* Muscle fatigue = progressive WEAKNESS from PROLONGED use
* Fatigue thought to result from:
- ATP synthesis declines as GLYCOGEN consumed
- Na+ - K+ pumps fail to keep MEMBRANE potential and EXCITABILITY
- LACTIC ACID inhibits enzyme function
- accumulation of extracellular K+ HYPERPOLARIZES cell; makes muscle fiber LESS EXCITABLE
- MOTOR NEURON fibers use up their acetylcholine
53
**Endurance**
* ability to maintain _____ exercise \> 5 minutes
* Determined by:
- maximum O2 uptake = uptake ___ to body size, peaks at age \_\_, best in well-conditioned \_\_\_\_
- nutrient availability = _____ packs extra ____ into muscle cells & extra adds 2.7g water / g glycogen
**Endurance**
* ability to maintain HIGH-INTENSITY exercise \> 5 minutes
* Determined by:
- maximum O2 uptake = uptake PROPORTIONATE to body size, peaks at age 20, best in well-conditioned ATHLETES
- nutrient availability = CARB-LOADING packs extra GLYCOGEN into muscle cells & extra adds 2.7g water / g glycogen
54
**Oxygen Debt**
* ______ continues after strenuous exercise
* _______ (EPOC): typically ~11L extra needed after strenuous exercise
* purpose for extra O2:
- replace oxygen ___ (myoglobin, blood hemoglobin, etc)
- replenishing ____ system
- oxidizing ___ back to ____ in liver and kidneys
- serving elevated \_\_\_\_\_
**Oxygen Debt**
* HEAVY BREATHING continues after strenuous exercise
* EXCESS POSTEXERCISE OXYGEN CONSUMPTION (EPOC): typically ~11L extra needed after strenuous exercise
* purpose for extra O2:
- replace oxygen RESERVES (myoglobin, blood hemoglobin, etc)
- replenishing PHOSPHAGEN system
- oxidizing LACTIC ACID back to GLUCOSE in liver and kidneys
- serving elevated METABOLIC RATE
55
**Slow Twitch, Fast Twitch**
* slow oxidative (SO), \_\_\_\_
- abundant mitochondria, myoglobin, \_\_\_\_
- adapted for ____ respiration and ___ resistance
- relative ___ twitch lasting about 100ms/twitch
- ___ (jogging); postural muscles of \_\_\_
**Slow Twitch, Fast Twitch**
* slow oxidative (SO), SLOW-TWITCH
- abundant mitochondria, myoglobin, CAPILLARIES
- adapted for AEROBIC respiration and FATIGUE resistance
- relative LONG twitch lasting about 100ms/twitch
- SOLEUS (jogging); postural muscles of BACK
56
**Slow Twitch, Fast Twitch**
* Fast glycolytic (FG), \_\_\_\_
- fibers well-adapted for ______ but not ____ resistance
- rich in enzymes of _____ and glycogen-\_\_\_\_\_\_systems
* SR releases and reabsorbs CA2+ quickly so __________ quicker (7.5ms/twitch)
* eye muscles, gastrocnemius (\_\_\_\_), biceps brachii
**Slow Twitch, Fast Twitch**
* Fast glycolytic (FG), FAST-TWITCH
- fibers well-adapted for QUICK RESPONSE but not FATIGUE resistance
- rich in enzymes of PHOSPHAGEN and glycogen-LACTIC ACID systems
* SR releases and reabsorbs CA2+ quickly so CONTRACTIONS quicker (7.5ms/twitch)
* eye muscles, gastrocnemius (JUMPING), biceps brachii
57
**Muscular Strength and Conditioning**
* Strength of Contraction depends on:
- ___ size and fascicle arrangement (3 or 4 kg/cm2 of cross-sectional area)
- size of ______ units and _____ recruitment
- length of muscle at start of \_\_\_\_
* resistance training (weight lifting)
- stimulates cell _____ due to synthesis of more myofilaments
* endurance training (\_\_\_\_ exercise)
- produces increase in \_\_\_\_\_, glycogen and density of capillaries
**Muscular Strength and Conditioning**
* Strength of Contraction depends on:
- MUSCLE size and fascicle arrangement (3 or 4 kg/cm2 of cross-sectional area)
- size of MOTOR units and MOTOR UNIT recruitment
- length of muscle at start of CONTRACTION
* resistance training (weight lifting)
- stimulates cell ENLARGEMENT due to synthesis of more myofilaments
* endurance training (AEROBIC exercise)
- produces increase in MITOCHONDRIA, glycogen and density of capillaries
58
**Cardiac Muscle**
* \_\_\_\_, thick cells with \_\_\_, notched ends
* linked to each other at \_\_\_\_\_
- electrical ____ allow cells to stimulate neighbors
- ______ keep cells from pulling apart
SR less \_\_\_\_, but larger T tubules admit CA+2 from ___ fluid
**Cardiac Muscle**
* STRIATED, thick cells with UNEVEN, notched ends
* linked to each other at INTERCALATED DISCS
- electrical GAP JUNCTIONS allow cells to stimulate neighbors
- MECHANICAL JUNCTIONS keep cells from pulling apart
SR less DEVELOPED, but larger T tubules admit CA+2 from EC fluid
59
**Cardiac Muscle**
* ____ due to pacemaker cells
* uses ______ respiration almost exclusively
- large mitochondria make it ____ resistant
- rich in ____ and \_\_\_
- very vulnerable to interruptions in _____ supply
* damaged cells repaired by ___ not mitosis
* autonomic nervous system sends nerve fibers to \_\_\_, regulates \_\_\_
**Cardiac Muscle**
* AUTORHYTHMIC due to pacemaker cells
* uses AEROBIC RESPIRATION respiration almost exclusively
- large mitochondria make it FATIGUE resistant
- rich in MYOGLOBIN and GLYCOGEN
- very vulnerable to interruptions in OXYGEN supply
* damaged cells repaired by FIBROSIS not mitosis
* autonomic nervous system sends nerve fibers to HEART, regulates RATE
60
**Smooth Muscle**
* ____ shape, no striations, sacromeres, z-lines (replaced by ____ bodies)
**Smooth Muscle**
* FUSIFORM shape, no striations, sacromeres, z-lines (replaced by DENSE bodies)
61
**Smooth Muscle Contraction**
* ____ filaments pull on ____ filaments attached to ____ bodies on plasma membrane
* shortens entire cell in ____ fashion
**Smooth Muscle Contraction**
* THIN filaments pull on INTERMEDIATE filaments attached to DENSE bodies on plasma membrane
* shortens entire cell in TWISTING fashion
62
**Smooth Muscle**
* SR is scanty, no \_\_\_\_\_
* CA2+ triggering contraction comes from \_\_\_
- CA+2 channels triggered to open by voltage, hormones, neurotransmitters, or cell \_\_\_\_
- if present, nerve supply \_\_\_\_, not somatic (like skeletal)
- _____ and _____ slow in comparison
- uses 10-300 times less \_\_\_
- capable of mitosis and hyperplasia
- injured smooth muscle _____ well
**Smooth Muscle**
* SR is scanty, no T TUBULES
* CA2+ triggering contraction comes from ECF
- CA+2 channels triggered to open by voltage, hormones, neurotransmitters, or cell STRETCHING
- if present, nerve supply AUTONOMIC, not somatic (like skeletal)
- CONTRACTION and RELAXATION slow in comparison
- uses 10-300 times less ATP
- capable of mitosis and hyperplasia
- injured smooth muscle REGENERATES well
63
**Muscular Dystrophy**
* group of _____ diseases, skeletal muscles ____ and weaken; replaced with fat and fibrous scar tissue
* Muchenne MD = self-linked ___ trait (1 of 3,500 live-born boys)
- most ___ form; diagnosed ages 2-10
- mutation in gene for muscle ____ (actin not linked to sarcolemma, cell membranes _____ during contraction, necrosis, and scar tissue result
- rarely live past 20
**Muscular Dystrophy**
* group of HEREDITARY diseases, skeletal muscles DEGENERATE and weaken; replaced with fat and fibrous scar tissue
* Muchenne MD = self-linked RECESSIVE trait (1 of 3,500 live-born boys)
- most COMMON form; diagnosed ages 2-10
- mutation in gene for muscle PROTEIN (actin not linked to sarcolemma, cell membranes DAMAGED during contraction, necrosis, and scar tissue result
- rarely live past 20
64
**Muscular Dystrophy**
* facioscapulohumeral MD - autosomal ____ trait affecting both sexes equally
* - facial and shoulder muscles more than ___ muscles
**Muscular Dystrophy**
* facioscapulohumeral MD - autosomal DOMINANT trait affecting both sexes equally
* - facial and shoulder muscles more than PELVIC muscles
65
**Myasthenia Gravis**
* autoimmune disease = antibies attack \_\_\_, bind ACh receptors together in clusters
- muscle fibers ___ receptor clusters from sarcolemma
- fiber becomes less ___ to ACh
- disease of ____ between 20-40
- effect usually first appear in ___ muscles (drooping eyelids, double vision, difficulty swallowing, limb weakness)
* strabismus = inability to ____ on same point with both \_\_\_
* treatments = cholinesterase ___ and _____ agents
**Myasthenia Gravis**
* autoimmune disease = antibies attack NMJs, bind ACh receptors together in clusters
- muscle fibers REMOVE receptor clusters from sarcolemma
- fiber becomes less SENSITIVE to ACh
- disease of WOMEN between 20-40
- effect usually first appear in FACIAL muscles (drooping eyelids, double vision, difficulty swallowing, limb weakness)
* strabismus = inability to FIXATE on same point with both EYES
* treatments = cholinesterase INHIBITORS and IMMUNOSUPPRESSIVE agents
66
**Neuromuscular Toxins and Paralysis**
* flaccid paralysis - muscles \_\_\_cannot \_\_\_
* curare: complete with ACH for receptor sites but do not ___ muscles
* ___ poison used by South American natives to poison BLOWGUN DARTS
**Neuromuscular Toxins and Paralysis**
* flaccid paralysis - muscles LIMP cannot CONTRACT
* curare: complete with ACH for receptor sites but do not STIMULATE muscles
* PLANT poison used by South American natives to poison BLOWGUN DARTS
67
**Neuromuscular Toxins and Paralysis**
* botulism - food poising caused by ______ secured by _____ clostridium botulinum
- ____ release of ACh causing flaccid \_\_\_
- ______ cosmetic injections for wrinkle removal
**Neuromuscular Toxins and Paralysis**
* botulism - food poising caused by NEUROMUSCULAR TOXIN secured by BACTERIUMclostridium botulinum
- BLOCKS release of ACh causing flaccid PARALYSIS
- BOTOX cosmetic injections for wrinkle removal
68
**Neuromuscular Toxins and Paralysis**
* toxins that interfere with synaptic function can ____ muscle
* some ___ contain cholinesterase \_\_\_\_
- bind to acetylcholinesterase, prevent it from ___ ACh
* tetanus (lockjaw) - spastic ___ caused by ___ from clostridium tetani
* - toxins blocks glycine (which normally inhibits spinal motor neurons); causes \_\_\_\_\_: spastic \_\_\_
**Neuromuscular Toxins and Paralysis**
* toxins that interfere with synaptic function can PARALYZE muscle
* some PESTICIDES contain cholinesterase INHIBITORS
- bind to acetylcholinesterase, prevent it from DEGRADING ACh
* tetanus (lockjaw) - spastic PARALYSIS caused by TOXIN from clostridium tetani
* - toxins blocks glycine (which normally inhibits spinal motor neurons); causes OVERSTIMULATION: spastic PARALYSIS
