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BIO201-Ch9-Muscles 2

BIO201 - Ch9 - Muscles and Muscle Tissue 2 - Marieb/Hoehn - RioSalado - AZ

Repolarization restores only the __ condition. Electrical
Na+ - K+ pump restores the __ condition. Ionic
Excitation-Concentration (E-C) Coupling Sequence of events - transmission of AP along sarcolemma leads to sliding of myofilaments.
Inside of sarcolemma is normally __ while outside is __. Inside=negative, outside=positive
Inside ion is __ and outside ion is __. Inside=K+ potassium, outside=Na+ Sodium
What restores ionic concentration in fiber? Sodium-potassium pump
Why is Ca2+ called the final trigger for contraction? Ca binding to troponin frees actin active sites to bind w/myosin heads.
T tubule's proteins (DHP receptors) are sensitive to __ & __ in response. Voltage - change shape
What are calsequestrin & calmodulin? Intracellular proteins that regulate calcium concentration.
Attachment of myosin head to actin requires __. Ca 2+
What causes rigor mortis? Cross-link of actin/myosin continues - no breath so no ATP synthesis. Can't exclude Ca.
If muscle tension develops but loan not moved, contraction is called __. Isometric (same measure)
If muscle tension overcomes load & muscle shortens, contraction is called __. Isotonic
Muscle tension measured in __ contractions & amount of shortening in __ contractions. Isometric - isotonic
Neuromuscular Junctions Chemical synapse between axon terminal - where neuron come close w/sk. muscle cell
Isometrically Contractingmuscle doesn't shorten
Isotonically Contracting muscle shortens & moves load - bicep curl.
Lengthening contraction Muscle lengthens due to load heavier than muscle tension - walking down stairs.
Motor Unit Muscle cells & all fibers it supplies controlled by a given motor neuron.
Temporal summation/wave summation Summing of several muscle contractions resulting in single, stronger contractions - signals in rapid sucession.
Tetany Near or at max temporal summation.
All-or-None Principle A motor unit contracts fully or not at all.
Stimulation of a single motor unit causes a weak contraction of the __ muscle. Entire
A graphic recording of contractive activity. Myogram
The response of a motor unit to a single AP of its motor neuron. Muscle Twitch
Every twitch myogram has __ distinct phases. 3 - (1) latent, (2) contraction, (3) relaxation.
Latent Period Muscle tension beginning to increase but no resonse on myogram.
Period of Contraction When cross bridges are active - myogram tracing rises to a peak.
Period of relaxation Muscle tension decreases to zero & tracing returns to baseline.
Unfused/Incomplete Tetanus Sustained by quivering contraction.
Fused/Complete Tetanus Smooth, sustained contraction plateau.
The force of contraction is controlled more precisely by __. Recruitment - multiple motor unit summation.
Recruitment process-size principle Allows increase in force in sm. steps & gradations in force are progressively greater when needed.
Treppe "Warming up" tracing pattern with staircase shape as slighly stronger contractions occur w/each successive stimulus.
2 Types of Isotonic Contractions Concentric & Eccentric
Concentric Contractions Muscle shortens & does work.
Eccentric Contractions Muscle generates force as it lengthens.
Which are more forceful - concentric or eccentric? Eccentric contractions are 50% more forceful.
Enzyme that catalyzes CP-ADP reaction? Creatine Kinase
When large amounts of ATP are needed in muscle, __ provides most ATP needed. Glycolysis
Which acid contributes to muscle soreness & fatigue? Lactic Acid
After 30 mins, __ becomes major source of fuels for oxidation. Fatty acids
Contractures Cramps - states of continuous contraction because cross bridges cannot detach.
Slow-developing fatigue damages the __ & interferes w/CA 2+ regeneration. SR
The liver converts lactic acid to __. Glucose or glycogen.
Force of muscle contraction affected by: (1) # of fibers stimulated, (2) fiber size, (3) stimulation frequency & (4) degree of muscle stretch.
The __ motor units recruited, the greater the muscle force will be. More
Regular exercises cause muscle cells to __. Hypertrophy - increase in size.
Internal Tension Force generated by crossbridges (myofibrils)
External Tension Force translated to load (muscle insertion)
Joints normally prevent bone movements that would stretch muscles __. Beyond their optimal range.
Muscles vary in how fast & how long they contract. Why? (1) Fiber type, (2) load & (3) recruitment.
What accounts for speed of contraction difference between slow & fast fibers? How fast myosin ATPases split ATP & patter of electrical activity of their motor neurons.
__ fibers rely mostly on aerobic pathways. Oxidative Fibers
Aerobic Respiration Requires oxygen as oxygen is final acceptor of electrons stripped from glycolyosis. Glycolyosis=>Krebs=>Electron Transport Phosphorylation. 36 net ATP/each glucose molecule.
Glycolysis Initial reaction for aerobic & anaerobic pathways - glucose broken down into 2 pyruvate & net of 2 ATP - occurs in cytoplasm - no oxygen - 2 NADH also form.
Pyruvate (pyruvic acid) Compound w/3-carbon atoms backbone - 2 are end product of glycolyosis.
Glucose+oxygen-->Carbon Dioxide+Water+ATP Molecular summary for Aerobic Respiration
NAD+ Nicotinamide Adenine - nucleotide coenzyme - NADH when carrying electrons & unbound protons (H+).
FAD Flavin Adenine Dinucleotide - nucleotide enzyme - becomes FADH2 when carrying electrons or H+
Naked protons Unbound hydrogen atoms (H+)
Substrate-Level Phosphorylation Direct, enzyme-mediated transfer of phosphate group - ADP/ATP
PGAL Phosphoglyceraldehyde - key intermediate in glycolysis.
Krebs Cycle Stage 2 of Aerobic Resp. - (Citric Acid Cycle) - Pyruvate broken down into CO2 & H20. 2 ATP, 8 NADH, 2 FADH2 forms.
Cristae Outter compartment - series of puches in Mitochondria where Electron Phosph. Trans. takes place.
Matrix Inner compartment where Krebs Cycle takes place.
Acetyl-CoA Coenzyme A w/2-carbon fragment from pyruvate - transfers oxaloacetate for Krebs Cycle.
Oxaloacetate 4 Carbon compound - point of entry for Krebs Cycle.
Electron Transport Chain Array of enzymes & cofactors taht accept & donate electron in sequence - H+ ions flow across & drive ATP formation.
Oxidative Phosphorylation Final stage of Aerob. Resp. - H+ & electrons sent through transport that gives up electrons to oxygen.
Anerobic Electron Transfers Used by bacteria & archaeans - uses plasma membrane & yet yield is variable but small.
Anabolism The assembly of small molecules into more complex ones.
Anaerobic Pathway Metabolic pathway - no oxygen.
Fermentation Anaerobic pathway of ATP formation. Glycolyosis & regenerates NAD+ - 2 ATP produced net.
Lactate Fermation - Muscles Pyruvate from glycolysis converted to lactate & NAD+ is regerated. Net 2 ATP - Cheese & dairy products.
Alcholoic Fermentation Pyruvate converted to ethyl alcohol or ethanol. Bakers use for bread.
Biosynthetic Pathway Metabolic pathway - sm. molecules assembled into lg. organic molecules.
Catabolism Metabolic activity. Breaks lg. molecules to components w/less energy.
Slow-twitch muscle fibers Make ATP by aerobic resp. & have many mitochondria - dark red.
Fast-Twitch muscle fibers Make ATP by lactate fermentation. Used for fast-short activity.
Fibers that rely mostly on anaerobic glycolysis are __. Glycolytic Fibers.
Which muscle fibers fatigue quickly? Fast glycolytic fibers.
The greater the load, the __ the latent period. Longer
The innervative nerve fibers of smooth muscle attach at __. Varicosities
Diffuse junctions can be found in synaptic cleft of __ muscles. Smooth
T tubules are absent in __ muscles. Smooth muscles (absent)
Smooth muscle depends on __ cellular Ca2+ for excitation-contraction coupling. Extracellular
Smooth muscles lack __ & __. Striations & sarcomeres
Smooth muscles have __ thick filaments. Less
Thick filaments in smooth muscle have heads __. Along their entire length & are as powerful as skeletal muscles of same size.
Troponin complex present only in __ muscle. Skeletal
Smooth muscles contract how? In a twisting manner like a corkscrew.
Dense Bodies Act as anchoring points for thin filaments in smooth muscle. Also bind cell to CT of endomysium.
What partly accounts for synchronous contractions of smooth muscle? Dense bodies transmitting force to CT.
What allows smooth muscle to contract together? Gap junctions.
Besides the heart, pacemaker cells can also be found where? In stomach & small intenstine.
__ & dense bodies of sm. muscle harness pull generated by crossbridges. Intermediate filaments.
Calcium binds w/__ in smooth muscles. Calmodulin - a cytoplasmic calcium-binding protein.
What phosphorylates myosin heads in smooth muscles? Mysoin Kinase
Another name for single-unit smooth muscle. Viseral muscle - walls of most hollow organs.
3 characteristics of single-unit sm. muscle. (1) contracts rythmically as unit (2) gap junctions (3) exhibits spontaneous action potentials.
3 examples of multi-unit smooth muscles. (1) Arrector pili, (2) internal eye muscles (pupil) & (3) lg. arteries.
Though multi-unit smooth muscle works like skeletal, it is served by the __ nerv. system. Autonomic (involuntary) - hormone controlled.
Muscle tissue develops from __. Mesoderm - myoblasts.
Satellite Cells Myoblast-like cells that help repair skeletal muscle fibers.
Duchenne Muscular Dystrophy (DMD) Most serious form of MD - sex-linked recessive disease.
Cause of DMD is a lack of __. Dystrophin
Sarcopenia Gradual loss of muscle mass.
Intermittent Claudication Restricted blood delivery to legs - painful.
In synaptic cleft of neuromuscular junction, __ is always pesent. Acetylcholinesterase
Only __ muscle cells branch. Cardiac
The time in which cross bridges are active is called the period of __. Contraction
Claudication might more simply be called __. Limping
__ (color) fibers are slow (oxidative) fibers. Red
A smooth, sustained contraction is called __. Tetanus
__ Contractions are stronger than concentric contractions. Eccentric
A nerve cell & all muscle cells it stimulates is called a __. Motor unit
A contraction in which muscle doesn't shorten but tension increased is __. Isometric
The gap junctions between smooth muscle cells are __ coupled. Electrically
Skeletal muscle cells are __ coupled. Chemically
__ smooth muscle is found in the intestines. Single-Unit
When muscle fiber contracts the __ band diminish in size. I band
During isotonic contraction, once the load is overcome, the contraction is __. Constant
Subunit __ actin bears active binding sites for myosin heads. G
From internal to external, connective tissue sheets of muscles are: Endomysium, perimysium, epimysium
Which muscle fiber contains abundant glycogen? Fast (oxidative or glycolytic) fatigable fibers.
Myosin filaments located in the __ band. A
Both actin & myosin found in the __ band. A - where they are found.
The __ band contains only actin filaments. I - only actin.
A sarcomere is the distance between two __. Z discs.
In muscle contraction, calcium acts to __. Remove blocking action of tropomyosin.
Muscle contraction differs in smooth & skeletal in that smooth __. Has a difference in the site of calcium receptors.
In isotonic contraction, the muscle __. Changes in length & moves the load.
T tubules function to __. Enhance cellular communication during muscle contraction.
After nervous stim. of muscle cell ends, calcium __. Levels drop in the cytoplasm.
Calcium ions bind to the __ molecule in skeletal muscle cells. Troponin
Created by: Ladystorm



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