Chapter 11- Muscular Tissue Flashcards
When there is a little bit of spring back of a muscle when contraction stops
Elastic Recoil
Thick filaments are larger and composed of ?
Myosin
Thin filaments are smaller and contains ?
Actin
A filamentous protein with elastic properties that helps to hold the thick and thin filaments together, also helps to attach them to the z discs and M lines.
Titan
Another important protein in skeletal muscle that helps attach the z lines of the sarcoma to scarcolemma via additional linking proteins
Dystrophin
The linking proteins, including dystrophin, are collectively called
Costameres
From one z-line to z-line is called ?
Sarcomere
The backbone of the thin filament is
G-actin
The long strands formed by the chain of balls is called
Filamentous actin (F-actin)
A protein that lies along the outside of the double-strand of F actin and covers up the myosin binding site on the G-actin molecules.
Tropomyosin
A protein that is a large globular protein with multiple sub units that is attached to the Tropomyosin and to the actin
Troponin
Controls the position of tropomyosin relative to the myosin binding site on the actin
Troponin
Composed of 2 heavy chains that coil to form the tail of the molecule and globular heads composed of parts of the heavy chains and 4 light chains
Myosin
Where thick filaments are
A band
Where thin filaments are not
H zone
Where thick filaments are not
I band
Contains ATP binding sites of this ATPase enzyme as well as the site that binds to actin
Myosin head
F Actin=
Chains
G- Actin =
Balls that form double strand
The movement of myosin heads towards the M-line while attached to actin
Power-stroke
The movement of of myosin heads towards the z-lines while unattached from actiin
Recovery stroke
During power stroke, what is released from the myosin ?
ADP
The magical ingredient that makes the actin binding site available
Calcium
Thin filaments overlap thick filaments, bringing z lines closer to m-lines as the i bands and h zones get smaller, shortening the sarcomere
Sliding filament theory
stiffness of death, the phenomenon used in forensics to help pinpoint time of death if a body is discovered within hours of dying
Rigor Mortis
The ____ becomes leaky long before the thin and thick filaments begin to break down
Sarcoplasmic reticulum
Breaks the bond between myosin and actin
binding of ATP
Consist of one spinal motor neuron and all the muscle fibers that it innervates
Motor unit
Are stimulated to contract by nerves
Muscle fibers
causes release of neurotransmitter into the synaptic cleft
Action Potential
Binding of the neurotransmitter to a receptor on the muscle cell stimulates
Cell contraction
The NMJ of The Synaptic knob contains secretory vesicles of the neurotransmitter
Acetylocholine
Action potential causes ____ to be released from the sarcoplasmic reticulum in the muscle cell
Ca++
The action potential thats in the nerve and the muscle cell
action Potential
Depolarization of the transverse tubules leads to opening of ____ on the sarcoplasmic reticulum
Calcium channels
When action potentials stop coming down the nerve, _____ on the motor end plate breaks down acetylcholine and closes the nicotinic cholinerigic Na+ channel
Acetylcholinesterase
As calcium levels drop, calcium will fall off of
Troponin
Comes from plants from south africa that binds nicotinic cholinergic receptor irreversibly and blocks receptor
Curare
” botox” , destoys SNARE proteins that help with release of ACh secretory vesicle, produced by the bacteria clostridium botulinum.
Botulinum toxin
Helps to maintain muscle tone by sending occasional action potentials leading to partial contraction of muscles
CNS
A response of single fiber to a single action potential
Twitch
The period where the interval between the action potential and the beginning of tension development
Latent period
The phase where The time required for full tension to develop
Contraction phase
The phases where time required for tension to fall to resting level
Relaxation Phase
(Contraction Strength of Twitches) Higher frequency =
stronger
(CSof T) Higher Ca++ =
Stronger
(CSofT) Length - tension relationship =
strongest
(CsofT) Warmed up =
stronger
(CsofT) Acidic pH =
Weaker
(CsofT) Dehydration =
Weaker
More APs occur before contraction is over , strength of contraction increases due to continued Ca++ availability
Summation
Repetitive stimulation (APs)
Tetanus
unfused or incomplete tetanus
Low frequency
Fused or complete tetanus
High frequency
failure of concentration after repeated stimulation at high frequency
Fatigue
Calcium pumps on the ??
sarcoplasmic reticulum
Na/K+ pumps on ???
Sarcolemma
Muscle cells have a small supply of oxygen because of the presence of a protein called
myoglobin
Creatine kinase and Myokinase are from what system ??
Phosphagen system
Found in most muscle cells, its release can signal muscle damage
Creatine Kinase
The loss of contractility after repeated stimulation
Muscle fiber fatigue
Fiber fatigue is associated with reduced ____ release from sarcoplasmic reticulum
Calcium
Progressive weakness and loss of contractility
Fatigue - muscle/body
Sprinter tend to have a more ___ fiber types in their legs
Glycolytic
Marathon runners tend to have a ____ fibers in their legs
Type 1
A protein that gives oxidative fibers a red appearance
Myoglobin
Low myosin , high oxidative capacity , slow oxidative fibers
Type I
High myosin , high oxidative capacity , intermediate speed , fast oxidative - gylcolytic
Type IIa
Highest myosin, high glycolytic , fastest speed
Type IIx or IIb
Fibers that are the largest in diameter
Fast glycolytic fibers
Fibers that are the smallest fibers
Slow oxidative fibers
Enlargement of muscle cells with use
Hypertrophy
Muscle wasting or shrinkage from lack of use
Atrophy
One neuron in a spinal cord and all the muscle fibers inner aged and controlled by that neuron
Motor unit
Neuron and muscle cells work together as a ___
Single unit
Resting tension in a while muscle is known as ___
Muscle tone
A phenomenon of whole muscle however not of individual muscle fibers
Motor unit recruitment
Recruitment is also called
Motor unit summation
Is the major way of controlling the tension generated by a muscle as whole to generate more or less tension as need
Recruitment
The muscle cells that Have a single nucleus but are branched , joined with demos ones and gap junctions at intercalated discs
Cardiac muscle cells
The muscles that Ca+ comes from the EVF rather than SR
Smooth muscle
myosin in smooth muscle is activated by
Phosphorylation
Which muscle Has dense bodies instead of Z lines ?
Smooth muscle
In smooth muscle , Multi unit muscle , each cell is ____
Innervated
In single unit smooth muscle, the nerve has ___ that function like nerve termina ls
Varicositites
Single unit smooth muscle cells are electrically connected via ____
Gap junctions
Much of smooth muscle is ____ unit muscle
Single unit
The nervous system that innervates smooth muscle regulates involuntary things are called
Autonomic nervous system
The muscle cell that do not have a motor end plate , but instead receptors for the neurotransmitters are scattered over the cell. What is this called ?
Diffuse junction
The myosin light chains are phosphorylated by the enzyme ____
Myosin light chain kinase
The enzyme , myosin light chain kinase, is turned on by the action of ___
Calmodulin
Once a action potential happens in smooth muscle, the Ca++ voltage channel opens in the ___
Sarcolemma , Cell membrane
A particular type of muscular dystrophy , due to a genetic mutation in the gene coding for the protein dystrophin that connects the muscle cell to the cytoskeleton to the sarcolemma and to the endomysium
Duchenne’s muscular dystophy
Autoimmune disease in which antibodies attack the aceylcholine receptors at the neuromuscular junction leading to their progressive loss over time
Myathesnia
