Exam 2 - Lecture Notes Flashcards
(3 main types of muscle tissue) skeletal- attached to bones/skin
striated: striped - distinct banded pattern throughout muscle; striation is incredibly …
muscles laid out from one … to another, have more or less … configuration
even;
joint;
straight
(3 main types of muscle tissue) cardiac:
striated- not in the same way as skeletal
laid out in … around the heart – causes some muscle fibers to go off at an angle
spirals
(3 main types of muscle tissue) smooth: doesn’t have ability to contract as … or as … as skeletal/cardiac muscle
quickly; forcefully
(3 main types of muscle tissue) smooth: present in .., …, and muscles that line major … in …–> tissues that respond to internal signals that one has no conscious control over
GI tract; bladder; airways; lungs
facial muscles tend to sag bc they are attached to other … rather than to bone
muscles
smooth muscle is about same size as …; contractile apparatus laid out in criss cross pattern, such that when it contracts it both gets less … and less ..
skin cell; wide; long
(muscle tissue) can become … and can then contract –> shortens in length
has ability to extend beyond resting length
can recoil on its own if its extended beyond a certain limit
flexibility per person is related to … of one’s muscles - innate feature, can’t be learned
excited;
extensibility
great deal of energy exerted to maintain …, but it’s not noticed because we’re used to it
body position
muscle stabilizes joints and … system
most complex joint system is that of the …
skeletal;
knee
muscles allow for heat generation via shivering:
only source of generating … for humans
additional heat
“white” pieces around muscle is mostly
protein
in direct muscle attachment there is typically no need for muscle to extend all the way to the …; can actually be hindrance
end of the bone
fingers are entirely … - no …
tendons; muscle
there are muscles in palms
muscles in forearm extend … up through to fingers –> using forearms when …
indirect tendons up through to fingers;
moving fingers
(muscle tissue) epimysium contains all of the …, …, …, etc
blood vessels; nerve fibers; connective tissue
muscle fibers can be very …, but they are very long
skinny
muscle cells have multiple nuclei, because as they are developing, muscle cells are … to form long, single cell that is multinucleated
fusing together
difference between myoglobin and hemoglobin is that myoglobin only has …, whereas hemoglobin has …
tertiary structure; quaternary structure
sarcoplasmic reticulum is not concerned with …; there as storage
protein construction
myofibril:
appearance of dark and light striations are result of how underlying architecture is laid out bc skeletal muscle uses two … elements to facilitate contraction
cytoskeletal
myofibril:
dark bands are there bc of presence of myosin- found in other cell types as single molecule, but in skeletal muscle they band together to form very …, … … structures
thick, stiff ropelike
myofibril:
light band: consists of actin; when shining light through it, more light goes through because actin fibers are
thin
myomesin makes up M line in sarcomere:
… such that they cannot move independent of one another –> keeps them lined up
holds thick filaments in place
I band spans from end of one … to the beginning of another …
thick filament; thick filament
thick filaments anchored to Z disc by protein called … –> acts like a …
titin; spring
when individual muscle fibers are stretched, … allows them to return to their original shape
otherwise thick and thin filaments would slide past one another and wouldn’t be able to return back to original configuration
differences in … of this protein can be responsible for variations in flexibility
titin;
elasticity
H zone slightly lighter than … but not as light as ..
A band; I band
myosin in muscles have very long .., unlike in other cells, and these wind around one another
… at end
… that walks along actin
tails;
myosin head;
motor protein
myosin:
works by …
organized in a fashion such that on one side of the M line all of the heads are … and on the other side the heads … – such that during contraction both sides move towards the …
hydrolyzing ATP;
pointing in one direction;
point in the other direction;
midline
actin is a polymer:
if it is not polymerized it is called … 0 …
G actin; globular actin
when actin … it forms twisted filament called f actin
G actin doesn’t stack perfectly evenly – when they associate, they associate at an angle so that they twist to forma. spiral - spiral enables action of … and …
polymerizes; tropomyosin; troponin
(tropomyosin) if muscle is not actively contracting, this protein mimics … to block myosin binding sites
troponin keeps tropomyosin in such a position that by its … nature, it completely obscures all of the actin-myosin binding sites - …
spiral;
complementary spiral nature; reinforcer
(tropomyosin) for contraction to occur, troponin has to undergo … so it pulls tropomyosin in different direction that changes … of spiral and slides it away from myosin binding sites
conformational change;
pitch;
SR resembles SER more than RER
no …
form … that isn’t really organized
when muscle wants to contract, this opens up and “dumps” calcium onto entire muscle fiber - does so as evenly as possible
embedded ribosomes;
webbing
SR:
terminal ends of SR adjacent to …, which carry the electrical signal for muscle fiber contraction and when it reaches SR< this organelle has … on it that change shape to allow for exit of Ca2+
T tubules;
voltage-gated receptors
T tubules are continuous with sarcolemma - … of sarcolemma that extend into interior of muscle fiber
allows for more … contraction of muscles
invaginations;
coordinated
without T tubules, muscle contraction would be …, not … and …
jerky; smooth; even
SR has plates at end called … which are responsible for communicating signal from … to …
terminal cisternae; T tubule; SR
voltage sensitive proteins in T tubule change … and push on proteins in those terminals, i.e. … proteins
shape; foot
foot proteins then change shape and opens … and calcium rapidly rushes out of interior of SR and into … of muscle
calcium channels;
cytoplasm
… contraction: can generate force but not actually move muscle
shortening only happens when generate enough attachments to … to exceed force that’s actually generating them
isometric; thin filaments
sliding filament model of contraction:
when contraction occurs, all sarcomeres shorten such that there are huge amounts of .. between the two filaments
… doesn’t move, stays in place but pulls actin filaments towards M line, sliding them past thick filaments
overlapping; myosin
… shorten when contraction, but … do not change length
sarcomeres; filaments
… do not ever shorten, they are just moving closer together
.. disappears during contraction: no longer center space where there are no … filaments
thick and thin filaments;
H line;
actin
…: bundle of axons in PNS
nerve
neuromuscular junction in middle of each fiber:
coordination of contraction more even
otherwise muscle tissue would develop … and potentially lead to …
unevenly; muscle tears
… is the muscle part of the neuromuscular junction and contains ACh receptors
postsynaptic endplate
when ACh is released into synaptic cleft it can either be … or become broken down by an enzyme that is constantly released into synaptic cleft - …
reabsorbed; acetylcholinesterase
action potential in muscle:
delay for slow voltage gated potassium channels is much … than in neurons, because muscle contractions takes longer than sending an action potential down a nerve
… also takes longer
longer;
refractory period
change in voltage triggers opening of calcium gated channels, calcium will bind to proteins on the …
synaptic vesicles
synaptic vesicles will line up in a “neat, orderly line” - those that are ready to be released are … at the plasma membrane
calcium binds to proteins that keep the vesicles docked - … (these proteins capture the vesicles and hold them by the plasma membrane)
docked;
SNAREs
calcium present in extracellular fluid in high concs. - no … because Ca2+ is so universal in its function that we want to maintain tight control over it
calcium leak channels
synaptic cleft is small so Ach … - this is the initiation of the action potential
diffuses instantly
ion disturbances that occur through release of calcium ultimately results in …
two …
this process is slower bc the amount of space being covered is much larger as compared to neurons
excitation-contraction coupling;
latent periods
… channels spread evenly throughout sarcolemma
voltage sensitive sodium
action potential travels down length of sarcolemma in both directions both … and also in both directions across the …
lengthwise; circumference
… are embedded in the sarcolemma. these are not ion channels. act as … When voltage disturbance comes along, the protein changes shape and pushes on ion channels that are embedded in the sarcolemma
voltage-sensitive tubule proteins;
molecular levers
voltage-sensitive tubule proteins:
terminal cisterna of SR have … sensitive calcium channels, and the voltage sensitive levers push on these and … them, pushing them open
pressure;
deform
voltage-sensitive tubule proteins:
calcium rapidly floods out of SR and into the cytoplasm of the cell –> all the action will then occur at level of … - rapid diffusion of calcium throughout the sarcomeres
sarcomere
voltage-sensitive tubule proteins: calcium ions will bind to …, facilitating movement of tropomyosin to expose active sites such that the myosin heads on the thick filaments can bind to binding sites on the actin filaments, creating a …
troponin;
cross-bridge
cross-bridge: physical joining of … in thick filament ot … on filamentous actin
myosin head; myosin binding site
when not contracting, intracellular calcium concs are
low
… and … pop off when myosin binds so that it can change shape and pull thin filaments towards M line
ADP; Pi
regeneration via creatine phosphate - direct phosphorylation
facilitated by …, which sticks as phosphate onto creatine
creatine kinase
muscles store creatine phosphate:
the amount that muscles hold can be increased - through …, will be absorbed into muscles
but total amount that can be absorbed gives at most … of ATP
supplements; 4-6 s
increased … leads to increased “muscle size” - it’s not more muscle …, it’s increased … tissue
vasculature; tissue; circulatory
exercise strengthens …, training muscles to have more … per contraction as compared to prior to working out
neuromuscular junctions;
cross bridge cycles
forming cross bridge cycles with at best 40% of available myosin heads in thick filaments - this is because tends have to grow as well when muscles do, and tendons gain strength at … the speed of muscles, so if 100% of myosin heads were used, you’d increase the risk of …
1/8th;
tearing tendons
steroids allow for muscles to … more quickly, doesn’t cause muscles to … more quickly
recover; strengthen
at …, ATP has been burned through and ATP supply depends on glycolysis leading to lactic acid buildup
70% of maximum contractile activity
smaller changes in muscle size primarily due to increased …, but over years, actual … amounts can be increased
vasculature; muscle fiber
net gain of … ATP/glucose through aerobic respiration
32
muscle fatigue occurs due to ionic imbalances (caused partly by …) - contraction becomes …, start getting … and … - not getting full … at end plate
sweating; jittery; spasms; cramps; action potential
total lack of ATP rarely occurs - only when you’re … –> …, this state only ends when muscle begins to degrade
dead; rigor mortis
…% of energy investment is lost as heat - inefficient process
… allows for heat dissipation
60; sweating;