Exam 2 Prep Flashcards
Define permeability
The ease with which substances can cross the cell membrane
Cell membranes are _________ permeable
Selectively
Define passive transport
Cell doesn’t expend energy
Define active transport
Cell expends energy
Carrier mediated transport requires a _______
Transport protein
Diffusion is ________
Movement of a substrate from an area of high concentration to lower concentration
Give 3 examples of diffusion from lecture
-oxygen moves from lungs into blood, into interstitial fluid, into a cell
-CO2 moves from cells into interstitial spaces, into blood, out through lungs
-water moves across epithelium of digestive tract into body tissues
The lipid bilayer is ______ to O2 and ________ to most large molecules
Permeable
Nonpermeable
Define osmosis
Diffusion of water across a semi permeable membrane in response to solute differences
Osmotic pressure is
The force of water movement into a solution
Define isotonic
Equal concentrations, no net gain or loss of water
Define tonicity
The effects of various solutions on a cell
Define Hypotonic
Net gain of water into cell
Define hypertonic
Net water flow out of cell
Factors influencing diffusion
Faster diffusion if:
-short distance
-molecule is smaller
-higher temp
Concentration gradient is higher
Facilitated diffusion
-substance moves down concentration gradient
-requires transport protein
Co-transport facilitated diffusion
One substance moves down concentration gradient
-another substance moves against it’s concentration gradient
Active transport is ________ of concentration gradients and consumes _______
Independent, ATP
——— Na move out of a cell while _______ K into cell
3, 2
At rest cells have more ________ charge inside than outside
Negative
Resting potential sits at ______ mV
-70
Chemically regulated channels/Ligand gated channels do what?
Open or close when they bind specific Chemicals
Voltage regulated channels open or close in response to ________
Level of transmembrane potential
Example of chemically regulated channel
ACh gated sodium ion channel
-ACh binds to receptor on gated sodium channels in muscle membrane causing sodium channel to open
Define Depolarization
Trans-membrane potential becomes less negative
Define Hyperpolarization
Transmembrane potential becomes more negative
Define repolarization
Trans-membrane potential returns toward resting potential after being depolarized
Skeletal muscles attach to _______, are _______ and have _______ movement
Bone, striated, voluntary
Cardiac muscle is found in ______, are ______, and ________ movement
Heart, striated, involuntary
Smooth muscles line __________ are _________ and have __________ movement
Hollow organs, no striated, involuntary
Functions of skeletal muscles
(There are 6)
-produce skeletal movement
-maintain posture
-support soft tissues
-gaurd entrances and exits
-Maintain body temperature
-Nutrient Reserves
Skeletal muscles include
Skeletal muscle tissue, connective tissue, blood vessels, nerves
Define muscle origin
Attached to bone that remains relatively stationary during movement
Define muscle insertion
Attached to the bone that moves
The endomysium is the ________ layer and has what function
Innermost layer
Covers individual muscle fibers
The perimysium is the ______ layer and has what function?
Middle layer
Sheathes bundles of muscle fibers called fascicles
Contains collagen, elastic fibers, blood vessels, and nerve supply
The epimysium is the _________ layer and has what function?
Outermost layer
Surrounds a muscle
Contains blood supply, nerve fibers, muscle repair
Define deep fascia of muscles
Wrap groups of cooperating muscle together
Definition of a muscle cell
Muscle fiber
Define multinucleate
Hundreds of nuclei
Each muscle cell is as _______ as _______
Long
Muscle fiber
How are muscle cells first made in Embryogenesis?
end to end fusion of uninucleate myoblasts forming individual multinucleate skeletal fiber
Actin are _______ myofilaments
Thin
Myosin are _________ myofilaments
Thick
What are myofibrils?
Bundles of myofilaments
What is the Sarcoplasm
Muscle cell cytoplasm
What is the Sarcolemma?
Cell membrane of a skeletal muscle cell
What is the Sarcoplasmic Reticulum (SR)
Modified ER
The Sarcolemma conducts __________, have _______, and _________ with the SR
Action potentials deep into cells
Have transverse tubules (T tubes)
Comes into close contact with SR
The Sarcoplasmic Reticulum (SR) is _______ to the ER, forms a ______ around ______, and stores high concentrations of ______ ions needed for muscle contraction
Similar to the ER
Forms a tubular network around each myofibril
Calcium
In the SR terminal ______ form _____ with T tubes
Cisternae, triads
Two types of myofilaments
Thin (actin)
Thick (myosin)
Myofibril are ________ and are anchored to the inner surface of the ________ at either end
Bundles of myofilaments
Sarcolemma
Define I bands
Light bands containing only thin filaments
Define A bands
Dark band containing thick filaments and some overlap with thin filaments
Define H band
Contains only thick filaments
Define Z disk/line
Border between sarcomeres
Review the Sarcomere Structure
Thin filaments slide over thick filaments shortening the ________
Myofibril
Thin actin filaments attach to the ______ disk
Z
As a muscle contraction occurs
Thin filaments move towards the center of the ________
Thin filaments slide over _______
____ lines are pulled closer together
I bands and H bands _______
A band _______
Sacromere
Thick filaments
Z limes
Narrow
Stays the same
Is this sarcomere relaxed or contracted?
Relaxed
Is this sarcomere relaxed or contracted?
Contracted
How do thin and thick myofilaments slide across each other?
Myosin filaments bind to sites on actin forming cross bridges. Cross bridges then change shape using ATP to pull actin past myosin.
Interactions between myosin head and actin are prevented by _______ at rest
Tropomyosin
Strands of tropomyosin cover ______ active sites at rest
Actin
Myosin molecules have ______, ______ head, are golf clubbed shaped
Elongated tails, globular
Myosin heads form _______
Cross bridges
Actin strands are composed of _______ two row individual globular molecules
Twisted
Each actin molecule has a ______ to which a ______ can attach
Active site, myosin heads
Calcium is _____ around sarcomere at rest
Low
Sliding Filament theory/ cyclic process:
1 Calcium binds to ________
2 Troponin moves, moving ______ and exposing _____ active sites
3 _____ head forms cross bridge to ______, bending ______ center of sarcomere thus ______ the actin
4 ATP allows _______ of _______
1 troponin
2 tropomyosin, actin
3 Myosin, actin, towards, pulling
4 formation, cross bridge
Concentration of _____ around sarcomere controls ________
Ca, sarcomere contraction
Action potential in Sarcolemma and T tubes causes _______ channels of SR to open and release Ca into _______ and ________
Ca, Sarcoplasmic, sarcomere
When Ca levels _______ tropomyosin covers ______ sites ending contraction
Fall, actin active
Define motor neuron
Nerve cell that controls muscle contraction
Define neuromuscular junction
Synapse between motor neuron and muscle cell
As sodium ions flow into muscle cells it _______ the muscle cells membrane and starts an ______
Depolarize, action potential
Acetylcholinesterase (AChE) is located in ______ and rapidly breaks down _______
Synaptic gap, acetylcholine
Action potential along ______ causes release of calcium from _____ of SR
T-tubes, cisternae
Duration of contraction depends on
1
2
3
1 duration of stimulation
2 presence of calcium
3 availablity of ATP
Muscle relaxation requires ______
ATP
Steps that initiate a muscle contraction
(There are 5)
ACh released and binds
Action potential spread across membrane along t tubes
SR releases Ca
Calcium binds to troponin exposing active sites forming cross bridges after myosin binds
Contraction begins and is repeated
Steps that end a muscle contraction
(There are 5)
ACh is broken down by AChE
SR reabsorbs Ca
Tropomyosin return to covering active sites
Contraction ends
Muscle relaxes
Tension in a muscle depends on the _____ that develops in individual muscle cells during contraction and the ______ of muscle cells that contract
Tension
Number
Amount of tension depends on number of _______ formed
Cross bridges
Define a twitch
Cycle of contraction, stimulus, and relaxation produced by a action potential in a muscle cell
Latent phase of a twitch
Action potential occurs, no contraction until Ca is released from SR
Contraction phase of a twitch
Tension rises, Ca moves tropomyosin off actin actin sites, myosin cross bridges form
Relaxation phase of a twitch
Tension falls to rest, Ca pumped back into SR, actin sites covered, no cross bridge remains
Summation is?
Repeated stimulation produced before relaxation phase is complete
Complete tetanus
Maximum tension production in a muscle cell
Small motor unit has ______ control and innervates a _____ number of muscle fibers for a ______ contraction
Precise, small. Slow
Large motor unit has _____ movement control, and innervates a ____ number of muscle fibers for a ______ contraction
Gross, large, fast
Two types of Isotonic contractions
Concentric
Eccentric
Concentric contraction- muscle tension ______ resistance and muscle _____
Exceeds, shorten
Eccentric contractions- peak tension developed is ______ than the resistance, muscle _______
Less, elongates
Isometric contraction- ______ rises, muscle length remains ______
Tension, constant
Muscle cells must generate ______ at the ______ rate as it is used
ATP, same
Creatine Phosphate reserves _______ stored energy to convert _____ to ATP when _____ is needed
Release, ADP, ATP
Resting muscle fibers rely on _______ metabolism to generate ATP
Aerobic
Excess ______ is used to store glucose as _______ and create ______
ATP, glycogen, creatine phosphate
Anaerobic respiration converts pyruvate into _____
Lactic acid
Define muscle fatigue
A. muscle that can no longer preform at required level of activity
The recovery period rebuilds _____, _______ and _____ and recycles _______
ATP, CP, glycogen
Lactic acid
Types of skeletal muscle fibers
Slow fibers
Intermediate fibers
Fast fibers
Slow fibers take ____ as long to contract after stimulation, uses ______ metabolism with high ______ content
3x, aerobic, myoglobin
Fast fibers are large in diameter with large _____ reserves, use _______ respiration and ______ quickly
Glycogen, anaerobic, fatigue
Dark (red) muscles are mostly _____ fibers
Slow
Pale (white) muscles are mostly _____ fibers
Fast
Define hypertrophy
Increase in diameter of muscle
Define Atrophy
Decrease in diameter of a muscle
Define muscle spasm
Strong sudden usually painful
Define Muscle spasticity
Excessive muscle tone
Define muscle flaccidity
Very low muscle tone
Smooth muscle is present in ________
Almost all organ systems
Cardiac muscle cells are linked by _______ and _______ into functional syncytium
Gap junctions, desmosomes
In intercalated disks _______ provide structural attachment
Sarcolemma
Cardiac muscle contraction time are determined by ______ muscle cells
Pacemaker
Cardiac muscles rely on ______ metabolism with ____ myoglobin and mitochondria content
Aerobic, high
What are the results of aging on the muscular system?
Reduction in size, strength, and endurance of muscles
Skeletal muscles become less elastic
Botulism causes ______
Blockage of release of acetylcholine
Polio causes _______
Loss of motor neuron
Tetanus causes ________
Excessive stimulation of motor neuron
Inherited muscle disorders include _______
Muscular dystrophies such as Duchennes MD
Myotonic dystrophy is ________
Chromosome 19 disorder
