Exam 3 Flashcards
Transduction
taking a sensory stimulus and converting it into an action potential, made possible through sensory receptors of different kinds
What signal does the nervous system understand
an action potential
Signal transduction systems
some first messenger outside of the cell changes or leads to something in the cell such as some protein kinase activity
Mechanoreceptor
receptor that responds to a mechanical stimulus
Chemoreceptor
receptors that respond to a chemical stimulus
Noiceptors
change chemical signals in the environment that indicate there’s damage to other tissues
Prostaglandin and potassium
are primary chemical signals nocieptors pick up on, potassium is in high concentration inside the cell so when the cell is lysed open the nocieptors will detect the potassium
Photoreceptors
receptors that respond to a change in activity of rods and cones
Sensory receptive field
an area of internal/external environment that a sensory receptor responds to, there’s an overlap of receptive fields of sensory receptors and the field is variable in size
Sensory receptors
produce receptor potentials which are graded potentials that may or may not lead to an action potential
Sensory receptors specialized endings
they will change the activity of the cell leading to change in activity of the CNS, most nervous system cells are like this as are most nociceptors
Specialized endings
pick up a stimulus or stimulus energy and act on an individual cell which will then signal another cell
Sensory neuron cell body in the CNS
will send out a process to the periphery that will receive to some part of the skin, free nerve endings radiate in the skin and will pick up on pain signals
Sensory neuron cell body in the periphery
will change the activity of another neuron which will then signal to the CNS, as seen with the eyes
Receptor potential
graded potentials, that may or may not lead to an action potential if the graded potentials summate and reach threshold
When will graded potentials and receptor potentials be recorded in a sensory neuron
before myelination starts, myelination will start at the axon hillic and everything before then is a graded potential (EPSP/IPSP), after receptor potentials the action potentials will be recorded in the nodes of ranvier starting at the first node of ranvier
Stimulus intensity and receptor potential and action potentials
as the stimulus intensity increases the receptor potential amplitude will increase as graded potential amplitude is dependent on the amount of stimulus, an increase to stimulus intensity the frequency of action potentials increase
Pressure and action potentials
the brain can distinguish between the amount of pressure on the skin based on the frequency of action potentials
Principles of sensory system organization
specific sensory receptor types are sensitive to certain modalities and submodalities, specific sensory pathways code for a particular modality or submodality, specific ascending pathways are crossed so that sensory information is generally processed contralaterally, the thalamus is the brain’s sensory relay station, specific ascending pathways are subject to descending control
Exceptions to contralateral control
vision and gustatory
Thalamus
all sensory information except the sense of smell will go to the thalamus first and after it will go to specific cortical areas
Ascending vs Descending
ascending is sensory and descending is motor as seen in the cross extensor reflex
Cross extensor reflex
if you were to step on something you have to lift your foot up and the quadriceps of the other leg has to tense up
Visible light spectrum
400nm to 750nm, as wavelength increases energy decreases, as approach blue the energy increases
Eye layers
sclera, choroid, retina
Sclera
outside layer, the white of the eye, the connective tissue
Cornea
the transparent continuation of the sclera as the anterior portion of the sclera bulges, non vascularized (if it was vascularized we’d see pink and red), consists of layers of translucent epithelial cells
Anterior chamber
between the cornea and the iris, holds aqueous humor
Aqueous humor
fluid which will give oxygen to the cornea through diffusion, more viscous than plasma of the blood
Posterior chamber
between the iris and the lens, holds aqueous humor
pupil
opening that allows for movement of fluid between the posterior chamber and the anterior chamber
Iridocorneal angle
where the cornea and the iris meet
Canal of Schlemm
small duct that connects with vasculature allowing aqueous humor to/from the anterior chamber, promotes circulation of the aqueous humor
Glaucoma
the blocking of the canal of schlemm such that the aqueous humor is unable to move from the chambers and enter the vasculature leading to intraocular pressure building
Lens
behind the iris and in front of the posterior chamber, avasculur, flattened translucent epithelial cells, connected to zonular fibers, is a circular structure
Zonular fibers
also known as suspensory ligaments or fibers of zonn, extend from the lens and connect to ciliary muscles
Ciliary muscles
also known as ciliary bodies smooth muscle extensions of the choroid
Choroid
Middle layer, vasculaturized, vessels are visible through the sclera
Eye drops
vasoconstrict the vessels found within the choroid to reduce redness of the eyes
Vitreous chamber
in the back of the eye containing vitreous humor, holds the retina in place and provides oxygen and glucose to avascular structures
Retina
bowl of cells that cover the back 2/3 to 3/4 of the eye, ganglion cells exit in the form of the optic nerve to send information to the SNC and other parts of the brain
Fovea Centralias pit
found in the center of the retina, within it is the macula ludea (yellow spot) is the area with the most acute vision
Macular degeration
loss of cells that respond to light found within the macula ludea
Blind spot
also known as the optic disc, there’re no photoreceptor cells here
Diabetics and eyes
opthamologists will want to see the vasculature of the eyes because micro aneurisms can develop leading to hemorrhage and the cells of the retina could become ischemic leading to the detachment of the retina
First layer of the Retina
retinal pigmented epithelialium layer, dark pigments will absorb stray wavelengths of light, epithelial tissue that connects the retina to the choroid
Low energy wavelengths
are harmful and when they aren’t picked up by photoreceptors in the retina they are picked up by the dark pigments within the RPE
Second layer of the Retina
Photoreceptive layer, rods and cones, photoreceptors imbed themselves into the epithelial aided by cilia as the epithelium is heavily ciliated
Third layer of the Retina
Outer limiting membrane, not a membrane but an artifact of photoreceptor extensors as it makes its way to the epithelial, when the retina is stained it appears as if there’s a line here due to photoreceptor extensions of cell bodies (rod/cone shaped) exit the cell body, all of the parts of the cell except the receptor are similar in shape,
Fourth layer of the Retina
cell bodies of rods and cones, very defined shapes of the rods and cones
Fifth layer of the Retina
Outer plexiform layer, connections/synapses between photoreceptors and other types of cells found in the retina, very lightly stained area
Sixth layer of the Retina
Inner nuclear layer, made of mainly bipolar cells, horizontal cells, and amacrine cells
Bipolar cells
have two processes that extend off the cell body
Ratio of photoreceptor to inner nuclear cell to ganglion cell
is not 1:1:1 as there’re intricate connections of the cells in the inner nuclear layer to other cells
Seventh layer of the Retina
Inner plexiform layer, connections/synapses between inner nucleon layer with ganglion cells
Eighth layer of the Retina
ganglion cell layer
Ninth layer of the Retina
Optic nerve fiber layer, axons from the ganglion cells will exit the eye in the form of an optic nerve
Tenth layer of the Retina
Inner limiting membrane, thin layer of epithelial cells htat are in direct contact with the vitreous humor/body
Accomodation
the ability of the lens to change shape to focus light onto the back of the eye
Look at an object in the distance
ciliary muscles are relaxed giving tension to the zonular fibers which pulls on the lens to stretch or flatten
Look at an object close up
the parasympathetic nervous system activates the ciliary muscles which slackens the zonular fibers leading to the lens being more rounded or football like
Near point of Accommodation
for normal 20-23yr old’s it is about 10 cm away and increases with age
Gmmetropica
normal vision, light comes in and hits the retina at a focal point, 20/20
Myopia
near sighted, light comes to a focal point before the retina, due to failure of accomodation of the lens or the eye is too long, corrected with divergent/concave lens to spread the light out, 20/(<20)
Hypermetropia
far sighted, light comes to a focal point behind the retina, corrected with a convergent/convex lens, due to failure of accomodation of the lens or the eye is too short, as you age you become presbyopia (hypemetropia)
Amblyopia
lazy eye due to damage of extraocular muscles
Rods and Cones
Rods are primarily located toward the periphery while cones are in the center of the retina, there’s an overlap of receptors, there’s one type of rod and three types of cones, there’re more rods than cones (120mill rods:6mill cones), rods are more sensitive to light than cones, cones allow to see in color and rods see in shades of grey
Light and photoreceptors
light comes in through the pupil and passes through the retinal layers and change the firing rate of photoreceptors who will then communicate with those in the inner nuclear layer which will communicate to the ganglion cell layer and send information out via the optic nerve to move the signal into the brain, photoreceptors respond to a distribution of wavelengths
Dark current
photoreceptors maintain a dark current when there’s no light, the photoreceptors are depolarized (sodium and calcium channels are kept open by cGMP created by guanylyl cyclase), bipolar cells are inhibited and membranes are hyperpolarized, glutamate will be released and bind onto metabotrophic receptors to promote hyperpolarization of ganglion cells by primarily opening potassium channels thus inhibiting the ganglion cells and therefore the axons from the ganglion cells will not send signals to the brain
Photoreceptors in the light
Tranducin will undergo a conformation change into retinal which will then be imbedded into opsin, the g protein will be activated by the conformation change and activate cGMP dependent phosphodiesterase which will break down cGMP to GMP, calcium and sodium channels will then close and the membrane will hyperpolarize, bipolar cells are disinhibited and depolarized, ganglion cells are activated and axons send signals to the brain
Tranducin
g protein coupled receptor, ligand dependent
Retinal and Opsin
collectively they are a photopigment within the photoreceptors called rhodopsin, retinal is essentially vitamin A
cGMP dependent Phosphodiesterase
can be inhibited by caffeine
Phosphodiesterase
is a huge family of enzymes with numerous types, in the peripheral nervous system it can lead to changes in diameter of blood vessels
Sildenafil citate
commonly known as viagra, originally used to treat high blood pressure and has a side effect of sudden decrease or loss in vision of one or both eyes, it is a phosphodiesterase inhibitor, it was made to interaction with periphery phosphodiesterases but because there’re multiple types of phosphodiesterases it also interacted with phosphodiesterases found more centrally, within the eye leves of cGMP remain high and therefore the photoreceptor remains depolarized
Lateral geniculate nucleus
six layers of cells that are bent in the shape of the knee located away from the midline of the thalamus
Two halves of the retina
temporal hemiretina and nasal hemiretina, nasal hemiretina axons are contralateral while temporal hemiretinal axons are ipsilateral, the L temporal hemiretina and R nasal hemiretina gathers information from the R visual field
Optic tract damage
you won’t be able to see one side of the visual field
Optic chiasm
after the cross are the optic tracts, the suprachiasmatic nucleus of the hypothalamus is right above this point, and the pituitary gland is right below and slightly towards the right
Glandular components
the hypothalmus and the pituitary gland are glandular components mainly associated with the endocrine system
Adenoma
benign growths of grandular tissues
Hyperclasisticity
increase in size and number of cells which make prolactinoma within the pituitary which causes a prolactinoma the most common adenoma
Prolactin
causes cells of the mammary glands to produce milk in femles and controls LH and FSH levels and the menstrual cycle, within men it effects testosterone production and sperm production
Prolactinoma
causes pressure on the nasal hemiretinas in the chiasm and can lead to tunnel vision
Males and prolactinoma
males are more likely to end up with tunnel vision due to them not being able to see the effects of an increase of prolactin and therefore the prolactinoma goes unnoticed
Women and prolactinoma
they are more likely to notice the prolactinoma at an early stage due to being able to see signs such as irregularities of the menstrual cycle
Cranial nerves
either sensory, motor, or mixed, all cranial motor neurons have nuclei at some point in the central nervous system, the numbering is dependent on the position anterior to posterior on the ventral surface of the brain
Cranial nerve I
Olfactory, sensory only, axons travel through holes in the cribbiform plate of the ethmoid (this is the olfactory nerve), carries input from receptors in the olfactory neuroepithelia
Cranial nerve II
Optic, carries input from receptors in the eye, sensory only
Cranial nerve III
Oculomotor, controls movements of the eye via skeletal or smooth muscles, found in the mid brain, motor only
Cranial nerve IV
Trochlear, controls movements of the eye via skeletal or smooth muscle, motor only
Cranial nerve V
Trigeminal, controls muscles of the jaw and indicates tooth pain, mixed
Cranial nerve VI
Abducens, ontrols movements of the eye via skeletal or smooth muscle, found in the pons, motor only
Cranial nerve VII
Facial, contracts muscles of the face, involved in taste, mixed
Bell’s palsy
droopiness of one side of the face due to inactivity of cranial nerve VII
Cranial nerve VIII
Vestibulocochlear, sends information from the inner ear regarding auditory, balance, and acceleration, sensory only
Cranial nerve IX
Glossopharyngeal, involved in taste, controls muscles of the throat and larynx, mixed
Cranial nerve X
Vagus, goes everywhere within the throax/abdomen, mixed
Cranial nerve XI
Spinal acessory, neck muscles, sensory only
Cranial nerve XII
Hypoglossal, moves the tongue, sensory only
Cortex and sense
there’re areas of the cortex which are specialized for each sense
Semicircular canals
sit in the three major planes of the inner ear, filled with endolymph fluid, important for dynamic equilibrium (acceleration)
Ampulla
found at the base of each semicircular canal, inside are hair cells that sit on and within a layer of supporting cells, the hair cells have projections called sterocillia which sits in the cupula and the cupula will attach to the ampulla wall
Dynamic equilibrium
acceleration detected by the inner ear
Endolymph fluid
moves opposite to the body but in the same direction within both ears, will put pressure against the cupula such that the sterocilla will move to open/close channels
Sterocillia
has tip links with potassium channels on it, when they are open they will depolarize the cell and release a neurotransmitter when the potassium channels are closed the cell is hyperpolarized
Hair cell activity
is never off but the intensity and frequency of the signaling changes based on the stimulus
Vestibularocular reflex
motion sickness/dizziness accompanied by nausea
Smooth muscles of the eye
lateral rectus and medial rectus, rectus refers to the fiber direction, when the medial muscles contract the eye moves inward, the lateral muscles contract the eye moves outwards, the lateral rectus is controlled by cranial nerve four and medial rectus is controlled by cranial nerve three which receives synapses from cranial nerve VI
Vestibular nerve
from the sensory neurons, will make their way to the medulla oblongata found in the brain stem
Vestibular nucleus
controls the reflex, part of the medulla which will cause us to throw up, they send axons to the abducens nucleus on the contralateral side
Over activity of the hair cells
if there’s constant acceleration then the endolymph will constantly move the hair cells, the over activity of the hair cells can effect how the eyes see particular movement such that they cannot compensate properly and therefore you experience the visual field spinning
Alcohol
makes the endolymph less viscous such that it moves all around the place
Static equilibrium
how the body determines orientation of itself in space; specifically the head, use the saccule and utricle
Saccule and Utricle
there’re supporting cells which hold sterocillia which sit in a gelatinous layer called an otolith, there’re also little precipitated calcium salt rocks known as otoccnia
Otolith
when the head moves gravity will pull the otolith and move the tip links to open/ close channels
Earwax
cerumen, made from cerumonous glands
Cochlea
comes from a greek term meaning snail, cylinder that is rolled upon itself a few times, three chambers, filled with a fluid called perilymph
Ear parts
external ear, middle ear, inner ear made of two sets: semicircular canals and the saccule, uticle
Pinna
also known as the auricle are the ear parts on the outside of the head that will funnel soundwaves through the external auditory canal that will pass through the temporal bone in a temporal lining of the meatus
Tympanic membrane
also known as the ear drum, is highly vascularized
Otitis media
middle ear infection, when you swallow and it hurts teh ear its due to inflammation and infection traveling through the pharnx to the middle ear
Three parts of the pharynx
nasopharynx, oropharynx, and laryngopharynx
Nasopharynx
behind the nasal cavity, connected to the middle ear via the auditory tube (also known as the eustacian tube or pharyngotympanic tube),
What happens when sound waves enter the ear
they come in through the external auditory canal, makes the tympanic membrane vibrate and due to the vibration it will lead to the components of the middle ear to vibrate
Tympanic membrane and pressure
in order for the tympanic membrane to vibrate the air pressure on both sides have to be equal, the tympanic membrane will bulge depending on which side the pressure is the greatest
Ossicles
three tiny bones within the ear connected to the tympanic membrane, referred to as the malleus, incus, and the stapes (hammer, anvil, and stirrup), when the tympanic membrane vibrates the stapes acts like a piston that pushes into the membrane of the cochlea called the oval window
Oval window
when it moves it causes the perilymph to move and cause the scala vestibuli duct then around the helicotrema and then through the scala tympani eventually pushing against the round window
Basilar membrane
separates the choclear duct from the scala tympani and then will vibrate a t afrequency and amplitude to activate eh hair cells
Organ of corti
layer of hair cells and membranes within the basilar membrane
Frequency hair cells location
high frequency located near the round window and those that respond to lowest frequencies are found in helicotrema, low frequency hair cells can be found near the helicotrema
Why an ossicle system
it’s inefficient to move soundwaves from an air medium to a liquid medium therefore the ossicles amplify the sound waves from a gas medium such that the liquid medium within the cochlea will be able to transduce them
Skeletal muscle cells
connected to the bone and involved in voluntary movement, long and cylindrical, made of contractile elements, can be up to 20cm in length and 10-100, multinucleate, could have 50 nuclei, nuclei are found in the periphery, striated, arranged in parallel rows, amitotic
Contractile elements
smaller cylinders which are specialized organelles that make up the skeletal muscle cells
Strength and skeletal muscles
an individual muscle could be made of multiple cells the stronger you are the larger the diameter of the cell
Cardiac muscle cells
straited, either binucleate or uninucleate
Intercalated disc
cardiac muscle cells that branch with junctions between each muscle cell
Smooth muscle
spindle shaped, arranged in sheets, uninucleate, involuntary
Where is smooth muscle found
hair follicles of the skin, eye, lining of tracts
Fasicles
muscle fibers that are bundled together also known as a muscle cell
Myofiber
specialized organelle in straited muscle consisting of alternating bands of light and dark
Sarcolemma
skeletal muscle cell membrane
T tubules
transverse tubules, at each z line the sarcolemma will fold inward, a downward projection of the sarcolemma to inside the muscle cell, wraps around individual myofibruals, increases surface area for more receptors for acetylcholine
Sarcoplasmic reticulum
the ER of muscle cells, but dissimilar to the ER the structure is that of pouches and sacs
Lateral sacs
expansions of the sarcoplasmic reticulum
T tubules and sarcoplasmic reticulum
they are connected to each other such that if there’s a change in the membrane potential of the sarcolemma it will spread along the entire length of the muscle cell as well as through the muscle cell
Sarcomere
function and structural unit of muscle contraction bordered by a Z line/disc on each side, made of a collection of proteins
Actin and myosin
primary proteins of a sarcomere, their relationship gives the muscle the striated look
Actin
thin filament, globular protein, polymerizes with other actin, has binding sites for myosin cross bridges
Tropomyosin
weaves around actin covering the binding sites when the muscle is relaxed
Troponin
holds tropomyosin over the binding sites of actin, has three binding sites: one for tropomyosin, another for actin, and another for calcium
Myosin
thick filament, has two polypeptide heavy chains and four light chains,
Light chains
have globular heads containing cross bridges which have binding sites for actin and ATP, when the cross bridges on the globular head hydrolyze ATP it will provide energy for force generation
ATP with muscle contractions
causes cross bridges to move by hydrolyzing, needed in relaxation of muscles as it binds to cross bridges to cause it to let go, moves calcium against its gradient with calcium ATPase
Distrophin
anchors myofibrils to the outside membrane giving muscle cell strucutre
Muscular dystrophy
X linked recessive disorder where there’s a mutation to distrophin such thatt the myofibrils are no longer anchored ot the outside membrane and the muscle starts to lyse
Bands of the sarcomere
I band, A band, H zone, and M line, each band varies in how much light can pass through, name refers to german words
H zone
only myosin, has supporting protein (M line) that goes right down the middle
A band
actin and myosin overlap, the overlap is the length of myosin
I band
only actin, bisected by the Z line
How many actin surround myosin? and vice vers?
there’re 6 thick filaments that surround a thin filament and three thin filaments to surround a thick filament
What has to occur for muscle contraction
calcium levels within the muscle cell has to go up, calcium is in higher concentration in the extracellular space, calcium can also be found within the sarcoplamsic reticulum and mitochondria
How did people before the 1950 believe how muscles contratcted
calcium binds to myosin and changes its shape so that it gets shorter, they knew of cross bridges on myosin, thought all cross bridges were connected to actin all the time and that when calcium shortened the myosin and pulled actin towards the H zone forcing all zones to shrink
Sliding filament history
founded by Huxley who published a paper in Nature around the 1950s, used an electron microscope and a ruler
Sliding filament experiment
sarcomeres were imaged in the relaxed state and then in a contracted state and measure the components of the sarcomere
Sliding filament experiment results
Z lines would get closer to each other, I band and H zone are reduced in size while A band remains the same size
Sliding filament conclusion
in contracted and relaxed muscle myosin remained the same length therefore myosin stays the same shape and actin slides over myosin pulling actin towards the middle
Cross bridge cycling
myosin will hold onto actin and pull it towards the H zone but there’s no recoil of the actin due to cycling, cross bridges at various points will pull and then one cross bridge will let go while the adjacent cross bridges stays holding on, this cycling will continue as long as calcium is around
Cross bridge cycling frequency
is dependent on the strength of the muscles contract, the higher the strength of contraction the larger amount of cycling and then sustaining, does not change the amplitude of an action potential but rather the frequency of the action potential
Acetyl choline
necessary skeletal neurotransmitter, released by a motor neuron
Motor unit
motor neuron and all the muscle cells that it makes it contact with
Ratio of motor neuron to muscle cells and ratio of muscle cell to motor neuron
one motor neuron can innervate with thousands of muscle cells but one skeletal muscle can innervate with one motor neuron
Fine movement vs gross movement
the smaller the ratio of motor neuron to muscle cells leads to fine motor movement while larger ratios of motor neurons to muscle cells will lead to gross movements
DHP receptor
dihydropuridine receptor
Sarin nerve gas
inhibits acetyl choline esterase so that acetyl choline will stay in the clef and the skeletal muscle cell will continue to produce an action potential allowing for increased calcium concentrations within the cell and continual cross bridge cycling and muscle contraction
Neuromuscular junction
where motor neuron and skeletal muscle cell interact, the axon terminal has a large surface area and claw like extensions
Motor end plate
portion of the skeletal muscle cell that receives information from the motor neuron
Schwann cell
glial cells which surrounds the axon terminal to insulate the axon terminal and the end plate from the extracellular fluid
Resting potential and threshold potential of skeletal muscle cell
-90 mv resting and -75 threshold potential
End plate potential
generated by a motor endplate, is a graded potential similar to EPSP, due to ligand gated ion channels (acetylcholine receptors), only produces an depolarization due to sodium channel linked to acetylcholine receptors, depolarization will occur in the middle of the skeletal muscle cell where the end of the motor neuron is and then the action potential will move in both directions of the muscle cell
Why won’t the depolarization of a muscle cell go back to where it started
due to the voltage gated calcium channels being closed and needing to be inactivated before opening again
Latent period in skeletal muscle contractions
10 ms
Resting state of skeletal muscle equation
A+M+ADP*Pi; myosin is not bound to actin but cross bridge is energized due to ATP being hydrolized
Calcium levels increase within the cytosol of a skeletal muscle equation
AMADP*Pi; everything is bound together and calcium will bind to troponin so that the binding sites are exposed on actin allowing for cross bridges to bind
Movement of the cross bridge in skeletal muscle equation
A*M; ADP and Pi are lost allowing cross bridge to move it towards the H zone
Rigor mortis
myosin cross bridge remains bound to actin and the muscles are kept in tension for about a day until there’s decomposition of the proteins, ATP generation will stop due to loss of blood circulation but the fluid and electrolites floating around will cause changes to membrane potential
ATP binds to Myosin skeletal muscle equation
A+M+ATP; ATP is not hydrolized therefore cross bridge is not energized and will detach from actin
Creatine phosphate
in the first few seconds of intense muscle contraction muscles will use ATP for around 30 seconds
Creatine kinase
takes a phosphate to createine phosphate and add it to ADP to create ATP
Source of energy
after about 25 minutes carbohydrates from the blood or glycogen stop being used as the primary energy source, then fatty acids will be used, this time will shift depending on how many carbohydrates you intake
Beta oxidation
fatty acids converted into acetyl choline and enter the critic acid cycle
Glycogen in a muscle
will last around 15-20 minutes
How early should a person eat a lot of carbs before intense and prolonged exercise
48hrs to increase glycogen capacity within teh skeletal muscle
Muscular dystrophy
creatine kinase levels are high in the plasma which is an indicator of the muscle integrity
GFR
gulmeral filtration rate is an indicator of kidney function, there’s an inverse relationship between creatinine in tne plasma and GFR
Creatinine
waste product of creatine phosphate after acted on by creatine kinase
Isomeric exercise
muscles remain the same length, if you’re asked to do isomeric exercise multiple times with a rest period you wont be able to hold it for as long after each successive trial
ATP in fatigued muscles
are at the nearly the same levels as ATP within a rested muscle
Conduction failure
if a muscle is constantly contracting it’s always producing an action potential and the levels of potassium outsid ethe cell will be high leading to the cell not being able to repolarize properly, leading to voltage gated calcium channels being harder to open and therefore difficult to produce an action potential
Lactic acid buildup
oxidative phosphorylation can occur even if oxygen levels are low but the amount of ATP will be lower, if pyruvate is unable to cross into the mitochondria due to the lack of oxygen the cell will undergo lactic acid fermentation which will regenerate NMDA! such that ATP can be generation but not a lot
Lactic acid buildup and proteins
the build up of acid doesn’t induce enough of a change of pH to change the conformation of muscle cells
Soreness after exercise
is felt due to inflammation, change in pH, and microscopic tears of the muscle
Inhibition of cross bridge cycling
the cross bridge is moving due to ADP and an inorganic phosphate molecules leaving and as these molecules build up they get in the way of the cross bridges
Central command fatigue
probably what mainly causes muscle fatigue, if you don’t feel like moving the muscle won’t move
Precentral gyrus
area in the frontal cortex which contains the primary motor cortex this is where voluntary muscle movements start
Cortical areas areas
feed the primary motor cortex and tell the muscles when to function
Cingulate gyrus
above the corpus collosum as a bump of tissue, the gyrus is involved in motivation to do anything
Muscle cramping
is mainly involved with sodium and water balance, the increase amount of sodium within the fluid leads to more sodium flowing in when channels open the membrane potential is closer to threshold and easier for muscle cells to create an action potential and contract
Isotonic fluid depletion
equal amount of water and solute loss
Hypertonic fluid depletion
higher loss of water than solute
