exam 4 Flashcards
muscular responses
twitch
summation
incomplete and complete tetanus
recruitment of motor units
length tension relationship
twitch
muscle completely relaxed before next stimulation
not very helpful- need sustained contraction or several small contractions
motor neuron action potential
muscle fiber action potential
latent period
delayed muscle contraction
due to contraction process (last exam) (takes time)
muscle contraction. relaxation
1 muscle contraction (impulse) followed by relaxation
summation
muscle couldn’t fully relax before next stimulus
additive
some relaxation
incomplete and complete tetanus
stimulations closer and closer together
soon relaxation not possible
sustained contraction
incomplete tetanus
still some relaxation
complete tetanus
no opportunity for relaxation
recruitment of motor units
motor unit- nerve and all muscle fibers it controls
length tension relationship
optimal range pre contraction overlap actin and myosin
myosin heads have something to grab onto-have job- sliding- causes momentum and force
little bit of bend helps- like lifting weights
outside optimal range = significant loss in maximum tension
too short- no sliding- no momentum
too long- myosin heads have nothing to grab onto
how does length tension relationship affect heart health
hearts have sarcomeres
congestive heart failure: weak contractions- overly stretched
more volume brought in over stretches and contracts w/ less strength
can’t release volume let in
Muscle energetics
Stored ATP
Creatine Phosphate
Intensity and duration of activity
anaerobic and aerobic pathways
lactic acid threshold and oxygen debt
fatigue
recovery
Muscle energetics stored ATP
first 5 seconds used
body cant store much ATP
usually used right away
creatine phosphate
CP
AT rest can be combined with ADP
breaks down and manufactures ATP in 1 step (1 ATP)
can be reversible
ATP + C ←→ ADP + CP
a cell can only contain so much CP
intensity and duration of activity
short duration, high intensity
long duration, low intensity
anaerobic pathways
without oxygen- doesnt participate in reactions
there but not participating
cells cant store glucose but can store glycogen- has to be broken into glucose
cytosol- fluid portion of cell- glycolysis occurs
net gain of 2 ATP
produce pyruvic acid using glycolysis (a series of reactions) in cytosol
if oxygen is still not being utilized, pyruvic acid is converted into lactic acid
uses carbohydrates as energy source
aerobic pathways
pyruvic acid and forward uses oxygen
if oxygen is available pyruvic acid moves into mitochondria
if oxygen is not available pyruvic acid is converted into lactic acid
fatty acids and amino acids can be used as an energy source, only in the presence of oxygen
can still use carbohydrates
makes around low 30 something ATP
fatty acids would produce more ATP per molecule
amino acids- want to use to make proteins, not use as energy
fatigue
short duration exercise = depletion of ATP and CP stores plus lactic acid production- high intensity
run out of CP- has to rest to make more
anaerobic- lactic acid build up- interferes with enzymes (pH changes makes enzymes unhappy)
lactic acid doesn’t stay put- blood circulation carries it away- does NOT make you sore
goes to liver to be converted into glucose- uses ATP- no net gain (wash)
long duration exercise = depletion of glycolysis stores- low intensity
“hitting the wall”- depletion of glycogen
why people have to eat during a marathon (carbohydrates)
to recover- rest and eat
recovery
removal of lactic acid
lactic acid doesn’t stay put- blood circulation carries it away- does NOT make you sore- short duration
goes to liver to be converted into glucose- uses ATP- no net gain (wash)- short duration
to recover- rest and eat- long duration
delayed onset muscle soreness
confined to eccentric muscles
very small tears in muscles, connective tissue, and/or tendons
micro tears
controlled muscle contractions and lengthening, myosin head being torn from actin
types of contraction
isotonic
isometric
isotonic contraction
same tension or force
length changes
concentric
muscle shortens
eccentric
muscle lengthens
myosin heads are breaking off actin
micro tears- greater gains and strength than concnetric
larger thicker stronger structure- maybe more myobrils in that area
doing eccentric movements with controlled slow lowering will maintain strength with less time and less reps
isometric contraction
same measure
no movement at joint
muscle maintains same length but will develop tension
muscle fiber types
different kinds of cells (fibers)- like red and white meat
slow twitch (red; type I)
fast twitch glycolytic (white; type IIb)
fast twitch intermediate (white; type IIa)
slow twitch (red; type I) muscle fiber
ATPase enzyme version that energizes myosin slowly= contract slowly
more abundant blood supply
manufactures myoglobin- has a lot- related to myoglobin
best endurance
fast twitch glycolytic (white; type IIb) muscle fiber
no/ few myoglobin
get majority of ATP through glycolysis
less mitochondria
worst endurance, most powerful
fast twitch intermediate (white; type IIa) muscle fiber
have a fair amount of myoglobin
in the middle
have mitochondria
decent blood supply
slow vs fast twitch
how fast contract
depend on ATPase enzyme
red vs white
blood supply
more= red
blood delivers oxygen to make ATP (aerobic respiration)
white= less blood supply
myoglobin
smaller
oxygen bind to (give red color)
hemoglobin
larger
giver red color
rhabdomyolysis
skeletal muscles rupture and contents spill out in blood stream
one of the contents (myoglobin)
kidneys- filter through size
myoglobin can start filtering but cant finish- plug up filtration
go into kidney failure
lever systems
defined by order of components (look at middle)
fulcrum- joint
flat part- bone
force- muscle attaches to bone
first class (resistance-fulcrum-force)
second class (fulcrum-resistance-force)
third class (resistant-force-fulcrum)
first class (resistance-fulcrum-force)
scissors
fulcrum in middle
triceps brachii
second class (fulcrum-resistance-force)
wheelbarrow
resistance in middle
standing on tip toes
third class (resistant-force-fulcrum)
force in center
tweezers
biceps brachii
Smooth Muscle
anatomy
actin and myosin
excitation-contraction coupling
relaxation
smooth muscle anatomy
no striations, single nucleus, spindle shaped
smaller
single nuclei
narrow on ends widens at middle (spindle)
connected by gap junctions-electrical synapse
rudimentary sarcoplasmic reticulum
calcium coming from outside cell (5x more outside)
no calcium storage
no t-tubules
no impulse deep in cell
most are single unit (visceral)
n epimysium, perimysium, fascicles, or endomysium
smooth muscle has gap junction
cant have flow and cell to cell communication if covered by endomysium
no sarcomeres
no pattern to actin and myosin overlap
no striations
smooth muscle actin and myosin
Greater ratio of myosin to actin than in skeletal muscle
And more crossbridge units per actin than skeletal muscle
more myosin attached to actin
doesn’t have to be from same cell
smooth muscle excitation-contraction coupling
calcium (from intracellular and extracellular sources) enters sarcoplasm
no troponin or troposyosin
binding spots are always open
calcium binds to calmodulin
regulator protein
binding to calmodulin activates enxyme kinase
presence of calcium activates (phosphorylates) myosin light chain kinase (MLCK)
Activated MLCK causes cross-bridge formation
activates and energizes myosin
contraction not dependent on calcium but on myosin phosphorylation
control when myosin is activated, doesn’t control binding sites
calcium is still the trigger- just trigger different things
skeletal: myosin energized all time, binding sites controlled
smooth: binding sites always available, control activation of myosin
smooth muscle relaxation
calcium removed
inactivation (dephosphorylation) of MLCK
comparing smooth and skeletal muscles
more cross-bridges per actin in smooth muscle
smooth muscle regulation at level of myosin, not troponin and actin
tone held longer in smooth muscles with less energy requirement
smooth muscle contraction often phasic or rhythmic (ex) peristalsis)
smooth muscles can be stretched more without loss of tension (plasticity)
smooth muscle contractions slower
not all smooth muscles require neural stimulation
ore cross-bridges per actin in smooth muscle
smooth muscle: more myosin
tone held longer in smooth muscles with less energy requirement
consumes less energy- lose less ATP as heat
contract for longer
more efficient
smooth muscle contraction often phasic or rhythmic (ex) peristalsis)
patterns of contraction (peristalsis)- stimulates neighboring cells
cell to cell electrical synapses
small intestine- 18-20 ft long- move contents along in segments, 1 segment contracts and push contents forward to next segment and starts over- like tube of toothpaste
ex) intestines, urine from kidneys to bladder
visceral smooth muscle carries out peristalsis
multi unit smooth muscle- works like skeletal muscle motor unit
iris of eye: pigmented smooth muscle- 2 sets, stimulated by nerve- make pupil dilate and contract
smooth muscles can be stretched more without loss of tension (plasticity)
more myosin from other smooth muscle can attach
different myosin filament
smooth muscle contractions slower
held longer
when relaxed: spindle shaped
when contracted- more globular (fatter) and shorter
actin and myosin closer to surface
not all smooth muscles require neural stimulation
hormones- many respond
uterus
stretch
reflex
stomach overfills and stretches stomach
reflexively
right hand side of graph: move intersecting point to the right- 2x as far away
can stretch a tremendous amount before losing tone and strength
more myosin
Why does glucose uptake by a skeletal muscle cell require transporter such as GLUT4? In other words, why isn’t simple diffusion possible
Glucose is large and polar
What stimulates the insertion of GLUT4 into the sarcolemma?
insulin dependent; exercise dependent (Skeletal muscle contraction)
The existence of GLUT4 in the sarcolemma does not guarantee glucose uptake into the cell. Why? what else is required?
concentration gradient
Exercise helps reduce blood glucose levels in people, even if their insulin resistant unless their cells can no longer respond to insulin efficiently. how is this possible
exercise specific
exercise at a submaximal level flow chart
glucose released from liver
blood glucose levels decrease
insertion of GLUTs into sarcolemma
diffusion of glucose into cells
Skeletal muscles also use glycogen but they use it right away so it doesn’t get released into the bloodstream
LDH
Converts pyruvate into lactate
reversible
H+
Minimizes changes of ph
lactate
produced all the time
lactic acid
Produced during anaerobic respiration
in an actively contracting skeletal muscle cell what would cause a decrease in the rate of glucose diffusion into this cell
if GLUT4 is saturated; # of transporters- Can only transport one glucose at a time- if GLUT4 is saturated wont work
change in concentration gradient
In order to produce lactate from pyruvate what items or inputs are required
LDH, H+, NADH
During glycolysis 1 molecule of glucose which has six carbons is split into two molecules of pyruvate which has three carbons each. Each pyruvate molecule can then be converted into a molecule of lactate which also has three carbons. Oxygen is not required for any of these processes to occur why
no carbon dioxide is produced
no change (decrease) in total number of carbons
After a lactate is produced in the sarcoplasm where might it go and how might it be used
into mitochondria; exits cell
mitochondria Can convert lactate into pyruvate
when exiting the cell it is cotransported with H+ ions- the H+ ions become the issue
How does the production of lactate protect or buffer the cell from acidosis which is defined as the accumulation of H + in a fluid filled compartment
picks up 2H+
Look at the structure of lactate. Do you think it can leave the cells via simple diffusion? Why or why not
polar; relatively large
the 3 fates of lactate
exit cell via MCT
mitochondria
converted to pyruvate
If lactate is an energy source for the cell in which it is produced, why does it spill into the blood in other words why to blood lactate levels increase during exercise especially in untrained people
production>utilization
Lactate is not the problem H+ Co transported is
LDH is an enzyme and thus a protein. in order for a skeletal muscle cell to increase the amount of LDH within the sarcoplasm, what cellular processes must be completed? what organelles need to be added to figure in order for LDH to be produced?
increased protein synthesis= more copies of enzyme LDH
Through dedicated training, the speeder level of effort coinciding with a persons lactate threshold improves. Within the skeletal muscle cell what changes might have occurred to permit this improved lactate threshold resulting in less lactate spilling owl into the blood
more LDH enzyme (synthesis)
more mitochondria
Changes in the extracellular fluid and blood flow chart
Items diffusing from the muscle cell are lactate and H+
lactate is used by other organs like the heart
H+ cotransports and causes problems
Transporter used during diffusion is MCT
Location of transporter in the muscle cell is in the sarcolemma
Impact on ECF and blood pH: decrease- H+ added (lactic acid)
Lactate
produced from pyruvate
H+ proton
produced from ATP hydrolysis
Suppose you are measuring changes in blood composition in real time in an untrained person like Shelby who is jogging a moderate pace on a treadmill and you noticed that as lactate levels increase in her blood so do H+ levels why is this is lactate the original source of these additional H+ ions
Lactate co transports with H+
Hypothesize how Shelby’s lactate threshold rest would change with dedicated aerobic training. What changes would occur within skeletal muscle cells to delay the spilling of lactate into the blood
more LDH (enzyme) and more mitochondria= raise lactate threshold
lactic acid
produced during anaerobic respiration
proton donor- produces protons
decreases pH in sarcoplasm
lactate
produced during aerobic respiration
proton acceptor (remove protons from fluid
keep pH in sarcoplasm neutral (buffer)
Skim back through this case study and identify the causes of H+ production and accumulation in the sarcoplasm, extracellular fluid, and blood. Is lactate ever the original source of these ions were just guilty by association? Then go back to the very first page of this case study and re examine your thoughts from activity one can you generate a more detailed list of misconceptions now
H+ originate from ATP hydrolysis and NADH
lactate is not the cause- guilty by association
What is the relationship between the production of lactate and the burning sensation many people like Shelby described after they begin a new exercise regimen or activity how is the brain made aware of this situation
H+ stimulate pain receptors
Hypothesize what changes could occur within skeletal muscle cells that would help prevent the burning sensation after completing an aerobic exercise activity like jogging
increased LDH (enzyme) and increased mitochondria
nervous system basics
divisions
classifications of neurons
neuroglial cells
axon regeneration
impulse processing
divisions of nervous system
central nervous system
peripheral nervous system
sensory division
motor division
sensory division of pns
sensory receptors
sensory nerves
sensory receptors
all over skin
pick up touch, ect
carried by sensory nerves
sensory nerves
can only carry toward CNS
cant go back to nerve
motor division of PNS
somatic
skeletal muscle
conscious control
autonomic
smooth and cardiac muscle
glands
no conscious control
classifications of neurons
anatomical
unipolar
bipolar
multipolar
physiological
sensory
interneurons
motor
unipolar neurons
1 process that exists
splits
1 region that acts as dendrite- labelled at very end because the rest is myelinated
1 region acts as axon
sensory division- most common in sensory
bipolar neurons
1 dendrite
1 axon
sensory division
multipolar neuron
at least 2 dendrites
1 axon
motor and interneurons
interneurons
transferring from 1 sensory neuron to motor neuron
connecting neuron
only CNS
motor
away from CNS and toward effectors
neuroglial cells
CNS- support neuron- don’t send impulse
astrocytes
ependyma
microglia
oligodendrocytes
PNS
Schwann cells
astrocytes
“star”
have extensions
sit on top of capillary
deliver nutrients to neuron from capillary
deliver waste to capillary from neuron
provide protection: apart of the brain barrier
level of selectivity of what gets to neuron
picky about size and polarity
loves nonpolar
hates polar
ependyma
fluid filled cavity
fluid: cerebral spinal fluid
create cavity that holds fluid
creates barrier to prevent getting to neuron
selective about polar substances
microglia
carry out phagocytosis
clean up debris, cell fragments, infectious agents
oligodendrocytes
insulates
allows impulse to go faster
Schwann cells
myelinate ad increase speed
help regenerate damaged axon
axon regeneration
cell body in tact
axon distal to injury dies
schwann cells stay
own cell and entity
axon can follow pathway and grow in tube
cant grow anywhere on muscle fiber- has to connect with motor end plate
axons don’t grow very fast
1mm a day
impulse processing
facilitation
convergence
divergence
facilitation
raise something toward threshold without reaching threshold
“assist or help”
convergence
“come together”
multiple presynaptic neurons
terminate on same postsynaptic cell
raise toward threshold
divergence
motor unit is an example
1 presynaptic cell, multiple postsynaptic cell
CNS- Bones of cranium and spinal vertebrae
hard and good protection
no give if there is inflammation
swelling goes into CNS structures instead
CNS meninges
layers
partitions
subarachnoid space
epidural space
Layers of CNS meninges
form a layer around brain- fold in and make partitions
dura mater
outermost layer
durable
toughest
lots of collagen
arachnoid mater
look sweb like
CSF
between arachnoid mater and pia mater
pia mater
on surface of CNS
follows nooks and crannies
arachnoid granulations
where cerebral spinal fluid exits into venus blood
partitions of CNS meninges
make control of cross communication
separate left and right halves of brain
surface of brain unmyelinated vs. center of spinal cord unmyelinated
fissure: deep crevice
Falx cerebri
separate left and right halves of cerebrum
longitudinal fissure
Falx cerebelli
separate left and right halves of cerebellum
Tentorium cerebelli
separate cerebellum from cerebrum
transverse fissure
subarachnoid space
csf circulates
provide nutrition and cushioning
epidural space
between dura mater and spinal cord
ventricles and cerebrospinal fluid
functions of CSF
composition of CSF
production by choroid plexuses in ventricles
ventricles: all CSF circulates here
choroid plexus makes CSF
ependymal cells
circulation
functions of CSF
provide nutrition and cushioning
composition of CSF
proteins are different
size: proteins filtered out from plasma to CSF
osmolarity the same
no net gains or losses by osmosis
good bc no room for gains of csf
production by choroid plexuses in ventricles
ventricles: all CSF circulates here
choroid plexus makes CSF
circulation
constant exit through arachnoid granulations
what draws CSF in forward direction
blood brain barrier
astrocytes
contains pericytes
pericytes (a type of smooth muscle cell of the microcirculation)
capillary endothelium with tight junctions
simple squamous epithelium
to leave: have to leave plasma, then get across capillary, then through pericyte and out of astrocyte
how blood CSF different: not nearly as restrictive, no go between
blood CSF barrier
choroid epithelial cells
basal membrane
endothelium of pia mater capillaries
comparison of BBB and BCSF
BBB
selective at endothelium
tight juctions there
have to have carriers and be fat soluble
move from blood out
BCSF
not held by tight junctions
proteins wont filter
selective at choroid plexus ependymal cells
can go both directions
still need a carrier protein and be fat soluble
cerebrum
gyri, sulci, and fissures
lobes
hemispheric dominance (lateralization) and corpus collosum
memory
gyri
rased area of the cerebrum
also called convolutions
sulci
depression of cerebrum
fissure
a fissure is different than a sulci because fissure are more prominent and deeper.
lobes of cerebrum
frontal lobe
parietal lobe
temporal lobe
occipital lobe
frontal lobe of cerebrum
primary motor cortex
red/ pink in picture
all skeletal muscles
controls muscles on opposite side of body
in front of central sulcus
broca’s area
just for speech
frontal eye field
coordination
level of control
move eyes up and down together
can also move 1 eye laterally and the other medially as if looking at finger
cortex
near surface
association area
higher processing
concentration
math
plan for future
actions have consequences
take a long time to mature
cerebral cortex
grey matter
on surface
unmyelinated
more cross talk
smooth brain syndrome
a condition characterized by a lack of gyri and sulci in the brain, leading to developmental issues and cognitive impairments. (less wrinkles)
parietal lobe of cerebrum
primary somatosensory cortex
yellow strip in picture
sensory area involved with cutaneous senses
skins senses
touch taste temperature pain
some internal organs that are near surface
somatosensory association cortex
word choice
understanding words and speech
pauses emphasis tone
gustatory cortex
eating and taste
taste food
temporal lobe of cerebrum
primary auditory cortex
hearing
raw sounds
the more specialized areas
what sounds mean
recognizing patterns
Wernicke’s areas
between temporal and parietal lobe (in middle)
put all the senses together
how to watch movie
occipital lobe of cerebrum
primary visual cortex
vision
seeing objects
visual association area
recognize individuals
see background
way hold themselves- when cant see face
hemispheric dominance (lateralization) and corpus collosum
hemispheric dominance (lateralization)
generally, people concentrate on information
most people are left-brain dominant- 90% of the population
left hemisphere: language, analytical
right hemisphere: orientation of motor tasks, recognition of patterns, emotional thought processes, personality
corpus callosum
allow left and right cerebrum to communicate with each other
very controlled
motor cortex
mostly made to control facial muscles and hands
better 50%
skeletal muscle
facial expression
chewing
speaking
eatng
sensory cortex
primarily controls skin and nerves for speech and hands
speech
chewing
swallowing
big areas of feedback
Phineas gage
right hemisphere dominant
was not affected
could still talk, problem solve, communicate, could do everything
left hemisphere non dominant
affected
change personality
