muscles and the brain Flashcards
3 regions of the brain
midbrain, forbrain, hindbrain
case study that found out where emotions are localized in the brain
Phineas Gage
hindbrain
cerebellum, medulla, pons; basic fundamentals for survival/ living
midbrain
relay system; transmits information necessary for vision and hearing
forebrain
thalamus, hypothalamus, pituitary gland, pineal gland, cerebral cortex; movement, sensory processing, emotions
cerabellum
coordinating movement and balance; integrate and redefine sensory and motor info
maddula
respiration, circulation, breathing, blood pressure, etc; autonomic NS
pons
transmit info from medulla/cerebellum to forebrain
thalmus
relay station for sensory info to brain; sends to specific specialized region
hypothalamus and pituitary gland
The hypothalamus produces several releasing and inhibiting hormones that act on the pituitary gland, stimulating the release of pituitary hormones; endocrine system powerhouse
pineal gland
circadian rhythm; regulated production and circulation of melatonin
cerebral cortex
higher-level processing; language, memory, reasoning, thought, learning, decision-making, emotion, intelligence and personality
what does the folded struct in the cerebral cortex do?
increases the brain’s surface area so more neurons -> higher cognitive function
gray matter
soma and dendrites of neurons
white matter
myelinated axons of dendrites
gyrus
ridge of the cerebral cortex
fissure
large furrow that divides the brain into lobed
sulcus
shallower grooves surrounding a gyrus
what cortex is in the frontal lobe
olfactory and gustatory cortices= taste and smell
*responsible for decision making and complex thinking
what cortex is in the parietal lobe
primary somatosensory cortex= detect pain, temp, position and vibration
*body and spatial awareness
what cortex is in the occipital lobe
visual cortex= processes visual info
what cortex is in the temporal lobe
auditory cortex= processes speech and sound
central suclus
separates the primary motor and primary somatosensory cortices; these 2 cortices in constant communication
limbic system function
processing and regulating emotions, memory, and learning
key parts of limbic system
hippocampus and amygdala
hippocampus role
memory center; hold short-term memories and transfer them to long-term storage
amygdala role
emotion center; fight or flight responses
dopamine
happiness/ pleasure neurotrasmitter
serotonin
satiation of happiness neurotransmitter
start of reward pathway
VTA
4 parts of reward pathway
-amygdala: feeling the reward
-hippocampus: having memory of that feeling
-nucleus accumbens: understanding what you did physically to achieve that feeling
PFC: focus on feeling
what happens to reward pathway activation as dopamine increased
increased activation
what happens when reward pathway continuously activated
more serotonin must be released to feel same level of satiation/ reward
ex. drug addiction
physiological causes of depression
- not enough of a neurotransmitter made
- not enough postsynaptic receptors
- too fast presynaptic reuptake
depression is in imbalance of which neurotransmitters?
dopamine, serotonin, norepinephrine
cognition
the ability to take in, interpret and recall knowledge, learning and forming thought
what relays info to cerebral cortex
hippocampus
how is information solidified -> LTM
during sleep
synaptic plasticity
more we use synapse the stronger it becomes
* enlarged dendrites
* more ligand gated ion channels
process of learning
strengthening synapse through positive feedback -> makes easier to recall
long term potentiation
a long-lasting increase in synaptic efficacy following high-frequency stimulation of afferent fibers.
EEG
tracks brain activity by measuring electrical impulses
brain waves when awake
beta waves
brain waves when sleep
delta waves
stages of sleep: N1
drowsy, in between awake and asleep
stages of sleep: N2
onset of sleep; heart rate and body temp drop
stages of sleep: N3
deepest state of sleep and most restorative for bodyl blood pressure, metabolism and breathing drop
stages of sleep: REM
dream state and very restorative for the brain; happens 90 mins after sleep and every 90 mins in cycle
* STM -> LTM
3 steps of learning
1) acquisition; new info comes in
2) consolidation; memories stabilize during sleep
3) recall; access stored info
3 types of muscle (rank fastest/ most power -> slowest)
skeletal, cardiac, smooth
what type of muscle does not have stratiaton
smooth
why can muscles get bigger/smaller
wrapped in connective tissues (flexible lining)
muscle bundle
a section of striated muscle wrapped in connective tissue filled with muscle fibers; a bunch of fused nuclei
myofibril
longitudinal parallel contractile elements of a muscle cell that are composed of myosin and actin.
stratiatons: thin filaments
actin
striations: thick filaments
myosin
how are muscles contracted
tropmyosin binds to actin
sacroemre
the basic contractile unit of muscle fiber; myosin and actin sliding past each other
A band
dark section of sarcomere that does NOT change length during muscle contraction; myosin and actin overlap
I band
light section of sarcomere that shortens during muscle contraction; only actin
how much shorter does the I band get during contraction
30%
what happens to filaments when muscles contract
thin filaments slide in (actin)
cross bridge cycle (4 steps)
1) myosin head binds to ATP -> detach from actin
2) hydrolysis of ATP -> ADP; myosin head cocks back
3) myosin head binds to actin binding site to form cross bridge
4) ADP released to produce power stroke -> thin filament slides
what happens to the sarcomere when the filaments slide
shortens
muscle excitation
motor neurons synapse with muscle cell -> release acetylcholine -> depolarize them (Na+)
t-tubules
sewer drains for Na+ ions -> depolarize sarcoplasmic reticulum -> release Ca++
what does Ca++ do
binds to troponin to moves tropomyosin out of the way so myosin can bind -> stimulated contraction
what happens when there is low Ca++
myosin binding site is blocked and muscle is relaxed
Antagonist Muscles
2 muscle groups working to do opposite things; flexion and elongation
ex. biceps and triceps
agonist muscles
multiple muscle groups work to do the same thing; either flexion or extension
why do smooth muscles contract slower
-not striated so no troponin or tropomyosin -> less contraction force
- less Ca++ pumps -> slower contraction
tetanic contraction
muscle contraction of sustained force
twitch
response from a single action potential fired
muscle action potenial differences from neuron
resting = -90 mV
goes up to only +30 mV
no refractory/ hyperpolarization period
force summation
second action potential fired before muscle has fully relaxed; increasing frequency of stimulation = greater force (summation)
