Test 3 Review Powerpoint Flashcards
1
Q
Isotonic contraction
A
agonist contracts, antagonist releases basis of movement
pulling up, like with a weight weight
2
Q
isometric contraction
A
agonist/antagonist contract across joint, stabilizing joint
no movement
3
Q
structure of skeletal muscle
A
axons from CNS innervate muscle fibers
actin in sarcomeres
4
Q
alpha motor neuron
A
innervates extrafusal muscle fibers
contraction
5
Q
motor unit
A
alpha motor neuron and all muscle fibers it innervates
6
Q
innervation ration
A
number of muscle fibers innervated by a motor unit
higher is less fine control
lower is more fine control (1:1)
7
Q
Lower motor neurons (LMN)
A
-Ventral horn
-Motor neurons that innervate SKELETAL muscle
directly command muscle contraction
-Ventral horn size differs along length of spine, # of motor neurons differ by how many muscles innervated (arms vs stomach)
-
8
Q
CNS Control of Contraction
A
Increasing firing rate of alpha
motor neurons
Recruiting more alpha motor neurons from motor neuron pool
9
Q
Fast motor units
A
rapidly fatiguing white fibers
low mitochondrial content
10
Q
slow motor units
A
slowly fatiguing
red muscle
high mitochondrial content
11
Q
Excitation of Muscle
A
-Alpha motor neuron fires AP
-Ach released from alpha motor neuron at NMJ
-Nicotinic channels open
-Na+ rushes through sarcolemma, causing type of EPSP called EPP (end plate potential)
-one EPP depolarizes sarcolemma enough to cause AP
-AP sweeps down sarcolemma through T tubules
-Voltage gated Ca2+ channels in T tubules open
-Ca 2+ spills out of sarcoplasmic reticulum
Releases calcium all over, amplified, bigger response
12
Q
Contraction of muscle
A
- Ca2+ binds troponin
- Myosin-binding sites on actin exposed
- Myosin head binds to actin
- Myosin heads rotate
- Myosin heads use ATP to disengage
- Cycle continues as long as Ca2+ and ATP are present
13
Q
Sarcomere
A
basic contracting unit of muscle
14
Q
Relaxation of muscle
A
-As EPP (end plate potential)s end, sarcolemma and T tubules return to resting membrane potential
-Ca2+ returns to sarcoplasmic reticulum via ATP-driven pumps
-Myosin-binding sites on actin are covered by troponin
Fast process because we can contract fast
15
Q
Reflexive movement
A
- controlled by spinal cord and brainstem circuitry
- cannot improve with practice
- initiated by sensory stimulation
16
Q
Voluntary movement
A
- controlled by cerebral corex
- can be improved with practice
- initiated by thoughts
17
Q
Gamma motor neuron
A
- innervate intrafusal muscle fibers
- adjust tension in muscle spindle
- extrafusal muscle fibers to shorten
- if spinals are slack, can’t report length of muscle so GMN contracts poles of spindle to align and gage stretch
- contraction of two poles pulls on equatorial region, keeping 1a axons active
18
Q
Myotatic reflex
A
- stretch reflex
- muscle spindle stretched –> mechanosensitive ion channels, depolarize, 1a afferent activated –> increased AP –> alpha motor neuron activated –> muscle contracts
- monosynaptic arch: one synapse separates primary input from motor output
- muscle length info
19
Q
golgi tendon organ
A
- sensor in skeletal muscle, monitors muscle tension/force of contraction
- 1b axons
- muscle tension info
20
Q
reverse myotatic reflex
A
- muscle tension increases
- 1b axons synapse on interneurons in ventral horn
- interneurons are inhibitory, protects muscle from being overloaded
- for example, if muscle tension increaes and almost snaps, inhibits motor neurons so that muscle neurons stop contracting
21
Q
1a
A
muscle length info
22
Q
1b
A
muscle tension info
23
Q
corticospinal tract
A
- LATERAL PATHWAY (voluntary movement)
- voluntary movement in humans
- if cut, lose muscle control, rubrospinal can take over and help rebuild general control but lose fine muscle
24
Q
rubrospinal tract
A
LATERAL PATHWAY (voluntary movement) important in non primates
25
tectospinal tract
VENTROMEDIAL (involun movement of proximal and axial muscles)
-orienting response, esp with eyes
26
vestibulospinal tract
VENTROMEDIAL (invol move of proximal and axial muscles)
| -stability of head and back area to keep head
27
Pontine reticulospinal tract
VENTROMEDIAL (invol movement of prox and axial muscles)
enhances antigravity reflexes
balance
28
Medullary reticulospinal
VENTROMEDIAL (invol movement of prox and axial muscles)
liberates antigravity muscles
balance
29
motor area 6: what projects heavily into it?
basal ganglia and cerebellum
30
motor area 6: where does it project heavily?
area 4
31
roland's tapping experiment
motor areas of brain
- M1=simple movement
- SMA + M1 complex movement
- SMA thinking about complex movement
32
premotor area
planning movement
33
function of motor cortex
M1 neurons code for force and direction of movement
34
Force
frequency of action potentials
35
direction
population coding of action potentials
36
Basal ganglia
willed movement
37
parts of basal ganglia
```
caudate nucleus
putamen
globus pallidus
subthalamic nucleus
substantia nigra
```
38
caudate nucleus
```
motor processes
learning processes (associative, etc)
executive functioning
```
39
globus pallidus
movement
| pacemaker
40
putamen
regulate movements
| learning
41
subthalamic nucleus
action selection
42
substantia nigra
rewards, eye movement, motor planning, addiction
43
Parkinson's disease
- degradation of neurons in substantia nigra
- depleletion of dopamine, prevents normal motor activity to basal ganglia
- bradykinesia: slowness in movement
- difficulty initiating willed movements
- increased muscle tone and rigidness
- tremors of hand and jaw
44
process behind parkinson's (chem)
- depletion of dopamine
- closes funnel that goes through Ventral Lateral Nucleus to SMA (cortex)
- DA inhibits neurons that send inhibitory output
- over excitation in subthalamic nucleus, can't fire
45
treatments of parkinson's
- L-DOPA treatment: activates neuron in putamen, replaces lost DA in striatum
- DBS: stimulates subthalamic nucleus, less excitatory on global pallidus, less inhibition on VL, more excitatory on SMA
46
Huntington's disease
- loss of neurons in caudate, putamen, and globus pallidas
- hereditary, progressive, fatal
- hyperkinesia and dskenesia: abnormal movements
- dementia; cognitive, personality
- autosomal dominant
* *chorea: spontaneous, uncontrollable, purposeless movements
- losing inhibitory input, opening funnel to SMA
47
Cerebellum
- sequence/timing of muscle contractions
- planned, voluntary movement
- multi joint movement
- M1 through VL
48
Cerebellar disease
DIDAD
- dysmetria: loss of coordination
- Dysdiadochokinesia: inmpaired ability for rapid alternative movements
- Ataxia: loss of full control of body movements
- Intention tremor
49
hyperreflexia
motor cortex lesions
| increased reflexes
50
hypertonia
motor cortex lesions
| increased muscle tone
51
babinsky reflex
motor cortex lesion (if exists after 12 months
| upward flexion of big toe
52
clonus
motor cortex lesion
| rhythmic cycles of contraction and relation after stretch of limb muscle
53
point to point communication
most neurons
| Glu, GABA, peptide NTs
54
secretory hypothalamus communication
going to various neurons
ANS: sympathetic, parasympathetic
through blood system
55
diffuse modulary communication
diffuse like secretory
going to various neurons
but doesnt go through blood system
56
lateral and medial hypothalamus
functions to control homeostasis
57
periventricular hypothalamus
- functions in circadian rhythms and endocrine system
- superchiasmatic nucleus
- circadian rhythm
- endocrine system
- pituitary
- more innervated with blod vessels: secretory hypothalamus communication
58
hypothalamic magnocellular cells
- posterior pituitary
- true neural tissue
- oxytocin, vasoprecin (love hormone for prairie voles, in humans, kidneys for water concentration
59
hypothalmic parvocellular cells
- anterior pituitary
- true gland
- endocrine system
- hormones for puberty: growth, follical stimulating, glutenizing, prolactin (testes, gonads)
- certain mass (obese people=earlier) --> glutenizing --> testosterone and estrogen
60
sympathetic nervous system
fight or flight
| increases heartrate, blood pressure, eyes dilate, rapid breathing
61
parasympathetic nervous system
calm
rest and digest
digestion, lowers heartrate, lowers blood pressure, return to normal breathing
62
outputs of CNS from somatic motor fibers
to skeletal muscle
63
outputs of CNS from ANS (sympathetic and parasymp systems)
to smooth muscle, cardiac muscle, gland cells
64
sequence of events ins tress response
Amygdala feels stress, increases reaction, signals to hypothalamus
Release corticaltropin
Goes to anterior pituitary (highly innervated with blood vessels)
ACTH has to be released into blood to get to adrenal glands
Cortisal
65
increased cardiovascular tone in chronic stress
hypertension, atherosclerosis
66
mobilization of energy in chronic stress
fatigue, diabetes, obesity
67
suppression of digestion in chronic stress
ulcers
68
suppression of growth in chronic stress
decrease growth + muscle mass, dwarfism
69
suppression of reproduction in chronic stress
decreased libido, no ovulation
70
suppression of immune system in chronic stress
infections
71
sharpening of cognition in chronic stress
memory impairment
72
stimulants
- cocaine, amphetamines, etc block NE and DA receptors
- if you take too quickly, NE causes increased heartrate and die
- addiction
73
ADHD
- DAT transporter works in reverse, increases DA in cleft
- symptoms: inattention, hyperactivity, impulsivity
- knockdown DAT transporters in mice --> hyperactive
- knockout DAT transporters in mice --> extremely hyperactive
74
Ecstasy (MDMA)
- higher affinity for SERT than 5HT itself
- reverses SERT activity
- long term=loss of serotonin axons
- depression, anxiety, disturbed sleep, substance abuse disorders, mood
75
sexual differentiation
```
mullarian ducts (f) preset for humankind
TDF
mullarian ducts dev into oviducts
wolffian ducts into vas deferens
```
76
male sexual dev
```
XY chromosomes
TDF
testes
AMH means no mullarian ducts, instead wollfian (seminal vesicles, prostate glands, etc)
male brain, and male external genitalia
```
77
female sexual dev
no tdf, ovaries, no AMH, mullarian ducts (inner vagina, uterus, fallopian tubes), outer genitalia, female brain
78
gonadal intersexuality
- "true hermaphroditism"
- gonads have both ovarian and testicular tissue
- majority are infertile
- external genitalia variable
- female structure usually predominate
- most identify as women
79
turner's syndrome
- XO female
- neck webbing
- short, barrel chest
- no ovaries
- no gonadal hormones
- infertile
- no testosterone
- problems with visual/spatial/mathematical tasks
80
kleinfelter's syndrome
- XXY male
- intersexuality
- "pseudo hermaphroditism"
- tall, small testes, gynecomastia
- feminine body contours
- low testosterone leves
- language skills impaired
81
Complete AIS (androgen insensitivity syndrome)
- XY male
- intersexuality
- "pseudo hermaphroditism"
- normal prenatal testosterone levels
- mutation in androgen receptor
- shallow vagina, undescended testes
- no male or female internal genitalia
- taller than most females
- caused by absent or non functional androgen receptors
82
Partial AIS
XY Male
Mutation in androgen receptor
Semenya olympics
83
Congenital Adrenal Hyperplasia (CAH)
- XX Female
- intersexuality
- "pseudo hermaphroditism"
- defect in production of enzyme cortisol
- hyperplasia of adrenal cortex
- increased cortisol precursor steroids that get converted to androgens
- masculinize female genitalia
- behaviorally masculinized, likely to be sexually attracted to women
- if untreated, infertility
84
Second wave of hormones
- puberty
- hypothalamus: GnRH (gonadotrpin-releasing hormone)
- activates anterior pituitary (LH and FSH)
- Females: ovaries, estrogen, breasts
- Males: testes, teststerone, male genitalia
85
Estrodiol
estrogen
monthly on period
increase in synthetic spines in hippocampus
to choose mate, increased cognition
86
right hemisphere 2% larger
straight men
| lesbians
87
hemispheres are nearly same size
straight women
| gay men
88
sexually dimorphic nucleus (SDN)
inah 3 INH 3 in humans
sexual orientation
women have more widespread of cells, diffuse
89
Dimorphisms
1. ) differences in density, size of cells, # of axons and synapses (amygdala, symmetry of hemispheres, cerebral cortex etc)
2. ) microscopic/molecular differences (size and number of nerve cells, synapses, brain circuits, hormone receptors, neurotransmitters)
90
Male cognition
- navigate with compass direction
- mental rotation
- judgment of line orientation
- more aggressive, competitive
91
female cognition
- navigate with landmarks
- verbal fluency
- reading facial expression
- memory of object location
92
same sex attraction
- early play patterns predict sexuality
- women exposed to high androgens more likely to be gay
- prenatal hormones, so conversion therapy doesn't work
93
otoacoustic emissions
- men roughly equal
- straight women have most
- bi and gay women less than straight
94
Glascow coma scale
content: cerebral cortex
VS
arousal (RAS): brainstem modulatory systems
95
EEG
measures voltages generated by excitation of many neurons in cerebral cortex
depends on
1. number of neurons
2. synchronous activity
96
Synchronous activity of neurons
pacemaker (thalamus)
high freq
high amplitude
sleep
97
seizure activity
runaway excitation of brain circuitry
-> pathologically synchronous activity (high freq high amp)
very synchronous
-upset in balance of synaptic excitation and inhibition
98
treatment for seizures
-GABA agonist
promote inhibition mediated by GABA
-in seizures, sodium channels try to stay open for longer, more sodium enter, hyperexcitable
--> block Na+ channels
99
Stage 1 of sleep
- transitional sleep (eyes make slow rolling movements, drowsy)
- lightest
- only few minutes
100
Stage 2 of sleep
- EEG is irregular, short bursts
- sleep spindles diminish brain's sensitivity to sensory stimuli (thalamic pacemaker)
- k complex keeps person asleep
101
stage 3 of sleep
- 20-25% delta waves
- delta wave
- high amplitude, low freq
102
stage 4 of sleep
- increase in delta waves
- deepst stage of sleep
- changes most during life
- decreases with age, ending after 60 years
103
REM sleep
- sympathetic system
- no muscle tone, paralyzed body
- beta rhythms
- brain incredibly active (dreaming is random activation of circuits that are easily accessible)
- newborn has mostly REM, decreases with age
- paradoxical sleep (waking EEG, but not easily aroused)
104
Bottlenose dolphin
- microsleeps
| - sleeping with one brain hemisphere
105
Neurotrans in response to sleep (increase or decrease in firing rate?)
Increase: NE, 5-HT, Ach
decrease: dopamine
106
sleep in brain processing, memory, creativity
- novel solutions to complex problems
- 3x creativity
- synaptic connections are linked and strengthened
107
Hypocretin
dog falling asleep
arousal
mutation in receptor, narcolepsy, blocked
