AP4 Flashcards
1
Q
The Central Nervous System Consists of
A
Brain and spinal cord
2
Q
Divisions of PNS
A
Sensory/ Afferent (somatic)
Motor/ Efferent (autonomic)
3
Q
PNS- Sensory/ Afferent division
A
nerves+ ganglia
sends signals towards the CNS
4
Q
PNS- Motor/ Efferent Division
A
Sends signals away from CNS
5
Q
PNS- Motor/ Efferent (Somatic Nervous System)
A
Voluntary control of skeletal muscle
6
Q
PNS- Motor/ Efferent (Autonomic nervous system) controls….
A
Involuntary control of cardiac muscle, smooth muscle, and glands
Sympathetic (fight/ flight) and parasympathetic (rest/ digest) divisions
7
Q
Sympathetic ANS division
A
fight/ flight
8
Q
Parasympathetic ANS division
A
rest/ digest
9
Q
Neuroglia/ glia cells
A
support cells
10
Q
CNS Glia cells
A
astrocytes- chemical clean-up (pinocytosis)
microglia- defense cells (phagocytes)
oligodendrocytes- myelinate CNS axons
11
Q
PNS glia cells
A
Schwann cells- myelinate PNS axons
12
Q
Astrocytes
A
chemical clean up (CNS)
13
Q
Microglia
A
Defense cells (CNS)
14
Q
Oligodendrocytes
A
myelinate CNS axons (CNS)
15
Q
Schwann cells
A
myelinate PNS axons (PNS)
16
Q
Neurons
A
Specialized cells that conduct messages in the form of electrical impulses
17
Q
Neuron Traits
A
Long-lived, amitotic
High metabolic rate
18
Q
Neuron Parts (4)
A
Dendrites, Soma, Axon, Axon Terminal
19
Q
Dendrites
A
Receiving Branches (catch chemical messengers)
20
Q
Soma
A
Cell body; funnel all inputs coming in and synthesize macromolecules.
21
Q
Axon
A
Long fiber that sends action potential (signal): myelinated axons are fast, have nodes (gaps of Ranvier)
22
Q
Axon Terminals
A
Knobs that secrete transmitter when AP arrives
23
Q
Functional Classes of Neurons (3)
A
Sensory
Interneurons in CNS
Motor Neurons
24
Q
Anatomy/ Structural Classes of Neurons (3)
A
Multipolar- Lots of dendrites (one axon) off soma
Bipolar- 1 Axon, 1 dendrite off soma
Unipolar- 1 axon, no dendrites off soma
25
Voltage is
a potential; separation of opposite charges
in bio, measured in mV
-Current= Voltage/ Resistance
26
Leakage Channels
are always open (not gated)
-key to resting potential
-potentials are negative as K+ leaks out through many channels
27
Gated Channels
Can be open or closed depending on...
28
Chemically Gated Channels
Opened by the presence of neurotransmitter
29
Voltage-Gated Channels
Opened by change of membrane potential
30
Mechanically gated channels
opened by physical stretch or push on the cell
(eg. pull on the skin, sound waves)
31
The Resting Membrane Potential
-Typically around -70mV
-Near K+ equilibrium as it diffuses out
-Negatively charged proteins also contribute a bit
32
Communication Signals
Neurons use changes in membrane potential as communication signals
33
A change in membrane potential from rest can either be
depolarization or hyperpolarization
34
Depolarization
-Cells charge goes towards 0mV
-Cell is "less negative"
e.g. when a cation moves into the cell
35
Hyperpolarization
-Cell becomes more negative
e.g. when a cation leaves the cell
e.g. when an anion enters the cell
36
Graded potentials are
-Voltages that vary with the stimulus strength (Spectrum)
--Tend to be local- fade with distance
e.g. EPP, post-synaptic potentials in dendrites and somas of neurons.
37
Action Potentials
-Traveling, long-distance signal on axon
-all-or-none as long as the stimulus reaches the threshold
-non-decremental (same size near soma, terminals)
Refractory Period (less excitable)= during/ after time
a)absolute refractory: another action potential is impossible
b) relative refractory: harder, but still possible to get a second action potential
38
Action Potential Phases
1. Rest Phase: Both Na+ and K+ gates shut
2: Depolarization: Na+ gates open, K+ still shut
3. Repolarization: Na+ inactivation, gates closes
4 (after) Hyperpolarization: Na+ gates still closed, K+ Gates open
39
Action Potential Phases: Rest Phase
Both Na+ and K+ gates shut
40
Action Potential Phases: Depolarization
Na+ gates open, K+ still shut
41
Action Potential Phases: Repolarization
Na+ inactivation, gates closes
42
Action Potential Phases: Hyperpolarization
Na+ gates still closed, K+ Gates open
43
absolute refractory
another action potential is impossible
44
relative refractory
harder, but still possible to get a second action potential
45
Influence of Axon Diameter on conduction velocity
The fatter the axon the faster
46
Influence of myelin on conduction velocity
The more myelin the faster= saltatory
47
Conduction velocity typical units
(meters/ second)
48
A synapse is
A junction of two neurons
49
Electrical gap junctions
Gap junctions- neurons coupled with channels allowing fast communication
50
Chemical Synapses and their parts+events
a) presynaptic terminal- AP arrives, Ca2+ enters; exocytosis of neurotransmitter
b) synaptic cleft- neurotransmitter diffuses
c) postsynaptic membrane (often dendrite membrane) its receptors catch neurotransmitters and have a graded synaptic potential (EPSP or IPSP)
51
Neurotransmitter clearance may involve
a) enzymes that cut neurotransmitter molecules (e.g. AchEsterase)
b) some transmitter just diffuses away
c) reuptake of neurotransmitters by the presynaptic terminal (e.g. serotonin reuptake proteins that are inhibited by SSRI antidepressant drugs)
52
EPSP
Excitatory- depolarization
-cations enter
-cell more likely to fire AP
53
IPSP
inhibitory-hyperpolarization
-anions enter or cations exit
-cell less likely to fire AP
54
Temporal Summation
successive inputs from same input close together in time are added
55
Spacial Summation
simultaneous inputs from multiple inputs are added
56
Neurotransmitter- Ach
a) excites skeletal muscle cells
b) inhibits cardiac muscle cells
c) memory circuits in cerebrum
57
Neurotransmitter- Biogenic Amine
a) norepinephrine- cell bodies in brain stem, long axons with terminals all over brain- alertness
b) dopamine- from basal nuclei for motor control (e.g addiction "feel good")
58
Neurotransmitter- Amino Acids
a) glutamate- excites
b) GABA- inhibit
59
Neurotransmitter- neuropeptides
e.g. endorphins- bodies own pain reliever
60
Neurotransmitter- lipids
e.g. endocanabinoid- appetite
61
Neurotransmitter- purine
inhibits neurons
e.g. caffeine inhibits adenosine receptors (blocks it from creating IPSP
62
The two main types of neurotransmitter receptors are
Ionotropic Receptors and Metabotrophic receptors
63
Ionotropic Receptors
direct- channel linked
-protein catches transmitter and acts as a chemically gated channel
64
Metabotropic Receptors
indirect
-uses G-proteins and 2nd messengers to influence... eventually... ion channels
65
diverging circuits
one (or a few) presynaptic cells communicate with many post synaptic cells (e.g. norepi)
66
converging circuits
many presynaptic cells communicate with few postsynaptic cells (e.g. grandma cells- different associations liked to grandma)
67
serial neural processing
sequential
e.g. sensory neuron-> interneuron-> motor neuron
68
parallel neural processing
simultaneous
e.g. reflex withdrawal in spinal cord happens when brain awareness happens
69
development- neural plate
ectoderm midline
70
development- neural tube
-hollow structure formed when plate folds
- will become CNS (brain + spinal cord)
71
development- neural crest
will become PNS (nerves + ganglia)
72
swellings in neural tubes and what they become- primary vesicles
forebrain, midbrain, hindbrain
73
swellings in neural tubes and what they become- secondary vesicles- forebrain
forebrain->
telencephalon-> cerebrum
diencephalon-> thylamus and hypothylamus
74
swellings in neural tubes and what they become- secondary vesicles- midbrain
midbrain-> midbrain
75
swellings in neural tubes and what they become- secondary vesicles- hindbrain
hindbrain->
metencephalon-> pons and cerebellum
mylencephalon-> medulla
76
Regions of adult brain
two lateral ventricles
third ventricle
fourth ventricle
77
ventricles
spaces filled with CSF (cerebrospinal fluid)
78
Lateral ventricles location and parts
hemispheres- inter-ventricular foramina
79
Third ventricle location and parts
diencephalon- cerebral aqueduct
80
Fourth ventricle location and parts
cerebellum- central canal (spinal cord), subarachnoid space
81
Cerebral hemispheres- cortex
outer layer of wrinkly grey matter
gyri- ridges
sulci- grooves
fissures- large sulci
82
Cerebral hemispheres- frontal lobe
in front of central sulcus
-prefrontal cortex: personality and planning
-broca's area: L side of frontal lobe- speech
-precentral gyrus: primary motor cortex
83
Cerebral hemispheres- parietal lobe
post-central gyrus: Primary somato-sensory cortex
84
Cerebral hemispheres- temporal lobe
primary auditiory cortex
85
Cerebral hemispheres- occipital lobe
primary visual cortex
86
Cerebral hemispheres- large sulci
-central sulcus: between frontal + parietal
-longitudinal fissure: between L and R hemispheres
-lateral sulcus: between temporal and frontal+ parietal lobe
-transverse fissure- between cerebrum and cerebellum
-parieto-occipital sulcus
87
white matter
made white by oligodendrocytes of tracts (bundles of axons in CNS)
88
white matter- commissures
connect L and R halves of brain
e.g. corpus callosum
89
white matter- association fibers
short, local axon
90
white matter- projection fibers
-long distance axons
--e.g. corticospinal tract axons
91
basal nuclei- corpus striatum
-caudate and putamen
-motor control
92
basal nuclei- globus pallidus- internal and external
-motor control
93
Parkinsons Disease
-cell bodies in substantia nigra that connect to axons and terminals in corpus stratum die
-tremor at rest, rigidity, difficulty starting movements
-treated with L-dopa
94
Huntingtons disease
-Basal Nuclei Die Off
-Caused by genetic mutation
-Difficulty stopping excess movement
-treat with drugs that block dopamine
95
diencephalon- thlamus
-relays info to cortex
-has nuclei within it
-lateral geniculate nucleus- to visual cortex
-medial geniculate nucleus- to auditory cortex
-intermediate mass: crosses midline
96
diencephalon- hypothalamus
-below thalamus, above pituitary
-motivation/ drive reduction (sleep, hunger, sex drive)
-controls pituitary through infundibulum
-important effects on autonomic nervous system
97
diencephalon- epithalamus
includes pineal gland (melatonin-sleeeppyyy)
98
Where is the midbrain located
Between Pons and Diencephalon
99
Midbrain includes....
-cerebral peduncles: front
-cerebral aqueduct: center
-superior collicili: visual reflex- back
-inferior collicili: auditory reflex- back
-substantia nigra- middle
100
Pons "bridge"
-fiber tract
-nuclei for nerves 5-8
101
medulla oblongata
-pyramids of medulla- rides in front with motor cortex axons
-decussation- axons cross so one side of motor cortex controls the other side of the body
-cardiovasular and respiratory control nuclei
102
Cerebellum consists of...
-Cortex "folia" (ridges)
-arbor vitae- white matter
-deep cerebellar nuclei
103
Cerebellum- Cortex: "Folia"
-ridges
-2 hemispheres with vermis on midline
--anterior lobe, posterior lobe, small flocculonodular lobe
104
Cerebellum- Arbor Vitae- white matter
myelinated axons going to and from cerebral cortex
105
Cerebellum- Deep cerebellar nuclei
Cell bodies that have axons exciting cerebellum w/ terminals in thalamus and brainstem for ipsilateral motor control (same side motor control)
106
The limbic system functions in
emotion
107
Limbic system consists of
amygdala
hypothalamus
cingulate gyrus
108
Amygdala
-"almond" deep in temporal lobe
-fear and aggression
109
Hypothalamus
-desire/satisfaction
110
Cingulate Gyrus
-ridge above the corpus callous
-pain, resolving internal conflict
111
How many stages of sleep do you go through in one night
4-5, measured by EEG
112
Sleep Stage 1
Start to relax- alpha waves
113
Sleep Stage 2
Alpha waves, sleep spindle
114
Sleep Stage 3
Deep Sleep= slow waveform sleep (delta, theta waves)
115
Sleep Stage 4
Deepest sleep= Mostly Delta Waves
116
REM Sleep
Rapid eye movement
-high frequency beta waves
-dreams w/ story; motor neurons inhibited
117
Stages of memory
Short-term and long-term
118
Short-term memory
seconds- limited capacity
119
long-term memory
has to be "consolidated" huge capacity
120
Categories of memory
Declarative- what
procedural- how
121
Declarative memory
"what"
-recal of facts
--H.M. lost the ability to consolidate declarative memories after his hipocampus was removed
122
Procedural memory
"how"
-skill memory
--H.M. kept that
123
Brain structures involved in delarative memory
hippocamupus (ach neurotransmitter) and basal forebrain
124
Brain structures involved in procedural memory
-basal nuclei-> dopamine
-premotor cortex
125
Protection of CNS- Meninges= "membranes"
PAD the CNS
-Pia matter
-arachnoid matter
-dura matter
126
Pia Matter
inner thin layer
127
Arachnoid Matter
Middle spider-web like layer
-space under it (above pia) has CSF
128
Dura Matter
Outer, thick membrane- with periosteal and meningeal layer
e.g. falx cerebri- longitudinal fissure
falx cerebri- vermis
tentorium cerabelli- transverse fissure
129
C.S.F cerebrospinal fluid
a) plasma like
b) made by choroid plexus in ventricles
c) flows into ventricles, subarachnoid space, central canal
d) absorbed into blood at granulations or dural sinuses
130
what makes CSF and where
made by choroid plexus in ventricles
131
Where does CSF go
ventricles, subarachnoid space, and central canal
132
where is CSF absorbed
absorbed into blood at granulations or dural sinuses
133
blood brain barrier
-protects brain chemistry
-consists of tightly sealed cappilaries (many tight junctions) reinforced by astrocytes
-not absolute
134
blood brain barrier function
protect brain chemistry
135
blood brain barrier consists of
tightly sealed cappilaries (many tight junctions) reinforced by astrocytes
136
spinal cord is consists of
nervous tissue
137
spinal cord extent
-from foramen magnum to L1 vertebrae
-inferior end: conus medullaris
-below conus is cauda equina- nerve bundle
138
Spinal cord enlargements
cervical enlargement: serves upper limbs
lumbar enlargement: for lower limbs
139
spinal cord in cross section
-central grooves
-white matter
-grey matter
140
SC in cross section central grooves
-anterior median fissure
-posterior median sulcus
141
SC in cross section grey matter
i) grey commissure
ii) dorsal horns- interneurons for somatic sensation
iii) ventral horns- motor neuron somas
iv) lateral horns- only in T and L spinal cord ---sypathetic n.s. neurons
142
SC in cross section white matter- main columns (funiculi)
-contains tracts- bundles of axons
-anterior
-posterior
-lateral
143
SC in cross section white matter- ascending tracts within columns
- dorsal columns contain fasciculus gracilis (lower limb info) and fasciculus cunetus (upper limb info) which both carry light touch (sensory) and proprioception
-anterolateral white matter contains spinothalamic tract that carries pain and temperature info into brain
144
SC in cross section white matter- descending tract
-lateral corticospinal tract= pyramidal tract
-from motor cortex to spinal cord for control of fine movements (distal muscles)
145
CN I
Olfactory- smell
146
CN II
Optic- See
147
CN III
Oculomotor- Moves eyes around
148
CN IV
Trochlear- moves eye
149
CN V
trigeminal- sensation of face, chew
150
CN VI
Abducens- moves eye laterally
151
CN VII
Facial- facial expression, taste
152
CN VIII
Vestibulocochlear- balance, hearing
153
CN IX
glossopharyngeal- sensory+ motor for tongue and throat
154
CN X
Vagus- PNS- autonomic rest/ digest
155
CN XI
Accessory- neck/ shoulder m.
156
CN XII
Hypoglossal- controls tongue m.
157
