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Anatomy and Physiology > Ch12 Nervous Tissue > Flashcards

Ch12 Nervous Tissue Flashcards

1
Q

_______ & ______ system maintain internal coordination

A

ENDOCRINE & NERVOUS system maintain internal coordination

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2
Q

endocrine system uses _____ vs nervous system uses ______

A

endocrine system uses HORMONES vs nervous system uses ELECTRICAL & CHEMICAL SIGNALS

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3
Q

Nervous System

  • _____ organs receive ____
  • ____ & _____ process this ____, determine ______
  • ____ & ___ issues ____ to ____/____ to _____
A

Nervous System

  • SENSE organs receive INFORMATION
  • BRAIN & SPINAL CORD process this INFORMATION, determine APPROPRIATE RESPONSE
  • BRAIN & SPINAL CORD issues COMMANDS to MUSCLES/GLANDS to CARRY OUT RESPONSE
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4
Q

Name the 2 major anatomical subdivisions of the nervous system

A
  1. Central Nervous System (CNS)
  2. Peripheral Nervous System (PNS)
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5
Q

The CNS is made up of the _____ that are _____ in ____ coverings

The PNS is made of of ____ which are bundles of _____ (___) wrapped in ____ and also made up of _____ which are _____ in the ____ where _________ are

A

The CNS is made up of the BRAIN & SPINAL CORD that are ENCLOSED in BONY coverings

The PNS is made of of NERVES which are bundles of NERVE FIBERS (AXONS) wrapped in CT and also made up of GANGLION which are SWELLING in the NERVE where NEURON CELL BODIES are

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6
Q

What are the functional divisions of the PNS?

A
  • sensory (afferent - incoming) division
  • motor (efferent - outgoing) division
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7
Q

PNS

  1. Sensory (afferent) division - carries ______ to ____
  • somatic: signals from ___, ___, ___, & ___
  • visceral: signs from ____
  1. Motor (efferent) division - carries ___ from ___ to ___/___ (effectors) to effect ____
  • somatic: signals to _____
  • visceral: _____ (_____ & ____)
A

PNS

  1. Sensory (afferent) division - carries SENSORY SIGNAL RECEPTORS to CNS
  • somatic: signals from SKIN, MUSCLES, BONES, & JOINTS
  • visceral: signs from VISCERA
  1. Motor (efferent) division - carries SIGNALS from CNS to GLANDS/MUSCLES (effectors) to effect RESPONSE
  • somatic: signals to SKELETAL MUSCLES
  • visceral: AUTONOMIC NERVOUS SYSTEM (ANS) (SYMPATHETIC & PARASYMPATHETIC)
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8
Q

Name and describe the properties of neurons

A
  • Secretion - chemical neurotransmitters secreted, stimulate next cell
  • Excitability (irritability) - respond to environmental changes (stimuli)
  • Conductivity - neurons respond to stimuli by producing electrical signals, quickly conducted to other cells
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9
Q

Functional Classes of Neurons

  • ______ (afferent) neurons - specialized to detect _____ (____ information from _____ to ____)
  • _____ (association neurons) - recieve ___ from many _____, carry out ____
  • ____ (efferent) neurons - sends ____ out to ____ and ___ (effectors) - conducts ____ ____ from ____
A

Functional Classes of Neurons

  • SENSORY (afferent) neurons - specialized to detect STIMULI (TRANSMIT information from ORGANS to CNS)
  • INTERNEURONS (association neurons) - recieve SIGNALS from many NEURONS, carry out INTEGRATIVE FUNCTION
  • MOTOR (efferent) neurons - sends SIGNALS out to MUSCLES and GLANDS (effectors) - conducts SIGNALS AWAY from CNS
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10
Q

Interneurons ___, ___, retrieve _____, “decide” how _____

___% of all ____ = interneurons

A

Interneurons PROCESS, STORE, retrieve INFORMATION, “decide” how BODY RESPONDS

90% of all NEURONS = interneurons

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11
Q

Basic Neuron Structure

  1. _____ - cell body
  2. ____ (nerve fiber) - originates from ____
  • relatively ____ (collaterals)
  • branch extensively at _____
  • specialized for _____
  1. _____ - branches of ____
  • recieve signals from _____
  • more _____ = more _____ it can _____ and ____
A

Basic Neuron Structure

  1. SOMA - cell body
  2. AXON (nerve fiber) - originates from AXON HILLOCK
  • relatively UNBRANCHED (collaterals)
  • branch extensively at DISTAL ENDS
  • specialized for RAPID CONDUCTION
  1. DENDRITES - branches of SOMA
  • recieve signals from OTHER NEURONS
  • more DENDRITES = more INFORMATION it can RECIEVE and PROCESS
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12
Q

Neuron Variations (polar = how many extensions come from that soma)

  1. Unipolar neuron
  • ___ process leading ____ from soma
  • sensory from ___/___ to ____
  1. Bipolar neuron
  • ___ axon, ___ dendrite
  • _____ cells, ___, inner ___
  1. Multipolar neuron
  • ___ axons, ___ dendrites
  • most ___
  • most neurons in ____ and ____
A

Neuron Variations (polar = how many extensions come from that soma)

  1. Unipolar neuron
  • SINGLE process leading AWAY from soma
  • sensory from SKIN/ORGANS to SPINAL CORD
  1. Bipolar neuron
  • 1 axon, 1 dendrite
  • OLFACTORY cells, RETINA, inner EAR
  1. Multipolar neuron
  • 1 axons, MULTIPLE dendrites
  • most COMMON
  • most neurons in BRAIN and SPINAL CORD
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13
Q

Atonal Transport

  • Many ____ made in ____ must be transported to _____ and ____ terminal
  • Why? To repair _____, serve as gated ______, serve as ____ or ____
A

Atonal Transport

  • Many PROTEINS made in SOMA must be transported to AXON and AXON TERMINAL
  • Why? To repair AXOLEMMA, serve as gated ION-CHANNEL, serve as ENZYMES or NEUROTRANSMITTERS
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14
Q

What is anterograde transport?

A

Movement down axon away from soma

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15
Q

What is retrograde transport?

A

Movement up axon toward soma

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16
Q

What are the types of axonal transport?

A

Fast axonal transport and slow axonal transport

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17
Q

Axonal Transport

Fast Axonal Transport

  • fast anterograde transport =
  • fast retrograde transport = for…

Slow Axonal Transport

  • always…
  • moves _____ and new _____ down ___ during ___ and _____
A

Axonal Transport

Fast Axonal Transport

  • fast anterograde transport = SYNAPTIC VESICLES, ORGANELLES, SMALL MOLECULES, ENZYMES
  • fast retrograde transport = for RECYCLED MATERIALS OR PATHOGENS

Slow Axonal Transport

  • always ANTEROGRADE
  • moves CYTOSKELETON COMPONENTS and new AXOPLASM down AXON during REPAIR and REGENERATION
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18
Q

Neuroglia (supportive ___)

~1trillion neurons in _____ yet outnumbered by ____ by as much as ____

  • supports &…
  • binds…
  • embryology:

4 types in…

A

Neuroglia (supportive CELLS)

~1trillion neurons in NERVOUS SYSTEM yet outnumbered by GLIA by as much as 50:1

  • supports & PROTECTS NEURONS
  • bindS NEURONS TOGETHER, FORM FRAMEWORK
  • embryology: GUIDE MIGRATING NEURONS

4 types in CENTRAL NERVOUS SYSTEM

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19
Q

What are the 4 types of neuroglia in CNS?

A
  • Ependymal Cells
  • Microglia
  • Oligodendrocytes
  • Astrocytes
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20
Q

Types of Neuroglias

  • ependymal cells - line _____ of ___ secretes ____
  • microglia - small _____; ______ cellular ____
  • oligodendrocytes - wraps around _____ forming _____ that ____ signal conduction
A

Types of Neuroglias

  • ependymal cells - line INTERNAL CAVITIES of BRAIN secretes CSF
  • microglia - small MACROPHAGES; PHAGOCYTIZE cellular DEBRIS
  • oligodendrocytes - wraps around NERVE FIBER (AXON) forming INSULATING LAYER that SPEEDS signal conduction
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21
Q

Astrocytes

most abundant ____ in ___

extensions (____) contract ____, form _____ barrier

convert blood ___ to ____

secrete _______ to promote neuron _____ and ____ formation

form _____ (sclerosis) and fill empty space when ____

A

Astrocytes

most abundant GLIAL CELL in CNS

extensions (PERIVASCULAR FEET) contract CAPILLARIES, form BLOOD-BRAIN barrier

convert blood GLUCOSE to LACTATE

secrete NERVE GROWTH FACTORS to promote neuron GROWTH and SYNAPSE formation

form SCAR TISSUE (sclerosis) and fill empty space when NEURON IS DAMAGED

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22
Q

Types of Neuroglia - PNS

1.Schwann Cells

  • envelope _____ in ___
  • produce _____similar to those produced by _______ in ___
  • assists in _____ of ______ fibers
  1. Satellite Cells

surrounds _____ of ______ cells in ganglia of ____

A

Types of Neuroglia - PNS

1.Schwann Cells

  • envelope NERVE FIBERS in PNS
  • produce MYELIN SHEATH similar to those produced by OLIGODENDROCYTES in CNS
  • assists in REGENERATION of DAMAGED fibers
  1. Satellite Cells

surrounds NEUROSOMA of UNIPOLAR cells in ganglia of PNS

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23
Q

Brain Tumors

  • tumors - masses of…
  • mature ____ have little/no capacity for ____, seldom form ___

Brain tumors arise from

  • meninges (protective ____ of ___)
  • metastasis (from _____ tumors in other ___)
  • glial cells (____ active)

Gliomas grow ____ - highly ____

  • _____ barrier decreases effectiveness of _____
  • treatment: surgery or ____
A

Brain Tumors

  • tumors - masses of RAPIDLY UNCONTROLLED DIVIDING CELLS
  • mature NEURONS have little/no capacity for MITOSIS, seldom form TUMORS

Brain tumors arise from

  • meninges (protective MEMBRANES of CNS)
  • metastasis (from NONNEURONAL tumors in other ORGANS)
  • glial cells (MITOTICALLY active)

Gliomas grow RAPIDLY - highly MALIGNANT

  • BLOOD-BRAIN barrier decreases effectiveness of CHEMOTHERAPY
  • treatment: surgery or RADIATION
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24
Q

Myelin Sheath

______ layer around _____

  • ______ in CNS, ______ in PNS
  • ______ membrane of ____ cells
  • ____% protein / ___% ____ (looks white)
  • production = _______ - from ____ development through late ____

In PNS, ____ cells spirals around…

  • neurilemma: thick, _____ coil of myelin sheath
  • basal lamina = ____ to neurilemma, then _____ = thin layer of ______
A

Myelin Sheath

INSULATING layer around NERVE FIBER

  • OLIGODENDROCYTES in CNS, SCHWANN CELLS in PNS
  • PLASMA membrane of GLIAL cells
  • 80% protein / 20% LIPID (looks white)
  • production = MYELINATION - from FETAL development through late ADOLESCENCE

In PNS, SCHWANN cells spirals around ONE NERVE FIBER

  • neurilemma: thick, OUTERMOST coil of myelin sheath
  • basal lamina = EXTERNAL to neurilemma, then ENDONEURIUM = thin layer of FIBROUS CT
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25
Q

Myelin Sheath

In CNS, _____ myelinate several _____ in immediate vicinity

  • push newer layers of ____ under older ones; so _____ spirals ____ towards ____

Myelin sheath is ____

  • nodes of ranvier = gap…
  • axon hillock + initial segment (short section before 1st ____) = ___ zone - important role in initiating….
A

Myelin Sheath

In CNS, OLIGODENDROCYTES myelinate several NERVE FIBERS in immediate vicinity

  • push newer layers of MYELIN under older ones; so MYELINATION spirals INWARD towards NERVE FIBER

Myelin sheath is SEGMENTED

  • nodes of ranvier = gap BETWEEN SEGMENTS
  • axon hillock + initial segment (short section before 1st SCHWANN CELL) = TRIGGER zone - important role in initiating NERVE SIGNAL
26
Q

What are 2 degenerative disorders of myelin sheath?

A
  • Multiple sclerosis (MS)
  • Tay-Sachs disease
27
Q

Schwann cells hold small _____ in grooves on their _____ with only one _____

A

Schwann cells hold small NERVE FIBERS in grooves on their SURFACE with only one MEMBRANE WRAPPING

28
Q

Conduction of Speed Nerve Fibers

  • ______ occurs along surface
  • Speed depends on ______ of ___
  • larger ____ have more ____, conduct ____

presence of myelin

  • small, ______ fibers
  • small, ______ fibers
  • large, ______ fibers
A

Conduction of Speed Nerve Fibers

  • SIGNAL CONDUCTION occurs along surface
  • Speed depends on DIAMETER of FIBER
  • larger FIBERS have more SURFACE AREA, conduct RAPIDLY

presence of myelin

  • small, UNMYELINATED fibers
  • small, MYELINATED fibers
  • large, MYELINATED fibers
29
Q

Regeneration of Nerve Fiber (PNS only)

  • occurs if ___ and “___” intact
  • distal end of ____ and _____ degenerate (soma ____, ___ moves off-center)
  • ______ sprouts several growth processes
  • ______ guides lucky sprout back to _____ destination (____ cells produce nerve growth factors)
  • ___ returns to normal
A

Regeneration of Nerve Fiber (PNS only)

  • occurs if SOMA and “TUBE” intact
  • distal end of AXON and MYELIN SHEATH degenerate (soma SWELLS, NUCLEUS moves off-center)
  • AXON STUMP sprouts several growth processes
  • REGENERATION TUBE guides lucky sprout back to ORIGINAL destination (SCHWANN cells produce nerve growth factors)
  • SOMA returns to normal
30
Q

There is no regeneration in

A

CNS

31
Q

Electrical Potentials and Currents

S. Ramon y Cajal’s neuron doctrine: nervous pathway not continuous “____”, but series of ____ separated by ____ called ____

  • electrical potential - difference in _____ of charged particles between one point and another
  • electrical current - ___ of charged particles from one point to another

neurons are _____ (charge difference ___mV across ______)

A

Electrical Potentials and Currents

S. Ramon y Cajal’s neuron doctrine: nervous pathway not continuous “WIRE”, but series of CELLS separated by GAPS called SYNAPSES

  • electrical potential - difference in CONCENTRATION of charged particles between one point and another
  • electrical current - FLOW of charged particles from one point to another

neurons are POLARIZED (charge difference -70mV across PLASMA MEMBRANE)

32
Q

Resting Membrane Potential (RMP)

  • exists because of _________ between ECF and ICF

results from 3 factors

  1. ions diffuse down their ________ through membrane
  2. plasma membrane is selectively _____
  3. _____ attraction of cations and anions
A

Resting Membrane Potential (RMP)

  • exists because of UNEQUAL ELECTROLYTE DISTRIBUTION between ECF and ICF

results from 3 factors

  1. ions diffuse down their CONCENTRATION GRADIENT through membrane
  2. plasma membrane is selectively PERMEABLE
  3. ELECTRICAL attraction of cations and anions
33
Q

RMP

  • plasma membrane is ___ permeable to ___ than any other ion (___ is ~40x as concentrated in ICF as in ___)
  • Cytoplasmic anions ____ escape due to ___ or ____ (PO4-2, SO4-2, organic acids, proteins)
  • membrane much ____ permeable to ___ (___ ~12x as concentrated in ECF as ___)
  • Na+/K+ pumps out ___ Na+ for every ___ K+ it brings in (works ______, requires great deal of _____ —- much ____ and ____ needed)
A

RMP

  • plasma membrane is MORE permeable to K+ than any other ion (K+ is ~40x as concentrated in ICF as in ECF)
  • Cytoplasmic anions CANNOT escape due to SIZE or CHARGE (PO4-2, SO4-2, organic acids, proteins)
  • membrane much LESS permeable to Na+ (Na+ ~12x as concentrated in ECF as ICF)
  • Na+/K+ pumps out 3 Na+ for every 2 K+ it brings in (works CONTINUOUSLY, requires great deal of ATP —- much GLUCOSE and O2 needed)
34
Q

Na+ concentrated _____ (___)

K+ concentrated ____ (___)

A

Na+ concentrated OUTSIDE (ECF)

K+ concentrated INSIDE (ICF)

35
Q

Local Potentials

  • Disturbances in ______
  • Occurs when ____ stimulated
  • Depolarization: ____ potential across ____ membrane because opened ___ channels - less ___ value
  • ___ rushes down its concentration gradient
  • ___ diffuses short ____ inside ____ membrane, producing ______ change in ____ = local potential
A

Local Potentials

  • Disturbances in MEMBRANE POTENTIAL
  • Occurs when NEURON stimulated
  • Depolarization: DECREASE potential across CELL membrane because opened Na+ channels - less NEGATIVE value
  • NA+ rushes down its concentration gradient
  • Na+ diffuses short DISTANCE inside PLASMA membrane, producing SHORT-RANGE change in VOLTAGE = local potential
36
Q

Local Potentials

Differences: local potentials vs action potentials

  • graded: vary in _____ with ____ strength
  • decremental: get _____ the ____ they ____
  • reversible: when ____ ceases, ___ diffusion out of ___, returns ___ to normal _____
  • either excitatory or inhibitory: ex) glycine makes membrane potential more ____ = _____
A

Local Potentials

Differences: local potentials vs action potentials

  • graded: vary in MAGNITUDE with STIMULUS strength
  • decremental: get WEAKER the FARTHER they SPREAD
  • reversible: when STIMULATION ceases, K+ diffusion out of CELL, returns CELL to normal RESTING POTENTIAL
  • either excitatory or inhibitory: ex) glycine makes membrane potential more NEGATIVE = HYPERPOLARIZED
37
Q

Action Potentials

  • ____ change in _____ produced where high density of _____ channels occur
  • if threshold potential (___mV) is reached, voltage-gated __ channels open (___ enters causing ____)
  • past 0mV, ___ channels close =
  • slow __ gates fully open ___ exits ____ cell
  • negative overshoot produces _____ = _____ exiting of ___
A

Action Potentials

  • DRAMATIC change in MEMBRANE produced where high density of VOLTAGE-GATED channels occur
  • if threshold potential (-55mV) is reached, voltage-gated Na+ channels open (Na+ enters causing DEPOLARIZATION)
  • past 0mV, Na+ channels close = DEPOLARIZATION
  • slow K+ gates fully open K+ exits REPOLARIZING cell
  • negative overshoot produces HYPERPOLARIZATION = EXCESSIVE exiting of K+
38
Q

Action Potentials

  • called “___”

characteristics

  • follow _____ law (______ either open or don’t)
  • nondecremental: do not get ____ with ____
  • irreversible: once started, goes to ___, ___ be stopped
A

Action Potentials

  • called “SPIKE”

characteristics

  • follow ALL-OR-NONE law (VOLTAGE GATES either open or don’t)
  • nondecremental: do not get WEAKER with DISTANCE
  • irreversible: once started, goes to COMPLETION, CANNOT be stopped
39
Q

Action Potential Spike Summary

  • ___ of ions
  • removal of _____ by astrocytes
  • only thin layer of ____ close to ___ moved during AP
A

Action Potential Spike Summary

  • DIFFUSION of ions
  • removal of ECF K+ by astrocytes
  • only thin layer of IONS close to MEMBRANE moved during AP
40
Q

Refractory Period - period of ___ to ____

Absolute refractory period

  • as long as ____ gates __
  • no ____ will trigger AP

Relative refractory period

  • as long as ___ open
  • only especially ____ stimulus will _____ AP
  • refractory period refers only to _____ of ____ at one time (quickly ____)
A

Refractory Period - period of RESISTANCE to STIMULATION

Absolute refractory period

  • as long as Na+ gates OPEN
  • no STIMULUS will trigger AP

Relative refractory period

  • as long as K+ open
  • only especially STRONG stimulus will TRIGGER NEW AP
  • efractory period refers only to SMALL PATCH of MEMBRANE at one time (quickly RECOVERS)
41
Q

Signal Conduction - Unmyelinated Nerve Fibers

AP from ______ zone causes ___ to enter axon (impulse begins)

  • _______ excited voltage-regulated gates immediately distal to ____
  • chain reaction of _________ of voltage-gated ___ channels down the entire length of axon
  • impulse (_________) travels 2m/sec
A

Signal Conduction - Unmyelinated Nerve Fibers

AP from TRIGGER zone causes Na+ to enter axon (impulse begins)

  • DEPOLARIZATION excited voltage-regulated gates immediately distal to AP
  • chain reaction of SEQUENTIAL OPENING of voltage-gated Na+ channels down the entire length of axon
  • impulse (NON-DECREMENTAL) travels 2m/sec
42
Q

Saltatory Conduction - Myelinated Nerve Fibers

  • voltage-gated channels needed for ____
  • fast ____ diffusion occurs between ___
  • signal seems to jump from node to ___
  • much faster than _______ fibers
A

Saltatory Conduction - Myelinated Nerve Fibers

  • voltage-gated channels needed for APs
  • fast Na+ diffusion occurs between NODES
  • signal seems to jump from node to NODE
  • much faster than UNMYELINATED fibers
43
Q

Synapses

  • first neuron releases _______ onto second that responds to it
  • 1st neuron in signal path = ______ (_______ neurotransmitters)
  • 2nd neuron = _______ (_______ neurotransmitters)
A

Synapses

  • first neuron releases NEUROTRANSMITTER onto second that responds to it
  • 1st neuron in signal path = PRESYNAPTIC NEURON (RELEASES neurotransmitters)
  • 2nd neuron = POSTSYNAPTIC NEURON (RESPONDS TO neurotransmitters)
44
Q

Synapses

  • synapses may be _____, _____, or _____
  • number of synapses on ________ cell quite variable
  • _______ neuron has ~10,000
  • in _____, 1 neuron can have as many as many as 100,000 synapses
A

Synapses

  • synapses may be AXODENDRITIC, AXOSOMATIC, or AXOAXONIC
  • number of synapses on POST-SYNAPTIC cell quite variable
  • SPINAL MOTOR neuron has ~10,000
  • in CEREBELLUM, 1 neuron can have as many as many as 100,000 synapses
45
Q

Discovery of Neurotransmitters

  • ___________ between neurons discovered through histological observations
  • Otto Loewi (1921) demonstrated that _____ communicate by ________ “______ synapses”
  • flooded exposed _____ of 2 frogs with ____
  • stimulated _____ nerve of first frog, heart ____
  • removed saline from that frog found it _____ heart of second frog

named it Vagusstoffe “_____ substance” —- later rename ______ 1st known neurotransmitter

A

Discovery of Neurotransmitters

  • ___________ between neurons discovered through histological observations
  • Otto Loewi (1921) demonstrated that _____ communicate by ________ “______ synapses”
  • flooded exposed _____ of 2 frogs with ____
  • stimulated _____ nerve of first frog, heart ____
  • removed saline from that frog found it _____ heart of second frog

named it Vagusstoffe “_____ substance” —- later rename ______ 1st known neurotransmitter

46
Q

Discovery of Neurotransmitters

  • ______ synapses do exist
  • _____ junctions join adjacent cells
  • advantage: ____ transmission (_____ and ____ muscle, some neurons)
  • disadvantage: cannot integrate _____ /make ______
  • ability reserved for ____ synapses in which ____ communicate by releasing _____
A

Discovery of Neurotransmitters

  • ELECTRICAL synapses do exist
  • GAP junctions join adjacent cells
  • advantage: QUICK transmission (CARDIAC and SMOOTH muscle, some neurons)
  • disadvantage: cannot integrate INFORMATION /make DECISIONS
  • ability reserved for CHEMICAL synapses in which NEURONS communicate by releasing NEUROTRANSMITTERS
47
Q

Structure of a Chemical Synapse

  • presynaptic neurons have vesicles with ____
  • postsynaptic have ____ and ligand-regulated ___ channels
A

Structure of a Chemical Synapse

  • presynaptic neurons have vesicles with NEUROTRANSMITTER
  • postsynaptic have RECEPTORS and ligand-regulated ION channels
48
Q

Neurotransmitters

4 major categories (by _____ composition)

  • acetylcholine - from from ____ acid + choline
  • amino acid neurotransmitters ex. ____
  • monoamines - made by removal of -COOH group from AA ex. epinephrine, _____, ____ (catecholamines), histamine, _____
  • neuropeptides
A

Neurotransmitters

4 major categories (by CHEMICAL composition)

  • acetylcholine - from from ACETIC acid + choline
  • amino acid neurotransmitters ex. GLYCINE
  • monoamines - made by removal of -COOH group from AA ex. epinephrine, NOREPINEPHRINE, DOPAMINE (catecholamines), histamine, SEROTONIN
  • neuropeptides
49
Q

Neuropeptides

  • 2-40 AA
  • act at ____ concentrations
  • _____ lasting effects
  • stored in ______ as larger _____ granules (dense-core vesicles)
  • some function as _____ or neuromodulators
  • some released from ______ tissue (gut-brain peptides cause food cravings (Ghrelin)
A

Neuropeptides

  • 2-40 AA
  • act at LOWER concentrations
  • LONGER lasting effects
  • stored in AXON TERMINAL as larger SECRETORY granules (dense-core vesicles)
  • some function as HORMONES or neuromodulators
  • some released from NONNEURAL tissue (gut-brain peptides cause food cravings (Ghrelin)
50
Q

Synaptic Transmission

3 kinds of synapses with different modes of ____

  • excitatory _____ synapse ex) ___
  • inhibitory ______ synapse ex) ____
  • excitatory ______ synapse ex) ___
A

Synaptic Transmission

3 kinds of synapses with different modes of ACTION

  • excitatory CHOLINERGIC synapse ex) ACh
  • inhibitory GABA-energic synapse ex) GABA
  • excitatory ADRENERGIC synapse ex) NE
51
Q

Excitatory Cholinergic Synapse - ACh

  • signal opens __________ channels in synaptic ____
  • triggers release of _____; crosses ____
  • ACh receptors trigger opening of ___ channels, producing ____ potential (_____ potential)
    • when -55mV triggers AP in _____ neuron
A

Excitatory Cholinergic Synapse - ACh

  • signal opens VOLTAGE-GATED CALCIUM channels in synaptic KNOB
  • triggers release of ACh; crosses SYNAPSE
  • ACh receptors trigger opening of Na+ channels, producing LOCAL potential (POSTSYNAPTIC potential)
    • when -55mV triggers AP in POSTSYNAPTIC neuron
52
Q

Inhibitory GABA-ergic Synapse

  • signal triggers release of _____ into _____ cleft
  • GABA receptors trigger opening of ____ channels, producing ______ (inside more ___ than RMP)
  • _____ neuron is inhibited, less likely to reach ____
A

Inhibitory GABA-ergic Synapse

  • signal triggers release of GABA into SYNAPTIC cleft
  • GABA receptors trigger opening of CI- channels, producing HYPERPOLARIZATION (inside more NEGATIVE than RMP)
  • POSTSYNAPTIC neuron is inhibited, less likely to reach THRESHOLD
53
Q

Excitatory Adrenergic Synapse

  • employs ________ aka noradrenaline
  • acts through __________ system (cAMP) – ______ associated with G protein, which activates adenylate cyclase, coverts ___ to ___
  • ___ response than cholinergic and GABA-ergic synapses
  • advantage = ______ amplification
A

Excitatory Adrenergic Synapse

  • employs NOREPINEPHRINE (NE) aka noradrenaline
  • acts through SECOND MESSENGER system (cAMP) – RECEPTOR associated with G protein, which activates adenylate cyclase, coverts ATP to cAMP
  • SLOWER response than cholinergic and GABA-ergic synapses
  • advantage = ENZYME amplification
54
Q

Cessation of Signal

  • Mechanisms to _____ stimulation
  1. neurotransmitter escapes into _____ = ____ (_____ return it to neurons)
  2. synaptic knob reabsorbs AA and monoamines by ______= ______
  3. acetylcholinesterase breaks down ____ = _______
  • Choline reabsorbed and _____
A

Cessation of Signal

  • Mechanisms to TURN OFF stimulation
  1. neurotransmitter escapes into ECF = DIFFUSION (ASTROCYTES return it to neurons)
  2. synaptic knob reabsorbs AA and monoamines by ENDOCYTOSIS = REUPTAKE
  3. acetylcholinesterase breaks down ACh = DEGRADATION
  • Choline reabsorbed and RECYCLED
55
Q

Neuromodulators

  • modify synaptic ____
  1. raise or lower ___ of ____
  2. alter rate of neurotransmitter synthesis, ______, ______, or _____
  • ex) enkephalins - neuromodulator ____
  • small ____ that inhibit ___ signals
A

Neuromodulators

  • modify synaptic TRANSMISSION
  1. raise or lower NUMBER of RECEPTORS
  2. alter rate of neurotransmitter synthesis, RELEASE, REUPTAKE, or BREAKDOWN
  • ex) enkephalins - neuromodulator FAMILY
  • small PEPTIDES that inhibit PAIN signals
56
Q

Neural Integration

  • more synapses = greater ___________ capability
  • chemical synapses = _________ components of ____ system
  • ability to _____, ____, and ____ information due to neural integration
A

Neural Integration

  • more synapses = greater INFORMATION-PROCESSING capability
  • chemical synapses = DECISION-MAKING components of NERVOUS system
  • ability to PROCESS, STORE, and RECALL information due to neural integration
57
Q

Postsynaptic Potentials - EPSP

  • neural integration - based on postsynaptic potentials produced by _____

excitatory postsynaptic potential (EPSP)

  • positive voltage change causing postsynaptic neuron to be more likely to ____ — results from ___ flowing into cell cancelling some ____ charge on ___ of membrane
  • glutamate and aspartate = ____ brain neurotransmitters, produce EPSPs
  • ACh and NE may ___ or ___ depending on receptor on target cell
A

Postsynaptic Potentials - EPSP

  • neural integration - based on postsynaptic potentials produced by NEUROTRANSMITTERS

excitatory postsynaptic potential (EPSP)

  • positive voltage change causing postsynaptic neuron to be more likely to FIRE — results from Na+ flowing into cell cancelling some NEGATIVE charge on INSIDE of membrane
  • glutamate and aspartate = EXCITATORY brain neurotransmitters, produce EPSPs
  • ACh and NE may EXCITE or INHIBIT depending on receptor on target cell
58
Q

Temporal and Spatial Summation

Net postsynaptic potentials in trigger zone

  • firing depends on net input of other ___
  • typical EPSP voltage = 0.5mV, lasts 20msec
  • 30 EPSPs needed to reach ____

Temporal Summation

  • single synapse recieved many EPSPs in ____

Spatial Summation

  • single synapse receives many EPSPs from ____
A

Temporal and Spatial Summation

Net postsynaptic potentials in trigger zone

  • firing depends on net input of other CELLS
  • typical EPSP voltage = 0.5mV, lasts 20msec
  • 30 EPSPs needed to reach THRESHOLD

Temporal Summation

  • single synapse recieved many EPSPs in SHORT TIME

Spatial Summation

  • single synapse receives many EPSPs from MANY CELLS
59
Q

Presynaptic Facilitation

One presynaptic neuron _____ another:

  • 1st neuron releases NT, opens voltage-gated ____ channels on 2nd neuron

Enhances _____ release

A

Presynaptic Facilitation

One presynaptic neuron FACILITATES:

  • 1st neuron releases NT, opens voltage-gated Ca+2 channels on 2nd neuron

Enhances NEUROTRANSMITTER release

60
Q

Presynaptic Inhibition

One presynaptic neuron ____ another:

  • 1st neuron releases inhibitory ___, prevents voltage-gated ___ channels on 2nd neuron from opening
  • releases ___/no _______
A

Presynaptic Inhibition

One presynaptic neuron SUPPRESSES another:

  • 1st neuron releases inhibitory GABA, prevents voltage-gated Ca+2 channels on 2nd neuron from opening
  • releases LESS/no NEUROTRANSMITTER

Anatomy and Physiology (13 decks)

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