Chapter 2A

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Flashcards on Chapter 2A, created by Madeline Luedke on 26/09/2016.
Madeline Luedke
Flashcards by Madeline Luedke, updated more than 1 year ago
Madeline Luedke
Created by Madeline Luedke over 7 years ago
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Question Answer
Two kinds of cells in nervous system 1. neurons 2. glial cells
Neurons nerve cells, specialized for reception, conduction, and transmission of electrochemical signals
Glial cells support, protect, and insulate • outnumber neurons 10:1
Four types of neurons 1. unipolar 2. bipolar 3. multipolar 4. multipolar interneuron
sensory neurons • sensitive to the environment • convert incoming physical stimuli to an electrical signal, then send it to CNS
interneurons nerve cells within the CNS (go in between)
Motor neurons transmit outgoing signals from CNS to muscles, to make behavioral response
3 common features of neurons 1. dendrites: branches, detectors 2. soma: cell body with nucleus 3. axon: path from soma to the terminal buttons
extracellular fluid • salty bath that surrounds neurons take in oxygen, nutrients and drugs elimate waste
Terminal buttons small buttons next to cell "neighbors" • contain synaptic vesicles: packets of neurotransmitters "water balloons"
What is myelin made out of coiled glial cell layer
Four classes of glial cells 1. schwan cells 2. oligodendrocytes 3. astrocytes 4. microglia
schwan cells (glial cell) insulates peripheral nerves: muscles, organs, glands
oligodendrocytes insulates central nervous system
astrocytes largest glia, star-shaped, many functions
microglia involved in response to injury or disease
nodes/ranvier breaks in insulation to allow access to outside chemicals to replenish signal strength
Saltatory Conduction electricity travels fast then stop to replenish • salta means to leap
Cell body (soma) • metabolic care of neuron • synthesizes proteins • contains chromosomes/genes
Transcription factors turn on appropriate genes to make proteins
Axoplasmic transport new proteins travel where needed inside microtubles which takes them there and back
Resting membrane electrical potential -70mV
polarized carries a charge at rest
Sodium (Na+) • lives outside • pushing inward • 50mV b/c it's less crowded inside • 70mV b/c it's attracted to negative • 120mV inward
Chloride (Cl-) • balanced • 70mV inward b/c it's crowded outside • -70mV inward b/c like repels like
Potassium (K+) • 90mV outward b/c it's crowded inside • repels by positive outside • made inside
Negatively charged proteins (A-) • can't move outside
Factors contributing to even distribution 1. random motion (diffusion) 2. electrostatic pressure
Factors contributing to uneven distribution 1. only certain ions can fit through pores called ion channels (passive, takes no energy) 2. sodium-potassium pumps (active, takes energy)
Sodium-potassium/maintenance pump 3 NA+ out and 2 K+ back in
Threshold for firing -50mV • become less negative: depolarized
3 stimulations that open an ion channel depolarization: closer to threshold, open Na+ channels, excitatory hyperpolarization: further from threshold, open Cl- /K+ channels, inhibitory
What local potentials have in common 1. Graded reaction (loud/insistent vote) 2. rest after stimulation 3. activity decays rapidly 4. summation/integration
local vs action potential 1. grade v all or nothing 2. decremental (diminishes over distance) v non-decremental 3. spatial (frequency) and temporal (multiple neurons) summation v intensity of stimulus coded by rate of firing 4. produced by opening of ligand-gated channels v opening of voltage-gated channels
what are the 3 phases of action potential 1. rising 2. re-polarization 3. hyper-polarization
The steps of action potential 1. Na+ channel opens (-70mV to -50mV) 2. K+ channel opens to slow down depolarization 3. At 1ms Na+ channels close to begin repolarizing 4. K+ doors close late causing hyperpolarization
Absolute Refractory Period impossible to initiate another action potential (1-2ms after)
Relative Refractory Period harder to initiate another action potential (varies, only with extra stimulation)
Refractory Periods • post-action potential • for cell to rest • limits rate of firing • prevents backward movement of AP
Summary 1. neuron membranes have resting potential (charge) 2. incoming signals (ESPS & ISPS) at a neuron's receptor areas can locally change the charge 3. These incoming PSPs are transmitted passively to place at border between axon hillock & axon 4. That area summates/integrates PSPs and decides AP or nah 5. If yes, Na+ channels open and the signal jumps down axon (saltatory conduction) toward terminal buttons
Medial towards the middle
Lateral towards sides
Dorsal • towards back • top of head
posterior • towards feet • back of head
Ventral • towards belly/front • bottom of head
Anterior • toward head/up • front of head/face
Horizontal plane • cut top and bottom in half A _____________ B
Sagittal Plane • cut right and left side of brain | A | B |
Coronal Plane • cut front and back of brain • garage door hitting you
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