Neuro - exam 1

Anatomical Personology

Anatomical Personology

Gall - first movement of neuroscience - the brain means something

phrenology - bumps tell basic things about personality

Aggregate field

Flourens - brain was not localized - hit your head the whole organ gets damaged

Lashley- complex learning is generalized - small parts of the brain might be involved in smaller things - but thinking and comprehension needs the whole brain

Cellular connectionism

Broca’s- elementary operations of our brain is localized

Jackson- when having a seizure - the seizure shows across certain order of brain - brain parts of the brain is responsible for different movements

Penfield- electrical shocks to different areas of the brain and mapped the brain

Modern Neuroscience

Golgi- exposing brain tissue to silver to show neurons are not connected

Cajal- learned each neuron is off or on

Psychophysical monism

mind and body are one

Modern Neuroscience

Neuron doctrine - basic unit of function in the nervous system is the neuron

Golgi - created silver impregnation method - shows neurons are not connected

Cajal

Jacksons hierarchy of CNS

Spinal cord- reacts to stimulation, provides movement

Myelencephalon

Metencephalon

Mesencephalon

Diencephalon

Telencephalon

Myelencephalon

medulla- basic life functions. breathing, bp, heart rate

Metencephalon

pons and cerebellum - basic motor and posture control

Mesencephalon

peduncles, colliculi (mid brain) - basic sensory motor functions - vision, auditory

Diencephalon

hypothalamus and thalamus - homeostasis, relay station for motor and sensory

Telencephalon

cerebral hemispheres - higher processing functions

Receptive zone

cell integrates signals from other neurons, sums up signal and sends a message

dendrites - focuses messages

Metabolic zone

soma(heart of the cell) - energy is built - neurotransmitter starts to get built

Conductive zone

Axon -myelinated - charge stays and renews every time it jump - not insulated

Transmission zone

terminal Boutons - neurotransmitter is released to communicate w dendrites of next neuron

Parallel Processing

several things all approximate same outcome

EX: stimulate M1 can make you make a fist, secondary M2 can also make you make a fist, red nucleus can also make you make a fist

good for brain damage - other areas can give function

Distributed processing

parts of brain are more efficient at accomplishing specific things

brain puts things in buckets of similarity - does not waste the energy of going into detail -

in order to learn you have to break bucket pattern and create new pathways

Convergence

one neuron or group of neuron can affect lots of neurons

EX: getting sticked w a needle in one neuron - ouch - move hand and affects multiple neurons

EX2:

Neuroplasticity

new neurons can be grown and can change function to do jobs needed

Neurons function

process information, sense environmental changes, communicate changes to other neurons, command body response

Silver impregnation

expose brain tissue to silver, 1% of nitrate takes the stain - shows neurons are not connected

Unipolar neuron

most simple type - one process - operate quickly, on or off

dendrite attached to the axon - attached to cell body

Pseudounipolar neuron

in the dorsal roots of spine - sensory - 2 processes

cell body - spingle process comes off and splits into dendrites and axon

Bipolar neuron

retina is full - 2 processes

cell body - dendrites on top and axon on bottom

Multipolar cells

lots of dendrites - cell body and axon

Soma function

cell body of a neuron

Cytosol: watery fluid in cell

Cytoplasm: contents within a cell membrane

Protein synthesis on free ribosomes

free ribosome wraps around mRNA - translate it into a protein - releases the protein - and goes into ER

mRNA goes to the ribosomes on the rough ER - attach, release a protein, and goes into a membrane associated protein

Cytoskeleton

gives shape and stability - changes depending on function of neuron and how active

Microtubules, Microfilaments (actin), Neurofilaments

Alzheimers

cytoskeleton goes bad and membrane proteins dont work properly - neurons disconnect from each other and die

Plaques form when membrane proteins in the neurons cell membrane are processed differently

Tangles separate from the microtubules causing them to fall apart - destroying the cell neuron

Parts of axon

Axon hillock - beginning - originates the axon

Axon proper - middle

Axon terminal buton - end

Axoplasmic tensport

Anterograde - soma to terminal - Kinesin

Retrograde - terminal to soma - Dyenin protein

Dendrites

Increase surface area for more synapse

brings in info from other neurons

Glia function

form myelin, phagocytosis, supports neuronal functions

Astrocytes- hold together the neurons, sucks up K when too high

Oligodendroglia vs Schwann cells

Oligodendrocytes- CNS - wraps around axons and might affect 5 or 6 axons

jobs is too insulate

Schwann- PNS - only innervates one section of axon

Myelination

insulated - fast

Ions

in watery fluid

Cations- positive

Anions- negative

Sodium chloride

salt dissoves in water because polarity ?

Phospholipid membrane

Doesn’t allow ions to move freely

Heads are polar (hydrophilic)

Tails are nonpolar (hydrophobic)

Sodium- Potassium pump

uses ATP - against gradient - repolarization

3 Na kicked out and 2 K pulled back in

Ion pumps

membrane spanning proteins

shape shows what type of pump - all different shapes and functions

Na pump is for only Na!

Passive transport

down concentration gradients - no ATP

Diffusion- gate opens and ions distribute evenly

Active transpot

Sodium Potassium pump - uses ATP - against concentration gradient

Electrical gradients

negative charges are drawn to positive side

positive charges are drawn to negative side

Resting potential

average -60 to -80

range -40 to -90

Cocaine

neurons fire quicker - hyperactive

messes with membrane permeability

can cause dopamine to not produce it anymore. cant feel good in recovery

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive (voltage gated sodium channels open)

Overshoot

the part of the action potential where the inside of the neuron is positively charged with respect to the outside (peak)

Repolarization

(falling phase) Return of the cell to resting state, caused by reentry of potassium (2) into the cell while sodium (3) exits the cell.

Hyperpolarization

(undershoot) The movement of the membrane potential of a cell away from rest potential in a more negative direction.

stops neuron from firing again

Threshold

enough positive charge for the neuron to fire

the level of stimulation required to trigger a neural impulse
"all-or-nothing"

Rising Phase

inward sodium current
sodium dumps in and potassium leaks out of the cell (slowly) so cell depolarizes

Falling phase

outward potassium current
potassium continues to slowly leak out but spends ATP to begin sodium potassium pump (kicks out 3 sodium and brings in 2 potassium) decreasing net charge
potassium NEVER closes(always leaking out)

Action Potential sizes

can not be bigger or smaller

inject a current into a neuron - lowers the threshold so it can be fired

ATP

adenosine triphosphate

voltage gate

open or close based on polarity, pores are selective to only let in one type of ion

more positive on the outside= positivity pushes the gates down and close the door

more negative on outside= pushes gates up and opens pore= Na rushes in and depolarization

Absolute refractory period

Hyperpolarization - bottom of AP

no AP can be triggered!

Tetrodotoxin from puffer fish

stops AP from happening by blocking Na channels

can be used for chronic pain

Epilepsy

neurons explode and send electricity across the brain causing a seizure

uncontrolled AP going across the brain

K channels

delayed rectifier - slower than Na - more repolarization because open after the peak

both open in response to depolarization

AP traveling

one direction - soma to terminal button

Factors about signal speed

axonal diameter bigger = faster

more myelinated = faster

Presynaptic neuron

tries to influence postsynaptic

Postsynaptic neuron

recieves info from presynaptic and decides to fire or not

Gap junction

electrical synapse

FAST! direct ion transmission from cell to cell - close proximity

Axodendritic

axon to dendrite

Axosomatic

axon to cell body

Axoaxonic

axon to axon

Dendrodendritic

dendrite to dendrite

Neuromuscular junction

fresh muscle tissue and acetylcholine is released- then binds to nicotinic receptors- Na enters the cell- AP generated and the muscle contracts

Amino acid

type of neurotransmitter - Glutamate, glycine, GABA

Amines

type of neurotransmitter - dopamine, acetylcholine, histamine

Peptides

type of neurotransmitter - dynorphin, enkephalins

neurotransmitter synthesis and storage

proteins from golgi travel down to the buton w a secretory granules - precursor molecule (enzyme) - attaches to transporter protein and into synaptic vesicle = mature neurotransmitter

synaptic vesicle holds neurotransmitter until released

Neurotransmitter release

Exocytosis - stimulated by release of intracellular Ca2+ - synaptic vesicle releases

Calcium connects presynaptic membrane and synaptic vesicle

AP happens= Ca2+ comes in presynaptic neuron

recovered by endocytosis (reuptake) - sucks leftover neurotransmitter into synaptic vesicle

G-protein

slower but more graded transmission

activates an enzyme that releases a secondary messenger

EPSP

raises polarity - depolarization (brings closer to 0)

makes post-synaptic neuron more likely to fire

IPSP

hyperpolarization - more negative - makes neuron harder to fire

Excitable dendrites

very small EPSP or IPSP

can increase or decrease the chance of a neuron firing

voltage gated - sodium, calcium, and potassium channels

Shunting inhibition

kill current flow from soma to axon hillock

Autism- lower production of inhibitory cells - systems are firing all the time

Modulation

many signals at all times on neuron - depends on if it fires or not

G proteins can open or close different ion channels

Neurotransmitter recovery

diffusion- away from the synapse

reupate- neurotransmitter re-enters presynaptic axon temrinal

Node of Ranvier

only part of axon that has mitochondria in it -

insulated neuron - node jumps from node - fast and does not slow down

Axon

Antagonists

inhibit/block neurotransmitter receptors

Agonists

mimic neurotransmitter and excite a post-synaptic neuron

look like neurotransmitter

Nicotine is a stimulant

Spatial summation

lots of presynaptic neurons fire at the same time

larger EPSP - raises it closer to threshold

temporal summation

Presynaptic neuron is going to fire on a dendrite many times quickly - postsynaptic neuron never has a chance to reestablish membrane potential