Neuro exam 1

levels of causality

relational, necessary, sufficient

levels of analysis

molecular, cellular, systems, behavioral, cognitive

early evidence

hominid skulls have evidence of tool inflicted wounds, shows they knew brain was important

Galen

studied brain by studying its structure

cerebellum was hard to touch so must control hard body parts

cerebrum soft so must control sensations and memories

Rene Descartes

mind brain division. I think therefor I am

mind brain division

pineal gland is only unimpaired midline brain structure (rene thought it was to communicate with spirits)

White matter

mylenated axons

grey matter

neuronal cell bodies

Stimulating nerve and muscle tissue

electrical current could contract muscles, found that electricity controls functions

doctrine of specific nerve energies

all nerves carry the same electrical signal but different nerves carry different information

Ventral root damage

motor paralysis

Dorsal root damage

impaired sensory functions

flourens

provided first evidence of localization of function in the brain

phrenology

bumps on skull signals a map

brocas area

can speak but can understand

found because there was damage to a specific part of the left side of the brain

lateralization

evolution requires

variability, heritability, different survival

natural selection

darwin -how have species evolved

sexual selection

darwin - mate selection often acts against natural selection, female selects mates that have signals of fitness

animal research

researcher must be novel, number of animals must be minimal possible, least amount of pain and distress, principle investigator is qualified, lowest species available is being used, must have nesessary and sufficient levels of causality

why is anatomy important

structure and function relationship

functional anatomy

Nissl stain

stain every cell just see cell body

golgi stain

see the neurites (dendrites and axons)

only taken up by some neurons

cajals contribution

neural circuitry, neurons are discontinuous

neuron doctrine

neurons adhere to cell theory, based on golgi stain but confirmed with electron microscopy

cell theory

individual cells are the basis of an organism, what the organism does depends on what the cells do

synaptic distance

20nm

ratio of neurons to glial cells

1:1

macroglial cells

astrocytes

oligodendrocytes

schwann cells

ependymal cells

astrocytes

nutrition to neurons, seal around synaptic junctions, clean up and fill damaged brain tissue, maintain chemical composition of extracellular fluid outside neurons, communicate btwn neurons and surrounding vasculature

mylenating glia

serve to insulate axonal segments from the surronding extracellular fluid

where do neurons regenerate

peripheral nervous system do, do not in brain or spine

oligodendroglial cells

in the central nervous system -brain and spinal cord

schwann cells

in the peripheral nervous system, promote axonal regeneration

ependymal cells

line the ventricles of the brain and cilia pump cerebral spinal fluid

contribute to axon guidance during developmetn

migroglia

change structure and funtion

serve as phages -clean up dead brain tissue

part of brains immune response

produced in bone marrow

pyramidal cell

basilar and apical dendrites

stellate cell

dendrites in radial pattern

5 types of neuronal classification

number of neurites

dendric arborization

their connections

axon length

gene expression

gene expression

dominant use for classification

after a genetic difference is known between neurons a neon protein can be introduced that can be identified

cell membrane thickness

5nm

cell membrane

boundary of the cell

phospholipid bilayer with both hydrophilic and hydrophobic components

detects chemical signals, detects voltage differences, sometimes allows for passage of ions

hydrophilic head

attracted to water, suspends itself in fluids

hydrophobic tails

float together in continuous thin fatty layer

cytoplasm

fills the space within the cell membranes

includes the cytosol and the organelles

cytosol

rich in potassium ions and has lower concentrations of other ion

nucleus

command and control center

every cell has all the genes it matters how the genes are expressed to determine funtcion

STEM cells

cells early in development that can differentiate into any type of cell

different cell types have different transcription factors

length of DNA uncoiled

2 meters

gene expression

goal of gene expression is to build proteins in the cell

what is a protien

sequence of amino acids (20 make up all protiens)

How do you get amino acids

9 come from diet the rest can be made by the body

triplet

a sequence of 3 nucleotides in the DNA defines the amino acid

protein synthesis steps

replication, DNA, transcription (rna synthesis) mRNA, cytoplasm, ribosome, rough ER, translation, protein

transcription

DNA to mRNA

translation

mRNA to protein (happens in 2-3hrs)

DNA central dogma

DNA is the molecule of hereditary, DNA codes for mRNA, mRNA codes for proteins

nuclear pores

allow for transport of specialized elements into and out of the nucleus

gene

a sequence of nucleotides that encode for a specific protien

exons

sections of rna that are code for proteins

introns

noncoding regions of RNA

splice variants

occur when different exons are removed with the introns

promoter region

transcription initiation

terminator region

transcription stops

Three bases on mRNA

codon

three bases on +RNA

anti-codon (matching nucleotide sequence that transports the mRNA to a ribosome

free floating ribosomes

produce proteins for use in the cytoplasm (allows for synaptic plasticity)

polyribosomes

multiple copies of same segment of mRNA

Rough ER

covered with ribosomes to make protiens

smooth er

produces lipid molecules and keeps calcium (high levels can kill the cell)

golgi apparatus

edits proteins and packages them into vesicles to prepare them for transport

mitochondria

site of cellular respiration, generates ATP, have own mitochondrial DNA

cytoskeleton

internal scaffolding of neuronal membrane, (bones of neuron), vesicles transported via microtubules and microfilaments

three bones of neuron

microtubules (20nm), microfilaments (10nm), neurofilaments (5nm)

microtubule associate proteins

anchor microtubules together, (TAU, a map, accumulates in the cell body causing neurofibrillary tangles, kills the cell =alzheimers)

axon parts

axon hillock, axon proper, axon terminal

axon hillock

initial segment

axon proper

middle

axon vs soma

no rough er or free ribosomes, unique protein and chemical composition, creates need for ventricles

axon terminal

no microtubules, has synaptic vesicles, lots of membrane bound proteins, large number of mitochondria (uses lots of energy)

kinesin

anterograde transport -cell body to terminal (away from cell center)

dynein

retrograde transport -terminal to cell body

synapse connections

axo-somatic, axo-dendric, axo-axonic

ion

atom or molecule carrying an electrical charge (cation or anion)

anion

negative charge

cation

positive charge

ion channels

proteins that allow free passage of specific ions into and out of the neuron

leak

ion channels always open

gated

ion channels voltage, chemical, both, or some other stimulus to open

ion transporters

proteins that maintain the normal distribution of ions inside and outside the cell

peptide

chain of amino acids

protein structure primary

AA sequence and amino groups with variable R group

protein structure secondary

alpha helix

protein structure tertiary

3D folding of polypeptide

protein structure quartenrnary

different subunits that make up the channel protein

Na+/K+ transporter

move against concentration gradient, energy dependent process, ion concentration differences are how cells store electrical charge,

ratio of potassium inside the cell to outside

20:1

electrical potentials

create electrical gradients allowing for the possibility of allowing ions to flow in a preffered direction

membrane potential of a neuron

rests at -70mV

diffusion

similar ions don’t like to be together and if able to move they will go down a concentration gradient until they achieve equilibrium

electrostatic pressure

draw to regions that are oppositely charged