Cell Bio 2 Review 2

presynapse

neuron sending the signal, origin of the synaptic signal

synaptic vesicles

hold the neurotransmitters before they are released

Glutamine

major excitatory neurotransmitter

GABA

major inhibitory neurotransmitter

AMPA

glutamate receptor

NMDA

GABA receptor

postsynaptic density

area of specialization, contains receptors

proximal

Nearer to the trunk of the body

distal

Farther from the trunk of the body

contralateral

on the opposite side of the body

ipsilateral

on the same side of the body

Affervent nerves

carries sensory information from periphery organs to central nervous system

Effervent nerves

carries motor signal from central nervous system to muscles

long-term potentiation (LTP)

sustained facilitation of the connection between 2 neurons

long-term depression (LTD)

sustained decrease in the electrical connection between 2 neurons

LTP is gated by

voltage and neurotransmitter binding

excitatory postsynaptic potential (EPSP)

a slight depolarization of a postsynaptic cell, bringing the membrane potential of that cell closer to the threshold for an action potential (+ ions in, - ions out)

inhibitory postsynaptic potential (IPSP)

an inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by neurotransmitter release at an inhibitory synapse (+ ions out, - ions in)

neural plasticity

the changing of the structure, function and organization of neurons in response to experiences

3 types of neural plasticity

anatomical changes, metabolic changes, neurochemical changes

Synaptogenesis

the process by which neurons form synapses with other neurons, connections between neurons

synaptic pruning

the elimination of neurons as the result of nonuse or lack of stimulation (increases efficiency of neural network)

neural migration

the movement of neurons from one part of the fetal brain to their more permanent destination along radial glia fibers

Dendrites \___ signals; axons \___ signals

receive, send

synaptic efficacy

the capacity of a presynaptic input to influence postsynaptic output

Hebb's postulate

neurons that fire together wire together

rabbit hippocampal experiment (LTP):

high frequency stimulus results in sustained increase in efficacy of synaptic transmission, singular test shock creates no change

rat hippocampal experiment (LTD):

repetitive low frequency stimulation was synapse specific, saturable, and required activation of NMDA receptors

saturable

there is a limit to how much a signal can be depressed

induction

Stage 1: postsynaptic neuron realizes that a particular input needs to be changed

selectivity

Stage 2: a particular kind of change is selected based on input parameters

expression

Stage 3: the synaptic efficacy is changed

maintenance

Stage 4: the efficacy change is maintained over a long period of time

A major player in the postsynaptic cell is \______

calcium

\__________ leads to Ca2+ entry

neurotransmitter binding

Ca2+ dependent second messengers impact \_________

protein kinases and protein phosphatases

True or False: signals must be coupled
When the presynaptic cell releases neurotransmitters, the glutamate receptors of the postsynaptic cell activate
causes depolarization of the postsynaptic cell membrane

True

Ca2+ increase occurs only \_______

locally

\______ and \________ as well as \________ of the \___________ inhibit longer distances

diffusion, buffering, pinching, spine neck

What happens locally at the postsynaptic density that allows for calcium localization?

complex scaffolding networks of glutamate receptors like NMDA and AMPA

how does the cell determine if the signal is important?

needs to overcome the depolarization threshold, measured in terms of signal propagation (action potential)

time dependence

when signals are fired in rapid succession, the postsynaptic cells are able to add up the responses (increase)

spatial dependence

firing two spines that are close together means that the signals can integrate

\__________ decays with distance, unlike \________

dendrite depolarization, action potential

associativity

an input must be associated with the exiting signal but doesn't need to be a significant contributor

germ lines are

set aside early in development to carry genetic material to the next generation

somatic cells

support physiology and do not contribute to the next generation

\______ cells are the only cells to enter meiosis

germ-line

meiosis generates \______ in the testes and \________ in the ovaries

sperm, eggs

Primordial germ cell migration

germ cells move from temporary "set aside" location to gonads

Primordial germ cell migration requires:

chemotactic gradient of SDF1, aka CXCL-12

primordial germ cell migration in mouse experiment day 9

germ cells motile but still in gut

primordial germ cell migration in mouse experiment day 9.5

germ cells leave gut and migrate to genital ridges

primordial germ cell migration in mouse experiment day 10.5

germ cells form clusters at genital ridges and slow down

primordial germ cell migration in mouse experiment day 11.5

organization of developing gonads

genital ridges

early form of gonads that eventually become ovaries or testes

Chemotaxis

Cell movement that occurs in response to chemical stimulus (germ cell migration)

\________ express CXCR4, the \_______ for \_________ factor \_________

germ cells, receptor, growth, SDF1

\______ express SDF1, the \_______ for \_________

somatic cells, ligand, CXCR4

migrating germ cells follow:

a local gradient of SDF1

SRY (sex-determining region Y) gene expressed only in \_______ in \________ cells within the \__________

males, somatic, genital ridge

SRY gene

sex determining region of the Y chromosome

SRY protein

transcription factor expressed only in somatic cells

oogonia

an immature female reproductive cell that gives rise to primary oocytes by mitosis

polar body

a small cell that is produced with the oocyte and later discarded

primary oocyte is created

before birth

egg coat

complex ECM surrounding egg

cortical granules

vesicles stored just below the egg plasma membrane

mammals produce small \_______ that \______ the embryo until they can \_______ from the \_______

eggs, support, feed, placenta

egg stage 1

oogonium (before birth)

egg stage 2

primary oocyte (before birth)

egg stage 3

secondary oocyte (after birth)

egg stage 4

mature egg (after birth)

egg meiotic divisions are

asymmetric

\________ continuously undergo mitosis

spermatogonia

sperm meiotic divisions are

symmetric

sperm stage 1

spermatogonia (after birth)

sperm stage 2

primary spermatocyte (after birth)

sperm stage 3

secondary spermatocytes (2) (after birth)

sperm stage 4

spermatids (4) (after birth)

sperm stage 5

mature sperm (differentiation) (after birth)

testes

complex branched network of connected seminiferous tubules

sperm are \_____

gametes

cytoplasmic bridges

allow differentiating spermatids access to the full genome needed for sperm differentiation

acrosome

A vesicle at the tip of a sperm cell that helps the sperm penetrate the egg

haploid nucleus

compact DNA using protamine instead of histones

flagellum

specialized cilia powered by dynein to propel sperm

maturing spermatids are connected by \________

cytoplasmic bridges

sperm receptors for:

o-linked oligosaccharides in egg coat

sperm receptor binding triggers:

calcium entry into sperm head

acrosome reaction:

secretes egg binding and fusion proteins (binds sperm membrane to egg membrane)

egg receptors:

recognize sperm and trigger calcium entry into egg

calcium entry in egg:

depolarizes the egg membrane and exocytosis causes egg coat proteins no longer bind sperm

egg depolarization

prevents additional sperm fusion

acrosome exocytosis

releases proteases to cleave ZP2 and hardens the ZP to further sperm entry

Immediately after fertilization the sperm and egg \________ are still \_______

pronucleus, separate

zygote

fertilized egg

ectoderm

skin and nervous system

mesoderm

bones, muscles, circulatory system