Ch 13 Flashcards
Neurobiology
study of nervous system
Subdivisions of the nervous system
Central nerbous system and Peripheral nervous system
What does the central nervous system contain
bain and spinal cord
What does the peripheral nervous system contain
Sensory division and motor division
What are the parts of sensory division in the peripheral nervous system
Visceral sensory division and somatic sensory division
what are the parts of motor division in the PNS
Visceral motor division and somatic motor division
What does the visceral motor division do
tells the digestive system what to do
What does the viseral sensory division do
brings info from stomach etc
where does somatic sensory division bring info from
like thigh
what is the subsects of visceral motor division
sympathetic division and parasympathetic division
what does somatic motor division do
moves skeletal muscles. nueromuscular junction
what are the fundamental physiological properties of a neuron?
Excitability (can respond to stimuli), Conductivity (can send signals to distant locations quickly), Secretion (can release chemical messengers)
What does afferent mean
sensory neurons…arising into the central nervous system
What are interneurons
between a sensory and a motor neuron. hot burner
what is efferent
motor neurons…exiting the central nervous system
what is the Neurosoma (soma)
cell body of neuron. where the nucleus is, ER
what is the Neurofibrils of a neuron
Cytoskeletan of network in neuron. important for movement
what is the Nissl bodies
cluster of rough endoplasmic reticulum (protein synthesis). stain darkly
Dendrites
Multibranched processes to detect stimuli. they come from the soma
what is a long nerve fiber that transmits signal to the nexxt cell called
axon
What is the axon collateral
its a branch of the main axon
terminal arborization
branching of the distal end of the neuron. allows the generation of more connections w more neurons
Synaptic knob
swelling at the end of the axon stores and secretes neurotransmitters. communicates w more neurons. they interact w the dendrites of another neuron
what is the purpose of Myelin sheath
Segmented wrapping around the axon. insolates and protects the axon. this helps to speed up the action potential
Node of ranvier
gaps in the myelination. purpose is to allow faster transduction so u can skip along the axon and don’t have to change the voltage
Internode
part of the axon that’s myelinated.
Axon hillock
mound from the soma leading to the axon. The initial segment is the first part of unmyelinated axon
Trigger zone
the axon hillock and initial segment. WHen there’s a big enough ation potential in the soma the trigger zone sends a signnal
What’s it called when a neuron has multiple dendrites on one axon
multipolar
Bipolar
two dendrite projections coming from the cell body
Unipolar
Cell body is projecting off the side of the axon
Anaxonic
multiple dendrites and no axon
What are the supportive cells of the neurons?
Neuroglia (or glia)
Functions of the neuroglia
Protect and help function, bind neurons together to form framework, in fetus, guide migrating neurons to their destinations, if mature neuron is not in synaptic contact it is covered by glial cells. GIVES PRECISION
Oligodendrocytes
Part of a glial cells. They make myelin in brain and spinal cord.
Ependymal cells
glial cell part. Line cavities of brain and spinal cord. they secrete and circulate cerebrospinal fluid. Tall cells! gotta be big
Microglia
phagocytize and destroy microorganisms. eat up the dead nervous tissue.
Astrocytes
part of glial cells that form the blood brain barrior. grab oxygen and glucose and share it w neurons. They don’t let certain things pass the blood brain barrior
Schwann cells
form a neurilemma around all PNS nerve fibers and myelin around most of them. Play a part in neuron regeneration (axon. cell body can’t be fixed)
Satellite cells
surround somas of neurons in the ganglia
Myelin sheath
Insulating layer around nerve fiber. increase the speed of conduction
Myelination
process of producing myelin. starts in fetal development and rapid in infancy. Myelin is 80% lipid so it’s pretty important for them to get enough fat
Unmyelinated nerve fiber
less insolated. Schwann cell wraps around multiple axons so there’s less wrapping per axon
What two factors does signal conduction speed depend on?
presence of myelination, diameter of fiber
If cell body remains intact but nerve fiber is damaged, can it regenerate?
Yes, schwann cells secrete nerve growth factors and they direct regrowth of axon
Can central nervous system (CNS) nerves be regenerated?
no. Think of memory loss
What is a synapses?
Space between axon terminals. Meeting point of a neuron and other cells: nerve tissue, nerve and muscle, glandualar
What is an axodedritic synapse?
axon terminal interacting with postsynaptic dendrite
Axosomatic synapse
Axon terminals directly going to the soma
Axoaxonic synapse
Axon terminal interacting with axon of another cell
Neurotransmitters
messanger molecultes. Can either be excitatory or inhibitory. 5$ movie night
Synaptic knob
part of structure of synapse. contains synaptic vesicles which are packets of neurotransmitters
Synaptic cleft
the gap between neurons. 20-40 nm
Neurotransmitter receptors
they’re on the postsynaptic cell
Electrical synapse
two cells jointed by gap junctions (tiny pours physically connecting two cells). Important in cardiac and smooth muscle where you want everything to happen at once. Very quick transmission. There is no control or decision making of signal (you can’t stop the signal) it just goes.
What does diverging neuron connection look like?
Exponential growth. bigger and bigger
Converging neuron connection
employees tell managers who tell boss. converging together
Reverberating
Positive feedback. loop. axion potential but one axon goes back to the beginning allowing for sustained signaling to occur.
Parallel after-discharge
multiple axon chains on their way to a destination. All of them could send the message or just one or none.
Neurulation in little fetus babies
around week 3 u have neural plate and first trace of CNS. 4 Weeks you have a neural tube cuz the plate folded together. the neural crest (gonna be the spinal cord) is there. all the ingredients are there. U got three encephalons (frebrain, midbrain, and hindbrain). Week 5 you got five secondary vesicles. limb buds. the three brains have more structures in them (there are now five encephalons)
What are some neural tube defects? Spina bifida -
\ vertebrae fail to enclose the spinal cord. Spina bifida occulta is just one or a few vertebrae that don’t fuse properly. Spina bifida cystica is more severe. sac protruding from the spine filled with cerebral spinal fluid
Neural tube defect - microcephaly
small brain. severe mental difficulties. effects forebrain
NTD - anencephaly
no brain formation
