transmits information from the brain to skeletal muscle 

(control of body movement through skeletal muscle)

communication between the brain, smooth muscles, cardiac muscles and gland cells. 

(involuntary and visceral body functions)

connects the spinal cord with the cerebral region 

-includes the medulla, pons, midbrain

encased in the vertibral column and skull

(i.e. spinal cord, brainstem, cerebellum, cerebral regions)

insulating layer of cells wrapped around the axon 

communicate with the periphery 

-conduct signals between the spinal cord and sympathetic ganglia 

divided into dorsal, lateral and ventral horns 

(looks like an H) 

anterial and lateral dorsal columns 

- glial cells and myelinated axons 

continuous with spinal cord 

contains olives, the pyramid, roots of four cranial nerves 

-axons projecting from the cerebral cortex to the spinal cord.  

superior to the medulla 

-four cranial nerves attach here 

- contains fiber tracts and interspersed nuclei 

anterior forms two cerebral peduncles 

consists of fibers that descend from the cerebral cortex 

four features (two superior and two inferior) in the midbrain 

- responsible for orientation to audio and visual stimuli 

cranial nerves 

(sensory) 

olfactory I

optic II

vestibulocochlear VIII

Cranial Nerves 

(Motor and some Sensory) 

Oculomotor III

Trochlear IV

abducens VI

acessory XI

Hyoglossal XII 

in the cerebellum 

vermis: worm (midline of the cerebellum) 

-function: coordinates movement 

part of the cerebrum 

-includes the

thalamus

hypothalamus

epithalamus (pineal gland)

subthalamus 

maintains metabolic rate and temperature 

regulates eating

reproductive functions

defensive behaviors

expression of emotion 

influences the secretion of other endocrine glands

i.e. pituitary and adrenal 

frontal

parietal

temporal

occipital

limbic (medial aspect)

insular (revealed by separating the temporal and frontal)

plasma that circulates from the brain cavities to the surface of the CNS and reabsorbed into the venous blood system

- provides boyancy to the CNS  and regulates extracellular fluid 

covering of the brain 

layers 

-pia

-arachnoid

-dura 

chemicals that transport signals from one neuron to a target cell across a synapse 

-contained by vesicles in the presynaptic terminal 

allow diffusion of a small number of ions thru the membrane at a slow continuous rate 

opens in response to mechanical forces, tempurature of chemicals 

-sensory neurons

opens in response to a neurotransmitter binding to the surface of a channel receptor on a post synaptic cell membrane 

opens in response to changes in the electric potential across the cell membrane. 

-opens instantly and closes quickly 

-important in releasing neurotransmitters and forming action potential 

neuron is not transmitting information

-no flow of ions across the membrane 

- negative 70mV ( inside of cell is 70mV less negative than the outside of the cell)

later part of action potential 

-returning towards a resting state 

multipule inputs to one cell 

-neural input to sensory integration in the cerebral cortex

single neuron w/many branches

communicates with multiple cells 

Glia: means glue 

- responsible for the shape of the nervous system and trasmit of information.

-may be involved in pathogenesis such as cognative and memory disorders 

big glial cells

star shaped 

-act as scavengers taking up extra K+ 

-cleans up debries in extracellular space

-component of the blood brain barrier 

[image]

forms the myelin sheath 

supports axon 

can wrap around many axons 

[image]

-supporting cell of the PNS

-one swchann cell connects with one segment of the myelin sheath in comparison to oligodendrocytes that wrap around multipul axons 

immune system of the CNS

-function as phagocytes

action potential arrives at presynaptic terminal ---> membrane of postsynaptic cell depolarizes ---> voltage gated Ca2+ channels open 

Calcium influx ---> neurotransmitters are released ----> receptors change shape to either a ionatropic (fast) or metabotropic (slow) 

Na+ or Ca+ flow into postsynaptic neuron and cause depolarization (local potential)

-enough EPSP leads to action potential

(like loading passengeres on a bus, when the bus is full it leaves.)

Neurotransmitter bings to postsynaptic membrane receptor and either CI- or K+ flows out. local hyperpolarization (more negative) of the postsynaptic membrane

-chances of action potential decrease 

axoaxonal communication

- axon 1 releases neurotransmitter and attaches to a second axon slightly depolarizing (less negative) it. 

-influx of Ca2+ into the 2nd axon facilitates the release of more transmitter realease...increases duration of the action potential at the postsynaptic cell

-increases stimulation of postsynaptic neuron 

1 axon releases neurotransmitter that slightly hyperpolarizes the axonal regoin of 2nd neuron. 

-duration of action potential is DECREASED 

-Ca2+ influx is reduced, less neurotransmitter is released into the postsynaptic cell. 

Neuromodulators secreted by a small group of neurons diffuse through large areas of the nervous system, affecting multiple neurons. 

-Slow acting

-usually g-protien receptors 

molecules that relay signals from receptors on the cell surface to target molecules inside the cell, in the cytoplasm or nucleus

g protein recepters are the most abundant in the human genome 

- affects long lasting systems, regulates mood

pain preception, movement, motivation

cognition

-ionatropic (fast)

-excitatory (inhibitory in cardiac muscle)

-PNS and CNS

-motor functions 

-only neurotransmitter in the somatic nervous system 

-principle neurotransmitter in the autonomic ganglia

-most common excitatory 

-only in CNS

-ionotropic and metabotropic (fast and slow)

-amino acid

-most common in general

-learning and development 

most common inhibitory

-ionatropic and metabotropic (fast and slow)

-low levels could cause seizures and unwanted skeletal muscle contractions. 

inhibitory or excitatory 

fight or flight 

g protein mediated 

-attention to sensory information (PTSD patients) 

slow

excitatory and inhibitory

all use the secondary messager system

-mood, motivation, pleasure seeking, reward

-both neurotransmitter and neuromodulator

fast or slow

usually inhibitory 

-mood, pain, arousal 

direct (fast)

indirect(slow)

Cascade of intracellular events (includes activation of gene) 

type of nonassociative learning, decrease in response to a repeated, benign stimulis 

-used to treat tactile defensiveness 

use or activity dependant plasticity

-persistent, long lasting changes. 

with repetition of a task, the number of active regions in the brain is reduced and only necessary regions are active and focused

-requires synthesis of new proteins, growth of new synapses, modification of existing synapses 

-Essential for neural recovery 

convergence of active synapse to silent synapse  

can enhance or inhibit motor learning and memory formation, depending on frequency and experimental protocol used 

part of the severed axon attached to the cell body 

isolated from the cell body.

-dies if it is unable to connect back with the proximal segment 

-this is done through surgery or through by chance being close enough to reconnect 

myelin sheath pulls away from the segment

axon swells and breaks into shorter segments

glial cells come and scavenge/clean the area (inside the myelin sheath) to make room for axonal regrowth. 

occurs when the denervated target  is reinervated by branches of a axon from a neighboring neuron 

[image]

the injured axon sends out side sprouts to a new target 

[image]

 occurs after destruction of presynaptic neuron.

-postsynaptic neuron develops new receptors at the remaining terminals. (sends out signals for new connections) 

occurs after some presynaptic terminals are lost 

-neurotransmitter accumulates in the undamaged terminals

-results in excessive release of neurotransmitter 

in silent synapses only NMDA receptors are present on the postsynaptic membrane

-unmasking occures when AMPA receptors move into the postsynaptic membrane. 

cell death caused by overexcitement of neurons 

-oxygen deprived neurons release large quantities of glutamate, which kills postsynaptic neurons when released in high concentration. 

TMS (positron emission tomography)

PET

fMRI (functional Magnetic resonance imaging) 

How fast does a damaged axon grow back???

(KNOW!!!!!) 

1 millimeter a day 

about an inch a month 

conception to day 14 

-cell division to solid cell

-blastocyte: the outer layer becomes the fetal contribution ;inner cell mass becomes the embryo

-inner cell mass develops into the embryonic disk (three layers) 

day 15-8th week

-organs are formed 

end of 8 weeks to birth 

-nervous system develops more fully 

-myelination begins 

at the embryonic stage and happens in two phases 

-neural tube formation

-brain formation 

day 18-26 

1. neural plate forms (flat)

2. neural groove forms (plate folding together until folds touch)(day 18 - 21)

3.  neural tube and crest forms  

4. neuropores (ends of neural tube) close by day 26 and differenciate into two concentric rings 

ends of the neural tube 

bulges on the surface of the embryo 

sclerotome: become the vertebrae and skull

myotome: becomes the skeletal muscle

dermatome: becomes the dermis 

two meanings 

1. area of somite that will become the dermis 

2. after the embryonic stage, dermis innervated by a singer spinal nerve 

two meanings 

1. part of the somite that will become the skeletal muscle 

2. after the embryonic stage, a group of muscles innervated by a single spinal nerve. 

enlargement process (brain formation)  

1. epithelial cells that line the neural tube divide to produce neurons and glial cells

2. neurons migrate to their final locations 

- function (visual, auditory, motor...) is determined by what area of the brain they migrate to.

3. myelination: begins in the fourth fetal month 

4. growth cone: the moving tip of a growing axon, exploring, contacting other cells and chemical cues 

regressive process that shapes the nervous system 

claims as many as half the neurons formed during the development of the brain regions 

regressive process that shapes the nervous system 

axon retracting from unattractive chemicals 

the times when the neuronal projections are competing for synaptic sites; the nervous system optimizes neural connections during the critical periods. 

ex. monkey eye sutured shut from birth to 6 months -- could not see out of the sutured eye after the sutures were removed 

neural tube defects that result when the inferior neuropore does not close 

-meningolcele: meninges protrude through bony defect 

-meningomyocele: meninges and muscle protrude

-myeloschisis: malformed spinal cord open to the surface of the body  

excessive involuntary muscle contractions, causing stiffness and shortening of the muscle