Neurobio Module 1

What are the 2 major divisions of the Nervous System?

CNS and PNS

Where is CNS located and what is its function?

brain and spinal cord/ somatic Motor

Where is the PNS located and what does it do?

Everywhere except the CNS and it is sensory.

3 Major Functions of Neurons

Detection of stimuli, Association (decision making and memories), Commands CNS (somatic and Motor)

Afferent and Efferent Neurons

Afferent— from PNS to CNS

Efferent- from CNS to PNS to Peripheral Targets

What are the two types of Efferent Neurons

somatic and autonomic

Two Parts for the Autonomic Efferent Neuron pathway

Pre ganglionic (CNS to PNS) and

Post Ganglionic (PNS to Peripheral Targets)

Hindbrain/Brain stem

medulla, pons, cerebellum; Basic Biological Functions from survival

Medulla

Involuntary movements (breathing)

Pons

Helps medulla and dreaming

Cerebellum

Movement and balance

reticular formation

Brainstem/ sleep regulation and emotional modulation

mid brain

Hearing vision and Motor Modulation

Consists of: tectum (roof), Tegmentum (floor)

Tectum

superior and inferior colliculi/ hearing and vision

Tegmentum

substantia nigra, VTA, PAG

Substantia nigra- Voluntary movement

VTA and PGA- Emotional Behavior expression

Forebrain

Largest; contains Cerebrum, Thalamus, Hypothalamus

Cerebrum

Thinking center

Thalamus

Learning/Decision making

Hypothalamus

Emotional behavior/ homeostasis

Where are the Cell bodies of Spinal Cord Located

Grey Matter

Where are the axons of the spinal cord located

White matter

Which side do Afferent Neurons enter the Spine

Dorsal Side

Where do Efferent Neurons leave the Spine.

Ventral Side

dorsal root ganglion

Bulge in dorsal Spine nerves, contain cell bodies of peripheral sensory Neurons.

Longitudinal Organization of the Spine

Top (Rostral)

Cervical (back of head, neck, diaphragm, arms hands)

Thoracic (chest/Abdomen)

Lumbar (Legs/feet/back)

Sacral (bowl/bladder movements)

Coccygeal

Bottom (caudal)

3 main nerves in Spinal Bundle

Sensory, motor, autonomic

What are Dermatomes and Myotomes?

Skin and muscle are innervated by 1 Neuron

What nerves Innervate the left, right, top, and bottom of body respectively.

Left innervates left, right innervates right and vice versa

Two Major Components of PNS

Sensory Neurons and Postganglionic Neurons

Jobs of Sensory Neurons

Sensation (light, sound, chemicals, somatosensory aka touch, temp, proprioception aka body movement/orientation, Pain)

Cranial Nerves

Transporting signals from sensory organs to CNS (head to brain only), 12 sets of nerves.

Types of Cranial Nerves

Visual, Auditory, Vestibular (balance), Olfactory (smell), Gustatory (taste)

Spinal Nerves

31 pairs, transfer somatosensory stimuli to CNS

Spinal Nerve nerve bodies are located Where?

Root ganglion

Cervical Enlargement and Lumbar Enlargement

two enlargements of the spinal cord because of large number of nerves innervating arms, hands, legs, and feet

cauda equina

At the end of Spinal cord and has no Neuronal Cell bodies

autonomic nervous system is responsible for_______.

Involuntary movement, can also be inhibitory

Two parts of Autonomic Nervous system

sympathetic and parasympathetic

Which Neurotransmitter does parasympathetic primarily use

Acetylcholine

Neurotransmitters used by Sypathetic

Acetylcholine(Preganglionic) and Norepinephrine (Postganglionic)

Parasympathetic has _____ preganglion and _____ post whereas Sympathetics has _____ preganglion and ______ post.

Long,short and Short,Long

For Parasympathetic. Where do pre and Postganglionic nerves originate from

Pre: Brainstem of sacral region

Post: near target organ

For sympathetic. Where do pre and Postganglionic nerves originate from

Pre: Thoracic and Lumbar Spinal regions of spine

Post: Sympathetic ganglion chain near spinal cord

What is contained in Grey Matter

Neuronal Cell Bodies, glial Cells, Unmyelinated dendrites and axons

White matter contains.....

Myelinated axon tracts (myelin sheaths give white color from fat)

Fluid filled cavity in middle of brain and spine is called

Ventricle in brain and Central canal in Spine

What is Dorsal Horn

Grey matter on dorsal side of spinal cord that send sensory information to brain (afferent)

What is Ventral Horn

Grey matter on Ventral side of spinal cord, has motor neurons

The Brain has 4 interconnected Ventricle chambers, What are they.

2 lateral, 3rd ventricle and 4th that becomes the central canal for Spinal Cord.

Spine tap is done between L3 and 4 or lumbar spinal region because there are......

No Neuronal cell bodies after L2 region

What produces CSF

Choroid plexus (lines walls of ventricles)

CSF deposits waste to blood in the _________

Subarachnoid space

CSF is used to diagnose_________

Brain Infections

What is hydrocephalus? And what are the two types.

Disruption of CSF, Either non-communicating which is blockage between ventricles or communicating which is either increased productions or decreased reabsorption.

2 Types of Protein trafficking Pathways

Non-vesicular and Vesicular

Describe Non-Vesicular trafficking

No vesicles, proteins made at excretion site, moved by cytoplasmic adaptors and carrier protein, proteins also have a localization sequence that determines where they go

Describe vesicular trafficking pathway

Made proteins brought to ER by ER localization sequence. Secretion from ER to Golgi to lysosome then plasma membrane. No targeting sequence= secretion.

3 classes of Neurodegenerative disease

Missing protein, Mislocalized Protein, abnormal export

4 types of Glial cells in CNS

astrocytes, oligodendrocytes, microglia, ependymal cells

Astrocytes Function

Support Neuros/ clear up cleft, provide lactase for energy

Oligodendrocytes function

Myelinate long axons

Ependymal Cells function

Blood brain barrier/ filter blood

Microglia fucntion

Defend CNS from pathogens

2 types for glial cells in PNS

Satellite and Schwann

Satellite cell Fucntion

Clear up cleft, support survival, provide lactase for energy

Schwann cell function

myelinate axons in the PNS

What is Gliopathy and how does it relate to chronic pain conditions?

Dysfunction glia response. In Pain conditions microglia sensitize neuron and Astrocytes don't take up extra glutamate.

Reticular theory of Neuronal Networking

Neurons in the brain form a single continuous network

Neuron Doctrine

the nervous system is made up of discrete individual cells

neural curcuits

group of neurons communicate in specific order to execute task (Afferent, inter and Efferent neurons)

In muscle relaxation Interneurons.....

are used to inhibit neurons.

What is the typical membrane potential of resting neuron and what are the concentrations of K and NA

-70Mv and there is more K in cell and more Na outside of cell

3 Major types of Ion Channels

Voltage gated, Chemical Gated (ligand and ionotrophic), Mechanical gated

resting memebrane potential is upheld by what 3 events

Na/K pump, K leaves through K leak channels, and Na comes in through leak channels

GABA is a __________ Neurotransmitter

inhibitory

What is Process of a Neuron Firing

1. Small influx of NA from stimuli

2. Voltage gated Na channels and cause depolarization to action potential

3. Voltage gated NA channels closes and Voltage gated K channel opens and cause hyperpolarization

4. Na/K pump restores gradients

What are the two types of Synapses?

Chemical and Electrical

What are the mechanisms of transmission in Chemical Synapses

Peptides and Chemical

What type of Secretion is used for peptide Neurotransmitters and where do they communicate with

Constitutive and regulated Secretion of Large Dense core vesicles; far away cells and post synaptic targets

What type of Secretion is used for Chemical Neurotransmitters and where do they interact with.

Regulated secretion of synaptic vesicles, post synaptic targets

Where are peptides and chemical Neurotransmitters synthesized respectively.

Neuron cell body and synaptic terminal

Two types of Electrical Synapses

Ephaptic and Gap Junction

Ephaptic Mechanism

Communication through electric Fields

Gap Junction Mechanism

Communication via bi directional ion flow

3 Major Cytoskeletons

Microtubles, Neurofilaments, Actin Filaments

Microtubles characteristics

Largest diameter, sturdiest and Dynamic/ found middle of cell body, axons, dendrites (no synaptic terminal)

Neurofilaments

Medium diameter, most stable (not dynamic)/ found in Axon

actin filaments

Smallest, most flexible/ found near all plasma memebrane

Long distance transport of proteins involve....

Microtubules and motors called (Kinesins and dyneins)

Functions of Kinesins and Dyneins

Kinesins- anterograde transprort (new proteins to synaptic terminal)

Dyneins- retrograde transports (old proteins to cell body)

constitutive Secretion

Sets up presynaptic terminal; default pathway; delivers peptide neurotransmitters and growth factors for secretion

Regulated Secretion

Presynaptic terminal, actin filaments tether synaptic vesicles and Ca2+ influx releases them

Axon Hillock is rich in...

voltage gated Na Channel

absolute refractory period

time during which another action potential is impossible

relative refractory period

the period of time following an action potential, when it is possible, but difficult, for the neuron to fire a second action potential

What is the Active Zone

Section of plasma membrane in presynaptic terminal where synaptic vesicle fusion happens because Ca Influx

large dense-core vesicle fusion (peptides) fuse at the ......

Peri-active zone

Some synaptic vesicles are docked by _________ proteins

SNARE

Synaptic vesicles are recycles by binding with__________

Endosomes

peptide neurotransmitters are degraded by extracellular ___________

Proteases