epilepsy membrane potentials l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Epilepsy & Membrane Potentials PowerPoint Presentation
Download Presentation
Epilepsy & Membrane Potentials

Loading in 2 Seconds...

play fullscreen
1 / 46

Epilepsy & Membrane Potentials - PowerPoint PPT Presentation


  • 97 Views
  • Uploaded on

Epilepsy & Membrane Potentials. EEG WAVEFORM. Ca 2+. Neural Recording. Excessive Calcium influx leads to a depolarized Resting Membrane. Neurophysiology. Anatomy of the Neuron. Dendrites. Cell Body (organelles). Axon Hillock = Trigger Zone. Direction of Action Potential.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Epilepsy & Membrane Potentials' - trynt


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
epilepsy membrane potentials
Epilepsy & Membrane Potentials

EEG WAVEFORM

Ca2+

Neural Recording

Excessive Calcium influx leads to a depolarized Resting Membrane

slide3

Anatomy of the Neuron

Dendrites

Cell Body

(organelles)

Axon Hillock

= Trigger Zone

Direction of

Action Potential

Axon

Terminals

schwann cells and nodes of ranvier
Schwann cells and Nodes of Ranvier

Schwann cells make MYELIN

MYELIN is an electrical insulator

Action Potential “jump” down myelinated axons by SALTATORY CONDUCTION

action potential propagation along neurons
Action potential propagation along neurons

How does the action potential move from the terminal of neuron 1

to the dendrites of neuron 2?

Direction of

Action Potential

2 main types:

electrical and chemical

SYNAPSE

electrical synapse
Electrical SYNAPSE

Gap Junction

Action potential moves DIRECTLY between neurons

EXAMPLES:

Smooth Muscle

Cardiac Muscle

Gap junction between adjacent cardiac cells

chemical synapse
Chemical SYNAPSE

Presynaptic Terminal

Synaptic CLEFT

Postsynaptic membrane

chemical synapse function
Chemical SYNAPSE: Function

1) Action potential down axon to terminal

2) Ca2+ Channel open; Ca2+ influx

3) Vesicles of Neurotransmitters release into synaptic cleft

- 4)Neurotransmitter diffuse into synaptic cleft

- Bind to LIGAND-gated ion channels

on post-synaptic membrane

chemical synapse signal types on post synaptic membrane
Chemical SYNAPSE: Signal types on post-synaptic membrane
  • EPSP: Excitatory post-synaptic potential

Mechanism

Ligand-gated Na+ channels OPEN

Importance

Increases likelihood of AP in postsynaptic cell

If ENOUGH neurotransmitters are released….AP

local anesthetics novacain lidocaine etc
Local Anesthetics: Novacain, Lidocaine, etc.

Lidocaine

Painful stimulus

Action potential

Sensory Neuron

Blocks LIGAND-gated NA+ channels

NO EPSP……no Action potential on post-synaptic cell……no perception of PAIN

chemical synapse signal types on post synaptic membrane13
Chemical SYNAPSE: Signal types on post-synaptic membrane

2) IPSP: Inhibitory post-synaptic potential

Mechanism

Ligand-gated K+ or CL- channels OPEN on post-synaptic membrane

Importance

Decreases likelihood of AP in postsynaptic cell

presynaptic inhibition and facilitation neuromodulators
Presynaptic INHIBITION and FACILITATION: Neuromodulators

Can modulate the ability of a neuron to release neurotransmitter

Neuron

Collateral Neuron

INHIBITION of neurotransmitter release at

POST-SYNAPTIC membrane

clinically important neurotransmitters neuromodulators
Clinically important neurotransmitters & neuromodulators

Cocaine

Alcohol

Nicotine

Caffeine

Heroin

Viagara

Marijuana

Morphine

Crystal Meth

LSD

Anti-depressants: Prozac

Strychnine

We will cover how some of these drugs work

neural summation
Neural Summation

Spatial

Axon hillock

SUMS EPSP & IPSP

Temporal

Spatial &

Temporal

functional organization of nervous system
Functional Organization of Nervous System

Central Nervous System

Brain & Spinal Cord

Peripheral Nervous System

Spinal Nerves & all other nerves

Motor

Sensory

sensory physiology19
Sensory Physiology
  • Perception of sensation involves

1) External physical signals

2) Converted by physiological process

3) To neural signals (graded & action potentials)

Eye

Light

Phototransduction

Action Potential

in Optic Nerve

1

3

2

general senses
General senses

Perceive touch, pressure, pain, heat, cold, stretch, vibration, changes in position

Located on skinand injoints/muscles

golgi tendon organ tendon stretch receptor
Golgi Tendon Organ: Tendon stretch receptor

Sensory Neurons

Collagen Fibers within Tendon

physiology of cutaneous receptors
Physiology of Cutaneous Receptors
  • Stimulus (Vibration, Pressure, Temperature, Stretch, etc)‏
  • Mechanical and/or biomolecules cause opening/closing of ion channels (K+, Ca2+, Na+) on receptor membrane =

Graded Receptor Potential

3. If receptor membrane depolarizes to threshold =

ACTION POTENTIAL

dorsal column
Dorsal Column

thalamus

Tertiary Neuron

Proprioreception,

Vibration,

Pressure

Secondary Neuron

Primary Neuron

anterolateral system
Anterolateral System

Tertiary Neuron

Touch,

Itch,

Pain,

Temperature

Secondary Neuron

Primary Neuron

blocking pain perception
Blocking Pain Perception

Pressure, Vibration

Pain

Dorsal Column

Anterolateral system

2) Triggered by BRAIN (endorphins)

Heroin & Morphine can trigger

Via Blood

1) Collateral Branch

  • Triggered by Massage, Exercise
  • :

Presynaptic inhibition of 2nd Neuron in Anterolateral System

sensory perception in brain
Sensory Perception in Brain

Somatosensory Cortex (Postcentral Gyrus)

Area on cortex = sensitivity of body part =

# of sensory receptors on that part of body

special senses located in the head region
Special senses (located in the head region)‏
  • Vision
  • Hearing and equilibrium
  • Olfaction
  • Taste

We will ONLY cover Vision as an example of a Special Sense!

eye basic anatomy
Eye: Basic Anatomy

Lens

Pupil

Optic Nerve

Retina

slide33

Retina

Pupil

Lens

Ganglion Cells

Rod & Cones

Bipolar Cells

slide34

Disk

Rhodopsin

slide35

Rhodopsin

Transducin (G-protien)

cGMP-gated Na+/Ca2+ Channel

cGMP

K+ channel

Glutamate

DARK

  • -Rhodopsin: inactive
  • -Transducin: inactive
  • Intracellular cGMP levels HIGH
  • Ion channels are OPEN
  • Membrane potential = -40 mV
  • Glutamate release high onto
  • Bipolar cells!

Bipolar Cells

slide36

Retinal

Activated Transducin (G-protien)

decreases Intracellular cGMP

2

Opsin

Rhodopsin

BLEACHES

cGMP-gated Na+/Ca2+ Channels CLOSE

1

cGMP

3

K+ channel

-40

LIGHT

Photoreceptor

Membrane potential (mV)

5

Glutamate

decreases

-70

4

HYPERPOLARIZATION

Time

Bipolar Cell

6

slide37

Cones: Color & Day Vision

Rod: Night Vision

neural pathway to optic nerve brain
Neural pathway to optic nerve & brain

Optic Nerve

Neural Layer

of Retina

Ganglion Cells

Rod & Cones

Bipolar Cells

neural pathway in brain
Neural Pathway in Brain

Optic Chiasm

Optic Cortex

Optic Nerve

neural processing in brain
Neural Processing in Brain

V4

V3

Layers of signal processing

V2

V1

v1 sends projections dorsal ventral
V1 sends projections Dorsal & Ventral

Dorsal Stream: “Where” & “How” Pathway

Ventral Stream: “What” Pathway

distribution of rod vs cones
Distribution of Rod vs. Cones

# of photoreceptors

Position on Retina

processing visual stimuli
Processing Visual Stimuli

Retinal Processing:

Convergent Neural Network!

1 million ganglion cells!

200:1

Amount of convergence

1:1

125 million photoreceptors!

Position on Retina

neural networks
Neural Networks

Vision

Brain Commands to Muscle

(Motor Output)

circadian rhythms why you get tired when its dark
Circadian Rhythms:Why you get tired when its dark!

Suprachiasmatic Nucleus (SCN)

Melanopsin

Rhodopsin