Summary
Summary Action potentials and the nervous system
- Course
- Institution
Summary of 7 pages for the course Biology of disease at University of Wolverhampton (Action potentials)
[Show more]
Seller
Follow
rabiahkhan
Content preview
ACTION POTENTIALS AND NEURONALRESPONSES:
Nervous tissues contain two types of cells:
1. Nervous: electrical signalling and communication
2. Glial cells: supporting cells with a range of functions
THE NEURONE:
CELL BODY Metabolic functions
DENDRITES Carry signals to the cell body
AXONS Carry signals away from the cell body
Cell bodies make up the grey matter CNS: nuclei PNS: ganglion
Axons make up the white matter CNS: tract PNS: nerve
Axon hillock is where the axon begins it is where the contents of the neurone begin to differ.
AXON:
There are NO organelles in the axon and the cytoplasm is replaced with the AXOPLASM
- Axons are surrounded by an insulating MYELIN SHEATH which is deposited by GLIAL
CELLS.
Myelin sheath is not continuous but has GAPS along its length called NODES OF RANVIRER
which play a role in movement of electrical impulses across the neurone.
TYPES OF NEURONES:
We class neurones dependent on:
1. Location
2. Function
3. Neurotransmitters (chemical signalling molecules)
4. Shape
- UNIPOLAR (normally sensory)
- BIPOLAR (not common and found in the olfactory epithelium and retina)
- MULTIPOLAR (Most common!)
CELL MEMBRANE
, Ions are polar molecules and as the fatty acid tails are Non-Polar, they repel any
polar/charged molecule.
Therefore, require carrier proteins or channel proteins to allow ions pass through the cell
membrane
LIGAND
GATED CHANNELS
A group of transmembrane ion channels that open or close
in response to the binding of a chemical messenger (ligand)
such as a neurotransmitter.
The neurotransmitter attaches to the receptor causing ions to move in response to the
gradient.
MECHANICALLY GATED CHANNELS
They open because of a physical distortion of the cell membrane.
Many channels associated with the sense of touch (somatosensation)
are mechanically gated.
e.g. pressure applied to skin allows these channels to open and allow
ions to enter the cell.
Other examples are channels opening on the basis of temperature
changes such as in the shower.
VOLTAGE GATED CHANNELS:
Only open due to changes in the electrical properties of the
membrane.
The inner portion of the membrane is at a negative voltage
and when it becomes less negative, the channel begins to
allow ions to cross the membrane
LEAKAGE CHANNELS:
They are randomly gated meaning they open and close at random.
There is no event which opens the channel instead there is an
intrinsic rate of switching between open and closed states.
SODIUM POTASSIUM PUMP:
The sodium/potassium pump in the cell membrane play a major role in regulating ionic
content inside and outside the cell.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller rabiahkhan. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.25. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67474 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now