100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Previously searched by you
Previously searched by you
logo
The Biochemistry and Physiology of Photoreceptors £7.49   Add to cart
Quickly navigate to
Preview
  2.  
  3. University Of Surrey (UNIS)
  4.  
  5. Integration Of Physiological Systems (BMS2038)

Lecture notes

The Biochemistry and Physiology of Photoreceptors

 10 views  0 purchase

An introduction to photoreceptors located in the eye. Includes information about the cell types, molecules and receptors involved in photoreception.

Preview 1 out of 3  pages

Document information

  • June 26, 2023
  • 3
  • 2020/2021
  • Lecture notes
  • Dr sarah bailey
  • All classes

Subjects

Written for

All documents for this subject (16)

Seller

avatar-seller
kathrynray

Content preview

Photoreceptors Biochemistry and Physiology




• Each type of photoreceptor contains a specific photopigment (visual pigments) - rhodopsin (rods) or red/green/blue
cone pigments (in humans)
• A photopigment contains of an apoprotein, an opsin, which is bound to a prosthetic group, 11-cis-retinal




• The actual photosensitive molecule (chromophore) in vision
• Used in all groups of sighted animals
• Derivative of vitamin A
• A lipophilic molecule consisting of a ring with a long aliphatic tail with conjugated double bonds
• Covalently bound to the opsin protein and buried within a pocket in its lipophilic interior




• Illumination photoisomerises 11-cis-retinal into all-trans-retinal
• Dissociates from the opsin protein
• Radical change in conformation in the opsin molecule
• Activates the phototransduction cascade within the photoreceptor




• The phototransduction rhodopsin molecule activates the G-protein transducin
• Transducin in turn activates cGMP-phosphodiesterase, which breaks down cyclic GMP (cGMP)
• When cGMP levels have gone down to a critical level, cGMP-sensitive ion channels close, leading to hyperpolarisation
of the photoreceptor membrane




• A normal receptor, or any other nerve cells, responds to stimulation by depolarisation
• However, an activated photoreceptor cell hyperpolarises, leading to a decreased release of neurotransmitter
(glutamate)
• Another way to view this is that darkness, rather than light, is the actual stimulus
Integration of Physiological Systems Page 1

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

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

Quick and easy check-out

You can quickly pay through credit card for the summaries. There is no membership needed.

Focus on what matters

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 kathrynray. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for £7.49. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

67866 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now

Start selling
£7.49
  • (0)
  Add to cart