Class notes
Chapter 14 hormonal communication
- Course
- Institution
notes for biology a level ocr A (hormonal communication)
[Show more]
Seller
Follow
jenishasuresh
Content preview
Endocrine system and hormone types 14.123/01/23
Homeostasis = maintenance of our internal environment relatively stable
through negative feedback e.g. blood glucose levels / body temp / water levels in
blood
→ as learnt in b13 , one way is by nervous system p(detect changes in body
and through electrical impulses to signal other parts of body to stimulate response)
→ ANOTHER way is the endocrine system (release hormones)
Endocrine system
- Contain endocrine glands → secrete hormones into blood plasma that
travel to target cells which have receptors specific to a hormone → can
coordinate a particular response
This is a cell surface membrane with a particular protein + receptor on top. Then
we got the nuclear membrane with pores and DNA on the inside.
2 types of hormones:
1) Peptide hormone
- Peptide hormone e.g. Adrenaline ( released during fight or flight response)
- Peptide hormone means its hydrophilic → so cant go through cell
membrane due to hydrophobic core →so it can instead bind to cell
surface membrane on receptor → this can cause other signals
,- So peptide hormone is the first messenger
- The protein below the receptor is called adenyl cyclase which is an enzyme
( so through the binding of the hormone , it can activate AC which can turn
ATP into Cyclic AMP (cAMP)
- cAMP can then go create an enzyme cascade for reaction (enzyme
cascade refers to a series of diff enzymes being activated one after the
other e.g. cAMP can go to activate protein kinase which is activated to
activate another anyme and keeps going until the actual enzyme they want
to activated to do the reaction they want. an example of a reaction is
turning glycogen → glucose for respiration to occur)
2) Steroid hormone
- e.g. oestrogen
- They are lipid soluble / lipid based
- So they can simply diffuse across membrane → and enter cell
- Here the receptor exists within the cell in the cytoplasm (e.g. steroid
hormone receptor)
- When steroid hormone receptor bind to oestrogen → they can do
various functions → this is a hormone receptor complex
- In the case of oestrogen , they can pass through the nuclear membrane
and become a transcription factor (so they can up/down regulate
transcription of DNA)
, Structure and function of the adrenal gland
- It is found on top of the kidney
(had 2 parts)
Adrenal cortex
- Adrenal cortex (outer layer of gland) mainly gets signalled or controlled by
hormones that are sent from the pg (pg releases hormones to signal the
adrenal cortex to release more hormones) (pg is a master gland as can
produce hormones of its own and produce hormones to have secondary
effects on other endocrine glands)
- Adrenal cortex releases 3 types of steroid hormones (lipid soluble):
1) Glucocorticoids = cortisol regulates glucose + protein metabolism
+ BP. another example of this is corticosterone which regulate
immune response and suppress inflammatory response
2) Mineralocorticoids = maintain salt concentration to control bp
e.g. aldosterone
3) Androgens = sex hormone with little effect
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 jenishasuresh. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.91. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67232 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now