ch 11 endocrine part 2 polar hormones
Studied by 0 people
Call with Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/37
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai |
|---|
No study sessions yet.
38 Terms
Why do polar hormones need second messengers?
Polar hormones cannot cross the plasma membrane, so they bind surface receptors and signal via second messengers.
Where are receptors for polar hormones located?
On the cell surface
Adenylyl Cyclase (cAMP) System
Which hormones use the adenylyl cyclase system?
Epinephrine and norepinephrine when binding beta-adrenergic receptors.
Adenylyl Cyclase (cAMP) System
What happens when epinephrine or norepinephrine binds a beta-adrenergic receptor?
The associated G protein dissociates, and the alpha subunit activates adenylyl cyclase.
Adenylyl Cyclase (cAMP) System
What does adenylyl cyclase do?
Converts ATP into cyclic AMP (cAMP).
Adenylyl Cyclase (cAMP) System
What is the second messenger in the adenylyl cyclase system?
Cyclic AMP (cAMP).
Adenylyl Cyclase (cAMP) System
What does cAMP activate inside the cell?
Protein kinase.
Adenylyl Cyclase (cAMP) System
What do protein kinases do?
Phosphorylate proteins, activating or inactivating enzymes.
Adenylyl Cyclase (cAMP) System
What is the result of the adenylyl cyclase signaling cascade?
Altered cellular metabolism and an appropriate cellular response.
Adenylyl Cyclase (cAMP) System
How is the cAMP signal turned off?
Cyclic AMP phosphodiesterase converts cAMP into AMP.
Phospholipase C System
Which hormone activates the phospholipase system?
Epinephrine only → binds to a adrenergic receptors
Phospholipase C System
What type of receptor activates the phospholipase system?
Alpha-adrenergic receptor.
Phospholipase C System
Why doesn't norepinephrine use the phospholipase system?
Norepinephrine binds only beta-adrenergic receptors.
Phospholipase C System
What enzyme is activated when epinephrine binds an alpha-adrenergic receptor?
Phospholipase C.
Phospholipase C System
What does phospholipase C cleave?
PIP₂ (phosphatidylinositol 4,5-bisphosphate).
Phospholipase C System
What are the products of PIP₂ cleavage?
IP₃ and DAG.
Phospholipase C System
What happens to DAG?
Remains in the membrane.
Phospholipase C System
What happens to IP₃?
Moves into the cytosol and opens calcium channels on the endoplasmic reticulum.
Phospholipase C System
What is the second messenger in the phospholipase system?
Calcium (Ca²⁺).
Phospholipase C System
What happens when calcium is released into the cytosol?
Calcium binds calmodulin.
Phospholipase C System
What does the calcium-calmodulin complex do?
Activates protein kinases and initiates a signaling cascade.
Phospholipase C System
What is the final effect of the phospholipase system?
Altered cellular metabolism.
Tyrosine Kinase System
Which hormones use tyrosine kinase receptors?
Growth factors and insulin.
Tyrosine Kinase System
Why are these receptors called tyrosine kinase receptors?
The receptor itself has enzymatic tyrosine kinase activity.
Tyrosine Kinase System
What two domains do TKRs have?
An extracellular ligand-binding domain and an intracellular enzymatic domain.
Tyrosine Kinase System
What is the key feature of TKRs before ligand binding?
They are separate and inactive (not dimerized).
Tyrosine Kinase System
What happens when a growth factor binds its TKR?
The receptors dimerize, become activated
Tyrosine Kinase System
What happens after TKR dimerization?
Autophosphorylation occurs.
Tyrosine Kinase System
What does autophosphorylation mean?
The receptors phosphorylate themselves and each other.
Tyrosine Kinase System
What happens after TKRs are activated?
They phosphorylate other cellular proteins, starting a signaling cascade = cell metabolism altered.
Tyrosine Kinase System
What is the physiological outcome of growth factor signaling?
Increased cell size, body size, or muscle mass.
Tyrosine Kinase System Insulin
What is the major difference between insulin TKRs and growth factor TKRs?
Insulin receptors are already dimerized before ligand binding.
Tyrosine Kinase System Insulin
Why are insulin TKRs inactive before insulin binds?
They are dimerized but not phosphorylated.
Tyrosine Kinase System Insulin
What happens when insulin binds its receptor?
Autophosphorylation activates the receptor.
Tyrosine Kinase System Insulin
What occurs after insulin receptor activation?
A signaling cascade that alters cellular metabolism.
Tyrosine Kinase System Insulin
What is the primary outcome of insulin signaling?
Increased glucose uptake and anabolic reactions.
List the six mechanisms covered in Chapter 11.
Lipophoilic/non polar:
General lipophilic hormone mechanism, thyroid hormone mechanism (T3 + T4)
Polar hormones/ receptors outside the cell:
adenylyl cyclase, phospholipase C, classical TKR (growth factors), insulin TKR.
What content will NOT be on the exam?
Hormone-specific slides after the TKR mechanisms.
Note 
Flashcards (86)