Flashcards in Chapter 45: Hormones and The Endocrine System Deck (20)
What does the endocrine system do? How does it work?
- it's responsible for communication
- works with the nervous system
- specialized cells receive messages and response by decreasing hormones
What is endocrine signaling?
- When endocrine cells secrete hormones that travel long distances in the blood stream
What is paracrine signaling?
- Secreting hormones to neighboring cells (no touchy)
What is autocrine signaling?
When a cell secretes hormones and binds to its own receptors outside of the cell
What is neuroendocrine signaling?
When the axon directly transfer hormones into the blood stream
The endocrine system uses two types of signaling molecules. What are they?
1) Local regulators
- small, nonpolar/hydrophobic
2) Hormone regulators
There are two types of hormone signals, what are they and what makes them different?
1) Water-soluble (philic)
- Starts off in a vesicle
- Released into the blood stream
- Released and attached to receptor protein of target cell
2) Lipid-soluble (phobic)
- Starts off in the cytoplasm
- Released into the blood
- Transport proteins surround it so it doesn't clump up the blood
- Dropped through the membrane into the target cell (no receptors needed)
What are 3 examples of water-soluble hormone signaling?
- G Protein-Coupled Receptors
- Tyrosine Kinase Receptors
- Ion Channel Receptors
Why can the same hormone produce different effects in different target cells?
- the target cells have different receptors
- each target cell has a different structure and function
Two different receptors bind with the same hormone. Why?
They have identical binding sites
What is negative feedback?
A response to a stimulus.
Negative feedback will reduce this stimulus.
What is positive feedback?
Response to a stimulus.
Positive feedback will encourage this stimulus to continue.
What are examples of negative feedback?
- Photosynthesis (Calvin cycle)
- Respiration (Citric Acid Cycle)
What's an example of positive feedback?
How do you turn signaling off in positive feedback?
There needs to be a loss of the original stimulus (baby stops suckling)
What is Homeostasis?
The ability to maintain a constant internal environment even if there's environmental changes.
Hormones help maintain ______.
________ feedback loops are common in maintaining homeostasis.
E.g., just ate, blood glucose is high
1) pancreas secretes insulin
2) insulin encourages transport/storage of glucose
3) blood glucose lowers
What are endocrine disruptors?
Molecules that disrupt hormone signaling (they look similar to molecules in our own bodies and could act like a competitive inhibitor)