1. AP Biology Review Systems 1. Homeostasis:
The Endocrine

2. The Endocrine System

3. Local vs Long Distance Signaling
Which type is the endocrine system? Which type is the immune system?

4. Local vs Long Distance Signaling
Local regulators – affect only nearby cells
Paracrine signaling – cells release chemicals to nearby cells
Neurotransmitters released from neurons
Hormones – affect distant cells
Endocrine signaling – chemicals released into blood and carried throughout body

5. Local vs Long Distance Signaling
Cells can also pass messages directly
- Gap junctions
- Plasmodesmata
- “ID tag” recognition

6. Signal Transduction Pathway
What is happening in each step?

7. Signal Transduction Pathway
The steps involved in passing along a message to cause a cellular effect
Signal – something will “land” on the cell surface or go through surface
Transduction – passing/converting the message
Pathway – the steps along the way

8. Signal Transduction Pathway
These pathways are similar among all types of cells, even among very different organisms (including bacteria, yeast, plants, and animals)
What does this tell us about these pathways?
They evolved early
Why would they have been so important that they evolved so early?

9. One chemical signal, different effects
How does the signal know which cell to “talk” to?
Why might there be different effects with different cells?

10. Specificity of Signals
The type of proteins a cell has determine which signals it responds to and how it responds

11. Cell Signal Receptors
What determines whether a signal will bind to a membrane protein or an intracellular protein?
Membrane signals – cannot get through
Large – polar – ionic
Ex: protein hormones
Intracellular signals – can get through
Hydrophobic – small
Ex: lipid hormones (steroids)

12. Types of Chemical Signals: Hormones
Most chemical signals bind to plasma membrane proteins
Signals tend to be __?__molecules
Rate is __?__
Called a “__?__-messenger system”
Transduction
Reception- transduction-response/effect
Protein
– fast
second 12

13. Types of Chemical Signals: Hormones
Most chemical signals bind to plasma membrane proteins
Signals tend to be protein molecules
Rate is faster
Called a “second-messenger system”
Transduction
Reception- transduction-response/effect
Protein
– fast
second 13

14. Cell Signaling: Protein Hormones
Cytoplasm Response
Response may regulate activities
Ex: epinephrine
signals breakdown
of glycogen to
glucose
Notice the signal amplification!

15. Types of Chemical Signals: Hormones
Steroid hormones work differently
Why?
Rate ends up being ___?___
Effect is production of ____?_____
Slower
proteins 15

16. Types of Chemical Signals: Hormones
Steroid hormones work differently
Why? – can enter cell easily
Rate ends up being slower
Effect is production of proteins
Slower
proteins 16

17. Cell Signaling: Lipid Hormones
Nuclear Response
Signal may trigger products to be made
Ex: growth factor signals DNA to make certain proteins needed for growth

18. Negative Feedback
What is the stimulus?
What is the response?

19. Negative Feedback Stimulus & Response in opposite directions
Ex: calcium levels too high in blood… calcitonin causes uptake of calcium from blood

20. The stimulus and response go in the SAME direction.
Positive Feedback
How will stimulus and response relate for this type of feedback?
Do you think this is more or less common than negative feedback? Why?
The stimulus and response go in the SAME direction.
If negative fdbk has stimulus-response in opposite directions, what will positive be?

21. Positive Feedback
Pressure on uterus  oxytocin released causing more pressure…
When does the reaction end?

22. Vertebrate Endocrine System

23. Endocrine Glands/Organs
Pituitary
Growth hormone
Stimulates growth
Oxytocin
Childbirth; lactation
attachment
Tropic hormones
Travel to other glands (ex: TSH, ACTH, FSH)
ADH (Anti-Diuretic Hormone)
Retain water

24. Endocrine Glands/Organs
Thyroid
Thyroxine
Regulates metabolism
Calcitonin
Uptake of Ca in blood

25. Endocrine Glands/Organs
Parathyroid
PTH
Regulates calcium levels (adds Ca to blood)

26. Endocrine Glands/Organs
Adrenal
Epinephrine
Fight-or-flight response
Release of glucose for more ATP

27. Endocrine Glands/Organs
Pancreas
(Pancreatic islets)
Insulin
Removes glucose from blood
Glucagon
Release glucose from glycogen (add to blood)

28. Endocrine Glands/Organs
Testes
Testosterone
Stimulated sperm production
Maintains male sex characteristics