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Essay 

1. You realize that you have 3 exams and 2 projects 

2. The non specific stress sensory signals occur 

3. This information is received and sent to the brain 

4. The hypothalamus perceives the stress response 

5. Stress stimulates the hypothalamus to release corticotropin releasing hormone 

6. Corticotropin releasing hormone stimulates the anterior pituitary to release adrenocorticotropic hormone 

7. Adrenocorticotropic hormone stimulates adrenal cortex to produce cortisol 

8. Regulates production by negative feedback 

9. The cortisol increases energy that is available in the blood 

10. Increases heart rate, blood pressure, alertness, anxiety, and blood glucose 

11. initiates breakdown of protein and fat for energy 

12. Suppresses immune system which can lead to sickness 

13. Negative feedback loop is initiated to increase cortisol levels on the hypothalamus and pituitary gland. This continues  until the stress signal is gone- tests are taken and projects are done

14. The limbic system is involved for emotion and motivation 

15. Stress is an emotion and you need motivation to study 

16. The insula encodes memory 

17. The cerebrum is responsible for higher mental function 

18. The hippocampus is critical for acquiring new memories 

19. Need slow wave sleep to consolidate long term memory 

20. Long term memory is used to reproduce the information onto the exam 

Phospholipase c-ca2+

• In a resting cell, intracellular Ca²⁺ is low

  • Intracellular Ca²⁺ is pumped from the cytoplasm into endoplasmic reticulum (ER)

• Mechanism of action:

1. Hormone binds to extracellular binding site on the GPCR

2. Causes G protein dissociation

3. G proteins activate phospholipase C in the cell membrane

4. Activated phospholipase C catalyzes breakdown of phosphatidylinositol (PI)

   • Breaks down into inositol triphosphate (IP₃) and diacylglycerol (DAG)

     • Both derivatives can function as 2^nd messengers

5. IP₃ binds to receptors on the ER 

6. Stimulates opening of Ca²⁺ channels

   • Ca²⁺ is released from the ER into the cytoplasm

7. Cytoplasmic Ca²⁺ binds and activates calmodulin

8. Calmodulin (a protein kinase) phosphorylates target proteins

Adenylate cyclase - cAMP

• Mechanism of action:

1. Hormone binds to extracellular site on the G protein-coupled receptor (GPCR)

   • Changes receptor conformational shape

2. G_α dissociates from receptor

3. G_α binds to and activates adenylate cyclase

4. Adenylate cyclase catalyzes ATP into cAMP + PP_i

5. cAMP binds to regulatory subunit of protein kinase

   • Changes conformational shape of the subunit

6. Regulatory subunit dissociates from catalytic subunit

   • Activates catalytic subunit of protein kinase

7. Activated protein kinase phosphorylates target proteins

   • Can cause either protein activation and inactivation to induce desired homeostatic effect

8. cAMP hydrolyzed by phosphodiesterase to turn off signaling

Nuclear receptors 

• Mechanism of action:

1. Carrier proteins transport hormones in blood

2. Hormone dissociates and crosses the plasma membrane

   • Does not require a transporter to cross the membrane

3. Binds to receptor

   • May occur either in cytoplasm and nucleus depending on the hormone

4. Hormone binding induces a conformational change in the receptor 

   • Receptor is now an active transcription factor

5. Receptor binds the hormone response element in the promoter sequence of target genes

6. Transcription is changed

   • May increase or decrease, depending on the hormone and the gene