Hormones and the Endocrine System 

Hormones and other signaling molecules bind to larger receptors, triggering specific response pathways 

- HORMONES: chemical signals that cause a response n target cells 

- POSITIVE AND NEGATIVE FEEDBACK: regulates most endocrine secretion 

    - anytime your body is trying to do the opposite of what the body is doing then it is negative feedback 

    - giving birth and breast feeding is positive feedback 

    - negative feedback words: reverses, returns to 

    - positive feedback words: amplifies 

Feedback regulation and coordination with the nervous system are common in endocrine signaling 

- a feedback loop linking the response back to the initial stimulus is characteristic of hormone control pathways 

- NEGATIVE FEEDBACK LOOP: when the response reduces the initial stimulus 

- POSITIVE FEEDBACK LOOP: reinforce a stimulus leading to an even greater response 

- TROPIC HORMONES: ones that affect other endocrine glands

Endocrine glands respond to diverse stimuli in regulating homeostasis, development, and behavior 

- HYPOTHALAMUS: receives information from the nerves throughout the body and from other parts of the brain and then initiates endocrine signals in response  

- POSTERIOR PITUITARY: extension of the hypothalamus that stores and releases these two hormones 

   - OXYTOCIN: causes the contraction of the uterine muscles

    - ANTIDIURETIC HORMONE: makes collecting tubules of the kidney more permeable to water, releasing water retention 

- the anatomy of a nephron includes: boman's capsule, glomerulus, proximal tubule, loop of henle, descending, ascending, distal tubule, collecting duct

- the loop of henle contributes to longer water conservation 

- COUNTERCURRENT MULTIPLIER SYSTEM: counter current system 

   - expends energy to create concentration gradients 

- antidiuretic hormone (ADH) contributes to the regulation of kidney function 

   - made in the hypothalamus

    - target: distal tubule and collecting duct 

    - amplifies water reabsorption 

    - alcohol inhibits ADH

    - produces water loss and dehydration 

- ANTERIOR PITUITARY: consists of endocrine cells that synthesize and secrete several hormones 

- FOLICLE STIMULATING HORMONES: stimulates development of the ovarian follicles in females and promotes spermatogenesis in males by acting on the cells in seminiferous tubules 

- LUTENIZING HORMONE: triggers ovulation of females and stimulates the production of testosterone by the interstadial call of the testes