Negative and Positive Feedback (Pages 19-22)

Biologic effect of a hormone

Directly proportional to concentration

Concentration determined by

Rate hormone released

Rate eliminated from body fluids

Peptide (& amines) stored

in endocrine cells

Steroids are - Stored or Not Stored

Not Stored in endocrine cells

Steroids are not stored have to be…..

synthesized

Negative Feedback

Most common control of hormone release

Negative Feedback example

ß-cells of pancreas

ß-cells of pancreas are affected by

blood glucose concentrations

as glucose goes up

release insulin

Muscle (liver & adipose) cells

take up glucose

As glucose taken up, blood glucose concentration ….

Goes down

Glucose/insulin  is….

simple & straight forward

Involve multiple organs

Reproduction (hypothalamus, pituitary, gonad)

Positive feedback is

Less common

Hormone brings….

biologic response

This further increase or decrease release of…

increase, hormone

How is Oxytocin is released?

Released when uterus pushes on the cervix