Homeostasis And The Endocrine System Flashcards
What is the HPG axis?
Hypothalamic pituitary gonadal axis
Gonads - testes and ovaries
Begins with gonadotropin releasing hormone
Gonads release sex steroid hormones (test,progesterone, estrogen etc.
Where can steroid hormones be made?
Produced in the gonads,adrenal cortex, and kidneys
What are the original anabolic steroids and what can they do?
Test and dihydrotestosterone (DHT)
-stimulates spermatogenesis and development of secondary sexual characteristics
-Precursor of all estrogens
What similarities does estrogens have to testosterone and what effects do they cause?
Like test, they have anabolic effects
-stimulate ovulation
-with progesterone regulate menstrual cycle
-development of secondary sexual characteristics
Sex hormones are sort of a system from brain to gonads, what is the small process for now of it?
GnRH from hypothalamus (gonadotropin releasing hormone)
-releases LH/FSH from pituitary leading to release of sex hormones from gonads
Why is the pancreas not an endocrine organ?
It has both exocrine and endocrine cells
Acinar cells (exocrine) - secrete digestive enzymes and exocrine function
Islet cells - endocrine function
What is reactive and predictive homeostasis?
Calcitronin-reactive (releases hormones to manage calcium levels)
Insulin - predictive (Consumption of a meal can trigger insulin before blood glucose rise such as taste)
What types of coordinated actions are there in hormones?
-Synergism
-permissivism
-functional antagonism
What is synergism?
Hormones that produce an effect greater than the sum of the effect of each hormone alone
E.g.Glucagon,epinephrine,cortisol
What is permissivism?
-when some hormones can have an effect if only another hormone is present
-If necessary hormone is missing then the effect of other hormones may be reduced or almost absent
What is functional antagonism?
-Hormones that have opposing effects
-Eg. Calcitonin and Parathyroid hormone have opposing effects on blood calcium, each have their own cycle and affect their own receptors
What does the pineal grand secrete?
Melatonin which is derived from seratonin
Production is stimulated by darkness and inhibited by light
