Exam 2: Endocrinology Flashcards
Berthold’s experiment
Transplantation of a rooster’s testicles into the abdomen resulted in normal development. This told them the testes were not dependent on direct nervous innervation for their activity.
What two body systems control the reproductive system
Nervous & endocrine
Neural reflex
Employs nerves that release neurotransmitters
(messengers) directly onto the target tissues
Neuroendocrine reflex
Neurohormone (a substance released by a neuron) enters the blood to act on a remote target tissue.
No direct innervation
3 parts of the nervous system
Afferent NS
Integrating centers
Efferent (peripheral) NS
Hypothalamus
Specialized ventral portion of the brain
consisting of groups of nerve cell bodies called
hypothalamic nuclei
Purpose of the kisspeptin feedback loops
System in the brain that regulates the release of gonadotropin-releasing hormone (GnRH)
(Understand the diagrams)
Kisspeptin negative feedback loop (in males?)
Kisspeptin (in the hypothalamus) releases GnRH which stimulates the GnRHR (at the pituitary) to release LH and FSH to LHR and FSHR (in the gonads)
LH produces estradiol, testosterone and inhibin, which blocks kisspeptin and GnRHR
FSH produces inhibin which blocks GNRHR
Kisspeptin-estrogen feedback loop
Kisspeptin releases GnRH
-GnRH/LH surge causes ovulation, releases lots of estrogen, stimulates more kisspeptin production
-GnRH/LH pulses causes follicular development, releases small amounts of estrogen, prevents less kisspeptin production
Hypothalamus-Hypophyseal Portal System
Network of blood vessels that carries hormones from the hypothalamus to the pituitary gland
What does the strength of a hormone depend on
-Pattern and duration of secretion
-Half-life
-Receptor density
-Hormone-receptor affinity
The Bruce effect
-Pregnancy termination in recently pregnant
female rodents upon exposure to unfamiliar males
-Caused by male pheromone exocrine gland-secreting peptide 1 (ESP1) which is detected in the vomeronasal ensory neurons andsuppresses prolactin surges
