Neuroendocrine Control

Question 1

what is neuroendocrine control

Answer 1

secretion of hormones from the pituitary gland is closely controlled by the brain, especially by the hypothalamus
- hypothalamus-pituitary unit is the central regulator of endocrine function

Question 2

what is the development of the HP axis

Answer 2

-cells will start moving forward and pouching downward to form brain and ectoderm from the roof of the mouth pushing upward = rathkes pouch
- the ant pit cells detach from the mouth cells and wraps around the stock of the posterior pituitary

Question 3

what is the pars tuberalis

Answer 3

wrapped around the stock
= portal vessels of the portal systems pass near of through the pars tuberalis to the capillary beds of the pars distalis - its the communicator of the ant pit and the pos pit

Question 4

what is the pars intermedia

Answer 4

portion of the ant pit that makes contact with the pars nervosa in the PP in human fetus, very active in making melanocyte stimulating hormone

Question 5

what is the infundibular stalk

Answer 5

carries axons from the neurosecretory cells of the hypothalamus down to the posterior pituitary where they release hormones into their blood

Question 6

what are the main hormones in neuroendocrine functions

Answer 6

hypothalamus - the actual brain, produces releasing hormones, regulatory neuropeptides and prevent the release of others
pituitary - the sight of release
pineal - melatonin
sympathoadrenal medulla - catecholamines

Question 7

What does the hypothalamus release?

Answer 7

GnRH GHRH CRH PRH TRH

Question 8

what does the ant pit release

Answer 8

PRL GH FSH LH ACTH TSH

Question 9

what deos the posterior release

Answer 9

oxytocin and vasopressin (ADH)

Question 10

what function does the hypothalamus hold

Answer 10

endocrine, autonomic, somatic and emotional functions
- control of body temerature
- control of blood pressure and circulation
-regulation of food and water intake
- maintain homeostasis

Question 11

what mechanisms does the hypothalamus have

Answer 11

Neural signals - parasympathetic and sympathetic effects (allows for control of heart rate, vasoconstriction digestion and sweating
Endocrine signals - release neurohormones into general circulation via posterior pituitary (release neurohormones into blood portal system ( releasing hormones ) to regulate function of the anterior pit

Question 12

what are the specific neuroendocrine functions of the hypothalamus

Answer 12

send signals down the stock via axons - released into blood stream
releases to acess and stimulate other cells
motor fibers stimulate acetycholine and catocomines from rhe adrenal gland

Question 13

what is a magonocellular neuron?

Answer 13

large and long
somas (cell bodies) in the supraoptic nucleus (SON) and paraventricular nucleus (PVN)
axons terminate in the posterior pituitary
secrete antidiuretic hormone (ADH) and oxytocin

Question 14

what is s parvocellular neuron

Answer 14

small and short
cell bodies in the various nuclei
axons only reach the median eminence
secrete multiple releasing hormons

Question 15

what are the target tissues for VP and oxitocin

Answer 15

VP - kidneys
oxcitocin - mammary glands and uterine tissues

Question 16

what is the role of ADH

Answer 16

conserves body water and regulates tonicity
stimulates insertion of water channels or aquaporins into the membranes of kidney tubules

Question 17

what happens if your body cannot loose anymore water

Answer 17

a signal is sent to the hypothalamus to create auqporins that allows solute free water to exit the filtrate bringing water back into the blood system

Question 18

what happens if there is a lack of ADH secretion

Answer 18

creates diabetes insipidus
kidneys will make a lot of urine
dehydration and excessive thirst
can be treated with exogenous ADH
when osmolarity increases above the threshold the ever alert osmoreceptors recognize this as their cue to stimulate the neurons that secrete AHD

Question 19

why are nausea and vomiting stimulators of ADH

Answer 19

there is a massive loss in electrolytes - loosing sweet and casueing mOs to ggo up

Question 20

what is the role of oxytocin

Answer 20

ejects milk from lactating mammary glands in the brest via contraction of myoepithelial cells (suckling response)
enhances contraction of smooth muscle of the uterus during parturiton in response to dilation of the cervix