Intro to endocrine system

Question 1

what are neuromodulators released by and what type of responses do they produce?

Answer 1

neurons and astrocyte.

slower pre- and post-synaptic responses.

Question 2

what are neurotrophic factors mainly released by and what do they control?

Answer 2

non-neuronal cells and on tyrosine-kinase linked receptors that regulate gene expression and control neuronal growth and phenotypic characteristics.

Question 3

which agents can act through ligand-gated channels and G-protein coupled receptors, functioning as both neurotransmitter and neuromodulator?

Answer 3

glutamate
5-hydroxytriptamine
acetylcholine

Question 4

which chemical mediators are produced by glia and neurons?

Answer 4

NAG:
nitric oxide
arachidonic acid
glutamate

Question 5

what are the two posterior pituitary hormones?

Answer 5

oxytocin

ADH

Question 6

what are the major types of receptors that hormones act on?

Answer 6

tyrosine kinase receptors
G-protein coupled receptors
steroid hormone receptors

Question 7

outline the action of hormones on steroid hormone receptors

Answer 7

hormone crosses membrane.
binds to cytoplasmic or nuclear receptor.
hormone-receptor complex binds to hormone response element of DNA to influence gene transcription.
receptor may be constitutively active.

Question 8

outline the action of hormones on G-protein coupled receptors

Answer 8

hormone binds to 7TM receptor.
causes synthesis of a 2nd messenger (inositol triphosphate/cyclic AMP).
2nd messengers phosphorylate intracellular, regulatory protein to influence cellular activity (e.g. smooth muscle contraction).

Question 9

outline the action of hormones on tyrosine kinase receptors

Answer 9

2 receptors required for hormone action on membrane-bound enzyme.
1 hormone binds to each receptor.
acts as an enzyme to phosphorylate tyrosine components of intracellular, regulatory proteins.

Question 10

what are the characteristics of peptide hormones?

Answer 10

highly water soluble.
susceptible to protease attack.
unable to cross cell membrane without carrier protein.
act on membrane-bound receptors.

Question 11

what are the characteristics of steroid and thyroid hormones?

Answer 11

highly lipid soluble.
poorly water soluble.
must be transported in blood bound to plasma protein.
only unbound hormone biologically active.
able to cross cell membrane and act on intracellular receptors

Question 12

what are the differences between peptide hormones and steroid and thyroid hormones respectively?

Answer 12

water soluble V poorly soluble.
not orally active V active.
rapid onset of action V slow. 
short plasma half life V long.
short duration of action V long.
synthesised and stored as inactive precursor V synthesised on demand.

Question 13

what does the hypothalamus secrete?

Answer 13

releasing hormones

Question 14

what does the anterior pituitary gland secrete?

Answer 14

stimulating (or trophic) hormones