Endocrinology

Question 1

Name five different types of intercellular communication

Answer 1

Direct, autocrine, paracrine, endocrine, synaptic

Question 2

Direct communication is possible because of the presence of

Answer 2

Connexons/Gap Junctions

Question 3

When a cell secretes a chemical messenger that binds to receptors on the same cell leading to changes in the cell

Answer 3

autocrine communication

Question 4

What is the difference between a hormone and a factor

Answer 4

The chemical structure of hormones is known, unknown for factors

Question 5

Pathway of hormone or paracrine

Answer 5

Hormone goes from interstitial fluid to circulatory. Paracrine stays in interstitial fluid

Question 6

Define Hormone

Answer 6

Chemical messenger that is released in one tissue and transported into the bloodstream to alter the activity of specific cells in other tissues

Question 7

Three ways hormones can affect function

Answer 7

1) act as a TF and stimulate synthesis of enzyme or protein 2) Regulate the rate of synthesis (increase/decrease) 3) Turn an existing enzyme of membrane channel on or off

Question 8

4 similarities between nervous and endocrine system

Answer 8

1) Both rely on release and binding of chemicals 2) Both systems share many chemical messengers (NE/E are hormone when in bloodstream, nT when released across synapse) 3) Both regulated by negative feedback 4) Share common goal, maintain homeostasis

Question 9

2 differences between nervous and endocrine system

Answer 9

1) NS for crisis management, short term homeostasis 2) NT release is in a very specific area

Question 10

Difference between endocrine and exocrine cells

Answer 10

endocrine cells release secretions into extracellular fluid and exocrine release onto epithelial surface

Question 11

Four classes of hormones

Answer 11

peptide, amino acid, lipid

Question 12

What two main amino acids are hormones are derived from

Answer 12

tyrosine- thyroid hormone, E, NE, dopamine (catcaholamines)

tryptophan- melatonin

Question 13

What makes peptide hormones unique?

Answer 13

they are synthesized as inactive prohormones and then converted to their active form before or after secretion

Question 14

What are the subclasses of peptide hormones

Answer 14

glycoproteins- FSH, LH, TSH (FLAT)
short polypeptides- OXT, ADH (posterior pituitary)
small proteins- GH, Prolactin (PIG)

Question 15

Where are most steroid hormones released from?

Answer 15

1) reproductive organs. androgens by testes in makes, prostaglandin by ovary in females
2) adrenal cortex- corticosteroid
3) kidney- calcitrol

Question 16

Do peptide hormones and catecholamines bind on the inner or outer surface of the plasma membrane? Which type of response is more rapid?

Answer 16

outer. they are not lipid soluble and this cannot cross the plasma membrane. Binding extracellular is faster

Question 17

What is the difference between a first and second messenger? What are examples of each?

Answer 17

First messenger (hormone) does something that leads to the appearence of the second messenger
Second Messenger (cAMP, cGMP, Ca2+)

Question 18

Explain mechanism of G protein and cAMP (5 steps)

Answer 18

1) hormone binds 2) G protein activated 3) G protein activates adynlate cyclase 4) adylnate cyclase turns ATP into cAMP 5)cAMP is a second messenger and activates a kinase 6)kinase phosphorylates proteins

Question 19

How is the level of cAMP lowered?

Answer 19

1) Hormone binds 2) G protein activated 3) G protein activated phosphodiesterase (PDE) 4) PDE inhibits adynlate cyclase activity and converts cAMP to AMP

Question 20

Explain the relationship between G proteins and Ca2+ ions

Answer 20

1) Hormone binds 2) G protein activated 3) G protein activates phospholipase C (PLC) 4) PLC triggers a cascade that produces DAG and IP3 from membrane phosplipid 5) IP3 diffuses to the cytoplasm and triggers the releae of calcium from intracellular reserves 6) DAG and Ca2+ together, activate protein kinase C (PKC) 7) PKC phosphorlates Ca2+ channel and extracellular calcium can enter cell 8) Ca2+ can act as a second messenger or with calmodulin

Question 21

E, NE, OXT binding to alpha 1 receptors leads to what kind of activation?

Answer 21

G protein and Ca2+ ion

Question 22

E and NE binding to alpha 2 receptors leads to what kind of response?

Answer 22

G protein and cAMP

Question 23

Explain how Thyroid hormones activate

Answer 23

Receptor intracellular 1) TH crosses PM by transport mechanism 2) When in cytoplasm, binds receptors in mitochondria or nucleus 3) complex binds to DNA 4) gene activated 5) transcription and mRNA production 6) translation and protein synthesis

Question 24

Three mechanisms of Hypothalamic Control over Endocrine function

Answer 24

1) Produces ADH and OXT
2) secretes regulatory hormones to control activity of anterior pituitary
3) control of sympathetic output to adrenal medullae

Question 25

What are other names for: Pituitary gland, anterior pituitary, posterior pituitary

Answer 25

Hypophysis, adenohypophysis, neurohypophysis

Question 26

What are the 3 regions of anterior pituitary and what are the general functions of each

Answer 26

Pars Distalis- largest and most anterior portion where the bulk of the hormones are synthesized
Pars tuberalis- wraps around infindibulum
Pars Intermedia- sots between pars distalis and posterior pituitary

Question 27

Names of hormones released from anterior pituitary and hormones that stimulates

Answer 27

FSH, LH--> GnRH (ovary/testes)
ACTH-->CRH (adrenal cortex)
TSH--> TRH (thyroid)
Prolactin--> (- dopamine) (mammary gland
GH--> GhRH (all body cells)

Question 28

What hormone is released from the pars intermedia?

Answer 28

MSH- melanocyte releasing hormone
inhibited by dopamine
only in fetal dvlpmnt, young children, pregnt, diseased states

Question 29

What hormones are released from the posterior pituitary?

Answer 29

ADH and OXT

Question 30

What is diabetes insipidus

Answer 30

PP not release enough ADH, lots of water lost. always thirsty but body not retain water