Endocrine

Question 1

what is an endocrine secretion

Answer 1

secretion from groups of cells organised into endocrine glands

Question 2

where do endocrine glands release secretions

Answer 2

into extracellular fluid which then moves into the blood stream

ductless

Question 3

where do exocrine glands release secretions

Answer 3

into ducts

Question 4

how are hormones transported around the body

Answer 4

dissolved in blood

attached to transporters in blood

Question 5

what is an example of an integrated functional endocrine system

Answer 5

hypothalamus releases CRF which acts on cells of the anterior pituitary gland causing it to release ACTH which enters the blood stream and binds to the adrenal cortex leading to production and release of cortisol

Question 6

how is specificity of hormone signalling achieved

Answer 6

• by chemical distinct hormones
• specific receptors for each hormones
• distinct distribution of receptors across target cells (localised)

every cell can be exposed to a hormone but only selective cells will respond - ones with the receptors

Question 7

what are the 7 classical endocrine organs in the body

Answer 7

Pituitary gland 
thyroid gland 
parathyroid gland 
adrenal glands 
pancreas 
ovaries  
testis

Question 8

what are the different types of hormone

Answer 8

modified amino acids
steroids
peptides
proteins

Question 9

what is an example of a modified amino acid hormone

Answer 9

adrenaline

thyroid hormones

Question 10

what is an example of steroid hormones

Answer 10

cortisone 
progesterone 
testosterone 
aldesterone 
-one

Question 11

what is an example of peptide hormones

Answer 11

ACTH
ADH -anti-diuretic
oxytocin

-derived from larger precursor proteins

Question 12

what is an example of a protein hormone

Answer 12

insulin

Question 13

what is autocrine signalling

Answer 13

cell is signalling to itself

Question 14

what is paracrine signalling

Answer 14

cell signals other cells close to it

Question 15

what is endocrine signalling

Answer 15

cell signals travel via molecules transported by the BLOOD to target distant cells

Question 16

what’s an example of overlap between different types of chemical signalling

Answer 16

somatostatin

paracrine in pancreas but endocrine in brain

Question 17

how potent are hormones

Answer 17

vv potent as they exist at a very low concentration in the body

Question 18

hormones can have an effect on multiple specific targets true/false

Answer 18

true

Question 19

only one hormone can have an effect on a target true/false

Answer 19

false

multiple hormones can affect the same target

Question 20

how is the biological response caused by a hormone initiated

Answer 20

active receptor engages in signal transduction cascade causing amplification of the original signal

Question 21

the speed/onset/duration of hormone action variable true/fasle

Answer 21

true

seconds - days

Question 22

how is hormone signalling terminated

Answer 22

by enzyme-mediated metabolic inactivation in the liver or at sites of action

Question 23

what is the complementary action of hormones

Answer 23

when several hormones work together to produce the same effect

eg. adrenaline, cortisol and glucagon all contribute to the body in short term exercise

Question 24

what is an antagonistic action of hormones

Answer 24

when hormones oppose each other

eg. insulin vs glucagon

Question 25

what does insulin do

Answer 25

lowers plasma glucose level by stimulating glucose uptake into muscle and adipose tissue and inhibiting gluconeogenesis and glyconeogenesis

Question 26

what does glucagon do

Answer 26

increased glucose level by stimulating glycogenolysis and and gluconeogenolysis but does not antagonise glucose uptake (adrenaline does)

Question 27

when are amines released

Answer 27

in response to stimuli by Ca++ dependent exocytosis

Question 28

how is adrenaline/amines stored

Answer 28

as a pre-synthesised hormone

Question 29

what makes amines easy to transport around the body

Answer 29

its hydrophilic nature allows it to dissolve in blood

Question 30

how are peptides and protein hormones stored

Answer 30

as presynthesied hormones formed from long precursor proteins

Question 31

when are peptide and protein hormones released

Answer 31

in response to stimuli by Ca++ demented exocytosis

Question 32

how are peptides transported in blood

Answer 32

freely due to hydrophilic nature

Question 33

how are steroids stored

Answer 33

synthesised and released on demand in order for cell to release a steroid hormone the signal must initiate synthesis

Question 34

how are steroid hormones transported around the body

Answer 34

hydrophilic so 90% transported in plasma bound to proteins only the 10% which is unbound which is biologically active - only this can cross the capillary role - rest is confined to the plasma

Question 35

is steroid release quicker or slower than peptide hormone releases

Answer 35

slower as they need to be synthesised first

Question 36

what do carrier transport proteins do

Answer 36

increase amount transported in blood provide reservoir of hormone extend half life of hormone in circulation

Question 37

what are 3 important specific carrier proteins

Answer 37

cortisol-binding globulin thyroxine-binding globulin sex steroid-binding globulin

Question 38

2 important general carrier proteins

Answer 38

albumin - binds many steroids and thyroxine transthyretin - binds thyroxine and some steroids

Question 39

how do carrier proteins help to maintain constant concentration of free lipophlillic hormone in blood

Answer 39

as the free hormone in the plasma is removed by crossing the capillary wall, it is replaced by hormone which is already bound to the carriers in blood

Question 40

why is it only free hormone that can initiate biological response

Answer 40

because the carrier protein cant cross the capillary wall

Question 41

what is the primary determinant of plasma concentration of hormone

Answer 41

the rate of secretion

Question 42

what is the classic example of the control of secretion of hormone

Answer 42

HPA axis cortisol negatively feed backs on the pituitary and hypothalamus glands negative feedback maintains plasma concentration at a set level

Question 43

how does the neuroendocrine system affect hormones

Answer 43

stress elicits sudden burst in secretion in response to a specific stimulus

Question 44

what is the general pattern of hormone secretion

Answer 44

diurnal (circadian) rhythm secretion fluctuates as a function of time

Question 45

how do u work out the plasma concentration of a hormone

Answer 45

it = the rate of secretion - rate of elimination

Question 46

what is the most common routes of hormone elimination

Answer 46

local metabolism by liver | excretion by kidney

Question 47

what are the 3 main types of hormone receptors

Answer 47

G-protein coupled receptors Receptor Kinases Nuclear receptors

Question 48

what activates G-protein couples receptors

Answer 48

amines and some proteins. peptides located at surface of cell bc these proteins are hydrophilic

Question 49

what activates receptor kinases

Answer 49

proteins/ peptides | located at the surface of the cell bc these proteins are hydrophilic

Question 50

where are the nuclear receptors found

Answer 50

inside the cell either in cytoplasm or nucleus

Question 51

where are class 1 nuclear receptors found and what activated them

Answer 51

in the cytoplasm- bound to heat shock proteins - unbind and move to nucleus when activated steroids activate them

Question 52

where are class 2 nuclear receptors found what activated them

Answer 52

in the nucleus activated by lipids

Question 53

what activates hybrid class nuclear receptors

Answer 53

thyroid hormone

Question 54

look at g-protein coupled receptor pathway

Answer 54

look at adrenaline pathway | angiotensin 2 pathway

Question 55

what is an example of signalling via receptor kinases

Answer 55

the receptor for insulin absence of insulin - no signalling when insulin binds - beta subunits gain enzymatic activity by increase of tyrosine kinase activity- allows the receptor to phosphorylate itself - allows binding of insulin receptor substrate proteins which signals to protein kinase B producing metabolic effects