endocrine systems and receptors

Question 1

how do ligand gated ion channels open?

Answer 1

-hormone binds to ligand gated ion channel causing them to open

Question 2

how do G protein couples receptors work?

Answer 2

• the ligand agonist (hormone) will bind to the membrane bound G protein coupled receptor causing a conformational change
• this allows the G alpha subunit to bind to the G protein coupled receptor
• The GDP bound to the alpha subunit becomes GTP, activating the alpha subunit, allowing it to bind to an adjacent enzyme causing a cellular response
• the G alpha subunit stop signalling once GTP becomes GDP again

Question 3

where are a2 adrenoceptors located?

Answer 3

the gut

Question 4

summary table of G protein coupled receptors!! (not question)

Answer 4

Question 5

what unique about kinase linked receptors?

Answer 5

-you can get lots of different cellular responses

Question 6

how long is the cellular response in kinase linked receptors?

Answer 6

the response can be going on for hours e.g. insulin binding to insulin receptor

Question 7

what is autocrine regulation

Answer 7

when chemicals (i.e. signalling molecules) released from the cells bind to receptors on or in the cell that is releasing them (gives negative feedback)

Question 8

what is paracrine regulation?

Answer 8

chemicals (i.e. signalling molecules) released from the cells bind to receptors on adjacent cells

Question 9

what is endocrine regulation?

Answer 9

chemicals (i.e. hormones) released from the secretory cells are usually transported via the circulatory system

Question 10

what provides the highest level of endocrine control?

Answer 10

hypothalamus

Question 11

what is the endocrine director?

Answer 11

hypothalamus

Question 12

how does the hypothalamus integrate activities of nervous and endocrine system ?

Answer 12

by:

• secretion of regulatory hormones
• synthesys of hormones
• direct neural control

Question 13

True or False

Hormone levels are not influenced by the rate at which they are eliminated from the body?

Answer 13

False

Hormones are influenced by the rate at which they are eliminated from the body

Question 14

what affect does cortisol have on glucose?

Answer 14

cortisol triggers gluconeogenesis and so increases blood glucose

Question 15

what are the 3 classes of hormones?

Answer 15

• steroids
• amine dervies
• proteins

Question 16

whats an example of a steroid hormone?

Answer 16

oestrogen

Question 17

whats an example of an amine derived hormone?

Answer 17

• adrenaline

- epinephrine

Question 18

whats an example of a protein hormone?

Answer 18

• oxytocin
• ADH
• growth hormone
• insulin

Question 19

what are steroid hormones derived from?

Answer 19

steroids are lipids derived from cholesterol

Question 20

are steroids hydrophobic or hydrophilic?

Answer 20

hydrophobic

Question 21

how are steroids transported in blood?

Answer 21

-transported in blood plasma by binding to carrier proteins (about 90%)

Question 22

when are steroids biologically active?

Answer 22

when they are free or unbound

Question 23

are peptide hormones hydrophilic or hydrophobic?

Answer 23

hydrophilic

Question 24

how are peptide hormones transported in the blood?

Answer 24

unbound or ‘free’ in blood plasma

Question 25

where are peptide hormones secreted?

Answer 25

by pituitary, parathyroid, heart, stomach, liver and kidneys

Question 26

how are peptide hormones synthesised and stored?

Answer 26

they are synthesised as precursor molecules and stored in secretory vesicles

Question 27

are amine hormones hydrophobic or hydrophilic?

Answer 27

hydrophilic

Question 28

how are amine hormones transported?

Answer 28

• catecholamine amine hormones are hydrophilic and are transported unbound or ‘free’ in blood plasma
• thyroid amine hormones are bound to carrier proteins

Question 29

where are amine hormones secreted from?

Answer 29

-thyroid and adrenal medulla

Question 30

whats an example of an amine hormone?

Answer 30

adrenaline

Question 31

what are amine hormones derived from?

Answer 31

derived from amino acids (e.g. adrenaline derived from tyrosine)

Question 32

how are steroid and thyroid hormones transported?

Answer 32

-they are insoluble in plasma and are transported in blood via carrier protein

Question 33

what does binding of steroid and thyroid hormones to the carrier proteins do for the hormones?

Answer 33

• facilitation of hormone transport
• increased half life of hormones
• a reservoir for the hormone

Question 34

what does cortisol- binding globulin (CBG) bind to?

Answer 34

-it is a specific carrier proteins and so binds to cortisol in a selective manner (also some aldosterone)

Question 35

what does thyroxine-binding globulin (TBG) bind to?

Answer 35

it is a specific carrier protein so binds to thyroxine T4 selectively (also some triidothyronine T3)

Question 36

what does sex steroid binding globulin (SSBG) bind to?

Answer 36

it is a specific carrier protein so mainly binds to testosterone and oestradiol

Question 37

Hormones secreted by hypothalamus and pituitary gland table (no question)

Answer 37

Question 38

hormones secreted by endocrine glands table (no question)

Answer 38

Question 39

hormones secreted by endocrine glands table (no question)

Answer 39

Question 40

examples of endocrinopathies (no question)

Answer 40

Question 41

examples of endocrinopathies (no question)

Answer 41