Biochemistry - Endocrine

Question 1

which cells in the islets of langerhans secrete insulin?

Answer 1

beta cells

Question 2

which cells in the islets of langerhans secrete glucagon?

Answer 2

alpha cells

Question 3

which cells in the islets of langerhans secrete somatostatin?

Answer 3

delta cells

Question 4

what is the initial structure that is cleaved to form insulin?

Answer 4

preproinsulin

Question 5

true or false: there is great variation in the amino acid sequence of insulin between species

Answer 5

false

very little variation

Question 6

what is the effect of insulin upon amino acids, glucose and lipids?

Answer 6

increases uptake into respective tissues

Question 7

true or false: insulin inhibits lipolysis

Answer 7

true

Question 8

through which transporter does glucose enter beta cells in the pancreas?

Answer 8

GLUT2

Question 9

what happens to glucose once in the beta cell in the pancreas?

Answer 9

phosphorylated to glucose 6 phosphate

Question 10

which enzymes carry out glucose phosphorylation?

Answer 10

glucokinase

hexokinase (RBCs)

Question 11

which two proteins make up a functional Katp channel?

Answer 11

Kir 6.1

sulphonylurea receptor (SUR1)

Question 12

what inhibits the Katp channel?

Answer 12

intracellular ATP

Question 13

what happens as a result of inhibition of the Katp channel?

Answer 13

depolarisation, causing opening of calcium channels to allow insulin exocytosis

Question 14

what is MODY?

Answer 14

maturity onset diabetes of the young

Question 15

what causes MODY?

Answer 15

a genetic defect in beta cell function, causing early onset type II diabetes

Question 16

which enzyme is impaired in MODY?

Answer 16

glucokinase

Question 17

how are ketone bodies formed?

Answer 17

derived from acetyl-CoA in beta oxidation

Question 18

name three ketone bodies

Answer 18

acetone
acetoacetic acid
B-hydroxybutric acid

Question 19

which type of diabetes is ketoacidosis most associated with?

Answer 19

type 1

Question 20

true or false: sodium follows water everywhere

Answer 20

false

water follows sodium

Question 21

true or false: concentration of sodium inside the cell is greater than outside the cell

Answer 21

false

Question 22

what does mineralocorticoid activity refer to?

Answer 22

sodium retention in exchange for potassium and/or hydrogen ions

Question 23

what is the main steroid in the body with mineralocorticoid activity?

Answer 23

aldosterone

Question 24

what does excess mineralocorticoid activity cause?

Answer 24

sodium retention ‘

Question 25

what effect does sodium loss have upon water?

Answer 25

sodium loss means water loss

Question 26

outline what happens in terms of sodium and water when BP drops

Answer 26

decreased BP causes sodium and water retention, in order to compensate and bring blood pressure up

Question 27

which hormone controls water reabsorption?

Answer 27

ADH

Question 28

what effect does ADH have on water reabsorption and thus urine output?

Answer 28

causes increased water reabsorption producing low volume concentrated urine

Question 29

true or false: concentrated/small volume urine has a high osmolality

Answer 29

true

Question 30

what are the main causes of decreased sodium levels/

Answer 30

too much water | too little sodium

Question 31

what are the main causes of increased sodium levels?

Answer 31

too little water | too much sodium

Question 32

how can too much water cause decreased sodium levels?

Answer 32

SIAD | compulsive water drinking

Question 33

how can too little sodium cause decreased sodium levels?

Answer 33

sodium loss | decreased sodium intake

Question 34

how can increased sodium levels be due to too little water?

Answer 34

water loss | decreased water intake

Question 35

how can too much sodium increase sodium levels?

Answer 35

IV medication drowning in the sea high salt foods

Question 36

outline the pathogenesis of addison's disease

Answer 36

1. adrenal insufficiency 2. cant make enough aldosterone 3. cant retain enough sodium 4. lose sodium and water 5. low ECFV, patient is dehydrated and dizzy

Question 37

what is the main osmotic stimulus for ADH release?

Answer 37

high sodium causes increased ADH

Question 38

does hypovolaemia cause increased or decreased ADH release?

Answer 38

increased to compensate for fluid loss

Question 39

outline pathogenesis of diabetes insipidus

Answer 39

1. disrupted pituitary 2. can't secrete ADH 3. less water reabsorption 4. lots of water lost in urine 5. sodium is high to reflect water deficit