Week 6 Flashcards

Question

Alpha cells

Answer 1

Secrete glucagon as a response to low blood glucose 29-amino-acid polypeptide Potent hyperglycaemic agent Major target= liver Promotes: glycogenolysis, gluconeogenesis, release of glucose to blood from liver cells

Answer 2

The breakdown of glycogen to glucose-1-phosphate and glucose

Answer 3

Synthesis of glucose from lactic acid and non-carbohydrates inside the liver and kidneys Stimulated by glucagon

Answer 4

Secrete insulin 51-amino-acid protein 2 amino acid chains linked by disulphide bonds Synthesised as part of pro-insulin Cleaved to make functional insulin Potent hypoglycaemic agent Enhances transport of glucose into cells Counters metabolic activity that would enhance blood glucose levels

Answer 5

Insulin receptor- tyrosine kinase enzyme After glucose enters a cell, insulin binding triggers enzymatic activity that: Catalyses oxidation of glucose for ATP production Polymerises glucose to from glycogen Converts glucose to fat especially in adipose tissue

Answer 6

Low blood sugar

Answer 7

High blood sugar

Answer 8

Pancreatic B cells secrete insulin -regulated by plasma glucose levels Lowers blood glucose Glucose enters B cells by glucose transport molecule (GLUT 1,3), increasing production of ATP through a series of processes, this decreases activity of ATP-sensitive K+ channel , decreasing efflux of K+ leading to depolarisation (reduced Hyperpolarisation), this opens Ca2+ channels so Influx of Ca2+, leading to exocytosis of insulin

Answer 9

They become unresponsive to glucose or down regulate so can’t detect presence of glucose Glucose must be present for insulin to be secreted

Answer 10

1st phase- very rapid insulin secretion, after eating a meal 2nd phase- lower, reaches small intestine and is absorbed Type 2 diabetes only have the second peak Type 1 diabetes have no insulin peaks, excess glucose

Answer 11

In liver, muscle and fat Multi-subunit proteins: a (x2)- extracellular (binding site), b(x2)- transmembrane (tyrosine kinase) Phosphorylation of insulin receptor substrate IRS proteins Enzyme activation + gene transcription Increases glucose uptake (expression of GLUT-4 transporter) Increases glycogen synthesis Link between activity of insulin receptor and ability of glucose to enter cells

Answer 12

Tailored to each patient Carbohydrate counting- training Dietary advice: balanced diet Managing insulin doses to minimise glucose fluctuations when changing diet Exercise: reduced cardiovascular risk, effects on insulin dosage and carb intake, regulated HbA1c measurement Self monitoring of plasma glucose: finger prick regular times a day, continuous monitoring devices

Answer 13

HbA1c- glycated haemoglobin form of haemoglobin that’s chemically linked to sugar-glucose Measures amount of glucose attached to haemoglobin Reflects previous 10 weeks of ambient circulating glucose Gives a long term view on how good a persons glucose control has been >48mmol/mol =diabetes

Answer 14

Short acting- e.g. just before a meal, onset 30 mins, peak 2-4hrs, soluble insulin Long acting-simulate what you would see normally (2nd peak on graph), onset 1-2hrs, peak 4-12 hrs, insulin complexes. Different time regimes per patient

Answer 15

Still secrete insulin, no major loss of B cells Increased basal insulin levels in blood Loss of phase 1 of insulin secretion Insulin resistance: dysfunction of IR signalling cascade proteins, associated with inflammation in adipose tissue

Answer 16

Complex: genetics, socioeconomic factors, demographic factors Primary management: diet, exercise, lifestyle modification, intermittent fasting, very low calorie diets (VLCD)- not many compliant If doesn’t work: drugs ( ACE inhibitors, statins etc), 1/3 will eventually need insulin,

Answer 17

Decreases gluconeogensis, increases fatty acid oxidation, via activation of AMP-activated protein kinase, decreases carbohydrate absorption in intestine, increases glucose uptake by skeletal muscle Side effects: no hypoglycaemia, no increased appetite, lactic acidosis, gastrointestinal disturbances (has effect on flora in large intestine), slow release better It’s first choice drug

Answer 18

Beta cells- bind part of Katp channel Binding causes channel to close Depolarisation of beta cell Ca2+ entry and increased insulin secretion Increased tissue sensitivity to insulin Side effects: hypoglycaemia, diuretic actions

Answer 19

Rare, an undiagnosed or poorly controlled overactive thyroid can lead to life-threatening condition- thyroid storm Sudden flare up of symptoms such as very high body temperature, rapid heartbeat, shortness of breath Triggered by an infection, pregnancy, not taking medicine correctly

Answer 20

Na+/I- symporter

Answer 21

Caused by the immune system attacking the thyroid gland which damages it and makes it swell Can cause thyroid to not make enough thyroid hormone as thyroid is destroyed over time Symptoms may include: goiter, tiredness, weight gain, muscle weakness, dry skin. Symptoms of hypothyroidism

Answer 22

Levothyroxine taken to replace the missing thyroxine

Answer 23

Thionamides commonly used, they stop thyroid producing excess hormones Main types used are carbimazole and propylthiouracil

Answer 24

Serum thyroid stimulating hormone (TSH)

Answer 25

Carbimazole Propylthiouracil

Answer 26

Levothyroxine