30 Blood glucose and diabetes

Question 1

what is the difference between an endocrine and an exocrine gland?

Answer 1

endocrine = secretes hormones into the blood

exocrine = secretes other substances into ducts

Question 2

what are the names and functions of the two types of cells in islets of langerhans in the pancreas?

Answer 2

α = produce and secrete glucagon

β = produce and secrete insulin

Question 3

what colours are:
- endocrine tissue
- exocrine tissue
- capillaries
in the pancreas on a light micrograph?

Answer 3

• pale purple
• dark purple
• white

Question 4

describe how the pancreas responds to hyperglycaemia

Answer 4

β cells act as receptors –> detect rising blood glucose concentration

β cells secrete insulin

insulin binds to membrane-bound receptors on cells (muscle and liver)

Question 5

describe the effects of insulin secretion by the pancreas

Answer 5

target effector cells increase their uptake of glucose

glucose converted to fats or used in respiration

liver cells covert glucose to glycogen in glycogenesis and stored

blood glucose concentration falls

Question 6

describe how the pancreas responds to hypoglycaemia

Answer 6

α cells act as receptors –> detect falling blood glucose concentration

α cells secrete glucagon

glucagon binds to membrane-bound receptors on liver cells

Question 7

describe the effects of glucagon secretion by the pancreas

Answer 7

use of glucose as a respiratory substrate decreases

more fatty acids used as alternative respiratory substrates

liver cells convert glycogen to glucose in glycogenolysis, and release it into the blood stream

some amino acids and fats converted to glucose in gluconeogenesis

blood glucose concentration rises

Question 8

what is the normal range of blood glucose?

Answer 8

3.89 - 5.83 mmol dm^-3

Question 9

define diabetes mellitus

Answer 9

blood glucose concentration outside the normal range

Question 10

what is the difference between type 1 and type 2 diabetes?

Answer 10

type 1 = little/no insulin production due to autoimmune response

type 2 = reduced insulin production due to effector cells losing responsiveness to insulin

Question 11

what are the risk factors of type 1 diabetes?

Answer 11

heritability = several gene variants (e.g. some HLA antigens)

environmental (e.g. viral infections)

Question 12

what are the risk factors of type 2 diabetes?

Answer 12

obesity

genetics

age

hypertension

low birth weight

Question 13

describe the chemical reactions of a glucose biosensor

Answer 13

sterile lancer produces a drop of blood

test strip contains glucose oxidase

glucose oxidase converts glucose to gluconolactone

produces small electrical current

digital reading produced from electrode conversion

Question 14

describe how a doctor can test blood glucose levels

Answer 14

glucose molecules attach to haemoglobin –> glycosylated haemoglobin

blood glucose increase –> concentration of glycosylated haemoglobin increase

Question 15

how is type 1 diabetes managed?

Answer 15

insulin injections

Question 16

how is type 2 diabetes managed?

Answer 16

lifestyle changes (e.g. increased exercise; smaller meals)

metformin - reduces glucose production by the liver and glucose absorbtion from food

Question 17

describe the role of the following health professionals in the management of diabetes:
- diabetic nurse

• regular health checks by a consultant
• podiatrists

Answer 17

• education, advice and support
• blood pressure checks, eye tests, kidney function tests
• increasing blood supply to feet, changing footwear