5.1.4 - hormonal communication

Question 1

endocrine glands

Answer 1

group of cells which are specialised to secrete chemicals (hormones) directly into the bloodstream

Question 2

pituitary gland

Answer 2

produces growth hormone, ADH, and gonadrotrophins

Question 3

thyroid gland

Answer 3

produces thyroxine, controlling the rate of metabolism

Question 4

adrenal gland

Answer 4

produces adrenaline

Question 5

testis

Answer 5

produces testosterone

Question 6

pineal gland

Answer 6

produces melatonin

Question 7

thymus

Answer 7

produces thymosin

Question 8

pancreas

Answer 8

produces insulin

Question 9

ovary

Answer 9

produces oestrogen

Question 10

hormones

Answer 10

chemical messengers that are secreted directly into the blood when a gland is stimulated. they will then bind to specific target cells

Question 11

steroid hormones

Answer 11

lipid soluble and can pass through the phospholipid bilayer, and bind to specific receptors to form a hormone receptor complex
e.g. oestrogen

Question 12

how can a steroid hormone act as a transcription factor?

Answer 12

it in turn facilitates or inhibits the transcription of a specific gene

Question 13

non steroid hormones

Answer 13

hydrophillic - cannot pass directly through the cell membrane - and instead bind to receptors on the cell membrane of the target cell, triggering a cascade reaction

Question 14

two parts of the adrenal gland

Answer 14

the adrenal cortex (outer region)
the adrenal medulla (inner region of the gland)

Question 15

main types of hormones produced in the adrenal cortex

Answer 15

• glucocorticoids including cortisol - regulating metabolism, and blood pressure
• mineralocorticoids including aldosterone - helps control blood pressure
• androgens - small amount of male and female sex hormones

Question 16

exocrine gland in the pancreas function

Answer 16

• to produce enzymes and release them via a duct in the duodenum

Question 17

endocrine gland in the pancreas function

Answer 17

to produce hormones and release them into the blood

Question 18

digestive enzymes that the pancreas produces (exocrine)

Answer 18

amylases - break down starch into simple sugars

proteases - break down proteins into amino acids

lipases - break down lipids into fatty acids and glycerol

Question 19

what are islets of Langerhans?

Answer 19

within the exocrine tissue tehre are small regions of endocrine tissue - responsible for producing insulin and glucagon and secreting these hormones directly into the bloodstream

Question 20

how do the islets of Langerhans appear under a microscope

Answer 20

lightly stained, large spherical clusters

Question 21

what cells are in the islets of Langerhans

Answer 21

• a alpha cells (produce and secrete glucagon)
• b beta cells (produce and secrete insulin)

Question 22

why does blood glucose concentration increase?

Answer 22

• diet (carb rich foods, and sweeter foods - the carbs break down and release glucose into blood)
• glycogenolysis
• gluconeogenesis

Question 23

what is glycogenolysis?

Answer 23

glycogen stored in the liver and muscle cells is broken down into glucose and released intobloodstream, increasing blood glucose concentration

Question 24

gluconeogenesis?

Answer 24

production of glucose from non carb sources, e.g. liver making glucosw from glycerol and amino acids

Question 25

how can blood glucose concentration be decreased?

Answer 25

respiration - glucose is usded by cells to release energy glycogenesis - production of glycogen

Question 26

how does insulin lower the blood glucose concentration?

Answer 26

- increase rate of absorption of glucose by cells - increasinng respiratory rate of cells - increase glycogenesis -increasing rate of glucose to fat conversion - inhibiting release of glucagon

Question 27

how is insulin broken down

Answer 27

by ezymes in the cells of the liver

Question 28

what detects that the blood glucose concentration has gone back to normal?

Answer 28

the b cells reducing the secretion of insulin

Question 29

how does glucagon raise blood glucose concentration?

Answer 29

- glycogenolysis - reducing amount of glucose absorbed by the liver cells - increasing gluconeogenesis

Question 30

mechanism of insulin secretion steps

Answer 30

1. glucose enters the cell 2. respiration 3. production of ATP 4. ATP binds to potassium channels, causing them to close 5. this abundance of K+ ions in the cell, causes membrane depolarisation 6. this depolarisation causes the voltage dated calcium channels to open 7. calcium ions enter the cell (Ca2+ influx) 8. this them causes the vesicles containing insulin to move, and release by exocytosis

Question 31

symptoms of diabetes

Answer 31

- high blood glucose conc - glucose present in urine - excessive need to urinate - execessive thirst - constant hunger - weight loss - blurred vision - tiredness

Question 32

type one diabetes

Answer 32

unable to produce insulin as the b cells in the islets do not produce them

Question 33

cause of type one diabetes

Answer 33

unknown but in many causes it may be due to an autoimmune response where the bodys own immune system attacks the b cells

Question 34

treatment of type one diabetes

Answer 34

regular injections of insulin which requires careful monitoring of doses

Question 35

hypoglycaemia

Answer 35

very low blood glucose

Question 36

hyperglycaemia

Answer 36

too high an insulin dose

Question 37

type two diabetes

Answer 37

cannot effectively use insulin and control blood sugar levels, as the glycoprotein insulin receptor on the cell membrane does not work properly meaning the cells lose the responsiveness to insulin.

Question 38

cause of type two diabetes

Answer 38

excess body weight, physical inactivity, and overeating of carbs

Question 39

treatment of type 2 diabetes

Answer 39

regulate a persons diet, and increasing exercise levels drugs