5.4 Hormonal communication

Question 1

What are the two types of hormones and give examples?

Answer 1

protein and peptide hormones (e.g adrenaline, insulin, glucagon)
steroid hormones (e.g oestrogen, testosterone)

Question 2

Are protein hormones soluble in the phospholipid bilayer?

Answer 2

No, bind to receptors on the cell surface membrane and use secondary messengers inside the cell

Question 3

Are steroid hormones soluble in the phospholipids bilayer?

Answer 3

Yes, these hormones directly affect DNA within the nucleus

Question 4

How do endocrine cells release hormones into the blood?

Answer 4

There are no ducts so they are transported straight into the capillaries

Question 5

What are the endocrine glands?

Answer 5

pituitary gland
thyroid gland
adrenal gland
testes
ovaries

Question 6

What is activated when a protein hormone binds to a receptor on the cell surface membrane?

Answer 6

The G protein is activated which activates an effector molecule (e.g adenyl cyclase that converts ATP to AMP or cAMP) cAMP is the second messenger and can cause an enzyme cascade

Question 7

Where are the adrenal glands found?

Answer 7

just above the kidneys

Question 8

What are the 2 sections of the adrenal glands called?

Answer 8

adrenal cortex and adrenal medulla

Question 9

What are the 3 layers to the adrenal cortex?

Answer 9

zona glomerulosa - outer layer, secretes mineralocorticoids e.g aldosterone
zona fasciculata - middle layer, secretes glucocorticoids e.g cortisol
zona reticularis - inner layer, secrete precursor molecules used in sex hormones

Question 10

What does the adrenal medulla secrete?

Answer 10

adrenaline and noradrenaline

Question 11

What type of hormones are secreted from the adrenal cortex?

Answer 11

steroid hormones

Question 12

What is the role of mineralocorticoids?

Answer 12

control concentrations of sodium and potassium in the blood. Also maintain blood pressure. Aldosterone acts on the distal tubules and collecting ducts.

Question 13

What is the role of glucocorticoids?

Answer 13

control metabolism of carbohydrates, fats and proteins in the liver. Cortisol is released in response to stress or low blood glucose concentration.

Question 14

Is adrenaline polar or non polar?

Answer 14

A polar molecule derived from the amino acid tyrosine.

Question 15

What response does adrenaline produce in the body?

Answer 15

• relaxing smooth muscle in bronchioles
• increase stroke volume
• increase heart rate
• causing vasoconstriction to raise blood pressure
• stimulating conversion of glycogen to glucose
• dilating the pupils
• increasing mental awareness
• inhibiting the action of the gut
• causing body hair to stand erect

Question 16

Where is the pancreas found?

Answer 16

below the stomach

Question 17

What are the two main secretions of the pancreas?

Answer 17

pancreatic juices with enzymes used in the small intestine
hormones secreted from the islets of langerhans

Question 18

What is the name for the group of cells involved in exocrine function of the pancreas?

Answer 18

acinus (plural acini)

Question 19

Where do the acini secrete the enzymes to?

Answer 19

A tubule in the middle of the group that form intralobular ducts that eventually form the pancreatic duct

Question 20

What is in the pancreatic fluid?

Answer 20

pancreatic amylase - carbohydrase that digests amylose into maltose
trypsinogen - inactive protease that is converted to trypsin when in the duodenum
lipase - digests lipid molecules

Question 21

what neutralises the ph of the pancreatic fluid?

Answer 21

sodium hydrogencarbonate

Question 22

what do the alpha and beta cells in the pancreas produce in the endocrine system?

Answer 22

alpha - glucagon
beta - insulin

Question 23

page 69 insulin cycle diagram

Question 24

what is the typical concentration of blood glucose?

Answer 24

4-6 mmol dm -3

Question 25

what is it called when blood glucose goes too high or too low ?

Answer 25

< 4mmol = hypoglycaemia
> 6 mmol = hyperglycaemia