Endocrine System 2

Question 1

What 2 subdivisions make up amino acid derivatives

Answer 1

• catecholamines

- thyroid hormones

Question 2

give some examples of peptide hormones

Answer 2

• ADH, oxytocin, the majority

Question 3

which hormones are lipid soluble

Answer 3

• thyroid hormones and steroid hormones

Question 4

what are the 3 ways the hypothalamus controls hormone production

Answer 4

1) secretion of regulatory hormones into the primary plexus which travels to the anterior lobe of the pituitary gland
2) Neurones from hypothalamus to posterior lobe of pituitary gland cause release of ADH and oxytocin
3) Control and release of catecholamines from the adrenal gland by motor fibres or sympathetic NS

Question 5

how does the hypothalamus control the release of hormones from the posterior pituitary lobe

Answer 5

• osmoreceptors and other sensory receptors detect and trigger nervous stimulation in the hypothalamus which travels down to the posterior pituitary lobe where ADH or Oxytocin is secreted into the capillary plexus

Question 6

what are the hormones released from the posterior pituitary lobe

Answer 6

• ADH

- Oxytocin

Question 7

how does ADH affect the body

Answer 7

• ADH targets kidney cells to increase water reabsorption, increasing blood volume/pressure and hydration

Question 8

how does oxytocin affect the body?

Answer 8

women: stimulates labour uterus contractions during childbirth
men: stimulates the smooth muscles in ductus deferens and prostate

Question 9

what are somatomedins

Answer 9

• growth factor hormones released from liver cells when stimulated by growth hormones from the anterior pituitary gland

Question 10

what do somatomedins do?

Answer 10

• stimulate tissue growth

- increase amino acid uptake and protein synthesis

Question 11

what effect can growth hormone directly from the anterior pituitary lobe have?

Answer 11

• it can target liver cells to release somatomedins
• it can stimulate cell division
• it can stimulate fat breakdown in adipose cells
• stimulate liver glycogen breakdown

Question 12

describe the thyroid gland

Answer 12

• in neck
• made of 2 lobes connected by the narrow isthmus (like a bowtie)
• stores and secretes thyroid hormones thyroxine and triiodothyronine

Question 13

what do thyroid hormones do and why is this important

Answer 13

increase sodium potassium ATPase production

- important for resting potentials and maintaining membrane potentials

Question 14

Describe how the thyroid gland produces thyroid hormones

Answer 14

• there are large follicles in the thyroid gland which contain a protein rich fluid (colloid)
• when iodine id digested and absorbed it is incorporated with the colloid to make thyroid hormones
• the thyroid hormone remains stored in the follicles until released

Question 15

what kind if cell line the follicles in thyroid gland

Answer 15

• cuboidal epithelium follicle cells and they also produce the colloid fluid

Question 16

what are the effects of thyroid hormones

Answer 16

• increase energy consumption, oxygen consumption and heart rate
• increased sensitivity to sympathetic stimulation
• increased red blood cell formation
• increase bone turn over

Question 17

what happens when we don’t get enough iodine

Answer 17

• the follicles in the thyroid gland continue expanding with colloid, but none of the protein fluid gets converted to thyroid hormones so the neck looks hugely inflamed and swollen

Question 18

where are C-cells found?

Answer 18

between the follicles in the thyroid gland

Question 19

what is the purpose of c-cells

Answer 19

• to produce calcitonin hormones

Question 20

what does calcitonin do

Answer 20

• controls calcium levels for muscle contraction, by telling the body to store it in bones or remove it
• also stimulates the excretion of calcitonin from the body

Question 21

what is parathyroid hormone and the 3 main effects it has on the body

Answer 21

PTH works against calcitonin to keep calcium levels normal, putting calcium in the blood

• PTH acts on osteocytes to release calcium stored in bones
• PTH acts on kidneys to increase reabsorption of calcium
• PTH acts on the gut to increase calcium absorption

Question 22

where are the parathyroid glands found

Answer 22

• there are 4 and all found on the back of the thyroid

Question 23

what is the purpose if chief cells?

Answer 23

to produce PTH into the blood when blood calcium levels are low

Question 24

where are the adrenal glands found

Answer 24

• on top of the kidneys

Question 25

describe the structure of the adrenal glands

Answer 25

- inner Medulla - outer cortex which consists of 3 layers 1) most inner - zona reticularis 2) middle - zona fasciculata 3) outer- zona glomerulosa

Question 26

what functions do the cortex and medulla of the adrenal gland serve

Answer 26

- cortex produces steroid hormones | - medulla produces catecholamines (adrenaline and noradrenaline)

Question 27

which hormones are produced by each layer of the adrenal cortex

Answer 27

- reticularis, produces androgens (sex hormones) - fasciculata, produces glucocorticoids - glomerulosa, produces mineralocorticoids

Question 28

what effect do the hormones glucocorticoids and mineralocorticoids have

Answer 28

- glucocorticoids, promote glucose synthesis to maintain glucose levels also acts as anti-inflammatory - mineralocorticoids control electrolyte homeostasis

Question 29

what does the pineal gland do and how does it work?

Answer 29

- receives information from neurones in the visual pathway, and secretes the hormone melatonin when light levels are low

Question 30

what is the purpose of melatonin and which gland produces it

Answer 30

- to influence the circadian rhythm (sleep cycle) - it is also an antioxidant - produced by pinealocytes in the pineal gland

Question 31

describe the cellular structure of the pancreas

Answer 31

- the pancreas is an endocrine and exocrine gland - the endocrine tissues are called islets - islets contain 2 different types of cells alpha cells and beta cells

Question 32

what is the purpose of alpha cells

Answer 32

- to produce the hormone glucagon when blood glucose levels are low - glucagon stimulates the breakdown of glycogen and fats to make glucose

Question 33

what is the purpose of beta cells

Answer 33

- to produce insulin when blood glucose levels are high - insulin lowers blood glucose levels by letting glucose move into cells, breaking glucose down to make ATP, or by storing glucose as glycogen or fat

Question 34

what are the dangers of a high blood glucose level

Answer 34

- damage to blood vessels, the retina, peripheral nerves and increased risk of cardiovascular disease

Question 35

what is type 1 diabetes

Answer 35

- insulin dependent diabetes - pancreas doesn't produce enough insulin so injections are needed - 5-10% cases start in childhood

Question 36

what is type 2 diabetes

Answer 36

- non-insulin dependent diabetes - more common in older people especially with obesity - insulin is produced but the tissues don't respond to the hormone - to reduce symptoms exercise and diet

Question 37

which hormones are needed for growth

Answer 37

- insulin - growth hormones - thyroid hormones - parathyroid hormones - reproductive hormones

Question 38

what are the short term effects of the flight or fight response

Answer 38

- glucose reserves are broken down - increase in heart and respiratory rate - increase in energy uptake by cells

Question 39

what are the long term effects of the flight or fight response

Answer 39

- glucocorticoids break down fat and muscle to make glucose when glycogen runs out - low levels of potassium

Question 40

what happens in the extreme long term after a flight or fight response

Answer 40

- lipid resources run out - no electrolyte balance - organ failure