Endocrine System

Question 1

What are prostaglandins made from?

Answer 1

The fatty acid arachidonate

Question 2

Functions of prostaglandins

Answer 2

o Uterus – muscular contraction (period pains)
o Mediate effects of pyrogens (cause fevers)
o Memory & brain function.
o Increase blood flow in kidneys.
o Dilate small blood vessels – redness seen in inflammation.
o Protect stomach lining.
o Sensitise nerve endings that stimulate pain responses.
o Relax and contract lungs.

Question 3

What are some growth factors produced in the body?

Answer 3

granulocyte & macrophage colony stimulating factor, platelet derived growth factor, epidermal growth factor, nerve growth factor.

Question 4

What is leptin?

Answer 4

produced from adipose tissue – acts on hypothalamus to indicate satiety – obesity – genetic alteration of leptin – hypothalamic cells lack receptors.

Question 5

What hormone is produced by the heart?

Answer 5

atrial natriuretic hormone – antagonistic of aldosterone

Question 6

Describe the pineal gland?

Answer 6

brain – melatonin (regulates wake/sleep cycle)

Question 7

Describe the thymus?

Answer 7

lobular & lies beneath sternum – converts lymphocytes into T lymphocytes – cells produce thymosin (aid in lymphocyte differentiation)

Question 8

Describe the pancreas?

Answer 8

exocrine (digestive enzymes) & endocrine gland (insulin & glucagon - antagonistic)

Question 9

What are the 2 parts of the adrenal glands?

Answer 9

adrenal medulla & adrenal cortex

Question 10

Describe the adrenal glands?

Answer 10

sits above kidneys – hypothalamus controls.

Question 11

Describe the adrenal medulla?

Answer 11

cells derived from peripheral nervous system – sympathetic division of the autonomic nervous system controls involuntary response & adrenal medulla – tropic hormones don’t trigger these cells – produces adrenaline (epinephrine) – heart rate quickens, increased chemical reactions, glucose released from liver.

Question 12

Describe the adrenal cortex?

Answer 12

produces mineralocorticoids (regulate certain ions e.g. aldosterone), glucocorticoids (affect glucose metabolism – glucose broken down from non-carbohydrate substance), androgens (testosterone), progesterone, oestrogen

Question 13

Describe the parathyroid gland?

Answer 13

parathyroid hormone (works with calcitonin) maintains optimum Ca levels – stimulates osteoclasts, kidneys to reabsorb Ca, intestinal cells to absorb Ca from food – antagonistic to CT

Question 14

Describe the thyroid gland?

Answer 14

secretes T3 (triiodothyronine) & T4 (thyroxine) –controls metabolism – most body cells have receptors for thyroid hormones – cause effects of body – hyperthyroidism and hypothyroidism – calcitonin (decrease calcium levels)

Question 15

What hormones are produced by the posterior pituitary?

Answer 15

Antidiuretic hormone & oxytocin

Question 16

What is anti diuretic hormone?

Answer 16

control volume of blood – regulates water reabsorption in nephrons.

Question 17

What is oxytocin?

Answer 17

females during pregnancy – binds to target cells in uterus - causes contractions

Question 18

What hormones are described the anterior pituitary?

Answer 18

melanocyte stimulating hormone, prolactin, growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, gonadotropins (luteinising hormone and follicle stimulating hormone)

Question 19

What is prolactin?

Answer 19

acts with oestrogen & progesterone to stimulate the mammary gland (produce breast milk)

Question 20

What is melanocyte stimulating hormone?

Answer 20

acts on melanocytes – synthesise melanin pigment – epidermal cells in skin contain this pigment – genetically determine skin colour – UV stimulates MSH production, causes more melanin to be produced – protects against UV.

Question 21

What is growth hormone?

Answer 21

increase rate of growth of skeleton – simulate cartilage & bone cells to reproduce and lay down intercellular matrix

Question 22

What is thyroid stimulating hormone?

Answer 22

trigger T3 & T4 production (control growth, development & metabolism)

Question 23

What is adrenocorticotropic hormone?

Answer 23

triggers adrenal cortex to produce steroid hormones – cortisol (regulates glucose production from fats & proteins) & aldosterone ( regulate sodium & potassium ions) – hormones involved in male secondary sexual characteristics

Question 24

What is luteinising hormone?

Answer 24

male – stimulate testosterone production
females – stimulate release of egg, stimulates progesterone production

Question 25

What is follicle stimulating hormone?

Answer 25

females – maturation of an egg evry month, stimulates secretion of oestrogen males- triggers sperm production

Question 26

What are the gonads?

Answer 26

Sex glands - testes & ovaries

Question 27

What regulates the actions of the pituitary?

Answer 27

Hypothalamus

Question 28

In what way does the hypothalamus regulate the posterior pituitary?

Answer 28

Via nerve impulses

Question 29

In what way does the hypothalamus regulate the anterior pituitary?

Answer 29

By releasing hormones – travel via blood vessels.

Question 30

How many hormones does the pituitary produce?

Answer 30

9 7 from anterior - 5 stimulatory, 2 inhibitory 2 from posterior

Question 31

What is the hypothalamus?

Answer 31

mass of nerve cells – floor of brain connected to pituitary by stalk.

Question 32

Explain feedback loops

Answer 32

o Endocrine glands stimulated to synthesised & secrete hormones.  Direct – nervous  Indirect – nervous system releases hormones  Conc. of substance in blood o Hormone travels to target tissue via blood. o Desired effect occurs. o Feedback to endocrine gland - + more of hormone produced, - less hormone produced.

Question 33

Give an example of antagonistic hormones

Answer 33

insulin & glucagon o High sugar – insulin released by pancreas, cellular uptake of glucose, glycogen forms. o Low blood sugar – glucagon released by pancreas, glycogen broken down.

Question 34

What are the two type of hormones?

Answer 34

steroids & peptides

Question 35

What are hormones?

Answer 35

chemical messengers – produced at one site travels via blood stream to another site where it has an effect.

Question 36

What is a gland?

Answer 36

aggregation of cells specialized to secrete materials not related to their ordinary metabolic needs.

Question 37

What is an endocrine gland?

Answer 37

ductless – secreted into bloodstream.

Question 38

What is an exocrine gland?

Answer 38

secretes via ducts

Question 39

Function of endocrine system?

Answer 39

helps maintain homeostasis, responds to stress stimuli (with nervous system), regulate growth & development

Question 40

What is a neurosecretory cell?

Answer 40

specialised nerve cells – endocrine and neuron functions – conducts nerve impulses and secrete hormones

Question 41

What system works with the endocrine system to coordinate physiological processes?

Answer 41

nervous system

Question 42

What is the difference between a nerve response & hormonal response?

Answer 42

 Nerve cell exerts control in its immediate vicinity by releasing neurotransmitters at synapses affecting nerve cells, muscle cells, or glands.  Endocrine gland exerts widespread control by releasing hormones into bloodstream.

Question 43

What are the 4 functions of hormones?

Answer 43

regulation (control internal environment), response (change in external environment), reproductive, growth & development.

Question 44

How do hormones produced a desired effect?

Answer 44

 Hormones bind to receptor molecules embedded in membrane and located in cytoplasm – activates a chain of events – effect of the hormone is expressed.

Question 45

What are steroid hormones synthesised from?

Answer 45

cholesterol

Question 46

Which type of hormone can enter the cell?

Answer 46

steroid hormones

Question 47

Describe steroid hormones

Answer 47

Synthesised from cholesterol – pass through cell membrane – bind to nuclear/cytosolic steroid hormone receptors – change in cell.

Question 48

Describe peptide hormones

Answer 48

can’t enter cell, bind to receptors on outside and cause intracellular events or enzyme cascades.

Question 49

Name the 3 type of recpetors for peptide hormones

Answer 49

1. Single polypeptide chain with a domain on either side of the membrane, connected by a membrane-spanning domain e.g. epidermal growth factor 2. Single polypeptide chain that is passed back and forth in serpentine fashion across the membrane, - intracellular, transmembrane & extracellular domains e.g. beta-adrenergic (adrenaline) receptor 3. Multiple polypeptides e.g. insulin