Introduction to the Endocrine System

Question 1

What are the major endocrine glands?

Answer 1

→ Hypothalamus
→ Pituitary
→ Thyroid
→ Adrenal cortex
→ Gonads
→ Pancreas
→ Parathyroid glands

Question 2

What is the function of the hypothalamus?

Answer 2

→ Releases and inhibits hormones

Question 3

What are the two lobes of the pituitary and what hormones do they secrete?

Answer 3

→ Anterior - trophic hormones (growth)

→ Posterior - oxytocin & vasopressin

Question 4

What hormones does the thyroid secrete?

Answer 4

→ Thyroxine T4

→ tri-iodothyronine T3

Question 5

What are the two parts of the adrenal gland and what do they secrete?

Answer 5

→ Cortex - cortisol + aldosterone

→ Medulla - adrenaline/noradrenaline

Question 6

What hormones do the gonads produce?

Answer 6

→ Estrogens
→ Androgens
→ Progestagens

Question 7

What hormones does the pancreas secrete?

Answer 7

→ Insulin

→ Glucagon

Question 8

What hormone does the parathyroid gland release?

Answer 8

→ Parathyroid hormone

Question 9

What are other hormones that are important?

Answer 9

→ EPO + vit. D (hormone)
→ ANP, endothelins (CVS)
→ Melatonin (Pineal gland)
→ Thymic hormones (thymus)
→ phosphate (bones)
→ Leptin (adipose tissue)

Question 10

What is endocrine signalling?

Answer 10

→ hormones released into circulation and acting on distant target sites

Question 11

What is paracrine signalling?

Answer 11

→ Hormones released by endocrine cells that act locally on adjacent cells

Question 12

What is autocrine signalling?

Answer 12

→ Hormones released by a cell which acts on itself

Question 13

What is intracrine signalling?

Answer 13

→ Conversion of an inactive hormones to an active hormone that acts within that cell

Question 14

What are the three general functions of hormones?

Answer 14

→ Reproduction, growth and development
→ Maintenance of internal environment
→ Energy production, utilization and storage

Question 15

What are the hormones involved in reproduction, growth and development?

Answer 15

→ Sex steroids, thyroid hormones, prolactin, growth hormone

Question 16

What are the hormones involved in maintenance of the internal environment?

Answer 16

→ Aldosterone
→ Parathyroid hormone
→ Vit. D

Question 17

What are the hormones involved in energy production, utilization and storage?

Answer 17

→ Insulin
→ Glucagon
→ Thyroid hormones
→ Cortisol
→ Growth hormone

Question 18

What are protein/peptide hormones?

Answer 18

→ hypothalamic
→ pituitary
→ Insulin, PTH, calcitonin

Question 19

What are steroid (cholesterol) hormones?

Answer 19

→ Cortisol
→ Aldosterone

→ estrogens
→ Androgens
→ Progestagens

→ Vit. D

Question 20

What are amino acid derivatives ( tyrosine/tryptophan) hormones?

Answer 20

→Adrenaline
→ Noradrenaline
→ Thyroid hormones
→ Melatonin

Question 21

WHat are fatty acid derivative hormones?

Answer 21

→ Prostaglandins
→ Thromboxanes
→ Prostacyclins

Question 22

What are protein and peptide hormones secreted as?

Answer 22

→ Prohormones

Question 23

Why are there similarities within peptide hormones?

Answer 23

→ Common ancestral gene

Question 24

How is cholesterol formed?

Answer 24

→ Steroid nucleus

→ Carbon 20 the molecule gets cleaved and the backbone form

Question 25

What is the half life of protein and peptide hormones and how are they transported?

Answer 25

→ HL : minutes | → Transport : unbound

Question 26

What is the half life of tyrosine derivatives and how are they transported?

Answer 26

→ HL: Seconds - Hours The iodination affects the half life and solubility- thyroid hormones so their t1/2 is hours → Transport : Thyroid hormones are bound to plasma proteins

Question 27

What is the half life of cholesterol derivatives and how are they transported?

Answer 27

→ HL: Hours- days | → Transport : Bound to plasma proteins

Question 28

What is the neuroendocrine integration?

Answer 28

→ Nerves → Hormones → Effector organs

Question 29

Describe the hypothalamic -pituitary axis?

Answer 29

→ Hypothalamus - releases neurohormones → Goes to pituitary gland → Pituitary gland releases TSH, FSH, ACTH →Stimulates the endocrine organs

Question 30

What does corticotrophin releasing hormone (CRH) stimulate?

Answer 30

→ Released from hypothalamus | → acts to increase adrenocorticotrophic hormone (ACTH) in the anterior pituitary

Question 31

What does thyroid releasing hormone stimulate?

Answer 31

→ TRH increases TSH in anterior pituitary

Question 32

What does GnRH stimulate and where?

Answer 32

→ GnRH from the hypothalamus (gonadotrophin releasing hormone) increases LH and FSH in anterior pituitary

Question 33

What does dopamine inhibit and where?

Answer 33

→ Dopamine from hypothalamus decreases prolactin in anterior pituitary

Question 34

What does GHRH stimulate and where?

Answer 34

→ GHRH from hypothalamus (growth hormone releasing hormone) stimulates GH in anterior pituitary

Question 35

What does GHIH inhibit and where?

Answer 35

→ GHIH from hypothalamus ( growth hormone inhibiting hormone) inhibits GH in anterior pituitary

Question 36

How does feedback control of hormone synthesis work?

Answer 36

→ Negative feedback

Question 37

How are hormones released?

Answer 37

``` → Pulsatile release → Circadian → Diurnal → Monthly → Annual ```

Question 38

What hormone rises when you sleep?

Answer 38

→ Growth hormone

Question 39

What hormone is independent of the diurnal variation?

Answer 39

→ Cortisol

Question 40

What are the 4 disorders of the endocrine system?

Answer 40

→ Excess or deficiency → Impaired synthesis → Transport and metabolism of hormones → Resistance to hormone action

Question 41

What is excess growth hormone called?

Answer 41

→ Acromegaly | Prominent features

Question 42

What are other diseases that are regulated by cortisol?

Answer 42

→ Addisons - lack | → Cushings - excess

Question 43

What does cortisol regulate in the body?

Answer 43

→ Gluconeogenesis → Protein mobilization → Fat mobilization → Anti-inflammatory effects

Question 44

What is complete resistance to circulating androgens called?

Answer 44

→ Testicular feminization

Question 45

What is vitamin D resistance called?

Answer 45

→ Rickets

Question 46

What are magnocellular cells?

Answer 46

in the hypothalamus synthesise and release posterior pituitary hormones

Question 47

What is the difference between the anterior and posterior pituitary gland?

Answer 47

→ Neuroendocrine neurons in the hypothalamus project axons to the median eminence, at the base of the brain. → these neurons can release substances into the small blood vessels that travel directly to the anterior pituitary gland (the hypothalamo-hypophysial portal vessels).​ → The posterior pituitary consists mainly of neuronal projections ( axons ) extending from the supraoptic and paraventricular nuclei of the hypothalamus. → These axons release peptide hormones into the capillaries of the hypophyseal circulation. ​