introduction to endocrine systems

Question 1

How is endocrine transmission carried?

Answer 1

Via blood stream
Chemical secreted
Low concentration
By a cell or group of cells
Sent to all parts of body
Hormone acts only in cells with correct membrane receptor protein (target cells)

Question 2

what are characteristics of humoral communication (by hormones)?

Answer 2

• many cells in different parts of body
• coordinated, body-wide actions
• slow to act
• effect persists

Question 3

give examples of endocrine glands?

Answer 3

Hypothalamus
Pituitary
Thyroid
Parathyroid
Pancreas (Islets)
Adrenal (supra-renal)
GI tract endocrine cells
Gonads (ovaries and testes)
Placenta
Pineal gland
Thymus

Question 4

what are the examples of non-steroid hormones?

Answer 4

Amino acid derivatives
Peptides
Glycoproteins

Question 5

what are examples of steroid hormones?

Answer 5

based on cholesterol ring structure:
Cortisol
Aldosterone
Testosterone
Oestrogen
Progesterone

Question 6

what are examples of amine amino acid derivative non-steroid hormones?

Answer 6

Adrenaline (epinephrine)
Noradrenaline (norepinephrine)
Melatonin

Question 7

what are examples of iodinated amino acid derivative hormones?

Answer 7

Triiodothyronine
Tetraiodothyronine (thyroxine)

Question 8

what are examples of short chain peptide non-steroid hormones?

Answer 8

Antidiuretic hormone
Oxytocin
Melanocyte stimulating hormone
Somatostatin
Thyrotropin releasing hormone
Gonadotropin releasing hormone
Atrial natriuretic hormone

Question 9

what are examples of long chain (protein) peptide non-steroid hormones?

Answer 9

Growth hormone
Prolactin
Parathyroid hormone
Calcitonin
Adrenocorticotropic hormone
Insulin
Glucagon
GI tract hormones (secretin, CCK, gastrin)

Question 10

what is the case with many peptide hormones?

Answer 10

• produced in the inactive precursor form
• pre-prohormone converted to prohormone in the ER
• prohormone packages in Golgi apparatus and converted to active hormone
• active hormone is secreted by vesicles

Question 11

what are examples of glycoprotein non-steroid hormones?

Answer 11

proteins with attached carbohydrate groups to amino acids
- Follicle stimulating hormone
- Luteinizing hormone
- Thyroid stimulating hormone
- Chorionic gonadotrophin

Question 12

what are examples of local tissue hormones with paracrine effect?

Answer 12

• Prostagrandins
• Leucotrienes
• Thromboxanes

Question 13

what are the functions of paracrine local tissue hormones?

Answer 13

Blood flow regulation
Haemostasis
Mucosal protection (stomach)
Inflammation

Question 14

which type of hormone can pass into the cell?

Answer 14

steroid

Question 15

what are common second messangers?

Answer 15

cAMP and Ca++

Question 16

summarise hormone action

Answer 16

Synthesis and storage
Release in response to stimulus
Transport in blood
Action on target cells (role of 2nd messengers)
Metabolism and/or excretion

Question 17

what are most hormone systems regulated by?

Answer 17

negative feedback

Question 18

what is hypersecretion?

Answer 18

excess secretion

Question 19

what is hyposecretion?

Answer 19

decreased secretion

Question 20

what varies the sensitivity of target cells?

Answer 20

number of membrane receptors

Question 21

what is upregulation caused by?

Answer 21

more receptors

Question 22

what is downregulation caused by?

Answer 22

fewer receptors

Question 23

describe hyperfunction

Answer 23

Excess production & secretion
Upregulation of receptors
Failure to metabolise hormone

Question 24

describe hypofunction

Answer 24

Decreased production & secretion
Downregulation of receptors
Receptors non functioning