Introduction to endocrine systems

Question 1

At what concentration is a hormone secreted?

Answer 1

low concentration

Question 2

Where is a hormone secreted from?

Answer 2

cell or group of cells

Question 3

How does is a hormone transported?

Answer 3

via bloodstream (circulatory system)

Question 4

Why does a hormone only act on specific cells?

Answer 4

Only acts on target cells because they have the correct, complementary membrane protein receptor (that is functional)

Question 5

Example of a disease where the receptors to a hormone are damaged?

Answer 5

type 2 diabetes

Question 6

significance of diastema

Answer 6

no contact points so interproximal caries is approached differently. Masticatory mucosa between teeth is non-keratinised so it will become keratinised.

Question 7

What determines how long a hormone persists?

Answer 7

clearance, half-life of hormone, absence of carrier, enzymes that breakdown hormone (e.g. in blood, liver)

Question 8

Examples of steroid hormones

Answer 8

cortisol, aldosterone, testosterone, oestrogen, progesterone

Question 8

What are steroid hormones based on?

Answer 8

cholesterol ring structure

Question 8

How can non-steroid hormones be divided?

Answer 8

amino acid derivatives, peptides, glycoproteins

Question 8

Examples of non-steroid hormones that are amines

Answer 8

adrenaline, noradrenaline, melatonin

Question 8

List of endocrine glands

Answer 8

hypothalamus, pituitary, thyroid, parathyroid, pancreas (islets), adrenal (supra-renal), GIT endocrine cells, gonads, placenta, pineal gland, thymus

Question 9

How can hormones be classified?

Answer 9

Steroid or non-steroid

Question 9

What are gonads?

Answer 9

ovaries and testes

Question 9

Two types of amino acid derivatives of non-steroid hormones

Answer 9

amines and iodinated amino acids

Question 10

Why is adrenaline considered both a neurotransmitter and hormone?

Answer 10

released into the bloodstream as well as in synapses

Question 11

Examples of iodinated amino acids that are non-steroid hormones

Answer 11

triiodothyronine, tetraiodothyronine (thyroxine)

Question 12

Examples of non-steroid peptide short chain hormones

Answer 12

antidiuretic hormone, oxytocin, melanocyte stimulating hormone, somatostatin, thyrotropin releasing hormone, gonadotropin releasing hormone, atrial natriuretic hormone

Question 13

Examples of non-steroid peptide long chain hormones

Answer 13

growth hormone, prolactin, PTH, calcitonin, adrenocorticotropic hormone, insulin, glucagon, GIT hormones (secretin, CCK, gastrin)

Question 14

Which types of hormones need to be modified? (not produced in their final form)

Answer 14

long chain peptide (non-steroid) hormones

Question 15

Name given to inactive precursor form of many peptide hormones

Answer 15

pro-hormone

Question 16

How are active hormones produced (from pre-prohormones)

Answer 16

the pre-prohormone is converted to pro-hormone in the endoplasmic reticulum. The prohormone is packaged in Golgi apparatus and converted to active hormone that is secrete from vesicles

Question 17

Example of a pro-hormone

Answer 17

proinsulin

Question 18

Why are some peptide hormones produced in an inactive form (e.g. proinsulin)

Answer 18

damage to the pancreas will release proinsulin instead of insulin. Proinsulin is not as effective so hypoglycaemia is avoided

Question 19

Why can hypoglycaemia be fatal?

Answer 19

Can starve the brain

Question 20

Which type of diabetic patients are more at risk of hypoglycaemia?

Answer 20

Type 1 diabetes - inject insulin without eating. Need to ensure timing of appointment suits patient's mealtimes

Question 21

Examples of glycoproteins (non-steroid) hormones

Answer 21

Follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone, chorionic gonadotrophin

Question 22

What is a glycoprotein?

Answer 22

A protein with carbohydrate groups attached to amino acids

Question 23

Examples of hormone-like substances that have a paracrine (local) effect

Answer 23

prostagrandins, leucotrienes, thromboxanes

Question 24

Functions of 'local tissue' hormones

Answer 24

blood flow regulation, homeostasis, mucosal protection (stomach), inflammation

Question 25

How do steroid hormones act?

Answer 25

Pass through the plasma membrane and bind to intracellular receptors

Question 26

How do non-steroid hormones act?

Answer 26

Via second messengers (non-steroid hormones cannot pass plasma membrane)

Question 27

Example of common second messengers

Answer 27

cAMP and Ca2+

Question 28

Overview of hormone action

Answer 28

1. Synthesis 2. storage 3. released in response to stimulus 4. transported in blood 5. act on target cells (2nd messengers) 6. metabolised and/or excreted

Question 29

Which organs have a role of removing hormones?

Answer 29

Kidneys (excrete), Liver (metabolise)

Question 30

How are most hormone systems regulated?

Answer 30

Negative feedback

Question 31

Example of negative feedback involving PTH

Answer 31

When there is a low plasma conc of Ca2+, PTH is secreted by the parathyroid glands. PTH acts on target cells which increases plasma Ca2+ conc

Question 32

Term used to describe excess secretion

Answer 32

hypersecretion

Question 33

Term used to describe decreased secretion

Answer 33

hyposecretion

Question 34

What feature can alter the sensitivity of target cells?

Answer 34

The number of membrane receptors

Question 35

Term used to describe a cell that has an increased number of receptors

Answer 35

upregulation

Question 36

Term used to describe a cell that has decreased number of receptors

Answer 36

downregulation

Question 37

Effect of upregulation

Answer 37

do not need much hormone to cause the same response

Question 38

effect of downregulation

Answer 38

need more hormone to cause the same response

Question 39

Effect of having a prolonged high concentration of cortisol

Answer 39

leads to downregulation of cortisol receptors therefore a higher concentration of cortisol is required to cause the same response

Question 40

Examples of medications that can cause downregulation of cortisol receptors

Answer 40

corticosteroids, corticotherapy

Question 41

3 potential causes of hyperfunction

Answer 41

excess production/secretion, upregulation of receptors, failure to metabolise hormone (clearance)

Question 42

3 potential causes of hypofunction

Answer 42

decreased production/secretion, downregulation of receptors, non-functioning receptors (e.g. type 2 diabetes which leads to hypersecretion of insulin so B cells are overloaded)