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Flashcards in Pharmacology Deck (45)
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1

Describe the difference between the endocrine and exocrine systems

Endocrine - hormones secreted into Extra-cellular fluid

Exocrine - secretes hormones into duct system which then empties hormones into various parts of body

2

Name the main endocrine glands in the body

Pineal gland
Hypothalamus
Pituitary

Thyroid
Parathyroid
Thymus

Adrenal Glands
Pancreas

Ovaries
Testes

3

Name the four main chemical groupings of hormones

Modified Amino Acids
Steroid
Peptide
Protein

4

What substance is the precursor for steroid hormones?

Cholesterol

5

Adrenaline, T3 and T4 are examples of what type of hormone?

Modified amino acids

6

Give examples of steroid hormones

Cortisol
Progesterone
Testosterone

7

Adrenocorticotrophic hormone (ACTH) and anti-diuretic hormone are members of what group of hormones?

Peptides

8

Give one example of a protein hormone

Insulin

9

Describe the difference between Autocrine, Paracrine and Endocrine

Autocrine - cell that releases the signal also receives the signal

Paracrine - cell that sends the signal is adjacent to the cell which recieves the signal

Endocrine - cell sends signal into bloodstream and signal is recieved at an organ distal to the original cell site

10

It is possible for hormones to act in more than one manner (e.g. both paracrine and endocrine). TRUE/FALSE?

TRUE

e.g. somatostatin = paracrine in pancreas
BUT endocrine in brain

11

Hormones act at very high concentrations. TRUE/FALSE?

FALSE

Act at very low concentrations
=> act with very high potency

12

What occurs when a hormone binds to its target receptor?

- biological response is triggered
- signal transduction cascade
- causes amplification of the original signal

13

How is hormone action terminated?

- enzyme-mediated metabolic inactivation in the liver
- or terminated at sites of action

14

Give an example of hormones which work together in a complementary manner

Adrenaline, cortisol, glucagon

Prevent hypoglycaemia and hypokalaemia in short term intense exercise

15

What hormones work in an antagonistic manner?

INSULIN and GLUCAGON

Insulin:
- lowers plasma glucose levels

Glucagon:
- increases plasma glucose levels

=> opposite effects

16

How are amine hormones released from cells?

- pre-synthesised
- stored in vesicles
- released by Ca2+ dependent exocytosis

17

Are amine hormones hydrophilic or hydrophobic? Can they be transported freely in plasma?

Amines are hydrophilic
=> transported mainly free in plasma

18

Are peptide hormones hydrophilic or hydrophobic? Can they be transported freely in blood plasma?

hydrophilic
=> transported mainly free in plasma

19

How are peptide hormones released from cells?

- pre-synthesised usually longer precursors
- stored in vesicles
- released by Ca2+-dependent exocytosis

20

How are steroid hormones synthesised and released from cells?

- synthesised and secreted upon demand

21

How do stimuli increase the production/secretion of steroid hormones?

Stimuli increase:
(i) cellular uptake and availability of cholesterol
(ii) rate of conversion of cholesterol to pregnenolone (rate limiting step)

22

Are steroid hydrophilic or hydrophobic?

- hydrophobic
=> transported in plasma mainly bound (~90%) to plasma proteins

**only ‘free’ steroid hormone is biologically active**

23

What are the main functions of carrier proteins?

- increase amount transported in blood
- provide a reservoir of hormone
- extend half-life of the hormone in the circulation

24

Give examples of specific carrier proteins

cortisol-binding globulin (CBG) – binds cortisol in a selective manner (also some aldosterone)

thyroxine-binding globulin (TBG) – binds thyroxine (T4) selectively [also some triiodothyronine (T3)]

sex steroid-binding globulin (SSBG) – binds mainly testosterone and oestradiol

25

Give an example of a general carrier protein

albumin – binds many steroids and thyroxine

26

Why do peptide and protein hormones not last as long?

They do not have carrier proteins to prolong their half life

27

How do carrier proteins prevent surges in hormone?

bind free hormone to buffer surge in concentration

28

If hormone is eliminated from the plasma, what is the role of carrier proteins?

To dissociate from hormone and create more "free" to enter plasma and maintain concentration

29

What elements of the HPA axis can cortisol negatively feedback on?

Hypothalamus
Anterior Pituitary

30

What external factor can have a positive effect on the HPA pathway, causing it to be stimulated more?

Stress at level of hypothalamus
elicits sudden burst in secretion