Introduction to the endocrine system S6L2

Question 1

What are the 4 main components of a control system?

Answer 1

1) stimulus
2) receptor to detect stimulus
- communication via afferent pathways
3) control centre
- communication via efferent pathways
4) effector

Question 2

Define negative feedback

Answer 2

In neg feedback the output inhibits the function of the control centre and the effector acts to oppose the stimulus.

Question 3

Does insulin decrease or increase the level of glucose in the blood?

Answer 3

decrease

Question 4

Can positive feedback cause rapid, catastrophic change?

Answer 4

yep

Question 5

Give two examples of positive feedback

Answer 5

Blood clotting, ovulation (build up of FSH causes release of oocyte)

Question 6

The set point of a control centre can change. In case of cortisol, when does it peak and trough?

Answer 6

Peak: 7am
Trough: 7pm

Question 7

What hormone is involved in setting the body’s biological clock?

Answer 7

Melatonin released from the pineal gland

Question 8

Define osmolarity and osmolality

Answer 8

Osmolarity: the number of osmoles per litre of solution
Osmolality: the number of osmoles per Kg of solution

Question 9

What receptors in the hypothalamus detect osmolality?

Answer 9

Osmoreceptors

Question 10

If there is a high blood osmolality, what hormone is released from the posterior pituitary gland?

Answer 10

Anti diuretic hormone (ADH) also known as vasopressin

Question 11

What effect does ADH have on the kidney?

Answer 11

Increases reabsorption of water from the urine into the blood

Question 12

Are hormones present in the blood in high or low concentrations?

Answer 12

Very low

Question 13

What are the 4 main classifications of hormones?

Answer 13

1) petptide/polypeptide (largest group)
2) glycoproteins
3) amino acid derivatives
4) steroids

Question 14

Give some examples of peptide/polypeptide hormones

Answer 14

Insulin, glucagon, growth hormone

Question 15

Examples of amino acid derivative hormones..

Answer 15

adrenaline, noradren, thyroid hormones

Question 16

What are steroids all derived from?

Answer 16

cholesterol

Question 17

Examples of steroid hormones..

Answer 17

cortisol, aldosterone, testosterone, oestrogen

Question 18

Are steroid hormones and thyroid hormones hydrophobic or hydrophilic?

Answer 18

hydrophobic

Question 19

Thyroid hormones bind specifically to what protein in the blood?

Answer 19

Thyroxine Binding Globulin (TBG), some is also bound nonspecifically to other proteins such as albumin

Question 20

In many cases the secretion of one hormone is controlled by another. The second hormone is known as what?

Answer 20

a tropic hormone

Question 21

Releasing and Inhibiting hormones travel to the pituitary gland via what vessels?

Answer 21

hypophyseal portal vessels

Question 22

Lipophilic hormones bind to receptors inside cell. True or false?

Answer 22

True

Question 23

Where is the appetite centre located?

Answer 23

The arcuate nucleus in the hypothalamus

Question 24

What can the primary neurones in the arcuate nucleus be divided into?

Answer 24

excitatory and inhibitory types

Question 25

The excitatory neurones stimulate appetite via the release of what?

Answer 25

neuropeptide and agouti-related peptide (AgPR)

Question 26

The inhibitory neurones suppress appetite via what?

Answer 26

POMC

Question 27

Does Ghrelin stimulate or suppress appetite?

Answer 27

stimulate

Question 28

Leptin, released from adipocytes, suppresses appetite. True or false?

Answer 28

True