Endocrine system

Question 1

What are the two control centres and what do they control

Answer 1

Hypothalamus - endocrine system

Medulla oblongata - ventilation and cardiovascular system

Question 2

Where is the biological clock located in the body

Answer 2

Suprachiasmatic nucleus in hypothalamus

Question 3

What happens in a biological rhythm

Answer 3

Where the set point for a haemostatic value varies over time

Question 4

What is involved in setting the biological clock and where does the signal come form

Answer 4

Melatonin released by the pineal gland

Question 5

What receptors monitor osmolality and sodium ion concentration and where are they found

Answer 5

Osmoreceptors in the supraoptic and paraventricular nuclei of hypothalamus

Question 6

What is the normal plasma osmolality range

Answer 6

275-295mOsmol/kg

Question 7

What hormone is released by the posterior pituitary gland if the plasma osmolaltiy is high and what does it do

Answer 7

Anti-diuretic hormone

Increases permeability of collecting ducts to water, increasing water reabsorption

Question 8

What are the types of hormones and define if they are water or lipid soluble

Answer 8

Peptide/polypeptide - water soluble

Glycoprotein - water soluble

Amino acid derivatives (amines) - adrenal medulla: water soluble, thyroid: lipid soluble

Steroid - lipid soluble

Question 9

How are polypeptide hormones and catecholamines stored

Answer 9

Stored as hormones in storage vesicles

Question 10

How are steroid hormones stored

Answer 10

As lipid precursor as cholesterol esters

Question 11

How does the thyroid gland store its hormones

Answer 11

Hormones are stored outside the cell as protein colloid

Question 12

What processes determine hormone levels

Answer 12

Rate of production

Rate of delivery

Rate of degradation

Question 13

What are the two names of hormones where secretion of one hormone is controlled by secretion of the other and what do they do

Answer 13

Tropic - have another endocrine gland as their target

Trophic - stimulate growth/effect in target tissue

Question 14

What type of hormone is mainly secreted by the anterior pituitary gland and what are the names of the hormones secreted by the anterior pituitary

Answer 14

Tropic hormones

Thyroid stimulating hormone = thyrotropin (TSH)

Adrenocorticotropin hormone = corticotropin (ACTH)

Growth hormone = somatotropin (GH)

Luteinizing hormone (LH)

Follicle stimulating hormone (FSH)

Prolactin

Question 15

What hormones affect release of other hormones and where are they produced and where do they act

Answer 15

Releasing and Inhibiting hormones

From nerve cells in the hypothalamus

Act on the anterior pituitary glands

Question 16

Where are hormones inactivated and how are protein and steroid hormones inactivated

Answer 16

Inactivated mainly in liver and kidney but can occur in target tissue

Steroid inactivated by changing water solubilty allowing them to be excreted from body in urine or bile

Protein hormones inactivated by degradation to amino acids

Question 17

How might disorders of the endocrine system be caused

Answer 17

Changes in endocrine tissue causing over/under secretion or secretion of abnormal and less effective hormones

Responsiveness of endocrine tissues altered by presence of abnormal proteins

Effective concentration of hormone reduced due to binding to circulating hormones

Changes in responsiveness of target tissues to hormones due to receptor and/or post-receptor changes

Question 18

What are the two types of lipophilic receptors and how do they differ

Answer 18

Type I - binds hormone in cytoplasm before entering nucleus

Type II - enters nucleus and then binds to receptor