The endocrine system

Question 1

Describe the general outline of a control system

Answer 1

1. stimulus
2. detected by receptor (chemo, thermo, proprioreceptors)
3. communicates with control center via afferent pathway (neuro or endocrine)
4. control centre determines set point, analyses input and coordinates response
5. communication via efferent pathway to effector
6. effector causes a change

Question 2

What is the bundle of neurones called that controls circadian rhythms?

Answer 2

The suprachiasmatic nucleus is the hypothalamus

Question 3

What does the suprachiasmatic nucleus respond to in order to control circadian rhythms?

Answer 3

• light
• temp
• social interaction
• exercise
• eating/ drinking pattern

Question 4

What hormone is involved in setting the body clock and where is it released form?

Answer 4

Melatonin released from pineal gland

Question 5

Give 3 examples of circadian rhythms

Answer 5

• body temp decrease at night
• cortisol spike in morning
• meltonin increase at night

Question 6

What is the difference between positive and negative feedback

Answer 6

Positive feedback is when stimulation results in a greater increase from baseline levels. Negative feedback is when stimulation results in a change to reverse back to baseline levels

Question 7

Give an example of negative and positive feedback

Answer 7

negative: control of blood glucose
positive: blood clotting, ovulation

Question 8

What is the difference between osmolarity and osmolality?

Answer 8

osmolarity is osmoles in a litre solution (volume)

osmolality is osmoles in a kg solution (mass)

Question 9

if something has high osmolarity does it have high or low solute concentrations?

Answer 9

high (eg lots of Na+)

Question 10

list the main endocrine organs

Answer 10

• pineal gland
• hypothalamus
• pituitary gland
• thyroid gland
• parathyroid gland
• thymus
• adrenal gland
• pancreas
• gonads

Question 11

Which classes of hormones are water and which are lipid soluble?

Answer 11

water soluble: peptide and glycoprotein

lipid soluble: amino acid derivatives and steroids

Question 12

Name some peptide hormones

Answer 12

insulin, glucagon, growth hormone

Question 13

Name some glycoprotein hormones

Answer 13

leutenising hormone
follicle stimulating hormone
thyroid stimulating hormone

Question 14

Name some amino acid derivative hormones

Answer 14

• catechoamines (adrenaline, noradrenaline)
• melatonin
• thyroid hormone

Question 15

name some steroid hromones

Answer 15

cortisol
aldosterone
testosterone

Question 16

What effect do carrier proteins have for hormones in blood?

Answer 16

• increase soluablity
• increase half life
• act as available reserve
• they cannot be used when bound to carrier protein only when free

Question 17

What receptors do water soluble hormones act on?

Answer 17

• GPCRs
• tyrosine kinase linked receptors
• ligand gated channels
• all on surface, usually activing kinases inside the cell

Question 18

What receptors do lipid soluble hormones act on?

Answer 18

• act on cytoplasmic receptors
• or nuclear receptors on hormone response elements to incease/ decrease transcription- therefor slower acting than water soluble hormones