Introduction to endocrine system

Question 1

What are the two major control systems of the vertebrate body

Answer 1

Endocrine System

Nervous System

Question 2

What does the endocrine system regulate

Answer 2

Growth
Development
Reproduction
Senescene

Question 3

What is the definition of a hormone

Answer 3

A chemical messenger produced and secreted by a specialised endocrine gland that is transported in the blood stream to a distant target organ/cell where it elicits a physiological response

Question 4

Give examples of endocrine systems

Answer 4

Hypothalamus
Posterior and anterior pituitary 
Thyroid
Heart
Liver 
Stomach and small intestine
Pancreas
Kidney 
Skin

Question 5

What are the three classes of hormone and give an example for each

Answer 5

1. Proteins and peptides:
   Growth hormone
2. Cholesterol derivatives:
   Steroids
   Vitamin D
   Steroid hormones: glucocorticoids, aldosterone
3. Modified Amino acids:
   Structure changes to become amino acid
   Adrenaline- hydrophilic
   THYROID hormones- hydrophobic

Question 6

What does hormone action affect

Answer 6

growth
Development
Metabolic activity
Tissue function

Question 7

What are circulating hormones influenced by

Answer 7

Rate of secretion

Rate of metabolism

Serum binding proteins

Question 8

How is hormone secretion regulated by physiological changes in blood glucose, stress and blood calcium

Answer 8

Blood glucose- regulates insulin and glucagon release from pancreas

Stress: adrenaline release from adrenal medulla

Blood calcium: regulates parathyroid hormone from parathyroids

Question 9

How is hormone secretion regulated by endogenous rhythms like ultradian, circadian, infradian

Answer 9

Ultradian- cycles every so minutes (GnRH pulses)

Circadian- daily cycles (testosterone and cortisol every 24 hours)

Infradian- monthly cycles (LH in females- 28 day period)

Question 10

What is a negative and positive feedback loop

Answer 10

Negative- maintains homeostasis via a loop to the gland the hormone came from

Positive- stimulates more hormone production
Example: Pre-ovulatory LH surge

Question 11

What is ectopic hormone secretion and give an example

Answer 11

Hormone made outside of normal endocrine gland such as a tumour

Question 12

What is addisons disease

Answer 12

Destruction of adrenal cortex

Question 13

What can a lack of in diet cause hyposecretion

Answer 13

Lack of Iodine deficiency

Question 14

What is Laron syndrome

Answer 14

GH receptor mutation that leads to raised/normal Growth hormone levels