Week 5 - Endocrine System

Question 1

How do cells communicate?

Answer 1

• Gap junctions
• Diffusion into cells from local interstitial fluid (paracrine secretions)
• Greater distances require the nervous and endocrine system

Question 2

What is the Endocrine System?

Answer 2

• Endo - Within
• Crine - Secrete
• Ductless, releases hormones (chemical signals) directly into blood
• Surrounded by fenestrated capillaries to take up hormone
• Hormones randomly leave blood and enter tissue fluid cells

Question 3

How is the Endocrine System different to the Nervous System?

Answer 3

• Effects slower to start and stop, longer lasting and more widespread
• Endocrine and nervous system continually regulate each other as they have a common goal (maintain homeostasis)
• Some chemicals function as a neurotransmitter and a hormone

Question 4

What are the three chemical groups of hormones?

Answer 4

• Steroid hormones
• Monoamines
• Peptide hormones

Question 5

What are Steroid hormones?

Answer 5

• Synthesised from cholesterol (4 carbon rings)
• Differ by attached functional groups

Question 6

What are Prostaglandins?

Answer 6

• Derived from a fatty acid (phospholipids)
• Act locally (paracrine)
• Released from plasma membranes
• Diverse roles e.g fever and pain (nocireceptors)

Question 7

What are Monoamines?

Answer 7

• Small, synthesised from amino acids (tyrosine or tryptophan)
• Thyroid hormone
• Adrenaline (epinephrine)
• Melatonin

Question 8

What are Hormones?

Answer 8

• Bind to a receptor of a target cells
• Receptor is a protein or glycoprotein
• Target cells possess the correct receptor that can bind and read the hormonal message

Question 8

What are Peptide hormone?

Answer 8

• Chain of amino acids (peptides, glycoproteins or proteins)
• Largest class e.g ADH and insulin

Question 9

What are Receptors?

Question 10

What is Hormone-Receptor binding?