Introduction into Neuroendocrinology

Question 1

What was the first named hormone ?

Answer 1

• Secretin
• Stimulates the exocrine pancreas to secrete bicarbonate into the bowels to neutralise the acid

Question 2

How is homeostasis defined ?

Answer 2

Homeostasis is the striving of an organism to maintain a steady state.

Question 3

Name three milestones of discovery in endocrinology.

Answer 3

1. 1901 - Discovery of adrenaline by Takamine
2. 1902 - Discovery of secretin by Starling and Bayliss
3. 1916 - Discovery of thyroxine by Kendall

Question 4

How are hormones defined ?

Answer 4

Hormones are highly potent specialised organic molecules which control biological functions by interacting with specific receptors on/in responsive cells.

Question 5

What are the components of an endocrine system ?

Answer 5

1. Production site
   -> Synthesis and release of hormones
2. Transport system

3a. Target cell
-> Receptor activation
-> Hormone inactivation and excretion

3b. Other tissues
-> Hormone inactivation and excretion

Question 6

Name the two types of hormonal functions.

Answer 6

1. Homeostatic control
   -> e.g. permanent uptake and release of carbohydrates, proteins, fatty acids and electrolytes
2. Morphogenetic actions
   -> e.g. control of changes during growth and development

Question 7

Name four examples for homone actions.

Answer 7

1. Control of enzyme activity
2. Control of gene expression
3. Regulation of transport across membranes
4. Control of the secretion of other hormones

Question 8

Name the three classes of hormones in human.

Answer 8

1. Protein- and peptide hormones
2. Aminoacid derivates
3. Steroids

Question 9

What are neurotransmitters ?

Answer 9

• Small molecules synthesized in neurons
• localized in presynapsis
• release triggered by neuranal activity
• act at specific receptors

Question 10

Name two differences between hormones and neurotransmitters.

Answer 10

• Hormones are synthesized in endocrine cells while neurotransmitters are synthesized in neurons
• Neurotransmitters act faster than hormones

Question 12

What is neuroendocrine action ?

Answer 12

Release of peptide hormones into the blood by neurons

Question 13

What does it mean, if neurons have endocrine actions ?

Answer 13

• Neurons can release peptide hormones
• In this case the peptide hormones are also neurotransmitters, if the release goes not into the blood but in another neuron

Question 14

Name three classical neurotransmitters / types of neurotransmitters.

Answer 14

1. Acetylcholin
2. Aminoacids
3. Monoamines
   
   • Noadrenaline
   • Adrenaline
   • Dopamine
   • Serotonine

Question 15

Name three peptide neurotransmitters / types of peptide neurotransmitters.

Answer 15

1. Neuropeptide Y (NPY)
2. Opiods
3. Hypothalamic releasing hormones

Question 16

How are peptide neurotransmitters also called ?

Answer 16

Neuropeptides

Question 17

How are neurology and endocrinology connected ?

Answer 17

• Many physiological processes are controlled by both nervous and endocrine system
• Interactions of both systems serve to coordinate them
• Occasionally, the same substances are involved in both systems

Question 18

How were neurohormones described in the first place ?

Answer 18

• Chemical messengers which were secreted from neurons into the blood
• Discovered by Berta and Ernst Scharrer in the 1930ies

Question 19

Describe the functional connection of the hypothalamus and the pituitary.

Answer 19

• The nerve endings of the hypothalamic neurons secrete neurohormones near capillaries that give rise to portal vessels
• The neurohormones from the portal vessels regulate the release of hormones from the pituitary cells into the blood

Question 20

What is the function of the portal system between the hypothalamus and the pituitary ?

Answer 20

• In this portal system the venes spread out to capillaries close to the nerve endings of the hypothalamic neurons
• The hormones released by the neurons can bypass the blood-brain barrier quickly and efficiently