Neuro-endocrinology

Question 1

What is neuroendocrinology?

Answer 1

A branch of life sciences dealing with neurosecretion and the physiological interaction between the CNS and endocrine system

Question 2

What are the basic components of the neuroendocrine system?

Answer 2

Parvocellular neurones and Magnocellular neurones in the hypothalamus act on the anterior and posterior pituitary in the pituitary gland, which act on target tissue, adrenal glands, thyroid gland and the gonads.

Question 3

What is the function of the hypothalamus in neuroendocrinology?

Answer 3

To integrate autonomic responses and endocrine function with behaviour

Question 4

Give 3 ways the hypothalamus controls homeostasis

Answer 4

Behaviour concerned with everyday homeostatic requirements of life Neuronal control through the autonomic nervous system Hormonal control through hormone release from the pituitary gland

Question 5

What are the six homeostatic functions controlled by the hypothalamus and how is this achieved?

Answer 5

1) Blood pressure and electrolyte composition 2) Body temperature 3) Energy metabolism 4) Reproduction 5) Stress response 6) Growth 1) Control of drinking salt appetite and control of blood osmolarity and vasomotor tone 2) Metabolic thermoregulation and behaviours like seeing an appropriate environment 3) Feeding, digestion and metabolic rate 4) Hormonal control of mating, pregnancy, lactation 5) Adrenal stress hormones 6) Growth hormone

Question 6

Which hypothalamic nuclei is responsible for: Stress Energy balance Osmoregulation Maternal Control Blood pressure

Answer 6

Paraventricular nucleus

Question 7

Which hypothalamic nuclei is responsible for: Osmoregulation Maternal control

Answer 7

Supraoptic nucleus

Question 8

Which hypothalamic nuclei is responsible for: Reproduction Growth Lactation

Answer 8

Arcuate nucleus

Question 9

What is associated with a loss of Hypothalamic Orexin Neurones?

Answer 9

Narcolepsy

Question 10

Where is the pituitary gland located?

Answer 10

In a bony cavity at the base of the brain called the Sella Turcica

Question 11

How is the pituitary gland connected to the hypothalamus?

Answer 11

Via the pituitary stalk

Question 12

Respectively, where do the anterior and posterior pituitary glands develop from?

Answer 12

A = Pharyngeal Epithelium P = Neuronal

Question 13

Respectively, what cells do the anterior and posterior pituitary glands contain?

Answer 13

A = Glandular cells P = Axon terminals

Question 14

Respectively, which neurons act on the anterior and posterior pituitary glands?

Answer 14

A = Parvocellular neurons P = Magnocellular neurons

Question 15

Respectively, what is the neuroendocrinological action of the anterior and posterior pituitary gland?

Answer 15

A = Releasing/inhibiting factors via hypophysial portal system P = Hormones directly released from magnocellular axons

Question 16

Which hormone is responsible for long bone growth?

Answer 16

Growth hormone

Question 17

Which hormone is responsible for Thyroid stimulation and regulation? (T3 and T4 release)

Answer 17

Thyroid stimulating hormone

Question 18

Which hormone is responsible for stimulation of the adrenal cortex? What is released on stimulation?

Answer 18

ACTH Corticosteroids

Question 19

Which hormones are responsible for stimulation of the ovaries and testies? What is released on stimulation?

Answer 19

FSH and LH Oestrogen and progesterone are released by the ovaries Testosterone is released by the testis

Question 20

What hormone is responsible for milk production in lactating women?

Answer 20

Prolactin

Question 21

What does the hormone oxytocin do? Where is it released from?

Answer 21

Milk letdown in lactating women and uterine contractions in pregnant women Released from the posterior pituitary gland

Question 22

What does the hormone ADH do? Where is it released from?

Answer 22

Kidney water retention Posterior pituitary gland

Question 23

What is the feedback mechanism of prolactin?

Answer 23

Prolactin secretion causes the Parvocellular neurons in the anterior pituitary gland to reduce dopamine secretion, which in turn causes increased prolactin secretion and therfore more milk production Dopamine secretion and therefore milk production can also be regulated by a suckling stimulus

Question 24

Describe the HPT axis (Hypothalamic-pituitary-thyroid axis) feedback loop What type of feedback loop is this?

Answer 24

Hypothalamus senses low levels of T3/T4 and responds by releasing TRH (thyrotropin-releasing hormone). TRH stimulates the anterior pituitary to produce TSH which in turn stimulates the thyroid to produce thyroid hormone until blood levels return to normal. This is a negative feedback look

Question 25

Describe the HPA axis (Hypothalmic-pituitary- adrenal axis) feedback loop

Answer 25

HPA axis is responsible for the stress response. Hypothalamus releases CRH (corticotropin-releasing factor) which binds to receptors on the anterior pituitary gland causing CTH to be released. ACTH binds to receptors on the adrenal cortex and stimulates the release of cortisol. At a certain blood level of cortisol , the cortisol exerts negative feedback on to the release of CRH and ACTH

Question 26

What are the 3 major neuroendocrine systems through whch the hypothalamus and anterior pituitary gland direct neuroendocrine function?

Answer 26

HPT axis HPA axis HPG axis

Question 27

Describe the HPG axis (Hypothalmic-pituitary-gonadal axis) feedback loop

Answer 27

Question 28

Describe the feedback loop in which vasopressin is released as a result of low blood pressure

Answer 28

Major restriction in blood volume is detected by baroreceptors

CN IX and CN X carry this information to the NTS in the brainstem

This either stimulates or inhibits the release of Vasporessin from the hypothalamus

Vasopressin acts of the V1 receptors on blood vessels, causing vasoconstriction and therefore an increase in blood pressure