Lecture 1: Hypothalamus/Pituitary

Question 1

ANTERIOR and POSTERIOR PITUITARY components?

Answer 1

Anterior: Andenohypophysis

• Pars tuberalis
• Pars intermedia
• Pars distalis

Posterior: Neurohypophysis

• Median eminence
• Pars nervosa

Question 2

Most secreting cells in the thalamus form?

Answer 2

Nuclei

Question 3

Blood supply of the Pituitary gland?

Answer 3

Question 4

Posterior lobe nerve involvement?

Answer 4

Some nerves such as those from the Supraoptic and Paraventricular nuclei produce ADH and Oxcytocin, respectively, these are released by the synaptic terminals at the capillaries in the posterior lobe of the gland itself.

Question 5

Hypophyseal Portal System?

Answer 5

Is a capillary networks in the median eminance are supplied by the superior hypophyseal artery. Before leaving the hypothalamus the capillary networks unite to form a series of large vessels that spiral around the infundibulum to reach the anterior lobe.

It is the vessels that carry blood between these two capillary beds that form the hypophyseal portal system.

Question 6

Mechanism of Growth Hormone relaease and feedback?

Answer 6

GH-IH = Growth hormone-Inhibiting hormone

GH-RH = Growth hormone-Releasing hormone

Question 7

Oxytocin and Prolactin release? Prolactin feedback?

Answer 7

Prolactin Feedback:

• Regulates its own synthesis and release.
• Dopamine is secreted in the median eminence
• Prolactine is released from APG and acts negatively on the tuberoinfundibular dopamine (TIDA) neurons in hypothal.

During Pregnancy we see massive changes with placental lactogens that bypass the feedback as well as a switch from negative to positive feedback.

Suckling stimulus from child also plays a massive role in release.

Question 8

Hormonal control of Male HPG axis?

Answer 8

Question 9

The menstrual cycle hormone levels?

Answer 9

• Estrogen is partly the cause for the switch in feedback of LH causing a large spike of FSH and LH and thus ovulation.
• Progesterone is produced by the corpus luteum and maintained high in pergnancy

Question 10

Binding of FSH and LH?

Answer 10

LH binds to thecal cells where as FSH binds onto the granulosa cells

Question 11

Female estrogen feedback on HPG axis?

Answer 11

• Progesterone inhibits both APG and GnRH neuron
• estrogen produced by dominant follicles acts positively

Question 12

If Heape Daddy kisses a 10 year old boy will he start puberty?

Answer 12

Puberty starts due to Kisspeptine neurons firing not from a kiss silly.