Lecture 2 - Pituitary Gland Flashcards
Where is the pituitary gland located?
Below the brain and within the skull
What connects the pituitary gland to the brain?
Infundibulum
What hormones does the posterior pituitary release?
ADH and Oxytocin
What nuclei in the hypothalamus produce the hormones of the posterior pituitary?
- Supraoptic nuclei
- Paraventricular nuclei
How does ADH causes more water to be reabsorbed?
1) Activation of V2 receptors causes the translocation of AQP2 to the membrane of the kidney tubule.
2) This then causes more water to be reabsorbed, so less gets excreted.
What happens to the posterior pituitary hormones when they are released from the hypothalamus?
1) Released as inactive precursors (get activated in the posterior pituitary)
2) Travel through the hypothalamic-neurohypophyseal tract to the posterior pituitary
What second messenger does oxytocin use?
IP3
What changes does oxytocin induce?
Contraction of the smooth muscle of the uterus and breasts
What stimulates the secretion of oxytocin?
Stimulation of the vagina and/or nipples
What is the role of oxytocin during labour?
Causes the smooth muscle of the cervix to contracting, aiding with the expulsion of the baby.
Continuous stimulation of the cervix leads to continuous secretion of oxytocin.
Although it isn’t required to initiate normal labour, it can be administered to induce labour.
How does oxytocin aid with lactation?
Allows for the let down of milk (expulsion).
The stimulus for this let down is suckling of the nipples, however, there is a short delay before the milk is released.
What is the anterior pituitary an upgrowth from?
Palate
What hormones does the anterior pituitary release?
- Growth Hormone
- Prolactin
- Thyroid Stimulating Hormone (TSH)
- Adrenocorticotrophic Hormone (ACTH)
- Follicle Stimulating Hormone
- Luteinising Hormone
Where are anterior pituitary hormones synthesised?
Anterior Pituitary
What cells synthesise TSH?
Thyrotrophe cells
