hypothalamapituitary axis Flashcards
What connects the anterior pituitary to the hypothalamus?
Portal blood circulation
‘Release’ hormones from the hypothalamus enter this circulation to control anterior pituitary hormone release.
How do neurons of the hypothalamus interact with the posterior pituitary?
They project into the posterior pituitary and release hormones directly into systemic blood circulation.
What is the principal target of Antidiuretic Hormone (ADH)?
Kidney
ADH increases (re)-absorption in the kidney tubule.
What are the two main functions of oxytocin?
- Contractions of muscle in the uterus during childbirth
- Stimulates milk release from breast tissue
What are the four hormones produced by the anterior pituitary?
- Luteinizing hormone
- Follicle stimulating hormone
- Thyroid stimulating hormone
- Adrenocorticotrophic hormone
Which two hormones from the anterior pituitary have a direct effect on target tissues?
- Prolactin
- Growth hormone
What does Growth Hormone (GH) promote in all ages?
- Release of free fatty acids from adipose tissue
- Hepatic glycogen breakdown
- Increased blood glucose levels
What is the role of insulin-like growth factors (IGFs) in relation to Growth Hormone?
Enhances protein synthesis and promotes growth, particularly in childhood and adolescence.
What is the main function of prolactin?
Promote growth and development of breast tissue and stimulate breast milk production.
Where is Melanocyte-Stimulating Hormone produced?
Intermediate lobe of pituitary
It can be considered part of the anterior pituitary.
What does the pineal gland regulate?
Circadian rhythms by secreting melatonin.
What is the effect of melatonin on the body?
Described as ‘anti-aging’ e.g. reduces bone loss and age-related changes in organs.
What controls the secretion of melatonin?
A rhythm-generation centre in the suprachiasmatic nucleus (SCN) of the hypothalamus.
Is the endocrine pancreas controlled by the hypothalamopituitary axis?
No.
What is the effect of Growth Hormone on muscle?
Promotes uptake of amino acids across tissues to promote growth.
What hormone is necessary for the secretion of Growth Hormone?
Tri-iodothyronine (T3).
What is the unclear function of prolactin in males?
May be involved in regulation of androgen secretion.
What does ADH also cause aside from preserving water?
Vasopressive action – causes blood vessels to contract to increase blood pressure.
