Showing posts with label Sex. Show all posts
Showing posts with label Sex. Show all posts

Thursday, June 11, 2015

Functions of the Hypothalamus

The Specific functions of the regions in the Hypothalamus

The Hypothalamus is located under the thalamus (thus the name), and is probably one of the most important region in the brain that helps maintain homeostasis in the body. It can be divided into 3 different regions:

Lateral Hypothalamus --- the hunger centre, it has special receptors thought to detect when the body needs more food or fluids. Stimulation in this region and trigger eating and drinking response. Lab mice with lesion in this region will starve to death if not force fed, because they cannot sense hunger.
Ventromedial Hypothalamus --- the "satiety centre". It is the region that senses fullness and stops you from eating. Lab mice with lesion in this region will become very obese, because they don't know when to stop eating.
Anterior Hypothalamus --- the sex centre. When this region is stimulated in the lab animals they will have sex with just anything they encounter
Last but not least, the Hypothalamus can also be stimulated in a danger or stress situation and initiate a "fight-or-flight" response by releasing corticotropin releasing hormone (CRF) to the anterior pituitary gland, which will release Adrenalcorticotropic hormone (ACTH) to the adrenal medulla to release epinephrine and norepinephrine to further stimulate the sympathetic nervous system)

Mnemonics:

Function 4Fs
  • Feed
  • Fight
  • Flight
  • Fuck
Region specific functions:
  • Destruction of the Lateral Hypothalamus (LH), one will Lack Hunger
  • Destruction of the VentroMedial Hypothalamus (VMH), one will be Very Much Hungry
  • Destruction of the Anterior Hypothalamus, one will be Asexual 

Functions of the Three Corticosteroids

What are the functions of the 3 corticosteroids?

The Adrenal Cortex produces three different kinds of corticosteroids:

Mineralocorticoids --- responsible for salt and water homeostasis. Aldosterone is a mineralocorticoid that can increase sodium reabsorption in the nephron, and can lead to increase in blood pressure. Aldosterone can also increase Potassium excretion through kidney.

Glucocorticoids --- regulates glucose levels, they also affect protein metabolism. The glucocorticoid most likely to appear on the MCAT is Cortisol which can raise blood glucose level by increasing gluconeogenesis and decreasing protein synthesis.

Cortical sex hormones ---Just as it sounds, cortical sex hormones (androgen and estrogen) affects the maturation of sex organs. A female fetus born with ambiguous or masculinized genital can be due to the presence of excess androgen.

Mnemonics:

3S's

  • Salt (mineralocorticoids)
  • Sugar (glucocorticoids)
  • Sex (cortical sex hormones)

Pathway of sperm in male reproductive system

SEVE(N) UP


  • Seminiferous tubules
  • Epididymis
  • Vas deferens
  • Ejaculatory duct
  • (Nothing)
  • Urethra
  • Penis