Anatomy of the hypothalamus and pituitary gland Flashcards
Describe the positioning of the third ventricle?
Narrow vertical slit in the forebrain that runs antero-posteriorly along the midline above the midbrain
Lies between left and right thalamus
What does the hypothalamus consist of?
Group of nuclei on the side of the anterior most part of the third ventricle
Where does the pituitary gland lie?
Sits in pituitary fossa in the sphenoid bone below hypothalamus
How is the pituitary gland connected to the hypothalamus?
Via the pituitary stalk
What is known as the control centre of the autonomic nervous system?
Hypothalumus
What is the proper name for pituitary stalk?
Infundibulum
Which part of the pituitary gland is classified as part of the brain?
Posterior pituitary
2 outputs from hypothalamus to pituitary?
Mangocellular and parvocellular
Where do mangocellular neurones project to?
Posterior lobe
Where does the anterior lobe of the pituitary develop from?
Ectoderm in roof of the mouth.
Where does the posterior lobe of the pituitary develop from?
Downward pouch of brain tissue into floor of third ventricle
What surrounds the pituitary gland laterally
Cavernous sinus
What sensors does hypothalamus use to control body temperature?
Thermoreceptors on anterior nucleus of hypothalmus (blood temp) Cutaneous thermoreceptors (C fibre endings) for skin temp
3 changes that occur if temp is too high?
sweat secreted- heat lost by evaporation
cutaneous vasodilation: blood goes to superficial capillaries
person becomes inactive
4 changes that occur if temp is too low?
No sweat produced
Piloerection
Arteriole constriction
Shivering
What are some long term adaptations to high temperature?
Increasing number and activity of sweat glands and cutaneous capillaries
What are some long term adaptations to low temperature?
Increased secretion of thyroid stimulating hormone and deposition of body fat
Which nuclei in hypothalamus send axons to posterior pituitary to regulate water balance?
Paraventricular and supraoptic
Is posterior pituitary a fast or slow release system?
Fast release
What is the function of oxytocin?
Promotes milk release from milk ducts in lactating mother
2 main hormones secreted from posterior pituitary
ADH and oxytocin
What is the general sequence leading to hormone release from anterior pituitary gland?
Nuclei in hypothalamus release peptide hormones into capillaries
Act on endocrine cells in ant.
Pituitary cellss release ssecond hormone into venous blood
Name the 6 hormones released from anterior pituitary gland
Adrenocortiotrophic hormone Prolactin Luteinising hormone Follicle stimulating hormone Thyroid stimulating hormone Growth hormone
What hormone controls release of ACTH?
Released by corticotrophic releasing hormone
What hormone controls prolactin release?
Prolactin inhibiting factors inhibit release
What hormone controls release of LH?
Gonadotrophic releasing hormones
What hormone controls release of FSH?
Gonadotrophic releasing hormone
What hormone controls release of thyroid stimulating hormone?
Thryoid releasing hormone
Why is prolactin controlled by inhibitory control?
It is more active
What hormone(s) control release of growth hormone
Released by growth hormone releasing hormone
Inhibited by growth hormone inhibiting hormone
Where is cortisol released from?
Cells in adrenal cortex
Which part of the pituitary gland contains cortisol receptors
Anterior part
High levels of cortisol causes…
release of ACTH
What causes release of cortisol from adrenal cortex
High levels of ACTH
Why are anterior hormones released in a rhythmic fashion?
Because they are subject to compelx negative feedback regulation
