Hypothalamus and Pituitary Gland

True or False: The posterior pituitary gland synthesizes antidiuretic hormone and oxytocin.

False: STORES

What are the divisions of the hypothalamus?

following the third ventricle, there are the periventricular, medial, and lateral divisions

What is the function of the supraoptic nucleus?

antidiuretic hormone (aka vasopressin)

What is the function of the paraventricular nucleus?

antidiuretic hormone, oxytocin, water conservation

What is the function of the ventromedial nucleus?

satiety

What is the function of the lateral hypothalamic nucleus?

hunger, thirst, blood pressure, heart rate

What is the function of the suprachiasmatic nucleus?

circadian rhythms

What is known as the excitatory cardiovascular center? Therefore increasing arterial pressure and heart rate.

lateral hypothalamic nucleus

What is known as the inhibitory cardiovascular center? Therefore decreasing arterial pressure and heart rate.

posterior hypothalamic nucleus and preoptic nucleus

What regulates respiration?

chemoreceptors (CO2, O2, H+) in hypothalamus

What regulates urination and defecation?

spinal reflexes at higher centers such as cortex

What is known as the satiety center?

ventromedial nucleus

What is known as the hunger center?

lateral hypothalamic nucleus/area

What prevents temperature rise to regulate body temperature?

anterior hypothalamus

What prevents temperature loss to regulate body temperature?

posterior hypothalamus

Between the anterior and posterior pituitary glands, which one forms the pituitary stalk and is known to be an extension of the hypothalamus?

posterior

What are tropic hormones?

hormones that regulate the function of other hormones to regulate function of endocrine glands

The anterior pituitary is the only division of the pituitary gland to produce tropic hormones. What are they?

TSH, ACTH, FSH, LH (thyroid stimulating hormone, adrenocorticotropic hormone, follicle stimulating hormone, and leutinizing hormone)

What are the non-tropic hormones produced by the anterior pituitary?

GH, PRL, MSH (growth hormone, prolactin, and melanocyte stimulating hormone)

What are the only two hormones stored in the posterior pituitary? (non-tropic)

ADH (aka vasopressin) and OCT (oxytocin)

What are the components of the anterior pituitary gland (pars anterior) cells?

chromophil and chromophobe cells

What are chromophil cells and what can they be classified into?

cells will granules in the cytoplasm that are either acidophils or basophils

What are examples of acidophilic chromophil cells?

somatotrophs and mammotrophs

What are examples of basophilic chromophil cells?

corticotrophs, thyrotrophs, and gonadotrophs

What is a chromophobe cell?

cells that contain very few granules in cytoplasm

What is the effect of corticotropin releasing hormone (CRH) on the pituitary?

stimulates ACTH secretion

What is the effect of thyrotropin releasing hormone (TRH) on the pituitary?

stimulates TSH and prolactin secretion

What is a hypothalamic releasing hormone that is known for inhibiting GH secretion?

somatostatin

What is the prolactin inhibiting hormone from the hypothalamus?

dopamine

What is the non-tropic hormone produced by anterior pituitary gland that will dull the perception of pain?

β-endorphin

What are both MSH and β-endorphin are formed by cleavage of what?

same precursor protein that gives rise to ACTH

What is the difference between oxytocin and ADH?

3rd and 8th amino acids in 9aa chain

What is an indicator of oxytocin and ADH secretion?

neurophysins carrier proteins

What are the main functions of oxytocin in females?

stimulation of milk ejection (milk let down), uterine muscle contraction during parturition/birth, and establishment of maternal behavior

What are the main functions of oxytocin in males?

sperm transport and sexual behavior

What inhibits oxytocin release?

catecholamines from acute stress

Where are ADH and oxytocin synthesized in the hypothalamus?

paraventricular nucleus and supraoptic nucleus

What is the most important physiological effect of ADH?

conserve fluid in the body by reducing urine output

What occurs in absence of ADH?

kidney tubules are virtually impermeable to water so it flows out as urine

What is the overall effect of ADH on osmolarity?

water reabsorption into kidney tubules and back into blood causes a decrease in plasma osmolarity and increased osmolarity of urine

What is the vascular effect (pressor) of ADH? Minimal pressor effect on healthy animals.

high concentrations of ADH cause widespread constriction of arterioles, which lead to increased arterial pressure

What controls the secretion of ADH?

plasma osmolarity; concentration of solutes in blood

Although not nearly as sensitive a stimulator as osmolarity, what can also regulate ADH secretion?

blood pressure and volume

What are the two different types of diabetes insipidus?

hypothalamic (central) or nephrogenic

What is hypothalamic (central) diabetes insipidus?

deficiency in secretion of ADH from posterior pituitary from things like head trauma, infection or tumor

What is nephrogenic diabetes insipidus?

kidney is unable to respond to ADH most commonly due to renal disease and less likely by mutations

What are the main functions of the pineal gland?

secretes melatonin and inhibits gonadotropin secretion in children to regulate the onset of puberty and allow children to sleep more