Lecture 18 - Hypothalamus and Pituitary

The hypothalamus links the __________ system to the __________ system.

nervous; endocrine

The hypothalamus is located __________ the thalamus and is part of the __________ system.

below; limbic

The hypothalamus communicates with the pituitary gland through the __________.

pituitary stalk (infundibulum)

The hypothalamus contains groups of neurons called __________ that regulate endocrine functions.

nuclei

The hypothalamic nuclei responsible for endocrine hormone production include the __________ nucleus, __________ nucleus, __________ nucleus, and __________ nucleus.

paraventricular; supraoptic; suprachiasmatic; arcuate

The __________ nucleus functions as the biological clock regulating circadian rhythms.

suprachiasmatic

The __________ nucleus contains the satiety center regulating appetite.

ventromedial

Damage to the ventromedial nucleus causes __________ and excessive __________.

hyperphagia; weight gain

The posterior pituitary is also called the __________.

neurohypophysis

The posterior pituitary releases two major hormones: __________ and __________.

ADH; oxytocin

ADH and oxytocin are produced in the __________ and __________ nuclei.

supraoptic; paraventricular

ADH and oxytocin travel down neuronal __________ to reach the posterior pituitary.

axons

These hormones are released into the __________ circulation.

systemic

Neurons that release hormones are called __________ cells.

neurosecretory

The anterior pituitary is also called the __________.

adenohypophysis

Hypothalamic releasing hormones travel to the anterior pituitary via the __________.

hypothalamo-hypophyseal portal system

Hypothalamic releasing hormones stimulate endocrine cells in the __________ pituitary.

anterior

The hypothalamic hormone that stimulates ACTH release is __________.

CRH

The hypothalamic hormone that stimulates TSH release is __________.

TRH

The hypothalamic hormone that stimulates growth hormone release is __________.

GHRH

The hormone that inhibits growth hormone secretion is __________.

somatostatin (GHIH)

The hypothalamic hormone that stimulates gonadotropins is __________.

GnRH

The hypothalamic hormone that inhibits prolactin is __________.

dopamine (PIH)

The pituitary gland is also called the __________.

hypophysis

The anterior pituitary originates from __________ ectoderm.

oral

The posterior pituitary originates from __________ ectoderm.

neural

The anterior pituitary is divided into __________, __________, and __________.

pars distalis; pars tuberalis; pars intermedia

The pars intermedia is particularly important in __________.

horses

Anterior pituitary hormone-producing cells are called __________.

chromophils

Chromophils are divided into __________ and __________.

acidophils; basophils

Acidophils include __________ cells that produce growth hormone.

somatotropes

Acidophils include __________ cells that produce prolactin.

lactotropes

Basophils include __________ cells that produce ACTH.

corticotropes

Basophils include __________ cells that produce TSH.

thyrotropes

Basophils include __________ cells that produce FSH and LH.

gonadotropes

Cells with little staining in the anterior pituitary are called __________.

chromophobes

The most common endocrine regulatory mechanism is __________ feedback.

negative

Negative feedback occurs when hormones __________ further hormone secretion.

inhibit

Positive feedback occurs when hormones __________ further hormone secretion.

stimulate

Positive feedback is __________ in endocrine systems.

rare

A classic example of positive feedback is the __________ surge before ovulation.

LH

Feedforward regulation refers to the __________ effect of one system regulating another.

anticipatory

In hypothalamus-pituitary dependent systems, hormone secretion stops if the __________ or __________ is removed.

hypothalamus; pituitary

The adrenal axis begins with hypothalamic secretion of __________.

CRH

CRH stimulates pituitary release of __________.

ACTH

ACTH stimulates the adrenal cortex to release __________.

cortisol

Cortisol exerts __________ feedback on the hypothalamus and pituitary.

negative

The hypothalamus secretes __________ to stimulate the thyroid axis.

TRH

TRH stimulates pituitary release of __________.

TSH

TSH stimulates the thyroid gland to produce __________ and __________.

T3; T4

T3 and T4 regulate __________ and __________.

metabolism; growth

GnRH stimulates release of __________ and __________ from the pituitary.

LH; FSH

In females, LH and FSH stimulate the ovaries to produce __________.

estrogen

Granulosa cells produce __________ which inhibits FSH.

inhibin

In males, LH stimulates __________ production.

testosterone

Sertoli cells produce __________ which inhibits FSH.

inhibin

Growth hormone is released from the __________ pituitary.

anterior

Growth hormone stimulates the liver to produce __________.

somatomedins (IGF-1)

IGF-1 stimulates tissue and __________ growth.

bone

IGF-1 stimulates hypothalamic release of __________ which inhibits GH.

somatostatin

Prolactin secretion is stimulated by __________.

PRH

Prolactin secretion is inhibited by __________.

dopamine

Prolactin acts primarily on the __________ glands.

mammary

Oxytocin release is stimulated by __________ during lactation.

nursing

Cervical stimulation during __________ also triggers oxytocin release.

parturition

The oxytocin reflex is an example of a __________ loop.

positive

ADH stands for __________ hormone.

antidiuretic

ADH acts on the __________ to conserve water.

kidneys

ADH release increases when plasma __________ increases.

osmolarity

ADH release decreases when plasma osmolarity __________.

decreases

The pancreas regulates blood __________ levels.

glucose

The pancreas secretes __________ and __________.

insulin; glucagon

The parathyroid glands regulate blood __________ levels.

calcium

The adrenal medulla is controlled by the __________ nervous system.

sympathetic