Neuroscience exam 3

What is the neuroendocrine function?

Interaction between neurons, glands, hormones, and receptors in organs including the brain.

What are glands?

Organs whose primary function is to release hormones.

How are hormones similar to neurotransmitters?

They reach target organs and bind receptors to trigger cellular events; some hormones are released by neurons via vesicles.

How are hormones different from neurotransmitters?

They travel long distances via bloodstream, act slowly, and remain longer in circulation.

What is the pituitary gland known as?

The “master gland” because it releases hormones that control other glands.

What are the two parts of the pituitary?

Anterior pituitary and posterior pituitary.

What connects the hypothalamus and posterior pituitary?

Neurons from the paraventricular (PVN) and supraoptic nuclei.

What hormones are released from the posterior pituitary?

Oxytocin and vasopressin.

How do posterior pituitary hormones reach the blood?

Direct release from axon terminals into capillaries.

Oxytocin — key functions?

Uterine contractions, milk ejection, orgasm, maternal behavior, pair bonding, trust

How does the anterior pituitary release hormones?

Hypothalamic releasing factors travel through a portal system to stimulate hormone release.

What does the anterior pituitary regulate?

Sexual development, growth, and stress.

What is the hormonal stress pathway?

Hypothalamus → CRH → Anterior Pituitary → ACTH → Adrenal cortex → Cortisol.

What is the neural stress pathway?

Hypothalamus → Sympathetic nervous system → Adrenal medulla → Epinephrine & norepinephrine.

Adrenal cortex vs medulla — what do they release?

Cortex: cortisol, androgens, estrogens. Medulla: epinephrine, norepinephrine.

Immediate stress response?

Epinephrine/norepinephrine.

Delayed stress response?

Cortisol.

What happens under chronic stress?

High cortisol, immune suppression, reduced reproductive function.

What did visible burrow system studies show?

Subordinate rats: high cortisol, low testosterone. Dominant rats: low cortisol, normal testosterone.

What hormone does the hypothalamus release for sexual behavior?

Gonadotropin-releasing hormone (GRH).

What hormones does the anterior pituitary release in response to GRH?

Gonadotropins (LH and FSH).

What do gonadotropins do?

Stimulate gonads (ovaries/ testes) to release androgens and estrogens.

What determines male vs female gonad development?

SRY protein on the Y chromosome → testes development

What happens without SRY?

Ovaries develop → default female pathway.

What do testes release during development?

Testosterone + Mullerian-inhibiting substance (MIS).

What does MIS do?

Causes Mullerian ducts to regress (blocks female duct development)

What hormone masculinizes the brain?

Estradiol.

Why don’t female brains masculinize?

Alpha-fetoprotein binds estradiol in blood and prevents it from entering the brain.

How do males get estradiol in the brain if AFP blocks it?

Testosterone enters brain → aromatase converts it into estradiol.

What brain region controls male sexual behavior?

Medial preoptic area (mPOA). Lesion = no copulation.

What triggers female sexual receptivity?

Estradiol (48 hours before) + progesterone (4 hours before).

What is lordosis?

Female receptive posture (elevated rump, tail to side).

What nucleus of the hypothalamus regulates feeding?

Arcuate nucleus.

What do AGRP/NPY neurons do?

Stimulate feeding (hunger).

What do POMC neurons do?

Suppress feeding (satiety).

What hormone activates hunger neurons?

Ghrelin (from stomach).

What hormone activates satiety neurons?

Leptin (from fat cells).

What is the difference between ob/ob and db/db mice?

ob/ob = no leptin. db/db = no receptors

What tools measure sleep stages?

EEG, EMG, EOG.

What are the 2 major sleep types?

Slow wave sleep (SWS) and REM sleep.

What characterizes REM sleep?

Awake-like EEG, muscle paralysis, rapid eye movements, vivid dreams.

What causes narcolepsy?

Loss of hypocretin-producing neurons.

Where is hypocretin made?

Lateral hypothalamus.

What characterizes SWS?

Delta waves, sleep spindles, K-complexes, high-amplitude slow waves.

What happens when hypocretin neurons are activated?

Transition from sleep → wakefulness.

What is cataplexy?

A sudden loss of msucle tone, often triggered by emotion.