Chapter 19: Endocrine Glands

What is the role of the pituitary gland?

Regulates other endocrine glands.

What is the role of the hypothalamus?

Regulates secretion of the anterior pituitary gland.

What connects the posterior pituitary to the hypothalamus?

Infundibulum (pituitary stalk)

What hormones are produced in the hypothalamus but stored in the posterior pituitary?

ADH (vasopressin) and Oxytocin

How does the hypothalamus control the anterior pituitary?

Via the hypothalamohypophysial portal system using releasing and inhibiting hormones.

What is the effect of GHRH?

Stimulates growth hormone secretion from anterior pituitary.

What is the effect of GHIH (Somatostatin)?

Inhibits growth hormone secretion.

What does TRH do?

Stimulates TSH secretion.

What does CRH do?

Stimulates ACTH secretion.

What does GnRH do?

Stimulates LH and FSH secretion.

What does PIH (Dopamine) do?

Inhibits prolactin secretion.

What stimulates ADH release?

↑ blood osmolality (osmoreceptors), ↓ blood volume (baroreceptors).

What is ADH's target and response?

Kidney → ↑ water reabsorption → ↓ urine, ↑ blood volume.

What happens in diabetes insipidus?

Hyposecretion or insensitivity to ADH → cannot concentrate urine → large volumes of dilute urine.

What stimulates Oxytocin release?

Cervical pressure, uterine stretch, nipple stimulation.

What is Oxytocin's target and response?

Uterus → contractions; mammary glands → milk release.

What is the acronym for anterior pituitary hormones?

My Little Blue FLAT PiG → GH, LH, FSH, ACTH, TSH, Prolactin, MSH, β-Endorphins, Lipotropins.

What stimulates GH release?

GHRH, low blood glucose, stress, circadian rhythms.

What is GH's target and response?

Most tissues → ↑ protein synthesis, growth, fat breakdown, glucose synthesis, IGF secretion.

What are the disorders of GH?

Hyposecretion → Pituitary dwarfism; Hypersecretion before epiphyseal closure → Gigantism; after closure → Acromegaly.

What is Prolactin's target and response?

Ovaries & mammary glands → milk production, progesterone secretion.

What is TSH's target and response?

Thyroid gland → release of T3 & T4.

What is ACTH's target and response?

Adrenal cortex → cortisol secretion; binds melanocytes → ↑ melanin.

What is the effect of MSH?

Stimulates melanocytes to produce melanin.

What is the effect of β-Endorphins?

Analgesia during stress.

What is the effect of Lipotropins?

Fat catabolism in adipose tissue.

What is LH's target and response?

Ovaries/Testes → regulates gamete & hormone production.

What is FSH's target and response?

Ovaries/Testes → regulates gamete & hormone production.

Where is the thyroid gland located?

Inferior to the larynx.

What do follicular cells produce compared to parafollicular cells?

Follicular → T3 & T4; Parafollicular → calcitonin.

What is the function of T3 & T4?

↑ metabolism, increase body temp, support growth & maturation.

How are thyroid hormones regulated?

TRH → TSH → T3/T4; negative feedback inhibits TRH & TSH.

What is the function of calcitonin?

↓ blood Ca²⁺ → inhibits osteoclasts, ↑ osteoblast lifespan, bone deposition.

What stimulates PTH release?

↓ blood Ca²⁺.

What is the effect of PTH?

↑ Ca²⁺ by stimulating osteoclasts, ↑ kidney reabsorption, ↑ vitamin D → intestine Ca²⁺ absorption.

What are the cortex zones and hormones of the adrenal glands?

Glomerulosa → aldosterone (salt), Fasciculata → cortisol (sugar), Reticularis → androgens (sex).

What hormones are produced by the adrenal medulla and their effect?

Epinephrine (80%), Norepinephrine (20%) → ↑ glycogen breakdown, heart rate, vasodilation in muscles, ↓ digestion.

What is the effect of aldosterone?

↑ Na⁺ & water reabsorption → ↑ BP; ↑ K⁺ & H⁺ excretion.

What is the effect of cortisol?

↑ protein/fat breakdown, ↑ gluconeogenesis, ↓ inflammation.

What is the effect of androgens?

Pubic & axillary hair growth, sex drive in females.

What is the exocrine vs endocrine function of the pancreas?

Exocrine → digestive juices; Endocrine → pancreatic islets (α: glucagon, β: insulin, δ: somatostatin).

What is the target and effect of insulin?

Liver, muscle, adipose → ↑ glucose & amino acid uptake → energy storage.

What is the target and effect of glucagon?

Liver → glycogen/fat breakdown, gluconeogenesis.

What regulates insulin?

Stimulated by ↑ blood glucose, ↑ amino acids, parasympathetic stimulation, GI hormones.

What regulates glucagon?

Stimulated by ↓ blood glucose, certain amino acids, sympathetic stimulation.

What happens right after a meal?

↑ insulin, ↓ glucagon, cortisol, GH, epinephrine → glucose uptake & storage.

What happens a few hours after a meal?

↑ glucagon, cortisol, GH, epinephrine → glucose release & lipid metabolism.

What occurs during short-term exercise?

Sympathetic stimulation → ↑ epinephrine & glucagon, ↓ insulin → glycogen → glucose, ↑ fat metabolism.

What occurs during long-term exercise?

Cortisol & GH → ↑ protein & lipid breakdown, ↓ glucose metabolism.

What is the effect of testosterone and inhibin in males?

Testosterone → sex organ development; Inhibin → inhibits FSH.

What are the effects of estrogen, progesterone, inhibin, and relaxin in females?

Estrogen → sex organ development & menstrual cycle; Progesterone → menstrual cycle & pregnancy support; Inhibin → inhibits FSH; Relaxin → ↑ flexibility of connective tissue.

What is the effect of melatonin?

Hypothalamus → inhibits GnRH, ↑ tendency to sleep; inhibited by light.

What hormone does the thymus produce?

Thymosin → lymphocyte maturation.

What hormone does the heart produce?

ANP → kidneys & vessels → fluid volume & BP regulation.

What hormone does the kidney produce?

Erythropoietin → bone marrow → RBC production.