Lecture 2

Cholesterol-based hormones

Hormones derived from cholesterol, including steroids like testosterone.

Endocrine system

A system that distributes hormones through the bloodstream to target organs.

Exocrine system

A system that secretes substances through ducts to the outside of the body or into the digestive tract.

Infundibulum

The stalk that connects the hypothalamus to the pituitary gland.

Hypothalamus

The brain region that usually produces releasing hormones.

Pituitary gland

An endocrine gland that usually produces stimulating hormones.

Anterior pituitary hormones

Six hormones, including FSH, LH, TSH, ACTH, PRL, and GH are produced by the

Posterior pituitary hormones

Two hormones, ADH and oxytocin, produced in the hypothalamus and stored in the

Oxytocin

A hormone that plays important roles in lactation, emotional bonding, and labor contractions.

Negative feedback

A mechanism where increased hormone levels inhibit further hormone release.

Positive feedback

A mechanism where stretching of the uterus increases oxytocin release, causing more contractions.

Growth hormone (GH)

A hormone that stimulates growth and cell reproduction, influenced by IGF-I.

Giantism

A condition caused by hypersecretion of growth hormone during childhood.

Pituitary dwarfism

A condition resulting from hyposecretion of growth hormone.

Pineal gland

A gland located beneath the corpus callosum that synthesizes melatonin.

Melatonin

A hormone synthesized by the pineal gland that regulates sleep-wake cycles.

Thymus

An organ involved in the endocrine and immune systems, maturing T cells.

Thyroid gland

The largest purely endocrine gland, secreting hormones like T3 and T4.

Calcitonin

A hormone that lowers blood calcium levels by storing it in the bones.

Parathyroid hormone (PTH)

A hormone that increases blood calcium levels and decreases urinary excretion.

Adrenal glands

Glands located on top of the kidneys that produce steroids, catecholamines, and hormones.

Zona glomerulosa

The outer layer of the adrenal cortex that secretes mineralocorticoids like aldosterone.

Zona fasciculata

The middle layer of the adrenal cortex that secretes glucocorticoids like cortisol.

Zona reticularis

The inner layer of the adrenal cortex that secretes sex hormones.

Adrenal medulla

The inner part of the adrenal gland that releases catecholamines into the bloodstream.

Catecholamines

Hormones like epinephrine and norepinephrine that prepare the body for physical activity.

SLUDDE

An acronym for the parasympathetic effects: salivation, lacrimation, urination, defecation, dyspnea, emesis.

GFR

An acronym for the adrenal cortex memory triggers: salt, sugar, and sex.

Feedback mechanisms

Processes that control hormone secretion through positive and negative feedback loops.

Hypoparathyroidism

A condition caused by surgical excision, leading to fatal tetany.

Hyperparathyroidism

A condition caused by a parathyroid tumor, leading to soft and fragile bones.