ANAPHY ENDOCRINE PART 1

Direct gene activation

Used by steroid hormones and thyroid hormone

Amino acid-based

• Proteins

• Peptides

• Amines

Steroids

• made from cholesterol; fat soluble

• regulating metabolism, inflammation, immune function, salt-water balance, development, and reproduction.

Prostaglandins

made from highly active lipids (arachidonic acid) that act as local hormones

Second-messenger system

Used by protein and peptide hormones

Hormone levels in the blood are maintained mostly by?

negative feedback mechanisms

Hormonal Stimuli

• Most common category of stimulus

• Endocrine organs are activated by other hormones

Example:

• Hormones of the hypothalamus stimulate the anterior pituitary to secrete its hormones

Hypothalamus

center; release thyrotropin-releasing hormone (TRH)

Pituitary gland

master gland; receives order from hypothalamus to release thyrotropin or thyroidstimulating hormone (TSH)

Humoral Stimuli

• Changing blood levels of certain ions and nutrients stimulate hormone release

• indicates various body fluids, such as blood and bile

Examples:

• Parathyroid hormone (low levels) and calcitonin (high levels) are produced in response to changing levels of blood calcium levels

Neural Stimuli

• Nerve fibers stimulate hormone release

• - Most are under the control of the sympathetic nervous system

Examples:

• Sympathetic stimulation of the adrenal medulla to release epinephrine and norepinephrine

Anterior pituitary

• glandular tissue

• Often called the "master endocrine gland" because it controls activities of so many other endocrine glands

Posterior pituitary

nervous tissue; only produces antidiuretic hormone (ADH) and oxytocin

Oxytocin

• Only released in significant amounts during childbirth and nursing

• Stimulates contractions of the uterus during labor, sexual relations, and breastfeeding

• Causes milk ejection (let-down reflex) in a nursing woman

Antidiuretic hormone (ADH)

• inhibits urine production (diuresis) by promoting water reabsorption by the kidneys

• Urine volume decreases, blood volume and pressure increase

• In large amounts, ADH causes constriction of arterioles, leading to increased blood pressure (the reason why ADH is known as vasopressin)

• Alcohol inhibits ADH secretion

tropic hormones

stimulate other endocrine glands to release hormones

Growth hormone (GH)

• General metabolic hormone

• Major effects are directed to growth of skeletal muscles and long bones

• Plays a role in determining final body size

Prolactin (PRL)

Stimulates and maintains milk production following childbirth

Gonadotropic hormones

Regulate hormonal activity of the gonads

Follicle-stimulating hormone (FSH)

• Stimulates follicle development in ovaries

• Stimulates sperm development in testes

Luteinizing hormone (LH)

• Triggers ovulation of an egg in females

• Stimulates testosterone production in males