Animal Hormones Flashcards

Flashcards about Animal Hormones

Hormones

Chemical signals that enter the blood and activate target cells.

Paracrines

Affect target cells near the release site.

Autocrines

Bind to receptors on the same cells that secrete them.

Endocrines

Chemical signals secreted by epithelial cells directly into the extracellular fluid (ECF).

Neuroendocrines/Neurohormones

Are secreted by neurons and enter the circulation.

Pheromones

Are chemical signals released from the body of an animal to influence the (sexual) behavior and physiology of other animals.

Hormone

Chemical non-nutrient, intercellular messenger that is effective at micromolar concentrations or less (high efficiency).

Peptide and protein hormones

Water-soluble, easily transported in blood, can be packaged in vesicles and released by exocytosis.

Steroid hormones

Synthesized from cholesterol, lipid-soluble, pass easily through cell membranes, usually bound to carrier molecules in the blood.

Amine hormones

Mostly synthesized from the amino acid tyrosine, some are water-soluble; others are lipid-soluble; their modes of release differ accordingly.

Antidiuretic hormone (ADH)

Increases the water retained by the kidneys when necessary and causes the constriction of peripheral blood vessels to elevate blood pressure

Oxytocin

Stimulates uterine contractions in childbirth and milk flow.

Tropic hormones

Hormones that control other endocrine glands

Growth hormone (GH)

Stimulates cells to take up amino acids, and liver cells to produce signals to stimulate growth of bone and cartilage.

Melanocyte-stimulating hormone (MSH)

Stimulates production of melanin in skin and hair.

Endorphins and enkephalins

Neuro-transmitters in the brain; natural painkillers.

Negative feedback control

Hormones from the target glands they stimulate

Prothoracicotropic hormone (PTTH)

Cells in the brain produce this hormone, which is stored in the corpora cardiaca.

Ecdysone

Secreted by the prothoracic gland. It diffuses to target tissues and stimulates molting.

Juvenile hormone

Released continuously from the corpora allata, which prevents maturation to adult form.

Juvenile hormone

Larvae molt into larger instars as long as this hormone is present in large amounts.

Androgens

Male steroid hormones; dominant form is testosterone.

Estrogens and progesterone

Female steroid hormones; dominant form is estradiol, which is synthesized from testosterone.

Thyroxine

Regulates metabolism; produced by follicle epithelial cells.

Calcitonin

Is produced by cells between the follicles and is involved in blood calcium regulation.

Thyroglobulin

A polymer of tyrosine that is produced and secreted into the lumen of the follicle, where it is iodinated and stored until processed by the epithelial cells to generate T3 and T4.

Glucagon

Secreted by alpha () cells and is released between meals when blood glucose concentration is falling.

Insulin

Secreted by beta () cells during and after a meal when glucose and amino acid blood levels are rising

Somatostatin

Secreted by D or delta () cells and partially suppresses secretion of glucagon and insulin and inhibits nutrient digestion and absorption which prolongs absorption of nutrients.

Hyperglycemic hormones

Hormones that raise blood glucose concentration.

Hypoglycemic hormones

Hormones that lower blood glucose.

Adrenal medulla

Produces epinephrine (adrenaline) and norepinephrine.

Adrenal cortex

Produces steroid hormones and is under hormonal control by tropic hormones produced in the anterior pituitary.

Mineralocorticoids

Influence salt and water balance. Aldosterone stimulates kidneys to conserve Na and excrete K.

Glucocorticoids

Influence blood glucose concentration.

Cortisol

Mediate metabolic stress responses.

Pineal gland

Secretes the hormone melatonin in a daily rhythm and coordinates daily rhythms of physiological functions.