Zoology Exam 3 - Chemical Coordination: Endocrine system (Hormones)

Hormones

Secreted by tissues into blood, carried to and interpreted by cells elsewhere in the body

Endocrine System

System of glands that secrete hormones

Pituitary Gland (Hypophysis)

Regulates other glands, very small

Anterior (Adenohypophysis)

A portion of the pituitary gland, glandular, produces TSH, FSH, LH, GH, and prolactin

TSH

Thyroid-stimulating hormone

Follicle-stimulating hormone (FSH)

From the anterior lobe of the pituitary

Luteinizing hormone (LH)

Produced in anterior pituitary, luteinizes mature follicle so it becomes the corpus luteum, peaks at ovulation

GH

Growth Hormone

Prolactin

Milk production

Posterior (Neurohypophysis)

A portion of the pituitary gland, neural tissue, releases hormones in response to action potentials

Oxytocin

Uterine contraction and milk release

Vasopressin (ADH)

Antidiuretic hormone, resorption of water by kidney

Thyroxine

Causes metamorphosis in amphibians; requires iodine to be made

Adrenal Cortex

Produces various steroids

Adrenal Medulla

Epinephrine (adrenaline) - fight or flight

Pancreas

Insulin and glucagon - regulate blood glucose

Testes

Androgens - maleness

Ovaries

Estrogens - femaleness, progesterone for uterus/breasts function

Estrogen

From mature follicle - starts developing uterus for implantation (gets the lining, or endometrium, ready)

Progesterone

Produced by corpus luteum, promotes, pregnancy, maintains endometrium, inversely related to estrogen

Menstrual Cycle

In humans and gorillas, endometrium (uterine lining) sheds off, female is sexually receptive even when an egg may not be ready for fertilization

Estrous Cycle

In other mammals, also called “heat”, female becomes sexually receptive only when an egg is ready for fertilization

Polyestrous

Animals with several cycles, breed many times yearly (rodents)

Monestrous

Animals breed once per year