Endocrine System Quiz

1/14/26

Hormones

produced by specialized cells, secreted into extracellular fluids. transferred to target sites, and regulate activity of other cells

Amino acid based hormones

water soluble that include proteins, peptides, and amines

Steroids

made from cholesterol

Prostaglandins

made from highly active lipids, hormone-like effects, derived from fatty acids via enzyme activity

Direct gene activation (Steroid hormone action)

pass directly through the membrane and binds to a specific protein within the nucleus to activate genes

Second-Messenger System (Non-Steroid Hormone Action)

amino acids that can't get across the cell membrane, series of reactions is set off that activates an enzyme

G protein

molecular switches transmit signals

Enzyme

in plasma membrane

cAMP

2nd messenger derivative from ATP that turns off/on protein kinase

Negative feedback

corrective, around set level or equilibrium

Humoral stimuli

changing blood levels of certain ions stimulate hormone release, ex: parathyroid hormones, calcitonin, insulin

Neural stimuli

nerve impulses stimulate hormone release usually under control of the sympathetic nervous system, ex: release by adrenal medulla

Pituitary gland

pea-sized, hangs by a stalk from the hypothalamus, protected by sphenoid bone with the hypophyseal fossa, master endocrine gland

Sphenoid bone

"butterfly shaped" back of eye socket

Fossa

bony cavity (open space) which protects pituitary

Anterior pituitary

functional lobe of pituitary gland that is glandular tissue

Posterior pituitary

functional lobe of pituitary gland that is nervous tissue

Growth hormone (GH)

general metabolic hormone for growth of skeletal muscles and long bones, determines body seize, causes amino acids to be built to proteins and causes fats to be broken down for energy

Pituitary dwarfism

hyposecretion (little) of growth hormone during childhood

Gigantism

hypersecretion (a lot) of growth hormone during childhood

Acromegaly gigantism

hypersecretion of growth hormone during adulthood, not common anymore

Prolactin (PRL)

stimulates and maintains milk production following childbirth, male function is unknown

Adrenocorticotropic hormone (ACTH)

regulates endocrine activity of the adrenal cortex

Thyroid-stimulating hormone (TSH)

nfluences growth and activity of the thyroid gland

Gonadotrophic hormones

regulate hormonal activity of the gonads

Follicle-stimulating hormone (FS)

stimulates follicle development in ovaries, stimulates sperm development in testes

Luteinizing hormone (LH)

triggers ovulation of an egg in females in the anterior pituitary gland

Oxytocin (OT)

stimulates contractions of the uterus during labor and breastfeeding, causes milk ejection in a nursing woman, positive feedback, in posterior pituitary

Antidiuretic Hormone (ADH)

inhibits urine production by promoting water reabsorption by the kidneys

Vasoconstriction

caused by large amount of antidiuretic hormone which increases blood pressure and blood vessels decrease in diameter

Thyroid gland

found at the base of the throat and consists of 2 lobes and a connecting isthmus and produces the thyroid hormone and calcitocin

Thyroid hormone

major metabolic hormone that is composed of 2 active iodine-containing hormones, T4 and T3

Thyroxine (T4)

secreted by thyroid follicles

Triiodothyronine (T3)

conversion of T4 at target tissues, more "potent" thyroid hormone, converted by enzymes and gets an iodine atom removed, regulation of metabolism, energy, and cell function

Goiters

thyroid gland enlarges due to lack of iodine and salt is iodized to prevent this

Cretinism

severe lack of iodine during pregnancy caused by hyposecretion of thyroxine (T4) and results in dwarfism

Myxema

caused by hypothyroidism in adults and results in physical and mental sluggishness

Grave's disease

caused by hyperthyroidism, results in increased metabolism, heat intolerance, weight loss, and exophthalmos, eyes bulge

Calcitonin (CT)

decreases blood calcium levels by causing its deposition on bone (osteoblast activity), antagonistic to parathyroid hormone, produced by parafollicular cells

Parafollicular cells

produces calcitonin and are found between the follicles

Parathyroid glands

tiny masses on the posterior of the thyroid and secretes parathyroid hormone

Parathyroid hormone (PTH)

stimulate osteoclasts to remove calcium from the bone and stimulate the kidneys and intestine to absorb more calcium

Adrenal glands

on top of the kidneys and have two regions and are surrounded by fibrous capsule

Adrenal cortex

outer glandular region of adrenal gland with 3 layers: mineralocorticoids secreting area, glucocorticoids secreting area, and sex hormones secreting area

Adrenal medulla

inner neural tissue region of adrenal glands that produces epinephrine and norepinephrine

Mineralocorticoids

produced in outer adrenal cortex which regulates mineral content in blood, water and electrolyte balance which promotes Na reabsorption in the kidneys

Mineralocorticoid receptor (MR)

aldosterone binds to this, triggering gene expression for Na channels

Glucocorticoids

middle layer of adrenal cortex that helps do normal cell metabolism, resist long-term stressors, and is released in response to high blood levels of ACFH

Sex hormones

inner layer of adrenal cortex and are small amounts throughout life, mostly androgens and estrogens formed

Addison's disease

hyposecretion (little) of adrenal cortex hormones which causes bronze skin tone, weakened muscles, and susceptibility to infection

Hyperaldosteronism

may result from an ACTH-releasing tumor and excess water and sodium retained leading to high blood pressure and edema

Edema

fluid filled swelling trapped in body tissues often legs, ankles, feet, and hands

Cushing's syndrome

tumor in middle cortical area of adrenal cortex, moon face or buffalo bump appearance, high blood pressure, hyperglycemia, weakening of bones, depression

Masculinization

results from hypersecretion of sex hormones, and beard and male distribution of hair growth

Insulin

allows glucose to cross plasma membrane into cells from beta cells

Glucagon

allows glucose to enter the blood from alpha cells

Diabetes insipidus

condition where the body fails to properly control water balance, resulting in excessive urination caused by low/absent secretion of ADH and poor kidney response to ADH

Pineal gland

found on third ventricle of brain and secretes melatonin which helps with wake/sleep cycles

Thymus gland

located posterior to sternum and largest in infants and children and produces thymosin

Thymosin

matures some types of white blood cells and important in developing the immune system

Ovaries

produce eggs and produce two groups of steroid hormone: estrogen and progesterone

Testes

produce sperm and produce androgens like testosterone

Estrogen

stimulate the development of secondary female characteristics and mature female reproductive organs

Progesterone

acts with estrogen to bring about the menstrual cycle, helps in implantation of an embryo in the uterus, and helps prepare breasts for lactation

Testosterone

responsible for adult male secondary sex characteristics, promotes growth and maturation of male reproductive system and required for sperm cell production

Hypertrichosis

oversecretion of testosterone, excessive hair growth, thick terminal hairs