Module 12: The Endocrine System Flashcards
target cells
cells that respond to hormones
Functions of hormones
growth/repair balance of energy response to stress maintain pH Reproduction
Endocrine system vs nervous system
Endo: communicated with body cells through hormones
Effects are in minutes/hours/weeks
Nervous: communicates with body cells through electrical impulses and chemical neurotransmitters
Effects in seconds
Major endocrine glands
Pituitary Thyroid Parathyroid Adrenal Pineal Thymus
Other tissue that produces hormones
pancreas
gonads
hypothalamus
Chemical classification of hormones
Amino based - proteins, most hormones are this
Steroid - synthesized by cholesterol, sex hormones and those from adrenal cortex
Protein hormones react with receptors on the
surface of the cell
rapid reactions
steroid hormones react with receptors on the
inside of a cell
slow reactions
Negative feeback
info about effects of hormones is “fed back” to gland which decreases secretion of the hormone
Neural stimuli
Hormones affected by direct stimuli to cause a gland to secrete its hormone
Hormonal Stimuli
hormones that are controlled in response to other hormones
Pituitary gland
“master gland”
aka hypophysis
Anterior and posterior
Hypothalamus
controls pituitary gland
adenohyphophysis (regulates hormonal secretions into blood vessels; stop or start secretion)
neurohypophysis (produced in hypothalamus and sent into capillary bed to be stored and released)
Hormones associated with hypothalamus
Growth hormone thyroid stimulating hormone (TSH) Adrenocorticoprophic (ACTH) FSH LH Prolactin (PRL) Oxytocin Antidiuretic (ADH)
Growth hormone (GH)
aka somatotropin
targets most body tissue
stimulates growth by promoting protein synthesis
Thyroid stimulating hormone (TSH)
aka thyrotropin
targets thyroid gland
stimulates production of thyroid hormones
Adrenocorticotrophic Hormones (ACTH)
targets cortex of adrenal glands
stimulates production of hormones in adrenal cortex
Follicle stimulating hormones (FSH)
targets testes and ovaries
stimulates production of sperm, maturation of ova and production of estrogen by ovaries
Luteinizing hormones (LH)
targets reproductive organs
stimulates production of testosterones, estrogen and progesterone
stimulates ovulation
Prolactin (PRL)
targets mammary glands
stimulates milk production
Oxytocin
targets uterus, mammary glands
stimulates uterine contractions/labor
Simulates ejection of milk
Antidiuretic hormone (ADH)
aka vasopressin
targets kidneys
Increases water reabsorption in tubules
Thyroid gland
very vascular
2 lobes connected by isthmus
Internally has follicles (thyroid hormones) and parafollicular cells (produce calcitonin)
Thyroid gland hormones
T3 (triiodothyronine)
T4 (thyroxine or tetraiodothyronine)
Calcitonin
T3 and T4
targets most body cells
regulates energy balances
increases rate of protein synthesis
regulates growth
Calcitonin
targets bone tissue
regulates calcium blood levels by inhibiting the release of calcium from bone tissue into blood
Parathyroid gland
4 small glands
Parathyroid hormones
Parathyroid hormones (PTH)
aka parathormone
targets bones, intestines, kidneys
increases blood calcium levels
Adrenal glands
above each kidney
aka suprarenal glands
made up of cortex and medulla
hormones of adrenal cortex
mineralcorticoids
glucocorticoids
Gonadocorticoids
Mineralcorticoids
most common is aldosterone
targets kidneys
regulates water balance in body
Glucocorticoids
most common is cortisol
targets most cells
increase blood sugar
inhibit inflammation and immune response
Gonadocorticoids
aka androgens
targets ovaries and testicles
increases sex drive
Hormones secreted by adrenal medulla
Epinephrine
Norepinephrine
Epinephrine
aka adrenaline
targets heart and blood vessels
Coping with stress by increasing heart rate, blood pressure, blood flow to skeletal muscles and blood sugar
Norepinephrine
aka noradrenaline
targets heart and blood vessels
raises blood pressure
Hormones produced by panceas
insulin
glucagon
Insulin
produced by beta cells in islets of langerhans
Targets most cells
Lowers blood glucose by increasing rate of glucose transported into cells
Glucagon
produced by alpha cells int he islets of langerhans
Targets liver
increases blood glucose
stimulates live to convert glycogen into the bloodstream
Male Gonads
testicles which produce testosterones
Female gonads
ovaries with produce estrogen (female characteristics) and progesterone (Maintain lining of uterus for pregnancy)
Thymus gland
site production of t cells (immunity) Secretes thymosin (regulates development and function of immune system)
Pineal Gland
Affects rate of secretion of other hormones
Secretes melatonin
Other organs that produce hormones
stomach (gastrin stimulates release of HCl for digestion)
Duodenum (secretes intestinal gastrin which inhibits HCl)
Kidneys (Erythropoietin EPO stimulates bone marrow to produce RBC)
Skin (cholecalciferol stimulates active transport of calcium into bloodstream)
Adipose tissue (leptin suppresses appetite)
Heart (atrial natruretic peptide)
