BIO Ch. 18/19 - Endocrine System Flashcards
Endocrine System Function
Contributes homeostasis:
- maintain proper balance of chemicals
- maintain harmonious fx/coordination of all
bodily processes/organ systems
Ductless glands that secrete hormones directly into bloodstream
Hormones
Work more slowly but have longer affects
Target specific organ/tissue or stimulate other glands
Endocrine Reflexes: negative feedback loop that controls hormone secretion
Integrator is the gland
Hormone Classification
By General fx:
- Tropic: target other endocrine glands to
stimulate their growth/secretion
- Sex: target reproductive tissues
- Anabolic: stimulates anabolism in target
cells
By Chemical structure:
- steroid: lipid soluble (from CHOL)
- testosterone, estrogen, cortisol,
aldosterone
- nonsteroid: water soluble (from amino
acids)
- protein & peptidesHypothalamus
Connects the NS and ENDO systems
Regulates Ant Pituitary Gland: stim/inhibits pituitary hormone production
Releases hormones directly into blood through the Post Pituitary Gland
Controls the ENDO cells of the Adrenal Gland
Hormones of Anterior Pituitary Gland
- Growth Hormones: controls growth rate of
skeletal/visceral structures, stimulates fat
metabolism - Prolactin: stimulates mammary glands to
produce milk (lactation) - Thyroid-stimulating Hormone (TSH):
increase thyroid activity = more secretion
of thyroid hormone - Adrenocorticotropic Hormone (ACTH):
stimulates adrenal cortex = more hormones - Follicle-stimulating Hormone (FSH):
stimulates development/activity of
structures that produce sperm or ovarian
follucle - Lutenizing Hormone (LH): secretes
hormones to aid in the development &
activities of the ovary/testes
Hormones of the Posterior Pituitary Gland
- Antidiuretic Hormone: conserves bodily
water by preventing urine formation;
triggered by dehydration- reabsorption of water in kidneys
- arginine vasopressin: contraction of
arteriole walls = incr BP
- Oxytocin: causes milk ejection & uterine
contraction during childbirth- controlled by positive feedback loop
Pineal Gland
Supports the body’s biological clock
Secretes Melatonin
Hormones of the Thyroid Gland
- Thyroid Hormone (T3/T4): increases
metabolic rate of all cells- Cretinism: low T3/T4 = low metabolic
rate
- Cretinism: low T3/T4 = low metabolic
- Calcitonin: removes Ca from blood for bone
formation (osteoblasts)
Parathyroid Gland
Secretes Parathyroid Hormone (PTH): primary
hormone to maintain Ca homeostasis
- stimulates bone reabsorption (osteoclasts)
causing incr blood Ca levels
- reabsorption of Ca in urine from kidneys
- reabsorption of Ca in intestine by incr
Vit-D
- decreases phosphate
Adrenal Glands
Adrenal Cortex: secretes corticosteroids
hormones
- Mineralocorticoids: regulate mineral salts
- Aldosterone: maintains Na homeostasis
by reabsorption in kidneys, incr water
retention, promotes loss of Ka/H
- Glucocorticoids: aid Epi/Norepi to cause
vasoconstriction for maintaining normal BP
- Gonadocorticoids: sex hormones released
Adrenal Medulla: secretes Epi/Norepi (catecholamines - nonsteroid)
Hormones of Pancreatic Islets
Islets of Langerhans
1. Glucagon: incr blood glucose (glycogen
conversion to glucose), stimulates
gluconeogenesis (fatty acids/amino acids
into glucose) in liver cells
2. Insulin: lowers glucose, amino acids, and
fatty acids to promote their metabolism
3. Somatostatin: regulates all hormones of the
pancreatic islet
4. Pancreatic Polypeptide: influence digestion
and distribution of food molecules
Male Gonads
Produce testosterone (androgen)
- growth/maintenance of male sexual
characteristics
Regulated by gonadotropin (from Ant Pituitary)Female Gonads
Estrogens: steroid hormone that promotes development/maint of female sexual characteristics
Progesterone:”pregnancy-promoting” hormone; maintains the lining of uterus
Regulated by the Ant Pituitary Gland
Placenta
Relaxin is produced to prepare body for childbirth
Thymus
Primarily a Lymphatic organ
Produces thymosin: stimulated T-cell
development for immunity
