Note Taking Guide Capter 13: The Endocrine System
Exocrine vs. Endocrine glands
Endocrine secretions
Paracrine secretions
Autocrine secretions
Comparison of the nervous and endocrine systems
mechanisms
response time
duration
Hormones
Target cells and receptors
Chemistry of hormones
steroids
formed from cholesterol
biogenic amines
peptides or proteins
eicosanoids
based on arachidonic acid
prostaglandins
leukotrienes
Administration of hormones
Mechanisms of action
Lipid soluble hormones
Water soluble hormones
second messengers
cyclic AMP
amplify the effect of hormones
Prostaglandins
paracrines
produced as needed
Control of hormonal secretions
levels depend on increased or decreased secretion
tropic hormones
respond to internal environment
stimulation the nervous system
Suggested note card information:
Hormone produced by Target Effect Regulation
Hypothalamus and Pituitary gland (hypophysis)
Location
Posterior pituitary gland (neurohypophsis)
stores hormones made by hypothalamus
Oxytocin
labor contractions - positive feedback
milk "let down" (not production)
ADH - antidiuretic hormone (vasopressin)
makes distal convoluted tubules and collecting ducts permeable to water
lack of ADH - diabetes insipidus
Anterior Pituitary gland (adenohypophysis)
Controlled by inhibiting and
releasing hormones from the hypothalamus via hypophyseal portal veins.
Human growth hormone hGH or somatotropin
Prolactin (PRL)
Thyroid stimulating hormone
Adrenocorticotropic hormone - ACTH
Melanocyte-stimulating hormone - MSH
Follicle stimulating hormone - FSH
Leuteinizing hormone - LH (formerly ICSH in males)
Human Growth hormone:
protein
Effects:
1) stimulates protein synthesis and inhibits protein breakdown
2) stimulates lipolysis
3) slows breakdown of glucose (increases blood glucose levels)
Controlled by factors from hypothalamus
Imbalances:
pituitary dwarfism
gigantism
acromegaly
Released in diurnal rhythm
Prolactin
Breast development and lactation
Controlled by factors from hypothalamus
In males, deceases the secretion of LH
Thyroid stimulating hormone (thyrotropin)
Stimulates the thyroid gland to make hormones
Controlled by factors from hypothalamus and external factors
Adrenocorticotropic hormone (ACTH)
Acts on adrenal cortex
increased production of hormones, esp. cortisol
Controlled by factors from hypothalamus and any type of physiological stress
Follicle Stimulating hormone
Female: development of ovum and estrogen secretion by follicle
Male: stimulates the growth of seminiferous tubules
Controlled by factors from hypothalamus and estrogen and testosterone
Leuteinizing hormone
Female: development of follicle and ovulation, formation of corpus luteum
Male: stimulates interstitial cells to produce testosterone
Controlled by factors from hypothalamus
Melanocyte stimulating hormone(MSH)
Increase in melanin - may play a role in learning
Thyroid gland
Location
thyroxine or tetraiodothyronine T4 and triiodothyronine T3
stored in colloid in follicles
requires iodine
controls basal metabolic rate
Hypersecretion:
Grave’s disease
goiter
Hyposecretion:
Hashimoto’s disease
creatinism
Myxedema
Calcitonin
lowers blood calcium levels
inhibits osteoclasts
increased excretion of Ca and phosphate by kidney
no clinical deficiency symptoms as long as parathyroid is functional
Parathyroid glands
Location
parathyroid hormone (parathormone)
increases actions of osteoclasts
stimulates kidney to reabsorb calcium and lose phosphate
Controlled by blood calcium levels
hyposecretion -tetany and seizures
hypersecretion - osteitis fibrosa cystica
Adrenal Glands
Adrenal cortex
Zona glomerulosa
mineralocorticoids - aldosterone
retains sodium and water
loses potassium and H+
control by blood K+ levels and renin-angiotensin pathway
Zona fasciculata
glucocorticoids - cortisol
increased protein catabolism (breakdown) and decreased synthesis
lipolysis
gluconeogenesis
resistance to stress
anti-inflammatory effects
depression of immune response
control
hyposecretion- Addison’s disease
hypersecretion - Cushing’s syndrome
Zona reticularis
androgens
Adrenal Medulla
chromaffin cells - sympathetic postganglionic cells
epinephrine - 80%
norepinephrine- 20%
tumors- pheochromocytomas
Pancreas
islets of Langerhans
alpha cells - glucagon
increases blood glucose levels
beta cells - insulin
decreases blood glucose levels
increases faciliatated diffusion into cells
increases formation of glycogen
decreases gylcogenolysis and gluconeogenesis
diabetes mellitus - type I and type II
delta cells - growth hormone inhibiting hormone or somatostatin
Pineal gland ("Third eye")
Location
melatonin
circadian rhythms
onset of puberty?
Thymus gland
location
thymosin
Kidneys
erythropoietin
calcitriol
Digestive glands
enteroendocrine cells produce hormones that influence secretion and motility of GI tract
Heart
atrial natriuretic peptide (ANH)
Na+ and water losing hormone