Endocrine System Flashcards
Horomone
A chemical ligand or signal that travels a distance through the bloodstream in order to stimulate a response in target cells, tissues, or organs
4 Avenues of Cell Communication
- Gap Junctions
- Hormones
- Neurotransmitters
- Paracrines
Endocrine VS Nervous
Nervous
- communicates with neurotransmitters
- Localized effects
- stops when stimuli stops
- reacts within milliseconds
Endocrine
- communicates with hormones
- generalized widespread effect
- lingers after stimuli stops
- reacts slower to stimuli
Endocrine VS Exocrine
Endocrine
- Ductless
- secrete into bloodstream
- intracellular effects
- fenestrated capillaries
Exocrine
- ducts
- secrete out to epithelial surface
- extracellular
- no fenestrated capillaries
Steroid Hormones
Estrogen Testosterone Cortisol Aldosterone Vitamin D
Non-steroid Hormones
Amines ( Norepinepherine , epinephrine )
Proteins (PTH, GH, PRL)
Peptides (ADH,OT,TRH,SS,GnRH)
Glycoproteins (FSH,LH,TSH)
Intracellular Chemical Signals that AREN’T hormones
Autocrines, Paracrines, Pheromones, Neurohormone, Nuerotransmitter or neuromodulator
TRH (Thyrotropin-releasing hormone)
Released by: Hypothalamus
Effects: Promotes secretion of TSH (thyroid-stimulating hormone) AND PRL (prolactin)
GnRH (Gonadotropin-releasing hormone)
Released by: Hypothalamus
Effects: promotes secretion of follicle-stimulating hormone (FSH) and Luteinizing Hormone (LH)
Corticotropin-Releasing Hormone (CRH)
Released by: Hypothalamus
Effects: Promotes secretion of adrenocoritcotropic hormone (ACTH)
Growth Hormone Releasing Hormone (GHRH)
Released by: Hypothalamus
Effects: promotes secreting of growth hormone (GH)
Oxytocin (OT)
Released by: Posterior pituitary
Effects: labor contractions, milk release
Antidiuretic Hormone (ADH)
Released by: Posterior pituitary
Effects: water retention
How is secretion rate regulated ?
1) action of a substance other than a hormone on an endocrine gland (insulin production)
2) Neural control of endocrine (epinephrine)
3) Control of secretory activity of one endocrine gland by hormone or neurohormone (TRH->TSH->T3 & T4->TRH)
What regulates anterior pituitary secretions?
HYPOTHALAMUS
What controls posterior pituitary secretions?
NEUROENDOCRINE REFLEXES
Melatonin
Released by: Pineal Gland
Effects: Circadian Rhythm Control
What protein stores large amounts of thyroid hormone and where?
-Thyrogloubin
In the thyroid gland
What is the mineralcorticoid hormone
Aldosterone
What are the cells between follicles and what do they secrete?>
Parafollicular cells ; calcitonin
Thyroid Hormones
- T3 (Triiodothyronine, 10%)
- T4 (Tetraiodothyronine or Thyroxine, 90%)
Formed in the LUMEN
Follicles of thyroid contain thyroglobulin
Parathyroid Glands are made up of what types of cells
OXYPHILS
CHIEF CELLS - secrete parathyroid or parathormone (PTH)
- regulates Calcium levels
- stimulates osteoclasts activity in bone
Target: Bone, Kidneys, and Intestines
What hormone is essential for neuromuscular and cardiovascular function?
Parathormone , Parathyroid hormone , or PTH
3 Layers of Adrenal Cortex
- Zona glomuerulosa : (globs) small clusters of cells
- Zona Fasciculata : thickest layer made of columns or fascicles
- Zona Reticularis : deepest layer (net like)
What are secretions of the adrenal medulla controlled by
SYMPATHETIC PREGANGLIONIC NERVE FIBERS
Which cells release catecholamines (epinephrine, norepinephrine, and a trace of dopamine)
Chromaffin cells
5 Most important corticosteroid subcategories and their function
Mineralocorticoids: Regulate electrolyte balance
(ALDOSTERONE)
(Salt)
Glucocorticoids: regulate metabolism of glucose and other organic fuels
(Sugar)
Androgens: (Sex) developmental and reproductive functions
What is secreted by the zona glomerulosa?
Aldosterone which is regulated by decreasing the blood pressure
What is secreted by the zona fasciculata?
Glucocorticoids and androgens which are regulated by ACTH
CORTISOL
What is secreted by the zona reticularis?
Dehydroepiandrosterone (DHEA)
Which organ functions as both endocrine and exocrine glands ?
Pancreas
Which hormones are important in the regulation of circulating glucose?
Pancreatic Hormones
What cells make up pancreatic islets?
Alpha (GLUCAGON), beta (INSULIN and AMYLIN), delta (SOMATOSTATIN)
What are the functions of Glucagon
Glycogenolysis (glycogen breakdown into glucose) and Gluconeogenesis (synthesis of glucose from fats and proteins
What hyperglycemic hormones increase glucose levels in the blood?
Growth Hormone Epinephrine Norepinephrine Cortisol Corticosterone
Insulin targets which tissues
Liver, adipose, muscle, and the safety center of the brain
What is the function of AMYLIN
It controls your apetite
What does the absence in insulin do to your body
Increases
- hunger
- urine volume (polyuria)
- blood glucose levels
- thirst (polydipsia)
What does the placenta secrete
Estrogen and progesterone that regulate pregnancy
What Endocrine function does your skin do
It converts chlolesterol like steroids into cholecalciferol (VITAMIN D PRECURSOR) using sunlight
Endocrine functions of the liver
Converts cholecalciferol into calcidol (hormone that stimulates calcium reg)
Secretes angiotesinogen Secretes erythropoietin (RBC PRODUCTION)
Which organs secrete erythropoeitin ?
Liver and Kidneys
What do fat cells secrete
Leptin (regulates apetite)
