endocrine system Flashcards
endocrine system
cells, tissues, and organs that secrete hormones as a primary or secondary function and play an integral role in normal bodily processes
paracrine
chemical signaling that elicits a response in neighboring cells
autocrine
chemical signaling acts on the same cell that secreted it
hormones
secretion of an endocrine organ that travels via the bloodstream or lymphatics to induced a response in target cells or tx in another part of the body
peptides hormones
water soluble, lipophobic
exert action via receptor on cell membrane
steroid hormones
water insoluble, lipophilic
exert action intracellularly
hypothalamus posterior lobe
hypothalamus————hormone
anterior lobe (hypothalamus)
hypothalamus— releasign factor—- endocrine cells
oxytocin
posterior hypothalamus
stimulated by
cervical stretch during birthing
suckling
physical affection
effects:
Increase intracellular Ca+ - Increase strength of contraction
Breast milk ejection “milk letdown reflex”
Male ejaculation
“Cuddle hormone” - love / affection/compassion
ADH
Stimulated by:
Low Blood Pressure ( through Angtiotensin II)
High Blood osmolality
Effects:
Increased water reabsorption in the kidney at the site of the collecting duct.
Systemic Vasoconstriction
growth hormone
*anterior pituitary
Stimulated by: Hypothalamus – Growth hormone releasing hormone In Response to: High amino acid levels Hypoglycemia Low fatty acid levels Exercise
Effects:
Raises blood glucose
Stimulates Liver for production and release of Insulin like Growth Factor
Stimulates Liver - Gluconeogensis (glucose from non carbohydrate sources)
Lipolysis
insulin like growth factor (anterior)
muscle
hypertrophy of muscle
results in absorption of amino acids to muscle cells.
bone
endochondrial ossification- bones become harder/ thicker
both osteoblast and osteoclasts activity
Epiphyseal plate proliferation (bone growth) through Cartilage proliferation/differentiation
acromegaly
disorder of IGF which causes excessive growth of the hands, feet, jaw and internal organs in adulthood
gigantism
abnormal hogh linear growth excesive action IGF before closure of the epiphyseal growth before adulthood
prolactin
normally inhibited by dopamine (normal state) stimulated by pregnancy through thyrotropin releasing hormone estrogen breastfeeding effects- milk production
thyroid stimulating hormone
Stimulated by:
Thyrotropin releasing hormone (released by Hypothalamus) stimulates Thyrotropes in pituitary
Cold Temp
Pregnancy
Effects:
Transcription within thyroid to release thyroglobulin
Enzymatically bound to Iodine to produce:
Thyroxine (T4)
Triiodothyronine (T3) – is the active form in the cell
Together are “Thyroid hormone”
Acts like steroid – can pass phospholipid layer of cells
Within the cell it acts together with retinoic acid to increase transcription of protein that are metabolically active
thyroid hormone (T3 + T4) effects
Liver Glycogenolysis Glucneogenisis Lower LDL in blood Heart Upregulates B1 receptor Increase Contractility Increase Rate CNS Increases dendrite formation Increase mylenation (faster transmission) Improve connectivity Bone Regulates balance of Resorption/deposition Growth at epiphyseal plates Endochondrial ossification (hardening) Adipose Tissue Increases Lipolysis
Capillary dilation – heat regulation
Increase sweat production
(In hypothroidsim – may have thin and brittle nails and hair)
GI tract
Increases motility
Increases secretion of digestive enzymes/ mucous
Muscles
Regulates Catabolism/Anabolism
(in hyperthyroidism shifts towards catabolism)
parathyroid hormone (PTH)
Parathyroid hormone is released by “Chief Cells” in the parathyroid gland
Stimulated by low blood calcium
Effects:
Increase bone resorption (increase Ca+ to blood)
Calcium reabsorption from urine filtrate
Upregulates enzyme that activates vitamin D in the kidney
Vitamin D in turn - Upregulates Ca+ absorption in GI tract
calcitonin (PT)
Stimulated High blood calcium
Released by Parafolicular cell in the thyroid
Effects:
Inhibits Osteoclasts – Net bone deposition increases
Aldosterone
adrenal glands
Made in the Zona Glomerulosa of adrenal glands
Made in the Zona Glomerulosa of adrenal glands
Stimulated by: Angiotensin II Hyponatremia/ Hyperkalemia Adrenal Corticotropic Hormone (ACTH) Effects: Upregulates Na+ resorption in distal convoluted tubule Water follow Na+
cortisol * adrenal glands
“Stress hormone”
made in Zona Fosiculata of Adrenal Gland
Stimulated by: Hypoglycemia Chronic stress Muscle: Protein Catabolism – Amino acids released to blood Bone: Protein Catabolism from cartilage Adipose Lipolysis - glycerol to blood stream Liver Gluconeogenesis – Glucose formation from non-carbohydrate sources Glycogenolysis (indirect effect) – more glucose
progesterone
made in ovaries
stimulates uterus- regulates menstruation
catecholamines
made in adrenal medulla
Stimulated by “Fight and Flight”
Short term stress
Actually synthesized in specialized nerve cell call chrommafin cells
Tyrosine gets converted to Epinephrine and Nor-epinephrine
glucagon (pancreas)
glucagon
manufactured by alpha cells
stimulated by Hypoglycemia, sympathetic stimulation
insulin (pancreas)
Made by Beta Cells in pancreas
Stimulated by Hyperglycemia
Effects:
Liver: Glycogenesis
Muscles: Amino acid uptake Protein synthesis Glucose uptake Adipose tissue Inhibits lipase Lipogenesis
pineal gland
Regulates sleep – wake cycle
Produces melatonin; highest at night
Effects: Resets biological clock
Suprachiasmatic nucleus
chorionic gonatropin hormone
used in pregnancy
