Endocrine System II Flashcards
TSH (Thyroid Stimulating Hormone) Pathway
TSH secreted by Anterior Pituitary Gland
TSH reaches Thyroid Gland
Thyroid Gland secretes T3/T4
ACTH (Adrenocorticotropic Hormone) Pathway
ACTH secreted by Anterior Pituitary Gland
ACTH reaches adrenal gland
Adrenal Medulla secretes Epinephrine/Norepinephrine
Adrenal Cortex secretes Glucocorticoids
GH (Growth Hormone) Pathway
GH secreted by Anterior Pituitary Gland
GH reaches liver
Liver secretes Somatomedins
Somatomedins reach Bone/Muscle Tissues
PRL (Prolactin) Pathway
PRL secreted by Anterior Pituitary Gland
PRL reaches Mammary Gland
FSH (Follice Stimulating Hormone)/LH (Luteinizing Hormone) Pathway
FSH/LH secreted by Anterior Pituitary Gland
FSH/LH reach Ovaries/Testes
Ovaries secrete Estrogen, Progesterone and Inhibin
Testes secrete Testosterone/Inhibin
MSH (Melanocyte Stimulating Hormone) Pathway
MSH secreted by Anterior Pituitary Gland
MSH reach Melanocytes
Effects of Somatomedins
Stimulates tissue growth in skeletal muscle and cartilage
Increases Amino Acid uptake/protein synthesis
Effects of GH on Tissues
Stimulates cell division in epithelial/connective tissue
Stimulates triglyceride breakdown in adipocytes
Stimulates liver glycogen breakdown
ADH (Antidiuretic Hormone) Pathway
ADH secreted by Posterior Pituitary Gland
ADH reaches Kidneys
OXT (Oxytocin) Pathway
OXT secreted by Posterior Pituitary Gland
OXT reaches smooth muscle in prostate gland
OXT reaches uterine smooth muscle and mammary glands
Nervous Stimulation of Posterior Pituitary Gland
Sensory and Osmoreceptor Stimulation causes direct release of hormones
Pineal Gland Structure
Contains Neurons
Contains Pinealocytes
Melatonin Features
Secreted by Pinealocytes
Influences circadian rhythms
Antioxidant
Structure of Thyroid Gland
Anterior to thyroid cartilage of larynx
Two lobes connected by narrow isthmus
Function of Thyroid Gland
Stores and secretes thyroid hormones
Thyroxine (T3) and Triiodothyronine (T4)
6 Effects of Thyroid Hormones
Increases oxygen and energy consumption
Increases heart rate
Increases sensitivity to sympathetic stimulation
Stimulates red blood cell formation
Affects activity of other endocrine tissues
Increases bone turnover
Thyroid Follicle Features
Hollow Spheres lined by cuboidal epithelium surrounded by capillaries
Contains colloid (protein rich fluid)
C Cell Functions
Produces Calcitonin
Important in Calcium Homeostasis
Regulation of Calcium Ion Concentration using Calcitonin
Calcium levels rise in blood
Thyroid Gland produces calcitonin
Increased Excretion of calcium by kidneys
Blood calcium levels decline
Homeostasis achieved
Regulation of Calcium Ion Concentration using PTH
Calcium levels decrease in blood
Parathyroid glands secretes PTH
Increased reabsorption of calcium by kidneys
Blood calcium levels increase
Homeostasis achieved
Parathyroid Gland Features
Small Gland posterior of thyroid
Parathyroid cells produce PTH
PTH is released to increase serum calcium when levels decline
2 Sections of Adrenal Gland
Adrenal Cortex
Adrenal Medulla
Secretions of the Adrenal Gland
Cortex = Glucocorticoids
Medulla = Catecholamines
3 Sections of Adrenal Cortex
Zona Reticluaris
Zona Fascicluata
Zona Glomerulosa
Zona Reticularis Hormones
Secretes Androgens - steorid hormones
Zona Fasciculata Hormones
Secretes Glucorticoids - cortisol
Promotes glucose synthesis, fat and protein metabolism
Zona Glomerulosa Hormones
Mineralocorticoids - aldosterone
Affects electrolyte composition
Regulation of Blood Pressure and Volume
Blood Pressure and volume falls
Renal Blood Flow and O2 falls
Erythropoietin and Renin released
Increased RBC production
Blood pressure and volume rises
Homeostasis achieved
Cells in Pancreatic Islets
Alpha Cells - produce glucagon
Beta Cells - produce insulin
Blood Glucose Regulation using insulin
Blood Glucose Levels rise
Beta Cells secrete insulin
Increased Glucose Transport/glucose-glycogen conversion
Blood glucose levels decrease
Homeostasis achieved
Blood Glucose Regulation using glucagon
Blood Glucose Levels fall
Alpha cells secrete glucagon
Increased breakdown of glycogen to glucose
Blood Gluose Levels rise
Homeostasis Achieved
Effects of Diabeted Mellitus
Kidney Damage
Retinal Damage
Peripheral Nerve Damage
Increased Cardiovascular Disease Risk
Antagonistic Definition
Hormone with opposing effect
e.g. PTH and Calcitonin
Synergistic Definition
Hormone with additive effects
e.g. GH and Glucocorticoids
Permissive Definition
One hormone is necessary for another to produce an effect
Integrative Definition
Hormones produce different but complementary results
5 Hormones needed for Normal Growth
GH - protein synthesis/cellular growth
Thyroid - nervous system development
Insulin - supply of energy and nutrients
Parathyroid - calcium absorption
Reproductive Hormones - cell growth/differentiation
Organs with secondary endocrine function
Heart - secretes natriuretic peptides to reduce blood pressure
Thymus - secretes thymosins to promote lymphocyte development
Adipose Tissue - Secretes leptin to suppress appetite
Stages of Fight of Flight from Adrenaline
Mobilization of glucose reserves
Changes in circulation
Increases in heart and respiratory rates
Increased energy use by all cells
