Chapter 10 Endocrine System Flashcards
Endocrine System
glands secrete hormones
Glands are ductless
Hormones exert specific effects on target organs
Amines
structural variation of amino acid tyrosine
includes Thyroxine, epinephrine and norepinephrine
Proteins
Chain of 50-200 amino acids
includes insulin, growth hormone and calcitonin
Steroids
Cholesterol is the precursor
includes cortisol, aldosterone, estrogen, testosterone, and progesterone
Regulation of hormone secretion
negative feedback back mechanism- info about hormone effects are fed back to the gland
The pituitary gland
two major portions is: posterior pituitary gland and the anterior pituitary gland
What are the hormones in Posterior Pituitary Gland?
2 hormones: antidiuretic and oxytocin
Antidiuretic Hormone (ADH or vasopressin)
Function:
•Increases water reabsorption by the kidney tubules (water returns to the blood)
•decreases sweating
•causes vasoconstriction (in large amounts)
Regulation: Decreased water in content in the body
Oxytocin
Functions:
•Promotes contraction of myometrium of uterus (labor)
•promotes release of milk from mammary glands
Regulation:
•Nerve impulses from hypothalamus the result of stretching of cervix or stimulation of nipple
•secretion from placenta at end of gestation-stimulus unknown
What are the hormones of the anterior pituitary gland?
Growth hormone
thyroid stimulating hormone
adrenocorticotropic hormone
prolactin
follicle-stimulating hormone
luteinizing hormone
Growth Hormone
Function:
•Increases rate for mitosis
•increases amino acid transport into cells
•increases rate of protein synthesis
•increases use of fats for energy
Regulation of secretion:
GHRH (hypothalamus) stimulates secretion
GHIH-somatostatin (hypothalamus) inhibits secretion
Thyroid-stimulating (TSH)
Function:
•Increases secretion of thyroxine and T3 by thyroid gland
Regulation of secretion:
TRH (hypothalamus)
Adrenocorticotrophic hormone (ACTH)
Function:
•Increases secretion of cortisol by the adrenal cortex
Regulation of secretion:
CRH (Hypothalamus)
Prolactin
Function:
•Stimulates milk production by the mammary glands
Regulation of secretion:
•PRH (hypothalamus) stimulates secretion
•PIH (hypothalamus) inhibits secretion
Follicle-Stimulating hormone (FSH)
Function:
In women-
• Initiates growth of ova in ovarian follicles
• Increases secretion of estrogen by follicle cells
In men-
• Initiates sperm production in the testes
Regulation:
•GNRH (hypothalamus) stimulus secretion
•Inhibin (ovaries or testes) inhibits secretion
Luteinizing hormone (LH) (ICSH)
Function:
In women-
• Causes ovulation
• Causes the ruptured ovarian follicle to become the corpus luteum
• Increases secretion of progesterone by the corpus luteum
In men-
• Increases secretion of testosterone by the interstitial cells in the testes
Regulation:
•GnRH (hypothalamus)
What are the hormones of the thyroid gland?
Thyroxine (T4) and (T3), Calcitonin
Thyroxine (T4) and triiodothyronine(T3)
Function:
•Increase energy production from all food types
• Increase rate of protein synthesis
Regulation:
TSH
Calcitonin
Function:
•Decreases the reabsorption of calcium and phosphate from bones to blood
Regulation:
•Hypercalcemia
Parathyroid glands
two on the back of each lobe of the thyroid gland
Produce parathyroid hormone
Parathyroid hormone
Function:
• Increases the reabsorption of calcium and phosphate from bone to blood
• Increases absorption of calcium and phosphate by the small intestine
• Increases the reabsorption of calcium and the excretion of phosphate by the kidneys; activates vitamin D
Regulation:
•Hypocalcemia stimulates secretion
•Hypercalcemia inhibits secretion
What are the hormones of the pancreas?
Glucagon
Insulin
Somatostatin (delta cells)
Glucagon (alpha cells)
Function:
• Increases conversion of glycogen to glucose in the liver
• Increases the use of fats and excess amino acids for energy
Regulation:
•Hypoglycemia
Insulin(Beta cells)
Function:
• Increases glucose transport into cells and the use of glucose for energy production
• Increases the conversion of excess glucose to glycogen in the liver and muscles
• Increases amino acid and fatty acid transport into cells, and their use in synthesis reactions
Regulation:
•Hyperglycemia
Somatostatin (delta cells)
Function:
•Decreases secretion of insulin and glucagon
• Slows absorption of nutrients
Regulation:
•Rising levels of insulin and glucagon
Adrenal Glands
consists of two parts: inner adrenal medulla, outer adrenal cortex
What are the hormones in Adrenal Medulla?
Norepinephrine, Epinephrine
Norepinephrine
Function:
• Causes vasoconstriction in skin, viscera, and skeletal muscles
Regulation:
•Sympathetic impulses from the hypothalamus
Epinephrine
Function:
• Increases heart rate and force of contraction
• Dilates bronchioles
• Decreases peristalsis
• Increases conversion of glycogen to glucose in the liver
• Causes vasodilation in skeletal muscles
• Causes vasoconstriction in skin and viscera
• Increases use of fats for energy
• Increases the rate of cell respiration
Regulation:
•Sympathetic impulses from the hypothalamus in stressful situations
What are the hormones in adrenal cortex?
Aldosterone, cortisol
Aldosterone
Function:
• Increases reabsorption of Na+ ions by the kidneys to the blood
• Increases excretion of K+ ions by the kidneys in urine
Regulation:
•Low blood Na+ level
•low blood volume or blood pressure
•high blood k+ level
Cortisol
Function:
• Increases use of fats and excess amino acids for energy
• Decreases use of glucose for energy (except for the brain)
• Increases conversion of glucose to glycogen in the liver
• Anti-inflammatory effect: stabilizes lysosomes and blocks the effects of histamine
Regulation:
ACTH (anterior pituitary) during physiological stress
