Unit 2 Endocrinology Flashcards
Adipose Tissue
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Leptin
Primary Target Organs: Hypothalamus
Primary Effects: Suppress Appetite
Adrenal Cortex
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: (Major Hormones, Primary Target Organs, and Primary Effects)
Primary Target Organs: Liver and Muscles, Kidneys
Primary Effects: Glucocorticoids influence glucose metabolism; mineralocorticoids promote Na+ retention, K+ excretion
Adrenal Medulla
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Epinephrine
Primary Target Organs: Heart, Bronchioles, Blood Vessels
Primary Effects: Causes Adrenergic Stimulation
Heart
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Atria Natriuretic Hormone
Primary Target Organs: Kidneys
Primary Effects: Promotes Excretion of Na+ and Water in Urine
Hypothalamus
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Releasing and Inhibiting Hormones
Primary Target Organs: Anterior Pituitary
Primary Effects: Regulates secretion of anterior pituitary hormones
Small Intestine
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Secretin and Cholecystokinin
Primary Target Organs: Stomach, Liver, Pancreas
Primary Effects: Inhibits gastric motility and stimulates bile and pancreatic juice secretion
Islets of Langerhans (pancreas)
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Insulin Glucagon
Primary Target Organs: Liver, skeletal muscle, and adipose tissue primarily
Primary Effects: Insulin promotes cellular uptake of glucose and formation of glycogen and fat; glucagon stimulates hydrolysis of glycogen and fat
Kidneys
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Erythropoietin
Primary Target Organs: Bone Marrow
Primary Effects: Stimulates Red Blood Cell Production
Liver
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Somatomedins
Primary Target Organs: Cartilage
Primary Effects: Stimulates Cell Division and Growth
Ovaries
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Estradiol 17-B, Progesterone
Primary Target Organs: Female reproductive tract and mammary glands
Primary Effects: Maintains structure of reproductive tract and promotes secondary sex characteristics
Parathyroid Glands
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Parathyroid Hormone
Primary Target Organs: Bone, Small Intestine, and Kidneys
Primary Effects: Increases Ca2+ Concentration in blood
Pineal Gland
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Melatonin
Primary Target Organs: Hypothalamus and Anterior Pituitary
Primary Effects: Affects Secretion of Gonadotrophic Hormones
Pituitary , Anterior
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Trophic Hormones
Primary Target Organs: Endocrine Glands and Other Organs
Primary Effects: Stimulates growth and development of target organs; stimulates secretion of other hormones
Pituitary, Posterior
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Antidiuretic Hormone Oxytocin
Primary Target Organs: Stimulates growth and development of target organs; stimulates secretion of other hormones
Primary Effects: Antidiuretic hormone promotes water retention and vasoconstriction; oxytocin stimulates contraction of uterus and mammary secretory units, promoting milk ejection
Skin
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: 1,25-Dihydroxyvitamin D3
Primary Target Organs: Small Intestine
Primary Effects: Stimulates absorption of Ca2+
Stomach
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Gastrin
Primary Target Organs: Stomach
Primary Effects: Stimulates Acid Secretion
Testes
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Testosterone
Primary Target Organs: Prostate, seminal vesicles, testes, and other organs
Primary Effects: Stimulates secondary sexual development, spermatogenesis, other effects
Thymus
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Thymopoietin
Primary Target Organs: Lymph Nodes
Primary Effects: Stimulates White Blood Cell Production
Thyroid Gland
Major Hormones, Primary Target Organs, and Primary Effects
Major Hormone: Thyroxine (T4) and triiodothyronine (T3); calcitonin
Primary Target Organs: Most Organs
Primary Effects: Thyroxine and triiodothyronine promote growth and development and stimulate basal rate of cell respiration (basal metabolic rate or BMR); calcitonin may participate in the regulation of blood Ca2+ levels
Endocrine Glands
Glands that secrete Hormones into the circulation rather than into a duct
Hormone
A regulatory chemical produced in an endocrine gland that is secreted into the blood and carried to the target cells that respond to it by an alteration in their metabolism
Amines
Hormones derived from the amino acids tyrosine and tryptophan. They include the hormones secreted by the adrenal medulla, thyroid, and pineal glands.
Glycoproteins
a protein bound to one or more carbohydrate groups. Examples are follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
Steroids
Steroid hormones are derived from cholesterol after an enzyme cleaves off the side chain attached to the five-carbon “D” ring (fig. 11.2). Steroid hormones include testosterone, estradiol, progesterone, and cortisol.
Divisions of the Autonomic Nervous System
Sympathetic and Parasympathetic
Sympathetic Nervous System mediates
Fight or Flight
Parasympathetic Nervous System mediates
Rest and Digest
The Sympathetic Division is located in
The thoracolumbar Division
Adrenal Medulla’s Secretory cells appear to be modified
Postganglionics
Adrenal medula releases
85% Epinephrine and
15% NorEpinephrine
In response to preganglionic stimulation
How is Epinephrine made?
By Methylating Norepinephrine
The Parasympathetic Division is located
In the Craniosacral Division
What nerve carries most parasympathetic fibers
Vagus Nerve
Postganglionic Synapses have unusual Synapses called
Varicosities
Adrenergic Stimulation
Causes both excitation and inhibition depending on tissue
What are the two types of Adrenergic Receptors?
Alpha and Beta
Alpha 1, Alpha 2) (Beta 1, Beta 2
Adrenergic effects of the Eye
Contraction of radial Fibers of the Iris dilates the pupils. (Alpha 1)
Adrenergic Effects of the Heart
Increase Heart Rate and Contraction Strength (Beta 1)
Adrenergic Effects of Skin and Visceral Vessels
Arterioles Constrict due to smooth muscle contractions ( Alpha 1)
Adrenergic Effects of Skeletal Muscle Vessels
Arterioles constrict due to sympathetic nerve activity (Alpha 1)
Arterioles dilate due to Epinephrine ( Beta 2)
Adrenergic Effects of the Lungs
Bronchioles (Airways) dilate due to smooth muscle relaxation (Beta 2)
Adrenergic Effects of Stomach and Intestines
Contraction of Sphincters slows passage of food (Alpha 1)
Adrenergic Effects of the Liver
Glycogenolysis and secretion of Glucose (Alpha 1, Beta 1)
Cholinergic Synapses have 2 subtypes:
Nicotinic and Muscarinic
Nicotinic Receptors are stimulated by ____ and Blocked by____
Nicotine
Curare
Muscarinic Receptors are stimulated by ____ and Blocked by ______
Muscarine (From poisonous mushrooms)
Atropine
Nicotinic Ach Receptors Are Found
In the postsynaptic membrane of All Autonomic Ganglia, , All NMJs, and Some CNS pathways
Muscarinic ACh Receptors
Produce parasympathetic nerve effects in the heart, smooth muscles, and glands,
GPCRs (Receptors influence ion channels by means of G-Protein)
Skeletal Muscle response to Acetylcholine
Depolarization, producing action potentials and muscle contractions.
Ach opens cation channel in receptor (Ca2+)
Autonomic Ganglia response to Acetlycholine
Depolarization, causing activation of postganglionic neurons
Ach opens cation channel in receptor
Smooth Muscle Gland response to Acetylcholine
Depolarization and contraction of smooth muscle, secretion of glands
Ach activates GPCR , opening Ca2+ , channels and increasing cytosolic Ca2+
Heart response of Acetylcholine
Hyperpolarization, slowing rate of spontaneous depolarization
Ach activates GPCR , Opening K+ Channels
Dual Innervation
Most visceral organs receive dual innervation (supplied by both Symp and Parasymp)
Ways Dual Innervation can affect the body
Can be Complementary, Cooperative
Organs without dual innervation
Regulation is achieved by increasing or decreasing firing rate
E.g. adrenal medulla, arrector pili muscle, sweat glands, and most blood vessels receive only sympathetic innervation
What directly controls the activity of the ANS
Medulla Oblongata (Most Directly)
What other areas of the brain control activity of the ANS
Hypothalamus
Limbic System
Cerebral Cortex
Cerebellum
The hypothalamus has both neural functions and _____
Releases Hormones
Besides the Hypothalamus, what are the organs that produce hormones?
Adipose Cells, Pockets of cells in the walls of the small intestine, stomach, Kidneys, and Heart
Hormones
Chemical Substances secreted by cells int the extracellular Fluid (Blood)
Functions of Hormones
Regulate metabolic functions of other cells
Hormones have lag times ranging from
Seconds to hours
Hormones are classified as
Amino-Acid Based hormones, or Steroids
Amino Aid Based Hormones
Amines, Thyroxine, Peptide, and Protein Hormones
Hormones alter target cells activity by 2 mechanisms:
Second Messeners
Direct Gene Activation
Second Messenger Target cell activity mechanisms
Regulatory G Proteins
Amino-Acid Based Hormones
Direct Gene Activation activity mechanisms
Steroid Hormones
Hormones produce what kind of cellular changes:
Plasma membrane permeabilty Stimulate protein synthesis Activate/Deactivate enzyme systems Induce Secretory activity Stimulate Mitosis
What is an example of a Second Messenger?
Cyclic AMP: cAMP
PIP-Calcium
True or False: Steroid hormones and thyroid hormone diffuse easily into their target cells
True
Once steroid Hormones are inside the cell, what occurs?
They Bind and activate a specific intracellular receptor
Hormones circulate to all tissues but only activate cells called
Target Cells
Target cells have
Specific Receptors
Receptors may be intracellular or
Located on the Target Membrane
Target Cell Activation depends on three factors
Blood levels of the hormone
The relative number of receptors on the target cell
The affinity of those receptors for the hormone
Hormones circulate in the blood in 2 forms:
Free or Bound
Are steroid Hormones Free or Bound?
Steroids and Thyroid hormones are attached to plasma Proteins
Besides Steroid and Thyroid Hormones, what type are all other hormones?
All others are free
Concentration of circulating hormones reflect
Rate of release
Speed of inactivation and removal from the body
Horones are released from the blood by
Degrading enzymes
The kidneys
Liver enzyme systems
What are the three types of hormone Interaction?
Permissiveness
Synergism
Antagonism
Blood levels of hormones are controlled by
Negative Feedback Systems
Hormones are synthesized and released in response to
Humoral stimuli
Neural stimuli
Hormonal stimuli
Humoral Stimuli
secretion of hormones in direct response to changing blood levels of ions and nutrients
Humoral Stimuli
secretion of hormones in direct response to changing blood levels of ions and nutrients
Example of Humoral Stimuli
Concentration of Ca2+ Ions in the blood
Declining blood Calcium concentration stimulates the parathyroid gland to secrete
PTH Parathyroid Hormones
PTH causes
Ca2+ concentrations to rise and the stimulus is removed
Neural Stimuli
nerve fibers stimulate hormone release
Preganglionic Sympathetic Nervous System fibers stimulate
the adrenal medulla to secrete catecholamines
Hormonal Stimuli
release of hormones in response to hormones produced by other endocrine organs
They Hypothalamic hormones stimulate
The Anterior Pituitary
Pituitary Hormones stimulate targets to
Secrete more hormones
Anterior Pituitary Hormones
Tropic hormones that target other endocrine glands
What do Gonadotropins do?
Target gonads
Examples of Gonadotropins
FSH (Follicle Stimulating Hormone)
LH (Luteinizing hormone)
Tropic Hormone Examples
Gonadotropins TSH (Thyroid Stimulating Hormone) ACTH (adrenocorticotropic hormone) PRL (Prolactin) GH (Growth Hormone)
Leutinizing hormone affects what areas?
Testes
Ovary
TSH affects what area
Thyroid Gland
Prolacta affects what area
Mammary Glands
Growth Hormone affects what areas?
Liver
IGF
Fat Muscle Bone
ACTCH (Adrenocorticotropic Hormone) affects what areas?
Adrenal Cortex
Pituitary Hormones
Oxytocin
ADH
FSH Stimulates
Production of egg or sperm cells
LH function
Stimulates Hormone Production
LH Function in females
stimulates ovulation and corpus luteum to secrete progesterone and estrogen
LH function in males
stimulates interstitial cells of testes to secrete testosterone
TSH Function
Stimulates growth of gland and stimulation of TH
ACTCH (Adrenocorticotropic Hormone) function
Regulates response to stress, stimulates adrenal cortex
Prolacta function in females
Milk Synthesis after delivery
Prolacta function in males
increases Leutinizing hormone sensitivity, thus increases testosterone secretion
How is the Anterior Pituitary Gland controlled?
releasing hormones and inhibiting hormones of hypothalamus
How is the Posterior Pituitary Gland Controlled?
Neuroendocrine Reflexes
hormone release in response to nervous system signals
suckling infant ->stimulates nerve endings -> hypothalamus -> posterior lobe -> oxytocin -> milk ejection
hormone release in response to higher brain centers
milk ejection reflex can be triggered by a baby’s cry
Pineal Gland Function
Produces Serotonin in the daytime; Converts it to melatonin at night
Pineal Gland Function
Produces Serotonin in the daytime; Converts it to melatonin at night
Thymus function
regulate development and later activation of T-lymphocytes
*thymopoietin and thymosins
Thyroid Gland
Largest endocrine gland; high rate of blood flow
arises root of embryonic tongue
What homones are released by the Thyroid Gland?
T3, T4, Thyroid Hormone
C Cells
Calcitonin or Parafollicular cells
Produce Calcitonin
Parathyroid Gland releases
Parathyroid Hormone
Adrenal Medulla
Sympathetic ganglion innervated by sympathetic preganglionic fibers
stimulation causes release of catecholamines (epinephrine, NE)
Adrenal Medulla’s Hormonal effect is longer lasting due to:
Increases alertness, anxiety, or fear increases BP, heart rate and air flow raises metabolic rate inhibits insulin secretion stimulates gluconeogenesis and glycogenolysis
What are the layers of the adrenal Cortex
Zona Glomerulosa (Outer) Zona Fasciulata (Middle) Zona Reticularis (Inner)
Sex Steroids are associated with what layer of the adrenal cortex?
(Zona Reticularis)
Androgen and Estrogen
Glucocorticoids are associated with what layer of the adrenal cortex
Zona Fasciulata
especially cortisol, stimulates fat and protein catabolism, gluconeogenesis (from a.a.’s and FA’s) and release of fatty acids and glucose into the blood
Mineralocorticoids are associated with what layer of the adrenal cortex?
Zona Glomerulosa
control electrolyte balance, aldosterone promotes Na+ retention and K+ excretion
Glucocorticoids, Mineralocorticoids, and Sex Steroids are all forms of
Corticosteroids
Pancreatic Hormones
Insulin
Glucagon
Somatostatin
Somatostatin comes from what type of cells
(From Delta (S) cells)