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147 Cards in this Set
- Front
- Back
Mechanisms of Intercellular Communication (DIRECT)
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By ions via gap junctions (when cells are in contact w/each other)
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Mechanisms of Intercellular Communication (PARACRINE)
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By paracrine factors via the extracellular fluid (cells farther apart)
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Mechanisms of Intercellular Communication (ENDOCRINE)
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By hormones via the circulatory system (enters blood stream)
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Mechanisms of Intercellular Communication (SYNAPTIC)
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By neurotransmitters across synaptic clefts (carried by nerve endings - nervous system)
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Endocrine Glands
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-Hypothalamus
-Pituitary Gland -Thyroid Gland -Pineal Gland -Suprarenal Gland -Parathyroid Gland -Pancreas |
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Endocrine Tissues In Organs
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-Kidneys
-Heart -Intestines -Thymus -Gonads -Adipose Tissue |
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Hormones
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Chemical regulators of various body functions such as growth and reproduction
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Where are hormones secreted and and why are they transported?
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Blood; To affect the functions of their target cells
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What do hormones bind to?
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Specific receptors on their target cells
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What are hormones specific for?
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Certain target cells
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Steroids
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Derived from lipds or cholesterol
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Monoamines
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Derived from a single amino acid
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Oligopeptides
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Made from 3-10 amino acids
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Glycoproteins
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Carbohydrates/proteins complexes with α & β acid chains
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Polypeptides
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14-199 amino acids
*All other hormones |
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Hormone Secretion
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-Stimulus
-Gland {Hormone} *Hormone secretion goes into blood stream* -Blood -Receptor -Target Cells -Action |
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Hormone Receptors
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Protein molecules located on the cell membrane, cytoplasm, or nucleus
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Steroid Hormones
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Bind to nuclear receptors associated with DNA transcription
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Thyroid Hormones
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Bind to cytoplasmic receptors on mitochondria, ribosomes or nucleus
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All Other Hormones
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Bind to cell membrane receptors and activate second messenger systems
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Negative Feed Back
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Blood level of the endocrine gland hormone reach an optimum value, it inhibits secretion of the hypothalamic and anterior pituitary hormones that stimulate the gland
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Postive Feed Back
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The response to an endocrine gland hormone reach an optimum level, it increases secretion of the hormone that stimulates that response
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Hypothalamus
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A central area of the basal brain limbic system
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The hypothalamus consist of a large number of what?
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Nuclei
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What do the nuclei in the hypothalamus do?
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Modify and control the body functions via the hypothalamic hormones
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Hypothalamic Hormones
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-Growth hormone releasing hormone (GHRH)
-Growth Hormone Inhibiting Hormone (GHIH) - Somatostatin -Prolactin Releasing Hormone (PRH) -Prolactin Inhibiting Hormone (PIH) - Dopamine -Corticotopin Releasing Hormone (CRH) -Gonadotropin Releasing Hormone (GnRH) -Thyrotropin Releasing Hormone (TRH) -Antidiuretic Hormone (ADH) -Oxytocin (OT) |
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Corticotropin Releasing Hormone (CRH)
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Suprenal Gland
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Gonadotropin Releasing Hormone (GnRH)
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Gonads Gland
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Thyrotropin Releasing Hormone (TRH)
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Thyroid Gland
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Hypothalamic Hormones that are released from the hypothalamus
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-Growth hormone releasing hormone (GHRH)
-Growth Hormone Inhibiting Hormone (GHIH) - Somatostatin -Prolactin Releasing Hormone (PRH) -Prolactin Inhibiting Hormone (PIH) - Dopamine -Corticotopin Releasing Hormone (CRH) -Gonadotropin Releasing Hormone (GnRH) -Thyrotropin Releasing Hormone (TRH) |
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Hypothalamic Hormones that are released from the posterior pituitary
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-Antidiuretic Hormone (ADH)
-Oxytocin (OT) |
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Pituitary Gland
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A small gland that is connected to the hypothalamus by the infundibulum
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Anterior Pituitary (NAME)
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Adenohypophysus
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Posterior Pituitary (NAME)
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Neurohypophysis
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Posterior Pituitary
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Derived from neural brain tissue and connects to hypothalamus by the stalk-like hypothalamus hypophyseal tract
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Anterior Pituitary
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Derived from ectodermal tissue in the roof of the embyonic mouth and connects to the hypothalamic hypophyseal portal system
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Oxytocin (OT)
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-Target tissues are smooth muscles of reproductive systems of both females and males
-Stimulates uterine contractions during labor -Stimulates milk ejection during suckling -Stimulates semen propelling during ejaculation |
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Antidiuretic Hormone (ADH) - Vasopressin)
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-Target tissues are kidneys and blood vessels
-Increases water reabsorption in the kidneys to increase blood volume -Causes vasocontriction of blood vessels to increase blood pressure |
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Human Growth Hormone (hGH)
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-Targets all cells especially skeletal and muscle tissue
-Directly stimulates stem cells division and differentiation -Stimulates liver synthesis and release of somatomedins -Somatomedins indirectly mediates growth hormone functions by increasing protein synthesis and cell division -Results in growth to adulthood and maintenance of skeleton and muscles in adults |
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Pituitary Dwarfism
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Caused by hyposecretion in children and adolescents resulting in small body
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Gigantism
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Caused by hypersecretion in infants and children resulting in heigh of over 8 feet
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Acromegaly
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Caused by hypersecretion in adults resulting in distorted facial features
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Thyroid Stimulating Hormone (TSH)
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-Targets thyroid gland
-Stimulates secretion of the thyroid hormones |
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Adrenocorticotropic (ACTH)
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-Targets adrenal cortex
-Stimulates secretion of glucocorticoids from the adrenal cortex |
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Prolactin (PRL)
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-Targets mammary glands
-Stimulates milk synthesis in mammary glands |
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Gonadotropins
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-Follicle stimulating hormone (FSH)
-Luteinizing hormone (LH) -Target the ovaries -Control female and male reproductive physiology |
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What stimulates secretion?
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Releasing hormones (RH)
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Where are releasing hormones and inhibiting hormones released from?
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Hypothalamus through hypophyseal portal system
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What supresses secretion?
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Inhibiting hormones (IH)
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What controls the anterior pituitary hormone secretion and inhibition?
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Negative or positive feedback
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Thyroid Gland
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-Large butterfly-shaped gland in neck below voice box (larynx)-Has two lobes connected by an isthmus
-Made of follicles filled with a colloid |
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Thyroid Hormone Synthesis
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1. Iodide trapping by follicular cells and transport into follicular lumen
2. Synthesis of thyroglobulin by follicular cells and transport into follicular lumen 3. Oxidation of iodide to iodine in lumen by thyroid peroxidase enzyme 4. Iodination of tyrosine molecules in the thyroglobulin chain to form T1 and T2 5. Coupling of T1 and T2 to make T3 or T4 6. Pinocytosis of thyroglobulin chain by the follicular cells and digestion by lysosomal enzymes to produce free T3 and T4 7. Secretion of T3 (Triiodothyronine) and T4 (Tetraiodothyronine/Thyroxine) into the blood 8. Transport of T3 and T4 in blood in the free form or bound to thyroid-binding-globulin (TBG) |
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Parafollicular C cells
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Produce Calcitonin
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T3 & T4
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-Increase the basal metabolic Rate (BMR) of all cells
-Increase ATP production in mitochondria of all cells by aerobic cell respiration -Promote normal growth synergistically with growth hormone |
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Calcitonin
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Decreases blood calcium levels
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Thyroid Dwarfism (Cretinism)
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-Hypothyroidism during fetal development or early infancy
-Severe forms of mental and physical retardation in the newborn child -Retardation is reversible only if hormonal replacement therapy is started during the first four months of life |
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Hypothyroidsim (in adults)
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-Too little T3 & T4
-Symptoms: -Decreased basal metabolic rate -Bradycardia -Decreased body temperature -lethargy -goiter -weight gain -cold intolerance -myxedema |
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Hyperthyroidism (in adults)
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-Too much T3 & T4
-Grave's disease is the most common form -Symptoms: -Increased basal metabolic rate -Tachycardia -Increased body temperature -Anxiety & irritability -Goiter -Weight Loss -Heat intolerance -Exophthalmia (Exopthalmos) |
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Endemic Goiter
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-Caused by iodine deficiency
-Insufficient dietary iodine to make T3 & T4 -Occur mostly in arid, dry, inland regions -Lack of negative feedback from T3 & T4 causes over stimulation and overgrowth of the thyroid gland -Goiter results (enlarged thyroid gland) |
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Parathyroid Glands
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-Four small glands on the posterior surface of the thyroid gland
-Contain principal cells that secrete parathyroid hormone -Parathyroid hormone & calcitonin regulate blood calcium levels |
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How does calcitonin decrease blood calcium?
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-Increasing calcium excretion by the kidneys
-Increasing calcium deposition in the bones |
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How does the parathyroid hormone increase blood calcium?
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-Releasing calcium from bones into blood
-Increasing calcium reabsorption by kidneys -Activating vitamin D that increases calcium absorption from the intestines |
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Suprarenal Glands
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-Adrenal glands
-Located on top of the kidneys -Gross Anatomy: -Enclosed by a fibrous capsule -Outer Cortex -Inner Medulla |
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Zona Glomerulosa
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-Outer zone secreting mineralocoids
-ALDOSTERONE is the major mineralocoid -Increase retention of sodim by kidneys -Increase excretion of potassium by kidneys -Increase water retention and blood volume Aldosterone secretion is regulated by sodium and potassium blood levels |
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Zona Fasciculata
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-Middle zone secreting glucocorticoids
-CORTISOL is the major glucocorticoid -Increase glucose and glycogen synthesis -Increase fatty acids and proteins breaking -Reduce inflammation and allergic rashes Cortisol secretion is regulated by hypothalamic CRH and anterior pituitary ACTH |
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Zona Reticularis
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-Innner zone secreting ANDROGENS
-Stimulate pubic hair growth in puberty -Promote muscle mass, formation of the blood cells and libido in females Androgens regulated by hypothalamic CRH and anterior pituitary ACTH |
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Addison's Disease
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-Insufficient glucocorticoids secretion
-Lack of energy -Weight loss -Loss of sodium and water in urine -Inability to resist stress -John F. Kennedy |
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Cushing's Disease
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-Excessive glucocorticoids secretion
-Muscle wasting -Body fat redistribution -Spindly thin arms and legs -Rounded face (moon face) -Fatty hump between shoulders (buffalo hump) -Large abdomen with stretch marks |
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Suprarenal Medulla
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-Develops from the same nervous tissue as the sympathetic nervous system
-Chromaffin cells receive direct innervations from the sympathetic nervous system -Sympathetic stimulation increases hormone secretion by the adrenal medulla -Adrenal medulla hormones are exactly the same in structure and function as the sympathetic nervous system neurotransmitters. -Their effects mimic those of sympathetic NS -They cause fight-flight behavior |
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Catecholamines
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-Epinephrine and norepinephrine
-(adrenaline and noradrenaline) -Targets all body cells -React quickly to stress by: -Increasing heart rate and strength -Increasing blood flow to skeletal muscles, heart and brain -Increases dilation of airways -Increases fuel for energy -Increases blood pressure |
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The Pineal Gland
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-Located in the roof of the third ventricle of the brain
-Contains neurons, neuroglia and the pinealocytes that secrete melatonin hormone -Melatonin secretion lowest during daytime and highest at night |
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Melatonin Functions
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-Timing of sexual maturity:
Melatonin deficiency causes premature puberty in children -Protection: Against damage by free radicals in the CNS -Circadian Rhythm Setting: Increased melatonin secretion may cause seasonal affective disorder (sad) during winter |
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The Pancreas
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-Five inches long, consists of head, body and tail
-Most cells are exocrine producing digestive enzymes -Endocrine cells in pancreatic islets produce hormones |
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Pancreas (Structure)
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-Exocrinne acinar cells surround a small duct
-Endocrine cells secrete near a capillary -1 to 2 million pancreatic islets of langerhans -Contains 4 types of endocrine cells |
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Pancreatic Islets (alpha cells)
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-20%
-Produces Glucagon |
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Pancreatic Islets (beta cells)
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-70%
-Produces insulin |
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Pancreatic Islets (delta cells)
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-5%
-Produce somatostatin |
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Pancreatic Islets (F - cells)
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-5%
-Produce pancreatic polypeptide (PP - cells) |
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Insulin Actions
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-Decreases blood glucose by:
-Increasing uptake of glucose into cells -Increasing synthesis of glycogen in the liver for storage -Increases protein synthesis in cells -Increases fat synthesis in cells |
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Glucagon Actions
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-Increases blood glucose by:
-Increasing synthesis of glucose from amino acids in liver -Increasing breakdown of liver glycogen into glucose -Increasing the release of glucose from liver into blood Glucagon increases fat breakdown in adipose tissue to free fatty acids (Lypolysis) |
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Regulation of glucagon and insulin secretion
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-High blood glucose after a meal stimulates secretion of insulin and inhibits secretion of glucagon
-Low blood glucose when fasting stimulates release of glucagon and inhibits secretion of insulin |
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Diabetes Mellitus
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-A metabolic disorder that produce high glucose levels in the blood (hyperglycemia)
-Caused by genetic defects that decrease insulin secretion or produce defective insulin molecule or defective insulin receptors -Insulin receptors defects make the cells unable to respond to normal insulin -Carbohydrates, proteins and fat metabolisms are all affected |
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Type I (IDDM) or Juvenile DM
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-Beta cells destroyed by own immune system
-Insulin levels low or absent -Insulin injections required -Usually develops in people younger than 10 |
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Type II (NIDDM) or Maturity onset DM
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-Most common type (90%)
-Insulin may still be secreted but the body cells are less sensitive to insulin actions -Insulin injections may not be required -Mostly in people over 35 who are obese -May be controlled by diet |
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Polyuria
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Excessive urination
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Polydypsia
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Excessive water drinking
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Polyphagia
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Excessive eating
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Intestines
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Intestinal hormones coordinates activities of the digestive system. Most important ones are CHOLECYSTOKININ (CCK), GASTRIN and SECRETION
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Kidneys
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CALCITRIOL is the active form of vitamin D that increases calcium absorption from the intestine
ERYTHRPOIETIN stimulates RBC production RENIN - ANGIOTENSIN - ALDOSTERONE system affect blood volume and blood pressure |
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Heart
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NATRIURETIC PEPTIDE increase sodium and water excretion by the kidneys
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Thymus
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THYMOSINS promote development and maturation of lymphocytes
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Adipose Tissue
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LEPTIN suppress appetite
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Gonads
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TESTOSTERONE and INHIBIN in males
ESTROGENS and PROGESTERONE in females |
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Chromaffin Cells receive direct innvervation from where?
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Sympathetic Nervous System
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Sympathetic stimulation increases the hormone secretion by the what?
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Adrenal Medulla
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Adrenal medulla hormones are the exact same in structure and function as the what?
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Sympathetic nervous system neurotransmitters
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What type of behavior do the medulla hormones cause?
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Fight-Flight
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What type of cells do Human Growth Hormone (hGH) target?
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All, especially skeletal and muscle tissue
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The human growth hormone directly stimulates what?
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-Stem cells division and differentiation
-Stimulates liver synthesis and release of somatomedins |
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Somatomedins INDIRECTLY mediates growth hormone functions by increasing what?
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Protein synthesis and cell division
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What is the result of the human growth hormone (hGH)?
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Growth to adulthood and maintenance of skeleton and muscles in adults
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FSH
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Follicle stimulating hormone
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LH
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Luteinizing Hormone
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(Thyroid Hormones Synthesis)
What do the follicular cells trap? And where is it transported? |
Iodide; follicular lumen
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(Thyroid Hormones Synthesis)
What do the follicular cells synthesize? And where is it transported/ |
Thyroglobulin; follicular lumen
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(Thyroid Hormones Synthesis)
The oxidation of iodide in the lumen makes it turn into what? |
Iodine
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(Thyroid Hormones Synthesis)
What enzyme causes the oxidation of iodide in the lumen? |
Thyroid Peroxidase
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(Thyroid Hormones Synthesis)
What goes through iodination in the thyroglobulin chain to form T1 and T2? |
Tyrosine Molecules
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(Thyroid Hormones Synthesis)
T1 and T2 couple to make what? |
T3 and T4
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(Thyroid Hormones Synthesis)
What do follicular cells do to the thyroglobulin chain to produce free T3 and T4? |
Pinocytosis
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(Thyroid Hormones Synthesis)
What digests the thyroglobulin chain to produce T3 and T4? |
Lysosomal Enzymes
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(Thyroid Hormones Synthesis)
Where is T3 and T4 secreted after the thyroglobulin chain has gone through pinocytosis and digestion? |
Blood
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(Thyroid Hormones Synthesis)
When T3 and T4 is transported in the blood, it stays in the free form or is bound to what? |
Thyroid-binding-globulin
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What do T3 and T4 increase?
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Basal metabolic rate (BMR) of all cells
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The lack of negative feedback from T3 and T4 causes over stimulation and overgrowth of which gland?
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Thyroid
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What type of region does Endemic Goiters mostly occur in?
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Arid, dry, inland
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What causes Endemic Goiter?
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Iodine Deficiency and Insufficient dietary iodine to make T3 and T4
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Where is the location of the parathyroid glands?
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Posterior surface of thyroid gland
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What do Principal cells of the parathyroid secrete?
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Parathyroid Hormone
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What regulates blood calcium levels?
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Parathyroid hormone and calcitonin
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Where are the adrenal glands located?
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On top of the kidneys
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What's the gross anatomy of the adrenal glands?
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-Enclosed by a fibrous capsule
-Outer Cortex -Inner Medulla |
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Which zone is the Zona Glomerulosa located?
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Outer
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(Zona Glomerulosa)
What does the outer zone secrete? |
Mineralocorticoids
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What is the major mineralocorticoid?
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Aldosterone
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How is aldosterone secretion regulated?
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Sodium and potassium blood levels
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What zone is the Zona Fasciculata located?
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Middle
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What is the major glucocorticoid?
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Cortisol
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How is cortisol secretion regulated?
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Hypothalamic CRH and anterior pituitary ACTH
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What zone is the Zona Reticularis located?
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Inner
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What does the inner zone secrete?
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Androgens
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What do Zona Reticularis stimulate?
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Pubic hair growth in puberty
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What do Zona Reticularis promote?
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-Muscle mass
-Formation of blood cells -Libido in females |
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How are androgens regulated?
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Hypothalamic CRH and anterior pituitary ACTH
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Where is the pineal gland located?
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Roof of the third ventricle of the brain
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What does the pineal gland contain?
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-Neurons
-Neuroglia -Pinealocytes that secrete melatonin hormone |
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Melatonin secretion is lowest during when?
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Daytime
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Melatonin secretion is highest during when?
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Night time
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What type of cells in the pancreatic islets produce hormones?
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Endocrine
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Most cells in the pancreas are described as what?
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Exocrine producing digestive enzymes
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What do exocrine acinar cells surround in the pancreas?
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Small duct
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Endocrine cells secrete near what?
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Capillary
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After a meal stimulates secretion of insulin and inhibits secretion of glucagon
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High Blood Glucose
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When fasting stimulates release of glucagon and inhibits secretion of insulin
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Low blood glucose
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Hyperglycemia
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Metabolic disorder that produce high glucose levels in the blood
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What causes Diabetes Mellitus?
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Genetic defects that:
-Decrease insulin secretion -Produce defective insulin molecule -Defective insulin receptors |
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What are affected from diabetes mellitus as far as diet?
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-Carbohydrates
-Proteins -Fat metabolisms |