330 likes | 538 Views
ENDOCRINE SYSTEM Review. PETER REONISTO, MD MOORPARK COLLEGE. Nervous System vs. Endocrine System. 3) Hormones travel more slowly than nerve impulses, the endocrine system tends to regulate slow processes such as growth and metabolism. Major Endocrine Organs. Pineal gland.
E N D
ENDOCRINE SYSTEMReview PETER REONISTO, MD MOORPARK COLLEGE
Nervous System vs. Endocrine System 3) Hormones travel more slowly than nerve impulses, the endocrine system tends to regulate slow processes such as growth and metabolism.
Major Endocrine Organs Pineal gland Pituitary gland Thyroid gland Parathyroid gland Endocrine cells of the body contained in: Adrenal gland 1. “Pure” endocrine organs
Major Endocrine Organs Hypothalamus Endocrine cells of the body contained in: Thymus Pancreas 2. “Partly” endocrine organs Gonads
CLASSES OF HORMONES AMINO ACID-BASED • Most hormones • Proteins • Modified amino acid peptides STEROIDS • Lipid molecules derived from cholesterol • Sex hormones • Adrenal cortex hormones
CONTROL OF HORMONE SECRETION • Humoral • Neural • Hormonal
CONTROL OF HORMONE SECRETION • Humoral- influenced by plasma concentration of the substance. Low Ca2+ blood concentration Parathyroid gland Parathyroid gland Parathormone secretion Nephron, intestinal cells Action
CONTROL OF HORMONE SECRETION Preganglionic SNS fibers Adrenal medulla 2. Neural- SNS stimulation Medulla of adrenal gland Adrenaline secretion Body Actions: “Fight, flight, or fright” response
CONTROL OF HORMONE SECRETION Releasing hormones 3. Hormonal-influenced by the amount of hormones in the plasma Hypothalamus Releasing hormones Adenohypohysis Stimulating Hormones Thyroid gland Adrenal cortex Gonads (Testis) Thyroxine Cortisol Androgens Body Cortisol Androgens Increase Metabolic rate Anti-stress Sperm formation
MAJOR ENDOCRINE ORGAN PITUITARY GLAND
PITUITARY GLAND • Or, hypohysis • Secretes at least 9 major hormones • Location: > Hypophyseal fossa Depression in the Sella turcica of the Spenoid bone
ANATOMY: PITUITARY GLAND infundibulum
Adenohypophysis • Pars distalis • Pars intermedia • Pars tuberalis
Adenohypophysis • Pars distalis • Largest division • Contains 5 different endocrine cells that make and secrete 7 different hormones
Pars distalis 5 CELL CLASSES: 1. Somatotrophic cell (most abundant) 2. Mammotrophic cells 3. Thyrotrophic cells 4. Corticotrophic cells 5. Gonadotrophic cells Growth Hormone (Somatotrophic Hormone / Somatotropin / GH) Growth of the entire body Prolactin (PRL) Breast milk production Thyroid Stimulating Hormone (TSH) Thyroid gland stimulation to release thyroid hormone Adrenocorticotropic Hormone (ACTH) Adrenal Cortex stimulation to release glucocorticoids Melanocyte Stimulating Hormone (MSH) Stimulates melanocytes to produce melanin pigment Follicle Stimulating Hormone (FSH) Gonads: maturation of sex cells; secretes sex hormones Gonadotropins Leutenizing Hormone (LH) Gonads: maturation of sex cells; secretes sex hormones
Pars distalis 5 CELL CLASSES: Growth Hormone (Somatotrophic Hormone / Somatotropin / GH) Growth of the entire body Act directly on non-endocrine target tissues Prolactin (PRL) Breast milk production M P G Thyroid Stimulating Hormone (TSH) Thyroid gland stimulation to release thyroid hormone Tropic Hormones - Regulate the secretion of hormones by other Endocrine glands Adrenocorticotropic Hormone (ACTH) Adrenal Cortex stimulation to release glucocorticoids F L A T Melanocyte Stimulating Hormone (MSH) Stimulates melanocytes to produce melanin pigment Follicle Stimulating Hormone (FSH) Gonads: maturation of sex cells; secretes sex hormones Leutenizing Hormone (LH) Gonads: maturation of sex cells; secretes sex hormones
HYPOTHALAMIC CONTROL OF THE ADENOHYPOPHYSIS Controlled by RELEASING HORMONES and INHIBITING HORMONES - Peripheral Endocrine gland Peripheral Endocrine gland Peripheral Endocrine gland Target cell Target cell
HYPOPHYSEAL PORTAL SYSTEM Hypothalamic neurons Releasing hormones are made in Hypothalamic neurons Primary capillary complex Releasing hormones are secreted at the neuron synapse To the primary capillary complex Releasing hormones goes to the Hypophyseal portal vein To the secondary capillary complex Secondary Capillary complex Releasing hormones leaves the plexus & attach to the adenohypophyseal cells Somatotropic Mammotropic Thyrotropic Corticotropic Gonatotropic
Neurohypophysis 1. Median eminence 2. Infundibular stalk 3. Pars nervosa Median eminence Infundibular stalk Pars nervosa
NEUROHYPOPHYSIS HORMONE PRODUCTION Hormone produced at neuron cell bodies located at the SUPRAOPTIC and PARAVENTRICULAR nuclei of the Hypothalamus Hormones are transported along the axons (Hypothalamic-hypophyseal Tract) Upon stimulation, stored hormones are released in the capillary bed for distribution throughout the body Hormones are stored in dilated axon terminals called HERRING BODIES ADH Oxytocin
MAJOR ENDOCRINE ORGAN THYROID GLAND
THYROID GLAND located in the anterior neck; on the trachea just inferior to the larynx
PARATHYROID GLAND Located at the posterior surface of the thyroid gland
PARATHORMONE FUNCTION: Increase blood Calcium level
ADRENAL GLAND ADRENAL CORTEX ADRENAL MEDULLA Balance electrolyte Concentration (Na+/K+) --Inc Na+ Reabsorption --Inc K+ excretion --Inc water reabsorption Mineralocorticoid (Aldosterone) Glucocorticoid (Cortisol) Stress control Glucocorticoid (Cortisol) Produce sex hormone precursor (DHEA) ----Dehydroepiandrosterone---
ADRENAL MEDULLA: Hormones Simulate a “fight, fright, flight response”
Other Endocrine Glands • Pineal Gland • secretes melatonin • regulates circadian rhythms • Thymus Gland • secretes thymosins • promotes development of certain lymphocytes • important in role of immunity • Reproductive • ovaries produce estrogens and progesterone • testes produce testosterone • placenta produces estrogens, progesterone, and gonadotropins