Download - ENDOCRINE SYSTEM Review
ENDOCRINE SYSTEMReview
PETER REONISTO, MDMOORPARK 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.
Endocrine cells of the body contained in:
1. “Pure” endocrine organs
Pituitary gland
Pineal gland
Thyroid gland
Parathyroid gland
Adrenal gland
Major Endocrine Organs
Major Endocrine Organs
Endocrine cells of the body contained in:
2. “Partly” endocrine organs
Pancreas
Thymus
Gonads
Hypothalamus
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 SECRETION1. Humoral2. Neural3. Hormonal
CONTROL OF HORMONE SECRETION1. Humoral- influenced by plasma concentration of the substance.Parathyroid
gland
Low Ca2+ blood concentration
Parathyroid gland
Parathormone secretion
Nephron, intestinal cells
Action
CONTROL OF HORMONE SECRETION2. Neural- SNS stimulationAdrenal medulla
Preganglionic SNSfibers
Medulla of adrenal gland
Body
Actions: “Fight, flight, or fright” response
Adrenaline secretion
CONTROL OF HORMONE SECRETION3. Hormonal-influenced by the amount of hormones in the plasma
Releasinghormones Hypothalamus
Adenohypohysis
Thyroidgland
Body
Releasing hormones
Stimulating Hormones
Adrenalcortex
Gonads(Testis)
Cortisol Androgens
Thyroxine Cortisol Androgens
IncreaseMetabolic
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 theSella turcica of the
Spenoid bone
ANATOMY: PITUITARY GLAND
infundibulum
Anterior Pituitary Gland
Adenohypophysis
1. Pars distalis2. Pars intermedia3. Pars tuberalis
Adenohypophysis
1. 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
Leutenizing Hormone (LH)Gonads: maturation of sex cells; secretes sex hormones
Gonadotropins
Pars distalis 5 CELL CLASSES: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
Leutenizing Hormone (LH)Gonads: maturation of sex cells; secretes sex hormones
F L A T
Tropic Hormones -Regulate the secretionof hormones by other Endocrine glands
M P G
Act directly on non-endocrinetarget tissues
HYPOTHALAMIC CONTROL OF THE ADENOHYPOPHYSIS
Controlled by RELEASING HORMONES and INHIBITING HORMONES
Target cell Target cell PeripheralEndocrine
gland
PeripheralEndocrine
gland
PeripheralEndocrine
gland
-
HYPOPHYSEAL PORTAL SYSTEM
Releasing hormones are made inHypothalamic neurons
Hypothalamic neurons
Releasing hormones are secreted atthe neuron synapse
To the primary capillary complex
Primary capillary complex
Releasing hormones goes to the Hypophyseal portal vein
To the secondary capillary complex
SecondaryCapillarycomplex
Releasing hormones leaves the plexus &attach to the adenohypophyseal cells
SomatotropicMammotropicThyrotropicCorticotropicGonatotropic
Posterior Pituitary Gland
Neurohypophysis1. Median eminence2. Infundibular stalk3. Pars nervosa
Medianeminence
Infundibularstalk
Parsnervosa
NEUROHYPOPHYSIS HORMONE PRODUCTIONHormone produced at neuron cell bodies located at the SUPRAOPTICand PARAVENTRICULAR nuclei ofthe Hypothalamus
Hormones are transportedalong the axons(Hypothalamic-hypophysealTract)
Hormones are stored indilated axon terminalscalled HERRING BODIES
Upon stimulation, stored hormones are released in thecapillary bed for distributionthroughout the body
ADHOxytocin
NEUROHYPOPHYSIS: Hormones
CELL TYPE HORMONE TARGET/EFFECTS
Neurons from supraoptic nucleus of hypothalamus
Antidiuretic hormone (ADH, vasopressin)
Stimulates kidneys (distal tubules and collecting tubules) to reclaim water from urine. Raises blood pressure by constricting peripheral arterioles when blood volume is low.
Neurons from paraventricular nucleus of hypothalamus
Oxytocin Initiates labor through uterine contraction Facilitates milk ejection from breast
MAJOR ENDOCRINE ORGAN
THYROID GLAND
THYROID GLAND located in theanterior neck; on the trachea justinferior to the larynx
PARATHYROID GLANDLocated at the posteriorsurface of the thyroid gland
PARATHORMONE
FUNCTION:Increase bloodCalcium level
ADRENAL GLANDADRENAL CORTEXADRENAL MEDULLA
Mineralocorticoid (Aldosterone)
Glucocorticoid (Cortisol)
Balance electrolyte Concentration (Na+/K+)--Inc Na+ Reabsorption--Inc K+ excretion--Inc water reabsorption
Glucocorticoid (Cortisol)
Produce sex hormone precursor (DHEA) ----Dehydroepiandrosterone---
Stress control
ADRENAL MEDULLA: HormonesSimulate a “fight, fright, flight response”
PANCREAS
Other Endocrine GlandsPineal 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
END