ENDOCRINE SYSTEM Endocrine glands secrete chemical messages into
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ENDOCRINE SYSTEM Endocrine glands secrete chemical messages into the blood stream that affects distant specific target tissues Endocrine Glands are small in size (less than 1/10 th and kg total) but big in maintaining homeostasis. l HORMONES- chemical messengers released into the blood stream that direct activities in the body’s cells l FUNCTIONS l l l Reproduction Growth and development Body defense system Maintain electrolyte, water, and nutrient balance Regulate cellular metabolism
3 CLASSES OF HORMONES 1. Amino acid based- proteins, peptides, and amines 2. Steroids- built around a core of cholesterol (hydrophobic – does not dissolve in water)-sex hormones and adrenal hormones 3. Prostaglandins – fatty acid based- act locally at site of release
How do hormones work? TARGET CELLS or TARGET ORGANS- hormones must attach to specific protein receptors (on the plasma membrane) When hormone binds it typically changes the cell in one of the following ways 1. Changes plasma membrane permeability or electrical state 2. Synthesis of proteins or enzymes in the cell 3. Activate or deactivate enzymes in the cell 4. Stimulation of mitosis (cell division)
STEROIDS- hydrophobic- so therefore fat soluble l l l l Page 281 STEP 1 diffuses through plasma membrane STEP 2 enters the nucleus STEP 3 binds to specific receptor proteins in nucleus STEP 4 binds to specific sites of DNA STEP 5 activates genes STEP 6 genes make new proteins
NONSTEROIDAL HORMONES- not fat soluble l l l Page 281 STEP 1 binds to receptor on plasma memb STEP 2 sets off a series of reactions that activate enzyme STEP 3 - produces a second messenger molecule STEP 4 - produces cells predicted reaction to the hormone
Types of endocrine glands l HORMONAL- glands prodded into action due to hormones l NEURAL- glands prodded into action due to neural stimulation l HUMORAL- changing blood levels of certain ions (Ca+) for example prods the glands into action
NEGATIVE FEEDBACK SYSTEM • Negative feedback limits amount of hormone that is released Hypothalamus Set point Levels OK ? Blood • Yes? • No? Hypothalamus releases a "Releasing Hormone" Pituitary gland releases "Tropic hormone" Peripheral gland releases its hormone
Structure and function of Endocrine glands PITUITARY GLAND (HYPOPHYSIS)- “Master endocrine gland”- located in the sella turcica of the skull consists of 2 functional areas ANTERIOR PITUITARY- secretes the 4 tropic hormones- activates other endocrine glands POSTERIOR PITUITARY- serves as a storage area for two hormones to be used when activated by the neurons of the hypothalamus
ANTERIOR PITUITARY Secretes 4 tropic hormones Receives hormones from hypothalamus called “regulating factors” 1. Growth hormone (GH) l l TROPIC HORMONES 1. Thyroid stimulating hormone (TSH) 2. Adrenocorticotropic hormone (ACTH) 3. Gonadotropins 1. 2. Follicle stimulating hormone (FSH) Luteinizing hormone (LH)
GROWTH HORMONE (increases amino acid transport into cells and increases protein synthesis, synthesis mitosis, and cartilaginous bone growth) l Growth hormone acts on liver and bone (growth plates) l Overproduction of (GH) will result in gigantism. Or if occurs after long bone formation has completed Acromegaly will occur l Underproduction of (GH) will result in pituitary dwarfism l
Growth Hormone
Thyroid stimulating hormone l Controls production of metabolic regulatory hormones from thyroid gland
Adrenocorticotropic hormone l Controls adrenal cortex production of corticosteroid hormones
Follicle Stimulating Hormone l females – FSH promotes synthesis of estrogen and development and growth of follicles in ovaries to become oocyte(s) l males – FSH promotes production of sperm in testes
Luteinizing Hormone l 1) females – promotes sex hormone production and release of oocyte from follicle l 2) males – promotes sex hormone production
Posterior lobe of pituitary l Anti-Diuretic Hormone (ADH) -VASOPRESSIN- causes collecting ducts of nephron to re-absorb more water from urine. Underproduction leads to diabetes insipidus (dehydration) Causes contraction of uterine smooth muscle (i. e. LABOR!!!) Release (post-partum) causes contraction of milk ducts in mammary l Oxytocin-
Intermediate pituitary l MELANOCYTE STIMULATING HORMONEtargets the melanocytes in skin, hair, and eyes to make more melanin. More active in pregnant women. (common in animals which change fur color) Controlled by regulating hormones in hypothalamus Underproduction leads you susceptible to sunburns
Pineal gland l Produce all cells. l Effects- the hormone melatonin- targets circadian rhythms, protect vs free radicals, inhibits reproductive functions
THYROID GLAND Located ate the base of the throat just inferior to the Adam’s apple l Two large lobes joined by an isthmus l Produces- Thyroxine and Calcitonin Thyroxine- stimulates metabolismcontains iodine l People with not enough iodine in their diet get GOITERS. Negative feedback loop tells thyroid to keep producing but lack of iodine makes the molecule nonfunctional
Thyroid Goiter
Thyroid Gland l Hypothyroidism- Cretinism- “dwarfism” occurs in early childhood l In adults results in MYXEDEMA- physical or mental sluggishness
Thyroid Gland l Hyperthyroidism- high metabolic rate, intolerance of heat, rapid heartbeat, nervous behavior l GRAVE’s DISEASEthyroid enlarges and eyes bulge
Thyroid gland l CALCITONIN- decreases blood calcium levels by causing calcium to be deposited into bones l Hyposecretion- elderly adults lead to decalcification in
PARATHYROID GLAND l PARATHYROID HORMONE- regulates calcium level in blood- when low it decalcifies bone to add to blood supply - If blood calcium levels fall too low then neurons become irritable and overactive. -Hyperparathyroidism- causes massive bone destruction-
THYMUS l THYMOSIN- lymphocytes l Thymus programs certain stores “T cells” until they mature
Adrenal Cortex l Mineralcorticoids- regulate salt and potassium in the blood ALDOSTERONE- high levels in the blood reclaim sodium and allow potassium out in urine l When sodium is absorbed then water will flow smoother l Hyposecretion- ADDISON’S DISEASE- sodium and water are lost from the body- skin appears bronze and muscles become weak l Hypersecretion- excessive water and sodium retainedpotassium severely lostl
RENIN l Enzyme produced by the kidneys that controls the release of ALDOSTERONE
Adrenal Cortex l CORTISONE- promote normal cell metabolism- resists long-term stressorsl l Have antiinflammatory and pain inhibitors Hypersecretion. CUSHING’S SYNDROME- “buffalo hump”
Adrenal Cortex l ANDROGENS- male sex hormones hypersecretion- masculinization regardless of sex -ESTROGEN- female sex hormonesproduction of female characteristics
ADRENAL MEDULLA l EPINEPHRINE (ADRENALINE) AND NOREPINEPHRINEProlongs the effects of the sympathetic nervous system Hyposecretion- no major effects
PANCREAS l INSULIN- acts on all body cells and increases their ability to take glucose in through cell membrane l Takes glucose out of blood l Without insulin- glucose will be lost out urine along with excess water- dehydration. DIABETES MELLITUS l Too much insulin- leads to hypoglycemia
PANCREAS l 3 COMMON SIGNS OF DIABETES l 1. l 2. l 3. sugars excessive urination excessive thirst hunger due to inability to take in
PANCREAS l GLUCAGON- adds glucose to bloodstimulates liver to breakdown glycogen into glucose l Hyposecretion / hypersecretion- no important disorders
l Somatostatin- GH-IH- targets other cells in the pancreas inhibits insulin and PANCREAS glucagon secretionl Stimulated by protein-rich meal l Pancreatic polypeptide- targets gall bladder- regulates gall bladder contraction l Stimulated by protein-rich meal
OVARIES l ESTROGENS- stimulate secondary sex characteristics in women- l ESTROGEN AND PROGESTERONE- prepares the uterus to receive a fertilized egg- Menstrual Cycle Prepares breasts for milk production l Helps maintain pregnancy l HYPOSECRETION- inhibits woman’s fertility menopause Hypersecretion- increased breast cancer and ovarian cancer l
TESTES l ANDROGENS- male sex hormones l TESTOSTERONE- characteristics l Production causes male sex of sperm l Hyposecretion- sterility
PLACENTA l HUMAN CHORIONIC GONADOTROPINstimulates the production of more estrogen and progesterone l Home pregnancy tests test for Human chorionic gonadotropin
PINEAL GLAND l MELATONIN- “sleep trigger” establishes the day/night cycle l Coordinates hormones of fertility
KIDNEYS l ERYTHROPOIETIN- targets the red bone marrow to make more red blood cells- l Overproduction- too many RBC which will l Underproduction- too few RBC- which thicken the blood leads to ANEMIA
- What are chemical signals
- Glands secrete what in reflex actions
- Endocrine glands
- Holocrine
- Major endocrine glands male and female
- Endocrine system organs
- Difference between endocrine and exocrine glands
- Are endocrine glands ductless
- Adrenal cushing
- Whats the difference between endocrine and exocrine glands
- Chapter 11 endocrine system
- Endocrine glands
- Endocrine glands
- Hyophysis
- Endocrine glands of rat
- Gastric secretion composition
- Gastric secretions
- Circumcised
- Type 2 pneumocytes secrete
- Type 2 pneumocytes secrete
- Type 2 pneumocytes secrete
- Type 2 pneumocytes surfactant
- Gastric secretion phases
- The suprarenal (adrenal) medullae secrete
- Steroid function
- The suprarenal medullae secrete
- Endocrine system and reproductive system
- Endocrine system vs nervous system
- Lympathic
- Endocrine vs nervous system venn diagram
- Endocrine system
- Glands in integumentary system
- Adenohypophysis
- Sympathetic nervous system
- Comparison of endocrine and nervous system
- Gonads glands
- Facts about the endocrine system
- Tropic hormones hypothalamus
- Metabolic action of growth hormone
- Chapter 7 13 endocrine system