Endocrine System Flashcards

Question

_Growth Hormone_ * Widespread effects – mitosis in \_\_\_, \_\_\_, & \_\_\_ * Induces ___ to produce growth \_\_\_ – Insulin-like Growth Factors (IGF-I) or somatomedins (IGF-II) • stimulate target cells in \_\_\_\_ • IGF-I prolongs \_\_\_\_\_\_ • hormone half-life—time required for ___ of hormone to be \_\_\_\_ – GH half-life: ____ – IGF-I half-life: ~\_\_\_\_

Answer 1

_Growth Hormone_ * Widespread effects – mitosis in ***CARTILAGE***, ***MUSCLE***, & ***BONE*** * Induces ***LIVER*** to produce growth ***STIMULANTS*** – Insulin-like Growth Factors (IGF-I) or somatomedins (IGF-II) • stimulate target cells in ***DIVERSE TISSUES*** * IGF-I prolongs ***GH ACTION*** * hormone half-life—time required for ***50%*** of hormone to be ***CLEARED FROM BLOOD*** – GH half-life: **6-20MIN** – IGF-I half-life: ~**20HRS**

Answer 2

_Growth Hormone_ * **PROTEIN** synthesis increases: boosts **TRANSCRIPTION** (DNA --\> **mRNA**), **AMINO ACID** uptake into cells, suppresses **PROTEIN** catabolism * **LIPID** metabolism increases: fat catabolism by **ADIPOCYTES** (protein-sparing effect), provides energy for growing **TISSUES** * **CARBOHYDRATE** metabolism: **GLUCOSE**-sparing effect, mobilizes fatty acids, reduces dependence of cells on **GLUCOSE** (allows to save **GLUCOSE** for brain) * **ELECTROLYTE** balance: promotes Na+, K+, & Cl− retention by **KIDNEYS**, enhances Ca2+ absorption in **INTESTINES** * **BONE** growth, **THICKENING**, & **REMODELING** influenced, especially during childhood / adolescence * Secretion high during first 2 hrs of **SLEEP** * Can peak in response to **VIGOROUS EXERCISE** * Levels decline w/ **AGE**

Answer 3

_Pineal Gland_ • above **3RD VENTRICLE**; very central • after age 7, undergoes **INVOLUTION** (shrinkage) – down 75% after **PUBERTY** (tiny mass of **SHRUNKEN TISSUE** in adults) • may synchronize **PHYSIOLOGY** w/ 24-hour **CIRCADIAN** rhythms of daylight / darkness – synthesizes **MELATONIN** from **SERATONIN** at night • fluctuates **SEASONALLY** w/ changes in day length • may regulate timing of **PUBERTY** in humans • **SEASONAL AFFECTIVE DISORDER** (**SAD**) occurs in winter of northern climates – depression, **SLEEPINESS**, irritability, **CARBOHYDRATE** craving – 2-3 hrs of exposure to bright light / day reduces **MELATONIN** levels & symptoms (**PHOTOTHERAPY**)

Answer 4

_Thymus_ * role in three systems: **LYMPHATIC**, **IMMUNE**, **ENDOCRINE** * bi-lobed gland in **MEDIASTINUM**, superior to **HEART** (**INVOLUTION** after puberty) * site of maturation of **T CELLS** - **IMMUNE** defense * secretes hormones (**THYMOSIN**, **THYMULIN**, **THYMOPOIETIN**) that stimulate development of **LYMPHATIC** organs & activate **T-CELLS**

Answer 5

_Thyroid Gland_ • **LARGEST** endocrine gland – **2** lobes + isthmus below **LARYNX** – dark reddish brown color b/c rich **BLOOD** supply • Thyroid follicles— **SACS** – contain **PROTEIN**-rich colloid – follicular cells: simple **CUBOIDAL** epithelium lines **FOLLICLES** • Secretes **THYROXINE** (T4 for 4 **IODINE** atoms) & triiodothyronine (T3) - converted fromT4 (increases **METABOLIC** rate, **O2** consumption, **HEAT** production (calorigenic effect), appetite, **GH** secretion, alertness, **REFLEXES**) • **PARAFOLLICULAR** (C or clear) cells secrete **CALCITONIN** – stimulates **OSTEOBLAST** activity – lowers **BLOOD CALCIUM** level

Answer 6

_Parathyroid Glands_ • **4** glands partially embedded in **POSTERIOR** surface of **THYROID** * Secrete **PARATHYROID** hormone (**PTH**) – **INCREASES** blood Ca2+ levels * promotes synthesis of **CALCITRIOL** * increases **ABSORPTION** of Ca2+ * **DECREASES** urinary excretion * increases **BONE RESORPTION** (opposite of calcitonin - pulling calcium out of blood material and putting it back into blood)

Answer 7

_Adrenal Glands_ * sit on top of each **KIDNEY** * retroperitoneal (like kidney) * adrenal **CORTEX** & **MEDULLA** know picture!!

Answer 8

Know name of zone, what they look like, and what they produce

Answer 9

_Adrenal Medulla_ • **INNER CORE**, 10-20% of gland • Dual nature: **ENDOCRINE** gland & **SYMPATHETIC** ganglion of **SYMPATHETIC NERVOUS** system – innervated by **SYMPATHETHIC PREGANGLIONICIC** fibers – consists of **MODIFIED SYMPATHETIC POSTGANGLIONIC** neurons: **CHROMAFFIN** cells – release **CATECHOLAMINES** (epinephrine & norepinephrine) & trace of **DOPAMINE** directly into **BLOOD** • Effect: longer lasting than **NEUROTRANSMITTERS** – increases **ALERTNESS**, preps body for **PHYSICAL ACTIVITY** • mobilizes high-energy **FUELS**, **LACTATE**, **FATTY ACIDS**, **GLUCOSE** • **GLYCOGENOLYSIS** & **GLUCONEOGENESIS** boost glucose levels • glucose-sparing effect because inhibits **INSULIN SECRETION** – muscles use **FATTY ACIDS**, saving glucose for **BRAIN** – increases **BLOOD PRESSURE**, **HEART RATE**, blood flow to **MUSCLES**, **PULMONARY** airflow, **METABOLIC** rate – decreases **DIGESTION** & **URINE** production Sounds like **FIGHT OR FLIGHT RESPONSE**

Answer 10

_Adrenal Cortex_ * Surrounds **ADRENAL MEDULLA** * Produces \> 25 **STEROID** hormones called **CORTICOSTEROIDS** (or corticoids) * Secretes major steroid hormones from three layers of **GLANDULAR TISSUE** – Zona glomerulosa (**THIN**, **OUTER** layer) • cells in **ROUND CLUSTERS** • secretes **MINERALOCORTICOIDS (EX - ALDOSTERONE - BP REGULATION)** – Zona fasciculata (**THICK**, **MIDDLE** layer) • cells in **FASCICLES** separated by **CAPILLARIES** • secretes **GLUCOCORTICOIDS** (& **SEX** steroids) **(EX - CORTISOL - STRESS HORMONE)** – Zona reticularis (**NARROW**, **INNER** layer) • cells in **BRANCHING** network • secretes **SEX** steroids (& **GLUCOCORTICOIDS**) **(EX - ESTROGEN, PROGESTERON, TESTOSTERONE)**

Answer 11

_Adrenal Cortex_ • Mineralocorticoids—zona **GLOMERULOSA** – regulates **ELECTROLYTE BALANCE** – **ALDOSTERONE** stimulates Na+ retention & K+ **EXCRETION** – water retained w/ Na+ by **OSMOSIS**, so blood **VOLUME** & blood **PRESSURE** maintained Glucocorticoids—zona **FASCICULATA** - regulate **METABOLISM** of glucose & other fuels - cortisol - stimulates **FAT** & **PROTEIN** catabolism, **GLUCONEOGENESIS** (glucose from **AMINO** acids & **FATTY** acids), release of **FATTY** acids & **GLUCOSE** into blood - response to **ACTH** - helps body adapt to **STRESS** & repair **TISSUES** - anti-inflammatory effect becomes **IMMUNE SUPPRESSION** w/ long-term use Sex steroids—zona **RETICULARIS** – androgens: sets **LIBIDO**; imp. role in **PRENATAL** male development (includes DHEA which converts to **TESTOSTERONE**) – estradiol: **SMALL** quantity, but important after **MENOPAUSE** for sustaining **BONE MASS**; fat converts **ANDROGENS** into **ESTROGEN**

Answer 12

_Pancreatic Islets (what produces hormones)_ * exocrine **DIGESTIVE** gland & endocrine **CELL CLUSTERS** (pancreatic islets) * retroperitoneal, inferior/posterior to **STOMACH**

Answer 13

_Pancreatic Islets_ • **GLUCAGON**—secreted by A or alpha ( a) cells (goal is to make glucose and get it into blood) – released betw/ **MEALS** when **BLOOD** glucose concentration is **FALLING** – in **LIVER**, stimulates gluconeogenesis, glycogenolysis; release of **GLUCOSE** into circulation - **RAISES** blood glucose level – in **ADIPSOE** tissue, stimulates **FAT** catabolism, release of **FREE FATTY** acids – promotes **AMINO** acid absorption, & provides cells w/ raw material for **GLUCONEOGENESIS** • **INSULIN** secreted by B or beta (b) cells (gets glucose out of blood and into cells to use for fuel) – secreted **DURING** / **AFTER** meal when glucose & **AMINO** acid blood levels are **RISING** – stimulates cells to **ABSORB** these nutrients & **STORE** or **METABOLIZE** them; lowers **BLOOD** glucose levels • promotes synthesis glycogen, **FAT**, & **PROTEIN** • **SUPPRESSES** use of already-stored fuels • brain, liver, kidneys, & RBCs absorb glucose **WITHOUT** insulin, but other **TISSUES** require insulin – insufficiency / inaction = **DIABETES MELLITUS** • **SOMATOSTATIN** secreted by D or delta ( d) cells – partially **SUPPRESSES** secretion of glucagon & insulin – prolongs **ABSORPTION** of nutrients • **GASTRIN** secreted by G cells – stimulates **STOMACH** acid secretion, **MOTILITY**, & emptying

Answer 14

_Pancreatic Islets_ • **HYPERGLYCEMIC** hormones raise blood glucose concentration – **GLUCAGON**, growth hormone, epinephrine, norepinephrine, **CORTISOL** & corticosterone • **HYPOGLYCEMIC** hormones lower blood glucose – **INSULIN**

Answer 15

_Gonads_ • Ovaries & testes - both **ENDOCRINE** & **EXOCRINE** – exocrine product: **WHOLE CELLS** —eggs & sperm (**CYTOGENIC** glands) – endocrine product: **GONADAL** hormones—mostly **STEROIDS** • Ovarian hormones – estradiol, **PROGESTERONE**, & **INHIBIN** • Testicular hormones – testosterone, weaker **ANDROGENS**, estrogen, & **INHIBIN**

Answer 16

_Hormone Chemistry_ 3 chemical classes: 1. **STEROIDS** • from **CHOLESTEROL** * secreted by **GONADS** & **ADRENAL** glands * **ESTROGEN**, progesterone, **TESTOSTERONE**, cortisol, corticosterone, aldosterone, DHEA, & **CALCITRIOL** 2. **PEPTIDES** & **GLYCOPROTEINS** * from chains of **AMINO** acids * secreted by **PITUITARY** & **HYPOTHALAMUS** • **OXYTOCIN**, ADH, & **ANTERIOR** pituitary hormones 3. **MONOAMINES** (biogenic amines) • from **AMINO** acids • secreted by **ADRENAL**, **PINEAL**, & **THYROID** glands • **EPINEPHRINE**, norepinephrine, melatonin, & **THYROID** hormone All hormones made from either **CHOLESTEROL** or **AMINO** acids w/ carbohydrate added to make **GLYCOPROTEINS**

Answer 17

_Hormone Transport_ • Most monoamines & peptides = **HYDROPHILLIC** (mix **EASILY** w/ blood) • Steroids & thyroid hormone = **HYDROPHOBIC** – bind to **TRANSPORT PROTEINS** (albumins & globulins from **LIVER**) – **BOUND** hormones have longer half-life – only **UNBOUND** hormone leaves capillaries to reach **TARGET** cell – transport proteins **PROTECT** circulating hormones from: degradation by **ENZYMES** in **PLASMA** & liver - filtration out of blood by **KIDNEYS** • **THYROID** hormone binds to 3 transport proteins in plasma – **ALBUMIN**, **THYRETIN**, **THYROXINE-BINDING GLOBULIN** (**TBG**) – \> 99% of circulating TH = **PROTEIN** bound • Steroid hormones bind to **GLOBULINA** – Ex. Transcortin = **TRANSPORT** protein for cortisol • **ALDOSTERONE**—short half-life; 85% unbound, 15% binds **WEAKLY** to **ALBUMIN** (& others)

Answer 18

_Hormone Receptors & Mode of Action_ • Hormones only stimulate cells w/ **RECEPTORS** for them * **TARGET CELL** has ~1000s receptors for given hormone * Receptor–hormone interactions exhibit **SPECIFICITY** & **SATURATION** – specific **RECEPTOR** for each hormone – **SATURATED** when all **RECEPTOR** molecules occupied by **HORMONES** molecules • Receptors = **PROTEINS**/ **GLYCOPROTEIN** molecules – on **PLASMA** membrane, in cytoplasm, or in **NUCLEUS** – act like switches, turn on **METABOLIC** pathways when hormone **BINDS**

Answer 19

_Hormone Receptors & Mode of Action_ • Hydrophilic hormones – need **MEMBRANE RECEPTOR** – changes physiology thru **SECOND MESSENGER** • Hydrophobic hormones – through **PLASMA MEMBRANE**, enter **NUCLEUS** – act directly on **GENES** changing target cell **PHYSIOLOGY** – **ESTROGEN**, progesterone, **THYROID** hormone act on **NUCLEAR** receptors – take several **HOURS TO DAYS** to show effect (lag time for **PROTEIN SYNTHESIS**)

Answer 20

_Steroids & Thyroid Hormone_ * Thyroid hormones enters **TARGET CELL** by **DIFFUSION**, mostly as **T4** (little metabolic effect) * Within **TARGET CELL**, **T4** converted to more potent **T3** * **T3** enters **TARGET CELLS**, binds to receptors in **CHROMATIN** * activates **GENES** (makes **MYOSIN**, enhancing **CARDIAC** muscle response and strengthening **HEARTBEAT**)

Answer 21

_Peptides & Catecholamines_ * hormone binds to **CELL-SURFACE** receptor * receptor linked to **SECOND MESSENGER SYSTEM** * most common: * activates **G** protein --\> activates **ADENYLATE CYCLASE** --\> produces **cAMP** * activates / inhibits **ENZYMES** * **METABOLIC** effects

Answer 22

_Enzyme Amplification (one little hormone can do a lot)_ * hormones = extraordinarily **POTENT** chemicals! * one **HORMONE** molecule --\> synthesis of many **ENZYME** molecules * **SMALL** stimulus --\> **LARGE** effect * circulating concentrations very **LOW**

Answer 23

_Hormone Interactions (know names of effects and examples that go with them)_ Most cells sensitive to \> one **HORMONE** Synergistic effects - **MULTIPLE** hormones act together for greater effect (Ex - **FSH** & **TESTOSTERONE** on sperm production) Permissive effects one hormone enhances target organ’s response to **SECOND LATER HORMONE** Ex - **ESTROGEN** preps uterus for **PROGESTERONE** (hormones paves the way) Antagonistic effects one hormone **OPPOSES** action of another ex) insulin and **GLUCAGON**

Answer 24

_Hormone Clearance_ • Turning **OFF** hormone signals when they have served purpose • Metabolic clearance rate (MCR) – rate of hormone **REMOVAL** from blood – half-life: time required to clear 50% of hormone from **BLOOD**

Answer 25

_Stress & Adaptation_ • Stress—when **HOMEOSTASIS** upset; threatens **PHYSICAL** or **EMOTIONAL** well-being – injury, **SURGERY**, infection, intense exercise, **PAIN**, grief, **DEPRESSION**, anger, etc. • General Adaptation Syndrome – consistent way body reacts to **STRESS**; involves elevated levels of **EPINEPHRINE** & **GLUCOCORTICOIDS** (especially **CORTISOL**) – occurs in 3 stages: alarm reaction, resistance, and exhaustion

Answer 26

_Anti-Inflammatory Drugs_ • Cortisol & corticosterone – **STEROIDAL ANTI-INFLAMMATORY DRUGS** (SAIDs) – inhibit **INFLAMMATION** by blocking **RELEASE** of arachidonic acid & inhibiting eicosanoid synthesis • disadvantage—**CUSHING** syndrome symptoms • Aspirin, ibuprofen, & naproxen (Aleve) – **NONSTEROIDAL ANTI-INFLAMMATORY DRUGS** (NSAIDs) • **COX INHIBITORS**: block cyclooxygenase • useful in treatment of **FEVER** & **THROMBOSIS**

Answer 27

_Endocrine Disorders_ • Hyposecretion—inadequate **HORMONE** release (gland **DESTROYED** or lost ability to receive **SIGNALS** from another gland) Ex. – **PITUITARY'S** inability to secrete ADH --\> Diabetes insipidus: chronic **POLYURIA** from lack of ADH – Addison’s disease – deficiency of **GLUCOCORTICOIDS** & **MINERALOCORTICOIDS** – hypothyroidism * Hypersecretion—excessive **HORMONE** release (**TUMORS** or **AUTOIMMUNE** disorder) * Toxic goiter (Graves disease)— **AUTO****ANTIBODIES**mimic effect of**TSH**on thyroid, causing thyroid**HYPERSECRETION** * endemic goiter – lack of **IODINE**, no **TH**; **TSH** in overdrive, hypertrophy of thyroid

Answer 28

_Endocrine disorders_ * Pheochromocytoma—tumor of **ADRENAL MEDULLA** secretes excessive **EPINEPHRINE** & norepinephrine * Cushing syndrome – excess of **CORTISOL**

Answer 29

_Diabetes Mellitus_ • Most prevalent metabolic disease – disruption of metabolism due to **HYPOSECRETION** or inaction of **INSULIN** – symptoms: • poly**URIA**, poly**DIPSIA** & poly**PHAGIA** • revealed by elevated **BLOOD** **GLUCOSE**; **GLUCOSE** & **KETONES** in urine • Transport maximum—limit to how fast **GLUCOSE** transporters can **REABSORB** – excess glucose enters **URINE** & **WATER** follows it! • dehydration

Answer 30

_Types of Diabetes Mellitus & Treatment_ • Type 1 (IDDM)—5-10% of US cases – problem: insulin **INSUFFICIENCY** **INSULIN** used to treat • injections, pump, or dry inhaler • monitoring **BLOOD GLUCOSE** levels & controlling **DIET** – hereditary susceptibility if infected w/ certain viruses (rubella, cytomegalovirus) – **AUTOANTIBODIES** attack & destroy pancreatic **BETA** cells • Type 2 (NIDDM)—90-95% of diabetics – problem: insulin **RESISTANCE** • failed response of **TARGET CELLS** to insulin – risk factors: heredity, age (40+), **OBESITY**, **ETHNICITY** – treated w/ weight-loss program & exercise since: • loss of **MUSCLE MASS** causes difficulty w/ regulation of **GLYCEMIA** • **ADIPOSE** signals interfere w/ glucose uptake into most cells – oral medications improve insulin **SECRETION** or target cell **SENSITIVITY**

Answer 31

_Pathogenesis_ • Cells cannot absorb **GLUCOSE**; rely on **FAT** & **PROTEIN** for energy, thus weight loss & **WEAKNESS** – fat catabolism increases **FREE FATTY ACIDS** & **KETONES** in blood * Ketonuria promotes **OSMOTIC DIURESIS**, loss of Na+ & K+, irregular **HEARTBEAT**, & **NEUROLOGICAL** issues * Ketoacidosis - ketones decrease **BLOOD pH** (diabetic coma)

Answer 32

_Pathogenesis_ • Chronic pathology (chronic hyperglycemia) – **NEUROPATHY** & **CARDIOVASCULAR** damage * Diabetic neuropathy— **NERVE** damage from poor blood flow can lead to erectile disfunction, **INCONTINENCE**, poor **WOUND** healing, loss of **SENSATION** * arterial damage in **RETINA** & **KIDNEYS** (common in type 1) * atherosclerosis leads to **HEART FAILURE** (common in type 2)

Endocrine System Flashcards

(59 cards)