Biology of Man 511 



Summary of Endocrine (Ductless) Glands — Cont'd 



ENDOCRINE 

 GLAND 



HORMONES AND FUNCTIONS 



THYROID 



(thi'-roid) (Gr. 

 thyreos, shield; 

 eidos, resemble) 



. PARATHY- 

 ROIDS 



(para -thi' roid) 

 (Gr. para, beside; 

 thyroid) 



ADRENALS 



(ad -re' nal) (L. 

 ad, to; renes, kid- 

 ney) 

 SUPRARENALS 



5. PANCREAS 



(pan' kreas) 

 (Gr. pan, all; 

 kreas, flesh) 



Thyroxin (thyroglobulin) — Controls rate of basal metab- 

 olism and normal body growth 

 A. HYPERTHYROIDISM (OVERACTIVITY OF 

 NORMAL-SIZED GLAND OR INCREASED 

 GLAND) 

 1. Exophthabnic Goiter — thyroid may be enlarged with 

 such symptoms as increased heartbeat, nervousness and 

 restlessness, often protruding eyeballs, increased heat 

 production and perspiration, increased blood pressure, 

 muscular weakness, and tremors 

 B. HYPOTHYROIDISM (UNDERACTIVITY) 



1. Simple goiter — thyroid may be enlarged (not always) 

 and thyroxin deficient because of lack of iodine; symp- 

 toms may resemble somewhat those of mild myxedema 



2. Myxedema — Deficiency of thyroxin in adult may result 

 in lowered metabolism and heat production, slow pulse, 

 physical and mental lethargy; appetite usually normal 

 with tendency to obesity; dry, waxy, puffy skin because 

 of increased mucus beneath it; dry hair usually falls 

 out. 



3. Cretinism — Insufficient hormone during early life may 

 result in improper development, physically, mentally, 

 and sexually. 



1. Parathormone (parathyrin) — regulates calcium and 

 phosphorus metabolism; proper amount necessary for 

 normal bone development; too little parathormone 

 lowers blood calcium and increases irritability of nerves 

 and muscles; too much withdraws calcium from bones 

 (soft bones) ; complete removal of parathyroids results 

 in tetany or quick death (tremors and convulsions due 

 to increased irritability of muscles and nerves because 

 of lack of calcium) 



CORTEX (OUTER LAYER) 



1. Cortin (probably several hormones? ) — Influences 

 growth excretion, sugar metabolism, water balance, 

 sodium, potassium, and chloride balance, normal sexual 

 functioning; cortin deficiency in man may cause Addi- 

 son's disease (bronzed skin, decreased heart action and 

 blood pressure, muscular weakness, digestive upsets) 

 MEDULLA (INNER PORTION) 



1. Adrenalin (adrenin, epinephrine) — Increases glucose 

 (sugar) of blood, heart rate, and blood pressure; in 

 emotional stress the increased secretion may result in 

 increased blood pressure and heart action, increased 

 glucose production by the liver, increased saliva secre- 

 tion, dilation of eye pupil, increased rate of blood co- 

 agulation, paleness of skin because arteries in it decrease 

 in size 



Produced by the Islands of Langerhans: 



1. Insulin — Regulates glucose (sugar) metabolism and 

 decreases blood sugar; deficiency causes sugar diabetes 

 (excess sugar in blood and urine) 



2. Lipocaic — Regulates fat metabolism in liver 



