Page 1 of 6 you sort of start thinking anythings possible if youve got enough nerve Ginny WeasleyAlyssaWillis L. Ng, 1A, A.Y. 2014-2015 Far Eastern UniversityNicanor Reyes Medical Foundation Gross HSB B Pituitary, Pineal, Thyroid, Parathyroid Glands Dr. Capulong (Nov. 3, 2014) Endocrine System consists of specialized structures that secrete hormones, including: odiscrete ductless endocrine glands oisolated and clustered cells of the gut and blood vessel walls ospecialized nerve endings its influence is broadly distributed like the nervous system hormones oorganic molecules ocarried by circulatory system to distant effector cells in all parts of the body oinfluence metabolism and other processes (e.g. menstrual cycle, pregnancy, parturition) two most important endocrine glands opituitary gland othyroid gland mostly located in head and neck area opituitary gland opineal gland othyroid gland oparathyroid gland glands are well distributed ohead, neck, torso, abdominal and even genital areas Pituitary gland also called the hypophysis cerebrireferred as the master endocrine gland due to its influence on many other endocrine glands vital to life small, oval structure; 1 cm in size x-ray: non-illuminating gland, however the shadow of the sphenoid sinus and hypophysial fossa can be seen attached to the undersurface of the brain by infundibulum well protected due to its location location: omiddle cranial fossa osella turcica (L. Turkish saddle)bony formation on the upper surface of the sphenoids body composed of three parts: tuberculum sellae (horn of saddle) hypophysial fossa (pituitary fossa) omedian seat of depression (seat of saddle) oaccommodates pituitary gland dorsum sellae (back of saddle) parts: oanterior lobe or adenohypophysis glandular in nature; synthesizes & secretes hormones three parts: pars distalis or pars anterior olargestpars tuberalis oextends up along the anterior and lateral surfaces of the pituitary stalk/infundibulum omistaken as part of infundibulum pars intermedia obet. anterior & posterior pituitary lobes oposterior lobe or neurohypophysis neural in nature; stores & secretes hormones direct communication to the base of the brain via the infundibulum or the hypothalamo-hypophyseal tract relations oanterior: sphenoid sinus oposterior: dorsum sellae basilar artery pons osuperior: diaphragma sellae smallest dural infolding suspended bet. clinoid processes partial roof over the hypophysial fossa in sphenoid has aperture for passage of infundibulum and hypophysial veins separates anterior lobe from optic chiasma optic chiasma oinferior: body of sphenoid and sphenoid air sinuses olaterally: cavernous sinus and its contents (refer to plate below) impt. structures: ICA, abducent nerve Page 2 of 6 you sort of start thinking anythings possible if youve got enough nerve Ginny WeasleyAlyssaWillis L. Ng, 1A, A.Y. 2014-2015 blood supply (check plate 141, Netter) oanterior pituitary lobe has dual blood supplysuperior hypophyseal artery comes from internal carotid arteries hypophyseal portal system formed by a series of capillary network releasing and inhibiting hormones pass through here (hypothalamus pituitary) oposterior pituitary lobe inferior hypophyseal artery comes from internal carotid arteries drainage ointercavernous sinuses (Snell, p. 654) ocavernous sinus (lec) one of the larger draining sinuses in the cranial cavity function oinfluences activities of many other endocrine glands oit is itself controlled by the hypothalamus oactivities of the hypothalamus are modified by information received along numerous nervous afferent pathways from various parts of the CNS plasma levels of circulating electrolytes and hormoness abnormalities osigns and symptoms visual defects due to close proximity to the optic chiasma thrombosis due to impedance or decrease of blood flow in cavernous sinus increase in intracranial pressure due to pressure of the pituitary gland to the cavernous sinus hormones oanterior pituitary lobe synthesizes and secretes its own hormones HormoneAb-brev. Target organs FunctionNotes Growth Hormone GHBones and muscles Devt of bones and muscles ProlactinPRLMammary glands Stimulate and maintain milk production Reproductive hormones; Stimulated by latching Follicle-stimulating hormone FSHTestes or ovaries Follicular development in ovaries;Sperm development in testes Reproductive hormones; Very evident during puberty Luteinizing Hormone LHTestes or ovaries Triggers ovulation; Stimulates testosterone production Thyrotro-pic Hormone TSHThyroidInfluence growth and activity of the thyroid gland General metabolic hormone; governed by (-) feedbackAdreno-cortico-tropic Hormone ACTHAdrenal cortex Increase secretion of cortisol; Increase skin pigmentation Very evident during pregnancy (dark coloured necks and armpits) clinical correlation Gigantism [growth hormone] oexcessive growth hormonal production before closure of epiphyseal plates omanifestations: symmetrical/proportional enlargement extremely tall Acromegaly [growth hormone] oexcessive growth hormonal production after closure of epiphyseal plates omanifestations: asymmetrical/disproportional enlargement abnormally large hands and feet large embossed forehead Cushings syndrome [ACTH] osuprarenal cortical hyperplasia most common cause oadenoma or carcinoma of the cortex if syndrome occurs in later life omanifestations: moon-shaped or puffing face truncal obesity abnormal hairiness (hirsutism) hypertension edema-like features humpback features Simmonds disease (Panhypopituitarism) oexcessive growth of chromophobes microscopically, the pituitary gland has: acidophils basophilschromophobes odecrease or absent hormonal production oall anterior pituitary hormones are affected omanifestations: hypothyroidism hypoadrenocorticalism hypogonadism dwarfism otreatment: supplement exogenous hormones Pituitary gland enlargement/Pituitary tumor omanifestations: same as abnormalities otreatment: removal of pituitary gland done by transsphenoidal surgery via the nasal cavity obefore: big incision/craniotomy elevate the brain and gain access to base of the brain oposterior pituitary lobe acts as storage/reservoir or extension of hypothalamus HormoneAb-brev. Target organs Function OxytocinUterine muscles; Mammary glands Stimulates contraction of uterus during labor (augments labor); Causes milk ejection during latching Anti-Diuretic Hormone/ Vasopressin ADHKidney tubules Can inhibit urine production; In large amounts, can cause vasoconstriction increased blood pressure Page 3 of 6 you sort of start thinking anythings possible if youve got enough nerve Ginny WeasleyAlyssaWillis L. Ng, 1A, A.Y. 2014-2015 clinical correlation Oxytocin oduring labour, commercially prepared oxytocin may be given intravenously onaturally, it can also be increased through nipple stimulation since during pregnancy, there is heightened hormonal release osex during pregnancy is allowed; however, dont stimulate the nipple to avoid premature uterine contraction Pineal Gland opposite side of the pituitary gland small cone-shaped body consists of pinealocytes, supported by glial cells location: oposterior end of the roof of the third ventricle of the brain innervations: opostganglionic sympathethic nerve fibers has a rich blood supply function: oinhibitory effect on other endocrine glands pituitary gland pancreatic islets of Langerhans of the pancreas thyroid gland parathyroid gland adrenal glands gonads obefore: thought to only have an effect in circadian rhythmpineal secretions oreach target organs via: blood stream cerebrospinal fluid oactions: mainly inhibitory directly inhibit production of hormones indirectly inhibit secretion of releasing factors by the hypothalamus very evident during early childhood to teen years oCT scan or MRI: can see the glands outline degenerates during adulthood (20s onwards) oCT scan or MRI: cannot see any trace of pineal gland, except of calcifications on the area of the pineal gland Thyroid Gland vascular organ usually described as a butterfly shape (lobes wings, isthmus body) bodys largest endocrine gland surrounded by a sheathoderived from pretracheal layer of deep fascia oattaches the gland to the larynx and trachea location: odeep to the sternothyroid and sternohyoid muscles olocated anteriorly in the neck at the level of C5-T1 vertebrae parts: oright lobe pear shaped apex: upward, as far as oblique line on lamina of thyroid cartilage base: lies below (level of fourth or fifth tracheal ring) oleft lobe characteristics same as right lobe oisthmus narrow connects right and left lobes over the trachea extends across the midline in front of the second, third, and fourth tracheal rings opyramidal lobe often present; 50% of individuals projects upward from isthmus, usually to the leftusually connected to the hyoid bone by a fibrous or muscular band if muscular, it is called levator glandulae thyroideae relations: olobes anterolaterallysternothyroid superior belly of omohyoid sternohyoid anterior border of sternocleidomastoid Page 4 of 6 you sort of start thinking anythings possible if youve got enough nerve Ginny WeasleyAlyssaWillis L. Ng, 1A, A.Y. 2014-2015 posterolaterally carotid sheath with: ocommon carotid artery ointernal jugular vein ovagus nerve medially larynx trachea pharynx esophagus associated with the abovementioned structures are: ocricothyroid muscle and its nerve supply oexternal laryngeal nerve assoc with superior pole of the thyroid orecurrent laryngeal nerve assoc w/ paraverterbral, posterior part of the thyroid*posterior border of each lobe is related posteriorly to the superior and inferior parathyroid glands and anastomosis bet. superior and inferior thyroid arteries oisthmus anteriorly sternothyroids sternohyoids anterior jugular veins fascia skin posteriorly second, third, and fourth rings of the trachea **superior thyroid arteries branches anastomose along isthmus upper border functions: oaffects all areas of the body except itself, spleen, testes, and uterus oproduces thyroid hormone controls rate of metabolic activity of most cells in the body triiodothyronine (T3) conversion of T4 at target tissues active form of thyroid hormone thyroxine (T4)secreted by thyroid follicles storage form of thyroid hormoneoproduces calcitonin or thyrocalcitonin produced by C (parafollicular) cells controls calcium metabolism lowers the level of blood calcium by causing calcium deposition on bone antagonistic to parathyroid hormone affected by menopause (decrease activity; promote osteoporosis) clinical correlation: ohypothyroidism decrease in thyroid hormone concentration causes cretinism (esp. if patient is child or pregnant woman can be shared to the child) signs and symptoms: increase in weight tendency to be sleepy ohyperthyroidism increase in thyroid hormone concentration signs and symptoms: absence in weight gain tremors and palpitations causes Graves Disease development: othyroid starts at the base of the tongue osubsequently go down to the anterior neck area ohas communication in the form of the foramen cecum sometimes it does not close, even during adult years if patent, can have formation of thyroglossal duct cyst this is due to the constant filling up of saliva and food particles through time manifested as an anterior neck mass oto check if it is TDC: when patient swallows, thyroid gland moves up and down, because it is attached to tracheal rings when patient sticks the tongue out and in, thyroglossal duct cyst will move up and down because communication is in the base of the tongue blood supply: osuperior thyroid artery* first branch of external carotid artery descends to the superior pole of each lobe pierce the pretracheal layer of deep cervical fascia divide into anterior and posterior branches supply mainly anterosuperior aspect of the gland accompanied by external laryngeal nerve Page 5 of 6 you sort of start thinking anythings possible if youve got enough nerve Ginny WeasleyAlyssaWillis L. Ng, 1A, A.Y. 2014-2015 oinferior thyroid artery* largest branch of thyrocervical trunk from the subclavian arteries ascends behind the gland to the level of the cricoids cartilage turns medially and downward to reach posterior border of the gland divide into several branches that pierce pretracheal layer of the deep cervical fascia supply posteroinferior aspect including inferior poles of the gland recurrent laryngeal nerve crosses either in front of or behind the artery or pass between its branches *right and left superior and inferior thyroid arteries anastomose profusely over the surface of the gland to ensure supply and provide potential collateral circulation bet. subclavian and external carotid arteries osometimes, thyroidea ima (12% of people [lec], ~10% [Moore]) branch of the brachiocephalic artery or aortic archmay also arise from the right common carotid, subclavian, or internal thoracic arteries (Moore, p.1018) ascends in front of trachea to the isthmus, where it divides blood drainage: osuperior thyroid vein** internal jugular vein accompany the superior thyroid arteries drain superior poles of the thyroid gland omiddle thyroid vein** internal jugular vein do not accompany but run parallel courses with inferior thyroid arteries drain middle of the lobes in doing thyroidectomy, one of the very important steps is to ligate and cut it to prevent bleeding oinferior thyroid vein** brachiocephalic vein usually independent drain inferior poles veins from two sides anastomose with one another as they descend in front of the trachea **three pairs of thyroid veins usually form a thyroid plexus of veins lymph drainage odrains mainly laterally into the deep cervical lymph nodes (Snell, p. 658) oa few lymph vessels descend to the paratracheal nodes olymphatic vessels run in interlobular connective tissue, usually near arteries and communicate with network of lymphatic vessels (Moore, p. 1020) vessels pass initially to prelaryngeal, pretracheal, and paratracheal lymph nodesprelaryngeal superior deep cervical lymph nodes pretracheal and paratracheal inferior deep cervical lymph nodes lymphatic vessels located along superior thyroid veins pass directly to inferior deep cervical lymph nodes some drain into brachiocephalic lymph nodes or the thoracic duct nerve supply onerves superior cervical sympathetic ganglia middle cervical sympathetic ganglia inferior cervical sympathetic ganglia onerves reach the gland through cardiac plexuses superior thyroid peri-arterial plexuses inferior thyroid peri-arterial plexuses ovasomotor, not secremotor oendocrine secretion from thyroid gland is hormonally regulated by pituitary gland Parathyroid Gland ovoid bodies 6 mm long greatest diameter four in number o~5% of people have more osome have only two glands location: oclosely related to posterior border of the thyroid gland olies within thyroid glands fascial capsule otwo superior parathyroid glands more constant in position lie at the level of the midline of the posterior border of the thyroid gland usually lie slightly >1 cm superior to the pt. of entry of the inferior thyroid arteries into the thyroid gland usually at the level of the inferior border of the cricoid cartilage otwo inferior parathyroid glands usually lie close to inferior poles of the thyroid gland usually lie slightly >1 cm inferior to the arterial entry pt. may lie: within fascial sheath embedded in the thyroid substance outside the fascial sheath sometimes: found some distance caudal to the thyroid gland in association with inferior thyroid veins in superior mediastinum in the thorax (1-5% of people) function: osecrete parathyroid hormone produced by chief cells stimulates osteoclastic activity in bones mobilizes bone calcium increases calcium levels in blood stimulates absorption of dietary calcium from small intestine stimulates reabsorbtion of calcium in proximal convoluted tubules of the kidney strongly diminishes reabsorption of phosphate in PCT of kidney osecretion is controlled by calcium levels in the blood olow levels of calcium can cause muscle cramps or tetany Page 6 of 6 you sort of start thinking anythings possible if youve got enough nerve Ginny WeasleyAlyssaWillis L. Ng, 1A, A.Y. 2014-2015 blood supply: osuperior thyroid arteries oinferior thyroid arteries blood drainage osuperior thyroid veins omiddle thyroid veins oinferior thyroid veins lymph drainage: odeep cervical lymph nodes oparatracheal lymph nodes nerve supply: osuperior cervical sympathetic ganglia omiddle cervical sympathetic ganglia clinical correlation othyroidectomy may inadvertently remove parathyroids because they are hard to identify (look like fat tissues in normal persons) oextracapsular thyroidectomy to leave behind the posterior capsule of the thyroid ensures that parathyroids are left behind oif removed: can cause hypocalcemia lifelong problem signs and symptoms: Chvostek sign otapping cheek causes uncontrollable facial movements carpopedal spasm ofingers and toes are rigid to correct: implant parathyroids in a site with very good blood supply create a subcutaneous pocket for parathyroids Quotes Of course, there are instances wherein that [latching] is not enough to stimulate milk production. You can either use the breast pump or thats where the husband comes in. Di ko sinabing mag-latch yung tatay. Just to stimulate the nipple. If you want to have a sexual act, please do not touch the nipple. Please do not touch the breast. Be creative.