1. R.Arulmoli Gross anatomy of Endocrine glands: Pituitary,adrenal,thyroid and parathyroid glands

2. Learning objectives  Explain the location,parts,relations,hormones & blood supply of pituitary gland.  Differentiate the anterior and posterior pituitary.  Describe the location, relations,hormones, blood supply & lymphatic drainage of adrenal gland.  Explain the location,parts,coverings,relations,hormones & blood supply and lymphatic drainage of thyroid gland.  Outline the surgical anatomy of thyroid gland.  Describe the relations, blood supply, hormones & lymphatic drainage of parathyroid gland.

3.  Endocrine glands are ductless glands which secrete their hormones into blood directly.  The endocrine glands are : -Pituitary gland -Thyroid gland - Parathyroid gland - Adrenal gland - Pineal gland -Islets of pancreas.  Testes & ovaries are considered part of endocrine system. Endocrine glands

4. Pituitary gland

5.  Pituitary gland or hypophysis cerebri, is an neuroglandular body suspended from floor of 3rd ventricle by a stalk, infundibulum.  It is called the master gland since it controls the other endocrine glands.

6. Pituitary gland Location :  Situated in the hypophysial fossa, a bony depression in the sella turcica of body of sphenoid bone.  Lined by the dura mater and covered by a portion of the dura mater, diaphragma sellae.

7. Pituitary gland Measurements:  The gland measures approximately 1cm x 1 to 1.5cm, and 0.5cm thick.  Weight : 0.5gm in men and slightly more in women. Parts: 2 parts which differ from each other embryologically,morphologically and functionally.  1. Adenohypophysis ( Anterior pituitary): a. Pars distalis (pars anterior) b. Pars intermedia c. Pars tuberalis  2. Neurohypophysis (Posterior pituitary): a. Median eminence b. Infundibulum c. Pars nervosa

8. Pituitary gland - Relations  Superior: - Optic chiasma, - Diaphragma sella, - Anterior communicating artery, - Floor of 3rd ventricle.  Inferior : - Hypophyseal fossa, - Sphenoidal air sinus.  Anterior - Anterior intercavernous sinus.  Posterior - Posterior intercavernous sinus.  Lateral - Cavernous sinus and its related structures.

9. Pituitary gland X ray skull-lateral view

10. Pituitary gland Arterial supply:  Two pairs of arteries from the internal carotid artery. 1. Superior hypophyseal artery supplies pars tuberalis & infundibulum and form primary capillary plexus in median eminence. 2. Inferior hypophyseal artery supplies posterior lobe.

11. Pituitary gland Hypophyseal portal veins  Primary capillary plexus are fenestrated,transport neuro secretory hormones,synthesized in hypothalamus.  Stored in median eminence  Primary capillary plexus (median eminence)  Hypophyseal portal vein  Through infundibulum  Secondary capillary plexus ( anterior lobe - pars distalis)  Cavernous & intercavernous sinus.From here the neuro secretory hormones leave the blood to target organs.  Thus the hypophyseal portal system is the vascular system that is used for the hormonal regulation of pars distalis by the hypothalamus.

12. Pituitary gland Hypothalamo hypophyseal tract:  Axons of neurosecretory cells of supra optic (SO) and paraventricular (PV) nuclei of hypothalamus extend into the posterior pituitary as the hypothalamo hypophyseal tract.  The neurosecretory cells of supra optic and paraventricular secrete two hormomes: 1 Oxytocin 2. Vasopressin (ADH).  These two hormones are transported to the pars nervosa by the hypothalamo hypophyseal tract.

13. Pituitary gland Hormones :  Anterior pituitary secretes – Growth hormone ( GH ) Adrenocorticotropic hormone ( ACTH ) Prolactin Thyroid stimulating hormone ( TSH ) Follicle stimulating hormone ( FSH ) Luteinising hormone ( LH )  Posterior pituitary elaborates – Oxytocin Vasopressin (ADH)

14. Pituitary gland- Surgical anatomy Pituitary tumors:  Most pituitary tumors can be removed surgically trans sphenoidally.  The approach is through nose and sphenoidal sinus.

15. Adrenal gland

16.  Situation - Superomedial aspects of the kidney.  Separated from it by the little fatty connective tissue but the glands are enclosed in the renal fascia.  Height : 50mm  Breadth : 30mm  Thickness : 10mm  Weight : About 5 gm in adult.

17. Adrenal gland  The right adrenal is pyramidal in shape. Presents apex, base, anterior and posterior surfaces lateral and medial borders.  The left adrenal is semilunar in shape. Presents upper,lower ends,anterior,posterior surfaces,and medial and lateral borders.  Each consist of two parts, the outer cortex and inner medulla.

18. Adrenal gland - Relations Right suprarenal gland- Pyramidal shape.  Base is related to upper pole of right kidney.  Anterior surface related to liver laterally, inferior vena cava medially and occasionally duodenum inferiorly.  Posterior surface related to the right crus of diaphragm.

19. Adrenal gland - Relations Left suprarenal gland - semilunar in shape.  Anterior surface -related to cardiac end of stomach, splenic artery, pancreas.  Posterior surface -related to kidney laterally and left crus of diaphragm medially.

20. Adrenal gland - Hormones  Adrenal cortex secretes – Glucocorticoids - Cortisol Mineralocorticoids - Aldosterone Sex steroids - Testosterone  Adrenal medulla elaborates – Epinephrine Norepinephrine

21. Adrenal gland - Blood supply Artery- 3 arteries:  Superior suprarenal artery arise from the inferior phrenic artery.  Middle suprarenal artery arise from the abdominal aorta.  Inferior suprarenal artery arise from the renal artery. Veins- 1 vein:  Right suprarenal vein drain into Inferior vena cava.  Left suprarenal vein drain into left renal vein. Nerve supply:  Rich nerve supply from the celiac plexus and thoracic splanchnic nerves.

22. Adrenal gland - Arterial supply  Three arteries– Superior suprarenal artery is from inferior phrenic artery. Middle suprarenal artery is from aorta. Inferior suprarenal artery is from renal artery.

23. Adrenal gland - venous drainage Single vein:  On the right side drains into inferior vena cava.  On the left side drains into left renal vein.

24. Adrenal gland - Lymphatic drainage:  Lymphatics emerge out from the hilum of the suprarenal and drain into lateral aortic lymph nodes or lumbar lymph nodes.

25. Thyroid gland Oprah Winfrey George Bush

26. Thyroid gland Location:  Lower part of front and sides of neck opposite C5,6 & 7. Parts:  Two right and left lateral lobes, which extend from middle of thyroid cartilage to 4 th tracheal ring.  Joined by central isthmus which extends from 2-3 tracheal rings.  Sometimes a third pyramidal lobe may project upward from the isthmus.

27. Thyroid gland Coverings (capsules):  Inner true capsule is formed by condensation of connective tissue.  Outer false capsule, derived from pretracheal fascia of deep cervical fascia. Suspensory ligament of Berry:  Thickened false capsule that connects medial surface of lateral lobe to cricoid cartilage.  This ligament moves thyroid swellings upwards during swallowing.

28. Thyroid gland-Relations Lobes- are conical having apex,base and 3 surfaces - lateral,medial and posterolateral. Lateral surface:  Sternothyroid, sternohyoid,  superior belly omohyoid,  sternocleidomastoid. Medial surface:  2 tubes: Trachea, oesophagus.  2 muscles:Inferior constrictor,cricothyroid.  2 nerves:External laryngeal,recurrent laryngeal. Postero lateral surface:  Carotid sheath and common carotid artery.

29. Thyroid gland-Relations Isthmus – 2 surfaces:  Anterior surface - related to sternohyoid and sternothyroid muscles.  Posterior surface - related to 2 nd and 3 rd tracheal rings.

30. Thyroid gland - Hormones  Follicular cells secrete – T3 – Tri iodothyronine T4 – Tetra iodothyronine (Thyroxine)  Parafollicular cells secrete – Calcitonin

31. Thyroid gland - Arterial supply  Superior and inferior thyroid arteries.  Thyroidea ima (when present) originates from aortic arch or brachiocephalic trunk, enters the thyroid at inferior border of isthmus.

32. Thyroid gland - Arterial supply Superior thyroid artery:  First anterior branch external carotid artery.  Descends laterally to the larynx under the omohyoid and sternohyoid muscles.  Runs superficially on the anterior border of the lateral lobe, sending a branch deep into the gland before curving toward the isthmus where it anastomoses with the opposite artery.

33. Thyroid gland - Arterial supply Inferior thyroid artery:  Arise from thyrocervical trunk, a branch of subclavian artery.  Inferior thyroid artery ascends vertically and then curves medially to enter the tracheoesophageal groove (posterior to carotid sheath).  Branches penetrate the posterior aspect of the lateral lobe.

34. Thyroid gland - Arterial supply  Superior thyroid artery is closely related to external laryngeal nerve.  Inferior thyroid artery is closely related to recurrent laryngeal nerve.  Surgical importance: Careful ligation in thyroid surgery.

35. Thyroid gland - Venous drainage  3 pairs of veins: 1.Superior thyroid vein – ascend along superior thyroid artery and drains into the internal jugular vein. 2.Middlle thyroid vein – directly lateral and drains into the internal jugular vein. 3.Inferior thyroid vein (variable):  Right – drainage  right or left brachiocephalic vein.  Left – drainage  left brachiocephalic vein.

36. Thyroid gland Lymphatic drainage:  Prelaryngeal,pretracheal and paratracheal lymph nodes. Nerve supply: Principally from autonomic nervous system.  Parasympathetic – from vagus  Sympathetic – from superior, middle, and inferior ganglia of the sympathetic trunk Enter the gland along with the blood vessels.

37. Thyroid gland- Clinical importance Goiters are swellings of thyroid gland due to iodine deficiency. Major clinical symptoms of goiter: 1.Dysphagia (difficulty in swallowing) 2.Dyspnoea (difficulty in breathing) 3.Hoarseness of voice (change in voice) The relations of thyroid gland (trachea, esophagus and recurrent laryngeal nerve) and its compression effects.

38. Large goiters are prevalent in areas of iodine deficiency. A woman from Switzerland operated upon by Dr. Theodor Kocher (From Kocher T: Zur pathologie und therapie deKropfes (parts I and 2). Dtsch Z Chir 4, 1874 ) A B One hundred years later, large goiters still occur in many parts of the world, as demonstrated in this woman from a mountainous region of Viet Nam, 1970. Thyroid gland- Goiter

39. Normal anatomy of the recurrent laryngeal nerve. A) Note that on the right side the recurrent laryngeal nerve hooks around behind the subclavian artery. while on the left side this nerve passes around behind the aortic arch before ascending in the neck. B) When there is a vascular anomaly of the right subclavian artery, the recurrent laryngeal nerve no longer "recurs" around this artery but proceeds from the vagus nerve in a more transverse direction to the larynx. In such a situation, the nerve is much more likely to be damaged during surgery unless care is taken to visualize its course in the neck. Thyroid gland- Surgical anatomy

40. The location of 204 recurrent laryngeal nerves in dissection of 102 cadavers. Note that the recurrent laryngeal nerve was found anterior to the tracheoesophageal groove in 42 percent of cases and within the thyroid gland in 3 percent (8 cases). In both of these locations, the nerve is more prone to be damaged if its course is not carefully visualized by the surgeon. Thyroid gland- Surgical anatomy

41. The thyroid lobe is retracted medially the recurrent laryngeal nerve, the inferior thyroid artery and the parathyroid glands are identified. The inferior thyroid artery is not ligated laterally as a single trunk. Rather, each small branch is ligated and divided at a point distal to the parathyroid glands (see arrows in insert) in order to preserve their blood supply. The thyroid lobe can then be removed from its tracheal attachments if a lobectomy is to be performed. Thyroid gland- Surgical anatomy

42. The dramatic case of Maria Richsel, the first patient to have come to Kocher’s attention with postoperative myxedema following total thyroidectomy. A.Maria and her younger sister before the operation. B.The changes nine years after the operation. The younger sister, with the dwarfed and stunted growth. Also note Maria’s thickened face and fingers, which are typical of myxedema. Because of this and other patients with the same problem, Kocher stopped performing total thyroidectomies. For this work, demonstrating the physiological importance of the thyroid gland in man, Professor Kocher was awarded the Nobel prize. Thyroid gland- Surgical anatomy A B

43. (A). Lingual thyroid is seen in the back of the tongue. (B). On thyroid scan, radioiodine uptake is present only in the lingual thyroid, demonstrating that no thyroid tissue is present in its normal cervical location. Thyroid gland- Congenital anomaly

44. Parathyroid gland

45.  Two pairs, lies in the posterior part of thyroid gland,within the pretracheal fascia.  Size: 6x4x2 mm. Weight- 50 mg.  Identification: Close to the anastomosis of superior & inferior thyroid arteries.

46. Parathyroid gland - Hormone  Parathyroid gland secretes – Parathormone which controls the metabolism of calcium and phosphorus along with calcitonin.

47. Parathyroid gland  Blood supply : Inferior thyroid artery.  Veins and lymphatics are associated with that of thyroid gland.  Nerves – Sympathetic & parasympathetic.

48. Summary

49. Pituitary gland

50. Adrenal gland

51. Thyroid gland Location,capsules,relations and blood supply. The relations of thyroid gland (trachea, esophagus and recurrent laryngeal nerve) and its compression effects.

52. Parathyroid gland

53. Any questions ?

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