dr. sami zaqout faculty of medicine iug

Dr. Sami Zaqout Faculty of Medicine IUG


Pituitary Gland - Parts


Pituitary Gland - Relations

Dr. Sami Zaqout


Pituitary Gland - Relations


Pituitary Gland - Blood Supply

• The arteries are derived from:

– Superior hypophyseal artery

– Inferior hypophyseal artery

• The veins drain into:

– Intercavernous sinuses


Pituitary Gland - Functions

The master endocrine gland


Pineal Gland


Pineal Gland - Functions

• Can influence the activities of: – Pituitary gland

– Islets of Langerhans of the pancreas

– Parathyroids

– Adrenals

– Gonads

• The pineal secretions actions are mainly inhibitory and either directly inhibit the production of hormones or indirectly inhibit the secretion of releasing factors by the hypothalamus.


Thyroid Gland


Thyroid Gland - Capsules


Thyroid Gland - Relations


Arteries of the thyroid gland

external carotid artery

superior thyroid artery

external laryngeal

nerve

thyrocervical trunk

inferior thyroid artery

recurrent laryngeal

nerve

arch of the aorta

thyroidea ima


Veins of the thyroid gland

Superior

thyroid vein

Middle

thyroid vein

internal jugular vein

Inferior

thyroid vein

left brachiocephalic

vein


Thyroid Gland - Lymph Drainage

• Drains mainly laterally into the deep

cervical lymph nodes.

• A few lymph vessels descend to the

paratracheal nodes.


Thyroid Gland - Nerve Supply

• Superior cervical sympathetic ganglia

• Middle cervical sympathetic ganglia

• Inferior cervical sympathetic ganglia


Thyroid Gland - Funcions

The thyroid hormones, thyroxine and

triiodothyronine, increase the metabolic

activity of most cells in the body.

The parafollicular cells produce the

hormone thyrocalcitonin, which lowers the

level of blood calcium.


Swellings of the Thyroid Gland and

Movement on Swallowing • The thyroid gland is invested

in a sheath derived from the pretracheal fascia.

• This tethers the gland to the larynx and the trachea and explains why the thyroid gland follows the movements of the larynx in swallowing.

• Any pathologic neck swelling that is part of the thyroid gland will move upward when the patient is asked to swallow.


The Thyroid Gland and the Airway

• The close relationship

between the trachea and

the lobes of the thyroid

gland commonly results in

pressure on the trachea in

patients with pathologic

enlargement of the thyroid.


Retrosternal Goiter

• A retrosternal goiter can

compress the trachea and

cause dangerous dyspnea; it

can also cause severe

venous compression.


Thyroglossal Cyst

• Cysts may occur at any point along the thyroglossal tract.

• They occur most commonly in the region below the hyoid bone.

• Such a cyst occupies the midline and develops as a result of persistence of a small amount of epithelium that continues to secrete mucus.

• As the cyst enlarges, it is prone to infection and so it should be removed surgically.

• Since remnants of the duct often traverse the body of the hyoid bone, this may have to be excised also to prevent recurrence.


Thyroglossal Sinus (Fistula)

• Occasionally, a thyroglossal

cyst ruptures spontaneously,

producing a sinus.

• Usually, this is a result of an

infection of a cyst. All

remnants of the thyroglossal

duct should be removed

surgically.


Thyroidectomy and the Parathyroid Glands

• In partial thyroidectomy, the posterior part of the thyroid gland is left undisturbed so that the parathyroid glands are not damaged.

• it is not uncommon for the surgeon to find the inferior parathyroid glands in the superior mediastinum because they have been pulled down into the thorax by the thymus.


Parathyroid Glands


Parathyroid Glands

• Blood Supply

– The arterial supply to the parathyroid glands is

from the superior and inferior thyroid arteries.

– The venous drainage is into the superior, middle,

and inferior thyroid veins.

• Lymph Drainage

– Deep cervical and paratracheal lymph nodes.

• Nerve Supply

– Superior or middle cervical sympathetic ganglia.


Functions of the Parathyroid Glands

The chief cells produce the parathyroid hormone, which stimulates osteoclastic activity in bones, thus mobilizing the bone calcium and increasing the calcium levels in the blood.

The parathyroid hormone also stimulates the absorption of dietary calcium from the small intestine and the reabsorption of calcium in the proximal convoluted tubules of the kidney.

It also strongly diminishes the reabsorption of phosphate in the proximal convoluted tubules of the kidney.

The secretion of the parathyroid hormone is controlled by the calcium levels in the blood.

dr. sami zaqout faculty of medicine iug

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