Dr. Sami Zaqout Faculty of Medicine IUG
Transcript of Dr. Sami Zaqout Faculty of Medicine IUG
Dr. Sami Zaqout Faculty of Medicine IUG
Pituitary Gland - Blood Supply
• The arteries are derived from:
– Superior hypophyseal artery
– Inferior hypophyseal artery
• The veins drain into:
– Intercavernous sinuses
Dr. Sami Zaqout Faculty of Medicine IUG
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.
Dr. Sami Zaqout Faculty of Medicine IUG
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
Dr. Sami Zaqout Faculty of Medicine IUG
Veins of the thyroid gland
Superior
thyroid vein
Middle
thyroid vein
internal jugular vein
Inferior
thyroid vein
left brachiocephalic
vein
Dr. Sami Zaqout Faculty of Medicine IUG
Thyroid Gland - Lymph Drainage
• Drains mainly laterally into the deep
cervical lymph nodes.
• A few lymph vessels descend to the
paratracheal nodes.
Dr. Sami Zaqout Faculty of Medicine IUG
Thyroid Gland - Nerve Supply
• Superior cervical sympathetic ganglia
• Middle cervical sympathetic ganglia
• Inferior cervical sympathetic ganglia
Dr. Sami Zaqout Faculty of Medicine IUG
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.
Dr. Sami Zaqout Faculty of Medicine IUG
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.
Dr. Sami Zaqout Faculty of Medicine IUG
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.
Dr. Sami Zaqout Faculty of Medicine IUG
Retrosternal Goiter
• A retrosternal goiter can
compress the trachea and
cause dangerous dyspnea; it
can also cause severe
venous compression.
Dr. Sami Zaqout Faculty of Medicine IUG
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.
Dr. Sami Zaqout Faculty of Medicine IUG
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.
Dr. Sami Zaqout Faculty of Medicine IUG
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.
Dr. Sami Zaqout Faculty of Medicine IUG
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.
Dr. Sami Zaqout Faculty of Medicine IUG
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.