Endocrine Flashcards
The two endocrine structure in the endocrine system that are located in the head
Pituitary gland and the pineal gland
The five additional structures of the endocrine system and are situated in the neck
Thyroid gland 1
Parathyroid gland 4
___ is a small, oval structure attached to the undersurface of the brain by the stalk like ____
Pituitary gland
Infundibulum
The infundibulum pierces the ____ to reach the gland
Diaphragma sellae
The gland itself is well protected by virtue of its location in the ______ of the ______ of the sphenoid bone.
Hypophyseal fossa
Sella turcica
the hypophysis cerebri is often referred to as the?
Master endocrine gland
What are the two lobes of the pituitary gland
Anterior lobe (adenohypophysis)
Posterior lobe (neurohypophysis)
The anterior lobe is subdivided into the _____ and the ____ which may be separated by a cleft that is a remnant of an embryonic pouch
Pars anterior (sometimes called pars distalis)
Pars intermedia
A projection from the pars anterior, the _______ , extends up along the anterior and lateral surfaces of the pituitary stalk.
Pars tuberalis
Relation of pituitary gland:
Anterior: ?
Posterior:?
Superior:?
Inferior:?
Lateral:?
A - sphenoid sinus
P - dorsum sellae, basillar A. Pons
S - diaphragma sella has a central aperture that allows the passage of the infundibulum and separates the anterior lobe from the optic chiasma
I - Body of the sphenoid, with its sphenoid air sinuses
L - cavernous sinus and its contents.
Blood supply of the pituitary
Artery?
Vein?
A - Superior and inferior hypophyseal A, branches if ICA
V - intercavernous sinuses
The ________ influences the activities of many other endocrine glands.
Pituitary gland
The pituitary gland is itself controlled by the ____
Hypothalamus
___ is a small cone-shaped body that projects posteriorly from the posterior end of the roof of the third ventricle of the brain
Pineal gland
The pineal consists essentially of groups of cells, the ___, supported by glial cells.
Pinealocytes
The pineal gland has a rich blood supply and is innervated by
Postganglionic sympathetic nerve fibers
Main function of pineal gland
Their actions are mainly inhibitory and either directly inhibit the production of hormones or indirectly inhibit the secretion of releasing factors by the hypothalamus.
What cell does the pineal gland secretes?
Pinealocytes
consists of right and left lobes connected by a narrow isthmus
Thyroid gland
a vascular organ surrounded by a sheath derived from the pretracheal layer of the deep fascia. The sheath attaches the gland to the larynx and the trachea.
Thyroid gland
The apex of each lobe of thyroid gland is directed upward as far as the ____ and its base lies below at the ___
Oblique line on the lamina of the thyroid cartilage
Level of fourth and fifth tracheal ring
The isthmus extends across the midline in front of the ___, ___, and ___ tracheal rings
Second, third and fourth
A ______ is often present, and it projects upward from the isthmus, usually to the left of the midline.
Pyramidal lobe
A fibrous or muscular band frequently connects the pyramidal lobe to the hyoid bone; if it is muscular, it is referred to as the?
Levator glandulae thyroideae
Relation of thyroid gland lobes
Anterolateral:
Posterolateral:
Medial:
Posterior:
A - Sternothyroid, superior belly of the omohyoid, sternohyoid, the anterior border of the sternocleidomastoid
P - Carotid sheath with the common carotid artery, internal jugular vein, and vagus nerve
M - the larynx, trachea, pharynx and esophagus
Superior and inferior parathyroid glands and the anastomosis between the superior and inferior thyroid arteries
Relation of thyroid gland isthmus
Anterior:
Posterior:
Superior:
A - sternothyroid, sternohyoid, ant jugular veins, fascia and skin
P - second, third, and fourth rings of the trachea
S - terminal branches of superior thyroid arteries anastomose along its upper border
The arteries of the thyroid gland are?
Superior thyroid artery, inferior thyroid A and sometimes the thyroidea ima.
____ a branch of the external carotid artery, descends to the upper pole of each lobe, accompanied by the external laryngeal nerve.
Superior thyroid artery
superior thyroid artery, a branch of the external carotid artery, descends to the upper pole of each lobe, accompanied by the _____
External laryngeal nerve
____ a branch of the thyrocervical trunk artery, ascends behind the gland to the level of the cricoid cartilage. It then turns medially and downward to reach the posterior border of the gland.
Inferior thyroid artery
What branch is the inferior thyroid artery?
Branch of thyrocervical trunk
The ____ crosses either in front f or behind the inferior thyroid artery, or it may pass between its branches
Recurrent laryngeal nerve
The ___ if present, may arise from the brachiocephalic artery or the arch of the aorta. It ascends in front of the trachea to the isthmus.
Thyroidea ima
Veins of the thyroid gland
Superior thyroid, middle thyroid and inferior thyroid.
Vein drainage of the thyroid glands
Superior thyroid - where?
Middle thyroid - where?
Inferior thyroid - where?
ST - internal jugular vein
MT - internal jugular vein
IT - inferior thyroid veins of the two sides anastomose with one another as they descend in front of the trachea
They drain into the left brachiocephalic vein in the thorax
Lymph drainage of the thyroid gland
Drains mainly laterally into the deep cervical lymph nodes.
Few lymph vessel descend to the paratracheal nodes
Nerve supply of thyroid gland
Superior, middle, and inferior cervical sympathetic ganglia.
Thyroid gland function
Secretes thyroxine and triiodothyronine, increases metabolic activity of most cells in the body. The parafollicular cells produce the hormone thyrocalcitonin, which lowers the level of blood calcium.
____ are ovoid bodies measuring about 6 mm long in their greatest diameter. They are four in number and are closely related to the posterior border of the thyroid gland, lying within its fascial capsule
Parathyroid glands
How many mm long is the parathyroid glands?
6mm
The two ___ parathyroid glands are the more constant in position and lie at the level of the middle of the posterior border of the thyroid gland.
Superior parathyroid glands
The two ___ parathyroid glands usually lie close to the inferior poles of the thyroid gland. They may lie within the fascial sheath, embedded in the thyroid substance, or outside the fascial sheath.
Inferior parathyroid gland
Sometimes, they are found some distance caudal to the thyroid gland, in association with the inferior thyroid veins, or they may even reside in the superior mediastinum in the thorax.
Inferior parathyroid glands
Blood supply (arteries and veins) of parathyroid glands
Superior and inferior thyroid arteries
Venous drainage is into superior, middle and inferior thyroid veins
Lymph drainage of parathyroid glands
Deep cervical and paratracheal lymph nodes
Nerve supply of parathyroid glands
Superior or middle cervical sympathetic ganglia
The function of 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.
Also stimulates the absorption of dietary calcium from the SI and the reabsorption of calcium in the proximal convoluted tubules of the kidney and Also strongly diminishes the reabsorption of phosphate
Calcium levels in the blood control the secretion of the parathyroid hormone
Pinealocytes is supported by what cell?
Glial cells
What separates the anterior lobe of the pituitary gland
Separated by a cleft that is a remnant of an embryonic pouch
