Endocrine System Flashcards
What is a “functioning” endocrine tumour?
May allow secretion of too much hormone
What are endocrine glands responsible for?
Manufacture, storage and release of at least 1 hormone
What is a “non-functioning” endocrine tumour?
A tumour that results in too little hormone being secreted
What is the diencephalon?
The central core of the cerebrum, with connections to the right and left hemispheres and the midbrain
Where is the hypothalamus?
Dienchephalon Diencephalon = thalamus + hypothalamus
Which lies superiorly, the thalamus or the hypothalamus?
Thalamus
Which structure lies inferiorly to the hypothalamus?
Brain stem - midbrain, pons, medulla
What nerves does the cribiform plate of the ethmoid bone transmit and what do they supply?
Olfactory - sense of smell
Which structure connects the hypothalamus to the pituitary gland?
Infundibulum
Where is the pituitary gland?
Midline structure in the pituitary fossa of the sphenoid bone
Which two hormones are produced by the axons of the hypothalamic neurones which pass into the posterior pituitary?
Oxytocin Vasopressin
What hormones are released from the anterior pituitary?
Growth hormone Prolactin Thyroid stimulating hormone Adrenocorticotrophic hormone Lutenising hormone Follicle stimulating hormone
What role does the hypothalamus play in regulation of secretions from the anterior pituitary?
Hypothalamic neurones secrete either releasing hormones to promote secretion or release-inhibitory neurones
Where do the hypothalamic neurones secrete their hormones into?
Hypophyseal portal system
Where does the blood from the anterior pituitary drain into?
Hypophyseal veins and to the SVC
Which gland is often referred to as the “master gland”?
Pituitary gland
What is a goitre?
An enlarged thyroid gland
Which chemical does the thyroid gland use to manufacture it’s hormones?
Iodine
What are the two hormones secreted by the thyroid gland?
Triiodothyronine Thyroxine
What do thyroid hormones regulate?
Metabolism Stimulation of growth
Where is the thyroid gland?
Attached to the thyroid cartilage superiorly Passes the cricoid cartilidge bilaterally Right and left lobe meet at the isthmus on the trachea
Where are the four parathyroid glands located?
The posterior surfaces of the thyroid glands lobes
What does the parathyroid gland secrete and what does this regulate?
Parathyroid hormone This regulates the amount of calcium in blood and bone
Which glands are under pituitary control?
Thyroid gland Adrenal cortex Gonads
What is the arterial supply of the thyroid and parathyroid glands?
Left and right, inferior and superior thyroid artery
What is the venous drainage of the thyroid and parathyroid glands?
Left and right, superior and inferior thyroid veins
What are the endocrine cells of the pancreas?
The islets of langerhans
Where are the adrenal glands?
Capping the superior ends of the kidneys
What are the two parts of the adrenal glands?
Adrenal medulla Adrenal cortex
What does the adrenal cortex secrete?
Glucocorticoids Mineralocorticoids Androgens
The secretion of which hormone from the adrenal cortex is under pituitary control?
Glucocorticoids
What hormones does the adrenal medulla secrete?
Adrenaline Noradrenaline
What arteries supply each adrenal gland?
Right and left superior suprarenal artery Right and left middle suprarenal artery Right and left inferior suprarenal artery
What are the three paired branches of the abdominal aorta?
Adrenal arteries Renal arteries Gonadal arteries
What is the venous drainage of the adrenal glands?
Right suprarenal vein - drains into the IVC Left suprarenal vein - drains into the left renal vein
Which structure does the pituitary gland lie immediately inferior to?
Optic chiasm
Which cranial nerve is the optic chiasm formed from?
CN2, right and left optic nerve
Which route do the optic tracts take once they have crossed in the optic chiasm?
They pass posteriorly from the optic chiasm, and after synapsing in the thalamus the next axons in the chain pass via the optic radiation to the visual cortex
Where is the visual cortex located?
Occipital lobe
What side of the visual field does the nasal retina get information from?
Temporal side
Where is information from the nasal side of the visual field detected?
The temporal retina
What effect might a pituitary tumour have on the visual pathway?
Bitemporal hemianopia
What is the transcranial approach to accessing the pituitary fossa surgically?
Getting access from the side, under the frontal lobe
What is the transsphenoidal approach to accessing the pituitary fossa surgically?
Getting access via the nasal cavities and the sphenoid sinus
How does the thyroid gland begin its development embyrologically?
It begins as a midline proliferation at the junction between the anterior 2/3rds of the tongue and the posterior 1/3
How does the thyroid gland continue it’s development embryologically (after proliferation at the tongue)?
It migrates inferiorly whilst remaining attached to the tongue via the thyroglossal duct
At which embryological stage does the thyroid gland reach it’s final position?
Week 7
Where are the platysma muscles located?
In the superficial fascia immediately deep to the skin on the anterior surface of the neck
Which group of muscles do the platysma muscles belong to and which nerve innervates them?
The muscles of facial expression Innervated by the facial nerve (CN7)
Which fascial compartment in the neck lies deep to the superficial fascia and encloses all other neck compartments?
Investing fascia
Which two muscles are enclosed within the investing (deep) fascia of the neck?
Trapezius Sternocleidomastoid
Which fascial compartment of the neck is the thyroid gland located in and what other structures are also contained within it?
Pretracheal fascia Also contains: Strap muscle Trachea Oesophagus Recurrent laryngeal nerves
Where is the retropharyngeal space located?
Between the pretracheal fascia and the prevertebral fascia
What are the attachments of the sternocleidomastoid?
Mastoid process of temporal bone Manubrium of sternum Clavicle
Which nerve supplies the sternocleidomastoid and the trapezius muscle?
CN X1 - the spinal accessory nerve
What is contained within the carotid sheath?
Common, then internal carotid artery Internal jugular vein Vagus nerve Deep cervical lymph nodes
Which arteries supply the thyroid gland?
Right & left superior and inferior thyroid artries
Which artery does the inferior thyroid artery branch from?
Subclavian artery
Which artery does the superior thyroid artery branch from?
External carotid artery
Which veins drain the thyroid gland?
Right & left superior, middle and inferior thyroid veins
Which vein does the superior and middle thyroid veins drain into?
Internal jugular
Which vein do the inferior thyroid veins drain into?
Brachiocephalic veins
What is the lymphatic drainage of the thyroid and parathyroid glands?
Superior and inferior deep cervical lymph nodes Pretracheal node Paratracheal nodes
Where does the right recurrent laryngeal nerve recur?
Under the subclavian artery
Where does the left recurrent laryngeal nerve recur?
Under the arch of the aorta
What are the names of the strap muscles?
Omohyoid Thyrohyoid Sternohyoid Sternothyroid
What structure is being indicated here?
Thyroid gland
Which muscle is being indicated here?
Thyrohyoid
Which muscle is being indicated here?
Sternothyroid
Which muscle is being indicated here?
Omohyoid
Which muscle is being indicated here?
Sternohyoid
