Endocrine system Flashcards
Describe endocrine glands
Ductless glands
Secrete directly into the bloodstream
What is meant by exocrine glands?
Glands with ducts
Secrete directly into/onto an organ/tissue
E.g.
- salivary glands, sweat glands, pancreas (digestive juices)
What are the components of the endocrine system?
Pituitary Thyroid Parathyroids Pancreas Suprarenals (adrenals) Gonads - Ovaries and testes
Thymus and Pineal gland
Where is the pituitary located?
Between hypothalamus and pineal gland
Sits within sella turcica of sphenoid bone
Describe the other structures around the pituitary
Sella turcica is below the pituitary
Hypothalamus is above
Infundibulum is the pituitary stalk
What potential diseases are caused via the pituitary?
Secretions of pituitary include GH
Hypopituitarism
45.5 people out of 100,000
Most (61%) due to tumours
Hyperpituitarism - acromegaly/gigantism
Where is the thyroid gland located?
Extends from levels C5 – T1
Positioned anterolateral to the trachea and larynx
Infront of 2nd and 3rd tracheal rings
What is the structure of the thyroid gland?
L + R lobes joined by isthmus
- A pyramidal lobe is present in approximately 50% of the population, usually on the left side
What is the arterial supply to the thyroid gland?
External + Internal common carotid arteries
Superior + Inferior Thyroid arteries
Thyrocervical trunk
Subclavian artery
What is the venous drainage of the thyroid gland?
Superior, Middle and inferior thyroid veins
S + M drain into internal jugular veins
Inferior drains into braciocephalic vein
Which muscles cover the thyroid gland?
The thyroid gland is covered by the infra-hyoid strap muscles
Name the infra-hyoid muscles
Omohyoid (lateral)
Sternohyoid (medial)
Sternothyroid (deep)
What is the function of the thyroid gland?
Thyroid gland uses iodine from foods to form two2main hormones:
Triiodothyronine (T3)
Thyroxine (T4)
What are the parathyroid glands?
Two pairs embedded in the deep surface of the thyroid gland that produce parathyroid hormone
What is the function of parathyroid hormones?
Regulate body’s Ca2+ levels
What arteries supply the parathyroid gland?
Usually inferior thyroid arteries
Describe the venous drainage of the adrenal glands
Venous drainage is (usually) via one large vein into the IVC (on the right) and the renal vein (on the left)
Describe the arterial supply of the adrenal glands
Blood supply is from numerous small arteries from the renal artery, inferior phrenic artery and abdominal aorta
What is the pampiniform plexus?
Loose network of small veins found within male spermatic cord
What is the function of the pampiniform plexus?
Cool incoming arterial blood
Where does the pampiniform plexus terminate?
The veins terminate into IVC (right side) and renal vein (left side)
What forms the anterior neck triangle?
anterior border of scm/midline/ inferior border of mandible
What structures form the posterior triangle?
posterior border of scm/ anterior border of trapezius/ superior border of clavicle
What is the role of the accessory nerve?
Cranial nerve that supplies the sternocleidomastoid and trapezius muscles
