APE 7: The endocrine system Flashcards
What’s another name for the pituitary gland?
The hypophysis
Describe the structure and position of the pituitary gland
The pituitary gland is a pea-sized structure, suspended from the underside of the brain by the pituitary stalk (the infundibulum). It sits in the hypophyseal fossa on a small depression in the sphenoid bone known as the sella turcica
What’s the name of the reflection of the dura mater through which the infundibulum passes?
The diaphragma sellae
What is anterior to the pituitary gland?(The gland can be accessed via this structure in surgery)
The sphenoid sinus
What 4 things are found posterior to the pituitary gland?
The posterior intercavernous sinus, the dorsum sellae, the basilar artery and the pons
What sinus is lateral to the pituitary gland?
The cavernous sinus
What are the names of the 2 lobes of the pituitary gland?
The anterior lobe is called the adenohypophysis. The posterior lobe is called the neurohypophysis.
What are the names of the 3 parts of the anterior lobe?
Pars anterior, Pars intermediate and Pars tuberalis
What is pars anterior responsible for?
Pars anterior is responsible for hormone secretion.
Via what vessels does the hypothalamus communicate with the pituitary gland to control hormone release?
The hypophyseal portal vessels
What is the importance of the hypophyseal portal vessels?
These vessels ensure that the hypothalamic hormones remain concentrated, rather than being diluted in the systemic circulation
What tissue type does the posterior lobe of the pituitary consist of?
Nervous tissue
Upon stimulation, which 2 hormones does the posterior pituitary secrete?
ADH and oxytocin
What is the function of ADH?
Regulation of blood osmolarity
What is the function of oxytocin?
Parturition and milk secretion
How many bones make up the cranium?
There are 8 bones
What does the sphenoid bone consist of?
A body, paired greater wings and lesser wings, and 2 pterygoid processes
What sinuses does the body of the sphenoid bone contain?
The sphenoid sinuses
With what bone does the sphenoid bone articulate with anteriorly and where do the sphenoid sinuses open up into ?
The sphenoid body articulates anteriorly with the ethmoid bone. Here, the sphenoid sinuses open into the nasal cavity
What structure is found on the superior surface of the sphenoid body?
The sella turcica, where the pituitary gland sits
What is the schismatic groove in the superior surface of the sphenoid body?
A sulcus formed by the optic chiasm (where the optic nerves partially cross).
In what direction do the greater wings extend from the sphenoid body?
A lateral, superior and posterior direction.
What 3 parts of the facial skeleton do the greater wings of the sphenoid bone contribute to?
The floor of the middle cranial fossa.
The lateral wall of the skull.
The posterolateral wall of the orbit.
What are the names of the 3 foramina present on each of the greater wings?
The foramen rotundum, foramen vale and foramen spinosum.
In what direction do the lesser wings arise from the sphenoid body?
A superolateral direction
What border of the optic canal does each lesser wing form?
The lateral border of the optic canal
The pterygoid processes descend inferiorly from what point of the sphenoid bone?
The pterygoid process descends inferiorly from the points of junction between the sphenoid body and the greater wings
What are the names of the 2 parts of the pterygoid processes?
The medial pterygoid plate and the lateral pterygoid plate
Where and at what spinal level does the hyoid bone lie?
The hyoid bone lies at ~C3, at the base of the mandible in the anterior neck
What is the hyoid bone composed of?
A body, 2 greater horns and 2 lesser horns
What are the four infra hyoid muscles located inferiorly to the hyoid bone?
The omohyoid, sternohyoid, sternothyroid and thyrohyoid muscles
Between what vertebral levels does the thyroid gland span?
C5 to T1
What’s the name of the part that connects the 2 lobes of the thyroid gland to form a butterfly shape?
The isthmus
What cartilage does the thyroid gland wrap around?
The cricoid cartilage (and the superior tracheal rings)
What can be found immediately posterolaterally to the thyroid gland?
The carotid sheath
What borders the anterior triangle of the neck?
The imaginary midline (sagittal line) is the medial border.
The inferior border of the mandible is the superior border.
The anterior border of the SCM is the lateral border of the triangle
What are the 4 supra hyoid muscles in the neck?
The stylohyoid, digastric, mylohyoid and geniohyloid muscles
What are the borders of the posterior triangle of the neck?
Anterior border- posterior border of SCM
Posterior border- Anterior border of the trapezius muscle
Inferior border- The middle 1/3rd of the clavicle
What covers the posterior triangle of the neck?
Investing fascia
Where are the adrenal glands found?
Immediately superior to the kidneys on the posterior abdominal wall
What shapes are the suprarenal glands?
The right gland is triangular. The left gland is crescent-shaped
What arteries supply the adrenal glands?
Superior, middle and inferior adrenal arteries
What venous drainage is there for the adrenal glands?
The left adrenal vein drains into the renal vein, while the right adrenal vein drains straight into the inferior vena cava
Where does the pancreas lie?
The pancreas lies across the posterior part of the abdomen
Where does blood supply to the pancreas come from?
The splenic artery supplies the pancreas with blood, having come from the coeliac trunk of the abdominal aorta
What vertebral level is the pancreas at?
The head is at L2, while the tail is at T12
What regions of the abdomen is the pancreas in?
The epigastric and left hypochondrium regions, deep in the upper abdomen
Where’s the stomach in relation to the pancreas?
The stomach lies anterior to the pancreas and they’re separated by the lesser sac
Where’s the duodenum in relation to the pancreas?
The ‘C-shaped’ duodenum curves around and outlines the head of the pancreas, starting anteriorly and curving round laterally to the right of the pancreatic head
Where’s the spleen in relation to the pancreas?
The spleen is located posterolaterally to the pancreas and connected to the tail of the pancreas by the lienorenal ligament, formed from peritoneum
What are the 5 parts of the pancreas?
The head The uncinate process The neck The body The tail
What’s the uncinate process?
A projection arising from the lower part of the head of the pancreas, which extends medially to lie beneath the body of the pancreas
