13. Endocrine glands (anatomy) Flashcards
Where does the pituitary gland sit?
In the sella turcica of the sphenoid bone
The sella turcica has bone anteriorly and posteriorly BUT not to the sides - so in a pituitary adenoma, the growth would be laterally outwards
What is the infundibulum?
This is the pituitary stalk - the connection between the hypothalamus and the posterior pituitary
How do the anterior and posterior lobes of the pituitary gland differ from each other?
The posterior lobe is a continuation of the hypothalamus - composed of neurones and is not a true endocrine gland
The anterior lobe is pinker in colour and is made up of endocrine secretory cells rather than neuronal cells
What hormones are released from the anterior lobe of the pituitary gland?
Adrenocroticotrophic hormone (ACTH) Thyroid-stimulating hormone (TSH) Luteinising hormone (LH) Follicle stimulating hormone (FSH) Prolactin (PRL) Growth hormone (GH) Melanocyte-stimulating hormone (MSH)
What hormones are released from the posterior lobe of the pituitary gland?
Anti-diuretic hormone (ADH)
Ocytocin
Where do secretions of the pituitary gland drain to?
The hypothalamo-hypophyseal portal system
Where are the adrenal glands located?
On top of the kidneys at the posterior wall of the abdomen
They are submerged in perineal fat
What are the different parts of the adrenal glands and what do they secrete?
Adrenal cortex (outer) - aldosterone and cortisol Adrenal medulla (inner) - adrenalin and noradrenalin
Where does the thyroid gland lie?
Lies at the level of C5-T1 over the cricoid cartilage
Anterior to the trachea and oesophagus
Where are the parathyroid glands located and how many are there?
What is their function?
These are just posterior to the thyroid glands
Generally have four thyroid glands but can have more
Parathyroid glands secrete the parathyroid hormone (PTH) which acts to secrete and increase the levels of blood calcium
What are the two major functions of the pancreas?
Exocrine functions - release of digestive enzymes
Endocrine functions - synthesis and release of insulin and glucose
What is the blood supply to the pancreas?
From the coeliac trunk (splenic artery - main branch is the transverse pancreatic branch) and the SMA - inferior pancreatoduodenal artery
What is the vascular connection between the hypothalamus and the anterior pituitary gland?
Superior hypophyseal artery from hypothalamus to infundibulum - blood can travel between the two
What is the superior hypophyseal artery a branch of?
Internal carotid artery
Where does blood from the anterior pituitary gland drain to?
Drains to the hypopyseal portal vein
What is the vascular connection between the anterior pituitary gland and the posterior pituitary gland?
Secondary capillary plexus
What fibres synapse at the adrenal medulla?
Preganglionic sympathetic fibres
What are the three arteries to the adrenal gland and where do these branch from?
Superior suprarenal artery - from the inferior phrenic artery
Middle suprarenal artery - from the abdominal aorta
Inferior suprarenal artery - from the renal artery
Where do the suprarenal veins drain to?
Left - left renal vein
Right - IVC
What are the lobes of the thyroid gland?
Left and right lobe - some people will also have a pyramidal lobe inbetween the left and right lobes
What is the blood supply to the thyroid gland?
Superior thyroid artery and inferior thyroid artery
Where does the inferior thyroid artery branch from?
Subclavian artery - thyrocervical trunk
Where does blood from the thyroid gland drain to?
Superior, middle and inferior thyroid veins
Where do the superior, middle and inferior thyroid veins drain to?
Superior and middle - internal jugular vein
Inferior - brachiocephalic
Which nerve runs anterior to the thyroid gland?
Recurrent laryngeal nerve
Where does the head of the pancreas sit?
In the curve of the duodenum
Where does the tail of the pancreas extend to?
Extends to the spleen
What is the most common cause of acute pancreatitis?
Gallstones in the sphincter of Oddi causing a build up of bile - results in acute inflammation - digestion of the pancreas
What is a common behavioural cause of acute pancreatitis?
Alcoholism
