Lecture 27 - Endocrine Flashcards
Thyroid (Write it out)
Location:
Structure:
Blood Supply:
Blood Drainage:
Thyroid (Write it out)
Location:
- anterior, below thyroid cartilage
- inf larynx
Structure:
- 2 lobes connected via isthmus
Blood Supply:
- Superior thyroid artery
= branch of external carotid artery
- Inferior thyroid artery
= branch of the subclavian arteries
Blood Drainage:
- Superior and middle thyroid veins
= drain into internal jugular vein
- Inferior thyroid vein
= drains into the brachiocephalic vein
- collectively veins drain into the superior vena cava
Where do veins of the thyroid collectively drain>
Superior vena cava
Where does the the superior thyroid artery branch from
Superior thyroid artery = branch of the external carotid artery
Where does the inferior artery branch from>
Inferior thyroid artery = branch of the subclavian artery
Where do the superior and middle thyroid veins drain into?
The Superior and middle thyroid veins drain into the internal jugular vein
Where do the inferior thyroid veins drain into?
The inferior thyroid veins into the brachiocephalic vein
What cells make up the thyroid – type
Simple cuboidal cells called follicular cells make up the thyroid
What is stored in the cavity of follicular cells in the thyroid - describe
Colloid
- consists of thyroglobin
- contains molecules of tyrosine which get converted to thyroid hormone by iodine
What do follicular cells produce?
Follicular cells produce thyroglobulin
What are the names of T3 and T4?
T3 = Triiodothyronine
T4 = Thyroxine
What produces T3 and T4?
T thyrocytes produce T3 and T4
What stims release of T3 and T4?
TSH from the ant pit
Describe what happens when TSH is released
- TSH released from ant pit
- cuboidal cells take a bite of the colloid and ingests material
- inside the colloid there areT3 and T4 and enzymes help to get them out
What are the functions of thyroid hormones?
1) Increase rate of cellular metabolism and oxygen consumption
2) Helps maintain bp
3) Plays a role in tissue growth and development
What’s large parafollicular c cells or follicular cells
parafollicular cells
Where can you find parafollicular cells?q
C cells are btwn follicles or within
What do parafollicular C cells produce – function?
C cells produce - calcitonin
- lowers Ca ion [] by inhibiting the breakdown of bone and stim the excretion of Ca from the kidney
Parathyroid glands
Location:
Number:
Size:
Blood Supply/Drainage:
Parathyroid glands
Location: in posterior lateral lobes of thyroid
Number: 4
Size: 40 mg
Blood Supply/Drainage:
- same as thyroid
- blood from branches of superior and inf thyroid arteries
- drained by sup, mid, inf thyroid veins
What types of cells are found in the parathyroid, funciton
Chief cells:
- more common
- produce PTH
- PTH = increase Ca ion [] by targeting the breakdown of bone, enhancing Ca uptake by intestine, inhibiting urinary excretion of Ca
Oxyphil cells
- idk
What cells produces PTH
function
Chief cells in the parathyroid gland
PTH = increase Ca ion [] by targeting the breakdown of bone, enhancing Ca uptake by intestine, inhibiting urinary excretion of Ca
Adrenal Gland
Location:
Shape:
Blood supply:
Adrenal Gland
Location: superior to kidney
Shape: flattened pyramid
Blood supply:
- main = superior arteries form phrenic artery
- right/left/middle = from aorta
- inf = renal artery
Blood Drainage:
- Right gland -> inf vena cava
- Left gland -> left renal vein
What are the 3 zone of the adrenal cortex
- zona glomerulosa
- zone fasciculata
- zona reticularis
Describe the zona glomerulosa of the adrenal cortex
Zona Glomerulosa
- outer
- 15%
- spherical structures
- produce: mineral corticoids
= balance water and electrolytes in blood
- ex. aldosterone = mineralocorticoid that acts on the kidney to regulate sodium and potassium []
which zone of the adrenal gland produces mineralcorticoids?
The zona glomerulosa produces mineralocorticoids
Describe the zona fasciculata of the adrenal cortex
Zona fasciculata
- 78-80% of cortex
- cords or ropes
- cells contain lipid droplets
- stim by ACTH from ant pit to produce glucocorticoids
- glucocorticoids produces cortisol and corticosterone which influences the metabolism of carbs protein and fat
Where do glucocorticoids come from, what stims, what do?
Come from the zona reticularis
- stim by ACTH from ant pit to produce glucocorticoids
- glucocorticoids produces cortisol and corticosterone which influences the metabolism of carbs protein and fat
Describe the zona reticularis of the adrenal cortex
Zona reticularis
- 5-7% of cortex
- no organization
- makes some gonadotropin
- in females responsible for muscle mass, blood cell production, libedo
What cells are in the adrenal medualla - purpose
Adrenal medulla
= Chromaffin cells
- produce Epi and Ne
- are modified postganglionic neurons
- when stimulated by preganglionic sympathetic NS secrete caricotamides (Ne and Epi)
What are pancreatic islets and what do they contain
Pancreatic islets = Islets of Langerhans
- contains a,b,d cells
Describe the cells found in the pancreatic islets
Alpha cells
- produce glucagon
- stims liver to convert glycogen to glucose increasing blood glucose levels
- largest of the 3 cells
- often on periphery
Beta cells
- produce insulin
- smaller 70%
- scattered throughtout
- reduces blood glucose by enhancing the membrane transport into cells, inhibits conversion of glycogen to glucose in liver
Delta cells
- produce somatostatin
- small
- less than 5%
- inhibits the release of insulin and glucagon
- effect of quieting the digestive system
Where is the pineal gland located?
- hangs off the epithalamus, hangs from the roof of the 3rd ventricle
What cells are in the pineal gland?
- glial cells
Pinacocytes:
- produce and secrete melatonin
- controls circadian rhythm
- inhibits hypothalamic releasing hormones THF and TF
- biproduct becomes calcified = brain sand
