Lecture 27 - Endocrine

Question 1

Thyroid (Write it out)
Location:
Structure:
Blood Supply:
Blood Drainage:

Answer 1

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

Question 2

Where do veins of the thyroid collectively drain>

Answer 2

Superior vena cava

Question 3

Where does the the superior thyroid artery branch from

Answer 3

Superior thyroid artery = branch of the external carotid artery

Question 4

Where does the inferior artery branch from>

Answer 4

Inferior thyroid artery = branch of the subclavian artery

Question 5

Where do the superior and middle thyroid veins drain into?

Answer 5

The Superior and middle thyroid veins drain into the internal jugular vein

Question 6

Where do the inferior thyroid veins drain into?

Answer 6

The inferior thyroid veins into the brachiocephalic vein

Question 7

What cells make up the thyroid – type

Answer 7

Simple cuboidal cells called follicular cells make up the thyroid

Question 8

What is stored in the cavity of follicular cells in the thyroid - describe

Answer 8

Colloid
- consists of thyroglobin
- contains molecules of tyrosine which get converted to thyroid hormone by iodine

Question 9

What do follicular cells produce?

Answer 9

Follicular cells produce thyroglobulin

Question 10

What are the names of T3 and T4?

Answer 10

T3 = Triiodothyronine
T4 = Thyroxine

Question 11

What produces T3 and T4?

Answer 11

T thyrocytes produce T3 and T4

Question 12

What stims release of T3 and T4?

Answer 12

TSH from the ant pit

Question 13

Describe what happens when TSH is released

Answer 13

• 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

Question 14

What are the functions of thyroid hormones?

Answer 14

1) Increase rate of cellular metabolism and oxygen consumption
2) Helps maintain bp
3) Plays a role in tissue growth and development

Question 15

What’s large parafollicular c cells or follicular cells

Answer 15

parafollicular cells

Question 16

Where can you find parafollicular cells?q

Answer 16

C cells are btwn follicles or within

Question 17

What do parafollicular C cells produce – function?

Answer 17

C cells produce - calcitonin
- lowers Ca ion [] by inhibiting the breakdown of bone and stim the excretion of Ca from the kidney

Question 18

Parathyroid glands
Location:
Number:
Size:
Blood Supply/Drainage:

Answer 18

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

Question 19

What types of cells are found in the parathyroid, funciton

Answer 19

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

Question 20

What cells produces PTH
function

Answer 20

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

Question 21

Adrenal Gland
Location:
Shape:
Blood supply:

Answer 21

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

Question 22

What are the 3 zone of the adrenal cortex

Answer 22

• zona glomerulosa
• zone fasciculata
• zona reticularis

Question 23

Describe the zona glomerulosa of the adrenal cortex

Answer 23

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 []

Question 24

which zone of the adrenal gland produces mineralcorticoids?

Answer 24

The zona glomerulosa produces mineralocorticoids

Question 25

Describe the zona fasciculata of the adrenal cortex

Answer 25

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

Question 26

Where do glucocorticoids come from, what stims, what do?

Answer 26

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

Question 27

Describe the zona reticularis of the adrenal cortex

Answer 27

Zona reticularis
- 5-7% of cortex
- no organization
- makes some gonadotropin
- in females responsible for muscle mass, blood cell production, libedo

Question 28

What cells are in the adrenal medualla - purpose

Answer 28

Adrenal medulla
= Chromaffin cells
- produce Epi and Ne
- are modified postganglionic neurons
- when stimulated by preganglionic sympathetic NS secrete caricotamides (Ne and Epi)

Question 29

What are pancreatic islets and what do they contain

Answer 29

Pancreatic islets = Islets of Langerhans
- contains a,b,d cells

Question 30

Describe the cells found in the pancreatic islets

Answer 30

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

Question 31

Where is the pineal gland located?

Answer 31

• hangs off the epithalamus, hangs from the roof of the 3rd ventricle

Question 32

What cells are in the pineal gland?

Answer 32

• glial cells

Pinacocytes:
- produce and secrete melatonin
- controls circadian rhythm
- inhibits hypothalamic releasing hormones THF and TF
- biproduct becomes calcified = brain sand