23 - Thyroid Flashcards
1
Q
When does the thyroid develop
A
At 24 days
- 2 pouches and 1 groove
2
Q
What is a pouch
A
Endodermal outpouching of pharynx
3
Q
Pouch 3
A
Inferior parathyroid and thymus
4
Q
Pouch 4
A
Superior parathyroid and ultimobranchial body
5
Q
What cells are in the ultimobranchial body
A
C-cells
6
Q
what does a non-duct closure cause
A
Thyroglossal cyst
7
Q
What are thyroid follicles cells
A
Cuboidal
Columnar when active
8
Q
How many follicles are there per thyroid lobule
A
20-40
9
Q
What do follicle cells produce
A
Thyroid hormones
10
Q
T3
A
Triiodothyronine
11
Q
T4
A
Thyroxine
12
Q
Mechanism of thyroid release + negative feedback
A
Hypothalamus secretes TRH
–> Anterior pituitary secretes TSH –> Thyroid gland produces T3 and T4
Neg feedback - too much T3 and T4 –> TRH and TSH are inhibited
