The thyroid gland is the largest endocrine gland located in the neck below the larynx. It is butterfly or H-shaped, consisting of two lobes connected by an isthmus across the trachea. The thyroid contains follicles composed of follicular cells that secrete the hormones thyroxine (T4) and triiodothyronine (T3). Parafollicular cells located between follicles secrete calcitonin, which regulates calcium levels. The thyroid's primary function is to produce thyroid hormones that regulate basal metabolic rate, skeletal growth, body temperature, muscle strength, and other vital body functions.

1. THYROID GLAND STRUCTURE AND
FUNCTION
2018-19
SUBMITTED BY- NAGENDRA SAHU
GUIDED BY- DR. RASHMI SRIVASTAVA
(DEPARTMENT OF ZOOLOGY)
DR.HARI SINGH GOUR UNIVERSITY
SAGAR(M.P)
GG

2. CONTENTS
1.Position of thyroid gland
2.Weight
3.Structure
4.Microanatomy
.Follicles
.Follicular cells
.Para follicular cells
5.Histology
6.Function

3. Introduction
 Largest endocrine gland in the body
 First described by Whortonin in 1659
 It descriptive name thyroid

4. Position
• It is located in neck region
• It is located immediately below larynx
•Larynx on each side of and anterior to trachea
oWeight.15 -20 gm in a adult
•It is slightly large during pregnancy in women
•It is located between the C5-T1 vertebrae

5. Structure
 Thyroid is H/butterfly shaped
 It consists of two lobes
 Below the larynx
 2 lobe are connected across the ventral
surface of trachea with a narrow bridge called
isthmus
 The thyroid is closely attached by the
pre-tracheal fascia

7. Microanatomy
• 3 primary features of thyroid
. Follicles-thyroid follicles are small spherical
.groups of cell (0.02-0.9mm) in diameter
.play main role in thyroid function
.Follicular cells –follicle is surrounded by a single
layer of follicular cells
. Follicular cell stimulate by TSH
.Secret T3 and T4
.It feel up glycoprotein

9. Para follicular cells
• Scattered among follicular cells
• It spaces b/w the spherical follicles are
another type of thyroid cell is called Para
follicular cells
• Cells secrets calcitonin and are also called C
cell.

11. Function
• The primary function of thyroid gland is the
production of Iodine containing thyroid
hormones , triiodothyronin (T3) and thyroxine
(T4) and peptide hormone calcitonin
• BMR-basal metabolic rate
- Hyperthyroidism
- Hypothyroidism
•

12. • More effect on skeletal growth
• Less effect on soft tissue
• Regulation of calcium level-
• Thyrocalcitonin hormone play the very very
important role in the regulation of the calcium
level of the body
• Thyroid hormones regulate vital body functions,
including
• 1 Body weight 2. body temperature
3 . Muscle strength 4.menstrual cycle

13. REFRENCES
1. CLASS NOTES.
2. MEDICAL PHYSIOLOGY. Viz GUYTON AND HALL.
3. WIKIPEIDA.
4. YOUTUBE.