Thyroid gland and hormonessssssssssssssss

...

1. Thyroid Gland & hormones
By Dr Atharva Shirodkar

2. Location of Thyroid gland

3. Microscopic Appearance of the
Thyroid Gland
Figure 76-1; Guyton & Hall

4. Thyroid Hormones
•T
3 (triiodothyronine)
•T
4 (Thyroxine)
•Calcitonin

5. Thyroid Hormone Synthesis
& Secretion
Figure 76-2; Guyton & Hall

7. Metabolism of Thyroxine by Deiodination
in Peripheral Tissues
OHO
I I
C
HNH2
COOHC
H
H
I I
TT
44
OHO
I I
C
HNH2
COOHC
HH
I
T3T3
OHO
I I
C
HNH2
COOHC
HH
I
RTRT
33
5’/3’-deiodinase5’/3’-deiodinase
5/3-deiodinase5/3-deiodinase

8. 80 ug/day
31 ug/day
38 ug/day
T
4
T
3
RT
3
Secreted by thyroid
Deiodination of T
4
in
peripheral tissues
Thyroid Hormone Production

9. Plasma protein-Plasma protein-
bound Tbound T
44
ThyroidThyroid
Free TFree T
44 in in
plasmaplasma
Tissue TTissue T
44
Anterior Anterior
pituitarypituitary
Interrelationships Between Free &
Bound T
4
BiologicalBiological
effectseffects
TSH

11. Actions of Thyroid Hormones
Figure 76-5;
Guyton & Hall

12. Metabolic Effects of Thyroid Hormones
Parameter ↓ T
3
, T
4
↑ T
3
, T
4
Basal metabolic rate ↓ ↑
Carbohydrate metabolism ↓ Gluconeogenesis ↑ Gluconeogenesis
↓ Glycogenolysis ↑ Glycogenolysis
Normal serum [glucose] Normal serum [glucose]

Protein metabolism ↓ Synthesis ↑ Synthesis
↓ Proteolysis ↑ Proteolysis
Muscle wasting
Lipid metabolism ↓ Lipogenesis ↑ Lipogenesis
↓ Lipolysis ↑ Lipolysis
↑ Serum [cholesterol] ↓ Serum [cholesterol]
Thermogenesis ↓ ↑

Table 48-1, Boron & Boulpaep

13. Hypothalamohypophyseal-Thyroid Axis
HypothalamusHypothalamus
Pituitary glandPituitary gland
ThyroidThyroid
TT
33, T, T
44
TRH TRH
TSHTSH
__
__
+
+

14. Appearance of thyroid follicles in different levels
of activity.

15. Pathophysiology of Thyroid Hormones
(hyperthyroidism)
• Graves’ disease
(Hypothyrodism)
•Hashimoto’s Thyroiditis
• Myxedema
• Cretinism

16. Hypothalamo-hypophyseal-Thyroid Axis in Graves’
Disease

17. Grave’s Disease

18. Thyroid disorders in a nutshell
Hyperthyroidism
Bulging eyes, facial flushing, Enlarged thyroid, Tachycardia,
Increased Systolic BP, Breast Enlargement, Weight loss, Muscle
wasting

19. Fig. 111.11: A child with cretinism. Note the potbelly and
protrusion of tongue of the child.

20. Treatment of Thyroid Pathologies
•Hyperthyroidism- surgery, Radio-iodine
•Hypothyroidism- Levothyroxine

21. Pineal Gland

23. Thymus Gland