It includes anatomical location, vascular supply, lymphatic drainage , embryonic development and their hormone synthesis, release and regulation.

1. Jinnah College
of Nursing
Anatomy and physiology ofAnatomy and physiology of
Thyroid &Thyroid &
ParathyroidParathyroid
glandgland
Subject Faculty : Mr. Sultan
Students : Maryam Noor & Zerish

3. The thyroid gland is a butterfly shaped endocrine organ
found in the neck.
It is responsible for regulating the body’s metabolic rate
via hormones it produces.

4. Anterolateral Posterolateral Posteromedial
•Sternothyroid
•Sternohyoid
•Common carotid artery
•Internal jugular vein
•Vagus nerve
•Larynx
•Trachea
•Pharynx
•Oesophagus
•External laryngeal nerve

5. Anatomical location

7. Superior thyroid artery
• It is the first branch of the external carotid
artery.
• After arising, the artery descends toward the
thyroid gland.
• It supplies the superior and anterior portions
of the gland.

8. Inferior thyroid artery
• It arises from the thyrocervical trunk (which in turn
is a branch of the subclavian artery).
• The artery travels superomedially to reach the
inferior pole of the thyroid.
• It tends to supply the posteroinferior aspect of the
gland.

10. The thyroid originates from two main structures:
the primitive pharynx and the neural crest.
•The lateral thyroid develops from neural crest cells.
•The median thyroid, which forms the bulk of the
gland, arises from the primitive pharynx.

11. Lymphatic drainage
The lymphatic drainage of the thyroid is
multidirectional and extensive.
• It drains initially into peri-thyroid nodes, and from
there into prelaryngeal, pretracheal and
paratracheal nodes.
• Laterally, the gland drains into the superior and
inferior deep cervical nodes.

12. Histology
Structural unit is follicle.
Follicle consists of layer of
cuboidal epithelium (follicles)
Enclosing cavity called follicular
cavity.
Cavity is filled with gel like
viscous iodine rich material
colloid.
Interfollicular spaces are filled
by connective tissue adipose
tissue and blood vessels.

13. Histology

14. Physiology
• The thyroid gland is the regulator of metabolism.
• T3 and T4 typically act via nuclear receptors in target
tissues and initiate a variety of metabolic pathways.
Metabolic processes increased by thyroid hormones include:
• Basal Metabolic Rate
• Gluconeogenesis
• Glycogenolysis
• Protein synthesis
• Lipogenesis
• Thermogenesis

15. Hormone synthesis

16. Thyroid hormones cont..

17. Thyroid Hormone Regulation

18. Calcitonin
• It lowers the calcium level.
• Blood calcium C cells Calcitonin
• Calcitonin Negative feedback PTH

20. Anatomy of parathyroid
Shape:
 They are flattened and oval in shape,
situated external to the gland itself, but
within its sheath.
Anatomical location:
 They are located on the posterior, medial
aspect of each lobe of the thyroid gland.

21. Anatomy Cont....
Size and weight:
– Size of a grain of rice.
– 30 milligrams weighs approximately.
– 3-4 millimeters in diameter.
– The majority of people have four parathyroid gland

24. Vascular supply
Blood supply:
– Through superior and inferior thyroid arteries.
Venous return:
– The parathyroid veins drain into the thyroid plexus of
veins.
Lymphatic drainage:
– Into the deep cervical lymph nodes and paratracheal
lymph nodes.

25. Nerve supply
• Nerve supply derived from thyroid branches of
the cervical (sympathetic) ganglia.
• These nerves are vasomotor, not secretomotor –
endocrine secretion of parathyroid hormone is
controlled hormonally.

26. Physiology

27. Functions of PTH
• Suppression of calcium loss in urine.
• Stimulate loss of phosphate ions in urine
• Mobilization of calcium from bone.
• Enhancing absorption of calcium from the small
intestine.
• Activation of Vitamin DActivation of Vitamin D

28. Parathyroid hormone (PTH)

32. PTH vs. Calcitonin

33. Calcium

34. References:
• https://www.ncbi.nlm.nih.gov/books/NB
K519566/
• https://teachmephysiology.com/endocri
ne-system/paratkhyroid-
glands/parathyroid-gland/