• 12 parts
  • Checked September 2026

Thyroid Gland Diagram

The thyroid from the front and from behind, then its tissue and the parathyroid's, cell by cell.

Thyroid Gland Diagram

Name Date

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1 2 3 4 5 6 7 8 9 10 11 12
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Write the name of each numbered part.Answer key

  1. Right lobe
  2. Left lobe
  3. Isthmus
  4. Larynx
  5. Trachea
  6. Parathyroid glands
  7. Thyroid follicle
  8. Colloid
  9. Follicular cells
  10. Parafollicular cells (C cells)
  11. Chief cells
  12. Oxyphil cells

Drawn for this site on 2026-09-30 from plain geometry. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Zoom out: the endocrine glands on the body

All 12 parts on the diagram

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The gland in the neck 6

  1. Right lobe From the front it is on your left. In the view from behind, the sides swap.
  2. Left lobe From the front it is on your right. In the view from behind, the sides swap.
  3. Isthmus It crosses the front of the trachea.
  4. Larynx The thyroid gland sits just below it.
  5. Trachea Its rings show below the gland. From behind, only the ends of the rings show.
  6. Parathyroid glands Most people have four. They make parathyroid hormone, which raises the level of calcium in the blood.

Under the microscope 6

  1. Thyroid follicle Thyroid tissue is made mostly of follicles. The thyroid hormones are made there.
  2. Colloid The thyroid hormones are made in it. They are kept there until needed.
  3. Follicular cells They take iodide from the blood for making the thyroid hormones.
  4. Parafollicular cells (C cells) They make calcitonin.
  5. Chief cells They make parathyroid hormone.
  6. Oxyphil cells Their function is not clear.

How this list was compiled: Every name and detail checked on 2026-09-30 against OpenStax Anatomy and Physiology 2e, sections 17.4 The Thyroid Gland (position below the larynx and in front of the trachea, isthmus, left and right lobes, follicles, colloid, follicle cells, parafollicular cells and calcitonin), https://openstax.org/books/anatomy-and-physiology-2e/pages/17-4-the-thyroid-gland, and 17.5 The Parathyroid Glands (four glands on the posterior surface, chief cells, oxyphil cells, parathyroid hormone), https://openstax.org/books/anatomy-and-physiology-2e/pages/17-5-the-parathyroid-glands, and against Wikipedia, Thyroid, Parathyroid gland and Parafollicular cell, text only. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced and no micrograph copied. Licence: own work

How it works

The thyroid gland lies in front of the trachea, just below the larynx. The first drawing shows it from the front and from behind; the next two show thyroid tissue and parathyroid tissue as under a microscope.

Read the full guide

From the neck down to the cells

Numbers 1 to 6 are on the gland in the neck: the two lobes, the isthmus that joins them, the larynx above, the trachea behind, and the four parathyroid glands on the back of the lobes. Numbers 7 to 10 are in thyroid tissue: a follicle, its colloid, the follicular cells round it and the parafollicular cells between follicles. Numbers 11 and 12 are the two cell types of a parathyroid gland.

  • From the front, the right lobe is on your left. From behind, the sides swap.
  • Follicular cells form the wall of a follicle; parafollicular cells lie between follicles.

Questions and answers

What are the cells of the thyroid gland?

Follicular cells form the wall of each follicle and make the thyroid hormones T3 and T4 in the colloid they surround. Parafollicular cells, also called C cells, lie between the follicles and make calcitonin.

What are the cells of the parathyroid gland?

Chief cells are the main working cells: they make parathyroid hormone, which raises the level of calcium in the blood. Oxyphil cells are the second type, and their function is not clear.

What is colloid in the thyroid?

Colloid is the sticky fluid that fills the middle of each thyroid follicle. The thyroid hormones are made in it, on a protein called thyroglobulin, and stay there until the gland is signaled to release them.

Where are the parathyroid glands?

Usually on the back of the thyroid gland, set into its two lobes. Most people have four: two on each side, one above the other.

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