Endocrinology — the first-year Physiology chapter on hormones and the glands that make them

The nervous system sends its messages along nerves, fast, to one exact place. The body has a second way of sending messages. It releases chemicals into the blood, and the blood carries them everywhere. Those chemicals are hormones. This chapter is about them.

The NCH syllabus gives “Endocrinology” chapter nine of Physiology and Biochemistry (HomUG-PB). Endocrinology is the study of the endocrine glands and their hormones. An endocrine gland is a gland that releases its product straight into the blood, not through a tube. The sheet lists nine topics.

Topic one: the introduction, and the PNEI axis

The sheet says “Introduction of endocrinology and importance of PNEI axis”.

The sheet prints only the letters PNEI. They are commonly read as psycho-neuro-endocrine-immune. In plain words: mind, nerves, hormones and the body’s defence system. An “axis” here means a line of connection between systems. So the PNEI axis is the idea that these four are linked, and that a change in one can reach the others. Check the exact expansion your teachers use, and use theirs in the exam.

Notice the word the sheet chooses: “importance”. It does not only ask you to define the axis. It asks why it matters. For a homoeopathy student this is a place where the physiology paper looks toward the whole person, mind and body together. The Organon has its own language for that whole. Keep the two vocabularies labelled and apart in your answers.

Topic two: the control centre

“Hormones and hypothalamo-hypophyseal axis”.

First, what a hormone is, and the general ways hormones act. Then the axis. The hypothalamus is a part of the brain. You met it in chapter eight, the Central Nervous System. The hypophysis is another name for the pituitary gland. The two are joined, and together they control many other glands.

This is the topic to learn first and learn well. Much of the chapter hangs from it.

Topics three to nine: the glands, one by one

The sheet then walks through the glands:

• Pituitary gland
• Thyroid gland
• Parathyroid
• Endocrine functions of pancreas
• Adrenal cortex
• Adrenal medulla
• Endocrine functions of other organs

Two lines need a word.

“Endocrine functions of pancreas.” The pancreas does two jobs. One part makes digestive juice, which you will meet in chapter twelve. Another part releases hormones into the blood. This topic is about the second job only.

“Adrenal cortex” and “adrenal medulla.” The adrenal glands sit on top of the kidneys. Each has an outer layer, the cortex, and an inner core, the medulla. They are listed separately because they make different hormones and do different work.

The last line, “Endocrine functions of other organs”, is open. It reminds you that some organs you think of for other jobs also release hormones. Your textbook will say which ones.

A study method: one card per gland

For each gland, make a card with the same five headings:

1. Where it is.
2. The hormones it makes.
3. What each hormone does.
4. What controls its release.
5. What happens when there is too much or too little, as your textbook describes it.

Seven gland cards, plus one card for the hypothalamo-hypophyseal axis. That is the chapter.

How the chapter sits in the year

This is chapter nine. It follows the Central Nervous System, and the hypothalamus is the bridge between them. It leads into chapter ten, the Reproductive System, where the hormones of the testis and the menstrual cycle continue this story. It also connects to Psychology, which studies how mind and body affect each other.

What to take from it

1. Know what an endocrine gland is and what a hormone is.
2. Explain the PNEI axis and why the sheet calls it important.
3. Explain the hypothalamo-hypophyseal axis.
4. Make one card for each gland on the list.
5. Know the difference between the adrenal cortex and the adrenal medulla.

The sheet gives nine names. It does not list the hormones or what they do. Those come from your textbook and your teachers.

Where to go next on the platform

This piece sits in the first-year Physiology and Biochemistry room. “Central Nervous System — the first-year Physiology chapter on the brain and spinal cord at work” introduces the hypothalamus. “Reproductive System — the first-year Physiology chapter on how life continues” carries the hormone story forward. “Psychology in the First Year — the study of mind, for homoeopaths” is the other side of the PNEI idea.