Sex hormones, gut hormones and a map of the glands
The gonads, the ovaries and the testes, make gametes, and they also make sex hormones. These are steroids that shape the sex organs and the secondary sex features. Androgens, such as testosterone and androsterone, are made by the interstitial cells of the testis. They make the prostate gland and the seminal vesicles grow and bring about the male features. Oestrogen is made by the follicle, the corpus luteum and the placenta; it brings about the female features and regulates the menstrual cycle. Progesterone is made by the corpus luteum and the placenta; it prepares the wall of the uterus to receive the embryo and brings about changes in the mammary glands during pregnancy. Relaxin, made in the placenta and uterus, loosens the pubic symphysis at the end of pregnancy so delivery is easier. The lining of the digestive canal also makes hormones. Gastrin comes from the stomach wall and returns by the blood to the stomach to make it release gastric juice. Secretin and cholecystokinin come from the lining of the intestine and travel in the blood to the pancreas, to make it release its juice. Cholecystokinin also makes the gall bladder contract and release bile into the duodenum. Put together, the glands of this chapter form a map: each gland has its own hormones and its own jobs, and many of them are switched on by another hormone or by a level in the blood.
| Hormone | Made in | Job |
|---|---|---|
| Testosterone and other androgens | interstitial cells of the testis | growth of the prostate and seminal vesicles; male features |
| Oestrogen | follicle, corpus luteum, placenta | female features; regulates the menstrual cycle |
| Progesterone | corpus luteum, placenta | prepares the uterus for the embryo; mammary changes in pregnancy |
| Relaxin | placenta and uterus | loosens the pubic symphysis late in pregnancy |
| Gastrin | stomach wall | gastric juice |
| Secretin and cholecystokinin | lining of the intestine | pancreatic juice; cholecystokinin also makes the gall bladder release bile |
| Gland | Hormones | One job |
|---|---|---|
| Pituitary | growth hormone, TSH, ACTH, FSH, LH, prolactin, ADH, oxytocin | controls growth and other glands |
| Thyroid | thyroxine, calcitonin | metabolic rate; lowers blood calcium |
| Parathyroids | parathormone | raises blood calcium |
| Adrenal cortex | cortisone, aldosterone | carbohydrate and mineral balance |
| Adrenal medulla | adrenaline, noradrenaline | emergency response |
| Pancreas (islets) | insulin, glucagon | steady blood glucose |
| Gonads | androgens, oestrogen, progesterone | sex features and reproduction |
| Stomach and intestine lining | gastrin, secretin, cholecystokinin | release of digestive juices |
Make gland cards, with a grown-up. On eight small cards write one gland on the front and its hormones and one job on the back, using the map in this lesson. Shuffle them and have someone read the front while you answer from memory, then swap. Sort the cards into three piles: glands switched on by a pituitary hormone, glands that respond to a level in the blood, and glands switched on by nerves.