Essential Idea:
Hormones are used when
signals need to be widely distributed
Understandings:
- Insulin and glucagon are secreted by β and α cells of the pancreas respectively to control blood glucose concentration
- Thyroxin is secreted by the thyroid gland to regulate the metabolic rate and help control body temperature
- Leptin is secreted by cells in adipose tissue and act on the hypothalamus of the brain to inhibit appetite
- Melatonin is secreted by the pineal gland to control circadian rhythms
- A gene on the Y chromosome causes embryonic gonads to develop as testes and secrete testosterone
- Testosterone causes pre-natal development of male genitalia and both sperm production and development of male secondary sexual characteristics during puberty
- Estrogen and progesterone cause pre-natal development of female reproductive organs and female secondary sexual characteristics during puberty
- The menstrual cycle is controlled by negative and positive feedback mechanisms involving ovarian and pituitary hormones
Applications:
- Causes and treatment of Type I and Type II diabetes
- Testing of leptin on patients with clinical obesity and reasons for the failure to control the disease
- Causes of jet lag and use of melatonin to alleviate it
- The use in IVF of drugs to suspend the normal secretion of hormones, followed by the use of artificial doses of hormones to induce superovulation and establish a pregnancy
- William Harvey’s investigation of sexual reproduction in deer
Skills:
- Annotate diagrams of the male and female reproductive system to show names of structures and their functions