6.6 Hormones, homeostasis and reproduction Flashcards
What cells in the pancreas secrete insulin and glucagon to control blood glucose concentration?
Insulin is secreted by β-cells and glucagon is secreted by α-cells in the Islets of Langerhans in the pancreas.
What are the causes of Type I and Type II diabetes, and how are they treated?
Type I diabetes is caused by the body’s failure to produce insulin, treated with daily insulin injections. Type II diabetes results from insulin resistance, treated with diet, exercise, and sometimes medication.
What gland secretes thyroxin, and what are its effects on the body?
The thyroid gland secretes thyroxin, regulating metabolism and body temperature by increasing metabolic activities in tissues.
How does leptin act on the hypothalamus of the brain, and what is its role?
Leptin is secreted by adipose tissue, acts on the hypothalamus to inhibit appetite, regulating energy intake and fat stores.
Describe the role of melatonin in regulating circadian rhythms and its use in treating jet lag.
Melatonin, secreted by the pineal gland, controls circadian rhythms. It is high at night and low during the day, and its administration can alleviate jet lag by adjusting the body’s sleep cycle.
How does the gene on the Y chromosome affect the development of embryonic gonads?
A gene on the Y chromosome causes embryonic gonads to develop as testes, secreting testosterone, which influences male sexual development.
Outline the roles of testosterone in male development.
Testosterone causes prenatal development of male genitalia, sperm production, and development of male secondary sexual characteristics during puberty.
Describe the effects of estrogen and progesterone on female reproductive organ development.
Estrogen and progesterone cause prenatal development of female reproductive organs and female secondary sexual characteristics during puberty.
How is the menstrual cycle controlled by negative and positive feedback mechanisms?
The menstrual cycle is controlled by feedback mechanisms involving FSH, LH, estrogen, and progesterone, regulating ovulation and menstrual phases.
What roles do FSH, LH, estrogen, and progesterone play in the menstrual cycle?
FSH and LH stimulate follicle development and ovulation, while estrogen and progesterone regulate the uterine lining’s growth and shedding.
Outline the use of drugs in IVF to induce superovulation and establish a pregnancy.
In IVF, drugs are used to suspend normal hormone secretion, followed by artificial doses of hormones to induce superovulation and facilitate embryo implantation.
How did William Harvey’s investigation of sexual reproduction in deer challenge Aristotle’s theory?
Harvey’s dissections of female deer post-mating showed no small embryos, disputing Aristotle’s “seed and soil” theory by demonstrating early stages of sexual reproduction were not as previously thought.
Discuss the testing of leptin on patients with clinical obesity and reasons for its failure to control the disease.
Leptin testing on patients with clinical obesity aimed to reduce appetite and body weight. However, many obese individuals have developed leptin resistance, where their bodies do not effectively respond to leptin, making it less effective in controlling obesity.
What are key structures to identify in diagrams of the male and female reproductive systems?
In male diagrams, identify the testes, epididymis, sperm duct, seminal vesicles, prostate gland, urethra, and penis. In female diagrams, identify the ovaries, fallopian tubes, uterus, cervix, vagina, and vulva.
How do FSH and LH influence the menstrual cycle in females?
FSH (Follicle-Stimulating Hormone) stimulates the growth of ovarian follicles in the ovary before the release of an egg, while LH (Luteinizing Hormone) triggers ovulation and development of the corpus luteum.
