What are the different types of hormones around our body, and how does it maintain human homeostasis?
→ How hormones influence our body behaviour
→The mechanisms of menstrual cycle
→ In- Vitro Fertilisation
Homeostasis and Hormones
Hormones: substances that stimulate target cells via the blood
→ Released directly into the blood plasma from endocrine glands
→ Produces slow, long-lasting & widespread responses
→ Hormones come from the Endocrine system: contains several different glands. Each gland secretes different hormones directly into the bloodstream.
- signal type:
- speed of signal: relatively
slow, travels in the bloodstream
- duration of signal:
- signal type:
electrical (action potential)
- speed of signal: reach the target cells
- duration of signal:
Pituitary gland - in the brain
→secretes several hormones (reproductive hormones) => Follicle-stimulating hormone (FSH) & Luteinizing hormone (LH) both for menstrual cycle
Pineal Glands- in brain
→ Secretes Melatonin to control circadian rhythm
→ Over a prolonged period, melatonin secretion becomes used to the onset of darkness and the approach of day, regulating the sleeping schedule of humans
Thyroid gland- located in the front of the neck below the larynx
→ Releases a hormone called thyroxin => helps to regulate the basal metabolic rate.
→Thyroxin is released in response to a decrease in body temperature in order to stimulate heat production
→Control blood glucose concentration through: alpha cells => glucagon AND beta cells => insulin
→Insulin is released from beta cells of the pancreas and cause a decrease in blood glucose concentration
→Glucagon is released from alpha cells of the pancreas and cause an increase in blood glucose concentration
Adrenal glands- located above each kidney
→Release several hormones including adrenaline for flight or fight response
Adipose Cells- From adipose tissues
→ Creates leptin to regulate fat stores within the body by suppressing appetite
→Overeating causes more adipose cells to formed and hence more leptin is produced, suppressing further appetite
→Produce the female reproductive hormones => estrogen & progesterone to aid menstrual cycle and secondary characteristics eg. wider hips
→Produce the male reproductive hormone => testosterone which develops secondary characteristics eg. hair
→Follicle Stimulating Hormone and Luteinizing Hormone are produced by the anterior lobe of the pituitary gland in the brain.
→ Estrogen and Progesterone are produced in the ovaries.
1. FSH is released from pituitary gland
2. It stimulates the ripening of the follicle.
3. Growing follicle releases estrogen.
4. Estrogen increases the thickness of the endometrium and inhibits FSH + stimulates LH.
5. LH stimulates ovulation and the formation of the corpus luteum.
6. Corpus luteum produces progesterone which keeps endometrium intact + inhibits both FSH and LH.
7. If fertilization doesn't occur, corpus luteum degenerates and FSH is produced again.
In-Vitro Fertilization aka IVF
→IVF is when the egg and sperm cells meet outside the female's body.
→IVF is used on women who have blocked fallopian tubes, or cannot sustain pregnancy.
→Egg cells of woman who wants to be pregnant can be used, or donor egg cells.
1. Woman who is generating egg cells is treated with hormones so more than one follicle will ripen.
2. Needle is placed in follicle and egg cell is removed. repeated until all egg cells are taken
3. Egg cells are mixed with sperm cells, if quality is poor it is injected.
4. The fertilized egg cells are cultivated and are either placed inside uterus or frozen.
5. If all embryos are implanted successfully, can lead to multiple pregnancy that may result in premature delivery and a reduced change of survival for the babies.
Within this Blog we now have learned that:
→ The endocrine system composes of different hormones
→ The menstrual cycle utilizes 4 main hormones: FSH, LH, Estrogen and Progesterone
→ The usage and the logistics of IVF
→ The differences between nervous and endocrine system
That is all!
Written by Venetia (Biology)