Human Reproductive Pathway and Menstrual Cycle

Human Reproductive Pathway

• The seminiferous tubules are located in the testes. Their function is to produce sperm and secrete testosterone.
• The fallopian tubes (oviducts) aid in the movement of non-motile eggs. Cilia in the fallopian tubes create a current to move the egg towards the uterus.

Menstrual Cycle

• Follicle-Stimulating Hormone (FSH): Stimulates follicle growth in the ovaries and estrogen production.
• Luteinizing Hormone (LH): Triggers ovulation and stimulates the formation of the corpus luteum.
• Estrogen: Thickens the endometrial lining and regulates FSH and LH levels.
• Progesterone: Maintains the endometrial lining for potential implantation and inhibits further ovulation.
• Luteal Stage: Progesterone secretion peaks, maintaining the uterine lining.
  • Estrogen levels rise to support uterine lining.
  • FSH and LH are inhibited by negative feedback loops.
• Negative Feedback Loop (for testosterone): Maintains homeostasis by reducing the output when levels are sufficient.
  • Hypothalamus releases GnRH, stimulating the pituitary to secrete LH and FSH.
  • LH stimulates testosterone production in the testes.
  • High testosterone levels inhibit GnRH and LH release, reducing further testosterone production.

STIs

• Hepatitis is a viral STI.
• Bacterial STIs are treated with antibiotics (e.g., penicillin).
• Viral STIs are managed with antiviral medications but cannot be cured.

Human Development

• The critical period is a time when organs form and are sensitive to external factors like teratogens.
• The blastocyst is a hollow ball of cells located in the uterus during implantation.

Extra-Embryonic Membranes

• The chorion facilitates gas exchange and nutrient transfer between the mother and embryo.
• The amnion contains amniotic fluid and ruptures during "breaking water".

Teratogens

• Teratogens like drugs and alcohol can cross the placenta and impact fetal development, causing abnormalities despite separate blood supplies.
• Alcohol leads to Fetal Alcohol Spectrum Disorders (FASD), impacting growth, facial features, and cognitive abilities.

Trimester Events

• First Trimester: Organogenesis (major organ formation).
• Second Trimester: Rapid growth and detailed organ development.
• Third Trimester: Organ maturation, including fat deposition for thermoregulation.
• Digestive and respiratory systems mature during the third trimester.

Stages of Childbirth

• Dilation stage: Cervical dilation to 10 cm, regular contractions, and cervical thinning (effacement).
• Positive Feedback Loop (childbirth): Baby's head pressure triggers oxytocin release, stimulating contractions for further labor.

Monitoring Health of Fetus

• Ultrasound: Uses sound waves to create fetal images for growth, position, and abnormality assessment.
• Amniocentesis: Extracts amniotic fluid for genetic abnormality testing (e.g., Down syndrome).

Causes of Infertility

• Sterility: Permanent inability to conceive.
• Infertility: Difficulty conceiving after a year of trying (not necessarily permanent).
• Male infertility: Blocked vas deferens prevents sperm exit.
• Female infertility: Blocked fallopian tubes prevent egg and sperm meeting.

Solutions to Infertility

• Abnormal endometrium: Surrogacy or IVF for implantation.
• Oviduct blockage: IVF for fertilization outside the body, followed by embryo implantation.
• Low sperm count: ICSI (injecting a single sperm into an egg) during IVF.

Stem Cells

• Stem cells are undifferentiated cells capable of developing into specialized cell types.
• Stem cell research aims at regenerating damaged tissues and treating diseases like Parkinson's and diabetes.
• Stem cell advantage: No immune rejection, originating from the same individual.
• Stem cell disadvantage: Limited differentiation potential compared to embryonic stem cells.

Birth Control Methods

• Hormonal methods: Oral contraceptives (e.g., estrogen and progesterone) prevent ovulation.
• Barrier methods: Diaphragm is placed over the cervix blocking sperm entry.

Explore the intricacies of human reproductive pathways and the menstrual cycle with this quiz. Learn about the roles of hormones like FSH, LH, estrogen, and progesterone, as well as the functions of the testes and fallopian tubes. Test your knowledge on the processes involved in reproduction and menstrual regulation.