Endocrine System - Reproduction System

• The Endocrine System is composed of different glands that secrete hormones regulating metabolism, growth, development, mood, and reproduction
• Hormones are organic substances released by endocrine glands directly into the bloodstream
• Pituitary gland:

  • Produces hormones that stimulate growth and control the functions of other glands
  • Hormones produced: Oxytocin, Growth Hormones(GH), Prolactin(PRL), Luteinizing Hormone(LT), Follicle Stimulating Hormone(FSH), Adrenocorticotropic Hormone(ACTH), Antidiuretic Hormones(TSH), Thyroid Stimulating(TSH)
  • Location: at the base of the brain
• Thyroid gland:

  • Produces hormones that regulate body metabolism and storage of calcium in bones
  • Hormones produced: Thyroid hormone
  • Location: In front of the neck and below the voice box
• Parathyroid gland:

  • Produces hormones that control calcium levels in the body and normalize bone growth
  • Hormone produced: Parathormone
  • Location: in the neck
• Thymus gland:

  • Produces hormones that enable the body to produce T-cells before puberty
• Adrenal gland:

  • Produces hormones that help regulate metabolism, immune system, blood pressure, response to stress, and other essential functions
  • Hormones produced: Adrenaline and others
  • Location: on top of the kidneys
• Pancreas gland:

  • Produces hormones that regulate blood sugar levels
  • Hormones produced: Insulin and Glucagon
  • Location: behind the stomach
• Reproductive System:
• Testes (males):

  • Produces hormones controlling maturation of sperm and development of secondary male sexual characteristics
  • Hormone produced: Testosterone
  • Location: Scrotum
• Ovaries (Females):

  • Produces hormones influencing development of secondary female sexual characteristics, maturation of egg cells, and ovulation
  • Hormones produced: Estrogen and Progesterone
  • Location: pelvic area
• Pineal gland:

  • Produces a hormone that regulates the biological clock in some animals
  • Hormone produced: Melatonin
  • Location: in the brain
• Male reproductive system produces male gametes or sperm cells, transfers them to the female

  • Female reproductive system produces female gametes/ovum, receives male gametes, and carries the baby throughout development
• Scrotum regulates the temperature of the testes, with sperm being best at 35°C
• External Structure:
• Penis:

  • Deposits sperm into the vagina during mating
• Scrotum:

  • Hangs behind the penis, contains the testicles, acts as a climate control system for the testes
• Testis:

  • Responsible for making testosterone and producing sperm cells
• Epididymis:

  • A long coiled tube that carries, stores, and brings sperm to maturity
• Internal Structures:
• Vas deferens:

  • Transports mature sperm to the urethra in preparation for ejaculation
• Ejaculatory Duct:

  • Formed by the fusion of the vas deferens and the seminal vesicles
• Urethra:

  • Carries urine from the bladder to outside the body
• Seminal vesicles:

  • Produces a sugar-rich fluid (fructose) providing energy for sperms and aiding in motility
• Prostate gland:

  • Contributes additional fluid to the ejaculate and nourishes the sperm
• Cowper's gland:

  • Also called Bulbourethral gland, produces a clear, slippery fluid that lubricates the urethra and neutralizes acidity from urine drops
• Homeostasis:

  • Maintains the balance of the body
• Male: Spermatogenesis

  • Female: Oogenesis
• Testes are inside the scrotum, keeping them cooler than the rest of the body for sperm production
• Organs of sperm production:

  • Testes contain seminiferous tubules where sperms are produced, which then travel to the epididymis for storage
• Organs of sperm transfer:

  • Testes produce sperm cells, and the penis transfers sperm to the female reproductive tract
• During sexual activity, sperm move from the vas deferens into a short ejaculation
• Pituitary Hormone Effects:

  • LH and FSH stimulate spermatogenesis and testosterone secretion by the testes
  • Hypothalamus releases GnRH into the anterior pituitary, adding FSH to Sertoli cells and LH to Leydig cells for positive feedback
  • Leydig cells add protein to Sertoli cells to help produce sperm, signaling fullness using inhibin and testosterone
• Testes Hormone Effects:

  • Testosterone and inhibin inhibit the secretion of GnRH by the Hypothalamus and LH and FSH by the pituitary
  • Hypothalamus sends GnRH to the pituitary gland, then sends FSH and LH to the ovary, leading to the production of Estrogen/progesterone in the uterus
  • Estrogen and progesterone provide negative feedback to the pituitary gland and hypothalamus to inhibit further hormone release
• Events in the uterine cycle:

  • Menstrual Phase (1-4): Menstruation occurs
  • Follicular Phase (5-13): Follicle matures and endometrium develops
  • Ovulation (14): Ovary releases an egg
  • Luteal Phase (15-28): Follicle becomes the corpus luteum and endometrium prepares for an egg