Science

• Reproductive System


  Main function is to produce egg and sperm cells; to transport and sustain these cells; to nurture the developing offspring; to produce hormones
• Menstrual Cycle


  1. Menstruation

  2. Follicular Phase

  3. Ovulation

  4. Luteal Phase
• Menstruation


  Commonly known as a period; uterus lining sheds and flows out of your vagina
• Follicular Phase


  Starts on the first day of your period and lasts for 13-14 days, ending in ovulation (Day 14); the pituitary gland in the brain releases a hormone to stimulate the production of follicles in the surface of an ovary
• Ovulation


  When a mature egg is released from an ovary and moves along a fallopian tube towards your uterus
• Luteal Phase


  After ovulation, cells in the ovary (corpus luteum) release progesterone and a small amount of estrogen. This causes the lining of the uterus to thicken in preparation for pregnancy; if a fertilized egg implants in the lining of the uterus, the corpus luteum continues to produce progesterone, which maintains the thickened lining of the uterus
• Corpus luteum


  If pregnancy does not occur, the corpus luteum dies, progesterone levels drop, the uterine lining sheds and the period begins again
• Estrogen


  Plays a role in ovulation and thickens the lining of your uterus (endometrium) to prepare it for pregnancy
• Progesterone


  Works by thickening your uterine lining and creating a good environment for a fertilized egg to implant
• Gonadotropin-releasing Hormone (GnRH)


  Causes the pituitary gland in the brain to make and secrete the hormones LH and FSH
• Follicle-stimulating Hormone (FSH)


  Produced by the pituitary gland which helps control the menstrual cycle and the production of eggs by the ovaries
• Luteinizing Hormone (LH)


  Plays an important role in the sexual development and functioning; triggers the release of an egg from the ovary
• Major Division and Parts of the Nervous System

  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)
• Central Nervous System (CNS)


  Serves as the main processing center of the entire nervous system. It consists of two main components: Brain and Spinal cord
• Parts of the Brain


  • Cerebrum
  • Cerebellum
  • Brain stem
• Cerebrum


  Large, upper part of the brain that controls activity and thoughts
• Cerebellum


  The part under the cerebrum that controls posture, balance and coordination
• Brain stem


  The part that connects the brain to the spinal cord and controls automatic functions such as breathing, digestion, heart rate and blood pressure
• Spinal cord


  Serves as channel for signals between the brain and the rest of the body and controls simple musculoskeletal reflexes without input from the brain
• Divisions of Peripheral Nervous System (PNS)

  • Somatic Nervous System
  • Autonomic Nervous System
• Parts of Somatic Nervous System

  • Spinal Nerves
  • Cranial Nerves
• Spinal Nerves


  Nerves that carry motor and sensory signals between the spinal cord and body
• Cranial Nerves


  Nerve fibers that carry information into and out of the brain stem
• Subdivisions of Autonomic Nervous System

  • Sympathetic
  • Parasympathetic
• Sympathetic


  Activated when the body is in a dynamic role or stress (e.g. increased heartrate and breathing, dilation of pupil, sweating)
• Parasympathetic


  Maintains body functions and restores the body to normal or relaxed mode
• Feedback Mechanism


  1. Negative Feedback

  2. Positive Feedback
• Negative Feedback


  Whenever there is a change in the normal state, the messages are sent to "increase" secretions if there is a fall below normal or to "decrease" secretions if there is a rise above normal to restore homeostasis (state of balance)
• Positive Feedback


  Amplifies changes rather than reversing them; the original stimulus is promoted rather than negated; (more, more, more)
• Protein Synthesis


  1. Replication

  2. Transcription

  3. Translation
• Replication


  The process by which DNA makes a copy of itself during cell division
• Transcription


  The process of making an RNA copy of a gene's DNA sequence
• Translation


  The process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins after the process of transcription of DNA to RNA in the cell's nucleus
• Codon


  A DNA or RNA sequence of three nucleotides that forms a unit encoding a particular amino acid
• Types of Mutations


  • Frameshift mutation
  • Nonsense mutation
  • Silent mutation
  • Missense mutation
• Frameshift mutation


  Refers to the insertion or deletion of nucleotide bases in numbers that are multiples of three
• Nonsense mutation


  A genetic alteration that causes the premature termination of a protein
• Silent mutation


  A form of mutation that does no cause a major change in the amino acid
• Missense mutation


  A DNA change that results in different amino acids being encoded at a particular position in the resulting protein
• Biodiversity


  Refers to every little thing, including plants, bacteria, animals and humans