Science (3rd Quarter)

• Nervous System - connects all your body parts and transmits signals from one part to another. It is a system of cells, tissues and organs that regulates the body's responses to internal and external stimuli.
• Central Nervous system (CNS) - main processing for the entire nervous system. It consists of two main components.

  a.Brain

  b.spinal cord
• Brain - organ located within the skull that fuctions as organizer and distributor of information.
• 3 main parts of the brain:

  Cerebrum

  Cerebellum

  Brain Stem
• Cerebrum - large, upper part of the brain: controls activity and thought
• cerebellum - the part UNDER the cerebrum that controls POSTURE, BALANCE and COORDINATION.
• Brain Stem- part that CONNECTS THE BRAIN TO THE SPINAL CORD and CONTROLS AUTOMATIC FUNCTIONS such as breathing.
• Spinal Cord - serves as a channel for signals between the brain and the rest of the body. controls simple musculoskeletal reflexes.
• Peripheral Nervous System (PNS) connects the nervous system to the organs and the limbs.

  2 main divisions:

  a.somatic nervous system

  b.Autonomic nervous system
• Somatic Nervous System - associated with the VOLUNTARY CONTROL OF BODY MOVEMENTS and has two main parts:

  Spinal Nerves and Cranial Nerves
• Spinal Nerves- nerves that carry motor and sensory signals between the spinal cord and the body.
• Cranial Nerves - nerves fibers that carry information into and out of the brain stem.
• Autonomic Nervous System (ANS) system associated with INVOLUNTARY CONTROL OF THE BOdy movements

  2 subdivisions:

  • Sympathetic and Parasympathetic
• Sympathetic - activated when the body is in dynamic role or stress (e.g increased heart rate)
• Parasympathetic - maintains body functions and restores the body to normal or relaxed mode.
• nerve cells are called - neurons
• Neuron - has a cell body containing the nucleus.
• Dendrites - carry impulses towards the cell bodu
• Axons - carry impulses AWAY from the cell body.
• Axons can be grouped together into cable like bundles called NERVES.
• Stimulus - any factor in the environment that may TRIGGER a nerve imppulse.
• synapse - space between neurons
• Response - reaction to a condition or stimulus
• Endocrine System - composed of glands responsible in secreting chemicals called HORMONES to control various body processes.
• Hormone - h=chemical substance produced in the body that controls and regulates the activity of certain cells and organs.
• Menstrual Cycle - monthly shedding of the lining of your uterus that occurs before pregnancy.
• Menarche - first menstrual period.
• Menopause - time that marks the end f your menstrual cycle.
• Stages of Menstrual Cycle: Menstruation, Follicular Phase, Ovulation Phase, Luteal Phase
• Menstruation can last up to 3-7 days (or 5)
• In Follicular Phase, you should start counting from Day 1 NOT AFTER YOUR PERIOD.
• Ovulation occupies 5 days of your cycle (if 28 days ang cycle mo)
• Luteal Phase occupies 9 days of the cycle.
• Follicular phase - starts on the first day of period and lasts for 13-14 days.
• Ovulation Phase - when a mature egg (Ovum) is released from an ovary and moves along a fallopian tube.

  • can last from 16 to 32 hours
• Luteal Phase - cells in the ovary release progesterone and a small amount of estrgen
• Luteal Phase - If you get pregnant, your body will produce HUMAN CHORIONIC GONADOTROPIN (hCG) -lumalabas sa pregnancy tests
• Homeostasis - ability of an organism to maintain internal balance by regulating its processes.
• Homeo - similar

  Stasis - stability
• Feedback Mechanism - the process through which the level of one substance influences the level of another substance.