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The Nervous System: CNS & PNS


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The Nervous System: CNS & PNS

  1. 1. Life Science Human Body Systems Peripheral & Central Nervous System
  2. 2. Bonus: Name as many innate immune defenses as you can. - Skin barrier, mucus membranes, coughing/sneezing, phagocytes, inflammation (histamines/mast cells), fever, vomiting, anti-microbial saliva & tears, stomach acid, competing beneficial microbes 1. What do endocrine glands produce? • Hormones 1. Name at least 3 endocrine glands. • pituitary, hypothalamus, pineal, ovaries, adrenal, thyroid, pancreas, testes, placenta 1. A clear, watery fluid that comes from plasma which has seeped into the spaces between cells near capillaries is called • Lymph 1. True or False? Lymph nodes contain immune cells which filter pathogens from blood before returning the fluid back to the circulatory system. • True (lymph nodes filter interstitial plasma) 1. Which type of white blood cell (WBC) makes antibodies that fight off infection? • B cells In your lab notebook, please answer as best you can: Week 24 Review Quiz
  3. 3. The Nervous System • Central Nervous System (CNS) – Brain – Spinal Cord • Peripheral Nervous System (PNS) – Nerves that connect all your body parts to the spinal cord • Somatic nerves (voluntary) – Motor (muscle) & sensory (senses) • Autonomic nerves – heart, respiration, digestion (involuntary)
  4. 4. Central Nervous System (CNS) • Cerebrum (Cerebral Cortex) – divided into 4 lobes – thinking, movement, memories, sensory processing, vision, speech • Cerebellum – posture, balance, muscle coordination, muscle memory • Brain stem – basic body functions (breathing, heart rate, consciousness, sleep)
  5. 5. Mr. Egghead Demo Meninges surrounding the Brain Cerebrospinal fluid provides: •Protection •Buoyancy •Nourishment Meningitis = infection or inflammation of the meninges
  6. 6. Does Brain Size Matter? pig dolphin human • Men have bigger brains than women – Does brain size/volume indicate intelligence?
  7. 7. Wk 24 Experiment Hemisphere Dominance Brain Dominance Quiz • Right hemisphere – controls left side of body – art, writing – creativity, intuition, emotion, imagination • Left hemisphere – controls right side of body – math, science – organization, sense of time, logic
  8. 8. Inside the Brain • Thalamus – directs incoming sensory messages to proper area of brain • Hypothalamus – regulates hunger, thirst, and body temperature • Corpus Callosum – connection between hemispheres of the cerebrum that allows signals to go between
  9. 9. CNS - Spinal Cord • Information Superhighway – Carries brain messages out to body • muscles, glands, organs, etc. – Takes sensory information from body up to brain • touch, heat, pain • blood oxygen & sugar levels • stomach contents, taste
  10. 10. Peripheral Nervous System • Afferent Nerves (arrives in the brain) – Sensory neurons conduct messages from skin & sense organs to the brain – Visceral sensory neurons bring info from visceral organs (muscle stretch, blood O2 & sugar levels, arterial pressure and what's in the stomach) up to the brain • Efferent (exits the brain) – Somatic motor nerves take commands from spinal cord to muscles – Autonomic nerves convey signals from the brainstem & hypothalamus to the heart, diaphragm/ribs, digestive tract, glands, blood vessels, etc.
  11. 11. CNS PNS PNS & CNS Work Together Carotid body senses low blood O2 levels & sends message Brain stem receives/interprets message, sends new message out spinal cord spinalcord Ribs & Diaphragm receive message and breathing rate speeds up O2 levelsgo up  Is this SOMATIC or AUTONOMIC?  Which are sensory nerves? Motor nerves?
  12. 12. Reflex Arc • Sometimes quick action is needed – No time to "think" about moving – CNS is bypassed, so reaction time quickened – Realization of pain reaches brain after movement occurs Animation
  13. 13. Test Your Reflexes - The nervous system’s main job is: 1. collecting SENSORY INPUT 2. taking sensory info to the brain for INTEGRATION 3. sending instructions that result in MOTOR OUTPUT - The central nervous system (CNS) = the BRAIN & SPINAL CORD - The peripheral nervous system (PNS) = SENSORY & MOTOR neurons - A REFLEX ARC is when a sensory nerve triggers a motor nerve to react before the brain has a chance to process information.
  14. 14. What is a Nerve? • There are over 100 billion neurons in the brain alone. – This doesn't even count "helper" nerve cells (neuroglia) • Bundles of neurons form each nerve in your body • Neurons can only send info one way Info IN Info OUT
  15. 15. Synapses - where neurons meet  Neurons never touch!  Chemicals (neuro- transmitters) are released  Triggers an electrical current to run length of the next cell Animation
  16. 16. Neural Pathway Brain  Spinal Cord  Peripheral Motor Nerve(s)  Muscle Synapse Synaptic transmission
  17. 17. Neuron Relay Let’s make a neural pathway! • Left hand = the dendrites of a neuron • Your body is the cell body (soma) • Right arm = an axon (R hand holds neurotransmitters) • Your right hand is the terminal button which releases neurotransmitters into the synapse. • Your “neurotransmitters” should be unique. (Different neurons use many different types of neurotransmitters.)
  18. 18. Drugs & Alcohol on the Brain • Illegal drugs have many harmful affects on the brain: – Distortion of reality – Worsening of existing mental or medical conditions – Damaged brain cells – Addiction • Alcohol slows the transmission of nerve signals, resulting in: – Uncoordinated muscle control (slurred speech is caused by inability to correctly control the muscles used in forming words.) – Sedation (slowed neural response, loss of self-control & reasoning) – False sense of confidence – Addiction