The Nervous System

1. The Nervous System Section 35-3: Divisions of the Nervous System

2. Do Now 3/1/13 • What is the process that keeps internal conditions relatively constant despite changes in the external environment? • In a resting membrane of a neuron, what is the overall charge inside? What is the charge outside? • During an action potential, what happens to the charges? • What chemical is released in the synapse?

3. The Central Nervous System (CNS) • The central nervous system relays messages, processes information, and analyzes information • Control center of the body • Consists of the brain and spinal cord

4. The Central Nervous System (CNS) • Meninges = 3 layers wrapped around brain and spinal cord • Cerebrospinal fluid (CSF) = bathes brain and spinal cord and protects the central nervous system

5. The Brain • The Cerebrum • Largest part of the human brain • Voluntary and conscious activities • Site of intelligence, learning, and judgment • Each half deals with the opposite side of the body

6. The Brain • The Cerebellum • 2nd largest region of the brain, known as the “little brain.” • Coordinates and balances the actions of the muscles

7. The Brain • The Brain Stem • Connects the brain and spinal cord • Consists of the Pons and Medulla Oblongata • Controls blood pressure, heart rate, breathing, swallowing, visceral organs (autonomic)

8. The Brain • Thalamus • Receives messages and relays messages to proper regions of the cerebrum for processing • Hypothalamus • Control center for recognition • Analysis of hunger, thirst, fatigue, anger, and body temperature • Coordinates nervous system with the endocrine system

10. The Spinal Cord • Main communication link between the brain and the rest of the body • 31 pairs of spinal nerves branch out to communicate information to different parts of the body • Reflexes are processed directly to the spinal cord • Reflex = quick automatic response to a stimulus

11. The Peripheral Nervous System (PNS) • Outside of the Central Nervous System • Divided into the sensory division and motor division • Sensory Division of the PNS transmits impulses from sense organs to the CNS. • Motor Division transmit impulses from the CNS to the muscles or glands.

12. The Peripheral Nervous System (PNS) Somatic Nervous System • Regulates activities under conscious control • Some somatic nerves are also involved with reflexes that can act with our without conscious control

13. The Peripheral Nervous System (PNS) • Reflex arc = involves sensory neuron, motor neuron and effector (sometimes interneurons) • Neurons in spinal cord automatically activates motor neurons before information relayed to brain

14. The Peripheral Nervous System (PNS) • Autonomic Nervous System • Regulates activities that are automatic, or involuntary (not under conscious control). • Subdivided into 2 parts: • Sympathetic nervous system (fight and flight) • Parasympathetic nervous system (rest) • Opposing effects of sympathetic and parasympathetic help maintain homeostasis. • Ex. Heart rate increased by sympathetic but decreased by parasympathetic

15. Due Today 3/1/13 • Do the Quick Lab on page 903. You will need safety goggles, a sheet of scrap paper, and another sheet of paper to answer the questions. • Do 35-3 Section Assessment #1, 3-6 on page 905.

16. Do Now3/5/13 • Which part of the brain is involved in balance and coordination? • Which part of the brain is involved in controlling heart rate, blood pressure, visceral organs, and body temperature? • Which part of the brain is involved in learning? • What is the CNS made of? • What is the PNS made of? • What does the Autonomic Nervous System control? • What does the Somatic Nervous System control? • What are the two parts of the Autonomic Nervous System? • Which one deals with fight or flight? • Which one deals with rest?