THE NERVOUS SYSTEM

1. THE NERVOUS SYSTEM CHAPTER 10 MEDICAL TERMINOLOGY

2. FUNCTION OF THE NERVOUS SYSTEM Have you ever wondered what causes your body to do the things it does? • Control of the body’s billions of cells is accomplished by • the nervous system • the endocrine system • Parts of the nervous system communicate information to body structures

3. ORGANS OF THE NERVOUS SYSTEM • BRAIN • SPINAL CORD • NERVES OF THE BODY Let’s examine each of these in detail

4. NERVES • Nerves are a combination of cells • Nerves are a group of impulse carrying fibers that connect the brain and spinal cord with other parts of the body • Other terms associated with nerves are: A Ganglion A Plexus Receptors

5. NEURONS What is a neuron? • Neurons are the basic cells of the nervous system • Each neuron consists of 3 parts CELL BODY DENDRITES AXON

6. Jugular vein DENDRITES Branch like projections off the cell body Receive impulses and conduct the impulses to the cell body DENDRITES/AXONS

7. AXONS Axons look like elongated projections Axons transmit impulses away from the cell body Groups of wrapped axons are fascicles DENDRITES/AXONS • DENDRITES • Branch like projections off the cell body • Receive impulses and conduct the impulses to the cell body

8. NEURONS There are 3 types of neurons according to the direction in which they transmit impulses • SENSORY NEURONS • MOTOR NEURONS • INTERNEURONS

9. NEUROTRANSMITTERS What are neurotransmitters? • Chemicals by which neurons communicate. • This chemical substance helps impulses jump across the synapse so the impulse can continue along its pathway or reflex arc

10. NEUROGLIA • Neuroglia are supportive and connective cells • They do not transmit impulses • They hold the functioning neurons together

11. DIVISIONS OF THE NERVOUS SYSTEM The nervous system is divided into 3 parts: • Central Nervous System • Peripheral Nervous System • Autonomic Nervous System Let’s examine each of these systems

12. CENTRAL NERVOUS SYSTEM The Central Nervous System consists of: • Brain • Spinal Cord

13. THE BRAIN DIVISIONS OF THE BRAIN • Brain Stem Medulla Oblongata Pons Midbrain • Cerebellum • Diencephalon • Cerebrum

14. THE BRAIN STEM • Medulla oblongata is located at the lowest part of the brain and consists of gray and white matter • Pons consists of gray and white matter and is situated at the base of the brain where the nerve cells cross from one side of the brain to control the opposite side of the body • Midbrain consists of gray and white matter

15. THE BRAIN AND ITS PARTS • Cerebellum the 2nd largest part of the brain • Cerebrum the largest and uppermost part of the brain. It’s divided into 4 lobes

16. DIENCEPHALON • The diencephalon is a small part of the brain and consists of: • Hypothalamus • Thalamus

17. THE SPINAL CORD • The main function of the spinal cord is to carry nerve impulses that affect the limbs and lower parts of the body • Both the brain and spinal cord are protected by the meninges and cerebrospinal fluid

18. MENINGES & FLUID • The meninges consists of 3 layers of tissue The Dura Mater The Arachnoid Membrane The Pia Mater • Cerebrospinal Fluid is a clear, colorless fluid that flows throughout the brain and around the spinal cord and helps to cushion these organs

19. PERIPHERAL NERVOUS SYSTEM • Consists of: Crainal Nerves Spinal Nerves • There are 12 pairs of crainal nerves • There are 31 pairs of spinal nerves and they are names after the artery they accompany or the body part they innervate

20. AUTONOMIC NERVOUS SYSTEM • The autonomic nervous system consists of motor neurons. There are 2 divisions of the autonomic nervous system • Sympathetic Nervous System • Parasympathetic Nervous System