Research… Each student should pick from the following list of disorders to research & answer the questions on the worksheet. Be prepared to share with the class. Bells Palsy Cerebral Palsy Multiple Sclerosis Parkinson’s Disease Huntington’s Disease Tay-Sach’s Amyotrophic lateral sclerosis (Lou Gherig’s Disease) Epilepsy Meningitis Alzheimer’s Disease Muscular Distrophy Any other nervous disorder you may find on the internet!

Do Now What did you learn from your skin sensitivity lab?

The Nervous System Chapter 9

Objectives To identify the basic structure of a neuron. To explain the main components of the nervous system. To compare and contrast the central nervous system and the peripheral nervous system. To differentiate between the somatic and autonomic nervous systems.

Nervous System Think back to when we talked about nervous tissue. What is it’s function? How does it go about doing this? General Functions: Sensory (detect change) Integrative (make sense of it) Motor (cause a response)

Structure of a Neuron Neuron= Nerve Cell Reacts to physical/chemical changes in surroundings Transmit information through nerve impulses to other neurons and other cells.

Structure of a Neuron

CNS vs. PNS CNS (Central Nervous System): Brain Spinal Cord PNS (Peripheral Nervous System): Cranial nerves Spinal Nerves

PNS Contains a sensory division and a motor division. Contains sensory receptors that convert info into a nerve impulse and transmit it back to the CNS to make sense of it. Monitors environmental changes such as light and sound Detects changes in homeostasis ( ex: temperature, oxygen level)

Motor Division Utilize peripheral neurons to carry impulses from the CNS to an effector which will cause a response Ex: muscle contraction, gland secretion, etc.

Motor Division Somatic Nervous System: Autonomic Nervous System: Controls skeletal muscle and voluntary movement. Autonomic Nervous System: Controls effectors that are involuntary Ex: heart, smooth muscle, certain glands

Lets put that all together…

Do Now What are the 2 divisions of the nervous system? Name as many parts of a neuron that you can remember. What are the 3 main functions of the nervous system? What are the 2 motor divisions? What is the difference between the sympathetic and parasympathetic nervous systems?

Objectives To identify and explain the 3 different structures of neurons. To compare and contrast sensory, motor, and interneurons and explain a general pathway. To determine the functions of the 5 types of neuroglia.

Autonomic Nervous System Parasympathetic Nervous System “Rest and Digest”- normal state Salivation Sexual arousal Lacrimation Urination Digestion Defication Sympathetic Nervous System “fight or flight”- triggered under stress Accelerated breathing & heart rate (increases blood flow) Inhibition or slowing of digestion Pupils Dilate Tunnel vision Increased muscle tension for extra strength & speed

Lets Review… General Neuron structure and action potential

Types of Neurons Multipolar: Many processes stemming from cell body. *most neurons in brain and spinal cord are multipolar

Types of Neurons Bipolar: Only two processes (one at each end) *found in eyes, nose, ears..

Types of Neurons Unipolar: One single process extending from cell body. one side of axon is the peripheral process associated with body part, other side is the central process that enters brain or spinal cord. *most common type Involved in pain, touch, proprioception, and visceral organ activity

Types of Neurons

Neuron Classification Sensory Neurons (afferent): Carry impulses from PNS to CNS Contain “receptor ends” at the tips of dendrites Changes outside the body stimulate receptor ends triggering an impulse *Most are unipolar

Neuron Classification Interneurons (association): Completely in brain or spinal cord Link neurons together. Direct impulses to appropriate parts for processing and interpreting *multipolar

Neuron Classification Motor Neurons (efferent): carry impulses out of brain or spinal cord to the effector and stimulate response. *multipolar

General Pathway

Neuroglial Cells *More numerous than neurons, support neurons in different ways. Microglial Cells: Phagocytize bacterial cells and cellular debris Oligodendrocytes: Provide insulating layers of myelin Astrocytes: Provide structural support join parts (ex: neuron→capillary) help regulate concentrations of nutrients and ions Form scar tissue in the CNS Ependymal Cells: Forms membrane that covers specialized brain parts and forms inner linings within the brain and spinal canal Schwann cells: Forms myelin sheath around axons.

Myelin A lipid that sometimes coats axons White matter = myelinated axons in CNS Gray matter = cell bodies in CNS Produced by some neuroglial cells Insulates neurons & increases efficiency of nerve impulses

Neuroglial Cells

Reflex Arc Ordinarily, a receptor sends a signal to the brain where the brain coordinates a response. Reflex: a rapid action that happens without thought and does not involve the brain Reflex Arc: The simplest nerve pathway resulting in reflex behavior

Reflex Arc Receptor- sense organ in skin, muscle, or other organ Sensory Neuron- carries impulse towards CNS from receptor Interneuron- carries impulse within CNS Motor Neuron- carries impulse away from CNS to effector Effector- structure by which animal responds (muscle, gland, etc).

Reflex Arc

Types of Reflexes

Babinski Reflex http://vimeo.com/14714777