Stimulus Response Lab
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 Take out your research on your disease/disorder. Explain your disorder to a partner. Each partner is going to share what they learned from each other!
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?
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.
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. Cell bodies create a tissue mass called ganglia.
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. *multipolar
Neuron Classification Motor Neurons (efferent): carry impulses out of brain or spinal cord to the effector and stimulate response.
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: neuroncapillary) 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 & unmyelinated axons in CNS Produced by some neuroglial cells Insulates neurons & increases efficiency of nerve impulses
Neuroglial Cells Oligodendron, astrocytes, and microglial cells
Neuroglial Cells
Do Now Which sub-division of the PNS is responsible for your heart beating? What is the difference between afferent and efferent neurons? What part of the neuron carries messages to the CNS? Where are bipolar neurons commonly found?
Objectives To explain how a nerve impulse occurs. To determine what types of stimuli elicit an action potential. To explain different things that inhibit an action potential. To understand components of a neuron that contribute to impulse velocity.
Cell Membrane Potential The membrane is electrically charged, “polarized” due to Na+ and K+ ions Greater concentration of sodium ions outside and potassium ions inside. Potassium ions pass through more easily Active transport (sodium/potassium pump) maintains balance This is essential in the propagation of a nerve impulse.
Resting Potential When a nerve cell membrane is undisturbed, the membrane remains polarized staying more negative on the inside and positive on the outside.
Threshold Potential If the nerve cell detects a change in light/temp/pressure it effects the resting potential and the membrane begins depolarizing. Sodium channels open and + ions flow in, making the inside less negative. Change in potential is proportional to the intensity of the stimulation. Stimulation + more stimulation before initial stimulation subsides is called summation. Once the threshold is reached, an action potential occurs.
Action Potential
Impulse Conduction Unmyelinated nerve = impulse conducted over the entire surface. Myelin insulates and prevents ion flow, would prevent conduction if it were continuous and didn’t have the nodes of ranvier. Myelinated nerve= impulse jumps from node to node and creates a saltatory response and is much faster than unmyelinated.
All-or-None Nerve impulses create an “all or none response”. Once the stimulus reaches threshold, it generates an action potential.
Action Potential Animation http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter8/animation__action_potential_propagation_in_an_unmyelinated_axon__quiz_2_.html
PhysioEx Lab “Neurophysiology of Nerve Impulses” Complete the physioEx lab. Answer the questions. You DON’T have to print the graphs. Complete the “review sheet” when you are done with your lab. You will have a LAB QUIZ next lab day on this material. (Next Wednesday)
Do Now How is an impulse generated? What are some ways to generate an impulse? List the different inhibitors that can prevent an action potential and how?
Objectives Identify the different components of a reflex arc. Explain different autonomic reflexes found throughout the body.
Article Read the article about impulses and answer the questions!
Responses How would you explain how your body responds to a stimulus? (use what you know about neurons)
Reflexes Ordinarily, a receptor sends a signal to the brain where the brain coordinates a response. What happens when you touch something hot?
Reflex Arc A reflex is a rapid action that happens without thought and does not involve the brain. Lets take a look… http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/human/thenervoussystemrev3.shtml
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
Study Guide Lab quiz Wednesday Test on Ch. 9 on Friday PhysioEx Lab due Wed Brain dissection lab due Friday