1 / 46

Chapter 33 The Nervous System

Chapter 33 The Nervous System. Syllabus. The structure and function of the human nervous system. Describe the structure of the neuron. Outline impulse movement between nerves. Name & give the role of the 3 types of neuron -- sensory/motor/inter.

vester
Download Presentation

Chapter 33 The Nervous System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 33 The Nervous System

  2. Syllabus The structure and function of the human nervous system. Describe the structure of the neuron. Outline impulse movement between nerves. Name & give the role of the 3 types of neuron -- sensory/motor/inter. Outline the nervous system components: central nervous system (CNS).

  3. State location & function of hypothalamus, cerebellum & medulla oblongata Draw a labelled diagram of a cross section through the spinal. Describe the peripheral nervous system. State the mechanism & function of the Reflex arc/action. Outline disorders from NS disorders: paralysis/Parkinson's including: Cause/Prevention/Treatment

  4. The Nervous System • Organisms must be aware of what is happening around them as this affects their survival chances. • Co-ordination of an organism’s activities is carried out by thenervous system and the endocrine system. • A nervous system allows an organism to detect and respond to stimuli in its internal or external environment. • A stimulus is any change in your environment • e.g. a flash of light, a noise, a fly landing on your nose.

  5. The nervous system is divided into: • the central nervous system (CNS) = brain and spinal cord. • The brain keeps a check on internal organs and activities, such as the level of carbon dioxide orwater in theblood.

  6. the peripheral nervous system (PNS) = the nerves branchingfrom the CNS to all parts of the body.

  7. Nervous coordination involves: A stimulus is any change in your environment A receptor is a nerve cell that detects the stimulus A neuron is a specialised cell that carries electrical messages/impulses around the body. An impulse is an electrical message that is carried along aneuron. A response is a muscle or gland carries out the effect.

  8. A neuron is a nerve cell. There are three types of neurons. Sensory neurons carry messages from the sense organ tothe CNS. Motor neurons carry impulses from the CNS to muscles andglands. Interneurons connect motor and sensory neurons in the CNS. The nervous system

  9. Neurons or nerve cells - Structure function and types of neurons

  10. LEARNING CHECK • Co-ordination of an organism’s activities is carried out by what 2 body systems? • Distinguish between the CNS and PNS. • What is a neuron? • What is an impulse? • What is a stimulus? • What is a receptor? • Explain what is involved in Nervous coordination.

  11. The main parts of a neuron: • The cell body contains the nucleus and other organelles andproduces neurotransmitter chemicals. • A dendron / dendrites is a fibre that receives information and carry impulsestowards the cell body. • The axon is a long fibre that carries nerve impulses away from the cell bodies.

  12. Schwann cells form a myelin sheath. • The myelin sheath insulates the electrical impulses flowing in the neurons.

  13. Neuron structure

  14. A nerve impulse involves • A Synapse — region where two neurons come into close contact. • A Synaptic cleft—the gap between two neurons, bridged bychemicals (neurotransmitters).

  15. The central nervous system

  16. How are electrical messages carried from one neuron to the next: Neurotransmitter swellings / synaptic knobs produce neurotransmitters (chemicals) such as acetylcholine (ACh). that are released & diffuse across the synaptic cleft causing the production of an electrical impulse at the other side They are eventually broken down / destroyed by enzymes.

  17. SYNAPSE & NEUROTRANSMITTERS

  18. Nerve impulse transmission: • There is a threshold for the minimum stimulus needed for an impulse to travel. • The ‘all or nothing’ law says that: • - if the threshold is reached, an impulse travels • - if the threshold is not reached, no impulse travels. • The synapse

  19. LEARNING CHECK Name the main parts of a neuron and give one function of each. Distinguish between a sensory and motor neuron. Distinguish between synapse and synaptic cleft. What are neurotransmitters? Explain the Nerve impulse transmission.

  20. The Brain • The brain is composed of over 100 billion neurons, eachreceiving messages simultaneously from thousands of otherneurons. • The brain is protected by the skull bones, meninges (threemembranes) and cerebrospinal fluid.

  21. The cerebrumcontrols sight, Hearing, Intelligence & Memory cerebrum

  22. The hypothalamus controls Homostasis - the regulation of the internalorgans. hypothalamus

  23. The cerebellum co-ordinates voluntary muscles & balance cerebellum

  24. Medulla oblongata The medulla oblongata co-ordinates involuntary muscles e.g. the diaphragam.

  25. LEARNING CHECK Name the 4 main parts of the brain. State the location of the 4 main parts of the brain. State the function of cerebrum, hypothalamus, cerebellum, & medulla oblongata.

  26. The spinal cord is well protected by the vertebrae, meninges(three membranes) and cerebrospinal fluid. • It transmits impulses to and from the brain & • controls manyreflex actions.

  27. A cross-section through the spinal cord shows a small central canal, filled with cerebrospinal fluid, surrounded by an area of grey matter, shaped like the letter H.

  28. The spinal cord: In humans, 31 pairs of spinal nerves branch off from the spinal cord. Each spinal nerve has a dorsal root and a ventral root. The dorsal root consists of sensory neurons carrying information from the senses into the spinal cord. The dorsal root ganglion is a swelling that contains the cell bodies of the sensory neurons. The dorsal root ganglion white matter contains axons.

  29. The ventral root consists of motor neurons carrying information from the spinal cord to the muscles and glands. The cell bodies of the motor neurons are positioned within the grey matter of the cord. interneurons connect sensory and motor neurons.

  30. Interneuron REFLEX ACTION --- The Reflex Arc

  31. A reflex action is an automatic response to a stimulus. Reflex actions are: fast responses designed to protect the body

  32. Interneuron Suppose you touch a hot flame. The route taken along a receptor → sensory neuron → spinal cord → interneuron → motor neuron → effector, causes you almost instantly to pull your hand away.

  33. Knee Jerk Reaction • The Nervous System ( Animation )

  34. Nervous System Disorder • Parkinson’s disease • is a nervous disorder caused by a lack of dopamine in the brain • results in trembling limbs, a rigid body and inability to walk properly • cannot be prevented • is treated by physiotherapy and drugs – Levadopa.

  35. 4) The brain decides to move away the hand 3) Here another sensory neuron carries the signal to the brain 5) This impulse is sent by MOTOR NEURONS to the hand muscles (the effectors) via the spinal chord… 2) The impulse is carried by SENSORY NEURONS to the spinal chord 1) Receptors in your skin detect a stimulus 6) Which then moves the hand away Stimulus Receptor Sensory NeuronCoordinator Motor Neuron Effector Response Conscious actions A conscious action is one where the brain makes a considered response. Here’s what happens:

  36. LEARNING CHECK Draw a labelled diagram of a cross section through the spinal. State the mechanism & function of the Reflex arc/action. Distinguish between grey and white matter. Distinguish between dorsal and ventral root. What is meant by reflex action? Outline a disorder from the NS. What is it’s Cause/Prevention/Treatment?

  37. Quiz Human Responses (The Nervous system) • Sensory neurons transmit impulses to the _______ • 2. Motor neurons transmit impulses to the_____ • 3. The gap separating two neurons is called a ____ • 4. An impulse is carried across this gap by a _____ • 5. There are 3 types of neurons - sensory, motor and ____ • 6. Impulses are carried to the nerve cell body by a ____ • 7. Impulses are carried away from the cell body by an ____ • 8. Schwann cells make _________________ • 9. The membrane covering the brain is called the ____ • 10. A reflex action is an automatic response to a ______

  38. Human Responses (The Nervous system) 1. CNS (Central Nervous System) 2. Muscles/Glands 3. Synapse/ synaptic cleft 4. Neurotransmitter 5. Autonomic 6. Dendrite 7. Axon 8. Myelin/ Myelin sheath 9. Meninges 10. Stimulus

  39. Endocrine Cells involved Gland Message Chemical (Hormone) Carried by Blood Message sent to Cells throughout the body Received by Target organ Comparison of the endocrine and nervous systems - 1

  40. Comparison of the endocrine and nervous systems - 1

  41. Endocrine Speed of transmission Usually slow Effects Can bewidespread Duration long-lasting (hours) Comparison of the endocrine and nervous systems -- 2

  42. Comparison of the endocrine and nervous systems -- 2

  43. http://www.youtube.com/watch?v=YRwPMICvbT4&feature=youtube_gdata_playerhttp://www.youtube.com/watch?v=YRwPMICvbT4&feature=youtube_gdata_player • The Nervous System- Animation-Video for Kids

More Related