Final Exam - Final Exam Ch 48 and 49 The Nervous System...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Final Exam Ch. 48 and 49 The Nervous System Your brain has 100 billion neurons.. Overview of nervous system o Stimulus—activates input. Receiving afferent system—input o Process information—integration o Send out information=output—efferent system, ex. motor output. Response in effector. o Different types of efferent systems do different jobs. Organization of Nervous system—overview o Central nervous system (CNS) brain and spinal cord Input to CNS—integration output from CNS Integrates information Transmits signals Consists of Brain Spinal cord – jellylike bundle of nerve fibers Both contains spaces filled with cerebrospinal fluid o Cushions CNS o Helps supply CNS with nutrients, hormones, and white blood cells Meninges are layers of connective tissue protecting brain and spinal cord. Can cause meningitis Intervertebral disks should cushion nerves, but a herniated disk permanently presses on nerves causing pain. o Peripheral Nervous System – PNS – nerves that are outside the CNS. Somatic nervous system—voluntary Carries signals to and from skeletal muscles Mainly responds to external stimuli Autonomic nervous system (involuntary) Controls smooth and cardiac muscles Sympathetic (fight or flight; stimulatory) - prepares for intense, energy consuming activities. Parasympathetic (routine processes) - works with maintenance activities Two types of cells o Neurons—single nerve cells specialized for carrying electrical signals throughout the body—they have ion channels A nerve fiber is many neurons together Bundles of axons in the PNS that transport info to and from CNS
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Axons end in bulbs called synaptic terminals that release neurotransmitters Neurons are not like plumbing because they can determine the pathway of a signal separate of other cells. This duplication means that if one breaks down, the whole system does not shut down. Specialized cells will wrap around the axon. These cells are the lipid-filled myelin sheath and they insulate the electric current, speeding it up. Nodes are areas without the sheath. They are the only place the signal is transmitted. MS results in the dismantling of the myelin covering of CNS axons by body’s own immune system o Problem with coordination and muscle weakness. Myelin sheaths not completely formed when born – learn to walk Sensory neurons sensory input Interneurons integrate information to brain or CNS Motor neurons function in motor output o Glial cells Provide protection to neurons (like packing peanuts; their job is to protect.) Control some neural communication Regulate ion concentrations Provide nutrients Outnumber neurons 50 to 1 Four types Microglia protect Oligodendrocyte—axon myelination (CNS) Schwann cell—axon myelination (PNS) Astrocytes—support, release neurotransmitters o Replaced over the years and can cause brain tumors
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern