{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Nervous_Teacher - Chapter 17 The Nervous System Nervous...

Info icon This preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 17 The Nervous System
Image of page 1

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

View Full Document Right Arrow Icon
Nervous Tissue 2 Major Categories of Nervous System 1. Central Nervous System The brain and spinal cord At midline of body 1. Peripheral Nervous System Nerves carrying messages from CNS to muscles and glands Sensory nerves carrying messages to the CNS
Image of page 2
Image of page 3

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

View Full Document Right Arrow Icon
3 Types of Nerves to Know Sensory Nerves , Interneurons & Motor Nerves 1. Sensory Nerves - carry information to the CNS 2. Interneuron – a bridge between a sensory and motor nerve 3. Motor Nerves – carry response from the CNS to an effector – a gland or muscle that creates an action
Image of page 4
Image of page 5

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

View Full Document Right Arrow Icon
Image of page 6
Anatomy of a TypicalNerve Cell Sensory Neuron shown here Dendtrites Cell Body (Soma) Nucleus Axon Bulb Axon Myelin Sheath Node of Ranvier
Image of page 7

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

View Full Document Right Arrow Icon
Myelin Sheath / Nodes of Ranvier Formed by Schwann cells which secrete a fatty coating over the axon Acts like an insulation around a wire. Electrical signal jumps gap to gap because that is easier than travelling down the high resistance of the axon, itself. Gaps where Schwann cells do not myelinate are called the Nodes of Ranvier
Image of page 8
Image of page 9

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

View Full Document Right Arrow Icon
More on Myelin Gives nerves white appearance (= WHITE MATTER) MS (mutliple sclerosis) is a disorder where myelin is removed from nerve. Signal passes down axon, weakening. In case of optic nerve, this can cause loss of vision. Ultimately, muscular control is lost. If the breathing and respiration centres in the medulla are affected, the result is fatal. Long Axons – usually myelinated to help signal make it Short Axons – usually non-myelinated, since signal should not degrade over short distance Unmyelinated nerves = GRAY MATTER
Image of page 10
How does a Nerve Cell Pass an Electrical Signal? Nerve impulse carries information Impulse measured in mV Stages of Nerve Cell firing off a Signal 1. Resting Potential – electric potential before signal 2. Action Potential – potential of nerve when signal goes 3. Refractory Period – potential after signal has passed
Image of page 11

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

View Full Document Right Arrow Icon
Action potential Definition: an “all-or-none” change in voltage that propagates itself down the axon Naturally occurring action potentials begin at the axon hillock
Image of page 12
Resting Potential When not conducting an electrical impulse, the potential difference across the membrane is -65mV Inside of axon is negative compared to outside! Difference between inside/outside charge of membrane is needed to start a signal Similar to a battery, the ends must have a potential difference for current to flow
Image of page 13

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

View Full Document Right Arrow Icon
Image of page 14
Action potential Definition: an “all-or-none” change in voltage that carries on all the way down the axon, creating electrical impulse. Naturally occurring action potentials begin at the axon hillock = crest of the axon Action potentials do not occur anywhere else in a neuron – not in dendrites, not in cell bodies
Image of page 15

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

View Full Document Right Arrow Icon
More K+ Sneaks out than Na+ in!
Image of page 16
Image of page 17
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