My_Ch48_lecture_rev_08(2009050122183136)

My_Ch48_lecture_rev_08(2009050122183136) - Chapter 48:...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 48: Nervous System Purpose: to understand how neurons, as well as how the nervous system works What you MUST know in Ch 48: Comparative nervous systems (on your own; p 976-978) Neuron structure Knee-jerk reflex Role of glial cells Production of action potential Conduction of action potential Synaptic events Types of neurotransmitters Parasympathetic vs. sympathetic systems Role of medulla, cerebrum, cerebellum Limbic system Neuron structure (neuron = nerve cell) Motor neuron above; Sensory neuron below: Parts of the neuron include:
Background image of page 1

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

View Full DocumentRight Arrow Icon
Cell body —contains the nucleus, and organelles Dendrite —extends from the cell body; stimulus receptor Axon —long extension of the cell body that sends nerve impulses Schwann cells form the myelin sheath , which covers the axon, acting as an insulator and speeding up the movement (conduction) of the electrical impulse. Nodes of Ranvier are gaps in the myelin sheath; the impulse jumps from node to node (= saltatory conduction )—this is faster (fig 48.9, p 970) Axons end in synaptic terminals , which relay signals via neurotransmitter release to other cells 3 types of neurons: Sensory neurons (= afferent neurons ) receive the stimulus. The sensory neuron pictured above receives sensory touch or hot/cold input from the skin Sensory neurons in the retina (eye) receive light input Motor neurons (= efferent neurons —result in an effect) stimulate target effector cells that respond to the stimulus sensed by the sensory neurons. The motor neuron above stimulates muscle contraction Motor neurons stimulate sweat glands to release sweat for thermoregulation, or stomach cells to release gastrin Interneurons (or association neurons) in the spinal cord or brain relay impulses from sensory neurons to motor neurons. They function as integrators , evaluating sensory input to quickly determine the appropriate motor response.
Background image of page 2
This is what your doctor checks by tapping just below your knee (patellar tendon) with a reflex hammer. AKA spinal reflex arc http://www.biologymad.com/NervousSystem/nervoussystemintro.htm From a European site; neurone = neuron See fig 48.4, p 963 Sensory neuron receptors receive sensory input from the patellar tendon being struck and the signal is sent to the interneuron in the spinal cord which sends the message directly to the motor neuron in the quadriceps muscle (upper leg) which results in the knee kicking out provides the body with an immediate response to danger, without needing the brain to assess and filter out information for a response YOU DO NOT NEED YOUR BRAIN FOR THE SPINAL REFLEX ARC! So testing your knee-jerk reflex doesn’t indicate that your brain is fully functional. But it does
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/29/2011 for the course BIO 020.152 taught by Professor Pearlman during the Fall '08 term at Johns Hopkins.

Page1 / 11

My_Ch48_lecture_rev_08(2009050122183136) - Chapter 48:...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online