{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

255 nervous system

255 nervous system - Two subdivisions of the nervous system...

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

View Full Document Right Arrow Icon
Two subdivisions of the nervous system o Central nervous system Brain Spinal cord o Peripheral Nervous system Cranial nerves Spinal nerves Ganglia 3 main functions of the nervous system o Collecting information o Processing and evaluating information o Responding to information 2 functional divisions of nervous system o Sensory nervous system o Motor nervous system Sensory nervous system o Afferent- Receives sensory information from receptors in PNS and transmits it to CNS o 2 subdivided systems Somatic sensory Voluntary (touch, pain, pressure, vibration) Visceral sensory Involuntary (impulses from viscera) Motor nervous system o Efferent- Send impulses from CNS to muscles and glands o 2 subdivided systems Somatic motor Voluntary o Impulses from the CNS that cause contraction of skeletal muscles Autonomic motor Involuntary o Impulses from CNS that regulate smooth and cardiac muscle and glands Cytology o Neurons (nerve cells) Electrically excitable cells that initiate, transmit, and receive nerve impulses o Glial cells Nonexcitable cells that support and protect neurons
Background image of page 1

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

View Full Document Right Arrow Icon
Neurons o Basic structural unit of nervous system o Conduct nerve impulses from one part of the body to another part o Features High metabolic rate Extreme longevity Nonmitotic Neuron structure o Cell body Contains: Nucleus Nucleolus Mitochondria Ribosomes and ER o Dendrites Toward cell body Short processes o Axon Away from cell body to other cells Anaxonic: do not have axon Axon hillock: region where axon connects to cell body o Axon collaterals Side branches of main axon o Telodendria Fine terminal extensions at end of the axon and its collaterals o Synaptic knobs Expanded regions at tip of telodendria Aka synaptic bulb, axon terminals, or synaptic button Structural Classification of neurons o Unipolar Single short process that branches like a T o Bipolar 2 processes, one dendrite and one axon o Multipolar Many dendrites and single axon Most common Functional Classification of neurons o Sensory Afferent Impulses from sensory receptors to CNS o Motor Efferent
Background image of page 2
From CNS to muscles or glands o Interneurons Facilitate communication between sensory and motor neurons Glial cells o Aka neuroglia o Found in CNS and PNS o Smaller than neurons and capable of mitosis o Physically protect and nourish neurons o More numerous than neurons Brain tumors more likely to be derived from glial cells than neurons o 4 types Astrocytes Ependymal Microglial cells Oligodendrocytes Astrocytes o Type of glial cell o Most abundant glial cell in CNS o Functions Maintain blood-brain barrier/regulate blood flow Regulate tissue fluid composition Form structural network Replace damaged neurons Assist neuronal development Ependymal o Ciliated cuboidal epithelial cells o
Background image of page 3

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

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

{[ snackBarMessage ]}