Chapter 12: Nervous System Flashcards
nervous system
function
- keeps controlled conditions within limits that maintain health and homeostasis
- responsible for behaviors, reasoning, intelligence, memories, sensations, movements
nervous system is composed of (7)
brain, cranial nerves, spinal cord, spinal nerves, ganglia, enteric plexus, sensory receptors
brain
contains? protected by?
protected by skull
contains over 90 billion neurons
12 pairs of ____ emerge from the base of the brain through the foramina of the skull
cranial nerves
nerve
description
bundle of hundreds of axons that serve a specific region of the body
spinal cord is an extension of what?
extension of the brain that begins at the foramen magnum of the skull and is protected by the vertebral column
foramen magnum
junction of brain stem and spinal cord
how many pairs of spinal nerves?
31
how many pairs of cervical nerves?
8
how many pairs of thoracic nerves?
12
how many pairs of lumbar nerves?
5
how many oairs of sacral nerves?
5
how many pairs of coccyx nerves?
1
ganglia
collections of cell bodies of neurons that reside outside the CNS
enteric plexuses regulate what?
help regulate the digestive system
sensory receptors
function
parts of neurons (specialized cells) that monitor changes in the internal or external environment
functions of the nervous system
sensory, integrative, motor
sensory functions
sense changes in the internal/external environment through sensory receptors
integrative functions
analyze the sensory info and make decisions for appropriate behaviors
how do motor functions react to stimuli
by initiating a response in the effector (skeletal, smooth, cardiac muscles or glands)
central nervous system (CNS)
what does it consist of?
brain and spinal cord
peripheral nervous system (PNS)
what does it consist of?
12 pairs of cranial nerves, 31 pairs of spinal nerves
sensory (afferent) fibers bring info from ____ to _____
brings info to the CNS
(PNS—>CNS)
motor (efferent) fibers bring info from _____ to _____
brings info to PNS (muscles + glands)
(CNS) —->(PNS)
PNS is divided into
somatic (voluntary), autonomic (involuntary), enteric nervous systems
somatic nervous system is made up of? (3)
somatic (body) cells, sensory (afferent) and somatic motor (efferent) nerves
somatic sensory fibers
arise from special sense organs (eyes, ears, tongue) or from pain, touch, temperature
somatic motor fibers
innervation?
sense organs in skin and muscles
- innervate skeletal muscles only
what types of nerves does the autonomic nervous system have? (2)
contains autonomic sensory (visceral afferent) and autonomic motor (visceral efferent) nerves
visceral sensory fibers
where do they arise
location
arise from stretch receptors in muscles, and sense organs in viscera that detect blood pressure, o2 + CO2 concentrations, Ph level etc
- involuntary
- found in organ walls
visceral motor fibers
innervate what types of muscle?
innervates smooth and cardiac muscle
motor part of the ANS make up (2)
consist of sympathetic + parasympathetic divisions
enteric nervous system
what does it consist of?
neurns in enteric plexuses that extend the length of the GI tract
- most neurons function independently of the ANS + CNS
enteric sensory fibers controls what?
contraction and organs in GI tract
ex: intestines, gall bladder, stomach, ass, esophagus
