integrating, processing, and coordinating sensory input and motor output
all neural tissue outside of CNS
sensory information to the CNS and carries motor commands from the cns to the peripheral tissues and systems
PNS is divided into what two divisions?
afferent-carries sensory info to CNS efferent-carries motor commands to muscles and glands
afferent division begins at?
somatic sensory receptors
monitor skeletal muscles, joints, and the skin
visceral sensory receptors
monitor other internal tissues such as smooth muscle, cardiac muscle and glands
somatic nervous system
controls skeletal muscle contractions
autonomic nervous system
regulates smooth muscle, cardiac muscle, and glandular activity
activities of the somatic nervous system may be....
voluntary and involuntary
autonomic nervous system...
involuntary, usually outside of our control
what two types of neural tissue are there?
Neurons(impulse conduction) and neuroglia(supporting cells, can divide unlike neurons, common source of tumors)
parasympathetic vs sympathetic?
para-just chillin sympathetic-fight or flight
31 spinal nerves and 12 pairs of cranial nerves
general characteristics of neuroglial cells
smaller than neurons more numerous than neurons most found in brain and spinal cord source of tumors
CNS neuroglial cells
Astrocytes Microglia Ependyma Oligodenrocytes
controlling interstitial environment maintaining the blood-brain barrier performing repairs in damaged neural tissue guiding neuron development
smallest of glial cells, work as phagocytic cells in the CNS engulfing cellular debris, waste products and pathogens
produce spinal fluid
produces myelin and wraps axons
PNS gial cells
schwann cells(neurolemmocytes) satellite cells
regulate exchange of nutrients and waste products between the neuron cell body and the extracellular fluid
every peripheral axon whether unmyelinated or myelinated is coverd with Schwann cells; Supporting cells of the peripheral nervous system responsible for the formation of myelin.
plasmalemma of an axon
thick outermost coil of myelin sheath- bulging of Scwann cell contains nucleus and cytoplasm
the two anatomical subdivisions of the nervous system?
central and peripheral nervous system
what two terms are used to refer to the supporting cells in neural tissue?
glial or neuroglial
specifically what cells help maintain the blood-brain barrier?
astrocytes help maintain the blood-brain barrier
what is the name of the membranous coating formed around axons by oligodendrocytes?
myelin is what oligodendrocytes produce
identify the cells in the peripheral nervous system that form a covering around axons
in the PNS, schwann cells form a myelin covering around axons
what does the cytoskeleton of the perikaryon contain?
neurofilaments and neurotubules
what is a bundle of neurofilaments?
cytoplasm of an axon?
small neurons; cannot distinguish axons from dendrites; only found in CNS; functions are poorly understood
One dendrite and one axon; Receive limited inputs (special sense organs), rare, axons are not myelenated
located in the periphery of the pody, where it conveys sensory impulses; characterized by a single process that divides into two, and a cell body located in a sensory ganglia
have multiple dendrites and a single axon; most common type of neuron in CNS; all motor neurons that control skeletal muscles are this type
pseudounipolar neurons with their cell bodies located outside the CNS in peripheral sensory ganglia; form the afferent division of the PNS-deliver info to the CNS
axons of sensory neurons
somatic sensory neurons
monitor effects of external environment
visceral sensory neurons
transmit info about internal conditions and the status of other organ systems
sensitive to stimuli arising outside body (touch, pressure, pain receptors)
Type of sensory receptor that monitors the body's position in space.
monitor digestive, respiratory, cardiovascular, urinary, and reproductive systems
axons traveling away from the CNS
axons extending from the CNS to a ganglion
axons connecting the ganglion cells with the peripheral effectors
Changes that occur in the axon distal to the site of axonal damage; the axon swells up and becomes irregular; eventually, the axon and the terminals are broken down into fragments that are phagocytosed by adjacent macrophages and Schwann cells.
ability of the plasmalemma to conduct electrical impulses
an electrical impulse developed after the threshhold level has been reached, the membrane permeability to sodium and potassium ions changes
site where synapses permit communication between neurons and other cells
synapses which involved the release of a chemical neurotransmitter by the presynaptic neuron