nervous system
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peripheral nervous system (ganglia)
groups of nerve cell bodies outside brain and spinal cord
peripheral nervous system
nerve fibres carry information to and from CNS 12 pairs of cranial nerves mixed nerves: carrying info into and out of brain 31 pairs of spinal nerves connected to spinal cord by 2 roots
ventral root
axons of motor neurons that have cell bodies in grey matter of spinal cord
dorsal root
axons of sensory neurons with cell bodies in dorsal root ganglion
divisions of PNS (sensory/motor)
Afferent (sensory) :carries impulses into CNS from sensory nerve receptors Efferent (motor): carries impulses AWAY from CNS
efferent somatic and autonomic respnsbility
somatic: cns to skeletal muscle autonomic: CNS to heart, involuntary glands and muscle (parasympathetic and sympathetic)
Autonomic Nervous System
Controls internal environment and involved mechanisms of it - Pathway involves 2 neurons, sympathetic and parasympathetic
ANS neutrotransmitter
acetylcholine or noradrenaline
parasympathetic
Maintains body in quiet conditions - Acetylcholine ‘rest or digest’
sympathetic
Strenuous Activity - Noradrenaline ‘fight or flight’
somatic
One motor neuron from CNS; no synapses or ganglion Responds to external environment; voluntary and involuntary
Functional Areas
Sensory; interpret impulses from receptors Motor; controls muscular movements Association; intellectual and emotional processes
Protection of the CNS
bone, meninges, cerebrospinal fluid their functions are - shock absorption, transport, support
meninges
• outer: dura -> tough fibers attached to bone • middle: arachnoid -> loose mesh of fiber • inner: pia ->blood vessels and connects to surface of CNS
Cerebrospinal fluid
• contains cells, proteins, urea, and salts • formed from blood • carries nutrients towards and waste away
afferent somatic and visceral
• Somatic: nerve cells from body - Visceral: impulses from internal organs