PSYC-2900 Chapter 3.2

peripheral nervous system (PNS)

a nervous system made of cranial and spinal nerves, and the peripheral ganglia. it is divided into the somatic and autonomic nervous systems

somatic nervous system

a division of the PNS that receives sensory information and sends motor signals to skeletal muscles and controls voluntary bodily functions

autonomic nervous system

a division of the PNS that regulates smooth muscle, cardiac muscle, and glands and controls involuntary bodily functions by regulating heart rate, blood pressure, respiration, digestion, and sexual arousal

afferent fibres

convey sensory information from PNS to CNS

efferent fibres

convey motor information from CNS to muscles and glands

vagus nerve

a cranial nerve that regulates organs in the thoracic and abdominal cavities

cranial nerves

olfactory (s), optic (s), oculomotor (m), trochlear (m), trigeminal (b), abducens (m), facial (b), auditory (s), glossopharyngeal (b), vagus (b), spinal accessory (m), hypoglossal (m)

(on old olympus’ towering top a finn and german valtz and hop)

(some say money matters but my brother says big brains matter more)

spinal nerves

31 pairs contained in the human spinal cord (cervical, thoracic, lumbar, and sacral) made of afferent/sensory axons and efferent/motor axons

dermatome

an area of skin innervated by an afferent

(i.e. connected to a specific nerve root on the spine)

myotome

an group of muscles that is supplied by an efferent

(i.e. controlled by a single spinal nerve)

parasympathetic nervous system

a division of the autonomic nervous system that helps the body rest and relax

(e.g. constricts pupils, stimulates salivation, constricts breathing, stimulates digestion, stimulates gallbladder, contracts bladder, stimulates sex organs)

also known as the craniosacral system

sympathetic nervous system

a division of the autonomic nervous system that activates the body’s fight, flight, or freeze response

(e.g. dilates pupils, inhibits salivation, accelerates heartrate, facilitates breathing, inhibits digestion, stimulates release of glucose, secretes epinephrine and norepinephrine, relaxes bladder, inhibits sex organs)

also known as the thoracolumbar system

thoracolumbar system

a part of the autonomic nervous system, consists of the sympathetic nerves that emerge from the thoracic and lumbar regions of the spinal cord, including the preganglionic neurons, sympathetic ganglia, and postganglionic neurons

also known as the sympathetic nervous system

preganglionic neurons

a part of the thoracolumbar system that originates in the intermediate zone and has an axon that exits through the ventral root to join the spinal nerve

sympathetic ganglia

a part of the thoracolumbar system that forms the sympathetic ganglion chain, which sits adjacent to the spinal column

postganglionic neurons

a part of the thoracolumbar system that includes neurons on the other side of the synapse. they target organs such as intestines, stomach, kidneys, and sweat glands, and their main neurotransmitters are epinephrine and norepinephrine