chapter 13 bold words

Sensory division

detects both internal and external stimuli; general sense receptors detect stimuli from skin;

special sensory receptors detect stimuli from special sense organs

Somatic sensory division

detects both internal and external stimuli

Visceral sensory division

Relays internal information

Motor division

consist of motor neurons, carry out motor functions of nervous system: subdivisions based on organs that neurons contact

Somatic motor division

responsible for voluntary motor functions; composed of motor neurons which directly trigger skeletal muscle contractions

Visceral motor division

responsible for maintaining many aspects of homeostasis by controlling involuntary motor functions in the body

Sympathetic nervous system

Involved in digestion and maintaining bodies homeostasis physical work

Parasympathetic system

involved in digestion and maintaining bodies homeostasis at rest

Peripheral nerves

main organs of PNS; consists of axons of many neurons bound together by connective tissues

Mixed nerves

contain both sensory and motor neurons

Spinal nerves

originate from spinal cord and innervate structures below head and neck; anatomical structures associated with this group of nerves include: anterior root and posterior root

Posterior root

features a swollen area that houses cell bodies of sensory neurons

Epineurium

outer most layer of connective tissues that holds motor and sensory axons together

Fascicles

small groups of bundled axons surrounded by connective tissues called perineurium

Endoneurium

Each individual axon within a fascicle is surrounded by its own connective tissue called

Cranial nerves

Attach to brain and mostly innervate structures in head and neck not formed by fusion of sensory and motor roots

Spinal nerve

Short and divides into two following mixed nerves both carry somatic and sensory information

Posterior Ramus

travels to posterior side of the body

Anterior ramus

travels to the anterior side of the body and or the the upper or lower limb

nerve plexuses

Anterior rami of cervical, lumbar, and sacral spinal nerves each merge to form complicated networks of nerves called

phrenic nerve

one way to get rid of hiccups

intercostal nerve

anterior ramus travels between two ribs

Sciatic nerve

Longest and largest nerve in the body; contains axons from both anterior and posterior division of sacral plexus

Exteroceptors

usually close to body’s surface; detect stimuli originating from outside body

Interoceptors

usually found in body’s interior detect stimuli originating from within body itself

Mechanoreceptors

depolarize in response to anything that mechanically deforms tissue where receptors are found; mechanically gated ion channels allow for sensory transduction from vibration, light

touch, stretch, and pressure

Thermoreceptors

exteroceptors, most of which are slowly adapting receptors; depolarize in response to temperature changes; separate receptors detect hot and cold

Chemoreceptors

an be either interceptors or exteroceptors; depolarize in response to binding to specific chemicals (in body fluids or in air); generate a receptor potential as sodium ion channels open

Photoreceptors

special sensory exteroceptors found only in eye; depolarize in response to light

Nociceptors

usually slowly adapting exteroceptors; depolarize in response to noxious stimuli