Chapter 13 bold terms

Question 1

Peripheral nervous system (PNS)

Answer 1

Links CNS to body and to external environment

Question 2

Sensory division

Answer 2

Consists of sensory (afferent) neurons that detect and transmit sensory stimuli to CNS; has 2 anatomical subdivisions

Question 3

Somatic sensory division

Answer 3

Detects both internal and external stimuli, detect stimuli from skin

Question 4

Visceral sensory division

Answer 4

Relays information (like blood pressure) from organs of abdominopelvic and thoracic cavaties

Question 5

Motor division

Answer 5

Consists of motor (efferent) neurons; carry out motor functions of nervous system

Question 6

Somatic motor division

Answer 6

Responsible for voluntary motor functions; composed of lower motor neurons (somatic motor neurons), directly trigger skeletal muscle contractions

Question 7

Visceral motor division (autonomic motor nervous system, ANS)

Answer 7

responsible for maintaining many aspects of homeostasis by controlling involuntary motor functions in the body; innervate cardiac muscle cells

Question 8

Sympathetic nervous system (fight or flight division)

Answer 8

involved in homeostasis activities surrounding physical work and visceral responses of emotions

Question 9

Parasympathetic system (rest and digest division)

Answer 9

involved in digestion and maintaining body’s homeostasis at rest

Question 10

Peripheral nerves

Answer 10

Main organs of PNS; consist of axons of many neurons bound together by connective tissue

Question 11

Mixed nerves

Answer 11

Contain both sensory and motor neurons

Question 12

Sensory nerves

Answer 12

Contain only sensory neurons while motor nerves contain mostly motor neurons

Question 13

Spinal nerves

Answer 13

Originate from spinal cord and innervate structures below head and neck

Question 14

Epineurium

Answer 14

outermost layer of connective tissue that holds motor and sensory axons together

Question 15

Fascicles

Answer 15

Small groups of bundled axons surrounded by connective tissue called perineurium

Question 16

Cranial nerves

Answer 16

Attach to brain and mostly innervate structures in head and neck; allows for purely sensory, mixed and mostly motor nerves

Question 17

Spinal nerve

Answer 17

Short and divides into following 2 mixed nerves; both carry both somatic motor and sensory information

Question 18

Posterior ramus

Answer 18

Travels to posterior side of body

Question 19

Anterior ramus

Answer 19

Travels to anterior side of body and/or to an upper or lower limb

Question 20

Hiccups

Answer 20

annoying spasms of diaphragm that cause a forceful inhalation of air

Question 21

Sciatic nerve

Answer 21

longest and largest nerve in body; contains axons from both anterior and posterior divisions of sacral plexus

Question 22

Exteroceptors

Answer 22

usually close to bodys surface; detect stimuli originating from outside body

Question 23

Interoceptors

Answer 23

usually found within bodys interior; detect stimuli originating from within body itself

Question 24

Mechanoreceptors

Answer 24

Depolarize in response to anything that mechanically deforms tissue where receptors are found; mech gated ions allow for sensory transduction (vibration, light touch, stretch, and pressure)

Question 25

Themoreceptors

Answer 25

Exteroceptors, most of which are slowly adapting receptors; depolarize in response to temp change

Question 26

Chemoreceptors

Answer 26

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

Question 27

Photoreceptors

Answer 27

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

Question 28

Nociceptors

Answer 28

Usually slowly adapting exteroceptors; depolarize in response to noxious stimuli

Question 29

Referred pain

Answer 29

Phenomenon whereby pain that originates in an organ is perceived as cutaneous pain

Question 30

Upper motor neurons

Answer 30

neurons of primary motor cortex make decision to move and initiate that movement; but not in contact with muscle fiber itself

Question 31

Lower motor neurons

Answer 31

receive messages from upper motor neurons; in contact with skeletal muscle fibers; release acetylcholine onto muscle fibers to initate contraction

Question 32

Reflexes

Answer 32

Programmed, automatic responses to stimuli; occur in a three-step sequence of events called a reflex arc; usually protective negative feedback loops

Question 33

Monosynaptic reflexes

Answer 33

simplest reflex arcs; involve only a single synapse within spinal cord between a sensory and motor neuron

Question 34

Polysynaptic reflexes

Answer 34

More complicated types of reflex arcs; involve multiple synapses

Question 35

Simple stretch reflex

Answer 35

Bodys reflexive response to stretching of muscle to shorten it back to within its "set" optimal length

Question 36

Simple stretch reflexes

Answer 36

Patellar reflex and jaw jerk reflex

Question 37

Golgi tendon reflexes

Answer 37

polysynaptic reflexes; protect muscles and tendons from damaging forces

Question 38

Flexion or withdrawal reflex

Answer 38

Involves rapidly conducting nociceptive afferents and multiple synapses in spinal cord; act to withdraw limb from painful stimuli

Question 39

Crossed extension reflex

Answer 39

Occurs simultaneously on opposite side of body for balance and postural support while other limb is withdrawn from a painful stimulus

Question 40

Cranial nerve reflexes

Answer 40

Polysynaptic reflex arcs that involve cranial nerves

Question 41

Gag reflex

Answer 41

Triggered when visceral sensory nerve endings of glossopharyngeal nerve in posterior throat are stimulated

Question 42

Corneal blink reflex

Answer 42

triggered when a stimulus reaches somatic sensory receptors of trigeminal nerve in thin outer covering of eye (cornea); something contacts eye leading to a blink response

Question 43

Amyotrophic lateral scelrosis (ALS) or Lou Gehrig's disease

Answer 43

Involves degeneration of cell as well as upper motor neurons in cerebral cortex; cause of degeneration is unknown at present