BIOL2140 Exam 4 Study Guide

peripheral nervous system

provides links from and to the world outside the body and innervates all neural structures outside of the brain. responsible for sensation and perception occurring in the brain

sensory receptors, cranial nerves, peripheral nerves, efferent motor endings

what neural structures outside of the brain are associated with the peripheral nervous system?

type of stimulus, location in body, structural complexity

Sensory receptors are classified based on:

mechanoreceptors

sensory receptors that respond to touch, pressure, vibration, and stretch

thermoreceptors

sensory receptors sensitive to changes in temperature

photoreceptors

sensory receptors that respond to light energy

chemoreceptors

sensory receptors that respond to chemicals

nociceptors

sensory receptors sensitive to pain causing stimuli

exteroceptors

sensory receptors that respond to stimuli arising outside the body; receptors in skin for touch, pressure, pain, temperature, and found in most special sense organs

interoceptors

also called visceroceptors; sensory receptors that respond to stimuli arising in internal viscera and blood vessels; sensitive to chemical changes, tissue stretch, and temperature changes. they sometimes cause discomfort but are usually imperceptible

proprioceptors

sensory receptors responding to stretch in skeletal muscles, tendons, joints, ligaments, and connective tissue coverings of bones and muscles; inform the brain of body movements

Nonencapsulated sensory receptors

sensory receptors without connective tissue sheaths

encapsulated sensory receptors

sensory receptors enclosed in connective tissue sheaths

sensation

the awareness of changes in the internal and external environment

perception

the conscious interpretation of perceived stimuli

receptor level, circuit level, perceptual level

levels of neural integration in sensory systems

circuit level

second level of neural integration in sensory systems which involves processing in ascending pathways

perceptual level

third level of neural integration in sensory systems which involves processing in cortical sensory areas

receptor level

first level of neural integration in sensory systems which involves sensory reception and transmission to CNS

Visceral pain

a consequence of stimulation of visceral organ receptors (by tissue stretching, ischemia, chemicals, or muscle spasms) felt as vague aching, gnawing, or burning

referred pain

pain from one body region perceived from a different body region; visceral and somatic pain fibers travel in the same nerves and the brain assumes stimulus is from a common somatic region

phantom limb pain

sensation of pain that feels like it coming from a limb that has been amputated; due to the spinal cord “learning” the pain of the loss called hyperalgesia

nerves and ganglia

PNS consists of __________________________ outside the central nervous system

nerve

bundle of neuron fibers

endoneurium

connective tissue surrounding each neuron fiber

perineurium

connective tissue covering that bind groups of nerve fibers into fascicles

epineurium

connective tissue covering that binds groups of fascicles together

mixed nerves

nerves containing both sensory and motor fibers

sensory nerves

also called afferent nerves; nerves that carry impulses toward the CNS

motor nerves

also called efferent nerves; nerves carry impulses away from the CNS

somatic afferent, somatic efferent, visceral afferent, visceral efferent

four types of fibers found in mixed nerves

cranial or spinal

peripheral nerves are classified as ____________________ nerves

ganglia

cell bodies associated with nerves in the PNS

cell bodies of sensory neurons

ganglia associated with afferent nerve fibers contain:

autonomic motor neurons

ganglia associated with efferent nerve fibers contain:

vagus nerve

12 pairs of cranial nerves mostly serve head and neck only, except the _______________, which extends to the thoracic and abdominal cavities

spinal cord

spinal nerves are formed by the combination of the ventral and dorsal roots of the:

ramus

branch of a spinal nerve containing both motor and sensory fibers

dorsal rami

branches of spinal nerves that serve the skin and muscles of the posterior trunk

ventral rami

branches of spinal nerves that form a complex of networks called plexuses of the anterior trunk

cervical plexus, brachial plexus, lumbar plexus, sacral plexus

Name the four nerve plexuses of the body

intercostal nerves

ventral rami of T1-T12 that supply muscles of ribs, anterolateral thorax, and abdominal walls

cervical plexus

formed by ventral rami of C1-C4; most of its branches form cutaneous nerves that innervate the skin of neck, ear, back of head, and shoulders

phrenic nerve

major motor and sensory nerve of diaphragm that receives fibers from C3-C5

brachial plexus

formed by ventral rami of C5-C8 and T1; gives rise to nerves that innervate upper limb

roots, trunks, divisions, cord

major branches of brachial plexus

axillary nerve

innervates deltoid, teres minor, and skin and joint capsule of shoulder

musculocutaneous nerve

innervates biceps brachii and brachialis, coracobrachialis, and skin of lateral forearm

median nerve

innervates skin, most flexors, forearm pronators, wrist and finger flexors, thumb opposition muscles

ulnar nerve

supplies flexor carpi ulnaris, part of flexor digitorum profundus, most intrinsic hand muscles, skin of medial aspect of hand, wrist/finger flexion

radial nerve

innvervates essentially all extensor muscles, supinators, and posterior skin of limb

lumbar plexus

arises from L1-L4, innervates thigh, abdominal wall, and psoas muscle

femoral nerve

innervates quadriceps and skin of anterior thigh and medial surface of leg

obturator nerve

passes through obturator foramen to innervate adductor muscles

sacral plexus

arises from L4-S4; serves the buttock, lower limb, pelvic structures, and perineum

sciatic nerve

longest and thickest nerve of the body; innervates hamstring muscles, adductor magnus, and most muscles in leg and foot; composed of the tibial and common fibular nerves

superior gluteal nerve

innervates gluteus medius, minimus, and tensor fascia lata

inferior gluteal nerve

innervates gluteus maximus

dermatome

area of skin innervated by cutaneous branches of single spinal nerve

hilton’s law

any nerve serving a muscle that produces movement at a joint also innervates the joint and skin over the joint

cerebellum and basal nuclei

what structures are the ultimate planners and coordinators of complex motor activities?

segmental level

lowest level of motor control; involves the spinal cord and contains central pattern generators

projection level

middle level of motor control involving the motor cortex and brain stem nuclei; conveys instructions to spinal cord motor neurons and sends a copy of that information to higher levels

precommand level

highest level of motor control involving cerebellum and basal nuclei; programs and instructs based on feedback

intrinsic reflex

rapid, involuntary, predictable motor response to stimulus

acquired reflexes

reflexes resulting from practice or repetition (ex: driving")

receptor, sensory neuron, integration center, motor neuron, effector

components of all simple human reflex arcs

neural crest cells

cranial nerves and spinal nerves come from:

flaccid paralysis

damage to lower motor neurons that leads to muscle atrophy

spastic paralysis

damage to upper motor neurons that leads to irregular stimulation due to reflex action

sciatica

pain caused by irritation, compression, or trauma to the sciatic nerve; causes tingling pain, weakness, numbness in the lower back, buttock, and down leg

autonomic nervous system

two neuron system consisting of preganglionic and postganglionic neurons; activates/regulates smooth muscle, cardiac muscle, and glands; divided into two subdivisions, sympathetic and parasympathetic

parasympathetic division

this division of ANS promotes maintenance activities and conserves body energy; controls digestion, diuresis, defecation, blood pressure; AKA “rest and digest” division

sympathetic division

this division of ANS mobilizing the body during activity; also known as the “fight or flight'“ system; manages exercise, excitement, emergency, embarrassment; increases heart rate, sweat, dilates pupils, etc

cephalization

the evolutionary development of the rostral (anterior) portion of CNS; embryonic brain differentiates from initial neural tube into adult brain structures with age

cerebral hemispheres, diencephalon, brain stem, cerebellum

name the four adult brain regions

brain and spinal cord

the central nervous system is composed of the:

spinal cord

central cavity surrounded by gray matter and external white matter composed of myelinated fiber tracts

brain

contains similar pattern of gray and white matter as spinal cord; includes cerebral hemispheres and cerebellum, scattered gray matter nuclei amid white matter called the basal nuclei and outer gray matter called cortex

ependymal cells

ventricles of the brain are lined by _______________, which secrete cerebrospinal fluid from choroid plexuses

interventricular foramen

the lateral ventricles of the brain connect to the third ventricle via the:

cerebral aqueduct

the third ventricle of the brain connects to the central canal of the spinal cord via the:

septum pellucidum

the paired, c-shaped lateral ventricles of the brain are separated anteriorly by a membrane called the:

diencephalon

the third ventricle of the brain is located in the

hindbrain

the fourth ventricle of the brain is located in the:

lateral apertures and median aperture

the fourth ventricle of the hindbrain contains three openings; two__________________ within the side walls, and one ________________ in the roof

subarachnoid space

the lateral and median apertures connect the fourth ventricle to the:

longitudinal fissure

cerebral hemispheres are separated by the:

corpus callosum

connects the right and left cerebral hemispheres to allow communication between the two

transverse cerebral fissure

deep groove separating the cerebrum and cerebellum

central sulcus

groove separating the precentral gyrus of the frontal lobe and the postcentral gyrus of the parietal lobe

parieto-occipital sulcus

groove separating the occipital and parietal lobes

lateral sulcus

groove outlining the temporal lobes

frontal, parietal, occipital, temporal

name the four surface lobes of the cerebrum

cerebral cortex

thin superficial layer of gray matter forming 40% of the brain’s mass; site of the conscious mind, responsible for awareness, sensory perception, voluntary motor initiation, communication, memory storage, and understanding

motor, sensory, association

name the three types of functional areas of the cerebral cortex

voluntary movement

motor areas of the cerebral cortex control:

conscious awareness of sensation

sensory areas of the cerebral cortex control:

integrate diverse information

association areas of the cerebral cortex:

contralateral

each hemisphere of the brain is concerned with the ________________ side of the body, meaning the left hemisphere controls the right side of the body while the right hemisphere controls the left