Lab Exam 2:

frontal lobe (pre central gyrus), parietal lobe (post central gyrus), temporal lobe, occipital lobe, and insula

cerebral cortex contains

Frontal Lobe

Responsible for voluntary motor control, personality, intellectual processing, and verbal communication.

Pre-Central Gyrus

Area of the brain responsible for conscious motor control.

Parietal Lobe

Involved in understanding words and formulating words to express thoughts.

Post Central Gyrus

Somatosensory cortex; processes sensation from skin, joints, muscles, and tendons.

Temporal Lobe

The hearing center of the brain.

Occipital Lobe

The visual center of the brain.

Insula

Involved in processing visceral sensations and keeping them in memory. (example: food poisoning results in never eating that food or at that restaurant again)

Cerebellum

Responsible for posture, balance, and smooths and directs movement. (example: walk white line, touch finger to nose, drunk driving test)

thalamus and hypothalamus

Diencephalon contains

Thalamus

Relay station for all sensory information except smell as it passes to the cerebrum.

Hypothalamus

Control center for hunger, thirst, body temperature, and hormone secretion.

midbrain, pons, medulla oblongata

brainstem contains

Midbrain

Relay center for auditory information, motor coordination, reward behavior

Pons

Responsible for respiratory control.

Medulla Oblongata

Controls respiratory, vasomotor, and cardiac functions.

gray horns, white columns, dorsal root and dorsal root ganglia, ventral root, spinal nerve

spinal cord contains

Gray Horns

Contains sensory neuron axon terminals, interneurons, and motor neuron cell bodies.

White Columns

Contain myelinated axons of interneurons.

Dorsal Root

Contains myelinated axons of sensory neurons.

Dorsal Root Ganglia

Contains cell bodies of sensory neurons.

Ventral Root

Contains myelinated axons of motor neurons.

Spinal Nerve

Contains myelinated axons of both sensory and motor neurons.

dendrite, cell body, axon

neuron contains

Dendrite

Site of graded potential generation in a neuron.

Cell Body

Site of graded potential generation and integration of incoming signals.

Axon

Responsible for the propagation of action potential and release of neurotransmitters.

reflex

simple motor response to a particular stimulus that occurs not under conscious control

Specific simple reflex arcs are associated with specific spinal cord segments, making tests for reflexes useful in diagnosing neurological disorders

Reflex Clinical Significance

sensor, sensory neuron, interneuron (optional), motor neuron, and effector.

Reflex Arc consists of

Sensory Receptor

receive stimuli (changes in the environment) and change (transduce) incoming signals into action potentials that are sent to specific parts the of the brain for interpretation

sensory neuron

communicates information from PNS to CNS with axon potential

Interneuron

integration, decision maker neuron

motor neuron

extends out of CNS to effector organ

Effector

Muscle or gland that performs the response in a reflex arc.

Knee Jerk Reflex

stretch reflex, that is monosynaptic and involves a sensory receptor that is muscle spindle

Stretch Reflex

Protects muscles from overstretching and aids in postural adjustments.

Muscle Spindles

stretch receptors that respond to changes in muscle length and provides a length detector within muscles

proprioceptive information

stretch reflex provide

Monosynaptic Reflex

Reflex involving a sensory neuron synapsing directly with a motor neuron.

there would be no effect in knee jerk reflex because information does not have to travel to travel to and from the cerebral cortex

if patient has damage to cervical spinal cord, what would occur with knee jerk reflex

Latent Period

Time between the onset of the stimulus and the onset of effector muscle contraction.

number of synapses in a particular pathway

Latent Period reflects -

voluntary latent period was longer, due to neural pathway for voluntary response containing many synapses, taking longer than the reflex response that has only one synapse

when comparing the knee jerk reflex with voluntary response of raising leg

Plantar Reflex

Neurological test elicited by cutaneous receptors on the sole of the foot.

cutaneous sensory receptor in foot transmits information to lumbar region of spinal cord to sensory cortex of the brain, then through the pyramidal motor tracts descending from cerebral cortex to lower motor neurons in the spinal cord

Plantar Reflex pathway

adduction and plantar flexion of toes

plantar reflex normal response

abduction and dorsiflexion of toes

plantar reflex abnormal response

abnormal response infers the patient has damage along the pyramidal motor tract

plantar reflex clinical significance

it would prevent sensory input from reaching the brain and motor output from reaching the foot

if patient has damage to cervical spinal cord, how would it effect plantar reflex

Adaptation

Ability of sensory receptors to reduce signal sent in response to a continued stimulus.

place a coin on forearm and let it remain there, and place a rubber band around head and see which adaptation occurs faster - sensation of the coin adapted quicker

testing adaptation

Law of Specific Nerve Energies

sensation produced by the “adequate” stimulus (normal stimulus) is the one the brain will perceive, even if the stimulus is different than normal nature

adequate stimulus

type of stimulus to which the receptor is most sensitive to

bright light and color

adequate stimulus for cones of the retina

sound waves

adequate stimulus for hair cells of cochlea

deep pressure

adequate stimulus for Pacinian corpuscles

light touch

adequate stimulus for Meissner’s corpuscles

pressing on the eye creates a sensation of light ("seeing stars") because the optic nerve is activated, even though the stimulus was physical pressure, not light.

Testing Law of Specific Nerve Energies

when placing gloved hand into beaker of water, hand remains dry but sensation of wetness is felt due to sensation of temperature and pressure

testing perception

Acuity

Ability of sensory receptors to discriminate between two different points of stimulation.

Receptor Fields

Area of skin associated with a single sensory receptor.

inversely

density of sensory receptors/receptor size are ______ related to the size of somatosensory cortex devoted to a specific body part

Two-Point Discrimination Test

Measures the minimum distance at which two points can be felt as separate.

Vestibular Apparatus

Part of the inner ear responsible for equilibrium, including utricle, saccule and semicircular canals

Cochlea

Part of the inner ear responsible for hearing; converts sound vibrations to neural signals.

Bony Labyrinths

contain the membranous labyrinths within a body cavity, filled with fluid (perilymph)

membranous labyrinths

tubular structure within the bony labyrinth that contains fluid (endolymph)

Hair Cells

Type of mechanoreceptor that depolarizes based on mechanical deformation.

Conduction Deafness

Caused by damage in the middle ear affecting sound transmission.

Sensory Deafness

Resulting from damage to the cochlea or vestibulocochlear nerve.

Conduction Deafness

strike tuning fork and place handle on mastoid process behind ear then placing it in front of ear. if patient does not hear sound when placed next to external auditory canal, the patient has

vibrating skull bone makes fluid in cochlea move, causing basilar membrane move, bending stereocilia into tectorial membrane, creating actions potential that are sent to auditory cortex

how does striking a tuning fork and putting it on mastoid process still transmit sound

conductive deafness because damaged ear is more upregulated (sensitive to sound) relative to normal ear

strike tuning fork and place base at center of forehead. if sound is louder in damaged ear, indicates

sensory deafness because cochlea in damaged ear has diminished ability to generate action potentials

strike tuning fork and place base at center of forehead. if sound is louder in non-damaged ear, indicates

utricle, saccule, macula and otoliths

vestibule consists of

utricle

senses horizontal acceleration

saccule

senses vertical acceleration

macula

hair cells with stereocilia that embedded in a gelatinous otolithic membrane in the vestibule

otoliths

crystals of calcium carbonate that weigh down the gelatinous otolithic membrane

semicircular canal

detect angular or horizontal acceleration

crista ampullaris

where sensory hair cells are located in semicircular canal

cupula

a gelatinous structure that extends over the crista ampullaris, involved in the detection of rotational movements.

cerebellum and vestibular nuclei (in brain stem)

neural pathway for equilibrium and balance (integration center for vestibular apparatus)

tympanic membrane (ear drum)

detects vibrations, moves in concert with the vibrations

ossicles (malleus, incus, and stapes):

amplify vibrations

oval window

entrance into the cochlea

organ of corti (spiral organ):

sits on the basilar membrane in the cochlear duct, containing hair cells and stereocilia

auditory cortex of the temporal lobe

Neural Pathways of Hearing

Photoreceptors

stimulated by electromagnetic radiation

cornea

focus light onto retina

pupil

opening for light to go through

iris

regulate size of pupil

post ganglionic sympathetic neuron

what causes dilation of pupil in dim light

post ganglionic parasympathetic neuron

what causes constriction of the pupil in bright light

lens

provides accommodation

ciliary muscle relaxes, causes tension of lens making it thinner

seeing far is allowed when

when ciliary muscle contracts, causes lens to get bulgy

seeing close is allowed when

visual acuity

the sharpness of vision, the power to discriminate details

Emmetropia

normal vision, rays focus on retina