Lab Practical 2- definitions

nerve

carries signal to and from central nervous system

tract

bundle of axons in central nervous system

white matter

myelinated axons

gray matter

made up of neuron cell bodies, dendrites, and unmyelinated axons

neural tissue

forms the brain, spinal cord and nerves

neurons

receive stimuli and transmit electrical impulses

neuroglia

smaller cells that provide support functions for neurons

Astrocytes

What specific type of neuroglia could be found in the spinal cord slide?

central nervous system

brain and spinal cord

peripheral nervous system

bundles of axons called nerves that are connected to the CNS

Cerebellum

important in coordinating movement

arbor vitae

“tree of life”, these tracts carry information to and from the cerebellum

Hypothalamus

inferior to the thalamus

pineal gland

posterior to the thalamus

infundibulum

connects the pituitary gland to the hypothalamus

pituitary gland

small endocrine gland at the base of the brain that is controlled by the hypothalamus and secretes hormones important for fluid balance, growth, and metabolism

cerebral peduncles

visible large columns of white matter in the midbrain

medulla oblongata

most inferior portion of the brainstem; connects to the spinal cord

sella turcica

“turkish saddle”; hold the pituitary gland

foramen magnum

exit for the spinal cord

crista galli

where the dura mater attaches

cribriform plate

allows olfactory nerves to travel through the tiny holes in the plate

perpendicular plate

forms part of the nasal septum

what is on the outside of the spinal cord that contains tracts

white matter

the inside of the spinal cord that contains neuron cell bodies

gray matter

musculocutaneous nerve

muscles of anterior arm

median nerve

muscles of anterior forearm and hand; skin of lateral palm and digits

ulnar nerve

muscles of anterior forearm and hand; skin of medial palm and digits

radial nerve

muscles and skin of posterior arm, forearm and hand

femoral nerve

muscles of anterior thigh

obturator nerve

muscles of medial thigh

sciatic nerve

divides into tibial nerve and common fibular nerve

tibial nerve

supplies muscles of posterior thigh and leg

common fibular nerve

divides into superficial fibular nerve and deep fibular nerve

superficial fibular nerve

muscles of lateral leg

deep fibular nerve

muscles of anterior leg

reflex

automatic, involuntary physical response to a stimulus that occurs without concious thought

mechanoreceptors

detect mechanical forces, pressure, touch, vibration, and stretching

tactile receptors

detect sensations on the skin, light touch, texture, pressure, and vibration

proprioceptors

detect the position and movement of your body parts, including muscle stretch and joint position

thermoreceptors

detect temperature

nociceptors

detect potentially harmful stimuli that can cause tissue damage, producing pain sensations

chemoreceptors

detect chemicals, such as those involved in taste and smell

stretch reflexes

occur when a muscle and its connected tendon are stretched

examples of stretch reflexes

patellar reflex and achillies reflex

patellar reflex

taping the patellar ligament with the reflex hammer and observe the response; monosynaptic

achilles reflex

the tester slightly left the toes toward the shin to make a L and taps the achilles tendon with the reflex hammer; the muscles should have contracted

withdrawal reflexes

occur less frequently to guard against injury; rapidly pulling a limg away when touching something hot; polysynaptic

withdrawal reflex involving the knee

quadriceps- inhibited; hamstrings-contract

cross-extension reflex

neural signals that cross the spinal cord to involve the contralateral limb

superficial cord reflexes

requires the reflex arc in the spinal cord and ascending and descending tracts to the brain to be intact

example of the superficial cord reflex

plantar reflex

negative Babinski sign

when the sole of the foot is stroked, the toes should curl

positive Babinski sign

an abnormal response produces extension of the big toe and spreading of the other toes

positive Babinski sign in infants

this is normal for infants because their spinal cord isn’s fully developed

positive Babinski sign in adults

abnormal; causes a upper motor neuron disorder

cranial nerve reflexes

the sensory and motor neurons are cranial nerves

corneal reflex

mediated by the trigeminal and facial nerves; its absence can indicate damage to the brainstem

autonomic reflex

rely on cranial nerves, but typically have smooth muscle as the effector

pupillary light reflex

controls the amount of light that gets into your eyes to protect the retina

fingertip

highest tactile receptor density

ankle

lowest tactile receptor density

adaptation

ability of some receptors to decrease their firing rate during a prolonged stimulus

touch and temperature receptors

examples that undergo adaptation

optic disc

where the axons of the optic nerve gather; lacks photoreceptors “blindshot”

refraction

bending of light

rods

differentiate light and dark

cones

detect and determine color

semicircular canals

respond to rotation

utricle and saccule

gravity and linear acceleration

near point accomodation

the closest distance at which you can focus clearly

visual acuity

clarity or sharpness of vision and is reported as a pair of numbers; the first number refers to how close you are standing to see it clearly, and the second number refers to how close someone with normal vision had to be to see the same object

astigmatism

focusing is impaired if there are irregularities in the curvature of the lens or cornea

rhodopsin

the pigment can change shape and trigger the rod to send a signal to the CNS, and the pigment detaches from the protein in a process called bleaching

air-conduction hearing

sound travels through the air in your ear canal

bone conduction

sound vibrations travel through the bones of your skull directly to the cochlea, bypassing the outer and middle ear

conductive deafness

a problem in the outer or middle ear

sensorineural deafness

a problem in the cochlea or auditory pathways of the CNS or PNS

vertigo

perception of rotation in the absence of movement or after movement has ceased

nystagmus

the eyes move rapidly to one side then slowly drift back to the center