Lecture exam

Funiculi

transmits info concerning touch and limb position from body to brain

Descending tracts

transmits motor impulses from cerebral cortex through out the body

Ascending tracts

relay peripheral sensory to the brain

Posterior horn

responsible for sensory processing

Anterior horn

sends motor impulse out to skeletal muscles

Cauda equina

provide motor and sensory function to legs and bladder

Filum terminale

longitudinal support to the spinal cord

Conus medullaris

influences function of genitals, bladder, legs, bowel

Cervical and Lumbar

holds the circuitry that control upper and lower limbs

Function of Spinal cord

receive and send impulse through spinal nerves to diff parts of the body. Major reflex center

Location of Spinal cord

inside the vertebral column extending from foramen magnum to L2 Vertebra

peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body

peripheral nervous system components

somatic nervous system and autonomic nervous system

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles

autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

sensory receptors

neurons that respond to stimuli and trigger electrical signals

Sensory receptor locations

- Exteroceptors - detect stimuli from outside body
- Interoceptors - detect stimuli from within body

nerve structure

Each axon is surrounded by myelin sheath (Schwann Cells), has endonurium, axon, axon hillock, dendrite

sensory nerve

carries messages toward the brain and spinal cord from a receptor; afferent nerve

motor nerves

Carry messages away from the brain and spinal cord to muscles and organs

mixed nerves

nerves carrying both sensory and motor fibers

What are cranial nerves?

I. Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII. Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII. Hypoglossal

What are spinal nerves?

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
31 pairs of nerves arising from the spinal cord

Spinal Nerve Formation

formed by ventral root and dorsal root
once roots meet the spine becomes a mixed nerve (having both motor and sensory fibers)

spinal roots

a bundle of axons surrounded by connective tissue that occurs in pairs, which fuse and form a spinal nerve

Spinal Rami

-Branches that occur after sensory and motor re-join.
-Dorsal (posterior) Ramus
-Ventral (anterior) ramus
-Sympathetic rami (rami comminucantes)

Plexus

large, interlacing network of nerves

major plexuses

cervical, brachial, lumbar, sacral

cervical plexus

C1-C5, phrenic nerve

brachial plexus

C5-C8, T1, and network of interlacing nerves found in the upper arm area

lumbar plexus

T12-L4, femoral nerve

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy

general senses

temperature, pain, touch, pressure, vibration, proprioception

special senses

vision, hearing, taste, smell, equilibrium

special receptors

eyes, ears, etc.

general receptors

skin, muscles, organs, etc.

gustatory receptors

chemoreceptors on the tongue that respond to chemicals in food, taste buds

olfactory receptors

chemoreceptors in the upper nasal cavity that respons to odor chemicals

5 primary tastes

sweet, sour, salty, bitter, umami

The primary taste receptors on the tongue are called

taste buds

Types of papillae on tongue

filiform, fungiform, foliate, circumvallate

filiform papillae

sharp with no taste buds

fungiform papillae

Mushroom-like protuberances often containing taste buds and located on the sides and tip of the tongue.

foliate papillae

on side walls of tongue

circumvallate papillae

large papillae with taste buds- on back of tongue

taste bud structure

made of 40 - 60 cells, oval body located mainly on the dorsal side of the tongue

sniff to smell things better

Brings more air to the olfactory bulb

primary odors

floral, putrid, camphoraceous, musky, pepperminty, ethereal, and pungent

accessory eye structures

eyebrows, eyelids, conjunctiva, lacrimal apparatus, extrinsic eye muscles

Eyebrows Functions include:

shading the eye and preventing perspiration from reaching the eye

Eyelids (palpebrae)

Protection, Shade eyes for sleep, Spread lubricant, Anchor orbicularis oculi

conjuctiva

the mucous membrane that covers the front of the eye and lines the inside of the eyelids.

lacrimal apparatus

the structures that produce, store, and remove tears

extrinsic eye muscles

superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique. Move eyeballs

Eye Tunics

fibrous, vascular, nervous, sclera, choroid, retina

fibrous tunic (sclera and cornea)

The outermost fibrous tunic is a protective layer composed of dense avascular connective tissue. It has two different regions...

-The opaque white sclera forms the posterior 5/6 of the tunic. Provides shape and an anchor for eye muscles

-The anterior-most portion is the transparent cornea, through which light enters the eye.

-The junction between the cornea and sclera is called the limbus.

vascular tunic (uvea)

middle layer of the eyeball composed of the choroid, ciliary body, and iris

nervous tunic (retina)

Innermost layer
I.) Pigmented part
II.) Neural part
lines the posterior two-thirds of the eye. Since a significant portion of the retina is made up of nerve fibers that carry light impulses to the optic nerve it has been described as an extension of the brain

Chambers of the eye

Anterior chamber, posterior chamber, vitreous chamber

aqueous humor

fluid in the eye, found between the cornea and the lens

vitreous humor

the transparent jellylike tissue filling the eyeball behind the lens.

draining of aqueous humor

scleral venous sinus (canal of Schlemm)

Pathway of light to retina

external light-\> cornea-\> aqueous humor-\> lens-\> vitreous body-\> retina

Focusing Light on the Retina near sighted

Myopia

Focusing Light on the Retina far sighted

Hyperopia

far point of vision

point at which lens does not have to thicken to focus. 20 feet or more from eye.

near point of vision

closest point on which the eye can focus

Myopia (nearsightedness)

occurs when the image is focused in front of the retina

Hyperopia (farsightedness)

occurs when the image is focused behind the retina

emmetropia

normal vision

astigmatism

defective curvature of the cornea or lens of the eye

Rod cells

work best in dim light and enable you to see black, white, and shades of gray

cone cells

work best in bright light and enable you to see colors

photopigments

chemicals in photoreceptors that respond to light and assist in converting light into neural activity

dark adaptation

The process in which the eyes become more sensitive to light in low illumination.

light adaptation

the recovery of the eye's sensitivity to visual stimuli in light after exposure to darkness

Glaucoma

increased intraocular pressure results in damage to the retina and optic nerve with loss of vision

cataract

clouding of the lens of the eye

blind spot (optic disc)

where the optic nerve leaves the eye; there are no photoreceptor cells here

convergence of eyeballs

medial rotation of the eyeballs toward the object being viewed

binocular vision

the ability to focus the two eyes in a coordinated manner in order to see one image

bleaching of photopigment

trans-retinal completely separates from opsin. The final products look colorless

outer ear (pinna)

collects sound from air and directs it through the ear canal

outer ear structures

1. Pinna or auricle 2. External auditory meatus/canal 3. Tympanic membrane

middle ear

the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window

middle ear function

amplifies sound

inner ear (labyrinth)

bony spaces within the temporal bone of the skull that contain the cochlea, the semicircular canals, and vestibule. The cochlea facilitates hearing. The semicircular canals and vestibule facilitate equilibrium and balance

inner ear function

hearing and balance

bony labyrinth

winding tunnels located in the inner ear, filled with perilymph

membranous labyrinth

filled with endolymph, membrane-covered tubes inside the bony labyrinth

static equilibrium receptors

maculae, provide information about body position relative to the force of gravity

dynamic equilibrium receptors

crista ampullaris, provide information about body position in response to sudden movement such as rotation, acceleration, and deceleration

otitis media

inflammation of the middle ear

middle ear muscles

tensor tympani and stapedius

tensor tympani

the muscle attached to the malleus; tensing the tensor tympani decreases vibration

stapedius

the muscle attached to the stapes; tensing the stapedius decreases vibration

pathway of sound waves

pinna--\> auditory canal--\>tympanic membrane--\>ossicles--\>oval window--\>cochlea--\>hair cells--\>auditory nerve--\>brain

vertigo

Condition of dizziness, "room spinning", loss of balance

motion sickness

Effect when visual and/or motor feedback is inconsistent with vestibular info