Nervous System Flashcards
Afferent, or sensory nerves are?
Nerves that relay sensory information from periphery to CNS
Efferent, or motor nerves are?
Nerves that send information from CNS to peripheral effector cells & organs
Name the 2 components of the efferent (motor) nervous system.
Somatic ns -supply skeletal muscle & regulate contraction
Autonomic ns -innervates & regulates non-motor organs (involuntary stuff).
Name the 3 kinds of receptors in the afferent sensory system
exteroception (external)
Interoception (internal)
Proprioception (position & movement of body)
Receptors do not?
interpret stimuli. they are transducers that receive stimuli & generate a nerve impulse
Name the 5 classifications of receptors
Mechanoreceptors Thermoreceptors Nociceptors (potentially injurous stimuli) Photoreceptors Chemoceptors (MOST PRIMITIVE SENSE)
Name the 4 things involved in proprioception
joint receptors -info on tension & pressure
muscle spindles -changes in muscle length
golgi tendon organs -tension in tendons
skin mechanoreceptors -contact w/ enviro
Describe visceral sensation
involves structures in body cavity
not available to consciousness
autonomic activity
Describe how ‘smelling’ works
odorants pass into nose
dissolve in mucus in nose
bind w/ chemoreceptors
Describe the location of olfactory organs and what they consist of
Located on either side of nasal septum
consisting of: supporting cells (Bowman’s glands) =>secrete mucous, olfactory receptor cells, basal cells
a bit about olfactory bulbs?
each is lined w/ layer of glomeruli
each glomerulus receives info from only 1 type of olfactory receptor, & olfactory nerve synapses w/ mitral cells which send info about odours to limbic system & brain
Describe taste buds and their location
located in tongue/throat. Not evenly distributed, lie along walls of papillae (elevations in tongue). End in microvilli which bear receptor proteins.
5 types: sweet, sour, salty, bitter, umani (aa)
LEARN TO LABEL EYE DIAGRAM
DO IT.
The retina contains what?
rods and cones
A bit about rods
detect light & dark, black & white vision
Contain 1 photopigment, rhodopsin
A bit about cones
detect colour
require more light to be activated
Not present in fovea
contain 3 photopigments sensitive to blue, red or green
What are bipolar cells (in eye)?
intermediary cells that transmit electrical signals from rods & cones to ganglion cells
What are ganglion cells?
cell bodies of optic nerve =>connect to CNS
Describe dark phototransduction, and what structure carries this out
Rods.
When light transmits through eye, rhodopsin in discs absorbs light, causing it to dissociate into retinene & opsin components.
Leads to reactions & closure of ion channels in rod plasma membrane.
Optic nerve transmits electrical signal to brain
Describe light phototransduction, and what structure carries this out
Cones.
Light absorbed by photopigment (red, green or blue).
Results in colour image.
Describe how an image is created in the eye
light strikes photoreceptor, AP conducted to optic nerve.
Axon then pass through optic chiasma & become part of optic tract
axons enter brain & terminate in geniculate nucleus of thalamus
geniculate nuclei signal transmitted by new neurons (optic radiations) to visual cortex
Focus of the eye is controlled by?
ciliary muscle (called visual accomodation)
Colour vision occurs in?
some non-primate mammals, birds, reptiles, amphibians, fish & insects
Nocturnal animals have no colour vision
What is the visual field?
part of the environment from which light enters eyes & stimulates retinas
What is the sclera?
connective tissue outer protective layer. connected to cornea
What is the cornea?
outermost transparent layer, allows transmission of light into eye
What is the anterior/posterior chamber?
cavity containing aqueous humor.
beneath cornea (anterior).
underlies iris, overlies lens (posterior)
What is the vitreous chamber?
cavity containing vitreous humor. b/w lens & retina
What is the iris?
smooth muscle that control amount of light entering eye
What is the pupil?
hole in iris which light passes through on way to retina
What is the lens?
biconvex structure responsible for focusing images on retina
What is the ciliary body?
tissue connecting choroid & iris; contains ciliary muscles
What is the choroid?
highly pigmented tissue containing dense network of blood vessels
What is the retina?
innermost layer of eye; contains photoreceptors, fovea & optic disk
What is the optic disk?
area where mulitpolar ganglion cells merge into optic nerve
What is the fovea?
central part of retina, where light from centre of vision if transmitted to
What are zonular fibres?
connect ciliary muscles to lens
LEARN TO LABEL EAR DIAGRAM
DO IT SHITHEAD.
Name the parts of the external ear
Pinna (auricle) aka ear lobes
external auditory meatus (ear canal)
What is the tympanic membrane? And what does it separate?
Ear drum. Separates external ear from middle ear
what is the function of the middle ear? Name the parts it contains.
To amplify soundwaves transmitted to tympanic membrane.
3 auditory ossicles: malleus (hammer), incus (anvil), stapes (stirrup).
Span from tympanic membrane to vestibular (oval) window
Name the components of the inner ear and their functions
Inner ear aka labyrinth
Vestibular apparatus receptor for equilibrium, balance & head position. 3 major components:
semicircular canals -detect changes in direction
utricle & saccule -U is for balance, S is for hearing
Cochlea -fluid filled spiral housing organ of corti
Describe the process of hearing
sound waves funnelled into external auditory meatus by pinna to tympanic membrane (TM)
sound waves hit TM causing it to vibrate
Vibrations of TM induce vibrations in middle ear ossicles
Once vibrations reach oval window, basilar membrane moves fluid of cochlea (perilymph).
Distorted hairs then generate AP to auditory nerve =>brain.
Somatic motor neurons do what? (think coordination)
stimulate muscles to cause muscle contraction
Central Pattern Generators (CPG) are located where and control what?
Located in spinal cord.
Control limb coordination, rhythm, speed
A bit about Upper & Lower motor neurons
UMN regulate LMN activity.
UMN -initial voluntary movement, maintain stable body posture & position
Final common pathway for all movement is via LMN
