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
