chapter 13: somatic nervous system

the PNS

what is the somatic nervous system a part of?

voluntary (of conscious control)

what does somatic mean?

stimulus

a change in either the internal or external environment

sensation (perception)

a conscious awareness (stimulus triggering receptor)

adaptation

the decrease in a receptors' sensitivity to a stimulus (at the receptor level) ex: smell of your house OR cold pools

habituation

reduced perception of a continuous stimulus (at the brain level/brain's awareness)

transduction

the process of sensory receptors converting a stimulus into an action potential

receptor potentials

what are graded potentials?

stimulus, action potential

receptor potentials-

-their magnitude varies with the strength of the ______

-if the receptor potential reaches threshold the neuron will fire an ____

sensory receptor distribution, stimulus origin, modality

what are the three criteria used to describe receptors?

general and the 5 special senses

what two types of senses fall under sensory receptor distribution?

general senses

type of sensory receptor distribution- distributed throughout the body

temperature, pain, touch, pressure, and proprioception

what are the 5 general senses?

somatic or visceral

general senses can be either what or what?

somatic senses

type of general sense that comes from external stimuli

visceral senses

type of general sense that comes from internal stimuli (organs)

stimulus origin

receptors that detect

exteroceptor and interoceptor

what are the 2 receptors that detect called?

exteroceptor

stimuli from the external environment, such as skin sensation

interoceptor

stimuli from internal organs, such as smooth muscle stretch receptors

modality

the cause of the stimulus

chemoreceptors

receptors that detect chemicals dissolved in fluid, such as ingested food and drink, body fluids, and inhaled air components

chemoreceptors

receptors that are helpful to detect taste, smell, and sodium and glucose levels

thermoreceptors

receptors that are located in the skin and hypothalamus and respond to temperature changes

photoreceptors

receptors that are located in the eyes that detect changes in light intensity, color, and movement

mechanoreceptors

receptors that respond to touch, pressure, vibration, and stretch

movement

mechano means what?

nociceptors

receptors that detect pain

proprioceptors

receptors that detect limb movement, skeletal muscle stretch, and contraction; found in the muscles, tendons, and joints

special sense

what is the receptor distribution of auditory receptors?

exteroceptor

what is the stimulus origin of auditory receptors?

mechanoreceptor

what is the modality of stimulus of auditory receptors?

general sense AND visceral (coming from internal body)

what is the receptor distribution of sodium receptors?

interoceptor

what is the stimulus origin of sodium receptors?

chemoreceptor

what is the modality of stimulus of sodium receptors?

free nerve endings

when dendrites themselves act as receptors it is called what?

encapsulated nerve endings

when sensory nerve endings are wrapped in connective tissue that enhances their sensitivity

olfaction

the special sense known as smell

olfactory epithelium

what is the organ of olfactory?

olfactory receptor cells, supporting cells, and basal cells

what are the cells of the olfactory epithelium?

olfactory receptor cells

a cell of the olfactory- job is to detect odorants (stimulus/chemicals in the air)

olfactory hairs

a cell of the olfactory, but more specifically an olfactory receptor cell- dramatically increases surface area for detecting odorants/bind to them

supporting cells

a cell of the olfactory- ciliated cells that move the mucus and support and protect olfactory receptors

basal cells

a cell of the olfactory- closest to the basement membrane; stem cells meant to replace damaged cells

epithelium

olfaction is deep to the what?

connective tissue

epithelium typically sits on what?

lamina propria

connective tissue underlying a mucous membrane and contains bowman's glands

bowman's glands

These are mucus glands found in the lamina propria that moisten olfactory epithelium and dissolve odor molecules.

chemoreceptors, odorants

olfaction relies on _____ to detect _____

cranial nerve I

what is the olfactory nerve?

olfactory foramina, ethmoid, olfactory bulb, olfactory tract

neurons of the olfactory nerve pass through the _____ ______ in the _____ bone. they then join with the _____ ______, which leads to the _____ _____

frontal lobe, primary olfactory cortex, limbic system

in olfaction- action potentials are sent to what 3 specific regions of the brain?

decision making, emotions

in olfaction- action potentials are sent to the frontal lobe because it is involved in _____ ______ and the limbic system because smell is tied to ______

gustation

what is the special sense known as taste?

lingual papillae

bumps on the tongue that MAY contain taste buds and help to manipulate food

filliform

what are the only lingual papillae with no tastebuds?

receptors, supporting cells, basal cells

what are taste buds made up of?

gustatory receptor cells

part of gustation- receptors that detect chemicals

tastants

what is the chemical called for gustation (like odorants for olfaction)

gustatory microvilli

part of gustation- help with surface area and are hair cells that project from the receptor cell to the external surface through the taste pore in taste bud

supporting cells

part of gustation- cells between receptor cells

basal cells

part of gustation- stem cells to replace damaged cells

sweet, salty, sour, bitter, umami

what are the 5 tastes?

salty

stimulant- presence of sodium ions

sweet

stimulant- presence of sugar/monosaccharides

sour

stimulant- presence of H+ ions (acidic)

bitter

stimulant- presence of OH- ions (basics/alkaloids)

umami

stimulant- presence of L-glutamate

facial, glossopharyngeal, vagus

neurotransmitters from the gustatory receptor cells can activate sensory neurons in what 3 cranial nerves?

temporal lobe

gustatory information is perceived by which lobe in the brain?

olfaction

gustation relies heavily on the sense of what?

increased mucus means less odorants can get to chemoreceptors

what happens to your sense of taste when you have a cold?

bipolar

olfactory receptors are what kind of neurons?

cilia, dendrites

olfactory hairs are ____ and are found on the _____ of olfactory receptor cells

to replace damaged cells

what is the function of basal cells?

action potentials, olfactory

_____ _____ initiated by the protein receptors are carried on the _____ nerve

mucus

bowman glands produce what?

chemoreceptors/chemical

receptors for olfaction and taste rely on what modality of stimulus?

eyebrows, eyelashes

external accessory structures of vision- ____ prevent sweat from dripping into the eye; ____ prevent foreign debris from reaching the eye

palpebra(e)

external accessory structures of vision- superior and inferior eyelids

medial and lateral palpebral commissures

external accessory structures of vision- corners of the eye where palpebrae meet

tarsal glands

external accessory structures of vision- produce oily secretion to reduce friction of palpebrae over eye

lacrimal caruncle

external accessory structures of vision- pink ball in medial commissures that produce secretion to protect eye

4 rectus muscles

extrinsic muscles of vision- superior, inferior, medial, and lateral

2 oblique muscles

extrinsic muscles of vision- superior and inferior; wrap around

oculomotor, trochlear, abducens

remember: the majority of the extrinsic eye muscles are controlled by the _____ nerve (III) while the superior oblique muslce is controlled by the _____ nerve (IV) and the lateral rectus is controlled by the ______ nerve (VI)

ocular and palpebral

internal accessory structures of vision- what are the two types of conjunctiva?

ocular conjunctiva

internal accessory structures of vision- covers the anterior eyeball (not the cornea)

palpebral conjunctiva

internal accessory structures of vision- covers internal surface of eyelids

lacrimal

internal accessory structures of vision- what is the word for tears?

lacrimal apparatus

internal accessory structures of vision- structures that produce, collect, and drain lacrimal fluid

components of tears

internal accessory structures of vision- water, Na+, antibodies, lysozyme (antibiotic enzyme)

lacrimal gland with ducts

internal accessory structures of vision- what produces lacrimal fluid on the lateral side?

lacrimal puncta

internal accessory structures of vision- 2 tiny pores that drain fluid

lacrimal canaliculi

internal accessory structures of vision- 2 tiny canals that transport lacrimal fluid into lacrimal sac

lacrimal sac

internal accessory structures of vision- sac that sits in the lacrimal bone

nasolacrimal duct

internal accessory structures of vision- duct that drains fluid into nasal cavity

fibrous, vascular, and neural tunic

what are the 3 layers of the eyeball?

fibrous tunic

the outermost layer of the eyeball

sclera and cornea

what 2 structures make up the fibrous tunic?