LECTURE EXAM 1

SNS vs ANS

SNS: voluntary movements, primarily acetylcholine, involves one motor neuron from CNS to effector
ANS: involuntary movements, primarily acetylcholine and norepinephrine, involves two neurons- preganglionic and postganglionic

primary neurotransmitter in the somatic nervous system

acetylcholine

the somatic nervous system controls ______ movements

voluntary

what is the role of acetylcholine in the parasympathetic nervous system?

• promotes digestions

• slows heart rate

What is a tendon organ

a specialized sensory receptor located at the junction of a muscle and its tendon that monitors muscle tension

in the sympathetic nervous system, acetylcholine is released from…

preganglionic cells

what is the role of acetylcholine in the somatic nervous system

stimulates skeletal muscle contraction by binding to nicotinic receptors on muscle fibers; found at neuromuscular junctions

what is the role of acetylcholine when it comes to special senses

filters/prioritizes sensory information

role of acetylcholine in sensory pathways

enhances relay and perception of sensory signals

role of acetylcholine in motor integration

helps with fine motor coordination and timing

the autonomic nervous system primarily controls _______ movements

involuntary

subsets of the ANS

• sympathetic

• parasympathetic

primary autonomic nervous system neurotransmitters

acetylcholine and norepinephrine

interneuron

neuron in the CNS that connects sensory neurons and motor neurons

nociceptor

specialized sensory receptor that detects harmful/potentially damaging stimuli and sends pain signals to the CNS

cerebral neurons

specialized nerve cells in the cerebrum, responsible for allowing us to think, feel, and act via chemical/electrical signals

umami

savory/meaty taste caused by glutamate

function of the choroid

• supplies oxygen and nutrients to the outer retina

• absorb stray light to reduce visual distortion

• maintains visual clarity

choroid

vascular, pigmented layer of the eye located between the retina and the sclera

ophthalmoscope

medical instrument used to examine the interior of the eye, especially the retina, optic disc, macula, and blood vessels

astigmatism

condition in which the cornea/lens has an irregular curve, preventing light rays from focusing evenly on the retina, leading to blurry/distorted vision

supporting cells

specialized cells that surround, nourish, protect, and maintain the function of primary cells without conducting nerve impulses themselves

otoliths

tiny calcium carbonate crystals found in the inner ear; plays a critical role in balance, spatial orientation, and motion

preganglionic neuron

the first neuron in a two-neuron pathway of the autonomic nervous system

postganglionic neurons release…

norepinephrine & acetylcholine

preganglionic neurons releases…

acetylcholine

role of norepinephrine in the sympathetic nervous system

• increases HR

• increases BP

• dilates pupils

• slows digestion

• triggers flight/fight response

role of norepinephrine in the brain

• enhances alertness

• increases focus/attention

• mood regulation

norepinephrine

neurotransmitter and hormone that plays a role in the autonomic nervous system, brain, and endocrine system

sensation

process in which sensory receptors detect changes in the internal or external environment and transmit this information to the brain/spinal cord for processing

thermoreceptor

type of sensory receptor that detects changes in temperature

olfaction

sense of smell

papillae

small, visible projections/bumps on the tongue that aid in taste, texture detection, and food manipulation

vascular tunic

the middle layer of the eyeball; consists of the choroid, ciliary body, and iris

the optic disc is also known as the…

blind spot

optic disc

structure in the retina where visual information exits the eye and heads toward the brain; where the optic nerve begins

rhodopsin

a light-sensitive photopigment found in the rods of the retina; plays a key role in low light vision

true or false: rods can detect color

false

rods

one of the two main types of photoreceptor cells in the retina of the eye; highly sensitive to light and allow us to see in dim (night) lighting

proprioception

the body's sense of its own position, movement, and location in space

geniculate nuclei

structure in the brain that relays visual information from the retina to the visual cortex

postganglionic neuron

the second motor neuron in the autonomic nervous system pathway

autonomic reflex

an involuntary, rapid, and automatic response mediated by the autonomic nervous system

perception

conscious interpretation, organization and awareness of sensory information processed by the brain, turning raw sensory input into meaningful experiences

lower motor neurons

neurons that directly innervate skeletal muscles, causing them to contract and produce voluntary movement

bowman’s gland

specialized mucus-secreting glands located in the olfactory mucosa of the nasal cavity; play a role in the sense of smell by dissolving odor molecules

accommodation

process by which the lens of the eye changes shape to focus on objects at different distances; allows us to shift our focus between near and far objects

scala vestibuli

the upper chamber of the cochlea, filled with perilymph; plays a key role in the process of hearing by transmitting sound vibrations from the oval window to the cochlear duct

cones

one of the two types of photoreceptor cells in the retina of the eye; responsible for color vision, sharp visual acuity, and seeing in bright (day) light

sensory neuron

nerve cell that carries information from sensory receptors in the body to the brain/spinal cord for processing

photoreceptor

specialized sensory neurons in the retina of the eye that detect light and convert it into electrical signals for visual processing

spinal nerve

mixed nerve that carries motor and sensory information between the spinal cord and the rest of the body

basal stem cells

undifferentiated cells located in the basal layer of certain epithelial tissues; source of new cells that continuously divide to replace damaged or aged cells and maintain tissue integrity

sclera

the white, tough outer layer of the eye that provides structure, protection, and attachment for the eye muscles

vitreous humor

clear, gel-like substance that fills the vitreous chamber of the eye, helping to maintain the eye’s shape

emmetropic

having normal vision where light focuses perfectly on the retina, resulting in clear, crisp vision without the need for corrective lenses (20/20)

organ of corti

sensory organ of hearing located within the cochlear duct of the inner ear; It contains the hair cells that convert sound vibrations into nerve impulses

binocular vision

ability to use both eyes together to perceive a single, three-dimensional image

static equilibrium

Maintenance of body position relative to gravity

dynamic equilibrium

Maintenance of body position in response to motion

movement of sound waves from the outer ear to inner ear

1. sound collection (outer ear)

2. vibration (tympanic membrane)

3. amplification (middle ear)

4. transmission (inner ear)

5. sensory detection (organ of corti)

6. neural transmission (brain)

components of the middle ear

1. incus

2. malleus

3. stapes

function of auditory tube

equalizes air pressure between the middle ear and the nasopharynx

function of tympanic membrane

thin, flexible membrane that vibrates in response to sound waves from the external auditory canal; separates outer and middle ear

function of stapes

transmits sound vibrations from the incus to the inner ear via the oval window

function of malleus

attaches to the tympanic membrane and transmits sound vibrations to the incus

function of incus

connects malleus to stapes

components of the outer ear

• auricle

• external auditory canal

• ceruminous glands

function of the external auditory canal

transmits sound to the tympanic membrane

function of the auricle

collects sound waves and directs them into the ear canal

function of ceruminous glands

produces/secretes cerumen (earwax) to protect the canal and eardrum

components of the inner ear

1. cochlea

2. semicircular canals

function of cochlea

translates vibrations into neural impulses that the brain can interpret as sound

function of semicircular canals

fluid-filled loops that detect rotational movements of the head; works with the cerebellum for balance and equilibrium

what are the 2 types of photoreceptors

1. rods

2. cones

flow of tears

1. lacrimal glands

2. lacrimal ducts

3. lacrimal canaliculi

4. lacrimal sac

5. nasolacrimal ducts

6. nasal cavity

three types of cells in the olfactory tract

1. Olfactory receptor cells

2. Supporting cells

3. Basal cells

Function of basal cells in olfactory tract

act as stem cells that undergo mitosis to replace old or damaged olfactory receptor cells

Function of supporting cells in olfactory tract

provides structural and metabolic support; secretes enzymes to help break down odorants

Function of olfactory receptor cells

produces mucous that is used to dissolve odor molecules, so transduction may occur

3 types of proprioceptors

1. muscle spindles

2. tendon organs

3. joint kinesthetic receptors

muscle spindles function

monitors muscle length and is involved in stretch reflexes

tendon organs function

monitors muscle tension to regulate muscle contraction and protect against muscle damage from excessive tension/stretching

joint kinesthetic receptors

responds to pressure, acceleration, and deceleration during movement; helps
protect against excessive strain

accessory structures of the eye

• eyelids

• eyelashes

• eyebrows

• lacrimal apparatus

• extrinsic eye muscles

5 steps of the reflex arc

1. sensory receptor

2. sensory neuron

3. integration center

4. motor neuron

5. effector

divisions of the autonomic nervous system

• sympathetic nervous system

• parasympathetic nervous system

sympathetic nervous system function

• prepares the body for emergency situations (flight or fight)

• increases HR, BP, dilates pupils, inhibits digestion

parasympathetic nervous system

• promotes relaxation, digestion

• slows HR

pre ganglionic neurons vs post ganglionic neurons

• pre ganglionic neurons are myelinated, post ganglionic neurons are not

• pre ganglionic neurons always releases Ach, post ganglionic neurons release NE and Ach

functions of upper motor neurons

Initiates, plans, and coordinates voluntary movement

function of lower motor neurons

Executes movement by stimulating muscle contraction

ANS neurotransmitters

1. acetylcholine

2. norepinephrine

3. epinephrine

role of acetylcholine in the ANS

• stimulates smooth muscle

• slows heart rate

• increases digestion

• activates nicotinic/muscarinic receptors

role of norepinephrine in the ANS

• Increases HR & BP

• Dilates pupils

• Slows digestion

• Acts on adrenergic receptors (alpha & beta)

role of epinephrine in the ANS

extends and enhances the “fight or flight” response

cornea

clear outer surface of the eye, bends the light entering the eye

sclera

white part of the eye that protects/maintains its shape

iris

colored part of the eye that controls pupil size to regulate light entry

pupil

central opening in the iris, allows light to enter the eye