NSCI 2001 Midterm 3

University of Minnesota (UMN) NSCI 2001 Human Neuroanatomy midterm 3. Set your settings so that it's answer with definition only or you'll cry :(

p type ganglion cells

• small dendritic arbor

• few bipolar cells

• color and form perception

m type ganglion cells

• large dendritic arbor

• many bipolar cells

• motion perception

fovea

• high acuity vision

• only cones (no rods)

• no blood vessels

optic chiasm

where the optic nerve attaches to the brain. retinal axons from nasal side of retina cross in the chiasm

binocular zone

center of visual field where both eyes see

monocular zone

peripheral vision which goes to only one eye

axons of the nasal side of retina _______ in the optic chiasm and goes on the ______ side to the visual cortex

cross; contralateral

axons of the temporal side of retina _______ in the optic chiasm and goes on the ______ side to the visual cortex

do not cross; ipsilateral

the right visual hemifield from both eyes goes to the ____ side of the brain

left

lateral geniculate nucleus

area in thalamus that processes vision

primary visual cortex (V1)

• located on either side of calcarine sulcus

• receives information from lateral geniculate nucleus (LGN)

suprachismatic nucelus

• hypothalamus

• regulates circadian rhythms

pretectal nucleus

• midbrain

• pupillary light reflex

superior colliculus

• midbrain

• oculomotor control

area 2/4

lateral geniculate nucleus

lateral geniculate nucleus has X cell layers

six

cells from M type ganglion cells synapse here

Layers 1 and 2 of the LGN

cells from p type ganglion cells synapse here

layers 3-6 of LGN

lateral geniculate has this type of organization

retinotopic

meyer’s loop processes fibers from ______ in the ___ lobe, _____ to the calcarine fissure

inferior retina/superior visual field; temporal; inferior

fibers representing the ________ are processed in the ______ lobe, ______ to the the calcarine fissure

superior retina/inferior visual field; parietal; superior

inputs from thalamus synapse in what layer of neocortex

layer 4 of neocortex

layer 4 neurons send axons to

layers 2 and 3 of neocortex

primary visual cortex has three types of columns

1. orientation

2. ocular dominance

3. color

how does the layout of visual information in the columns change during development

begin overlapped but eventually segregate completely

dorsal stream

• motion

• location

• “where pathway”

ventral stream

• color

• object recognition

• “what pathway”

where do visual areas of the cortex from two hemispheres communicate?

corpus callosum

labyrinth/inner ear

• cochlea

• vestibule (utricle and saccule)

• semicircular canals.

cochlea

organ that transduces sound into nerve impulses

semicircular canals

angular acceleration into nerve impulses on x y and z axis

vestibule

utricle and saccule, linear acceleration

utricle

horizontal acceleration

saccule

acceleration in saggital plane (front/back, up/down)

tympanic membrane

ear drum, moves with vibration

external ear

collects sound

ossicles

1. maleus (hammer)

2. incus (anvil)

3. stapes (stirrup)

what cochlea shape ?

tube folded in half and then wound into 2.5 spiral

oval window

movement of stapes causes pressure wave to move down cochlea

round window

where the pressure wave of sound exits the cochlea

basilar membrane

where hair cells sit between the two limbs of tube

hair cells

detect sound and movement with different heights of hairs that get closer or further apart from each other

spiral ganglion

primary afferent neurons for hearing

the basilar membrane is thickest at the _________ and thinnest at the ________

base; apex

highest frequencies are located

closest to the beginning of basilar membrane

lowest frequencies are detected at the?

apex of cochlea

tonographic organization is _____

logarithmic

depolarization hair cell hearing causes

excitation, when hairs get further apart on cell (towards longest hair)

hyperpolarization hair cell hearing causes

inhibition, moves towards shortest hair, closer together

cochlear nuclei

sound localization and identification: medulla

superior olivary nuclei

sound localization and volume control: pons

inferior colliculus

identification of and reflexive responses to sounds: midbrain

medial geniculate nucleus

thalamic relay nucleus for hearing

auditory cortex

tonotropic organization, sound identification

conduction deafness

bone issues or earwax that causes hearing loss

sensorineural deafness

• most common form

• exposure to loud noises or age related

• treated with hearing aids

flocculonodular lobe

where vestibular apparatus projects axons

projections to nuclei innervating extraocular muscles

• track objects while turning your head

• vestibular ocular reflex

projections to spinal cord and cerebellum are responsible for (in balance)

coordinating eye movements with head and neck. coordinate vestibular input with “anti-gravity” muscles

three inputs that tell us how body is oriented

1. proprioception

2. vestibular system

3. vision

Vertigo

sensation of turning in absence of motion

nystagmus

repetitive tracking eye movements in absence of movement

what are the chemical senses?

1. taste (gustation)

2. smell (olfactory)

olfactory epithelium

roof of nasal cavity where smell receptors sit

anterior cribriform plate

small holes where thin axons travel from the nose to the olfactory bulb

olfactory bulb

where axons from the olfactory sensory neurons synapse

____ type of odorant receptors are present per olfactory neurons

1

how long is the lifespan of an olfactory neuron

1-2 months

receptors for smells are similar to ____ neurotransmitter receptors

g-protein coupled

how many odorant receptor types do humans have? how many do mice have ?

350, 1000

how do different specific smells get encoded in the odorant receptors?

odorants are recognized by different combinations of odorant receptors

glomeruli

where different inputs are relayed and modulated in the olfactory bulb, specific to different odors

olfactory cortex

• located in rostral telencephalon

• where the olfactory bulb projects

orbitofrontal cortex

• just above eyes

• allows for odor discrimination

where scent is processed to involve appetite

lateral hypothalamus

pheromones

• in animals (not humans)

• modulate reproductive hormones

• aggression

• often found in urine or glandular secretions

anosmia

• inability to smell

• can be caused by traumatic injury, genetics, and infection

what are the five tastes

1. sweet

2. umami,

3. salt,

4. sour,

5. bitter

which tastes are innately attractive to humans?

1. sweet

2. umami

which tastes are innately aversive to humans

1. sour

2. bitter

taste

results from activation of five receptors

flavor

taste combined with smell and somatosensation

taste is sensed by which cranial nerves?

1. facial CN7,

2. glossopharyngeal CN9,

3. vagus CN10

which CN innervates front 2/3 of tongue?

cn7 facial

which CN innervates back third of tongue

CN9 glossopharyngeal

which CN innervates throat and very back of tongue

CN10 vagus

papillae

bumps on tongue where most taste buds live

taste cells release an ____________ neurotransmitter onto the terminals of gustatory afferent nerves

excitatory

which taste receptors are simple ion channels

1. salt

2. sour

which taste receptors are g protein coupled

1. bitter,

2. sweet,

3. umami

what is the taste associated with T1 receptors

1. sweet

2. umami

what is the taste associated with T2 receptors

bitter

ageusia

loss of sense of taste

dysgeusia

constant unpleasant metallic taste in mouth resulting from damage to facial nerve

somatomotor system

controls striated skeletal muscles

autonomic motor system

sympathetic and parasympathetic control of heart, blood vessels, and digestive tract

upper motor neurons (UMNs)

start in cortex and target lower motor neurons

lower motor neurons (LMNs)

start in brainstem (as cranial nerves) or spinal cord (as spinal nerves) and directly target muscles

where do somas of the lower motor neurons sit

ventral horn of spinal cord

neuromuscular junction

motor neuron-muscle connection