nsci 2101 exam 2

is the brainstem evolutionarily old or young

old; monoamines are old as well!

major divisions of the brainstem

medulla, pons, midbrain

the fourth ventricle partially covers the rostral half of which division of the brainstem

rostral medulla

location of and major structures in the caudal medulla

location: right next to the spinal cord; has the following major structures:
spinal trigeminal nucleus
spinal trigeminal tract
left dorsal funiculus
nucleus gracilis
nucleus cuneatus
pyramidal decussation
pyramidal tracts

gross structures of the rostral medulla

inferior olive,
inferior cerebellar peduncle
pyramidal tracts
sulcus limitans
4th ventricle

what is the reticular formation

regions with neurons but lacking clear nuclear boundaries, involved in sleep , wakefulness, autonomic function, and other non-conscious behaviors

what creates the big bulge of the pons

the pontine nuclei

what happens to the pyramidal tracts at the pons?

they break into bundles called pyramidal fascicles

monoamine neurons and their transmitter

raphe nuclei: serotonin
locus coeruleus: norepinephrine

what mainly attaches the cerebellum to the pons

the middle cerebellar peduncle

the caudal midbrain contains the inferior colliculi, what processing is this involved in?

auditory processing

the middle midbrain contains the superior colliculi, what processing and control is this involved in?

control over trunk muscles, response to visual and auditory stimuli

the rostral midbrain junctions with what

the diencephalon

the prosencephalon in turn develops into what 3 things?

diencephalon, telencephalon, retina

parts of the diencephalon

hypothalamus, subthalamus, thalamus, epithalamus

functions of the hypothalamus

many essential functions; temperature regulation, feeding and drinking, circadian rhythms, aggression and fright, sexual activity, neuroendocrine function

which neurons release hormones into the blood that act on the pituitary gland? (hint: it's a diencephalon structure)

hypothalamus

two types of nuclei in the thalamus and their functions

relay: relay sensory information or motor information to specific regions of the cortex
diffuse: have diffuse projections to cortex or within thalamus

what separates the two halves of the thalamus

third ventricle; the two halves touch at the interthalamic adhesion

what is the internal medullary lamina

sheet of myelinated axons that divides the thalamic relay nuclei into 3 regions: anterior, medial, and lateral

relay projection nuclei send axons to the cortex; this projection is _____

ipsilateral

lateral thalamic relay nuclei responsible for motor

ventral anterior, ventral lateral

lateral thalamic relay nuclei responsible for touch and pain

ventral posterior lateral, ventral posterior (medial)

lateral thalamic relay nucleus responsible for vision

lateral geniculate nucleus

lateral thalamic relay nucleus responsible for hearing

medial geniculate nucleus

the flow of information from the thalamus to the cortex is gated by what two things?

inputs from the cortex and from the brain stem reticular activating system, via the reticular nucleus of the thalamus

which limb of the internal capsule serves the frontal lobe

the anterior limb

which limb of the interior capsule serves the parietal, occipital, and temporal lobes

posterior limb

three interrelated parts of the telencephalon

neocortex (most cerebral cortex), limbic and olfactory systems (partly allocortex), basal ganglia

what does the allocortex contain? (brain structure)

hippocampus

what layer of the neocortex projects back to the thalamus?

layer 6

what layer of the neocortex receives input from the thalamus?

layer 4

what layer of the cortex projects to the lower CNS

layer 5

where does layer 4 of the neocortex project

layers 2 and 3

what is a cerebral commissure

discrete bundle of axons that cross the midline
there are two main commissures; the corpus callosum and the anterior commissure

what lobe is the hippocampus in

temporal

where is the amygdala located (lobe)

anterior temporal lobe, in front of the hippocampus

Papez circuit (limbic system); disrupting this disrupts memory

Hippocampus->mammilary bodies->anterior n. thalamus->cingulate cortex->hippocampus

what are the basal ganglia

a group of nuclei in the midbrain, diencephalon, and basal telencephalon with important roles in the motor system, motivation, and drug addiction

major nuclei of the basal ganglia

striatum (telencephalon), globus pallidus (telencephalon), subthalamic nucelus (diencephalon), substantial nigra (midbrain)

striatum three subnuclei

caudate nucleus, putamen, nucleus accumbens (BIG in drug abuse)

two divisions of the globus pallidus

external and internal
external deals with internal circuitry of the GP
internal deals with output circuitry

CN1

Olfactory

CN2

Optic

CN3

oculormotor

CN4

trochlear

CN5

trigeminal

CN6

abducens

CN7

facial

CN8

vestibulocochlear

CN9

glossopharyngeal

CN10

Vagus

CN11

spinal accessory

CN12

hypoglossal

cranial nerves carrying special senses

CN1, olfactory-smell
CN2, optic-vision
CN8, vestibulocochlear- hearing

cranial nerves only innervating skeletal muscle (5)

CN3, occulomotor- eye
CN4, trochlear-eye
CN6, abducens-eye
CN11, spinal accessory- neck and throat
CN12, hypoglossal-tongue

what is the only cranial nerve to exit the dorsal surface of the brain?

CN4, the trochlear nerve

where does CN11 exit enter and exit?

enters through foramen magnum, exits through jugular foramen

cranial nerve that innervates muscle and carries touch, pain, and vibration

CN5, trigeminal

only cranial nerve to exit the pons

CN5, trigeminal

mixed function cranial nerves

CN7, facial
CN9, glossopharyngeal
CN10, vagus

which 2 mixed cranial nerves carry information about CO2 and O2 and/or blood pressure

9 and 10; glossopharyngeal and vagus

3 subdivisions of the trigeminal nerve (CN5)

ophthalmic (forehead)
maxillary (cheek and nose)
mandibular (lower jaw)

the somata of somatosensory primary afferent neurons are located in

dorsal root (spinal) ganglia and cranial nerve sensory ganglia

dorsal roots only carry what type of information

sensory information

what is the main somatosensory nerve for the head

the trigeminal nerve

how does somatosensation enter the CNS

through the dorsal roots

true or false: proprioceptors are also mechanoreceptors

true, they are just specialized mechanoreceptors

what is proprioception

the sense of position, movement, and load on the trunk and limbs

mechanoreceptors express which receptor protein

Piezo2

what does a stronger simulation mean with regard to membrane depolarization?

the membrane depolarization will be larger

where are the spinocerebellar tracts located

lateral funiculus of spinal cord

two pathways from periphery to the cerebral cortex

proprioception and touch mostly via dorsal columns, pain, temperature, itch, and some touch via the spinothalamic tracts

pain can be provoked by the activation of what

nociceptors

nociceptors signal what?

tissue damage or the threat of tissue damage

primary afferent axons that carry pain are?

thin and slow

true or false, thresholds for nociceptors are usually HIGHER than most other sensory receptors?

true

Outer eye

cornea, sclera

middle eye

iris, ciliary body, choroid

inner eye

retina, continuous with optic nerve and brain