B&B Quiz 4

Neuro

forebrain surface features

cerebral peduncles, interpedunclar fossa, oculomotor nerve, trochlear nerve 

pons surface features

middle cerebellar peduncle, trigeminal nerve, abducens nerve, facial nerve, vestibulocochlear nerve

medulla surface features

anterior median fissure, pyramid, pyramidal decussation, hypoglossal nerve, olive, vagus nerve, acessory nerve

midbrain ventral features

cerebral aqueduct, superior and inferior colliculus

l*ook for cerebral peduncle on myelin stains*

pons ventral surface

4th ventricle

look for pontine nuclei and transverse pontine fibers and pryamidal tract fibers on myelin stain 

medulla ventral surface

Open and closed medulla

• closed has central canal

• open has 4th ventricle

*look for pyramid on myelin stain*

midbrain dorsal features 

trochlear nerve, superior and inferior colliculus

pons dorsal features

superior inferior and middle cerebellar peduncles

medulla dorsal features

obex, gracile tract

Base

most ventral surface of the brainstem

tegmentum

core of brainstem, region between base and ventricular system

tectum

dorsal to ventricular system

ONLY IN MIDBRAIN

Cross section 1 (closed medulla) features

motor pyramidal decussation along with central canal and pyramid

Cross section 2 (closed medulla) features

sensory decussation, dorsal column nuclei (gracile and cuneate nucleus), internal arcuate fibers, and inferior olivary nucleus

along with central canal and pyramid

cross section 3 (open medulla) features

fourth ventricle, pyramid, inferior olivary nucleus

cross section 4 (lower pons) 

facial nerve fibers (very distinctive black line on myelin stains)

along with pontine nuclei, pyramidal tract fibers, and transverse pontine fibers 

cross section 5 (Mid pons)

regular: pontine nuclei, pyramidal tract fibers, and transverse pontine fibers 

cross section 6 (lower midbrain)

decussation of superior cerebellar peduncle and inferior colliculus

along with cerebral peduncle and cerebral aqueduct and periaqueductal gray

cross section 7 (upper midbrain)

red nucleus and superior colliculus

along with cerebral peduncle and cerebral aqueduct and periaqueductal gray

pyramidal tract (corticospinal tract) function and brainstem structures

voluntary movement

brainstem structures: cerebral crus ( inside the cerebral peduncle), corticospinal fibers, pyramid, pyramid decussation (in MEDULLA)

lesion of the brainstem in the pyramidal tract means

paralysis of the contralateral side of the body

myelin stain looks white in the pyramid instead of usual black

Which cerebellar peduncle connects to which part of the brainstem? 

superior- midbrain

middle- pons

inferior- medulla and spinal cord 

lesion of the cerebellar system results in

ataxia ( uncoordinated movements)

What other lesions can cause ataxia? 

lesions of the brainstem in connections to cerebellum

what is the substantia nigra and its function?

motor center up against cerebral peduncle in midbrain

in parkinsons when the neurons degnerate here causes slower movements

Superior colliculus and function?

motor center for eye movements

in upper midbrain (top of myelin stain)

what is the function of inferior colliculus

sense of hearing

Brainstem nucleus, cross section, and location of oculomotor nerve (CN III)

oculomotor nucleus

upper midbrain

cross section 7

Brainstem nucleus, cross section, and location of trochlear (CN IV)

trochlear nucleus, lower midbrain. coss section 6

Brainstem nucleus, cross section, and location of Abduces (CN VI)

abducens nucleus, lower pons, cross section 4

Brainstem nucleus, cross section, and location of hypoglossal (CN XII) 

hypoglossal nucleus,  medulla, sections 2-3

Brainstem nucleus, cross section, and location of MOTOR trigeminal (CN V)

trigeminal motor nucleus, mid pons, section 5

Brainstem nucleus, cross section, and location of Facial (CN VII)

facial nucleus, lower pons, section 4

Brainstem nucleus, cross section, and location of gloosopharyngeal (CN IX)

nucleus ambiguus, medulla, sections 2-3

Brainstem nucleus, cross section, and location of vagus (CN X) 

nucleus ambiguus, medulla, sections 2-3

Brainstem nucleus and location of sensory of trigeminal nerve (CN V) 

in pons, principal sensory nucleus 

ALSO spinal trigeminal nucleus, in pons through medulla (form spinal trigeminal tract) 

Brainstem nucleus, cross section, and location of vestibulocochlear (CN VIII)

vestibular nuclei open medulla-lower pons, sections 3-4

ALSO cochlear nucleus, upper medulla, between sections 3 and 4

Brainstem nucleus, cross section, and location of Visceral Sensory Facial (CN VII)

solitary nucleus, most of medulla, sections 2-3

looks like a donut in myalin stain

Brainstem nucleus, cross section, and location of visceral sensory glossopharyngeal (CN IX) 

solitary nucleus, most of medulla, sections 2-3

looks like a donut in myalin stain

Brainstem nucleus, cross section, and location of visceral sensory Vagus (CN X)

solitary nucleus, most of medulla, sections 2-3

looks like a donut in myalin stain

function of reticular formation and myelin stain location 

consciousness, basic life support, and many others

location: like everything else of the brainstem ( all other area?)  

which artery is the main supplier of the midbrain

posterior cerebral arteries

which artery is the main supplier of the pons

basilar artery

which artery is the main supplier of the medulla

vertebral arteries

What is the medial supply of brainstem

paramedian branches of each main artery (EXCEPT: medulla paramedian branches of- anterior spinal artery)

What is the lateral arterial supplier for the midbrain

superior cerebellar artery (SCA) and posterior cerebral artery

What is the lateral arterial supplier for the pons

anterior inferior cerebellar artery (AICA)

What is the lateral arterial supplier for the medulla

posterior inferior cerebellar artery (PICA) 

forebrain=

diencephalon and telecephalon

structures of diencephalon

4 major nuclei: thalamus, hypothalamus, epithalamus, subthalamus

3rd ventricle and CN II

“gateway to cerebrum homeostasis” 

structures of the telencephalon

cerebral cortex, subcortical white matter, basal ganglia, hippocampus, amygdala

lateral ventricles and CN I

where is the mamillary body located 

in the hypothalamus 

name the Subdivisions of the thalamus

anterior, medial, and lateral thalamic nuclei divided by intralaminar nuclei

6 lateral subdivisions (ventral tier) 

ventral anterior (motor) 

ventral lateral (motor) 

ventral posterolateral (VPL somatosensory of BODY) 

ventral posteromedial (VPM somatosensory HEAD) 

lateral geniculate nucleus (LGN, vision) 

medial geniculate body (MGB, auditory) 

all pathways from subcortical sources to cortex synapse where?

thalamus first

function of hypothalamus

regulate homeostatic function via ANS and endocrine

function of pineal gland

produces melatonin

function of habenula

limbic and motivational control of behavior

Name the fissure between the two hemispheres of cortex

longitudinal fissure

4 lobes of the brain and functions

frontal- motor, speech, executive functions (planning problem solving)

parietal- somatosensation, high-level visual processing, sensory integration, attention (WEIRD SHIT)

temporal- auditory, olfactory processing, memory, high level visual processing

occipital- visual processing

postcentral gyrus

primary somatosensation (aka somatosensory cortex)

precentral gyrus

primary motor 

lateral surface (function and arterial supply)

head and upper upper body function, supplied by middle cerebral artery

medial lower body (function and arterial supply)

lower body function supplied by anterior cerebral artery

internal capsule (posterioe and anteiror limbs) 

efferent fibers. leaving the cerebral cortex and afferet fibers

posterior: lateral to thalamus

anterior: lateral to caudate nucleus 

fornix (function and location)

connects hypothalamus and hippocampus

underneath the corpus callosum and lateral ventricle

corpus callosum 

biggest; commissural fibers that connect two hemispheres

basla ganglia

3 primary nuclei: caudate, putamen, and globus pallidus (internal and external)

striatum

caudate nucleus and putamen

lentiform nucleus

putamen and globus pallidus

anterior limb is present if

the thalamus is absent

vice versa for posterior limb

amygdala function and location

processes emotions (FEAR)

medially in the temporal lobs, internal to uncus, anterior to hippocampus, circular

hippocampus (function and location)

alternating white and gray matter, seahorse shaped

anterior cerebral artery 

supplies frontal and parietal lobes 

middle cerebral artery

all lobes, and basal ganglia via lenticulostriate arteries

posterior cerebral artery

occipital, temporal, and parietal lobes

what deficits if strokes of lenticulostriate/MCA arteries

capsular stroke (motor deficits)

ACA

midline, lower body, paracentral lobule 

paracrine signaling (what is it, what speed, and what body responses)

signaling via diffusion within a tissue

short distance, fast/ moderate speed

seen in inflammation and local tissue coordination (histamine, FGF)

endocrine signaling (what is it, what speed, and what body responses)

signaling via the bloodstream

long distances, slow speed but long lasting

homeostasis, hormones like insulin, thyroid hormone, and cortisol

What are the three types of signaling molecules? Give examples of each. 

cell-impermeant: hydrophilic molecules such as neurotransmitters, insulin, and glucagon 

cell-permeant: hydrophobic molecules like steroid and thyroid hormones 

cell-associated: attched to the cell surface (eg. delta and ephrins) 

What is a channel linked cell receptor/ give examples?

pore proteins that sit on the cell membrane. They are ligand gated. that work fast with changes in membrane potential.

(nAChR, NMDAR, GABAaR, glycineR)

What is an enzyme-linked cell receptor/ give examples?

transmembrane protein that activate enzymes by ligand binding.

insulin receptor

What is a G-coupled protein cell receptor/ give examples?

ligand or neurotransmitter binding with G-protein as second messenger. Long lasting signal

metabotropic receptors for glutamate, GABA, and dopamine

What is an intracellular cell receptor/ give examples?

found in the cytoplasm or in the nucleus. They are lipophilic and act as transcription factors. Slower and more long lasting. 

thyroid hormone and estrogen receptors 

What type of response is the knee-jerk reflex?

bioelectrical circuit sensory to motor neurons by action potentials

What is an action potential?

very fast shift in membrane potential to more positive via ion channels

How does a sensory neuron transmit information?

First a graded receptor potential then by an action potential

How does a motor neuron transmit information?

first by a graded synaptic potential then by an action potential

How does a muscle cell receive information?

first by a graded synaptic potential then by an action potential

What is an EEG?

electoencephalo- graphy (test with many electrodes on the patients head to read brain activity) -gram (results of said test)

What is an EMG? 

electromyo-(graphy/gram) slightly invasive, put needles in skin and test electrical current in motor neurons and muscles that they innervate 

How does and EEG look during a seizure?

there is increased amplitude that is all synchronized

How does an EMG look when the patient has myasythenia gravis?

decreased amplitude with fast fatigue

What is an ECG?

Electrocardio(graphy/gram) reads the electrical impulses of the heart

what is neuromodulation? 

a regulation of neural activity through physical or chemical stimulation 

What is deep brain stimulation and ehat does it treat?

an invasive procedure where an implanted device sends electrical signals to certain parts of the brain

used to treat Parkinson’s

What is transcriptional magnetic stimulation?

a non-invasive procedure where magnetic impulses are used to stimulate the brain

used to treat depression

Explain the corticospinal tract 

nucleus in the motor cortex with a long axon that crosses the midline higher than where it meets the spinal nerve 

allows for voluntary motor control 

how many neurons is the fastest sensory pathway

three neurons