Neuro Quiz 1

commissural tracts

connects the two hemispheres. transistor pole between 2 neighborhoods

association tracts

connects cortical areas within a hemisphere. telephone poles splitting off to the houses in the neighborhood

rostral/anterior

cerebrum - near front of head

brainstem or spinal cord - near or toward brain

general - towards the front/nose

caudal/posterior

cerebrum - back of brain or head

brainstem or spinal cord - coccygeal end of spinal cord

general - towards the back/bottom

Dorsal

cerebrum - top of brain

brainstem or spinal cord - back of brainstem or spinal cord

general - back or top (think fin on fish)

ventral

cerebrum - bottom of the brain

brainstem or spinal cord - belly or anterior in quadrupeds and bipeds

general - front

lateral

away from midline

medial

towards midline

superior

top

inferior

bottom

saggital

divides into left and right

coronal (frontal)

divides into front and back

axial (horizontal or transverse)

divides into top and bottom

Billions

How many neurons are in our nervous system?

Soma

cell body of neuron

components of soma

nucleus and cytoplasm

dendrites

branches of a neuron that conduct impulses moving toward the cell body. multi-polar

axon

takes info from the cell body and sends an action potential to terminal buttons to be sent to another neuron/neuromuscular junction via neurotransmitters across the synaptic cleft

glutamate

primary excitatory neurotransmitter for all CNS neurons. swift. gives the green light

Gamma-amniobutyric acid (GABA)

primary inhibitory neurotransmitter in the mature CNS, regulates muscle tone. Swift. Quickly corrects bad muscle movements on the fly e.g. stumbling

Dopamine

originates in substantia nigra and ventral tegmental area in the midbrain. involved in movement, motivation/reward, cognition and learning, attention, mood, sleep. Not enough = Parkinson’s

Acetylcholine

sole neurotransmitter involved in PNS control of skeletal muscle. Swift excitatory effect in PNS —> muscle contraction. Modulatory effect in CNS

nerve

collection of axons outside CNS

tract

collection of axons inside CNS

Nucleus

collection of cell bodies inside CNS

Ganglion

collection of cell bodies outside CNS

Neuoglia (glial cells)

support cells that act as glue. provide physical support nutrient flow, nerve housekeeping. janitor cells making sure everything is okay

Oligodendroglia and Schwann cells

glial cells that form the myelin that surrounds axons in CNS and PNS respectively. aka Nodes of Ranvier? (the notches in the myelin sheath)

Astrocytes

glial star-shaped cell throughout CNS. Aid in neuronal migration during development and help regulate neuronal metabolism. Role in blood-brain barrier preventing passage of metabolites from blood to the brain. supports scaffolding for neurons, provides nutrients, neural metabolism, regulates chemical composition of extra cellular fluid

ependymal cells

glial cells that line ventricular cells and form a barrier. they form the choroid plexus which makes cerebrospinal fluid (CNS). line cavities in brain

Microglia

few but scattered glial cells that transform into macrophages (scavenger cells) which seek pathogens and remove damaged tissue

connective tissues

glial cells that form meninges, and thin layers on myelinated nerve fibers

white matter

made up of myelinated axons

gray matter

mostly nerve cell bodies. makes up the cerebral cortex and sub-cortical nuclei

pyramidal cells

What are the largest cells in the brain?

Cerebral cortex organization

Horizontal - six cell layers — with each later containing a different type of cell

vertical -interconnected vertical columns each hold a functional unit of cells that share a related purpose and a related location of the stimulus that drives their function

4 categories and functions of the nervous system

• Sensor (receives all information and stores it)

• Effector (initiates and controls body movement)

• Integrator (analyzes and combines)

• Regulator (maintains homeostasis)

CNS

Brain + Spinal cord

brain function

initiating, controlling, regulating. In charge of ALL sensorimotor and cognitive functions

CNS protection

• skull

• vertebral column (bone and cartilage)

• meninges (3 membranes that encase the spine)

• CSF (cerebrospinal fluid between 2 meninges. mechanical buffer and chemical mediator)

PNS

spinal nerves + cranial nerves + somatic nervous system + autonomic nervous system

afferent fibers

nerves and cells that transmit sensory info to the CNS from the receptors contained within the skin, muscles and visceral organs

efferent fibers

motor fibers that take commands from the CNS to activate muscles and glands throughout the body

Somatic Nervous system function of afferent and efferent fibers

mediate skeletal muscle reflexes

Proencephalon

forebrain. divides into diencephalon and telencephalon

Mesencephalon

midbrain

Rhombencephalon

hindbrain. splits into myencephalon and metencephalon

frontal lobe

brain area in charge of motor and executive function. bound inferiorly be lateral sulcus and posteriorly by central sulcus. contains primary motor cortex, premotor area, Broca’s area, prefrontal cortex

Parietal lobe

brain area that interprets and discriminates sensory input. located posterior to the central sulcus, inferiorly by posterior end of lateral sulcus, and posteriorly by imaginary line. contains primary somatosensory cortex, somatosensory association cortex, angular and supramarginal gyri

Temporal lobe

Hearing center of the brain. inferior to lateral sulcus. contains primary auditory area (Heschl’s gyrus), auditory association area, and Wernicke’s area

Occipital lobe

vision center of the brain. located posteriorly in cerebral hemispheres. interpretation and discrimination of visual input. contains primary visual cortex and visual association cortex

Basal ganglia

involved in the control of movement. consists of corpus striatum and substantia nigra

Caudate nucleus and lentiform nucleus

parts of corpus striatum

Globus pallidus and putamen

parts of lentiform nucleus

Medulla oblongata

Part of the myencephalon. acts as a junction point between brainstem and spinal cord. decussation of the pyramidal tract (motor) and sensory fibers happens here. conduit for ascending and descending nerve tracts, houses the centers that control vital functions, contains the nuclei of 4 cranial nerves (9-12)

Medulla structures

• ascending and descending fibers

• interior cerebellar peduncle

• olivary nucleus

• reticular formation

Pons

Part of the metencephalon. Acts as a data warehouse switchboard. Lots of info transfer comes through

Pons structures

• corticospinal fibers

• cavity of the 4th ventricle

• middle cerebellar peduncle

• medial lemniscus

• pontocerebellar fibers

• trigeminal nuclear complex

• spinal trigeminal nucleus and tract

• superior cerebellar peduncle

Midbrain (mesencephalon) structures

• cerebral aqueduct

• inferior colliculus

• medial lemniscus

• superior cerebellar peduncle and decussation

• oculomotor nucleus and nerve

• red nucleus

• substantia nigra

• superior colliculus

Anencephaly

neural tube doesnt form, no cranial vault, we dont have a brain. cerebral hemispheres are either missing or reduced, absence of optic nerves. folic acid and multivitamins can aid in prevention. Incidence 1 in 1000 deliveries, more common in females. survival 3-48 hours after birth

Cranium Bifidum

Skull doesnt come all the way down, brain exits out. Bone fusion is prevented in the posterior midline of the skull. results in the brain or spinal cord protruding through the opening

Spina Bifida

Deficit in fusion of the dorsal part of the neural tube. Classified into several subtypes: cystica and occulta. Caudal displacement of cerebellar tissue through the foramen magnum results in Arnold-Chiari malformation

Hydrocephalus

Presents as enlarged head with a prominent forehead. Characterized by brain atrophy, seizures, enlarged ventricles due to excessive CSF, thinned cerebral mantle

Microcephaly

Presents as small brain and face. Cognitive deficits due to underdeveloped brain. Causes have been linked to environmental disturbances, genetics and ionizing radiation during initial CNS development

Holoprosencephaly

incomplete development of the midline structures, including fused eyes, single nasal chamber, single ventricle

Lissencephaly

Sulci and gyri do not develop, the brain is smooth