Central Nervous System

two parts of central nervous sytem vs peripheral nervous system

central: brain and spinal chord

peripheral: cranial nerves and spinal nerves

afferent vs efferet

afferent: to/towards aka info moving toward the CNS

efferent: info moving away from the CNS

what kind of input is afferent? what about efferent?

afferent: sensory

efferent: motor

what are the four major functions of the CNS

1. receiving and processing external sensory info (afferent)

2. integrating info form a wide range of sources, processing it, acting on it, and/or storing it in memory

3. sending signals that contro the main functions of body tissues (efferent)

4. consciousness, perception of language, reason, and memory, emotion, etc.

two divisions of nervous sytem

peripheral and central nervous sytem

what is a group of neuron cell bodies called in CNS vs PNS

CNS: nucleus

PNS: ganglion

what is a bundle of axons called in a CNS vs PNS

CNS: tract

PNS: nerve

what are the seven main parts of CNS?

1. spinal chord

2. medulla oblongata

3. pons

4. cerebellum

5. midbrain

6. diecencephalon

7. cerebral hemisphere

what are the two cell types of the nervous system?

neurons and glia

three types of glia

endymal cells, microglia, and astrocyte

what are the three ways we classify neurons

1. morphologically

2. functionally

3. NT released

three morphological classifications

1. pseudounipolar (only one process/not seen in humans/splits into two but ultimately only comes from one source/goes one direciton)

2. bipolar (two axon terminals that can go in opp directions

3. multipolar: multiple axon terminals that go in different directions

three functional classifications for neurons

interneuron, afferent neuron, and efferent neuron

what are the three NTs we focus on for classifying neurons

1. glutamate (Glu): commonly an EPSP in post synaptic cell

2. GABA: mainly an IPSP in postsynapitc

3. Acetylcholine (ACh): epsp vs ipsp depends on the receptor

list all 7 parts of CNS in order from most superior (very top) to most inferior (lowest position)

7. most superior: cerebrum

6. diencephalon

5. midbrain

4. cerebellum

3. pons

2. medulla (oblongata)

1. most inferior spinal chord

what are the two parts of a forebrain

cerebrum and diencephalon

what are the four parts of the cerebrum

cerebral cortex, basal ganglia, hippocampus, amygdala

what are the two parts of the diencephalon

thalamus and hypothalamus

what is the phenomenon when impulses that cannot generate an action potential alone aggregate from different locations on a neuron to cause depolarization?

spatial summation

afferent vs efferent effectors just directionality

afferent goes IN

efferent goes OUT

SAME DAVE acronym

Sensory

Afferent

Motor

Efferent

Dorsal

Afferent
Ventral
Efferent

what is the information superhighway

brain ←> spinal chord

where is the gray matter in the brain vs spinal chord

brain: outer

spinal chord: central

dorsal vs ventral

dorsal: back

ventral: front

what are the parts of the central gray matter in the spinal chord

two dorsal horns in the back

two ventral horns in the front

what direction is afferent info going and where does it come in? what type of info?

direction: bottom up/ascending tracts (but comes in through dorsal/back)

sensory ingo

what direction is efferent info going and where does it go out? what type of info?

it is going out from the ventral and top down control/descending tracts

motor information

how does the CNS stimulate skeletal muscle contraction?

efferent pathways of the somatic motor system

which lobe does efferent/afferent info go?

efferent (out): frontal lobe (because motor control)

afferent (in): parietal, occipital, and temporal (all somatosensory)

describe the ascending tracts/afferent pathways

joint stretch/touch/pain/temperature receptor → medulla oblongata (crossing over) → thalamus → postcentral gyrus (somatosensory map)

what kind of neurons are the receptors composed of?

pseudounipolar

where does crossing over occur for the afferent pathway

medulla oblongata

describe the descending tracts/efferent pathways

*In corticospinal tract (aka spinal chord)

primary motor area of cerebral cortex (usually frontal lobe)→medulla oblongata (crossing over) → skeletal muscle (outward motor info)

where does crossing over occur for efferent pathways?

medulla oblongata

what are the five parts of the extrapyramidal tract (do not worry about name just other parts besides spinal chord) that are helpful for movement?

1. brain stem

2. primary motor cortex

3. thalamus

4. cerebellum

5. basal ganglia

(and spinal chord)

which gyrus is above the central sulcus? below?

above: precentral gyrus

below: postcentral gyrus

what is the postcentral gyrus for vs precentral

postcentral: somatosensory (afferent)

precentral gyrus: motor area (efferent)

which gyrus is responsible for the primary motor cortex? primary somatosensory gyrus?

motor: precentral gyrus

somatosensory: postcentral

why do we use a homonculus to represent the topagraphical maps/the different gyrus’s?

because it corresponds to the cortical area devoted towards that specific sensory input/motor output

what side and lobe does somatosensory info go if it is coming from the left side?

it goes to the right side parietal lobe

what side and lobe of the brain controls the motor movement on the right side of the body?

the left frontal lobe

decussation meaning?

crossing over of fibers

summarize information superhighway (SAME DAVE)

sensory information (afferent) coming in via the dorsal horns via ascending tracts of spinal chord (bottom up processing)

motor information (efferent) leaving via the ventral horns of the spinal chord. goes down top down processing of descending tracts

do ventral root ganglia exist?

no

what is the soma?

cell body

what are gangila

collection of cell bodies

what kind of neurons are primary sensory (afferent) neurons?

pseudounipolar

what kind of neurons are motor (efferent) neurons?

multipolar

what does the single green or red line? what does the circle represent? what does the line represent? what does the yellow structure represent?

1. single green or red line: one representative axon/neuron

2. circle: soma of neuron

3. line: axon

4. yellow structure: PNS and many neuronal cell bodies (ganglia) and collections of many axons (nerves)

what do we call a group of neuron cell bodies (gray matter) in CNS vs PNS?

CNS: nucleus

PNS: ganglion

what do we call a bundle of axons (white matter) in CNS vs PNS?

CNS: tract

PNS: nerve

what is in the gray matter vs white matter

gray: cell bodies (nucleus CNS or ganglion PNS)

white: axons (tracts CNS nerves PNS)

what are the names for the peaks and valleys of the brain convolutions

peaks: gyrus

valley: sulcus

what are the four lobes of the cerebrum

frontal, parietal, occipital, and temporal

what are the three subcortial regions of the cerebrum

basal gangila, hippocampus, and amygdala

describe the anatomy of the cerebral cortex

central sulcus divides frontal and parietal lobe

precentral gyrus (motor) is above the central sulcus in frontal lobe (closer to eyes) and postcentral (sensory) is below central sulcus in parietal lobe

lateral sulcus separates temporal lobe from frontal, parietal, and occipital

occipital is on far bacl

longitudinal fissure divides brain in half vertically

eyes→frontal→parietal→occipital

what does contralateral mean? ipsilateral?

contralateral: cross other side

ipsilateral: stay on its side

what is the corpus callosum

the tracts that connect/allow for communication between hemisphere

precentral gyrus function

primary motor cortex involved with control of voluntary muscles

postcentral gyrus function

somatosensory cortex (for the senses)

brief description of frontal vs. temporal vs. parietal vs. occipital function

frontal: houses prefrontal cortex; high cognitive function

temporal: learning/memory/hearing

occipital: visual cortex

parietal: comprehension of language is one aspect

where is the broca’s area? Wernicke’s area? function of both? (include left or right side)

broca: frontal lobe for outputting language (motor makes sense with precentral gyrus in the same lobe) (left side)

Wernicke’s: parietal and temporal lobe for language comprehension (left side)

describe what we would see if we did a cross section of the cerebral cortex?

cell layering!

the two broadest cellular categories are neuronal and glial cells. what are two major neuron types

• projection neurons and local interneurons

describe projection neurons

pyramidal cells and are typically glutamatergic (mostly excitatory/release glutamate from nerve terminals)

describe local interneurons

they are in all cell layers and are GABA-ergic (release GABA → always IPSP/hyperpolarization)

what are the functions of the three subcortical regions of the cerebrum? (HAB)

• hippocampus: learning and memory

• amygdala: emotion and memory (part of limbic system→memory based)

• basal ganglia: control of voluntary movement

what kind neurons are interneurons

inhibitory multipolar

how do we classify afferent neurons

pseudounipolar or bipolar and excitatory

how do we classify efferent neurons

multipolar and depends