Chapter 12: The CNS (Brain and Spinal Cord) Flashcards

4 steps:

1-neural plate forms from surface of ectoderm

2-the neural plate invaginates (folds), forming neural groove with neural folds

3-neural fold cells migrate to form neural crest, which forms much of the PNS and many other structures

4-the neural groove becomes the neural tube, which will form CNS structures

a neural canal

has two sides: anterior and posterior

Prosencephalon (forebrain)

Mesencephalon (midbrain)

Rhombencephalon (hindbrain)

1-Telencephalon (end brain)

2-Diencephalon (interbrain)

3-Mesencephalon (midbrain)

4-Metencephalon (after brain)

5-Myelencephalon (spinal brain)

Cerebrum: cerebral hemispheres

(cortex, white matter, basal nuclei)

Lateral Ventricles

Diencephalon (thalamus, hypothalamus, epithalamus), retina

Third Ventricle

Brain stem: midbrain

Cerebral Aquaduct

Brain Stem: pons

Cerebellum

Fourth Ventricle

Brain Stem: Medulla Oblongata

Central Canal

2 flexures develop...the midbrain flexure and the cervical flexure

both move the forebrain toward the brain stem

they grow back over and almost completely envelop the diencephalon and midbrain

more neurons to occupy the limited space

4 of them!

Lateral Ventricle

Third Ventricle

Cerebral Aquaduct

Fourth Ventricle

Ependymal Cells

subarachnoid space

cerebral spinal fluid (CSF)

85% of total brain mass

Gyri

sulci

Frontal

Parietal

Temporal

Occipital

Insula

fissures

separate large regions of brain

the brain into right and left hemispheres

the cerebral hemisphere from the cerebellum

outer layer of gray matter

neuron cell bodies

dendrites

neuroglia cells

blood vessels

NO axon or fiber tracts!!!

**billions of neurons arranged in 6 layers..(40% of brain mass)

Motor areas

Sensory areas

Association areas

interneurons

each hemisphere controls the sensory and motor functions of the opposite side of the body

some functions of the brain are mostly found in one side of the brain

no functional area of the cortex acts alone

conscious behavior involves the entire cortex in one way or another

pre central gyrus of frontal lobe

large neurons called pyramidal cells

conscious control of muscles

motor tracts called pyramidal tracts (corticospinal tracts) in the spinal cord where innervation is contralateral (as in taking place on opposite sides)

somatotopy

motor homunculi

just anterior to the precentral gyrus in the frontal lobe

Controls learned motor skills of a repetitious or patterned nature (ex: typing, piano, driving)

anterior to the inferior region of the premotor area

present only in the left hemisphere

special motor speech

partially in and anterior to the premotor cortex and superior to the Broca's Area

controls voluntary movement of eyes

loss of voluntary control (paralysis) of muscle

reflexes intact

loss of muscle motor memory

retain voluntary muscle control, but have to learn activities all over again

reflexes intact

in the post central gyrus of parietal lobe

sensory skin receptors (touch)

proprioceptors (position sense receptors)

**give a sense of spatial discrimination

and represented graphically by the somatosensory homunculus

just posterior to the primary somatosensory cortex

integrate sensory inputs

as in temperature, pressure, texture, size, memory

used when you pick up an object in your pocket without looking at it/feeling for something in the dark

on the extreme posterior tip of the occipital lobe

buried deep in the calcarine sulcus

receives visual info from the retinas

surrounds primary visual cortex and covers much of the occipital lobe

uses past visual experiences to interpret visual stimuli

enables us to recognize and appreciate what we see

each one is located in the superior margin of the temporal lobe abutting the lateral sulcus

interprets pitch, loudness, location

permits perception of sound stimulus:

understanding what we hear

storing memories of sound

Wernick's Area includes parts of the Auditory Cortex

on the medial aspect of the temporal lobe

makes us aware of different odors

in the insula, deep in the temporal lobe

involved in the perception of taste

in cortex of insula, posterior to gustatory cortex

perception of visceral sensations:

upset stomach, full bladder, constipation..

posterior insula, deep in the Temporal Lobe

helps with conscious awareness of balance, head position

1st-to the primary sensory cortex (you can see the words on the test)

2nd-to the sensory association cortex (you recognize the words as something you read)

3rd-to the multimodal association cortex (the words you read have meaning, based on memory)

Anterior Association Area (prefrontal cortex)

Posterior Association Area

Limbic Association Area

frontal lobe

intellect, complex learning, recall, personality, working memory, abstract ideas, judgment, reasoning, persistence, planning

heavily dependent on positive and negative feedback from one's social environment

temporal, parietal, and occipital lobes

role in recognizing patterns, faces, localization, binding sensory inputs, understanding written and spoken language

way to remember: mmm..look at that guy's posterior!

cingulate gyrus, hippocampus areas

provides the emotional impact of a scene

each hemisphere has some unique abilities

language, math, logic

visual-spacial, intuition, emotion, art, music

right-handed

are reversed or share functions equally

myelinated fibers bundled into large tracts

the direction in which they run

Commissural Tracts

Association Fibers

Projection Fibers

corpus callosum--it connects the right and left hemispheres

Connect different parts of the same hemisphere

connect the cerebral hemispheres to the lower brain and spinal cord

spots deep in the brain where large groups of neuron cell bodies are located

Caudate nucleus

Putamen

Globus Pallidus

important in starting, stopping, and monitoring the intensity of movements executed by the cortex, especially if they are slow or stereotyped

ex: swinging arms when walking

AND inhibit unwanted movements

ex: absent in Huntington's Chorea and Parkinson's Dz--Chorea (dance)

one of the Diencephalon brain structures

composed of multiple separate nuclei

2 egg-shaped collections of nuclei in the center of the brain with a small space between them called the 3rd ventricle

a space between 2 egg-shaped collections of nuclei inside the thalamus

small connection between the 2 egg-shaped collections of nuclei inside the thalamus

sorting and editing information

processing touch, pressure, pain

directing information to appropriate locations

below the thalamus

mammillary bodies

infundibulum

relay stations in the olfactory pathway

the connecting stalk of pituitary

autonomic control center

center for emotional response

body temp regulation

regulation of food intake

regulation of water balance and thirst

regulation of sleep-wake cycles

control of endocrine system functioning

most dorsal part of the diencephalon

forms the roof of the third ventricle

pineal gland is located here

secretes the hormone melatonin to regulate the sleep-wake cycle

midbrain

pons

medulla oblongata

Brain Stem

between the diencephalon and the pons

in the middle of the midbrain joining the 3rd and 4th ventricles

periaquaductal gray matter

involved in pain suppression and serves as a link for the fight-flight response

Midbrain

in between the midbrain and medulla oblangata

4th ventricle

Pons

between the pons and the spinal cord

Medulla Oblangata

a collection of longitudinal fibers

fibers that cross from left to right and vice versa (the cross-over point)

CN VIII, CN IX, CN X, CN XI, CN XII

Cardiovascular center (for heart rate)

Respiratory center (for rate of breathing)

vomiting, hiccuping, swallowing, sneezing, coughing (reflexes)

"small brain"

behind the pons and medulla

below the transverse cerebral fissure

precise contraction of skeletal muscles for smooth, coordinated movements (as in driving, typing, sports)

all of these functions are subconscious

emotional or affective feelings

helps recognize facial expressions

helps assess danger

elicits fear response

a connection with an emotion that can induce an illness (like anxiety)

extends through the core of the medulla oblongata, pons, and midbrain

sends continuous stream of impulses to the cerebral cortex to keep it alert and enhance excitability

can filter out familiar or weak signals so you can focus on new things

The Reticular Activating System*

layers around the brain

Dura mater

Arachnoid mater

Pia mater

are partitions that subdivide the cranial cavity of the dura mater

between right and left hemispheres

between right and left cerebellum

separates the cerebrum and cerebellum

subdural space and subarachnoid space

the arachnoid mater and pia mater

CSF

directly attached to the brain

ex: falx cerebri, falx cerebelli, tentorium cerebelli

in and around spinal cord and brain

protects brain and spinal cord

in the roof of each ventricle

a bunch of capillaries where CSF is released

being formed and reabsorbed

replaced every 8 hours

about 500 ml is formed per day

lateral ventricles --> foramen of Monro/third ventricle --> aqueduct of Sylvius --> fourth ventricle --> foramina of Magendie and Luschka --> subarachnoid space over brain and spinal cord --> reabsorption into venous sinus blood via arachnoid granulations

CSF accumulation

spinal dura mater and CSF and an epidural space is exterior to the spinal dura mater

L1 or L2

conus medullaris

a bunch of sacral nerve fibers that come out of the conus medullaris like a horse tail

the cauda equina

The gray matter of the spinal cord looks like the letter "H" or like a "butterfly"

central canal

central canal

the dorsal horns

where afferent fibers bring info into the spinal cord

where a dorsal root ganglion is part of the entering nerve

ex: nerve fiber stretched by reflex hammer

the ventral horns

where efferent fibers project information out of the spinal cord

ex: muscle is stimulated by nerve to contract