BIOL 2220: Unit 4 Test

what mesenchymal layer becomes the brain and CNS

ectoderm

sympathetic preganglionic neurons branch off of...

thoracic and lumbar spinal cord

parasympathetic preganglionic axons branch off of...

cervical and sacral spinal cord

steps of embryological development

1. ectoderm thickens along midline to form neural plate

2. neural plate invaginate to for neural groove and folds

3. folds fuse to form tube

4. neural crest develops as offshoot of neural folds, becomes ganglia

primary brain vesicles

prosencephalon, mesencephalon, rhombencephalon

prosencephalon

forebrain

mesencephalon

midbrain, does not develop into secondary vesicles

rhobencephalon

hindbrain

the proencephalon gives rise to...

telencephalon and diencephalon

the rhombencephalon gives rise to...

metencephalon and myelencephalon

cerebrum

from telencephalon, undergoes greatest structural changes

diencephalon

hypothalamus, thalamus, epithalamus, retina

Metencephalon

pons and cerebellum

Mylencephalon

medulla oblongata

brain ventricles

cerebrospinal fluid filled cavities within the brain, connect with spinal cord, expansions of lumen of neural tube

lateral ventricles

left and right, do not directly connect

third ventricle

the ventricle located in the center of the diencephalon

fourth ventricle

small triangular chamber between pons and cerebellum

interventricular foramen

connects lateral and third ventricles

cerebral aquaduct

connects the third and fourth ventricles

lateral apertures

Two openings in the side walls of the fourth ventricle that connect to the subarachnoid space

median apertures

holes by cerebellum that connect ventricle CSF to CSF in the subarachnoid space

aperture function

allows fluid to go out of brain to meninges

insula lobe

processes sensory information, emotional states and self awareness

frontal lobe

motor control and planning, decision making, personality, language

gyri and sulci function

allow for more cerebrum to fit in skull

parietal lobe

sensory perception, spacial awareness

temporal lobes

auditory processing, language, memory

occipital lobe

visual processing and recognition

white matter

deep to cerebral cortex, made of myelinated axons

- commissures, association fibers, projection fibers

commissures

connect cerebral cortex of both hemispheres

association fibers

connect different parts of the same hemisphere

projection fibers

two way path, ties cerebral cortex to res of nervous system, link between sensory and motor

basal nuclei

islands of gray matter buried within the white matter

- caudet nucleus, putamen, globus pallidus, amygdala

functions of basal nuclei

- similar to cerebellum

- refine skeletal muscle activity

- regulate stereotype movement (ie; eating)

- attention, cognition, emotion

- amygdala = fight or flight

cerebral cortex

differing degrees of thickness and structure linked to function, gray matter, mostly cell bodies, each hemisphere controls opposite side of body, no area acts alone

lateralization of function

right hemisphere -> visual/spacial tasks, art, music emotion

left hemisphere -> logic, language, math, science

functional areas of cerebral cortex

motor, association, and sensory areas

motor areas of cerebral cortex

primary motor cortex, premotor cortex, frontal eye field, broca's area

primary motor cortex

contracts muscles for skeletal muscle movements, pyramidal cells fine tune movement

premotor cortex

active during the planning of a movement, cannot directly control skeletal muscle, signals sent to primary motor cortex

Broca's area

left hemisphere only, motor area connected to speech, forming mouth shape and movement for words

frontal eye field

controls voluntary eye movements

sensory areas

-primary somatosensory cortex

-somatosensory association cortex

-visual and auditory areas

-olfactory, gustatory, and vestibular cortices

primary somatosensory cortex

receives signals from sensory receptors on the skin and proprioceptors, telling us where we are in space, figures out which part of the body is being stimulated

Somatosensory association cortex

integrates the information from primary somatosensory cortex

primary visual cortex

receives information from the retina of the eye

ex. football did not go through uprights

visual association area

interprets information from retina using prior experiences

primary auditory cortex

receives information from the inner ear

auditory association area

interprets information from inner ear

olfactory cortex

receives information from the nose

gustatory cortex

associated with the reception of taste

vestibular cortex

associated with sensations related to balance, located in the insula

association areas

-prefrontal cortex

-broca's and wernicke's

- general interpretation area

- visceral association area

prefrontal cortex

most evolved in humans

- associated with intellect, complex learning, recall, personality

-develops slowly, dependent on social feedback

wernicke's area

-left side of cerebrum

-used to sound out words

general interpretation area

- only on left side of brain

- integrates information from all other association areas into a single thought

visceral association area

-located in the cortex of the insula

-involved in conscious perception of visceral sensations (bladder full, upset stomach)

Cortex vs. Association area

association areas are specific parts of the cortex that aren't primary sensory or motor zones but instead integrate information

- if it doesn't start with primary it is an association area

thalamus

- all sensory information except for spinal reflexes travels through thalamus

- filters and codes sensory impulses, sending them to the correct cortex

hypothalamus

- internal organ control center

- associated with the autonomic nervous system

- controls food intake, water balance, sleep, hormone release

- daily maintenance

epithalamus

contains the pineal gland, secretes melatonin and produces CSF

brain stem

pons + medulla

- deep gray matter surrounded by white matter

- autonomic behaviors for survival: digestion, breathing, heartbeat

- connects higher and lower brain function

midbrain

- connects to both spinal cord and cerebellum

- pain suppression, physical reaction to emotion (links amygdala to ANS)

- visual reflex center (neck movement to eyball movement)

- auditory impulses travel through

pons

pathway between cortices and spinal cord

- connects cerebellum and motor cortex

medulla oblongata

- controls heart rate and blood vessel diameter

- rate and depth of breathing

- vomiting, swallowing, hiccuping

cerebellum

- refines skeletal muscle contractions

p plays role in cognition and problem solving

- subconscious activity

- gray cortex with internal white matter (arbor vitae)

steps of cerebellar processing

visual receptors, equilibrium receptors, motor association area of cerebral cortex --> cerebellar cortex calculates best path for muscle movement --> sends message to muscle --> muscle contracts

limbic system

emotional brain

- closely related to odor and smell

- output relayed through hypothalamus, resulting in gestures

- strong link between feelings and thoughts (feelings always override thoughts)

reticular formation

- loose cluster of neurons around midbrain and brainstem

- filters sensory information and sends to cerebral cortex

- linked to pineal gland and melatonin (wakes brain up)

EEG

recording of the waves of electrical activity that sweep across the brain's surface

alpha waves

slow brain waves of a relaxed, awake state

beta waves

awake and alert, concentrating

theta waves

common in children, vegetative, ignoring surroundings

delta waves

the large, slow brain waves associated with deep sleep

continuum of consciousness

alert --> drowsy --> lethargic --> stupor --> coma

NREM sleep

non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep

- restorative sleep

REM sleep

- go from alpha wave to beta wave

- rapid eye movements

- dreaming

- NREM-->REM 4 times , 4th time being the longest and the one we usually remembers

REM function hypothesis

- analyzing our day

- reverse learning , forgetting unimportant things and remembering important

memory

created by repeated use of neuronal pools/networks

- stimulus--> temporary buffer (filters) --> short term/working--> goes into long term with reppitition and association

meninges

cover CNS, protect blood vessels, contain CSF

dura mater

two layered sheet of fibrous connective tissue that covers the brain

- one layered around spinal cord

- strongest, outermost covering of meninges

arachnoid mater

middle meningeal layer

- creates a space as it is filled with fluid and blood vessels

pia mater

innermost meninx, immediately covers brain and spinal cord

cerebrospinal fluid

reduces brain weight, protects and cushions brain and spine, nourishes brain

- formed by leaky capillaries in brain ventricles

blood-brain barrier

Blood vessels (capillaries) that selectively let certain substances enter the brain tissue and keep other substances out

where is the BBB absent?

vomiting center (poison triggers vomiting)

hypothalamus (assesses blood temperature and water levels)

What substances can pass through BBB?

glucose (ATP), amino acids (building), electrolytes (APs)

spinal cord development

neural tube develops an alar plate (interneurons) and basal plate (motor neurons)

- plates become grap matter, everything surrounding becomes white matter

conus medullaris

end of CNS

filum terminale

fibrous extension of the pia mater; anchors the spinal cord to the coccyx

denticulate ligaments

extensions of pia mater that secure cord to dura mater

cauda equina

collection of spinal nerves below the end of the spinal cord

gray matter of spinal cord

nerve cell bodies arranged in a butterfly shape with anterior and posterior "horns"

white matter of spinal cord

myelinated axons "columns"

lateral horns of spinal cord

cell bodies of autonomic motor neurons

anterior horns of spinal cord

cell bodies of somatic motor neurons

posterior horns of spinal cord

cell bodies of somatic and visceral sensory neurons

dorsal root ganglion

pseudounipolar sensory neuron that synapes with PNS and interneurons of posterior hors

spinal cord tracts

bundles of axons that run in the white matter of the spinal cord

- stem from cell bodies in gray matter

- allow for signal amplification and transport to mulriple pathways

- most exhibit decussation and somatotopy

- have left and right pairs

- made up of x order neurons