Chapter 2 - What is the Nervous System's Functional Anatomy?

agenesis

the failure of brain regions to develop, offers researchers an opportunity to study brain organization and function

What are 2 symptoms of agenesis?

-slow language development and motor function

-some early autism symptoms (hard to communicate)

________ __________ in response to early perturbations allows for _______ as regions of the cerebral cortex begin to function more efficiently.

brain plasticity; compensation

What is the brain's primary function?

to produce movement (aka behavior)

Without ______, the brain cannot properly orient the body and direct it to produce appropriate behaviors. An example of this would be ______.

stimuli; when you're in water and you can't orient yourself because you don't know what's up vs. down

The nervous system _______ sensory information to construct a ________ experience of reality (ie ____________)

integrates; subjective; perception

________ __________ is essential to carrying out any complex behavior. Give an example.

subjective reality; a ringtone is movement of air molecules, which cause the ear drum to vibrate and our current cognitive process takes over to decode this as a ringtone. Without a nervous system to decode this information, we wouldn't be able to perceive this sound.

Why do human brains and dog brains construct different realities (ie process sensory input differently)?

their brains and nervous systems developed different characteristics and features because each species had to adapt to solve different survival problems

What is meant by the phrase 'the brain is plastic'? Give an example.

neural tissue has the capacity to adapt to the world by changing how its functions are organized. Neural connections constantly change in response to experience. For example, when Cameron had a hemispherectomy (her entire left hemisphere was removed), all of her brain function became localized in her right hemisphere.

When does learning take place?

when neural circuits change to represent/store new knowledge

neuroplasticity (give an example)

the nervous system's potential to physically or chemically modify itself in response to environmental change and to compensate for age-related changes and injury

ex: blind people have enhanced auditory capacities because their brain changes in response to not being able to see (environmental change)

Describe the anatomical and functional organization of the nervous system.

anatomical organization:

-nervous system

--> central nervous system

-brain

-spinal cord

--> peripheral nervous system

-somatic nervous system

-autonomic nervous system

-enteric nervous system

functional organization:

--> central nervous system (mediates behavior)

-brain

-spinal cord

--> somatic nervous system (transmits sensation and produces movement)

-cranial nerves

-spinal nerves

--> autonomic nervous system (balances internal functions like circadian rhythm, breathing and rest/digest responses)

-sympathetic division (arousing)

-parasympathetic division (calming)

--> enteric nervous system (controls the gut)

afferent

-information that is incoming to the CNS

-sensory (incoming) pathways are afferent

efferent

-information that is leaving the CNS

-motor (outgoing) pathways are efferent

Describe how afferent and efferent systems work together using an example.

when you step on a tack, afferent sensory signals are sent to the brain, pain is perceived by the brain, efferent signals cause a motor response

brain-body orientation. which terms are used?

frame of reference is human face

-dorsal/ventral

-anterior/posterior

-medial/lateral

spatial orientation. which terms are used?

frame of reference is other body parts and body orientation

-dorsal/ventral

-anterior/posterior

-medial/lateral

-rostral/caudal

anatomical orientation. which terms are used?

frame of reference is direction of cut, section through the human brain from viewer perspective

-coronal section

-horizontal section

-sagittal section

dorsal/ventral

top/bottom

anterior/posterior

front/back

medial/lateral

middle/sides

rostral/caudal

beak/tail

coronal section

cut in a vertical plane, from the crown of the head down, yielding a frontal view of the brains internal structures

horizontal section

the view/cut falls along the horizon, or is viewed looking down on the brain from above (dorsal view)

sagittal section

cut lengthways from front to back and viewed from the side

ipsilateral

structures lying on the same side of the brain

contralateral

structures lying on opposite sides are contralateral to each other

bilateral

structures that occur in each hemisphere of the brain

proximal/distal

close to one another/far from one another

meninges

-consists of the following layers: dura matter, arachnoid membrane, pia matter (in that order, from lateral to medial)

-encases the brain and spinal cord. cerebrospinal fluid (CSF) cushions them.

What is meningitis? Why does it occur? What are the symptoms?

-inflammation of the meninges

-occurs because harmful viruses or microorganisms invade and multiply in the layers (particularly the medial ones, the pia matter and arachnoid layer but also the CSF between these layers) of the meninges

-symptoms include: severe headache, stiff neck, head retraction, convulsions (if the inflammation is affecting the brain)

encephalitis

inflammation of the brain tissue caused by an infection or autoimmune response (which is where immune system can't tell the difference between healthy and problematic cells, so body cells attack healthy cells)

Name the four main lobes of the brain and (briefly) their functions.

frontal lobe (executive function)

parietal lobe (sensory/spatial information)

temporal lobe (auditory, taste, smell, memory, language)

occipital lobe (visual)

cortex

outer forebrain layered tissue

gyrus (plural gyri)

bumps in the brain's folded surface

sulcus (plural sulci)

cracks in the brain's folded surface

fissure

the huge folds (not little wrinkles) in the brain matter

There are _______ major arteries that feed blood to the cerebral hemispheres. They are:

three; the anterior cerebral artery, the middle cerebral artery, the posterior cerebral artery

strokes

sudden neurological symptoms following severely reduced blood flow

The anterior cerebral artery supplies blood to...

the top of the brain

The middle cerebral artery supplies blood to...

the sides of the brain

The posterior cerebral artery supplies blood to...

the bottom of the brain that surrounds the brainstem

grey matter

neurons, surround white matter in the middle of the brain, mostly cell bodies and capillary blood vessels

white matter

glial cells, surrounded by grey matter on the outside of the brain, nerve fibers covered by myelin sheath

What does the myelin sheath allow for?

the nerve fibers covered with myelin sheath (in the white matter of the brain) can cover longer distances and signals can travel faster

ventricles

cavities within the brain filled with cerebrospinal fluid

cerebrospinal fluid

-fills the ventricles

-suspends brain to reduce mass weight (and pressure)

-shock absorber

-chemical content of CSF provides stable environment for optimal functioning

-effective waste cleaning (ventricles connect to aqueducts which connect to spinal cord)

Where are the four ventricles located?

-right lateral ventricle

-left lateral ventricle

-third ventricle is located under the two lateral ventricles and the corpus callosum

-fourth ventricle is located in between the brainstem and the cerebellum

nuclei (singular nucleus)

a group of cells within white matter forming a cluster that can be identified with special stains to form a functional grouping

Neurons are connected to one another by fibers known as ______.

axons

nerve

large collection of axons coursing together outside the CNS

tract

large collection of axons coursing together inside CNS (brain and spinal cord)

Go to the third last slide of 9/14/22 presentation. Without looking, name the parts of the vertebrate embryo.

*see pics in slides

Go to the third last slide of 9/14/22 presentation. Without looking, name the parts of the mammalian embryo.

*see pics in slides

Go to the third last slide of 9/14/22 presentation. Without looking, name the parts of the fully developed human brain.

*see pics in slides

Several nervous system layers do more than simply replicate function. Each region adds a different ______ to the behavior. This _______ organization affects virtually every human behavior.

dimension; hierarchical

_______ history, _______ history, and _______ history are integrated at the various anatomical and functional levels of the nervous system.

evolutionary; developmental; personal

How does the spinal cord mediate behavior?

-controls most body movements

-can act independently of the brain

How does the spinal reflex work? Give an example.

-the brain cannot inhibit this automatic movement, so it's hard to prevent

-ex: knee-jerk reflex

brainstem (location and function)

-begins where spinal cord enters skull

-receives afferent nerves coming from senses and sends efferent nerves out to control mostly all body movements

What are the three regions of he brainstem? Using your forearm, where are they?

-hindbrain

-midbrain

-diencephalon

*see slide 4 part 3

hindbrain

controls various motor functions ranging from breathing to balance to fine movements

-is evolutionarily the oldest part of the brain

-contains the cerebellum, reticular formation (flow of stimulation to the rest of cortex), pons (various body movements/functions) and medulla (vital functions like breathing and heart rate) which integrate voluntary and involuntary body movements

The cerebellum is _______ in animals that use finely coordinated movements.

larger

Why does sleep paralysis occur?

Pons is playing tricks on you, it happens when you're stressed out and/or drunk

Name the parts of the midbrain and point to where they are on the diagram (see Part 3)

tectum, tegmentum, red nucleus, substantia nigra, periaqueductal gray matter

tectum

roof of midbrain responsible for visual and auditory sensory processing) and orienting behaviors (auditory and visual systems must share a map of the external world so the ears can tell the eyes where to look). also contains the superior and inferior colliculi which produce orienting movements.

superior colliculus

part of the midbrain tectum that receives optic nerve fibers and thus plays a role in orienting behaviors

inferior colliculus

part of midbrain tectum that receives input from auditory pathways and thus plays a role in orienting behaviors

tegmentum

floor of midbrain, responsible for movement related functions. composed of many nuclei.

red nucleus

part of midbrain responsible for limb movements

substantia nigra

part of midbrain responsible for movement initiation (damages are associated with Parkinson's disease)

periaqueductal gray matter

part of midbrain responsible for species typical behaviors

The midbrain is also generally (no specific part) responsible for _______ _________.

pain modulation

diencephalon (location and function)

above the roof of your mouth and contains the hypothalamus and thalamus; the between brain which integrates sensory and motor information on its way to the cerebral cortex.

hypothalamus ("the pharmacy")

controls body's production of hormones. contains many nuclei associated with temperature regulation, eating, drinking, sex and nearly all aspects of behavior

thalamus

gateway for sensory information --> projects information wherever it needs to be projected; structure through which sensory information from all sensory systems is organized, integrated and projected into the appropriate region of the neocortex.

forebrain general function and point to where the different structures that are part of the forebrain are located

forebrain integrates sensation, motivation, emotion, memory and selective attention. it facilitates advanced cognitive functions such as thinking, planning, and using language. the forebrain structures are the cerebral cortex, basal ganglia, limbic system, neocortex and allocortex (see Part 3 slides for diagram)

cerebral cortex structure and function

-contains concentric rings of allocortex and neocortex

-makes most of the forebrain volume

-most expanded by evolution

-involves folding of neocortex (sulci and gyri)

allocortex structure and function

-made by three and four layered structures including the hippocampus (memory consolidation), part of the amygdala (anxiety and fear), the cingulate cortex (emotion formation and processing, learning, memory, linking behavior to motivation) several structures that make up the olfactory system (olfactory bulbs and receptors)

neocortex structure and function

-different layers have different cell types

-density of cells varies among layers

-connected to virtually all other parts of the brain

-ultimately creates reality

cytoarchitectonic map

Map of the neocortex based on the organization, structure, and distribution of the cells.

basal ganglia structure and function

-collection of nuclei just below the white matter of the neocortex: caudate nucleus, putamen, globus pallidus

-controls voluntary and involuntary movement

Example of neocortical layering:

-Layer IV is relatively ____ in the sensory cortex and relatively ____ in the motor cortex.

-abundant ______ sensory information from the thalamus connects to layer IV

-conversely, layers V and VI are relatively ______ in the motor neocortex and _____ in the sensory neocortex.

-______ motor information in layer V makes up the corticospinal track, connecting the motor neocortex to the spinal cord to _____ ______, and later VI connects to other cortical areas.

-thick; thin

-afferent

-thick; thin

-efferent; generate movement

somatic nervous system is monitored and controlled by the _______.

CNS

cranial nerves are controlled by the ________, whereas spinal nerves are controlled by _____ ______ segments.

brain; spinal cord

cranial nerves

twelve pairs control sensory and motor functions of the head, neck, and internal organs. Both afferent and efferent functions.

dermatomes

body segment corresponding to a segment of the spinal cord; each one is liek it's own mini brain

the higher up you sustain damage on your spine, the _____ likely you are to lose function of both your arms + legs.

more

Spinal nerves

-the spinal cord lies _____ the bony spinal column made of small bones called _______.

-vertebrae are categorized into five anatomical regions: ________, ________, _______, ________ and __________.

-spinal cord segments are ___________, so adjacent segments can operate together to direct complex _______ _________.

-inside; vertebrae

-cervical, thoracic, lumbar, sacral, coccygeal

-interconnected; complex movements

Law of Bell and Magendie

The general principle that sensory fibers are located dorsally and motor fibers are located ventrally. -Posterior fibers are afferent: they carry information from the body's sensory receptors.

-Anterior root fibers are efferent: they carry information from the spinal cord to the muscles

Anatomic Nervous System structure and function

regulating internal functions, contains sympathetic nervous system and parasympathetic nervous system

sympathetic nervous system

arouses the body for action (ex increases heart rate and blood pressure), mediates fight-or-flight response

parasympathetic nervous system

prepares body to rest and digest, reverses the fight-or-flight response

Enteric Nervous System structure and function

-a network of neurons embedded in the lining of the gastrointestinal tract

-controls bowel motility, secretion and blood slow to permit fluid and nutrient absorption and to support waste elimination

-the brain and ENS connect extensively through ANS, especially via the vagus nerve

ENS interacts with gut bacteria, known collectively as the ___________. Why is the blank important?

microbiome; microbiota influence nutrient absorption and are a source of neurochemicals that regulate physiological and psychological processes

Psychobiotics

live microorganisms used to treat behavioral disorders, thus microbiota can influence both CNS and ENS, leading to changes in behavior

What are the Ten Principles of the Nervous System?

1. The nervous system produces movement within a perceptual world the brain constructs

2. neuroplasticity is the hallmark of nervous system functioning

3. many brain circuits are crossed

4. the CNS functions on multiple levels (each evolutionary addition gives rise to more and more complex structures (and thus behaviors)

5. the brain is symmetrical and asymmetrical (yes, despite what you learned)

6. brain systems are organized hierarchically and in parallel (subsystems of the brain are organized into multiple parallel pathways, yet our conscious experiences are always unified)

7. sensory and motor divisions permeate the nervous system

8. the brain divides sensory input for object recognition and motor control

9. brain functions are localized and distributed

10. the nervous system works by juxtaposing excitation (increased neural activity) and inhibition (decreased neural activity).

Structures atop the brain or a structure within the brain are:

a) dorsal

b) medial

c) ventral

d) lateral

a

Soon after experiencing a stroke, Jim experiences difficulty with directing movements toward objects. The stroke is most likely to have occurred in his:

a) occipital lobe

b) parietal lobe

c) temporal lobe

d) frontal lobe

b

The somatic nervous system includes the _____, whereas the autonomic nervous system includes the _____.

cranial nerves and spinal nerves; sympathetic and parasympathetic divisions