Neuro Test 1

What is The Brain Theory?

the brain is the source of all behavior

brain abnormalities often underlie communication disorders

What is The Neuron Theory?

the unit of brain structure and function is the neuron

What is the brain?

- composed of two symmetrical hemispheres

- inner hollow tube filled with cerebrospinal fluid (CSF)

- outer later of wrinkled tissue knows as cerebral cortex (aka neocortex)

What connects the two hemispheres?

• Hemispheres are connected by commissures, the largest is the corpus callosum (corpus callosum = a big band of fibers (axons))

Brain is an old English word for what?

Tissue around skull

What is CSF? Where does it sit?

• CSF sits in middle with hemispheres on sides, essentially salt water, is around and in hemispheres

What are ventricles important for?

Localization

What are the features of the neocortex? Why are these important?

- very large, increases surface area, means more neurone which means more information

- more wrinkles = good information processing

- packed in closer means faster communication between neurons

What are gyri(plural)/gyrus(singular)?

Folds of the cortex

What are sulci(plural)/sulcus(singular)?

Creases between the folds

What is a large sulci called? What are 2 examples?

Fissure

ex: longitudinal or lateral fissure

What are the four lobes of the brain?

frontal, parietal, occipital, temporal

What are the three divisions of the CNS? What develops first?

Forebrain, Brainstem, Spinal Cord

Spinal cord develops first

What is the function of the forebrain?

• Performs higher functions like speaking, thinking, planning, remembering and perception

What is the function of the brainstem?

performs regulatory and movement producing functions

What is the function of the spinal cord?

performs regulatory and movement producing functions

lowest level of processing

What is the difference in tissue from the CNS to PNS?

Tissue in the CNS does not regenerate after damage, whereas tissue in the PNS can regenerate after damage

What is the PNS composed of? What is its function?

Spinal and cranial nerves

Fibers that carry information to and from the CNS

What are the two divisions of the PNS?

Somatic and Autonomic Nervous System

What is the somatic system composed of?

• Sensory Pathways: Collect information from the senses and send it to the cortex

• Motor Pathways: Nerve fibers that connect the brain and spinal cord to the body's muscles

What is the autonomic nervous system composed of?

• Sensory & motor pathways that control the internal organs such as the heart, lungs, and stomach

Who was Paul Broca? What did he do?

- Had patient who was only able to say "tan" with paralysis on the right side of the body

- At autopsy a lesion in the third convolution of the left frontal lobe was found

- Broca's Area

• Anterior speech region of the brain

• Broca's Aphasia

- Syndrome that results from damage to Broca's Area

What is a repetitive utterance?

- ex: patient who was only able to say "tan"

What is lateralization?

• Functions can be localized to one side of the brain (happens in 1 hemisphere)

What are 3 characteristics of neurons?

Neurons are discrete, they carry an electrical signal and communicate with each other via a chemical signal (neurotransmitter)

What do neurons do?

- Acquire information, process information, and act on information

What are the 3 major parts of the neuron?

cell body, axon, dendrites

What do glial cells do?

- Help neurons, hold them together

- Carry out supportive functions

- Some wrap around neurons, some around blood cells, some hold neurons in place (different types)

Are there more neurons or glial cells?

Glial cells

What is a synapse?

junction between two neurons

What does plastic synapses refer to? Who came up with it?

Donald Hebb

"Neuron's that fire together, wire together"

The brain is plastic and is constantly changing and reorganizing

What is rostral and caudal?

rostral means beak aka front

caudal means tail aka back

What is anterior and posterior?

Anterior (front), posterior (back)

ex: ex: frontal lobe is anterior to occipital lobe, Broca's area is in posterior of frontal lobe

What is dorsal and ventral?

dorsal (back) and ventral (front)

What is superior and inferior?

Superior = above

Inferior = below

What is lateral and medial?

Lateral is away from centre

medial is towards center

What is a coronal section/plane?

Cut the brain from top of head down

End up with whole frontal lobe in front half

What view does a coronal section give us?

Frontal view

What is a horizontal section/plane?

horizontal cut, like looking at brain from above

What view does a horizontal section give us?

Dorsal view

What is a sagittal section/plane?

Cut straight down corpus callosum

get two even halfs

What view does a sagittal section give us?

Medial view

How does the orientation of the terms switch from brain to spinal cord?

Rotate 90 degrees

Ex: Ventral is down for head, but towards stomach for spinal cord

Structures on the same side are?

Ipsilateral

Structure on the opposite side are?

Contralateral

Structures that lie in both hemispheres are?

Bilateral

Structures that are close together are?

Proximal

Structures that are far apart are?

Distal

What are efferent pathways?

• Pathways that go away from brain structures (think e = exit) ex: motor pathway

What are afferent pathways?

Pathways that go toward brain structures (think a = approach) ex: sensory pathway

What protects support/protection for the brain?

Skull

Meninges

What are the meninges?

- Three layers of membranes inside the skull and vertebrae

- dura mater, arachnoid membrane, pia mater

What does the subarachnoid space do?

Web like protrusions sit in this space and act as valves between CSF and blood

How is the CNS protected?

- Cushioned by the cerebrospinal fluid (CSF) that continuously circulates

- Protected from body chemicals by blood-brain barrier (tight junctions between blood vessel cells)

What supplies blood to the brain?

Two internal carotid arteries and two vertebral arteries

These connect at the base of the brain and branch off into 3 arteries

What are the 3 arteries that branch to supply blood to the brain?

- Anterior Cerebral Artery

- Middle Cerebral Artery (blockage here = stroke = aphasia)

Posterior Cerebral Artery

What is a stroke?

- Interruption of blood flow to the brain that kills brain cells

What is ischemia?

deficiency of blood flow to the brain

What is a hemmorhagic stroke?

burst of a blood vessel

How do neurons and glia cells develop?

1. start as neural stem cells: undifferentiated and have the capacity for self-renewal

2. progenitor cells develop from stem cells and give rise to blasts, primitive types of nervous system cells

3. blasts develop into neurons or glia

What are 3 neuron types?

sensory, motor, interneurons

What are 5 types of glial cells?

1. Schwann Cells.

2. Oligodendrocytes.

3. Astrocytes.

4. Microglia.

5. Ependymal cells.

What do ependymal cells do?

produce & secrete cerebrospinal fluid

What do astrocytes do?

nutritive support and function

What do microglial cells do?

defensive function

What do oligodendrocytes do?

forms insulating myelin around axons in brain and spinal cord (CNS)

What is gray matter?

a collection of neuronal cell bodies

in the cortex, this does hard work (where the information processes are)

gets its color from capillary blood vessels and neuronal cell bodies

What is white matter?

myelinated axons

white matter = axon bundles

gets its color from axons covered in an insulating layer of glial cells

What is the rose analogy?

Rose is the cortex, the stem is the axon bundles

What is a layer or nuclei?

- Large well-defined group of cell bodies

- Ex: lateral geniculate nucleus

- Nucleus means cell bodies packed together performing a specific function

What is a tract and where is it located?

- bundle of axons in the CNS

- Large collection of axons (white matter) projecting to or away from a layer or nucleus within the CNS

What are nerves? What does this tells us about the system were in?

- Nerve means you're in the peripheral nervous system (PNS)

- Fibers and fiber pathways within the PNS that enter and leave the CNS

- Examples: Auditory Nerve, Vagus Nerve

What are ventricles?

- fluid filled spaces in the brain

- hollow pockets filled with CSF

- ventricles are lined with glial cells that make CSF

How many ventricles are there? What shape are they?

- 4

- lateral ventricles (1st and 2nd) are C shape

- third and fourth ventricles extend into the brainstem and spinal cord (3rd is donut shape, 4th is tent shape)

What are ventricles helpful for?

Orienting you in the brain

Where does the diencephalon fit in?

Sometimes it is included in the forebrain, sometimes it is included as its own thing before the brainstem

Where is the spinal cord located?

vertebral canal

How many segments are in the spinal cord?

31 segments

What are the segments of the spinal cord?

8 cervical (top)

12 thoracic

5 lumbar

5 sacral

1 coccygeal (bottom)

Each segment has how many nerves?

A pair of spinal nerves

1 nerve each way

What do spinal nerves do?

- carry messages to and from the spinal cord

- carry sensory signals to the spinal cord

- carry motor signals away from the spinal cord

What does a mixed spinal nerve mean?

a spinal nerve carries both motor and sensory information

What is a dermatome?

specific segment of skin supplied by a single spinal nerve (not all regions are the same size)

How is gray and white matter organized in the spinal cord?

the white matter is on the outside, and the gray matter is on the inside (opposite of the brain)

What is the dorsal root?

- Strand of afferent fibers entering the spinal cord

- Brings sensory information from receptors

What is the ventral root?

- Strand of efferent fibers leaving the spinal cord

- Carries motor information to the body

What is the Bell-Magendie Law?

The entering dorsal roots carry sensory information to the brain & the exiting ventral roots carry motor information to the muscles and glands

What do cranial nerves do?

- Motor function for face, mouth, neck, top of shoulders

- Bring in sensory information

- Control touch for the head but also all other senses for whole body

How many cranial nerves are there?

12 pairs

Are cranial nerves sensory? Motor? Both?

Can have sensory, motor, or both

What is cranial nerve 1? Function?

Olfactory - smell (sensory)

What is cranial nerve 2? Function?

Optic - vision (sensory)

What is cranial nerve 3? Function?

Oculomotor - eye movement (motor)

What is cranial nerve 4? Function?

Trochlear - eye movement (motor)

What is cranial nerve 5? Function?

trigeminal - masticatory movements (the jaw) (both)

What is cranial nerve 6? Function?

Abducens - eye movement (motor)

What is cranial nerve 7? Function?

facial - facial movements (both)

What is cranial nerve 8? Function?

Auditory vestibular - hearing (sensory)

What is cranial nerve 9? Function?

glossopharyngeal - tongue and pharynx (both)

What is cranial nerve 10? Function?

vagus - heart, blood vessels, viscera, movements of larynx and pharynx (both)