unit 1 - intro to neuroanatomy

constructive brain

- our brains “construct” the reality we perceive around us
- we might see things that aren’t really there because the brain expects the world to be set up a certain way based on all the experiences we had from a young age

cafe wall illusion

alternated lines of black and white squares made to look like the lines are slanted, when in fact, they are actually parallel lines
- demonstrates effect of image processing occuring at the retina combined with primary visual cortex

gyrus

a ridge of cerebral cortex

sulcus

a valley of cerebral cortex

cortical sheet

the outer, surface covering of cerebral cortex, composed of gray matter (neuron cell bodies)

cerebral cortex

the large, folded part of the brain that sits above the cerebellum and brainstem, made up of gray and white matter

cerebellum

(Latin for "little brain") the small, highly rigid portion of brain that sits inferior to the cerebral cortex and posterior to the brainstem

anterior

towards the front of the brain

posterior

towards the back of the brain

superior

towards the top of the brain

inferior

towards the bottom of the brain

lateral

the lateral view of the brain would show the surface of a cerebral hemisphere under the ears

medial

the medial view of the brain would be the inner surface of a cerebral hemisphere

dorsal

towards the top of the brain (towards the back surface of the body in the brainstem & spinal cord)

ventral

towards the bottom of the brain (towards belly surface of the body in the brainstem & spinal cord)

rostral

towards the front of the brain (towards the top surface of the body in the brainstem & spinal cord; rostral means "beak")

caudal

towards the back of the brain (towards the bottom surface of the body in the brainstem & spinal cord; caudal means "tail")

sagittal

a vertical slice of the brain cut down the center, from anterior to posterior, giving a view from left or right

coronal

a vertical slice of the brain cut from superior to inferior, giving a view from the front or back of the brain

axial

a horizontal slice of the brain cut from left to right, giving a view from the top or bottom of the brain

central nervous system

composed of the brain and spinal cord

peripheral nervous system

composed of peripheral nerves that connect the CNS to the limbs, trunk, and internal organs

autonomous nervous system

a subdivision of the PNS that controls visceral functions; includes parasympathetic and sympathetic nervous systems

parasympathetic nervous system

maintains rest

sympathetic nervous system

prepares for action

cranial nerves

a set of 12 specialized nerves that act as the PNS (motor control and sensory info) to the head and neck 

meninges

the three protective layers of tissue between the brain and the skull
* CNS: within | PNS = outside

dura mater

the durable, leathery outer protective layer of the meninges

arachnoid mater

the spider web-like middle protective layer of the meninges that is filled with cerebral spinal fluid

pia mater

the thin, shiny, inner protective layer of the meninges that "shrink wraps" the brain

frontal lobe

the anterior portion of cerebral cortex, involved in emotion, cognition, and executive control

parietal lobe

the superior posterior portion of cerebral cortex, superior to the occipital and temporal lobes, posterior to the frontal lobe

temporal lobe

the inferior portion of cerebral cortex, anterior to the occipital lobe and inferior to the others

occipital lobe

the posterior portion of cerebral cortex, primarily involved in vision processing

central sulcus

the sulcus dividing the frontal and parietal lobes, surrounded on each side by motor and sensory cortex

lateral fissure

the gap that divides the temporal from the frontal and parietal lobes; aka the name for a large sulcus

parieto-occipital sulcus

the sulcus that divides the parietal and occipital lobes

preoccipital notch

the notch that serves as the bottom point of the imaginary dividing line between the temporal and occipital lobes; the top of the parieto-occipital sulcus is the top point

brodmann’s areas

~50 cytoarchitectural areas defined by neuroanatomist Brodmann according to cell size, cell density, number and thickness of cortical layers, and density of myelinated axons; numbering system is becoming less common as neuroimaging measurements take over tissue histology

gray matter

outer ‘bark’ of the cerebral cortex composed of neuronal cell bodies (neurons); this is where computations happen; much of cortex consists of six layers
* each layer has different neuron types, thickness, function

white matter

inner region of cerebral cortex composed of the axons of the neurons with cell bodies in the gray matter; axons can be thought of as the ‘wiring’ connecting different regions of gray matter

neuron

the basic cell in the brain that processes and transmits information in the form of electrical and chemical signals

dendrite

branched portion of a neuron which receives inputs from synapses with other cells and sends small depolarizations towards the cell body

cell body

the "main" portion of a cell that contains the nucleus, mitochondria, and other organelles necessary for the cell to survive

axon hillock

base of the axon, where it meets the cell body of the neuron; action potentials are initiated here

axon

the long cell structure that carries depolarizations (action potentials) away from the cell body of a neuron to the synapse

Node of Ranvier

the small gaps between myelin sheaths in myelinated axons involved in fast action potential propagation down the axon

synapse

the region/space which information flows across from one neuron to another neuron; space between neurons can be called the synaptic cleft

axon terminal

the very end of a branch of a neuron’s axon, specialized to release neurotransmitters from vesicles into the synapse in response to an action potential

glial cell

surround neurons in CNS and PNS and provide myelination as well as other support for them; most abundant cell types in CNS. types differ between:

• CNS: oligodendrocytes, astrocytes, ependymal cells, microglia (not prone to recovery after injury; blocks its own regrowth as a way to keep brain circuits intact and to keep them from changing in adult brain; don’t want to keep rewriting experiences and memories all the time)

• PNS: satellite cells, Schwann cells (allows axons to grow back after injury)

myelin sheath

a layer of protective tissue wrapped around axons of neurons to hasten the transmission of action potentials

neuronal communication

electrical conduction (action potential) along the axon and chemical transmission via neurotransmitter release at the synapse