neuroanatomy

psyc 301

gray matter

darker patches on the brain composed of cell bodies of large neurons and the entirety of small neurons

white matter

composed of branches of the neurons, light because of the glia (myelin)

nissl staining (cresyl violet)

reveals gray matter

fiber staining

binds to myelin and reveals white matter

Golgi stain

stains about 10% of neurons but they take it through the entire cell, how we learned what a neuron was

projection neurons

neurons with long axons that go to another brain area

interneurons

neurons with short axons that only go to same or nearby brain areas, they modify signals

glial cells

non-neuronal cells in the CNS, in thee embryo they act as scaffolding for neurons

blood brain barrier

keeps everything bad out of the brain but also keeps out the immune system which is why the brain uses microglia

microglia

the immune system of the brain, they detect information on whether there’s something in the brain that shouldn’t be there, when they detect suspicious things they grow into their prime state, and when they absorb it they’re in their activated state

Schwann cell

glial cells in the PNS that wrap around the axon to become the myelin

oligodendrocytes

glial cells that have several branches coming out of their body and myelinate several axons in the CNS

astrocytes

glial cells that wrap around blood vessels (capillaries), ½ of the blood brain brain barrier and all of the nutrients that the brain needs comes through them

glial network

the proteins on astrocytes that causes them to click together (gap junctions) that buffer ions

gliotransmitters

chemicals released from the astrocytes that engulf the synapse and send signals to the neurons

DNA

a code for creating protein (a big string of amino acids that folds itself into a particular shape)

ATP

molecule in the brain that stores energy, mitochondria needs oxygen and carbohydrates to make it

cytoskeleton

helps structural stability and transport in cells

synapse

the gap between two neurons, can be from axon to blood (releases hormones), axon to extracellular fluid, and axon to axon

dendritic spines

protrusions on the dendrites that allow for modifiability of neural communication

central nervous system (CNS)

the brain and the spinal cord

peripheral nervous system (PNS)

the nerves all around the body except brain and spinal cord, includes the somatic and autonomic NS

afferent SNS

sensory, brings in sensory information from outside

efferent SNS

motor, carries motor commands from the CNS to the rest of the body

autonomic NS

regulates involuntary physiological processes

efferent ANS

sympathetic and parasympathetic NS, visceromotor responses

sympathetic NS

fight or flight, it frees up energy so we can create more ATP for the things we need more, ex. airways dilate to bring more oxygen, heart pumps more blood

parasympathetic NS

rest and digest, it stores energy for future use by converting them into other things such as fats

nuclei

cell clusters in the CNS (basal ganglia is named wrong)

ganglia

cell clusters in the PNS

nerves

bundles of axons outside CNS, considered fibres

tracts

bundles of axons in CNS, considered fibres

neuraxis

the imaginary line that places the brain at the front and tail at the back

coronal section

brain is cut into a front and back section

horizontal section

brain is cut into top and bottom

mid-sagittal section

brain is cut directly down the medial line, right and left side

telencephalon

most anterior part including the cerebral cortex and some underlying structures

diencephalon

the caudal part of forebrain, includes the thalamus and hypothalamus

thalamus

many nuclei that receive and send input from sensory systems, cerebellum, and basal ganglia

damage to thalamus

causes a loss of senses and even loss of consciousness

hypothalamus

collection of nuclei that direct the pituitary gland. They have diverse functions such as sex, aggression, feeding, sleep, parenting, etc… these neurons also act as a light switch that keep us awake or asleep

damage to hypothalamus

causes narcolepsy, pathological eating (more rare)

mesencephalon

midbrain, composed of tectum (roof, actually at the back) and tegmentum (floor, front)

tectum

responsible for the automatic orientation of our body towards sensory information

colliculi

two pairs of bumps in the tectum that are responsible for automatic orienting of our body toward sensory information, outside of our conscious access

damage to colliculi

not very common such as parinaud’s syndrome, leads to trouble with orienting

tegmentum

part of brainstem (mesencephalon) that houses Ventral tegmental area (VTA), Periaqueductal gray (PAG), Reticular formation, Red nucleus, Substantia nigra, and many fibres

periaqueductal grey

responsible for automatic defensive behaviours such as pushing, screaming, jumping, and receives most of its input from the amygdala

dopamine producing regions

substantia nigra and VTA

red nucleus

in animals, species specific behaviours like barking or meowing. In humans, not a huge role except in babies when they crawl and our arms swinging when we walk

dysfunction in red nucleus

sometimes caused by schizophrenia meds and leads to people twitching

loss of substantia nigra

leads to Parkinson’s disease

metencephalon

part of hindbrain, composed of pons and cerebellum

pons

large white matter bulge continuing from spinal cord/medulla

cerebellum

10% of brain volume and more than 50% of the neurons, critical for unconscious motor coordination

cerebellum damage

having to consciously coordinate movement, as well as alcohol affecting it first so body coordination becomes hard

myelencephalon

part of hindbrain, includes the medulla and reticular formation

medulla

has a lot of efferent like an extension of the spinal cord, has the most important nuclei that control involuntary life sustaining functions

damage to medulla

can be fatal and doctors will refuse to perform surgery here, overdose on alcohol can be life threatening because it acts on it

reticular formation

about 100 nuclei that run from myelencephalon to mesencephalon, critical for arousal, wakefulness, attention, sleep

damage to reticular formation

causes major disruption to life (coma) or can be fatal

longitudinal fissure

separates the cerebrum into two hemispheres

corpus callusom

the largest commissure between the two hemispheres

callosotomy

disconnecting the hemispheres as a treatment for epilepsy to prevent seizures from spreading across the brain

contralateral organization

the left and right hemisphere govern the right and left side of the world respectively

central fissure

separates the frontal lobe from the parietal lobe

pre central gyrus

the primary motor cortex that sends signals to the spinal cord to control muscles

lateral fissure

primary somatosensory cortex, separates the temporal lobe from frontal and parietal

layer 4

the main input cortical layer, if there’s a significant amount it means that the region is probably a sensory region

layer 5

output cortical layer, if there’s a significant amount it means that the region is probably a motor region

brodmann layers

different segments of the cerebral cortex based on their cortical layers that have different functions

limbic system

a bunch of individual structures rather than a system, commonly agreed that amygdala, HTh, mammillary body, hippocampus, fornix, cingulate cortex, septum, olfactory are included in it

amygdala

latin for almond because of its shape, the emotion centre

hippocampus

important for the formation of long term memory and spatial learning

cingulate cortex

plays a role in autobiographical memories

basal ganglia

nuclei that form a circuit that is critical in movement, skills, habits, and decision making, including striatum, globus pallidus, subthalamic nucleus

ventral striatum

nucleus accumbens in rats, plays a huge part in addiction

internal carotid

a pair of major arteries going to the brain in front

vertebral artery

a pair of major arteries going to the brain from the spinal cord

how the BBB protects

capillaries are pushed together (tight junctions) to prevent anything from slipping in and out of blood vessels, astrocytes wrap around the brain, and specialized proteins transport large molecules

meninges

a series of layers that are wrapped around the brain

dura mater

the tough outermost layer of meninges that protects the brain

arachnoid mater

a thin meninges that covers the cerebrospinal fluid

pia mater

innermost meninges, thin and transluscent

cerebrospinal fluid (CSF)

a major way for removing wastes from the brain and works as protection by slowing down how fast the brain moves in the brain if there’s impact on our skull, like an airbag

lateral ventricles

responsible for constantly making CSF that flow to 3rd and 4th ventricles and wrap around the brain and go down spinal cord

hydrocephalus

when passageways get blocked and CSF can’t get out which builds up pressure that damages the brain over time, brain tissue shrinks and ventricles widen

hydrocephalus treatment

an artificial tube called a shunt drains the CSF, a standardized surgery usually done early in life