chapter 1: neuroanatomy

neurons

nerve cells, human nervous system contains over 100 billion neurons, information processing unit of the nervous

system, specialized for precise

communication throughout the body

glial cells

support cells in the nervous system in which different types of glial cells perform distinct

roles in the nervous system

nucleus

contains DNA, the genetic code that

makes you, you, DNA is translated to

RNA, which leaves the nucleus through a process called transcription

ribosomes

makes proteins through translation, reads mRNA and translates into proteins, essential structures for cellular function

mitochondria

the powerhouse of the cell." ATP

(cellular energy) is produced through

cellular respiration

transcription

the process by which DNA is copied into RNA

translation

the process by which mRNA is used to create proteins

DNA

genetic information stored in every cell, cells differ because they express different genes and thus create different proteins

dendrites

neural input region that receives information

from other neurons, branch-like structures

soma (cell body)

integrates information coming from dendrites; houses basic cellular architecture (nucleus, etc.), big role in electrical communication, regulates cell function, integrates information from all dendrites by summing the electrical signals generated there

axon

long projection leading away from the soma,

information integrated by the soma is relayed down the axon, primary output communication that carries action potential

axon terminals

the very end of the axon, contacts

the dendrites of other neurons to pass information along, electrical to chemical communication

neuron communication

all about energy transfer between neurons, electrical potential energy is stored in the neuron via an ion concentration gradient (negative) and chemical potential energy is stored in the neuron in the form of

neurotransmitters

dendritic spines

short outgrowths on dendrites that increase the surface area available for synapses which leads to more input from other neurons

axon hillock or initial segment

site of action potential initiation, beginning of the axon

myelin sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

nodes of ranvier

gaps in the myelin sheath, action potential can jump between

axon collaterals

side branches of the axon

synapses

tiny gaps between dentrites and axon terminals of different neurons, neurotransmitters are released here, synapses detect calcium which triggers synaptic vesicles to move toward presynaptic membrane

presynaptic membrane

part of the axon terminal that releases the neurotransmitter

postsynaptic membrane

part of the target cell (often in the dendrites) that detects neurotransmitters

synaptic vesicles

membrane-bounded compartments in which synthesized neurotransmitters are kept

receptors

parts of the cell membrane that receive the neurotransmitter and initiate or prevent a new electric signal, specific proteins that control electrical state of postsynaptic membrane

Santiago Ramon y Cajal

established neuron doctrine which is the idea that the brain is comprised of neurons, made possible by the Golgi Stain

reticulum theory

idea that the brain was not

made up of cells, but was more like a giant net (no synapses or space between cells) advanced by Golgi himself

astrocytes

help form semi-permeable Blood Brain Barrier by contacting blood vessels, convey nutrients from the blood to neurons, help maintain homeostasis in the extracellular environment, minor role in cleaning up some extracellular debris

oligodendrocytes

create myelin that wraps around axon inside the brain and spinal cord, central nervous system

schwann cells

create myelin that wraps around axon outside the brain and spinal cord, peripheral nervous system

microglia

protect the brain by scavenging for pathogens, damaged cells, and other debris, acts as brain's mini immune system

resting state

cell bodies remain still while the branches move around, surveying the area

reactive state

once a threat is detected, they change their shape to engulf and destroy the danger

ependymal cells

form the barrier around ventricles and

channels containing cerebrospinal fluid (CSF), contain Cilia, hairlike projections that can move to help CSF flow

anterior

front side of the body

posterior

back side of the body

superior

top, toward the head

inferior

bottom, away from the head

medial

toward the midline, center

lateral

away from the midline, more towards outside

ipsilateral

same side, same side as thing being studied

contralateral

opposite side, opposite side as thing being studied

dorsal

toward the back

ventral

toward the stomach

coronal

divides the body into slices from front to back

sagittal

divides body into left and right

horizontal

side to side, top to bottom

central nervous system

consists of the brain and spinal cord

peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body

nerves

bundles of axons in the PNS

ganglia

clusters of cell bodies in the PNS

spinal nerves

31 pairs of nerves arising from the spinal cord

cranial nerves

12 pairs of nerves that carry messages to and from the brain, control sensory and motor factors for your face

motor nerves

control muscles, information flow is efferent (away from the CNS)

sensory nerves

convey sensation to the CNS, information flow is afferent (toward the CNS)

dorsal root ganglia

contain the somas of specialized neurons that conduct sensory info from PNS to CNS, send information toward spinal cord

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles, sensory and motor information

autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs

sympathetic nervous system

controls "fight-or-flight" response, tells organs & tissue to burn metabolic

energy, high adrenaline, requires action

parasympathetic nervous system

controls "Rest & Digest" response, tells organs and tissue to conserve metabolic energy, maintains essential life functions

enteric nervous system

nervous system regulating the gut microbiome, good gut health = good nervous system health

meninges

multilayered, fluid-filled sack which has protective membranes that surround the brain and spinal cord, consists of dura mater, arachnoid mater, subarachanoid space, and pia mater

subarachnoid space

contains cerebrospinal fluid, allows the brain to float

ventricles of the brain

open spaces/canals in the brain that contain cerebrospinal fluid

lateral ventricles

ventricles located in each cerebral hemisphere that produce CSF

third and fourth ventricles

CSF flows through and circulates here to the spinal cord

theory of localization

Franz Joseph Gall proposed that different parts of the brain carry out distinct functions

phrenology

belief that the shape of the skull reflected the shape of the brain, believed that by measuring the skull, one could understand things about a person's psychology

neural system

a population of neurons that communicate

across the boundaries between brain regions, communication between different lobes

neural circuit

a population of neurons that communicate within a brain region or between immediately

adjacent brain regions

forebrain

largest part of the brain, containing the cerebral cortex, the thalamus, and the limbic system, among other structures

cortex

plays a crucial role in many cognitive processes, including perception & decision making, wrinkly exterior of the human brain

gyri (gyrus)

ridges of the cortex (hills)

sulci (sulcus)

shallow grooves of the cortex (valleys)

gray matter

made up primarily of cell bodies, dendrites, and unmyelinated axons

white matter

made of myelinated axons

corpus collasum

connects the right and left hemispheres of the brain and allows information to pass between them

frontal lobe

region of the brain responsible for executive function & motor control like attention, decision making, etc.

parietal lobe

region of the brain responsible for touch, proprioception (position of limbs in space), somatosensory etc.

occipital lobe

region of the brain responsible for vision, etc.

temporal lobe

region of the brain responsible for hearing, some cortical structures in learning and memory, etc.

neocortex

90% of human cortical surface area, made up of 6 distinct cell layers, differentiated by size, shape, density, and connections of the neurons in each, layer I is the most superficial, layer VI is the deepest

allocortex

10% of human cortical surface area, made up of 3 or 4 layers of cells, depending on region

lissencephalic

brains have a smooth cortex

gyrencephalic

brains have a wrinkly cortex

basal ganglia

technically nuclei, not ganglia, located deep within the forebrain, beneath the cortex,

critical for initiating voluntary movement, dopamine reading center (processing)

limbic system

highly interconnected group of structures is important for functions such as emotion & memory, includes hippocampus and amygdala

hippocampus

limbic region crucial for remembering the events of your life, integration of new memories

amygdala

an area crucial for emotion & emotional memory, attachment of feelings and emotions to certain memories

thalamus

a cluster of nuclei at the center of the

forebrain, directs sensory information of all types to cortex, smell does not get directed

hypothalamus

cluster of nuclei with many functions,

including regulating energy intake and control of the endocrine (hormonal) system via the pituitary gland, so-called master gland of the endocrine system, regulating homeostasis/bodily functions

midbrain

relatively small region in humans, but still plays a key role, made up of tegmentum & tectum

tegmentum

contains neurons that produce

the neurotransmitter dopamine, sending

projections to the basal ganglia and cortex

tectum

processes audio/visual information

& controls orientation responses

hindbrain

division of the brain located at the base of the brain containing the medulla, pons, and cerebellum

medulla

controls heartbeat and breathing, outgrowth of the spinal cord containing nuclei that give rise to the cranial nerves, life-support systems

pons

connects the rest of the brain to the cerebellum; also contains nuclei that give rise to cranial nerves

cerebellum

the "little brain" at the rear of the brainstem; functions include precise control of motion