Nervous System Overview: Brain, Spinal Cord, and Cell Function

Somatic Senses

Touch, temperature, body position

Visceral Senses

Organ stretch, blood pressure, and blood chemistry

CNS

Brain and spinal cord, enclosed by bone, integration and processing center

PNS

Nerves and ganglia outside the brain and spinal cord, generally not enclosed by bone, carries info to and from the CNS

Neuraxis

Longitudinal axis of the CNS

Rostral

Toward the beak/nose (along neuraxis)

Caudal

Toward the tail (along neuraxis)

Dorsal

Toward the back (perpendicular to neuraxis & medial-lateral axis)

Ventral

Toward the belly (perpendicular to neuraxis & medial-lateral axis)

Telencephalon

Involved in perception, voluntary action, cognition, emotion, and memory

Frontal Lobe

Motor control, cognition, speech production

Parietal Lobe

Somatosensation, sensory integration

Temporal Lobe

Hearing, memory, language comprehension

Occipital Lobe

Vision

Cerebellum

'Little brain', important for coordination of movement, balance and posture, and motor learning

Vermis

In between two hemispheres, coordinate movements and maintain posture

Thalamus

Relays and regulates sensory and motor info to the cerebral cortex

Hypothalamus

Maintains homeostasis

Epithalamus

Contains pineal gland

Midbrain

Involved in vision, hearing, motor control, arousal, and motivation/reward

Pons

Relays info from cerebral cortex to the cerebellum to help coordinate movement

Medulla

Regulates vital functions, contains sensory and motor pathways between the brain and spinal cord

Gyri

Ridge/fold on the surface of the brain

Sulci

Groove in the brain surface

Fissure

Deep, major groove

Dura Mater

Outermost and thickest layer of the meninges

Arachnoid Mater

Middle layer of the meninges

Pia Mater

Innermost and thinnest layer of the meninges

Choroid Plexus

Produces cerebrospinal fluid (CSF)

Hydrocephalus

CSF blockage causing accumulation of CSF, compressing/damaging brain tissue

Blood Brain Barrier (BBB)

Formed by tight junctions between endothelial cells, controls movement of substances between blood and brain

mRNA

Used as template for synthesis of protein in cytoplasm

Transcription

Synthesis of mRNA from DNA in nucleus

Translation

Synthesis of protein from mRNA in cytoplasm

Ribosomes

Reads sequence of RNA to synthesize protein

Rough Endoplasmic Reticulum (ER)

Synthesis of membrane proteins and proteins for export

Nissl Substance

Large amounts of rough ER in neurons somas

Golgi apparatus

Made up of smooth ER, proteins are modified by enzymes and packaged into vesicles

Mitochondria

Generate energy for the neuron

Lysosomes

Formed from Golgi apparatus, contain enzymes for breaking down organelles and molecules for recycling

Cytoskeleton

Determine shape of cell, involved in cell movement and transport of molecules throughout the cell

Axonal Transport

Most of the volume of the neuron can be in the axon

Anterograde

Transport from soma to axon

Retrograde

Transport from axon to soma

Atrocytes

Homeostasis and support

Oligodendroglia

Produce CNS myelin

Microglia

Provide immune defense

Ependymal cells

Line ventricles

Satellite cells

Support neuronal activity

Schwann cells

Produce PNS myelin

Ions

Atom/molecule with a positive or negative charge

Ionic bonds

Atoms can loan electrons to their partner

Equilibrium

Ions want to move from area of high concentration to area of low concentration to equal out charge

Resting Membrane Potential

Higher concentrations of K+ inside the cell and lower concentrations of Na+ and Cl- in its cytoplasm than outside the cell

Graded potentials

Activation of neurotransmitter receptors causes changes in ions in dendrites and soma

Action Potentials

All or none event

Voltage gated Na+ channels

Generate Action Potential

Voltage gated K+ channels

Repolarize membrane

Depolarization

Voltage gated Na+ channels open (Na+ enters), causing Action Potential

Repolarization

Voltage gated K+ channels open (K+ out) and Na+ channels close

Hyperpolarization

K+ channels close slowly, causing charge to briefly become more negative

Neurotransmitter release

When Action Potential reaches synapse, it causes depolarization allowing voltage gated Ca+ channels to open

Ionotropic receptors

Ligand-gated ion channels, rapid and short lasting

Metabotropic receptors

G-protein coupled, slow and long lasting

Excitatory postsynaptic potential (EPSP)

Excitatory neurotransmitters result in depolarization of cell

Inhibitory postsynaptic potential (IPSP)

Inhibitory neurotransmitters result in hyperpolarized cell