Central Nervous System = brain and spinal cord

Peripheral Nervous System = all of the nerves, everything that is not the brain and spinal cord

There are 31 spinal nerves **

Nervous system cells are the neurons and their effectors (neurons, or muscle cells; smooth, cardiac, skeletal)

Nerve fibers are bundles of axons

There are 12 cranial nerves, check other note

A ganglion is a neuron cell body outside of the brain and the spinal cord???

A plexus is a network of axons (NTK brachial)

Glial cells are the supporting cells, they take care of the neurons

• Functions:

  • maintaining homeostasis

  • receives sensory input

  • processes sensory input and initiates response

  • controls muscles and glands

  • establishes and maintains mental activity (consciousness, thinking, memory, emotions, etc.)

Sensory =Afferent, AWAY from receptors

Motor =Effarent, TO the effector

Peripheral Nervous System (PNS):

• Somatic Nervous System controls skeletal muscle, 1 neuron system

• Autonomic Nervous System controls everything that is involuntary (digestion, breathing, urination, etc.), 2 neuron system

Sympathetic = excited, expending energy

Parasympathetic = at rest, brings body back to rest

The neuron cell body is called a soma, it has specialized rough ER (Nissl bodies) where protein synthesis occurs, meaning there are ribosomes; lysosomes clean up the cell

Axolemma is the plasma membrane of the axon

Axoplasm is the cytoplasm of the axon

The majority of neurons are multipolar (motor)

4 Types of Neuroglial Cells

• Astrocytes: provide structure for nervous tissue, GIVES STRUCTURE/FOUNDATION TO FORM THE BLOOD-BRAIN-BARRIER, produce chemicals that form tight junctions to filter out stiff in the blood that might harm the brain

• Epindymial: line brain ventricles and spinal cord central canals, the CHOROID PLEXUS (in all ventricles) secretes CSF

• Microglia: “garbage trucks,” macrophages, gets rid of waste by phagocytosis

• Oligodendrytes (Schwann cells): form the myelin sheath

Cerebrospinal Fluid comes from and goes back into the blood, why we need to be hydrated, because if not, blood gets more viscous

Myelinated axons are white matter

Unmyelinated axons are gray matter

Gates on dendrites are ligand, while gates in the axon are voltage

Neurons communicate by neurotransmitters, they need a ligand gated channel to bind to (ie ACh)