Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior Flashcards
Neuron Doctrine
The brain is composed of independent cells that are distinct structurally, metabolically, and functionally
Info is transmitted from cell to cell across synapses
Neuron has structures in common with other cells
Mitochondria– produce energy
Golgi apparatus– packages cellular materials for transport
Ribosomes– translate genetic instructions into proteins
Four principle subdivisions of neurons
Input zone, integration zone, conduction zone, output zone
Input zone
The cell body and dendrites receive info via synapses from other neurons
Integration zone
Where the decision to produce a neural signal is made
Conduction zone
The axon carries the neuron’s own electrical signal away from the cell body to the axon terminals
Output zone
Axon terminals transmit the neuron’s signals across synapses to other cells
Motoneurons
Motor neurons
Stimulate muscles or glands
Sensory neurons
Respond to environmental stimuli (light, smell, touch, etc.)
Interneurons
Receive input from and send input to other neurons
Glial cells
They support and assist neurons
Provide neurons with raw materials
Alter neuron structure and excitability
4 types of glial cells
Astrocytes
Microglia
Oligodendrocytes
Schwann cells
Astrocytes
Star-shaped cells
Receive neuronal input and monitor neural activity
Regulate blood flow
Form new synapses and prune old ones
Microglia
Small but active
Two functions:
House-keeping: remove debris from injured or dying cells
Immune function: primary immune cells in the brain, produce and release cytokines in response to sickness
Oligodendrocytes
Provide myelination in the central nervous system
Schwann cells
Provide myelination in the peripheral nervous system
Myelination
Fatty insulating substance to increase speed of signal
Nodes of Ranvier
Gaps between sections of myelin where the axon is exposed
And where voltage-gated ion channels are located
Gross neuroanatomy
Features of the nervous system visible to the naked eye
Central nervous system (CNS)
Brain and spinal cord
Peripheral nervous system (PNS)
Motor nerves
Sensory nerves
Two nervous systems
Somatic nervous system: brain and spinal cord, voluntary movement
Autonomic nervous system: regulates involuntary bodily functions
Somatic nervous system
Cranial nerves: head and neck
Spinal nerves: dorsal (body to spinal cord) and ventral roots (spinal cord to muscles)
Spinal cord and spinal nerves
Cervical: neck
Thoracic: trunk
Lumbar: lower back
Sacral: pelvic
Coccygeal: bottom
Autonomic nervous system
Sympathetic neurons: fight or flight
Parasympathetic neurons: rest and digest
Cerebral cortex
Thick, outermost layer of the cerebral hemispheres comprised mostly of neuronal cell bodies, dendrites, and axons
Inside the brain
Gray matter: cell bodies
White matter: axon tracts
There are several brain regions within each lobe
Cortical columns
In the cerebral cortex
Each column serves as a unit to process information
How do cortical regions communicate?
Via axon tracts
Nissel stain used to identify only cell bodies
Golgi stains used to idenitfy the entire neuron
Cerebellum
Motor learning and coordination
3 layers:
Parallel fibers: outer layer
Purkinje cell layer: middle layer
Granule cell layer: inner layer
Meninges
Protective membranes of brain and spinal cord
Dura mater: tough outer layer
Arachnoid: middle layer, CSF
Pia mater: delicate inner layer
Ventricular system
Series of chambers filled with CSF
CSF: acts as a shock absorber and provides nutrients to the brain
Lateral ventricle
Extends into all 4 lobes
Lined with choroid plexus that produces CSF
Vascular system
Provides brain with oxygen
Hemorrhagic stroke
Rupture in artery causes blood to leak into the brain
Ischemic stroke
Clots prevent blood from reaching region of the brain, causing it to die
Glymphatic system
Important for draining waste from the brain
Providing flow of cerebrospinal fluid to the brain and helping clear debris from that area
In Alzheimer’s patients, waste builds up, and this system has a hard time clearing it out
Axon hillock
Orange halo around the part of the cell body that makes the decision if the axon is going to fire
Axon collaterals
Axon terminals
Axonal transport
Motor proteins that carry stuff back and forth
Anterograde transport: sending supplies/info from the cell body to the terminals
Retrograde transport: taking info from axon terminals and sending it to the cell body
