A and P Final Exam Ch 11

Nervous system function

Nervous system function

Directs voluntary movement, seat of consciousness, personality, learning, and memory, regulates many aspects of homeostasis, vitals, sleep/wake cycle

Sensory input

Gathering information

Integration

Interpretation

Motor output

Response

Afferent

PNS - sensory input

Efferent

PNS - motor output

CNS contains

Brain and spinal cord

PNS contains

Nerves

Brain

Billions of nerve cells (neurons); protected by bones of skull

Spinal cord

Begins at foramen magnum; contains vertebral foramina of first cervical to first or second lumbar vertebra

PNS

All nerves in body outside protection of skull and vertebral column

Nerves

Axons of neurons bundled together with blood vessels and connective tissue; carry signals to and from CNS; classified by origin and destination

Cranial nerves

12 pairs of nerves traveling to or from brain

Spinal nerves

1 pair of nerves traveling to or from spinal cord

Cytoskeleton

Microtubules; structural support and chemical transportation between cell body and axon

Neurofibrils

Intermediate filaments of cytoskeleton; structural support extending into neuron processes

Axon hillock

Where axon originates from cell body

Axon collaterals

Branches extending from main axon

Telodendria

Small branches arising from axon and axon collaterals near where extensions end

Axon terminals

Arise from telodendria; components that communicate with target cell

Axolemma

Plasma membrane surrounding axon and its cytoplasm

Slow axonal transport

Transports substances from cell body through axon; rate of 1-3 mm/day

Fast axonal transport

Requires motor proteins and consumes ATP; vesicles and membrane-bound organelles travel back toward or away from the cell body; 200-400 mm/day

Receptive region of axon

Dendrites and cell body

Conducting region

Axon

Secretory region

Axon terminal

CNS cell bodies vs bundles of axons

Groups of neuron cell bodies are called nuclei, bundles of axons are called tracts

PNS cell bodies vs bundles of axons

Groups of neuron cell bodies are called ganglia, bundles of axons are called nerves

Sensory (afferent neurons)

Carry information towards the CNS; neuron cell bodies in PNS receive information from sensory receptors and relay information via axons to brain or spinal cord; usually pseudo unipolar or bipolar

Interneurons (associations) neurons

Relay information within the CNS between sensory and motor neurons; most neurons in the body; multipolar; communicate with many other neurons

Motor (efferent) neurons

Carry information away from cell body in CNS to muscles and glands; mostly multipolar

Schwann cells

Myelination in the PNS

Satellite cells

Flat cells that surround and support cell bodies

Neuroglia

Supportive roles for neurons, can divide and replace areas of damage, four different types in CNS

Astrocytes

Star-shaped cells that provide structural support by anchoring neurons and blood vessels, connected to other astrocytes by gap junctions, clean up excess K and neurotransmitters, facilitate blood brain barrier

Brain cancer

Most brain cancers arise from mutated neuroglial cells called gliomas

Microglia

Immune cells in the CNS, activated by injury and phagocytic cells, smallest glial cell

Ependymal cells

Line cavities, cilia circulate fluid around the brain and spinal cord, some cells secrete cerebrospinal fluid

Oligodendrocyte cells

Send out arms that wrap around the axons of multiple neurons, cells generate myelin sheath in the CNS

Cerebrum function

Structure responsible for higher mental functions, interprets sensory stimuli, plans and initiates movement

Diencephalon function

Processes, integrates, and relays information, maintains homeostasis, regulates biological rhythems

Cerebellum function

Monitors and coordinates movement

Brain stem function

Maintains homeostasis, controls certain reflexes, monitors movement, integrates and relays information