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A&P Chapters 12-13
Nervous tissue, neurophysiology, spinal cord, spinal nerves and spinal reflexes
Term | Definition |
---|---|
Nervous system | includes all neural tissue in the body |
Two kinds of cells in neural tissue | neurons, neuroglia |
Neuron | a cell that sends and receives signals; basic functional unit of the nervous system |
Neuroglia | cells that support and protect neurons |
Organs of the nervous system | brain, spinal cord, sensory receptors of sense organs, nerves |
Anatomical divisions of the nervous system | central (CNS), peripheral (PNS) |
Central nervous system | consists of brain and spinal cord; contains neural tissue, connective tissue, and blood vessels |
Functions of the CNS | process and coordinate: sensory data from inside and outside body, motor commands, higher brain functions |
Higher brain functions | intelligence, memory, learning, emotion |
Peripheral nervous system | includes all neural tissue outside the CNS |
Functions of the PNS | deliver sensory information to CNS, carry motor commands to peripheral tissues and systems |
Nerves | bundles of axons with connective tissue and blood vessels that carry sensory information and motor commands in the PNS |
Cranial nerves | nerves that connect to the brain |
Spinal nerves | nerves that connect to the spinal cord |
Functional divisions of the PNS | afferent, efferent |
Afferent PNS | carries sensory information from PNS receptors to CNS |
Efferent PNS | carries motor commands from CNS to muscles and glands innervated by PNS |
Receptors of afferent PNS | composed of neurons and specialized cells; detect changes or respond to stimuli; also found in special sensory organs |
Effectors of afferent PNS | cells and organs that respond to efferent PNS signals |
Somatic nervous system | part of the efferent PNS that controls both voluntary and involuntary skeletal muscle contractions |
Autonomic nervous system | controls subconscious actions, such as contractions of smooth muscle and cardiac muscle, glandular secretions; made up of the sympathetic and parasympathetic divisions |
Sympathetic nervous system | division of the ANS that has a stimulating effect (fight or flight) |
Parasympathetic nervous system | division of the ANS that has a relaxing effect (rest and digest) |
Major organelles of the neuron cell body | Large nucleus/nucleolus, perikaryon (cytoplasm), mitochondria, RER and ribosomes, cytoskeleton, Nissl bodies, dendrites, axon |
Components of the neuron cytoskeleton | neurofilaments, neurotubules, neurofibrils |
Neurofibril | bundle of neurofilaments that provides support for the dendrites and axons |
Nissl body | dense area of RER and ribosomes that makes neural tissue appear gray |
Dendrite | highly branched protrusion of neuron |
Dendritic spines | many fine processes branching off a dendrite that receive information from other neurons; represent 80-90% of neuron surface area |