111 terms

A & P 1551 - Nervous Tissue & The Spinal Cord and Spinal Nerves-College of Dupage

College of Dupage: A & P 1551; Skarbek; Chapters 12 & 13 (Principles of A & P, 12th edition, Tortora)
Three functions of Nervous System:
Sensory, integrative & motor function
Sensory Function:
sensory receptors that detect stimuli
Integrative function:
Processing of information
Motor function:
carries out the responses
Two divisions of Neverous system:
Central and Peripheral Nervous Systems
Central nervous system:
Made up of brain and spinal cord
Peripheral Nervous system:
all nervous tissue outside the central nervous system; two catagories
Two categories of Peripheral Nervous system:
Somatic and autonomic nervous systems
Somatic nervous system:
mostly responsible for voluntary functions; skeletal muscles
Autonomic Nervous System:
involuntary automatic functions; heart, digestion, respiration; to subdivisions
Two subdivisions of autonomic nervous system:
Sympathetic and parasympathetic divisions
one nerve cell
Cell body:
Part of neuron that has nucleus, cytoplasm and typical organelles
part of neuron-projections that send messages to the cell body
part of neuron-long projection that sends messages away from cell body; every neuron has one one "of these"
Axon terminals:
part of neuron-branches at end of axon
Synaptic end bulbs:
part of neuron-bulb shaped structures filled with neurotransmitters
a type of neuroglia of CNS that physically protects neurons ; plays role in learning and memory
a type of neuroglia of CNS; responsible for productin the myelin sheath
a type of neuroglia of CNS; phagocytes that help fight foreign substances
Ependymal Cells:
a type of neuroglia of CNS; produce cerebrospinal fluid; helps with circulation
Schwann cells:
type of neuroglia of PNS; cells that surround axons
Satellite cells:
type of neuroglia of PNS; provides structural support; involved with nutrient exchange between cells and interstitial fluid
Two types of neuroglia that produce myelin sheaths:
Schwann cells and oligodendrocytes of CNS
Myelin sheath:
A multi-layered lipid and protein covering that surronds axons
the outer nucleated cytoplasmic layer of the schwann cell, which encloses the myelin sheath
Nodes of ranvier:
gaps in myelin sheath that occur between schwann cells; increases nerve signal transmission
white fatty substance produced by oligodendrocytes and schwann cells
Potassium ion:
Sodium ion:
Ion channels:
4 types of chanels that allow ions (K+ and Na+) to pass in and out of a cell
Electrochemical gradient:
Ions move from areas of higher concentration to areas of lower concentration
Resting membrane potential:
an excess of unused ions that store potential energy, that line the outer wall of the plasma membrane
Unequal distribution of ions in Extra Cellular Fluid & Cytosol:
contributes to resting membrane potential; plasma membrane has more K+ leakage channels that allow for more K+ to diffuse down concentration gradient out of cell into ECF
Inability of anions to leave cell:
contributes to resting membrane potential because they are attached to nondiffusible molecules such as ATP
Electrogenic nature of Na/K ATPases:
contributes to resting membrane potential by pumping out Na+ as fast as it leaks in
The two main phases of an action potential:
depolarizing and repolarizing phases
Depolarizing Phase:
negative membrane potential becomes less negative, reaches 0, then becomes positive
Repolarizing Phase:
membrane potential is restored to resting state
Refractory period:
perior of time after action potential when another impulse can not be generated
Two types of propagation of nerve impulses:
continuous and saltatory conduction
Continuous conduction:
step by step depolarization and repolarization of each adjacent segment of the plasma membrane
Saltatory conduction:
special mode of action potential propagation that occurs along myelinated axons because of uneven distriution of voltage-gated channels
Electrical Synapses:
have gap junctions that have connexons which connect cytosol of two cells, which allows faster communication
Chemical synapses:
synaptic cleft w/neurotransmitters that chemically transmit messages from one neuron to another
Excitatory and Inhibitory postsynaptic potentials:
are types of action potentials that neurotransmitters will cause
Excitatory postsynaptic potential:
causes excitation of the effector (which is the structure that carries out the response)
Inhibitory postsynaptic potential:
Neurostansmitter moves post synaptic further away from threshold
A small molecule neurotransmitter that works at the neuromuscular junction; excitatory or inhibitory
Two excitatory Amino Acids:
glutamate and asparate; act in CNS
Two inhibitory Amino Acids:
Gamma aminobutyric acid and glycine; act in CNS
Biogenic amines:
modified and decarboxylated amino acids that excite or inhibit receptors
excitatory or inhibitory; role in regulating mood
excitatory or inhibitory; very active in emotional responses, including addictive behaviors
excitatory or inhibitory; involved in mood, sleep cycle, appetite , sensory perception
Protective structures of the spinal cord:
Vertebral column and meninges
Vertebral column:
provides bony protection
connective tissue of spinal cord
Dura mater:
outer layer of the meninges; dense irregular connective tissue
Arachnoid mater:
middle layer of the meninges; made of collagen and elastic fibers
Pia Matter:
inner most layer of meninges; made of bundles of collagen fibers and elastic fibers; helps supply blood to cord
Internal anatomy of the spinal cord:
Anterior median fissure, posterior median sulcus, Central canal, Gray matter, White matter
Anterior median fissure:
very deep groove of internal spinal cord
Posterior median sulcus:
very shallow groove of internal spinal cord
Central canal:
tunnels through center of spinal canal; filled with CSF
Anterior gray horns:
gray matter of spinal cord containing somatic motor nuclei
Posterior gray horns:
gray matter of spinal cord containing somatic (voluntary) and automatic (involuntary) sensory nuclei
Lateral gray horns:
gray matter of spinal cord present in thoracic area, upper lumbar and sacral parts of spine; autonomic motor nuclei
White matter:
tracts that extend entire length of spinal cord; bundles of axons faciliate more efficient communication;
Sensory tracts of white matter:
carry information toward the brain
Motor tracts of white matter:
carry information away from the brain
Three tracts of white matter:
Anterior, posterior and lateral white columns
Formation of spinal nerves:
the anterior and posterior roots unite to form the spinal nerves
Posterior root of spine:
contains only sensory axons
Anterior root of spine:
contains only motor axons
Connective tissue of spinal nerves:
Epineurium, Perineurium, Fascicles & Endoneurium
connective tissue wrapping of individual axons (neurons)
bundles of wrapped axons
connective tissue that wraps fascicle of spinal nerves
connective tissue wrapping of entire spinal nerve
branches of spinal nerves
Posterior ramus:
branch of spinal nerve that serves muscles in the skin of posterior trunk
Anterior Ramus:
branch of spinal nerve that serves anterior trunk and some structures of the limbs
Meningeal branch:
branch of spinal nerves that enters and exits vertebral cavity to supply vetebrae, ligaments, blood vessels of spinal cord
divisions of the anterior rami
Intercostal nerves:
Anterior rami of spinal nerves T2-T12
Lateral & Anterior spinothalamic tracts:
convey impulses for temperature sensation, pain, etc
perception of the position of a body part, independent of vision
Discriminative touch:
ability to feel what part of body is being touched
Two point discrimination:
ability to distinguish the touching of two points of body, even when close together
Integration centers:
where info is processed by interneurons, determines response and sends to motor neurons
Direct pathways:
send impulses for precise voluntary movements
Three Direct Pathways:
lateral corticospinal , anterior corticospinal tract, and cortiobulbar tract
Indirect pathways:
involved with coordination of body movements, skeletal muscle tone, posture & equilibrium
Three Indirect Pathways:
Rubrospinal, tectospinal and vestibulospinal tracts
fast automatic sequence of actions in response to a stimulus
Spinal reflex:
integration takes place in spinal cord; no brain process required
Cranial reflex:
integration takes place in lower portion of brain; tracking portion of reading
Somatic reflex:
involves contraction of skeletal muscles
Autonomic visceral reflex:
reflexes not consciously perceived; heart rate
sensory receptor sensitive to mechanical stimuli, stretching of blood vessels, stretching or bending of deformation of tissue
sensory receptor that responds to change in temperature
sensory receptor that responds to pain
sensory receptor that responds to light
sensory receptor that responds to chemicals
sensory receptors responds to changes in osmotic pressure
Sensory Neurons:
carries sensory information
Integration center:
where information is processed and decisions are made
Motor neurons:
carries response information to effectors
Part of body that carries out responses
Three protective coverings of brain:
dura mater, arachnoid mater and pia mater