Topic 5 - Nervous System Flashcards
A subdivision of the nervous system that consists of the brain and the spinal cord.
Central Nervous System (CNS)
A subdivision of the nervous system that consists of all nervous tissue outside of the brain and spinal cord.
Peripheral Nervous System (PNS)
Some different functions of the _______ system include:
- Sensory detection and input
- Integrative processing, storing and analyzing of sensory info for decision making
- Motor output
Nervous
_________ contain a lot of receptor sites for receiving chemical messages from other cells.
Dendrites
Fine processes in which the end of an axon divides into.
Axon Terminals
The swollen ends of some axon terminals.
Synaptic End Bulbs
A multilayered lipid and protein covering that speeds up signal conduction.
Myelin
Axons coated in myelin.
Myelinated Axons
The longest cells in the body that possess electrical excitability. They can respond to a stimulus and convert it to an action potential.
Neurons
Any change in the internal or external environment that is strong enough to stimulate an action potential.
Stimulus
An electrical signal that allows neurons to communicate with each other. They travel along the cell membrane of a neuron that allows them to communicate over small or large distances at different speeds.
Action Potential (AP)
What are the 3 structural classifications of neurons?
1) Multipolar
2) Bipolar
3) Unipolar
Neurons with several dendrites and one axon. Includes most neurons in the brain and spinal cord, as well as all motor neurons.
Multipolar
Neurons with one main dendrite and one axon. Generally these neurons are associated with sight and hearing.
Bipolar
Sensory neurons in the PNS with one point of attachment. The peripheral axon has sensory receptors and the central axon has axon terminals.
Unipolar
What are the 3 functional classifications of neurons?
1) Sensory Neurons
2) Motor Neurons
3) Interneurons
Neurons that are mostly classified as unipolar and contain either sensory receptors at the dendritic ends or are located just after sensory receptors that are separate cells. Once activated by a stimulus, the AP forms and propagates along the axon and is conveyed into the CNS. They travel together in the spinal and cranial nerves.
Sensory (aka. Afferent) Neurons
Neurons that are classified as multipolar and the AP propagates away from the CNS to effectors.
Motor (aka. Efferent) Neurons
The cells and organs that carry out an action (e.g. muscle fibres, glands).
Effectors
Neurons that are mostly classified as multipolar and are located primarily in the CNS between sensory and motor neurons. They integrate/process information from sensory neurons and if a motor response is required, the specifics of the response are formulated and relevant motor neurons are activated.
Interneurons (aka. Association Neurons)
The site of communication between two neurons or between a neuron and another type of cell.
Synapse
What are 2 types of synapses?
1) Electrical
2) Chemical
Synapses where APs conduct directly between the plasma membranes of adjacent cells through gap junctions. They produce fast communication and allow for synchronization of function (e.g. muscles of the heart).
Electrical Synapses
The more common type of synapse that allows your body to fine tune communication (slower) and can be found in skeletal muscle. When the AP reaches the end of the pre-synaptic neuron, it causes the release of a NT that diffuses across the synaptic cleft and binds to the post-synaptic neuron.
Chemical Synapses
The neuron sending the signal in a chemical synapse.
Pre-Synaptic Neuron
The neuron receiving the signal in a chemical synapse.
Post-Synaptic Neuron
The space between the communicating neurons in a chemical synapse.
Synaptic Cleft
A chemical protein released by the pre-synaptic neuron to affect (excite/inhibit) the post-synaptic neuron(s) or effector. Similar to a lock and key system.
Neurotransmitter (NT)
If the neurotransmitter is __________, continuation of the AP is more likely.
Excitatory
If the neurotransmitter is __________, continuation of the AP is less likely.
Inhibitory
A neurotransmitter found in the PNS/CNS that is excitatory at the neuromuscular junction.
Acetylcholine (ACh)
A neurotransmitter found in the CNS that is inhibitory.
Gamma-Aminobutyric Acid (GABA)
A neurotransmitter that can be excitatory or inhibitory, depending on the receptor. It generates emotional responses, addictive behaviours and skeletal muscle tone.
Dopamine
A neurotransmitter that can be excitatory or inhibitory, depending on the receptor. Related to sensory perception, temperature regulation, mood, sleep and appetite.
Serotonin
The 4 types of _________ in the CNS are:
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal Cells
Neuroglia
A type of neuroglia cell that helps form the blood-brain barrier and provide nutrients to neurons. They have a star-like appearance.
Astrocytes
A specialized barrier that prevents the passage of materials from the blood and the brain (and its surrounding fluid). It protects the brain from harmful substances, consists of tight junctions and has a thick basement membrane.
Blood-Brain Barrier (BBB)
A type of neuroglia cell that forms and maintains the myelin sheath of CNS neurons.
Oligodendrocytes
A type of neuroglia cell that are considered phagocytotic cells (similar to macrophages) that remove debris and phagocytize microbes.
Microglia
A type of neuroglia cell that lines the cavities of the brain and spinal cord that produce and assist in circulation of cerebrospinal fluid.
Ependymal Cells
A clear, colourless fluid that circulates around the brain and spinal cord that protects these structures from injury.
Cerebrospinal Fluid (CSF)
A type of neuroglia cell that encircles axons in the PNS and form the myelin sheath. They are also involved in the regeneration of PNS axons and are the only type of neuroglia in the PNS.
Schwann Cells
Some structures found in the __________ nervous system include:
- Cranial nerves & their branches
- Spinal nerves & their branches
- Ganglia
- Enteric plexuses
- Sensory receptors
Peripheral
A cluster of neuronal cell bodies in the CNS.
Nucleus
A cluster of neuronal cell bodies in the PNS.
Ganglion
A bundle of axons in the CNS that interconnect neurons in the spinal cord and brain.
Tract
A bundle of axons in the PNS.
Nerve
Nerves that connect the spinal cord to the periphery.
Spinal Nerves
Nerves that connect the brain to the periphery.
Cranial Nerves
Collections of cell bodies and unmyelinated nerve fibres in the CNS.
Grey Matter
Collections of myelinated axons in the CNS.
White Matter
A structure encased in the vertebrae that consists of white matter surrounding an inner core of grey matter. It extends from the bottom part of the brain stem to L2.
Spinal Cord
A structure that the spinal cord tapers into at L2.
Conus Medullaris
The roots of the spinal nerves below conus medullaris. The name of this structure translates to “horses tail.”
Cauda Equina
What are the 2 grooves that divide white matter into right and left sides?
1) Anterior Median Fissure
2) Posterior Median Sulcus
A small tube in the centre of the spinal cord that contains cerebrospinal fluid.
Central Canal
Each side of the grey matter surrounding the spinal cord is divided into regions called _____.
Horns
A horn containing axons of incoming sensory neurons and interneurons.
Posterior (aka. Dorsal) Horn
A horn containing motor nuclei.
Anterior (aka. Ventral) Horn
A horn containing sympathetic nuclei only present in the thoracic, upper lumbar and sacral portions of the spinal cord.
Lateral Horn
Each side of the white matter surrounding the spinal cord is divided into regions called _______. These contain tracts that have a common origin/destination.
Columns
A type of tract that consists of axons that conduct APs toward the brain.
Sensory (aka. Ascending) Tract
A type of tract that consists of axons that conduct APs away from the brain.
Motor (aka. Descending) Tract
The 4 structures/regions of the _____ are:
- Brain Stem
- Cerebellum
- Diencephalon
- Cerebrum
Brain
A region of the brain that is continuous with the spinal cord. It is the part between the spinal cord and the diencephalon. It contains nuclei of specific cranial nerves and net-like reticular formations extend throughout it.
Brain Stem
What are the 3 regions of the brain stem?
1) Medulla Oblongata
2) Pons
3) Midbrain
The most inferior region of the brain stem that contains centres (nuclei) for the control of heart rate, BP, breathing, swallowing and vomiting.
Medulla Oblongata
A region of the brain stem that contains centres for the control of breathing.
Pons
The most superior region of the brain stem that contains centres for reflex visual activities and hearing.
Midbrain
Nuclei found in the midbrain and neurons that make dopamine extend from it.
Substantia Nigra
A net-like formation of neural tissue that spreads throughout the brain stem.
Reticular Formation
A system found in the reticular formation of the brain stem that helps with consciousness, maintaining attention, preventing sensory overload by filtering out insignificant information and regulating muscle tone.
Reticular Activating System (RAS)
A region of the brain located posterior to the brain stem that smoothes and coordinates skeletal muscle contraction, as well as regulates posture and balance.
Cerebellum
What are the 3 components of the diencephalon?
1) Hypothalamus
2) Thalamus
3) Epithalamus
A part of the diencephalon that is a major regulator of homeostasis. Controls and integrates the ANS and is also involved in hormone production, emotion & behaviour (with the limbic system), eating, drinking and body temperature.
Hypothalamus
A 24 hour cycle in the biochemical, physiological, and/or behavioural processes of living things. It is regulated by the hypothalamus.
Circadian Rhythm
A part of the diencephalon that is the major relay station for most sensory input to the cerebral cortex.
Thalamus
A part of the diencephalon that contains the pineal gland, which is involved in smelling (especially emotional responses to smells).
Epithalamus
A region of the brain made up of 2 halves or hemispheres (right or left).
Cerebrum
What are the 3 structures of the cerebrum?
1) Cerebral Cortex
2) Association Areas
3) Basal Ganglia
An outer rim of grey matter that is part of the cerebrum and contains sensory areas involved in perception. It also contains motor areas involved in execution of voluntary movements.
Cerebral Cortex
An inner region of white matter part of the cerebrum that contain areas that deal with more complex functions (e.g. memory, emotions, reasoning, will, judgement, personality traits, intelligence).
Association Areas
Grey matter nuclei deep within the white matter that is part of the cerebrum. Helps to regulate the starting and stopping of movements, control subconscious contraction of skeletal muscles, suppress unwanted movement and set resting muscle tone.
Basal Ganglia (aka. Nuclei)
Basal ganglia are functionally linked to the __________ _____.
Substantia Nigra
A system involved in emotion, smelling and memory. It includes parts of the hypothalamus, the hippocampus, amygdala and other nearby structures.
Limbic System
A structure in the limbic system that functions in memory (e.g. encoding, consolidation, retrieval). It is very important in converting short term memory into long term memory.
Hippocampus
A structure in the limbic system that is important in emotional function, especially fear.
Amygdala
Three protective layers of connective tissue that encircle the brain and spinal cord, up to the point where the nerves exit the spinal cord.
Meninges
List the meninges from outermost to innermost.
1) Dura Mater
2) Arachnoid Membrane
3) Pia Mater
The adipose and connective tissue-filled space between the wall of the vertebral canal and the dura mater. There is none of this space in the brain.
Epidural Space
Interstitial fluid-filled space between the dura mater and arachnoid membrane.
Subdural Space
Cerebrospinal fluid-filled space between the arachnoid membrane and the pia mater.
Subarachnoid Space
Paths of communications between the brain and the periphery. Includes ___ pairs of nerves that exit from the base of the brain.
Cranial Nerves
12
Paths of communication between the spinal cord and the periphery. There are ___ pairs of nerves, which are parallel bundles of axons (and their associated neurological cells) wrapped in several layers of CT.
Spinal Nerves
31
How are the spinal nerves organized according to the region and level of the vertebral column from which they emerge?
C1-C8, T1-T12, L1-L5, S1-S5
The 1st pair of cervical nerves emerge from the spinal cord between the base of the skull and C1, also known as the _____.
Atlas
C1-C7 spinal nerves exit the spine _____ their corresponding vertebra.
Above
___ spinal nerve exits between C7 and T1 vertebrae.
C8
T1-L5 spinal nerves exit the spine _____ their corresponding vertebrae.
Below
Lumbar, sacral and coccygeal nerves descend from approximately ___ to their respective levels.
L2
Two bundles of axons that connect the spinal nerve to the spinal cord.
Nerve Root
A bundle of motor axons that only carry motor pathways.
Anterior (aka. Ventral) Root
A bundle of sensory axons that only carry sensory pathways.
Posterior (aka. Dorsal) Root
A swelling in the posterior root containing cell bodies of sensory (aka. unipolar, primary afferent) neurons of the PNS.
Posterior (aka. Dorsal) Root Ganglion
What are the 3 types of connective tissue in a spinal nerve?
1) Endoneurium
2) Perineurium
3) Epineurium
The innermost layer of connective tissue in a spinal nerve that covers the axon (whether it’s myelinated or not).
Endoneurium
The middle layer of connective tissue in a spinal nerve that covers fasciles (bundles of axons).
Perineurium
The outermost layer of connective tissue that covers the spinal nerve.
Epineurium
T/F - The perineurium and endoneurium are highly vascularized.
False - The perineurium and EPINEURIUM are highly vascularized.
What are the 3 subdivisions of the PNS?
1) Somatic Nervous System (SNS)
2) Autonomic Nervous System (ANS)
3) Enteric Nervous System (ENS)
Otherwise known as the voluntary nervous system, in which sensory neurons convey information to the CNS and then motor neurons conduct impulses from the CNS to skeletal muscles only.
Somatic Nervous System (SNS)
A system that monitors sensory and controls motor body activities automatically.
Autonomic Nervous System (ANS)
What are the 2 divisions within the ANS?
1) Sympathetic Nervous System (SyNS)
2) Parasympathetic Nervous System (PaNS)
Known as fight or flight where high sympathetic activity comes from being excited, scared or threatened. Responses include pupil dilation, increased HR/BP, airway dilation and glucose release. There may be vasodilation of skeletal and cardiac muscle or vasoconstriction of kidneys and the digestive tract.
Sympathetic Nervous System (SyNS)
Known as rest and digest where the goal is to conserve and restore energy substrates. Responses include increased digestive and urinary functions.
Parasympathetic Nervous System (PaNS)
The balance between sympathetic and parasympathetic activity that is regulated by the hypothalamus. Most organs have dual innervation, but a few solely receive sympathetic innervation (e.g. sweat glands, arrector pilli, kidneys, most BVs, adrenal medullae).
Autonomic Tone
T/F - The effects of sympathetic stimulation last longer and are more widespread than the effects of parasympathetic stimulation.
True
The major control and integration centre for the ANS is the hypothalamus.
Autonomic Control
A system in which sensory neurons monitor chemical changes within the GI tract and the stretching of its walls. Motor neurons control contraction of the GI tract smooth muscle and secretions of the GI organs.
Enteric Nervous System (ENS)
A peripheral sensory receptor detects stimulus and an AP travels along the axon to the cell body in the dorsal root ganglion. From there, the sensory axon may proceed in 3 ways.
Sensory Input
The axon extends into the white matter and travels up to the brain as part of a _______ tract.
Sensory
The axon enters the ______ horn and synapses with an interneuron, which in turn synapses with a somatic motor neuron in the _______ horn as part of a ______ ______ pathway.
Dorsal
Ventral
Spinal Reflex
The axon enters the dorsal horn and synapses with an ___________. Its axon crosses over into the _____ matter of the opposite side and travels up to the brain as part of a sensory tract.
Interneuron
White
What are the 2 ways motor output can occur?
1) Somatic
2) Autonomic
Axons from the motor tract synapse with the _______ motor neurons in the ventral horn on the _____________ side. These axons extend through the ventral root then the spinal nerve to innervate ________ _______.
Somatic
Contralateral
Skeletal Muscles
_________ motor neurons in the lateral horn send output along axons which sequentially pass through the lateral/anterior grey horns and the anterior root to enter spinal nerve. They will then synapse with another group of the same make up, which will innervate _______/______ muscles or ______.
Autonomic
Anterior
Cardiac/Smooth
Glands
Nervous tissue has a ____ metabolic rate and _______ is the primary energy substrate for the nervous system.
High
Glucose
T/F - Neurons have glycogen stores and don’t get it from the blood or neuroglial cells.
False - Neurons have NO glycogen stores and MUST get it from the blood or neuroglial cells.
T/F - Although nervous tissue can readily adapt, it has limited ability to regenerate.
True
In the __________ nervous system, damage to dendrites and myelinated axons can be repaired if the cell body is intact and Schwann cells are active.
Peripheral
In the _______ nervous system, little or no repair of damaged neurons occurs.
Central
