The nervous system Flashcards
what is the central Nervous system
the brain and the spinal cord
What is the peripheral Nervous system
everything else in the nervous system other than the brain and spinal chord
What is a glial cell ?
one of a variety of cells that provide a framework of tissue that supports the neurons and their activities.
Whats a neuron ?
Neurons are cells and
therefore have a soma, or cell body, but they also have extensions of the cell; each extension is generally referred to as a
process. There is one important process that every neuron has called an axon, which is the fiber that connects a neuron with
its target. Another type of process that branches off from the soma is the dendrite.
what is a localised collection of neuron cell bodies in the CNS called ?
A localized collection of neuron cell bodies in the CNS is referred to as a nucleus
What is a ganglion
In the PNS, a cluster of neuron cell bodies
is referred to as a ganglion.
What is a tract ?
A bundle of axons, or fibers, found in the CNS
is called a tract
What is a nerve ?
A bundle of axons, or fibers, found in the PNS
what is gray matter
Group of Neuron Cell Bodies (neuron/ganglion)
what is white matter
Bundle of Axons (tract/Nerve)
what is a neuropeptide
a neurotransmitter molecule made up of chains of amino acids connected by peptide bonds. This is
what a protein is, but the term protein implies a certain length to the molecule.
is glutamate exhibitory or excitatory
Glutamate is considered an excitatory amino acid, but only because Glu receptors in the adult cause depolarization of
the postsynaptic cell.
is glycine exhibitory or excitatory
Glycine is considered inhibitory amino acids, again because their receptors cause
hyperpolarization.
is GABA excitatory or inhibitory
GABA is considered inhibitory amino acids, again because their receptors cause
hyperpolarization.
what are ionotrophic receptors ?
Ionotropic receptors are ligand-gated ion channels, such as the nicotinic receptor for
acetylcholine or the glycine receptor.
what is an effector protein ?
An effector
protein is an enzyme that catalyzes the generation of a new molecule, which acts as the intracellular mediator of the signal
that binds to the receptor. This intracellular mediator is called the second messenger.
what is a metabotrophic receptor ?
A metabotropic receptor is a complex that causes metabolic changes in the cell when the neurotransmitter
binds to it (1). After binding, the G protein hydrolyzes GTP and moves to the effector protein (2). When the G protein
contacts the effector protein, a second messenger is generated, such as cAMP (3). The second messenger can then
go on to cause changes in the neuron, such as opening or closing ion channels, metabolic changes, and changes in
gene transcription.
what is the absolute refractory period ?
time during an action period when another action potential cannot be generated because
the voltage-gated Na+
channel is inactivated
What is the function of an astrocyte
glial cell type of the CNS that provides support for neurons and maintains the blood-brain barrier
regulate ion concentration in the intercellular space
uptake/breakdown of neurotransmitters
formation of the blood brain barrier (the membrane separating the circulatory system from the brain)
What is the autonomic nervous system
functional division of the nervous system that is responsible for homeostatic
reflexes that coordinate control of cardiac and smooth muscle, as well as glandular tissue
what are proprioreceptors
are mechanoreceptors that detect the position or movement of a part of the body and help regulate movement
What is a muscle spindle
is a kind of proprioceptor parallel to the muscle that responds to a stretch, and can cause contraction of the muscle
what are the two afferent pathways to the brain
Dorsal column lemniscal for fine touch, vibration and position
Spinothalamic tract for crude touch temperature, and pain
what is the function of the primary somatosensory cortex
Function (simple): receives sensory input from the body
Function: receives the bulk of the thalamocortical projections from the sensory input fields
what is the function of the primary motor cortex
Function (simple): is one of the principal brain areas involved in motor function
Function: works in association with other motor areas to plan and execute movements
- Direct contraction of specific muscles
- Direct a combination of contractions to produce a specified outcome
what does the prefrontal cortex do ?
response to lights, noises and other sensory signals
calculates predictable outcomes of actions and plans movement accordingly
where is the prefrontal cortex ?
the front of the brain
what does the premotor cortex do ?
- is active during preparation for movement and receives information about a target in space
- integrates information about position and posture of the body and organizes the direction of the movement in space
what is the supplementary motor cortex useful for ?
Is important for organizing a rapid sequence of movements
what is the supplemental parietal cortex useful for ?
contributes visual information (hand eye coordination!)
What is one of the functions of the cerebellum ?
The cerebellum is a structure in the brain often associated with balance and coordination
Known as ‘the little brain’ it has more neurons than the rest of the brain (and has a cortex)!
Supplements and coordinates other motor areas to give a smooth output
What would damage to the cerebellum cause ?
Damage to the cerebellum causes trouble with rapid movement requiring aiming and timing.
Examples: clapping hands, speaking, writing, etc.
Damage also leads to postural impairments, tremor, lack of coordinated movements (ataxia)
How many parts does the basal ganglia have ?
3
Putamen
Caudate nucleus
Globus pallidus
What actions does the basal ganglia help with
Basal ganglia is critical for learning motor skills, organizing sequences of movement, and learning “automatic” behaviors
Starting and finishing movements are influenced by the basal ganglia
what does viscera mean ?
internal
What does the viscera monitor ?
Monitor temperature, pain, irritation, chemical changes and stretch in the visceral organs
Brain interprets as hunger, fullness, pain, nausea, well-being
what is the simplified pathway from the viscera ?
Simplified pathway: sensory neurons to spinothalamic tract (see lesson 4 notes) to thalamus to cerebral cortex
what is the role of the amygdala
- Stimulates sympathetic activity, especially previously learned fear-related behavior
- Can be voluntary when recalling frightful experience - cerebral cortex acts through amygdala
- Some people can regulate some autonomic activities by gaining extraordinary control over their emotions
what is an example of why is hard to localise referred pain from the heart
Nociceptive afferents from viscera synapse on the same polymodal neurons in the main sensory nucleus of the dorsal horn as do some of the Aβ fibres from skin mechanoceptors.
