Midterms: Organization of the Nervous System Flashcards
Arborizations which form connections or synapses with other neuron
Dendrites
What is the main job of an Axon?
conduct the impulse or the signal away from the cell body towards the other neuron /effector
Connections b/w one neuron to another or an effector
Anatomically just gaps
Functionally: area wherein signal is modified
Synapses
Types of Neurons
Unipolar
Bipolar (specialized or modified)
Pseudounipolar (specialized or modified)
Multipolar (common type)
For ascending or afferent
Pain, pressure, touch will be notice in the skin
Then going to the ?
For ascending or afferent
Pain, pressure, touch will be notice in the skin
Then going to the midbrain, medulla pons cerebellum
Emotions, sexual response, reaction to pain or pleasure, wakefulness
are all processed in the?
Subcortical level
T or F
Efferent neurons are for Sensory
Efferent neurons are for Motor function
*Somatic Nervous System
- Motor pathways going to the skeletal system
- Used for conscious movement
The lower brain or the sub cortical level is composed of?
(midbrain, pons, medulla, hypo, cerebellum, basal ganglia - they all modified the message)
Function of the Cortical Level or the higher brain
Fuctions with other parts of the NS
Memory, thought
Converts signals to determinative and precise function
It is not the highest center in the nervous system
What are the CNS SYNAPSES
Chemical synapses
Electrical synapses
Axodendritic?
Axosomatic ?
Axoaxomic ?
Axodendritic (maraming connections); Axon + Initial Segment of another axon
.
Axosomatic (mas onti); Axon + Dendrite
.
Axoaxomic (mas lalong onti); Axon + Nerve Cell Body
What are some alternative names for presynaptic terminals?
Terminal knobs, boutons, end-feet, or synaptic knobs.
What is the primary function of presynaptic terminals?
Conduction of action potential and release of neurotransmitters.
What triggers the release of neurotransmitters from presynaptic terminals?
Ca²⁺ influx via voltage-gated Ca²⁺ channels and activation of SNARE proteins.
What are the two general classes of SNARE proteins involved in synaptic transmission?
V-SNARE and T-SNARE.
Describe the location of presynaptic terminals in relation to the neuron.
Presynaptic terminals are found at the ends of nerve fibrils originating from many neurons and typically synapse onto dendrites and soma of the postsynaptic neuron.
What components are involved in the activation of post-synaptic receptors?
Binding component and ionophore component.
How do neurons in other parts of the spinal cord and brain differ from the anterior motor neuron?
They differ in cell body size, dendritic length, axon length, and the number of presynaptic terminals.
What is the role of ion channels in neurotransmission?
Ion channels control the passage of ions, such as potassium and calcium, which are crucial for synaptic transmission.
What physiological changes occur during excitation at the synapse?
Opening of Na and Ca channels, closure of Cl and K channels, and changes in cellular metabolism.
What is the function of the ionophore component in post-synaptic receptors?
It passes through the postsynaptic membrane to allow ion passage into the postsynaptic neuron.
What are ionotropic receptors and metabotropic receptors?
Ionotropic receptors directly gate ion channels, while metabotropic receptors act through second messenger systems.
Describe the physiological changes associated with inhibition at the synapse.
Opening of Cl and K channels, activation of inhibitory enzymes, and alterations in receptor expression favoring inhibition.
What is co-release of neurotransmitters?
Co-release refers to the simultaneous release of multiple neurotransmitters from a single presynaptic terminal.
Differentiate between co-transmission and co-transmission with spatial segregation.
Co-transmission involves the release of multiple neurotransmitters from a single terminal, whereas co-transmission with spatial segregation involves distinct neurotransmitters being released from different regions of the same terminal.
What does EPSP stand for, and what physiological changes does it involve?
EPSP stands for Excitatory Postsynaptic Potential. It involves the opening of Na or Ca channels, leading to depolarization or hypopolarization of the postsynaptic membrane.
Define IFSP and describe its physiological effects.
IFSP stands for Inhibitory Postsynaptic Potential. It involves the opening of Cl or K channels, resulting in hyperpolarization of the postsynaptic membrane.
What is orthograde transmission, and how does it contribute to nerve conduction?
Orthograde transmission refers to the transmission of nerve impulses in the direction of the axon terminal. It facilitates saltatory conduction, where nerve impulses jump from one node of Ranvier to another, speeding up conduction.
What is presynaptic inhibition, and how does it occur?
Presynaptic inhibition involves the opening of Cl channels by GABA at presynaptic terminals, reducing neurotransmitter release.
Explain temporal summation and spatial summation in synaptic transmission.
Temporal summation involves the cumulative effect of multiple stimuli arriving at the synapse in rapid succession, while spatial summation involves the combined effect of simultaneous stimuli from different synapses.
Describe the characteristics of facilitated neurons.
Facilitated neurons have a hypopolarized membrane, exhibit electronic conduction to the soma, have few Na channels, and undergo summation of inhibitory or excitatory signals.
What is the mechanism of action of strychnine on neuronal excitability?
Strychnine inhibits inhibitory neurons, increasing overall neuronal excitability by preventing the inhibition of excitatory signals.
Explain the effects of acidosis on neuronal activity.
Acidosis depresses neuronal activity by lowering the pH level of the blood, potentially leading to a comatose state.
What is the impact of hypoxia on neuronal function?
Hypoxia, or oxygen deprivation, can cause complete inexcitability of some neurons within seconds due to interrupted blood flow to the brain.
How does alkalosis affect neuronal excitability?
Alkalosis increases neuronal excitability by raising the pH level of the blood, potentially leading to conditions like epileptic seizures.
How do caffeine, theophylline, and theobromine affect neuronal excitability?
: They reduce the threshold for excitation of neurons, increasing their excitability.
What effect do anesthetics have on neuronal threshold and membrane properties?
Anesthetics increase the threshold for excitation and alter the properties of neuronal membranes.
Describe the steps involved in synaptic delay.
Synaptic delay includes the release of neurotransmitters, diffusion of neurotransmitters to the postsynaptic neuron, neurotransmitter-receptor interaction, changes in ion permeability, and the production of action potential.
