78 Questions
What are the functions of nervous tissue as mentioned in the text?
Receive and transmit stimuli, integrate and associate information
What are the specific properties of nervous tissue mentioned in the text?
Irritability and conductivity
What is the ectodermal origin of nervous tissue mentioned in the text?
Neuroectoderm or neuroepithelium
What is the main composition of nervous tissue as mentioned in the text?
Neurons and neuroglial cells
Which part of the chemical synapse contains neurotransmitters within vesicles?
Presynaptic part
What is the space between the pre- and post- synaptic membranes called?
Synaptic cleft
Which ion channels are opened at excitatory synapses?
Sodium and potassium
What triggers the fusion of the synaptic vesicles with the presynaptic membrane?
Elevation of cytoplasmic calcium
Which part of the neuron transmits the nerve impulse and contains the synaptic button?
Axon
What is the active site of the synapse, where the synaptic vesicles empty their contents by exocytosis?
Focal thickenings of the protein layer
What is the space between the pre- and post- synaptic membranes occupied by?
Glycosaminoglycans
Which part of the neuron contains receptors for neurotransmitters?
Postsynaptic part
What type of neurotransmitters are directly related to ion channels?
Neurotransmitters
What type of neurotransmitters activate a second messenger and are related to G proteins or receptor kinases?
Neuromodulators and Neurohormones
What triggers the activation of the synapse?
Arrival of an action potential
What stops synaptic activity?
Enzymes degrade neurotransmitter molecules
What is the function of sensory neurons?
Receive input and conduct impulses to the CNS
What is the role of interneurons?
Establish networks between sensory and motoneurons
What is the composition of a nerve fiber?
Cell sheath and myelin sheath
What forms the cell sheath in the CNS?
Oligodendrocytes
What is the function of myelin?
Electrical isolation and increases the speed of conduction
Where are electrical synapses found?
In the nervous system
What is the site where nerve impulses are transmitted between cells called?
Synapse
What is the function of chemical synapses?
Involvement of neurotransmitters in transmitting nerve impulses
What forms the myelin sheath in the PNS?
Schwann cells
What is the role of motoneurons?
Conduct impulses to muscles, glands, and other neurons
What is the function of unmyelinated nerve fibers?
Conduct impulses with only a cell sheath, formed by Schwann cells
What is the composition of myelinated nerve fibers?
Cell sheath and myelin sheath
Neurons outnumber neuroglial cells in the nervous tissue of vertebrates.
False
The nervous tissue has an endodermal origin.
False
The specific properties of nervous tissue are irritability and conductivity.
True
Oligodendrocytes form the myelin sheath in the CNS, while Schwann cells form it in the PNS.
False
Myelin is responsible for decreasing the speed of conduction in nerve fibers.
False
Interneurons conduct impulses to muscles, glands, and other neurons.
False
Neurons are composed of the soma, dendrites, and axon.
True
The soma is responsible for producing structural proteins, membrane proteins, and enzymes.
True
Axonal transport can only be anterograde, and does not involve retrograde movement.
False
Chemical synapses can only be interneuronal and never neuroeffector.
False
The synaptic cleft is between 12 and 30 nm wide.
True
Neurotransmitters activate a second messenger and are related to G proteins or receptor kinases.
True
The presynaptic part contains neurotransmitters within vesicles, which are released into the space between the two cells called the synaptic cleft.
True
At inhibitory synapses, the permeability for potassium and chloride ions increases, leading to depolarization of the postsynaptic membrane.
False
Synaptic activity stops when enzymes degrade neurotransmitter molecules in the membrane of the postsynaptic element.
True
Neuroglial cells outnumber neurons in the nervous tissue of vertebrates.
True
The nervous tissue has an endodermal origin.
False
The specific properties of nervous tissue are irritability and conductivity.
True
Neurosecretory neurons release neurotransmitters at synapses
False
Axonal transport can only be anterograde, and does not involve retrograde movement
False
The soma is responsible for transmitting nerve impulses
False
Oligodendrocytes form the myelin sheath in the PNS, while Schwann cells form it in the CNS.
False
Synaptic activity stops when enzymes degrade neurotransmitter molecules in the membrane of the postsynaptic element.
False
At inhibitory synapses, the permeability for potassium and chloride ions increases, leading to depolarization of the postsynaptic membrane.
False
Chemical synapses are always excitatory in nature.
False
The presynaptic part contains neurotransmitters within vesicles, which are released into the space between the two cells called the synaptic cleft.
True
The postsynaptic part contains receptors for neurotransmitters.
True
The synaptic cleft is the space between the pre- and post- synaptic membranes.
True
Synaptic activity stops when degradation products of neurotransmitter molecules are collected by the presynaptic element for synthesis of the new neurotransmitters.
False
The space between the pre- and post- synaptic membranes is occupied by glycosaminoglycans that are PAS-positive.
True
Neurons outnumber ______ cells in the nervous tissue of vertebrates.
neuroglial
The specific properties of nervous tissue are irritability and ______.
conductivity
The nervous tissue has an ectodermal origin, specifically the neuroectoderm or ______.
neuroepithelium
The specific properties of nervous tissue are ______ and conductivity.
irritability
There are about 50 times more ______ cells than neurons in the nervous tissue of vertebrates.
neuroglial
Neurons outnumber ______ cells in the nervous tissue of vertebrates
neuroglial
The space between the pre- and post- synaptic membranes is occupied by ______ that are PAS-positive
glycosaminoglycans
Neurotransmitters activate a second messenger and are related to G proteins or ______ kinases
receptor
The specific properties of nervous tissue are irritability and ______
conductivity
Oligodendrocytes form the cell sheath in the CNS, while Schwann cells form it in the ______
PNS
Neurons are classified based on their ______, with conduction neurons being the majority and having different distributions like unipolar, bipolar, pseudounipolar, and multipolar
function
The soma is responsible for producing structural proteins, membrane proteins, and enzymes, and contains Nissl bodies, SER, Golgi complex, mitochondria, and cytoskeletal ______
filaments
Dendrites increase the neuron's surface area and receive ______, while the axon contains axolemma, axoplasm, SER, mitochondria, vesicles with neurotransmitters, neurosecretory granules, lysosomes, and an ordered cytoskeleton
synapses
Axonal transport can be anterograde or ______, facilitating the spread of organoids, vesicles, macromolecules, and proteins
retrograde
Neurosecretory neurons are specialized in secreting substances and transporting them along the axon for release into the ______
blood
Chemical synapses have three parts: (1) the presynaptic part (2) the central part or synaptic cleft, and (3) the ______ part
postsynaptic
Neurotransmitters bind to receptors on the ______ cell membrane, receptors that open ion channels
postsynaptic
In the cytoplasm of the synaptic button, there are mitochondria, a few elements of the smooth endoplasmic reticulum, actin microfilaments, and many ______ located next to the plasma membrane
vesicles
The space between the pre- and post-synaptic membranes is called the ______
synaptic cleft
At excitatory synapses, there is a simultaneous increase in permeability for sodium and potassium ions and this leads to ______ of the postsynaptic membrane
depolarization
Study Notes
Neurons and Nerve Fibers
- Neurons can be sensory (afferent), interneurons, or motoneurons (efferent)
- Sensory neurons receive input and conduct impulses to the CNS
- Interneurons establish networks between sensory and motoneurons
- Motoneurons conduct impulses to muscles, glands, and other neurons
- Nerve fiber consists of the axon and its sheaths
- Myelinated nerve fibers have cell sheath and myelin sheath
- Oligodendrocytes form the cell sheath in the CNS, while Schwann cells form it in the PNS
- Unmyelinated nerve fibers only have a cell sheath, formed by Schwann cells
- Myelin is a lipoprotein substance formed by oligodendrocytes in the CNS and Schwann cells in the PNS
- Myelin is responsible for electrical isolation and increases the speed of conduction
- Synapse is the site where nerve impulses are transmitted between cells
- There are electrical and chemical synapses, with neurotransmitters involved in chemical synapses
Neuron Components and Function: A Detailed Overview
- Nervous tissue comprises nervous cells (neurons and neuroglial cells) and neuropil.
- The neuron consists of the soma (neuronal body) and neuronal processes (dendrites and axon).
- The soma is polygonal and ranges in size from 4 to 135 µm, with a prominent nucleolus, dispersed chromatin, and various organelles for protein synthesis and secretion.
- The soma contains Nissl bodies (chromatophilic substance), SER, Golgi complex, mitochondria, cytoskeletal filaments, and inclusions like lipofuscin, melanin, and secretion granules.
- Dendrites increase the neuron's surface area and receive synapses, while the axon is a single, long, thin, and smooth prolongation with different segments.
- The axon contains axolemma, axoplasm, SER, mitochondria, vesicles with neurotransmitters, neurosecretory granules, lysosomes, and an ordered cytoskeleton.
- Axonal transport can be anterograde or retrograde, facilitating the spread of organoids, vesicles, macromolecules, and proteins.
- Neurons are classified based on their function, with conduction neurons being the majority and having different distributions like unipolar, bipolar, pseudounipolar, and multipolar.
- Neurosecretory neurons are specialized in secreting substances and transporting them along the axon for release into the blood.
- Conduction neurons release neurotransmitters at synapses, while neurosecretory neurons release substances into the blood in neurohemal organs.
- Soma is responsible for producing structural proteins, membrane proteins, and enzymes, and contains Nissl bodies, SER, Golgi complex, mitochondria, and cytoskeletal filaments.
- Dendrites increase the neuron's surface area and receive synapses, while axon contains axolemma, axoplasm, SER, mitochondria, vesicles with neurotransmitters, neurosecretory granules, lysosomes, and an ordered cytoskeleton.
Neurons and Nerve Fibers
- Neurons can be sensory (afferent), interneurons, or motoneurons (efferent)
- Sensory neurons receive input and conduct impulses to the CNS
- Interneurons establish networks between sensory and motoneurons
- Motoneurons conduct impulses to muscles, glands, and other neurons
- Nerve fiber consists of the axon and its sheaths
- Myelinated nerve fibers have cell sheath and myelin sheath
- Oligodendrocytes form the cell sheath in the CNS, while Schwann cells form it in the PNS
- Unmyelinated nerve fibers only have a cell sheath, formed by Schwann cells
- Myelin is a lipoprotein substance formed by oligodendrocytes in the CNS and Schwann cells in the PNS
- Myelin is responsible for electrical isolation and increases the speed of conduction
- Synapse is the site where nerve impulses are transmitted between cells
- There are electrical and chemical synapses, with neurotransmitters involved in chemical synapses
Neuron Components and Function: A Detailed Overview
- Nervous tissue comprises nervous cells (neurons and neuroglial cells) and neuropil.
- The neuron consists of the soma (neuronal body) and neuronal processes (dendrites and axon).
- The soma is polygonal and ranges in size from 4 to 135 µm, with a prominent nucleolus, dispersed chromatin, and various organelles for protein synthesis and secretion.
- The soma contains Nissl bodies (chromatophilic substance), SER, Golgi complex, mitochondria, cytoskeletal filaments, and inclusions like lipofuscin, melanin, and secretion granules.
- Dendrites increase the neuron's surface area and receive synapses, while the axon is a single, long, thin, and smooth prolongation with different segments.
- The axon contains axolemma, axoplasm, SER, mitochondria, vesicles with neurotransmitters, neurosecretory granules, lysosomes, and an ordered cytoskeleton.
- Axonal transport can be anterograde or retrograde, facilitating the spread of organoids, vesicles, macromolecules, and proteins.
- Neurons are classified based on their function, with conduction neurons being the majority and having different distributions like unipolar, bipolar, pseudounipolar, and multipolar.
- Neurosecretory neurons are specialized in secreting substances and transporting them along the axon for release into the blood.
- Conduction neurons release neurotransmitters at synapses, while neurosecretory neurons release substances into the blood in neurohemal organs.
- Soma is responsible for producing structural proteins, membrane proteins, and enzymes, and contains Nissl bodies, SER, Golgi complex, mitochondria, and cytoskeletal filaments.
- Dendrites increase the neuron's surface area and receive synapses, while axon contains axolemma, axoplasm, SER, mitochondria, vesicles with neurotransmitters, neurosecretory granules, lysosomes, and an ordered cytoskeleton.
Test your knowledge of neurons, nerve fibers, and neuron components with this quiz. Explore the functions of different types of neurons, nerve fiber structures, myelination, synapses, and more.
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