18 Questions
Which organelle completely surrounds the nucleus of a neuron and appears as a dark brown network?
Golgi body
What is the main function of the rough endoplasmic reticulum in a neuron?
Protein synthesis
Which part of the neuron is highly metabolically active and contains organelles and inclusions?
Cytoplasm
What structures supply the high energy requirements of a neuron, especially near the axon terminals?
Mitochondria
What happens to Nissl's granules (rough endoplasmic reticulum) in a neuron upon injury?
They disappear (chromatolysis)
Which part of the neuron has a large, central, and rounded structure, with a thick nuclear membrane and a prominent nucleolus?
Nucleus
What is the function of neurotubules in neurons?
Transport substances down the axon
Where is melanin pigment primarily present in the nervous system?
In the spinal and sympathetic ganglia
What is the primary function of lysosomes in neurons?
Break down cell components
Where are lipofuscin pigment levels known to increase?
With old age
Which type of nerve cells have only one process and no dendrites?
Unipolar nerve cells
What is the purpose of lipid droplets and glycogen in neurons?
Energy storage
Where are bipolar nerve cells found?
Spiral ganglion, retina, olfactory mucosa
What is a characteristic feature of pyramidal nerve cells?
Resemble a pyramid with a long apical dendrite
Which type of neuron has short axons, like those found in the retina and cerebral cortex?
Pyriform neurons
Where are sensory neurons present?
Neurons of spinal ganglia
Which type of neurons connect sensory and motor neurons in the reflex arc of the spinal cord?
Interneurons
In which part of the body are stellate neurons typically found?
Sympathetic ganglia
Study Notes
Neuron Structure
- The organelle that completely surrounds the nucleus of a neuron and appears as a dark brown network is the Nissl's granules or rough endoplasmic reticulum.
- The main function of the rough endoplasmic reticulum in a neuron is to synthesize proteins.
- The perikaryon, also known as the cell body, is highly metabolically active and contains organelles and inclusions.
- Mitochondria supply the high energy requirements of a neuron, especially near the axon terminals.
Nissl's Granules and Injury
- Upon injury, Nissl's granules (rough endoplasmic reticulum) in a neuron undergo chromatolysis, which is the dissolution of Nissl's granules.
Neuron Characteristics
- The nucleus of a neuron has a large, central, and rounded structure, with a thick nuclear membrane and a prominent nucleolus.
- Neurotubules provide structural support, shape, and transport of materials within neurons.
- Melanin pigment is primarily present in the nervous system, specifically in the substantia nigra and locus ceruleus.
Lysosomes and Pigments
- The primary function of lysosomes in neurons is to break down and recycle cellular waste and debris.
- Lipofuscin pigment levels are known to increase with age, especially in the heart and nerve cells.
Types of Neurons
- Unipolar neurons have only one process and no dendrites.
- Lipid droplets and glycogen in neurons serve as energy storage.
- Bipolar nerve cells are found in the retina and inner ear.
- Pyramidal nerve cells have a characteristic pyramidal shape with a triangular cell body.
- Stellate neurons are star-shaped and typically found in the cerebral cortex.
- Interneurons connect sensory and motor neurons in the reflex arc of the spinal cord.
- Sensory neurons are present in the sensory organs, such as the eyes, ears, and skin.
Learn about the structural and functional characteristics of neurons, the basic unit of the nervous system. Explore the components of a nerve cell body and the functions of dendrites and axons.
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