Nervous tissue Flashcards
…………. is the focal point for the outgrowth of neuronal processes?
Nerve cell body
What is responsible for the amitotic nature of neurons?
Absence of centrioles
Axons arise from a cone-shaped area …………..
Axon hillock
Cytoskeleton of neuron is formed by ……………….
Microtubules and neurofilaments
The cell body is also known as …………
Soma
What are myelinated axons called in the CNS and PNS respectively?
Tracts in the CNS, and nerves in the PNS
Name two types of neuronal processes
Axons and dendrites
What are the two types of neuronal processes?
Axons and dendrites
……………. are the receptive or input regions of the neuron
Dendrites
Dendrites branch extensively from ………………
Dendritic tree
The glial cell that produces the lipid sheath of peripheral neurones is ……………
Swann cell
Cells of the nervous system that provide functional and structural support for the neurones are ………………
Glial cells
Golgi complexes are present in dendrites, true or false??
False
Axolemma refers to …………..
The plasma membrane of an axon
Axon terminals are also referred to as ………………….
Terminal boutons
Outline the two ways through which movement along an axon can occur
- Anterograde: toward the axon terminal
- Retrograde: toward the cell body
What are the functions of axons?
• Generate and transmit action potential
• Secrete neurotransmitters from the axonal terminals
……………. neurons conduct impulses towards the CNS
Sensory, or afferent
……………… carry impulses toward the body surface
Motor/efferent neurons
What are Interneurons
any neurons between a sensory and a motor neuron
What is a synapse?
A specialised region of contact between two neurons
Nerve impulse is transmitted from one neuron to the other through …………….
Neurotransmitters
3 varieties of synapses include …………..
Axodendritic
Axosomatic
Axoaxonic
Name the three parts of synapses
Presynaptic part
Synaptic cleft
Postsynaptic part
Myelin is produced by …………… in the CNS
Oligodendrocyte
Supporting cells of the CNS are grouped together as ………
Neuroglia
Name the types of neuroglia in the CNS
Astrocytes
Microglia
Ependymal cells
Oligodendrocytes
The type of astrocyte in the grey matter is …………
Protoplasmic
The white matter contains ………….. type of astrocytes
Fibrous
What are the functions of microglia
They are spider-like phagocytes that dispose of debris like dead brain cells and bacteria
A note on ependymal cells
They line the cavities of the brain and spinal cord, and circulate the CSF by beating their cilia.
They are arranged in a single layer, and could be ciliates cuboidal, or ciliated columnar in shape.
Oligodendrocytes can be defined as?
Small round cells with few cytoplasmic processes. Oligodendrocytes produce myelin sheath in the CNS.
What are the functions of myelin?
- Fatty insulation covering nerve cells
- They allow electrical signals transmit faster. They can be likened to wire coatings.
Define an axon
The axon of a neuronenveloped by special ectodermal sheaths.
A nerve is formed of a bundle of many nerve fibres, with their ectodermal sheaths.
Mention the CT sheaths surrounding nerve fibres
Endoneurium – Surrounds the axon of an individual neurone.
Perineurium – Surrounds a fascicle, which is a collection of neurones.
Epineurium – Surrounds the entire nerve, which is formed by a collection of fascicles. It contains numerous small blood vessels, which supply the nerve fibres. Epineurium appears on the nerve as it exits the intervertebral foramen.
Endoneurium is created by the fusion of ……………… layers of the meninges
Arachnoid and pia mater
What is the effect of multiple sclerosis?
It affects the ability of the nerve cells in the brain and spinal cord to communicate with each other.
Multiple sclerosis is caused by …………..
The attack of the body’s own immune system on myelin; this leads to the damage of myelin.
What is glioma?
Malignant tumour on the glial tissue of the nervous system.
What is Medulloblastoma?
It is a malignant tumour of the CNS, it is mostly found in the cerebellum of children.
What is schwannoma?
Schwannoma is a tumor that develops from Schwann cells in the PNS. They are usually benign.
…………… insulate and support cells of ganglia
Satellite cells
What’s the structural difference between the types of neuroglia?
They are both flattened cells, but satellite cells have prominent nucleus while Schwann cell have flattened nucleus.
