2: Cells of the Nervous system Flashcards
Lecture 2
What is the purpose of Glia?
Glia are supporting cells, it literally means Glue.
Where is Glia found?
Glia are dispersed in the grey matter but also contribute in the white matter.
Where is dendrites found?
Dendrites are mainly found in the dendritic cells and can also be found in other cells.
What is the purpose of dendritic cells?
They receive synaptic input and have a direct relationship with functionality and structural features such as spine.
What does it mean by “Dendritic spines are plastic”
It means that the spine changes significantly in shape, volume and number in small time courses.
What is the purpose of a single axon?
Transmit outputs
What is the structure of Axons
Axon is myelinated and is wrapped which derived from Glia cells. It is the myelin producing cells of the CNS.
Axons branch to form collaterals
Microtubules move materials from Soma to terminal
What does Soma mean?
The soma is also known as the cell body of the neurones which contains a nucleus and other structures common to living cells.
What does Retrograde transport mean?
Conveys materials from the axon to the cell body (Soma). Function of this process is recycling materials originally transported from cell body to axon.
What are the properties of Axon Terminals and Synapses?
- Axon end in terminal boutons
- It contains mitochondria and vesicles
- Simple neurotransmitters are made here
- Vesicles are discharged by exocytosis
- Post-synaptic receptors bind neurotransmitter
- Destruction or re-uptake of neurotransmitter then occurs
What is a terminal bouton
?Specialised presynaptic terminal at the end of an axon.
It contains necessary organelles, proteins and molecules needed to transmit chemical/electrical information to the post synaptic cell
How are neurotransmitters found?
They’re in a packet called vesicles within an axon
What is depolarisation?
The process of reversing the charge across a cell membrane.. Loss of the difference in charge between the inside and outside of the plasma membrane
What is polarisation
Membrane of cell is polarised (negative inside).
What is the process of Exocytosis?
Actin moves vesicles to the active zone
They attach to the presynaptic membrane and fuse with it
What is the purpose of Actin?
- Associated with movement and contraction, sits in the terminal.
What happens during the process of Endocytosis?
Retrieves the neurotransmitters back into their vesicles
What are the different types of Neurone?
- Projection Neurones
- Sensory Neurones
- Motor Neurones
- Interneurones
What is the structure of Projection Neurones and where they found?
- Found in primitive organisms
2. Have long axons and connect with sense organs, or muscles
What is the Property of Sensory Neurones
- Vertebrate sensory neurones have processes ending in skin, muscles and special sensory organs.
- They detect stimuli from the environment or inside the body
- They connect to other neurones to convey sensory information to the brain or spinal cord
What is the property of Motor Neurones?
- Axons of motor neurones may branch to form many terminals
- Their junctions are motto end plates
3 Efferent neurones - Involved with muscle contraction
What are efferent neurones
efferent neurons are motor neurons that carry neural impulses away from the central nervous systme and towards muscles to cause movement.
What are afferent neruones
Afferent neurons are sensory neurons that carry nerve impulses from sensory stimuli towards the central nervous system and brain
What are the unique features of Nerve cells?
- Small bodies but long axons
- Can NOT divide
- Found in hypo campus
- Sensitive, chemically and mechanically
- They are always in a constant need for glucose and oxygen due to the high energy usage
What are the different type of What is the purpose of Schwaan cells making myelin?
- Increases the species velocity (condition)
2. Guides axon growth and permits regeneration
What is the purpose of Oligodendrocytes?
- Makes myelin
- Increases conduction velocity
- Inhibit axon growth and regeneration
What happens at the border between PNS and CNS (e.g. a spinal cord)
- There is an astroglial border called the glia margin
- Axons traverse the border from PNS to CNS
- Schwaan cells end
- Oligodendrocytes begin
- Both can militate the same axon
What are Astrocytes?
- Specialised Glial cells that outnumber neurons by over five folds.
