Chapter 2: CELLS OF THE NERVOUS SYSTEM Flashcards
What are the main difficulties with studying brain cells?
- very small size (0.01-0.05mm)
- consistency
- uniform cream color
What is the widely used technique for the study of cells of the nervous system?
-Nissl staining: used to study the morphology and pathology of the nervous system, cytoarchitecture in the CNS.
Who are the two pioneers in this field?
- Camillo Golgi
- Santiago Ramon y Cajal
What does the neuron doctrine state?
That the nervous system is composed of nerve cells each of which is a structural unit in contact with other units but not in continuity.
What are the two basic divisions of the nervous system ?
- CNS (Central Nervous System): brain and spinal cord, communicates to the rest of the body through nerves.
- PNS (Peripheral Nervous System)
What is the definition of a neuron and and what are it’s four structures?
- Information-processing and information-transmitting element of the nervous system
- 4 structures: cell body (soma). dendrites, axon, terminal buttons
Three types of neurons and functions?
- Sensory, motor, inter.
1. Sensory gather information from the environment
2. Motor is responsible for movement and contraction of muscles.
3. Inter neurons connect motor and sensory.
Different types of structures of neurons
- Multipolar: A multipolar neuron is a type of neuron that possesses a single axon and many dendrites.
- Bipolar: a neuron with only two extensions—an axon and a dendrite—that run from opposite sides of the cell body.
- Unipolar: A unipolar neuron is a neuron in which only one process, called a neurite, extends from the cell body.
How is the soma of a neuron structured?
- Contains the nucleus
- Shape varies in different kinds of neurons
What is the function and structure of dendrites?
- treelike structure attached to the soma
- receives information transmitted across synapse
- Neurons “converse” with one another, and dendrites are recipients of these messages
What are the functions of dendritic spines?
- Increase the number of possible contact points between neurons
- Major substrate for brain plasticity
- In many mental illnesses or intellectual disabilities, dendritic spine pathologies were found.
How does communication proceed in the synapse?
- message sent from the terminal button, situated on the presynaptic cell.
- message received on the membrane of the postsynaptic cell.
What does the axon do?
- Carries information from the cell body to the terminal button
- The basic message it carries is called an action potential. It runs on the surface of the axon.(it is both electrical and chemical)
What system in the action potential allows messages to travel within the axon?
- axoplasmic transport: propels substances along the “tracks” that run inside the length of the axon.
- anterograde transport: from the soma to the terminal buttons
- retrograde transport: from the terminal buttons back to the soma.
What does the myelin sheath do?
surrounds axons and insulates them
What do the terminal buttons do?
- secrete a chemical called neurotransmitters
- forms the synapse with other neurons
Structure and function of the membrane?
- boundary of the neuron
- different kinds of proteins embedded in the membrane, which each serve different functions
Structure and function of cytoskeleton?
- matrix of strands of proteins
- gives the neuron its shape
- Thickest of the 3 kinds of protein strands: microtubules (structural support for the neuron, form the “tracks” for axoplasmic transport
Structure and function of the cytoplasm?
- fills the space surrounding the membrane, including the soma
- contains organelles: one of them is the mitochondria, which produces a chemical called adenosine triphosphate (ATP)
Structure and function of the nucleus?
- contains chromosomes which are long strands of DNA (deoxyribonucleic acid)
- chromosomes: contain recipes for making protein
- inside chromosome, gene: contains recipes for individual protein
Function of proteins?
-serve as enzymes: direct the chemical processes of a cell by controlling chemical reactions
What are the neurons surrounded of?
- a cellular membrane
- made of a self-organizing phospholipid bilayer
What are the different numbers of neurites a neuron can have?
- Anaxonic: no axon
- Unipolar: single neurite
- Bipolar: two neurite
- Multipolar: more than two neurites
What different morphology can neurons have?
- 2 shapes: stellate cells(star-shaped), and pyramidal cells (pyramid-shaped)
- spiny or aspinous.
