Chapter 2 Flashcards
(62 cards)
What are the two major classes of cells in the brain?
Neurons and the glia
What are neurons?
Neurons have a function to receive, integrate, and transmit information
- There are ~ 85 billion neurons in the human brain
- Each neuron receives on average more than 1,000 synaptic inputs
What are the glia?
The term glia means “glue”. They support neuronal functions. There are 3 major types of glia:
1. Oligodendrocytes and Schwann cells
2. Astrocytes
3. Microglia
What is the function of oligodendrocytes and Schwann cells?
Oligodendrocytes and Schwann cells wrap around the axon to provide insulation in the form of myelin
- Oligodendrocytes are found in the CNS and Schwann cells are found in the PNS
What is the function of the astrocytes?
Astrocytes provide supporting functions for neurons. They buffer potassium ions, take up glutamate released by neurons, and provide metabolic fuel
What is the function of microglia?
Microglia are the resident immune cells of the brain
- They become activated to help fight off infection and clear cellular debris via phagocytosis
- Involved in pruning/elimination synapses
What are the functions of neurons?
Neurons are excitable cells that:
- Process information
- Sense environmental changes
- Communicate changes to other neurons
- Command body response
What is histology?
Microscopic study of tissue structure
What is the function of a Nissl stain?
It stains cell bodies & facilitates the study of cytoarchitecture in the CNS
What is the function of a golgi stain?
It sparsely stains whole cells & allows imaging of a whole neuron (cell body and neurites)
What discoveries did the golgi stain lead to?
It revealed two parts of neurons: soma + perikaryon and neurites: axons and dendrites
- It also described the nervous system as continuous work (the Reticular theory)
What is Cajal’s contribution to the Golgi stain?
Cajal introduced the Neuron Doctrine
What is the Neuron Doctrine?
The Neuron Doctrine explains that the nervous system is made up of discrete individual cells
- Neurons communicate by contact, not continuity
- Neural circuitry
What is the simplified model of a neuron?
The pyramidal neuron
What are the parts of a neuron?
- Soma
- Nucleus
- Dendrites
- Axon Hillock
- Axon
- Myelin (optional)
- Node of Ranvier
- Axon Collateral
- Presynaptic Terminal
- Synaptic Vesicles
- Synaptic CLeft
- Postsynaptic Density
What are the components of the prototypical neuron?
The neuronal membrane and the cytoplasm
What does the neuronal membrane consist of?
- Phospholipid membrane barrier that encloses cytoplasm
- ~5 nm thick
- Portein concentration in membrane varies
- Structure of discrete membrane regions influences neuronal function
What does the cytoplasm consist of?
The cytoplasm consists of contents within a cell membrane (cytosol, organelles, NO nucleus)
What is cytosol?
Cytosol is watery fluid inside the cell
What are organelles?
Organelles are membrane enclosed structures within the soma
What functions occur in the nucleus?
Gene expression, transcription, and RNA processing
Why do neurons differ from other cells?
Neurons differ from other cells because of the expression of specific genes. We are able to understand these expression by the evolution of DNA and mRNA sequencing advances
What has genetic association studies helped us identify?
Genetic association studies have identified many genes involved in the development of diseases of the nervous system
What has single cell RNA-seq methodology?
Single cell RNA-seq methodology has allowed us to characterize mRNA expression differences across the different types of neuronal cell types
