Lecture 1 - Intro to the nervous system Flashcards
Given that neuroscience is interdisciplinary, what others subjects must neuroscientists know?
- Biology
- Chemistry
- Physics (Neurons are electrically charged)
- Mathematics
How many neurons are in the human brain?
100 billion neurons
What is the size of a neuron?
10^-6 m (1 millionth of a meter)
What percent of the brain is used?
100%
What is the brain’s power in watts?
20 W (the whole body is 100 W)
What is the most common neurotransmitter?
Glutamate
What is the voltage of a neuron at rest?
-65 mV
What are the ions involved in neuro-electric activity?
Sodium (Na+), Potassium (K+), Chloride (Cl-), Calcium (Ca++)
How is the neuron like other cells?
- Enclosure (lipid bilayer membrane)
- Organelles (nucleus, mitochondria, etc.)
How is the neuron unlike other cells?
- Rapid excitation (action potential)
- Unique morphology (axons, dendrites)
What is the role of a dendrite?
It receives signals from other neurons (input)
What is the role of an axon?
It sends signals to other neurons (output)
What is one thing that all neurons must absolutely have?
An axon
What are three different morphologies that a neuron can have?
- Cortical pyramidal cell (longer cell body)
- Cortical stellate cell
- Cerebella Purkinje cell (dendrites form a square shape)
What is CNS and what consists it?
The Central Nervous System, and it is all parts of the nervous system within bone: thalamus, spinal cord, brain stem (midbrain, medulla, pons), cortex
What is PNS and what consists it?
The Peripheral Nervous System, and it is all parts of the nervous system not within bone: peripheral nerves
What are the four parts of the spinal cord and it what order from the brain?
- Cervical
- Thoracic
- Lumbar
- Sacral
What is the rule for the numbering of dermatomes?
The higher the number the more caudal, the lower the number the more rostral
Are there more Glial Cells or Neurons in the NS?
There are 3x more Glial Cells than Neurons in the nervous system
What are the three types of Glial Cells and what are there roles?
- Astrocyte: Maintain ionic movement
- Oligodendrocyte: Myelinate neurons
- Microglia: Scavenge cellular debris
What is the Nissl Stain and who invented it?
Franz Nissl invented the Nissl stain, and it consists of using dyes like thionine or cresyl violet to dye the endoplasmic reticulum, and be able to see the cell bodies and layers (some are neuropil).
However, the image he got was not detailed.
Who is Korbinian Brodmann and what did he do?
He used the Nissl stain to find different areas in the cerebral cortex. He found 52 cortical areas now known as Brodmann’s areas. He also noticed that the older the cortex, the fewer the layers (the neocortex is 6 layers).
AREAS 3, 2, 1: Primary somatosensory cortex
AREA 4: Primary motor cortex
AREA 17: Primary visual cortex
AREAS 41, 42: Primary auditory cortex
How do you prepare for a Nissl Stain?
- Tissue Fixation (Cross linking + Coagulation)
- Tissue Sectioning
Since the lipid bilayer membrane is impermeable to ions what are the two ways that ions can get through?
Ion transports (ion movement against concentration gradient)
Ion channels (ion movement with the concentration gradient)