CNS I Flashcards
(47 cards)
How much does an adult human brain typically weigh?
1400g
Approximately how many neurones does a brain contain?
~10^12 neurons
How many synaptic contacts does each neurone receive?
200,000 synaptic contacts
What are 2 other facts
-The brain is a predicting machine, responds to it’s environment based
on what it’s learned in the past
- Specific areas are responsible for certain tasks
What kind of networks do simple organisms have and and, the benefit of it? (What is the evolution of the nervous system?)
-Simple organisms (e.g. jellyfish)
- neural networks
- allow them to sense their environment but have no central integrating centre or brain
What kind of neurones do higher organisms have?
(What is the evolution of the nervous system for higher organisms?)
-Higher organisms (e.g. Snails, flatworms)
-possess collection of neurones in the head - cephalic ganglion - a
rudimentary brain
-In higher animals the cephalic ganglia become segmented
into regions, each with a defined function
What does the cerebrum show?
-Shows the most dramatic change during development.
-In man it is the most distinctive part of the brain
What are central pattern generators, and what are they responsible for in humans ?
- Circuits that give rise to rhythmic motor activity
- Once activated, they create spontaneous, repetitive movement
- In humans this is responsible for locomotion and breathing, among other
things
How are tissues referred to in the brain ?
- The colour it appears
What are the 3 facts of the gray matter?
-Neuronal cell bodies
-Often clearly organised in layers within certain brain regions
-In other areas of the brain they are grouped together into nuclei and identified by
specific names
What are 2 facts of the white matter ?
- Mostly axons
- Appear white due to myelination (fatty tissue)
What does ‘rostral’ mean ?
- towards the front
What does ‘caudal’ mean ?
- towards the tail
What does ‘dorsal’ mean ?
- towards the back
What does ‘ventral’ mean ?
towards the stomach
What does ‘sagittal’ mean ?
- parallel to the midline
What does ‘coronal’ mean ?
- divides NS into anterior and posterior parts
What does horizontal (transverse) mean ?
- divides NS into dorsal and ventral parts
What is the ‘nucleus’ ?
- collection of nerve cells visible under the microscope as a distinct structure
What are neurones ?
- excitable cells of the brain
What are the type of glia cells ?
- Astrocytes
- Microglia
- Ependymal cells
- Oligodendrocytes: myelin sheath
What are ‘Astrocytes’ ?
- Glia cells that is responsible for mechanical support, growth factors, some forms of plasticity
What is ‘Microglia’ ?
- c.f. macrophages
What are ‘Ependymal cells’ ?
- lining of the ventricles