PHY2011 Lecture Notes - Lecture 21: Fourth Ventricle, Third Ventricle, Grey Matter
20 Jun 2018
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Week 8 T5L1 -the CNS, input, processing and output
Brain and spinal cord: core fluid-filled space, surrounded by grey matter, surrounded by
white matter
White matter: Myelinated cells
Grey matter: cell bodies and unmyelinated axons
Ventricles
oFour sets of fluid filled spaces in the brain
Paired C-shaped lateral ventricles
Third ventricle in diencephalon
Fourth ventricle in hind brain -extends to central canal of the spinal cord
Protecting the brain
oEntire brain covered in three tight membranes
Holds brain together
oFluid
Same as the fluid in the ventricles
Blood brain barrier formed by glial cells to stop movement of toxins
oBone
Skull/cranium
Outermost layer; protects brain
Spinal cord
oProtected by the vertebrae -wrapped around spinal cord
oTassels hanging off the sides of spine = spinal nerves
31 pairs of spinal nerves
Input/sensory neurons -bring in information to the CNS
Output/motor neurons
Sensory nerves coming in from the back of the spinal cord
Motor neurons coming out from the front
Motor neuron cell bodies in the grey matter
- Input from sensory neurons
- Input from the brain
find more resources at oneclass.com
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- Input from interneurons
Sensory neuron cell bodies just outside spinal cord
- Reflex reaction: sensory neuron has multiple endings
o Go to motor neuron to tell you to pull back
oGo to interneurons that go to other motor neurons that tell
you to move away
oGo to the brain and tell you you’re in pain
Interneurons in spinal cord
- Incoming sensory neuron
- Incoming motor neurons
Brain
oBrain stem (medulla, pons and midbrain) -oldest part of brain
Controls most vegetative functions
- Heart rate
- Blood pressure
- Respiration
- Movement of fluids
oCerebellum
Contains as many neurons as the rest of the brain
Fast balancing
oCerebrum (diencephalon and telencephalon)
Five lobes:
- Frontal
- Parietal
- Temporal
- Occipital
- Insula
Cortex – outer grey matter of the brain
- Six layers, of varying width, depending on role of that area of brain
- Internal integration layer
- Input layer
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Week 8 t5l1 -the cns, input, processing and output. Brain and spinal cord: core fluid-filled space, surrounded by grey matter, surrounded by white matter. Grey matter: cell bodies and unmyelinated axons. Ventricles: four sets of fluid filled spaces in the brain. Fourth ventricle in hind brain -extends to central canal of the spinal cord. Protecting the brain: entire brain covered in three tight membranes. Blood brain barrier formed by glial cells to stop movement of toxins. Spinal cord: protected by the vertebrae -wrapped around spinal cord, tassels hanging off the sides of spine = spinal nerves. Input/sensory neurons -bring in information to the cns. Sensory nerves coming in from the back of the spinal cord. Motor neurons coming out from the front. Motor neuron cell bodies in the grey matter. Sensory neuron cell bodies just outside spinal cord. Brain: brain stem (medulla, pons and midbrain) -oldest part of brain. Contains as many neurons as the rest of the brain.
