Organisation of the Central Nervous System Flashcards
What structure connects the two hemispheres of the brain?
Corpus Callosum
- bendy bit of white matter
- constant conversation between two hemispheres
What area is under the corpus callosum
Diencephalon
- consists of thalamus and hypothalamus
Functions of the Cerebellum
Motor Function
- not initiation but coordination
- important for learning motor skills e.g. playing the piano
Functions of the Brain Stem?
- Contains nuclei which controls vital functions:
- respiratory centre + cardiac centre
- ascending/descending pathways go through the brain stem
- Cranial nerves attached to the brain stem providing sensory + motor innervation
Functions of the Diencephalon?
Thalamus - higher areas of diencephalon - relay station between cerebral cortex + other parts of CNS
Hypothalamus - inferior to the thalamus, important in coordinating homeostasis
Functions of the Cerebral Cortex
- Many nuclei
- one of them is the basal ganglion
- Basal Ganglia = group of nuclei which produce movement pattern and work with the motor cortex
Describe development of the brain?
First develops into 3 parts:
- forebrain
- midbrain
- hindbrain
Forebrain - divides into: cerebral hemispheres + diencephalon
Midbrain - stays same
Hindbrain - pons, medulla, cerebellum
Describe the Cortex ?
Left side of the Left Hemisphere. 2 Types:
- Primary Cortical Areas
- Association Cortex
Describe the Primary Motor Cortex?
- axons travel down thedescendingpathway to stimulate motor neurons in the spinal cord
- somatotopic arrangement - upside down body
- contralateral arrangement
Describe Primary Somatosensory Cortex?
- adjacent to primary motor cortex
- receives general sensory information coming from body
Describe Primary Auditory Cortex?
- first to receive information from ears
Describe Primary Visual Cortex?
first to receive info from the retina
What is the Association Cortex?
Much higher functions take place
- learning, thinking, percep
What is Wernicke’s Area?
Important for understanding language
What is Broca’s Area?
Important for speech
Describe the Ventricular System?
Lateral Ventricles
- 2 large C shaped ventricles with a spur at back
- lateral ventricles in each hemisphere
3rd Ventricle
- single midline ventricle
- middle of the diencephalon
Cerebral Aqueduct
- base of third ventricle narrows to form a fine channel
4th Ventricle
- tent shaped
- pons and medulla is in front
-
Central Canal
- lower part of the medulla the 4th ventricle which narrows and goes down into the spinal cord
What is Cerebrospinal Fluid?
- Produced by the Choroid Plexus (ependymal cell) found in the ventricles
- Filters the blood - removes cells and then secretes
- circulates through ventricular system –> 4th Ventricle
- 4th ventricle has holes so CSF can exit
- circulates in the sub-arachnoid space between the meninges
- reabsorbed into the venous system by Arachnoid Villi
Describe the Layers of the Meninges?
- Dura, Arachnoid, Pia Mater
- between arachnoid and the pia have the sub-arachnoid space where CSF can circulate
- venous sinuses over the surface of the brain
- out-pockets of the arachnoid membrane push through the walls of the venous sinuses for CSF reabsorption - ARACHNOID VILLI
- blockage –> CSF buildup = hydrocephalus
