Structure of the central nervous system Flashcards
how many pairs of nerves do we have?
31 pairs of nerves
why do we have a lumbar system?
the spinal cord is shorter than the vertebral column. This means that at in the lumbar region we have fibre and cerebrospinal fluid
where do we carry out lumbar punctures?
between L3 and L4 in children and L4 and L5
this enusres there is not risk to the spinal cord
what makes up the grey matter in the spinal cord?
the cell bodies
what are the dorsal and ventral horns?
dorsal are the 2 top parts of the H where the sensory neurones come into the spinal cord
ventral are the 2 bottom parts of the H where the motor neurones leave the spinal cord
what is the white matter in the spinbal cord?
the myelinated axons
what are the functions of the spinal cord?
connects the PNS to the ANS
coordinates reflexes
carries sensory info to the brain
carries motor info to the muscles
describe the structure of the brain
- the brain stem made up of; midbrain pons medulla - the cerebrum: made up of diencephalon which is made up of the thalamus and the hyopthalamus the cerebellum the cerebral hemisphere- made up of cortex and basal ganglia
what is the brain stem responsible for?
control of breathing, heart rate, BP
control of defensive mechanisms e.g. coughing
What structure connects the right and left hemispheres?
Corpus Callosum
What lies beneath the corpus callosum?
Diencephalon
What is the role of the cerebellum?
Fine tuning motor function
What are the two parts of the diencephalon?
Thalamus - relay station for information going between the cerebral cortex and other areas of the CNS Hypothalamus - important in coordinating homeostasis (hypothalamo-hypophysial axis)
What is the role of the basal ganglia
Regulates voluntary movement
what makes up the corpus striatum?
putamen and caudate
diseases in striatum = huntingtons
cerebral cortex structure?
3-4 mm layer of grey matter with white matter underneath
structure of the cortex
6 layers of cells
what is the function of the hippocampus?
responsible for memory formation and is degenerated in alzheimers
what are commissural fibres?
they connect the 2 halves of the brain
they forms the corpus collusum
what are association fibres?
they connect parts of the same half together
what are projection fibres?
they join different parts of the brain together
the 3 layers of the meninges are?
dura mater
arachnoid mater
pia mater
Describe the ventricular system of the brain.
There are two large C shaped ventricles called lateral ventricles. There is one lateral ventricle for each cerebral hemisphere. The lateral ventricles narrow and form the 3rd ventricle, which is in the diencephalon The 3rd ventricle narrows to form the cerebral aqueduct, which passes down through the midbrain and becomes a tent-shaped structure called the 4th ventricle. The 4th ventricle is behind the pons and medulla and in front of the cerebellum. The 4th ventricle then narrows to form the central canal, which runs down the spinal cord.
What are the hole in the vertebral column that spinal nerves pass through called?
Intervertebral Foramina
What is the role of CSF?
CSF has a protective role - it is like the foetus being suspended inthe amniotic fluid. It also has a metabolic role in exchanging nutrients and removing waste.
Where does CSF leave the ventricles and enter the subarachnoid space?
CSF leaves the ventricles in the 4th ventricle, which has small holes in it
Where is cerebrospinal fluid produced?
By the choroid plexus, which is a special type of ependymal cell found in the ventricles.
differences between blood and CSF
fewer plasma proteins
lower glucose, calcium and potassium
higher chloride and magnesium
