Name the four lobes of the brain and the function of it
- Frontal: Responsible for executive functions such as personality
- Parietal: Contains the somatic sensory cortex responsible for processing tactile information
- Temporal: Contains important structures such as the hippocampus (short term memory), the amygdala (behaviour) and Wernicke’s area (auditory perception & speech)
- Occipital: Processing of visual information
What are the folds in the cerebral hemisphere called?
Gyri- RidGes
Sulci- Valleys
What are the three parts of the brainstem?
Midbrain
Pons
Medulla
What is the cerebellum responsible for?
Fine tuning motor functions. Involved in balance and posture.
What are the 4 broad types of cells in the nervous system?
Unipolar- Has a cell body and one axon in one direction. Rarely found in the CNS. Mainly found around the retina.
Pseudo-unipolar - single axonal projection which splits into 2. Rarely found in the CNS, found in the pain pathway in the PNS.
Bipolar- 2 projections from the cell body. Rarely found in the CNS
Multipolar- COMMON
-Numerous projections coming from the cell body. Only 1 axon, rest are dendrites.
What are the three types of multipolar cells/shape?
Pyramidal- pyramid shaped cell body.
Purkinje cells- GABA neurones found in the cerebellum
Golgi Cells- GABA neurones found in the cerebellum
Describe the features of neurones and the common features they share.
- Excitable cells and heterogeneous morphology (lots of different types of cells)
- non-dividing cells
COMMON:
Soma (cell body)
- Nucleus and ribosomes- protein production
- Neurofilaments- type of IF provides structural support and transport
AXON
- Multipolar cell with only ONE axon.
- Can branch off into collaterals and it is myelinated
- responsible for the conduction of an AP
Dendrites:
- NOT myelinated
- receives signals from other neurones
- highly branched
What is the difference between axons and dendrites?
Axons are myelinated and dendrites are not There is only one axon but there are many dendrites
What are the features of astrocytes?
- not excitable
- Can proliferate
- Most abundant cell type in the mammalian brain
- Outnumber neuronal cells in the CNS
- star shaped
What are the functions of Astrocytes
- Structural cells , support by acting as a glue
- Facultative macrophages (turn into macrophages when they need to)
- Repair (provide nutrients for repair of neuronal cells)
- Homeostasis (mop up neurotransmitter and other substances released by the CNS)
What do oligodendrocyte do?
One oligodendrocyte myelinates MANY axons in the CNS. Glial cell produces the myelin.
What do schwann cells do?
Produce myelin for peripheral nerves.
One schwann cell myelinates ONE axon segment.
What are some differences between oligodendrocytes and astrocytes?
Oligodendrocytes are: Smaller
Denser cytoplasm and nucleus
Absence of intermediate filaments and glycogen in the cytoplasm
What do microglial cells do?
They are the immune cells of the CNS
What do ependymal cells do?
- epithelial cells of the CNS
- Line fluid filled ventricles: full of cerebrospinal fluid.
- Regulate production and movement of cerebrospinal fluid.
Name 5 different cell types found in the nervous system and provide details of their functions (10m)
- Neurone: excitable cells of the nervous system, responsible for electrical transmission
- Oligodendrocyte: A type of glial cells that produces myelin
- Schwann cell: myelin producing cells of the peripheral nervous system
- Astrocyte: structural cells involved in cell repair, neurotransmitter release & reuptake
- Microglia: Neuronal macrophages
- Ependyma: epithelial cells lining the ventricles
What is the usual resting membrane potential?
Between -40 and -90mV
Describe the ion distribution
High extracellular- Na+, Cl-
Low extracellular- K+
High concentration gradient for ca2+
Why does a Resting membrane potential exist
exists due to an ionic imbalance, high extracellular Na+ & high intracellular K+
What is saltatory conduction?
Action potentials jump between adjacent nodes of ranvier (instead of cable conduction) and so it speeds up action potentials
What can happen to Neurotransmitters when they dissociate from receptors?
- Metabolised by enzymes in synaptic cleft
- recycled by transporter proteins
What are the components of a neurone?
- Soma: cell body with the nucleus and intracellular organelles.
- Axon: thin outgrowth responsible for the conduction of an AP
- Dendrites: highly branched outgrowths of the stoma.
Which one of the following types of neurones has only one axonal projection from the cell body?
Bipolar
Multipolar
Pseudo-unipolar
unipolar
