The cerebral hemisphere is divided into what?
Lobes.
Frontal - front
Occipital - back
Temporal - side
Parietal - middle top
There are lots of folds?
Gyri - ridges
Sulci - valleys
Features of the Brainstem?
- Midbrain
- Pons
- Medulla
Lots of cranial nerves arise from this area, primarily grey matter (cell bodies)
Features of the Cerebellum
- Hindbrain structure attached to brainstem
- important in fine-tuning motor function
- involved in balance + posture
Features of the Spinal Cord
- Extends down from the medulla in the brainstem
- method of neural transmission
- co-ordinates some reflex actions.
Describe different neurons?
Unipolar:
- cell body
- one axon in one direction
- rarely found in CNS
Pseudo-unipolar:
- single axonal projection which splits into two
- rarely found in the CNS
- mainly found in the pain pathway in the PNS
Bipolar:
- Two projections from the cell body
- not found in the CNS
Multipolar: COMMON
- Numerous projections coming from the cell body
- one axon, rest dendrites
- Pyramidal cells, Purkinje cells, Golgi cells
Features of Neurones?
Excitable cells:
- can change membrane potential, send AP along their axons
Heterogenous Morphology:
- lots of different types
Non-dividing cells
Soma: Nucleus, Ribosomes, Protein production, Neurofilaments
Axon: Originates from soma at axon hillock, can branch off, Myelinated
Dendrites: Not myelinated, receives information.
What are Astrocytes?
- Neuroglia that outnumbers neuronal cells
- Not excitable
- Can proliferate
- Structural cell acts like glue
- For repair of neuronal cells
- Facultative macrophages - when necessary.
What are Oligodendrocytes and Schwann cells
- myelina generated by glial cells and extendsd spirals of membrane around the axons of many neurons
Oligodendrocytes –> for CNS
These cells are:
- smaller
- denser cytoplasm + nucleus
- absence of IF and glycogen in the cytoplasm
- one myelinates many axons.
Schwann cells:
- myelin for peripheral nerves.
- one schwann cell myelinates one axon segment
What are Microglial and Ependymal Cells?
Microglial Cells:
- Immune cells of the CNS
- Similar to macrophages
Ependymal cells:
- Epithelial Cells of the CNS
- Lines fluid filled ventricles - full of cerebrospinal fluid
- Regulates production and mvt of cerebrospinal fluid
What is the concentration of ions in neurons?
High Extracellular: Na+ and Cl-
Low Extracellular: K+
High concentration gradient into the cell of Ca2+ due to low concentrations inside the cell
What is the RMP of neurones?
-40 to -90mV
