T1L4 neural tissues Flashcards
cns vs pns
central ns:
- brain and spinal chord
- info processing
- reflexes and behaviour
peripheral ns:
- sensory detection
- motor activation
afferent vs efferent
afferent: sensory info to cns
efferent: motor info from cns to effector
ganglion
- group of cell bodies outside the cns
motor
sensory eg dorsal root ganglia
nucleus in cns
- group of neurons
directions in brains
rostral = towards nose caudal = towards tail medial = towards mid-sagittal plane dorsal = towards back of head and upwards ventral = opposite of dorsal
brodmann areas of neocortex
a brodmann area is a region of cortex
- there are 52 brodmann areas
- each has its own inputs and outputs
- often a brodmann area will have a function
neuron diagram
s12
neuron classification
multipolar, bipolar, unipolar
- all neurons have only one axon
multipolar = lots of dendrites bi = 2 mono = 1
3 important neurons
- pyramidal cell (neocortex)
- purkinje cell (cerebellum)
- dorsal root ganglion (sensory neuron)
pseudounipolar
- sensory neuron in pns
- one axon split into 2 branches
- one runs to pns other to spinal chord
- cell bodies form dorsal root ganglion
see s16
postsynaptic cell can be:
- neuron
- myocyte
- gland
convergent vs divergent
p self explanatory if you don’t mind me saying
divergent = a single neurons sends outputs to multiple neurons
convergent = multiple inputs influence one neuron
interneurons
- neither sensory or motor
- process signals
(relay neurons) - the brain is 80% interneurons
glia
- have no action potentials
- do not form synapses
- are able to divide (most common source of ns tumours)
- form myelin sheaths
- support and protect neurons
- there are many more glia than neurons
glial cell types
- ependymal cell
- astrocyte
- oligodendrocyte
- pia mater
- microglial cell
- Schwann cells (pns)
- satellite cells (pns)
oligodendrocyte
- produce and maintain myelin sheath in cns
- one cell can myelinate multiple axons
- Schwann cell equivalent
astrocyte
supports neurons:
- assists development and growth (neurotrophic)
- protects neurons from harmful substances
- influences blood flow and blood brain barrier
equivalent of satellite cells
microglia
immune cells
- protect neurons from disease
- migrate to injury site
- engulf microbes and debris
- from mesoderm
ependymal cells
- line brains ventricles and central canal of spinal chord
form csf
schwann cells
- PNS
- produce and maintain myelin sheath
- oligodendrocyte equivalent
- 1 cell wraps one axon
satellite cells
support neurons, regulate exchange of materials between neurons and interstitial fluid
- equivalent of astrocytes
meninges layers
- dura mater
- arachnoid
- pia mater
glioma
- largest group of primary tumours
- derived from glial cells
- usually very malignant
- rapid growth
- inside cranium and hard to remove surgically
neuroblastoma
- tumour
- most common in children
- outside cranium
- derived from neural crest sympathetic cells
survival rates vary depending on type
- survivors often develop neural problems 30 yrs later
