Chapter 4.4 to 4.10 and chapter 12.1 to 12.3
- Able to recognize and name different types of nervous tissue and neural cells
- Able to explain the relation between shape and function of different types of
nervous tissue
- Able to explain the mechanism of synaptic communication
- Able to name the characteristics and functions of different types of glial cells
Nervous tissue
- Derived from ectoderm
- Central nervous system: brain and spinal cord
- Peripheral nervous system: the rest, e.g. in limbs and gut
- Afferent system (sensory information)
- Efferent system (motor commands)
Neuroglia (supporting cells)
- Maintain physical structure of tissues
- Repair tissue framework after injury
- Perform phagocytosis
- Provide nutrients to neurons
- Regulate the composition of the interstitial fluid surrounding neurons
Neurons have many different morphologies: the more complex the morphology, the more
complex the information they have to integrate.
Neuronal communication
- Neurons communicate
o With chemical messengers via synapses
o Via gap junctions (electrical synapses)
- Chemical messengers (neurotransmitters)
o Acetylcholine
o Amino acids (glutamine, GABA)
o Biogenic amines (serotonin, dopamine, adrenaline)
- These substances are in the axons (presynaptic) in vesicles and released after an
electric stimulus via exocytosis
- Results in activation of neurotransmitter receptors on the postsynaptic membrane
Skeletal muscle innervation: the neuromuscular junction
Schwann cells
- Sheath axons in the PNS
- Make the myelin sheath, which enhances conduction velocity of action potentials in
axons
- Nodes of Ranvier: for saltatory conduction (openings in between myelin sheets)
, Oligodendrocytes
- Predominantly present in white matter
- Formation of myelin sheet around neuronal axons in the CNS (comparable to
Schwann cells in the PNS).
- Can make myelin sheets on multiple axons
Microglia
- Microglial cells are present in both white and grey matter
- They are closely related to macrophages, (and are therefore classifies as connective
tissue, and not nervous tissue!)
- They can divide and migrate
- Their phenotype depends on their state of activation
Astrocyte function
- Structural support
- Neurotransmitter uptake from synaptic cleft (eg GABA, Glutamate)
- Ionic homeostasis
- Neuronal support: production of growth factors (eg NGF, BDNF)
- Response to injury/inflammation: phagocytosis, scar formation (gliosis)
- Part of Blood-Brain-Barrier (BBB)
Tight neuron-glia interaction in the CNS
- Glial cells take up transmitter that are spilled from the synapse (astrocyte)
- Able to recognize and name different types of nervous tissue and neural cells
- Able to explain the relation between shape and function of different types of
nervous tissue
- Able to explain the mechanism of synaptic communication
- Able to name the characteristics and functions of different types of glial cells
Nervous tissue
- Derived from ectoderm
- Central nervous system: brain and spinal cord
- Peripheral nervous system: the rest, e.g. in limbs and gut
- Afferent system (sensory information)
- Efferent system (motor commands)
Neuroglia (supporting cells)
- Maintain physical structure of tissues
- Repair tissue framework after injury
- Perform phagocytosis
- Provide nutrients to neurons
- Regulate the composition of the interstitial fluid surrounding neurons
Neurons have many different morphologies: the more complex the morphology, the more
complex the information they have to integrate.
Neuronal communication
- Neurons communicate
o With chemical messengers via synapses
o Via gap junctions (electrical synapses)
- Chemical messengers (neurotransmitters)
o Acetylcholine
o Amino acids (glutamine, GABA)
o Biogenic amines (serotonin, dopamine, adrenaline)
- These substances are in the axons (presynaptic) in vesicles and released after an
electric stimulus via exocytosis
- Results in activation of neurotransmitter receptors on the postsynaptic membrane
Skeletal muscle innervation: the neuromuscular junction
Schwann cells
- Sheath axons in the PNS
- Make the myelin sheath, which enhances conduction velocity of action potentials in
axons
- Nodes of Ranvier: for saltatory conduction (openings in between myelin sheets)
, Oligodendrocytes
- Predominantly present in white matter
- Formation of myelin sheet around neuronal axons in the CNS (comparable to
Schwann cells in the PNS).
- Can make myelin sheets on multiple axons
Microglia
- Microglial cells are present in both white and grey matter
- They are closely related to macrophages, (and are therefore classifies as connective
tissue, and not nervous tissue!)
- They can divide and migrate
- Their phenotype depends on their state of activation
Astrocyte function
- Structural support
- Neurotransmitter uptake from synaptic cleft (eg GABA, Glutamate)
- Ionic homeostasis
- Neuronal support: production of growth factors (eg NGF, BDNF)
- Response to injury/inflammation: phagocytosis, scar formation (gliosis)
- Part of Blood-Brain-Barrier (BBB)
Tight neuron-glia interaction in the CNS
- Glial cells take up transmitter that are spilled from the synapse (astrocyte)
