Cells and tissues of the nervous system Flashcards
PNS consists of (2)
Cranial nerves
Spinal nerves
What fibres do spinal nerves carry (4)
Sensory
Somatic motor
Autonomic motor
- sympathetic
- parasympathetic
2 cell types making up the nervous system
Neurons
Glia/ glial cells
Are glial cells excitable
No
Typical neuron consists of (4)
MULTIPLE DENDRITES, 1 CELL BODY, 1 AXON & SYNAPTIC TERMINALS
What is the cytoplasm of the cell body of a neuron known as
What is the cytoplasm of the axon of a neuron known as
Perikaryon
Axoplasm
Do neurons proliferate by mitosis
No, they proliferate by amitosis (unusual form of cell division in which the nucleus and cytoplasm divide by constriction without the formation of chromosomes)
Are neurons or glia bigger
Neurons
Axons may or may not be covered in a
Myelin sheath
Purpose of a myelin sheath
Increase conduction speed by saltatory conduction
Myelin sheath is formed by what type of glial cell
- in the PNS
- in the CNS
PNS - Schwann cells
CNS - oligodendrocytes
3 types of neurons
Multipolar - e.g. motor neurons
Bipolar
Pseudounipolar - e.g. sensory neurons
What type of neurons are motor neurons
Multipolar
What type of neurons are sensory neurons
Pseudounipolar
Name 6 types of glial cells + which of these are in the CNS (4) and the PNS (2)
CNS: Astrocytes Oligodendrocytes Microglial cells Ependymal cells
PNS:
Schwann cells
Satellite cells
Most abundant glial cell in the CNS
Astrocytes
2 functions of astrocytes
Provide structural and biochemical support to neurons
Forms part of BBB (due to its end feet projections)
Function of microglia
Phagocytosis
Function of ependymal cells (a type of glial cell)
Line ventricles
What is grey matter composed of
Cell bodies of neurons
Focused collections of neuronal cell bodies are called in the CNS
nuclei
Focused collections of neuronal cell bodies outside the CNS are called
ganglia, e.g. DRG
Function of the BBB
SEMIPERMEABLE membrane allowing passage of water, some gases, and hydrophobic (O2, CO2) molecules by passive diffusion, as well as the selective transport (transport protein required) of molecules such as glucose and amino acids
Circumventricular organs are those that lack a
BBB
They have a highly permeable microvasculature
Where are circumventricular organs found
Midline structures around the third and fourth ventricles
Drugs entering brain have to be … … or use suitable … or else it can’t cross the BBB
lipid soluble
vectors
What special feature do astrocytes have
Long end feet projections that surround synapses & capillaries
BBB consists of (3)
- Tight junctions between endothelial cells
- Thick basal lamina
- Endfeet of astrocytes that surround endothelial cells
CSF is found where (3)
VENTRICLES
CENTRAL CANAL OF SPINAL CORD
SUBARACHNOID SPACE
CSF protects the brain by providing…
buoyancy which prevents the weight of the brain from compressing the cranial nerve roots and blood vessels against the internal surface of the cranium
3 layers of meninges
Dura
Arachnoid
Pia
Which layer of the meninges is vascularised
Pia
