4. Nerve tissue: Neurons (dendrites, axon,) and glial cells, synapses Flashcards
Neural tissue composed of ___ and ____
neurons and glial cells
Major function of neurons
active part, their major function is communication and transmitting information through electrical and chemical signals
Major function of glia
“inactive” participant to support and protect
Some Staning methods of neural tissue
„general” (HE)
Basic stainings (f.i. cresyl violet)
Golgi impregnation
silver impregnation (many types),
myelin stainings, filling up the cells, immunohstochemistry
Morphohlogy of neurons
Great pale nucleus, prominent nucleolus
basophil citoplasm
Rough endoplasmatic reticulum (rER) Nissl substance :not in the AIS nor in the axon
This is a neuron
-> Identify
Type of neuron?
Multipolar neuron-motoneuron in the spinal cord ventral horn
(Nissl staining, Réthelyi-Szentágothai book.)
Multipolar neuron-motoneuron in the spinal cord ventral horn
-> IDENTIFY
Classification of Neurons
-> Based on the mumber of processes
1 process: unipolar (amacrin cell in the retina)
2 processes: bipolar (retina and inner ear),
! pseudounipolar (semsory ganglions)
More than 2 = many: multipolar
Classification of Neurons
-> Based on shape, function, situation, neurotransmitter (specific)
fi.: Purkinje cells in cerebellum, Betz piramidal cells in cortex, dopaminerg cells in the substantia nigra etc.
Type of neuron?
Multipolar neuron-motoneuron in the spinal cord ventral horn
(Nissl staining , Röhlich’ book)
Multipolar neuron-motoneuron in the spinal cord ventral horn
(Nissl staining , Röhlich’ book)
-> Identify
Type of this neuron
-> Staining method?
Multipolar neuron-motoneuron in spinal cord
(Golgi AgNO3 impregnation, Réthelyi-Szentágothai tkv.)
Multipolar neuron-motoneuron in spinal cord
(Golgi AgNO3 impregnation, Réthelyi-Szentágothai tkv.)
-> Identify
Name of this type of neuron
Multipolar neurons in the cerebral cortex
Name of this type of neuron
Pseudounipolar neuron
What are the neuronal groups that can be found in CNS?
Nuclei
Multipolar neurons
Pseudounipolar in mesencephalic nucleus of trigeminal nerve
What are the neuronal groups that can be found in PNS?
Ganglions
Multipolars : vegetative ganglions
Pseudounipolar: spinal ggl.
What are the supporting cells that can be found in CNS?
Oligodendroglia cells, astrocytes
What are the supporting cells that can be found in PNS?
Satellite cells
In CNS, which cells can you find in myelin sheath?
Oligodendroglia cells
In PNS, which cells can you find in myelin sheath?
Schwann cells
What is Communication between neurons?
Synapse
What are the 2 types of synapses?
Electric and chemical synapses
Electric and chemical synapses
-> Width of synaptic gap?
E: 2.5 nm - 4 nm
C: 20 - 30 nm
Electric and chemical synapses
-> Which synapse has synaptic vesicles?
Chemical synapse
Electric and chemical synapses
-> Is the spread of depolarizazion fast or slow?
E: fast
C: slower
Electric and chemical synapses
-> How does AP transmission occur?
E: two ways
C: one way
Name this type of synapse. Why?
Chemical synapse because they have synaptic vesicle
How does chemical synapse occur?
How does Neurostransmision occur?
What are the 2 types of chemical synapse?
Type 1: Asymmetric
Type II: Symmetric
Describe type II (Symmetric) of chemical synapse
- Flat synaptic vesicles
- Thickness and postsynaptic membrane: even
- Generally inhibitory
Describe type I (Asymmetric) of chemical synapse
- light, round vesicles
- Thickness and postsynaptic membrane: different
- generally excitatory
What are the 2 different types of neurotransmitter receptors
- Ligand
- Ion channel
4 major excitatory receptors of ligand
- Acetylcholine (nicotinic receptor)
- Glutamate (NMDA class receptors)†
- Glutamate (non-NMDA class receptors)‡
- Serotonin (5HT3 class receptors)
4 major excitatory receptors of ion channel
- Na+/K+
- Na+/K+ and Ca2+
- Na+/K+
- Na+/K+
2 major inhibitory receptors
- Cl-
- Cl-
What is happening here?
Cocaine inhibits reuptake of neurotransmitters
What is happening here?
ECSTASY binds on transporter
Identify these Major glial cells
Identify these Major glial cells
What are the 2 types of astrocytes? Their locations?
astrocytes: fibrous (white matter) and protoplasmic (grey matter)
What is Perivascular glia limitans?
the outermost layer of nervous tissue of the brain and spinal cord, lying directly under the pia mater
Identify
Perivascular end-feet
What does blood brain barrier include?
This barrier also includes a thick basement membrane and astrocytic end-feet.
The blood–brain barrier occurs along all capillaries and consists of tight junctions around ____
the capillaries that do not exist in normal circulation.
blood brain barrier
-> Endothelial cellsrestrict the diffusion of (1)____, while allowing the diffusion of (2)___
- microscopic objects (e.g.,bacteria) and large or hydrophilic molecules into the cerebrospinal fluid(CSF)
- small hydrophobic molecules (O2, CO2, hormones)
Function of blood brain barrier
Protects the brain from many common bacterial infections.
Can antibodies and antibiotics pass through blood brain barrier?
Antibodies are too large to cross the blood–brain barrier, and only certain antibiotics are able to pass
What cannot pass through blood brain barrier?
Water-soluble stuff such as nutrients
(Amino Acids, Glucose, vitamins)
Polar stuff: Chemicals & toxins; Viruses; Bacteria
What can pass through blood brain barrier?
- Non-polar/ uncharged/ fat soluble stuff: this includes oxygen going in and carbon dioxide going out
- Drugs that are fat-soluble
- Other important stuff with special transporters embedded into the membrane to let them in, like water, glucose, amino acids, vitamins, etc.
- Ethanol crosses the blood-brain-barrier very easily
Can glucose pass through blood brain barrier?
We have special transporters to let f.i. glucose in: transporter will ONLY let glucose in.
The blood–brain barrier becomes more permeable during ___.
inflammation
What are the diseases when blood brain barrier is damaged?
Alzheimer’s disease
Cerebral edema: hipoxia
Prion and prion-like diseases
HIV encephalitis :circulatingmonocytesin the bloodstream (“Trojan horsetheory”)
Rabies
What are the diseases when blood brain barrier is damaged?
Alzheimer’s disease
Cerebral edema: hipoxia
Prion and prion-like diseases
HIV encephalitis :circulatingmonocytesin the bloodstream (“Trojan horsetheory”)
Rabies
What are Circumventricular organs?
Circumventricular organs(CVOs) are structures in the brain that are characterized by their extensive vasculature and lack of a normalblood brain barrier(BBB)
NAME Circumventricular organs
Different types of glial cells
- Microglia of Hortega
- Müllerian glial cells in the retina
- Bergmann glia in cerebellum
- Ependyma
- Tanicytes in median eminence
What are Tanicytes in median eminence?
Tanycytes are special ependymal cells found in the third ventricle of thebrain, and on the floor of the fourth ventricle and have processes extending deep into the hypothalamus.
Function of Tanicytes in median eminence?
their function is to transfer chemical signals from the cerebrospinal fluid(CSF) to the central nervous system(CNS). .
Identify
Identify
-> Type of staining
Nodes of Ranvier
-> Golgi AgNo3 impregnation ,Réthelyi-Szentágothai book
What are the 3 layers of peripheral nerve?
-epineurium
-perineurium (p)
-endoneurium (e)
Identify
Peripheral nerve HE staining
-epineurium
-perineurium (p)
-endoneurium (e)
This is a cross section of peripheral nerve
-> Identify
Blue - Schwann cell’s nucleus
Black - axon
Red - Myelin sheath
This is a cross section of peripheral nerve
-> Identify
Myelin sheath
This is longitudinal section of peripheral nerve
-> Identify
Blue - Schwann cell’s nucleus
Black - axon
Red - Myelin sheath
What is Glymphatic system?
a recently discovered macroscopic waste clearance system that utilizes a unique system of perivascular channels, formed by astroglial cells, to promote efficient elimination of soluble proteins and metabolites from the central nervous system.
-> Discovering novel strategies for optimizing and maintaining efficient brain waste clearance across the lifespan may in the future prove to be important for preventing cognitive decline and sustaining healthy aging.
Classification of nerve fibers
