Nervous Tissue Flashcards
It is the most complex system in the body, formed by a network of many billion nerve cells.
Nervous System
The network of many billion nerve cells are called _______.
Neurons
How does our nervous system provide rapid and precise communication between different parts of the body?
Through the action of specialized nerve cells called “neurons” and “glial” cells.
It is the supporting cell of the nervous system.
Glial Cells
They are responsible for the production and induction of electrical impulses.
Neurons and Glial Cells
Anatomical Division of the Nervous System
- Central Nervous System
- Peripheral Nervous System
Central Nervous System comprises of ________.
Brain and Spinal Cord
Peripheral Nervous System comprises of ___________.
- Cranial, Peripheral, and Spinal Nerves
- Ganglia
Aggregate of nervous cells
Ganglia
These are ovoid structures containing neuronal cell bodies, which acts as a relay station that allows the nerves to enter and leave simultaneously all the time.
Ganglia (Ganglion)
Functional Division of Peripheral Nervous System
- Afferent or Sensory Division
- Efferent or Motor Division
It carries messages from the sense organs and internal organs to the CNS.
Afferent or Sensory Division
Afferent or Sensory Division is subdivided into ________.
- Somatic Sensory Division
- Visceral Sensory Division
It carries messages from the sense organs (e.g., ears, skin, eyes) to the CNS.
Somatic Sensory Division
Somatic Sensory Division is perceived ________.
Consciously or Voluntarily
It carries messages from the internal organs to the CNS.
Visceral Sensory Division
Visceral Sensory Division is perceived _________.
Unconsciously or Involuntarily
It carries messages from the CNS to internal organs, glands, and muscles.
Efferent or Motor Division
Efferent or Motor Division is subdivided into ________.
- Somatic Nervous System (SNS)
- Autonomic Nervous System (ANS)
It carries messages to muscles under voluntary control.
Somatic Nervous System
It carries messages to organs and glands.
Autonomic Nervous System
Somatic Nervous System is controlled ________.
Consciously or Voluntarily
Autonomic Nervous System is controlled ________.
Unconsciously or Involuntarily
Two Pathways of ANS
- Preganglionic Neuron
- Postganglionic Neuron
The cell body is in the CNS.
Preganglionic Neuron
The cell body is in the Ganglion.
Postganglionic Neuron
Two Divisions of the Autonomic Nervous System
- Sympathetic
- Parasympathetic
It responds to impending danger or stress.
Sympathetic Division
SYMPATHETIC OR PARASYMPATHETIC.
- Increased heartbeat
Sympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Increased blood pressure
Sympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Increased sweat production
Sympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Dilation of Pupils
Sympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Sense of excitement
Sympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Fight or Flight
Sympathetic
It is called upon resting and relaxing situations.
Parasympathetic Division
SYMPATHETIC OR PARASYMPATHETIC.
- Conservation of energy
Parasympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Decreasing heart rate
Parasympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Decreasing respiratory rate
Parasympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Decreased pH of blood
Parasympathetic
SYMPATHETIC OR PARASYMPATHETIC.
- Constriction of Pupil
Parasympathetic
The basic functional unit of the nervous system is called ________.
Neurons (Nerve Cells)
Neurons generate electrical signals called ________.
Action Potentials
They allow neurons to transmit information over long distances.
Action Potentials
The Three Parts of the Neurons
- Cell Body (Perikaryon/Soma)
- Dendrites
- Axon
It contains the nucleus and organelles of the neuron.
Cell Body (Perikaryon/Soma)
Cell Body is also known as _______.
Perikaryon or Soma
_________ is the Tropic Center of the neuron.
Cell Body (Perikaryon/Soma)
The nucleus of a neuron is __________.
Euchromatic
The nucleolus of a neuron is __________.
Prominent
The neuron has a developed RER, which makes it ________.
Basophilic
The concentrated RER of a neuron is called ________.
Nissl Bodies (chromatophilic substance)
It forms the subunits of major intermediate filaments.
Neurofilaments or Neurofibrils
The inclusion of pigment materials, and a byproduct of lysosomal activity.
Lipofuscin
A specialized structure that receives stimuli from other neurons.
Dendrites
Where do dendrites receive stimuli?
Synapses
The principal signal reception site.
Dendrites
These are membrane protrusions along the small dendritic branches.
Dendritic Spines
This is where most synapses occur in the CNS.
Dendritic Spines
It generates and conducts nerve impulses to other cells.
Axon
Axons originated from the pyramid-shaped region of the perikaryon called the _________.
Axon Hillock
The plasma membrane of the axon is called _________.
Axolemma
The contents of the axolemma is called _________.
Axoplasm
Axoplasm contains _________.
Concentrated ion channels
What do the concentrated ion channels in the axoplasm do?
Generate action potentials
These are nerve impulses that travel along the axon.
Action Potential
These are sites where nerve impulses are transmitted from one neuron to another.
Synapses
Components of Synapses
- Presynaptic Axon Terminal
- Postsynaptic Cell Membrane
- Synaptic Cleft
This is where neurotransmitters are released via exocytosis.
Presynaptic Axon Terminal
It contains receptors for the neurotransmitter, and ion channels or other mechanisms to initiate a new impulse.
Postsynaptic Cell Membrane
It separates the presynaptic and postsynaptic membranes.
Synaptic Cleft
Classification of Neurons According to their Appearance
- Multipolar Neurons
- Bipolar Neurons
- Unipolar Neurons
- Anaxonic Neurons
1 Axon, >= 2 Dendrites
Multipolar Neurons
Most common classification of neurons (appearance)
Multipolar Neurons
1 Axon, 1 Dendrite
Bipolar Neurons
Sensory Neurons related to Bipolar Neurons
- Retina
- Olfactory Epithelium
- Inner Ear
- Adjacent CNS Neurons
It has a single process that bifurcates close to the perikaryon.
Unipolar Neurons
No true axon, many dendrites
Anaxonic Neurons
TRUE OR FALSE.
- Anaxonic Neurons do not conduct action potentials.
True
Why can’t anaxonic neurons conduct axon potentials?
Due to the absence of a true axon, which is where action potentials travel.
It regulates electrical changes.
Anaxonic Neurons
Classification of Neurons According to their Function
- Sensory Neurons (Afferent)
- Motor Neurons (Efferent)
- Interneurons
It receives stimuli from receptors throughout the body.
Sensory Neurons (Afferent)
It sends impulses to effector organs such as muscle fibers and glands.
Motor Neurons (Efferent)
Under voluntary control and typically innervate skeletal muscle.
Somatic Neurons
Control the involuntary or unconscious activities of glands, cardiac muscle, and most smooth muscle.
Autonomic Neurons
They establish relationships among other neurons, forming complex functional networks in the CNS.
Interneurons
Interneurons are either ________ or ________.
Multipolar or Anaxonic
Interneurons comprises ____% of all neurons in adults.
99%
The most numerous glial cell in the CNS.
Astrocytes
It covers and provides regulated microenvironment to the neurons.
Astrocytes
The _______ of the astrocyte contain proteins.
Proximal Region
Which protein can be found in the proximal region of astrocytes?
Glial Fibrillary Acid Protein (GFAP)
It serves as the unique marker for astrocytes.
Glial Fibrillary Acid Protein (GFAP)
It produces myelin.
Oligodendrocytes
It wraps the neuronal axon in both CNS and PNS.
Myelin Sheath
Myelin Sheath Functions
- Insulator
- Facilitates rapid transmission of nerve impulses
TRUE OR FALSE.
- Oligodendrocytes can be seen under routine light microscope stain.
False
The phagocytic cells in the CNS.
Microglia
They constitute the major mechanism for immunity in CNS.
Microglia
Microglia originated from _________.
Blood Monocytes
TRUE OR FALSE.
- The nuclei of microglia is visible with H&E and also with immunohistochemistry.
True
It assists in the production and circulation of cerebrospinal fluid (CSF).
Ependymal Cells
It lines fluid-filled cerebral ventricles and central canal of the spinal cord.
Ependymal Cells
__________ are epithelial-like cells which lacks basement membranes.
Ependymal Cells
Ependymal cells are usually ________ or ________ in appearance.
Columnar or Cuboidal
Neuroglia of the Central Nervous System
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal Cells
The counterpart of Oligodendrocytes.
Schwann Cells
It produces myelin sheath in the PNS.
Schwann Cells
Schwann Cells are also called as _________.
Neurolemmocytes
They exert a trophic or supportive effect on the neurons, insulating, nourishing, and regulating their microenvironments.
Satellite Cells
They enclose each perikaryon and regulates it microenvironment.
Satellite Cells
Neuroglia in the Peripheral Nervous System
- Schwann Cells
- Satellite Cells
The development of nerve tissue.
Neurulation
Neurulation is a critical morphologic event occurring during ________ of human gestation.
4th Week
The Three Germinal Layers from the Trilaminar Embryonic Disc
- Endoderm
- Mesoderm
- Ectoderm
Innermost layer
Endoderm
Middle layer
Mesoderm
Where the nervous tissue of the nervous system are derived from __________.
Ectoderm