Nervous tissue Flashcards
what is the function of the nervous system
To provide rapid the precise communication between different parts of the body via the action of neurones
What is the function of the central nervous system
EX brain and spinal cord
The central nervous system is where information processing occurs. It integrates, processes and coordinates sensory input and motor commands.
What are the receptors in the nervous system and their focus
RECEPTORS:
Special sensory receptors
-monitor smell, taste, vision, balance and hearing
Visceral sensory receptors
-monitor internal organs
Somatic sensory receptors
-monitor skeletal muscles, joints and skin surface
What are the subdivisions of the autonomic nervous system
-Parasympathetic division (Waste & digestion processes)
-Sympathetic division (Sudden or Immediate action/fight or flight)
Both consist of Smooth muscle, Cardiac muscle, Glands
Only sympathetic includes Adipose tissue
What does the peripheral system consist of
Nervous tissue outside the CNS and the ENS
Overview of the nervous system
RECEPTORS:
Special sensory
Visceral sensory
Somatic sensory
Sensory info within afferent division
CNS - Information processing
Motor commands within efferent division
Somatic nervous system - skeletal muscle / autonomic nervous system - Parasympathetic and sympathetic divisions
Cells of the nervous system
Neurones (nerve cells) and glial cells (support cells)
What is the functional unit of the nervous system
Nerve cells - send signals around the body
How is a neuron specialised for intercellular communication
Long lived cells with high metabolic rate
Dendrites - highly branched processes site at which neurons receive info
Large cell bodies - larger than other cells
Single axon - extends away from cell body can reach up to 1 metre in length rapidly propagates action potentials
Terminal boutons - form communication junctions with other cells in pathway (synapses)
Excitability - small difference in charge between inside and outside of cell
What are dendrites
Highly branched processes extending from the cell body which form synapses with adjacent neurons and respond to external stimuli to convey incoming information to the cell body.
How is the cell body of a neuron different from that of other cells
Larger nucleus (stains darker)
Prominent nucleolus is a sign of active and ongoing synthesis of ribosomes. Reflects high metabolic demands placed on neurons
Nissl bodies (Name for clusters of rough endoplasmic reticulum)
Numerous mitochondria
Grey matter - colour from high density of Nissl bodies
What is the function of axons
Rapidly propagates signal from cell body towards axon terminals
Specialised to conduct action potentials
PNS - myelinated or non-myelinated
CNS - myelinated
Terminal boutons
Form synapses with other neurones or effector organs
Communications junctions e.g. neuromuscular junctions
Here electrical signals are converted to chemical signals
neurotransmitters released and convey message to next cell in pathway.
Types of Neuroglia cells (glial cells) protection and support neurones
CNS
-ependymal cells
-astrocytes
-microglia
-oligodendrocytes
PNS
-satellite
-schwann cells
What forms almost half of the total mass of the CNS
Neuroglia cells
structure and function of ependymal cells
Simple ciliated cuboidal epithelium
Lines fluid-filled cavities in brain (ventricles) and spinal canal
No basement membrane, long processes which merge with underlying tissue
Function
Help to move spinal fluid around and regulate composition of spinal fluid
What is the structure and function of astrocytes
Structure
Named for star shape
Highly branched
Large and numerous (most numerous support cell in CNS)
Form the blood-brain barrier
Function
provide mechanical support
mediate the exchange of metabolites between neurons and vascular system
Regulate chemical environment
What is the structure and function of microglia
Structure
Named for small size
Derived from phagocytes and macrophages so have phagocytic capacity
Function
In response to tissue damage they will transform into large phagocytic cells as to remove invading microbes and dead cells from the CNS
White and grey matter
Cell bodies of neurons are mainly located within grey matter while white matter consists mainly of the myelinated neuronal axons (oligodendrocytes)
Function of Oligodendrocytes
A single oligodendrocytes can contribute to the myelination of up to 50 axons however every axon must derive its coat from numerous oligodendrocytes as permitted length is limited from each.
They provide structural, functional and metabolic support to axons
Predominant neuroglia of white matter
How do Schwann cells provide structural and metabolic support
They are the equivalent of oligodendrocytes as they form the myelin sheaths around the PNS axons.
Smaller non myelinated axons are enveloped by the cytoplasm of Schwann cells providing protection.
Larger diameter axons are wrapped by the Schwann cell membrane to create a myelin sheath.
What are ganglions
Aggregations of neuronal cells bodies that are located near the spinal column
Where are satellite cells located
In ganglions
What is the structure and assumed of satellite cells
Flattened cells that cover the surface of neuronal cell bodies
Provide structural and functional protection to neuronal cell bodies
What type of neuroglia lines the spinal canal
Ependymal cells
Which type of neuroglia forms part of the blood-brain barrier
Astrocyte
The structure of neurons is designed to reflect their function of….
intercellular communication
What is the function of the neuronal axon
Propagate action potentials
What type of epithelium do ependymal cells have
Simple ciliated cuboidal epithelium
Which neuron is found in the cerebral cortex
Pyramidal
What are nissl bodies
Clusters of rough ER
Which one of these cells of the neuroglia is not associated with the CNS
Satellite cells
Which cells are responsible for the removal of invading microbes and dead cells from central nervous system
Microglia
How many pairs of lumbar nerves are present in spinal nerves?
5
Vitamin B12 is produced within the gastrointestinal tract to aid with function of the nervous system as well as keeping our blood cells healthy. Which cell in the gastrointestinal tract produces intrinsic factor, the protein that helps with the absorption of this vitamin
Parietal cells
What is the function of epidymal cells?
Secrete cerebro spinal fluid and its movement
What is the function of neuroglial cells
Protection and support of the nervous system
What is the layer of thin connective tissue that wraps around individual muscle fibres
Endomysium
What is an alternative name for nerve fibres?
Axon
What is the perikaryon
Another name for the cell body of the neuron
What is the function of the nodes of Ranvier?
Enhances the conduction
velocity of axons
Allows nutrients and
waste to enter and exit the neuron.
What stain colours lipids
Osmium tetroxide
What does calibre mean
Calibre refers to the diameter of the axon
How can the effectiveness of local anaesthesia
be affected by the presence of adipocytes?
The potency of an anaesthetic is associated with its lipid solubility.
In which direction does information typically travel in the ventral horns?
Downwards
What type of neurons are located at the small lateral horns
Sympathetic efferent neurons
What neurons are found in the human cerebellum
Pirkinje cells
What are Ganglia
Clusters of neuron cell bodies which house millions of synapses
