Neuroanatomy 1 Flashcards
Meninges - definition and names (3)
Three membranes of connective tissue that cover the brain and spinal cord
What two structures form the central nervous system?
Brain (encephalon) and spinal cord (Medulla spinalis)
What structures form the peripheral nervous system?
Cranial, spinal, and named nerves
Dura mater
Pachymenix: thickest and most external layer of the meninges
What are the main functions of the nervous system?
- General considerations:
- Informs animal about its environment
- internal and external environment
- Initiates responses to that environment
- Regulates and coordinates other systems
- e.g. locomotion, cardiovascular, digestion, respiration, circulation
- Informs animal about its environment
- Allows animal to interact, adapt and react to its environment
- Acts with and is also controled by the endocrine, immune, and sensory organs
What does ‘afferent’ mean in the context of the nervous system?
impulse towards the CNS
What does ‘efferent’ mean in the context of the nervous system?
impulse away from the CNS
What is the canal that the spinal cord runs through down the spine, and what parts of the vertebrae comprise this canal?
Vertebral canal
Vertebral foramina
How many cranial nerves (nerves that exit the brain) are there?
12 pairs
Spinal nerves are named according to which five regions?
- cervical
- thoracic
- lumbar
- sacral
- caudal
Through which gaps do paired spinal nerves leave the vertebral column?
Intervertebral foramina
How many pairs of cervical nerves are there?
8 pairs
What is a nerve plexus?
A branching network of intersecting nerves
The afferent system is composed of s___ (afferent) ___ (PNS) and the a_____ _____ (CNS)
The afferent system is composed of sensory (afferent) neurons (PNS) and the ascending pathway (CNS)
The efferent system is comprised of b_____ ____ (PNS) that may be:
- s_____ (lower motor neurons; usually under conscious control; locomotor system), or
- a________ (visceral, usually not under conscious control; organs, blood vessels, glands; sympathetic/parasympathetic).
The d______ ______ (CNS) is comprised of upper motor neurons.
The efferent system is comprised of motor neurons (PNS) that may be:
- somatic (lower motor neurons; usually under conscious control; locomotor system), or
- autonomic (visceral, usually not under conscious control; organs, blood vessels, glands; sympathetic/parasympathetic).
The descending pathway (CNS) is comprised of upper motor neurons.
What are the two basic cell types of the nervous system?
- Neurons
- Neuroglia (glial cells)
What are the four types of neuroglia and which broad part of the NS are they found in?
- Schwann cells (PNS)
- Oligodendrocytes (CNS)
- Astrocytes (CNS)
- Microglia (CNS)
What is the other term for the neuron cell body?
Perikaryon
What is the most prominent structure in the nucleus of a neuron and what is its primary function?
The nucleolus is a region found within the cell nucleus that is concerned with producing and assembling the cell’s ribosomes
Neurons have large amounts of ______ endoplasmic reticulum. These regions (rich in ribosomes, which make the cytoplasm of neurons stain quite darkly) are called ______ bodies/substance.
Neurons have large amounts of rough endoplasmic reticulum. These regions (rich in ribosomes, which make the cytoplasm of neurons stain quite darkly) are called Nissl bodies/substance.
Processes on neurons such as dendrites and axons are called _____.
Processes on neurons such as dendrites and axons are called neurites.
__________ are neurites that come off of the cell body, have a tapered shape, contain similar contents to the cell body, and are often quite short. they make up the ______ field, the signalling receptive zone of the neuron.
Dendrites are neurites that come off of the cell body, have a tapered shape, contain similar contents to the cell body, and are often quite short. they make up the dendritic field, the signalling receptive zone of the neuron.
The _______ is a neurite (process) coming out of the cell body that is narrow, often long, does not taper, can have collateral branches, has little ER (is pale staining), and is the signalling response zone.
The axon is a neurite (process) coming out of the cell body that is narrow, often long, does not taper, can have collateral branches, has little ER (is pale staining), and is the signalling response zone.
What are telodendria (sing. = telodendron)?
Distal branches of a neuronal axon that can further branch into axon terminals, each ending in a synaptic bulb.
What is a dorsal root ganglion?
Cluster of cell bodies of sensory nerves located in the posterior region of various vertebrae along the spinal column
What characterises a unipolar neuron? Give an example
One cell body and one process (axon)
- Stimulated by environment (sensory)
- Send the resulting impulse through a cell process directly to a muscle or gland cell
- e.g. Olfactory cells
- »fish not mammals
What characterises a bipolar neuron? Give an example
One cell body and two processes (axons)
- Retina of the eye
- Ganglia of cranial nerve VIII
- »Vestibulocochlear nerve
- Olfactory nerves of Mammals
What characterises a pseudounipolar neuron? Give an example
A pseudounipolar neuron has one axon that projects from the cell body for relatively a very short distance, before splitting into two branches — one that extends to the central nervous system, and the other that extends to the peripheral nervous system. Pseudounipolar neurons are sensory neurons that have no dendrites, the branched axon serving both functions
- Cell body appears to grow out to one side
- One process (axon) which branches
- Central and Peripheral branch
- Found within sensory ganglia of most cranial nerves
What characterises multipolar neurons? Give an example
Single cell body with many processes - one axon (axon hillock on cell labelled 4) and multiple dendrites
E.g. motor neurons
What is the term for sensory receptors at the terminal ends of sensory neurons that detect pain, heat, and cold?
Free Nerve Endings
What is the term for sensory receptors at the terminal ends of sensory neurons that detect cold specifically?
end bulbs
What is the term for sensory receptors at the terminal ends of sensory neurons that detect stretch?
stretch receptors
What is the term for sensory receptors at the terminal ends of sensory neurons that detect pressure and rapid vibrations?
Pacinian corpusles
What are the terminal endings of motor neurons called and what characterises them?
motor end plate
Neuromuscular junction - sits within skeletal muscke
Unmuelinated (bare axon at end)
Each Schwann cell membrane (with fatty substance) wraps around _____
Each Schwann cell membrane (M; with fatty substance) wraps around one axon
What is the term for the unmyelinated gaps at the junctions between two successive Schwann cells in the PNS that allow for saltatory conduction?
Nodes of Ranvier
Unmyelinated fibres in the PNS are still surrounded by ______ for protection.
schwann cells
(just not sheathed)
What is the term for the connective tissue sheath around a single nerve fibre?
endoneurium
What is the term for the connective tissue sheath around a bundle of nerve fibres (fasciculus)?
perineurium
What is the term for the connective tissue sheath around a nerve (bundle of fasciculi)?
epineurium
