Somatic nervous System Flashcards
Name the three main anatomical features of a neuron
cell body, dendrites & axons
Name the three different types of neuron
- bipolar
- Multipolar
- Pseudo unipolar
What is the difference between a bipolar, unipolar & pseudo unipolar neuron?
Bipolar- has a single axon at both sides of the cell body
multipolar- has many dendrites and a long axon
Pseudounipolar- has a single axon which exits the soma (cell body) and splits off into banches
What is the most common type of neuron?
Multipolar
Where in the body would you find pseudo unipolar neutrons?
Sensory ganglia of cranial and spinal nerves
What kind of nerve cells have a myelin sheath?
A myelin sheath is found on neurons of the CNS and PNS
Name the cells that make myelin in the PNS and CNS
Myelin is secreted by Schwann cells (glial cells) around some axons in the peripheral nervous system and by oligodendrocytes in the central nervous system
What is myelin made up of?
Myelin is a protein and lipid substance
What is the function of myelin?
Myelin increased velocity of impulse conduction (insulation)
Name the three coverings of peripheral spinal nerves and which part of the muscle they cover
- Epineurium (thick outer layer containing multiple nerve fascicles
- Perineurium (Covers individual nerve fascicles)
- Endoneurium (covers individual, myelinated nerves)
What name is given to blood vessels which surround nerves
vasa nervorum
What is a dermatome?
Dermatome= an area of skin supplied by a single spinal nerve
What is a myotome?
Myotome= Part of a muscle supplied by a single spinal nerve
What is a motor end plate?
Motor end plate=- The area that encompasses the end of the axon, the neuromuscular junction and the localised muscle tissue
What actions are the somatic nervous system responsible for?
- Somatic nervous system is responsible for general senses and voluntary movement (pain, heat, touch, proprioception).
- Stimuli are received at the periphery and taken to the CNS to be processed.
How many spinal nerves are there?
31 spinal nerves and 12 cranial nerves
all spinal nerves have a _______ and a _______ component.
All spinal nerves have a sensory and a motor component.
Spinal nerves that leave the spinal cord via the dorsal root and pass through the dorsal root ganglion innervate the _________ surfaces of the body
Spinal nerves that leave the spinal cord via the dorsal root and pass through the dorsal root ganglion innervate the posterior surfaces of the body. (e.g. the back, lower surface of the arm and back of the legs)
Spinal nerves that leave the spinal cord via the ventral root innervate the ______ surfaces of the body
Spinal nerves that leave the spinal cord via the ventral root innervate the anterior surfaces of the body (e.g. front of the torso, top surfaces of the arm, front of the legs)
Name the test that is used to assess the function of the quadriceps
Knee jerk
Which nerve is damaged in patients suffering from a wrist drop
The radial nerve
