Lecture 6: The Role of the Nervous System in Movement Flashcards
neurons
signals from nerve cells which have both electrical and chemical components … the electrical currents are generated by the flow and differences in chemical ion concentrations … have three parts: the receiving end (have dendrites that bring messages into the cell), the cell body (contains nucleus of the neuron), the axon … mostly found in the CNS, but a few isolated regions, called ganlia, are found in the PNS
ions
charged compounds within body fluids and body cells
neurotransmitters
chemicals released by axons which can convey the message between one nerve cell and another or between a neuron and a muscle and can either stimulate or inhibit the next cell(s) in the line (here, that causes skeletal muscle to contract or relax)
central nervous system (CNS)
consists of two organs: the brain (a mass of neural tissue housed inside the cranial cavity of the skull) and the spinal cord (connected to the brain and housed within the vertebral column) … one of the two main components of the anatomical nervous system
peripheral nervous system (PNS)
made up of all other nerve tissue that extend off the brain or spinal cord … can be summarized as the nerves and structures called ganglia… one of the two main components of the anatomical nervous system
vertebral column
the bones and structures that make up the spine
cranial nerves
attached to the brain … bundles of axons wrapped in connective tissue and traveling together outside the CNS, and, therefore, a component of the PNS … usually relate to sensory input from the head, including special senses … 12 pairs come directly off the brain and exit the cranial cavity through foramina … nine of the 12 pairs of govern some of our voluntary skeletal muscles (all of which are wholly or partly in the head or neck) … there are three main types: those that are 1) entirely sensory in their function (i.e., those that relay the special senses of sight and hearing), 2) entirely motor which only control muscle (i.e., skeletal muscle, smooth muscle, cardiac muscle, or a combination of those), and 3) both sensory and motor and cover a myriad of functions (most in the head and neck)
olfactory nerve (CN I)
sensory … smell … one of the 12 pairs of cranial nerves
optic nerve (CN II)
sensory … vision … one of the 12 pairs of cranial nerves
oculomotor nerve (CN III)
motor … eye movement and pupil reflex … govern some voluntary muscles … one of the 12 pairs of cranial nerves
trochlear nerve (CN IV)
motor … eye movement … govern some voluntary muscles … one of the 12 pairs of cranial nerves
trigeminal nerve (CN V)
mixed … face sensation and chewing … one of the 12 pairs of cranial nerves
abducens nerve (CN VI)
motor … eye movement … govern some voluntary muscles … one of the 12 pairs of cranial nerves
facial nerve (CN VII)
mixed … face movement and taste … govern some voluntary muscles … one of the 12 pairs of cranial nerves
vestibulocochlear nerve (CN VIII)
sensory … hearing and balance … one of the 12 pairs of cranial nerves
glossopharyngeal nerve (CN IX)
mixed … throat sensation, taste and swallowing … govern some voluntary muscles … one of the 12 pairs of cranial nerves
vagus nerve (CN X)
mixed … movement, sensation and abdominal organs … one of the 12 pairs of cranial nerves
(spinal) accessory nerve (CN XI)
motor … neck movement … govern some voluntary muscles … one of the 12 pairs of cranial nerves
hypoglossal nerve (CN XII)
motor … tongue movement … govern some voluntary muscles … one of the 12 pairs of cranial nerves
spinal nerves
a bundles of axons wrapped in connective tissue and traveling together outside the CNS, and, therefore, a component of the PNS … formed when an anterior (ventral) root and a posterior (dorsal) root extend from the spinal cord and combine, just before exiting the vertebral column through intervertebral foramina … just after exiting, it divides into a ventral ramus and a dorsal ramus … all are mixed nerves, relaying both sensory and motor information … 31 pairs which carry sensation from and motor control to the trunk and limbs … named by their respective vertebrae (cervical, thoracic, lumbar spinal, sacral, coccygeal) … most carry sensations from the trunk and limbs and motor control to the trunk and limbs
cervical nerves
nerves extending from the spinal cord in the neck region … 8 of the 31 pairs of spinal nerves
thoracic nerves
nerves extending from the spinal cord in the area of the rib cage … 12 of the 31 pairs of spinal nerves
lumbar nerves
nerves extending from the spinal cord in the low back region … 5 of the 31 pairs of spinal nerves
sacral nerves
nerves extending from the spinal cord in the sacrum region … 5 of the 31 pairs of spinal nerves