Anatomy Study Guide Chpt. 7B- Sara Fusco
Terms in this set (29)
Describe the PNS.
The peripheral nervous system (PNS) consists of nerves and scattered groups of neuronal cell bodies (ganglia) found outside the CNS.
Explain the layering of a nerve from inner to outer covering.
Each fiber is surrounded by a connective tissue sheath, an endoneurium. Groups of fibers are bound by a coarser connective tissue wrapping, the perineurium, to form fiber bundles, or fascicles. All the fascicles are bound together by a tough fibrous sheath, the epineurium, to form the cordlike nerve.
What are mixed nerves?
Mixed nerves carry both sensory and motor fibers; all spinal nerves are mixed nerves.
How many cranial nerves do humans have?
How are cranial nerves numbered and named?
Cranial nerves are numbered in order, and their names reveal the most important structures they control
What three nerves are sensory nerves only?
The optic, olfactory, and vestibulocochlear nerves are purely sensory
How are spinal nerves named?
Spinal nerves are named for the regions of the spinal cord from which they arise
What are dorsal and ventral rami?
Each spinal nerve divides into dorsal and ventral rami, making each nerve only about half an inch long/ the rami contain contain both motor and sensory fibers. The dorsal rami serve the skin and muscles of the posterior body trunk. The ventral rami of spinal nerves form complex networks of nerves called plexuses, which serve the motor and sensory needs of the limbs.
What is a plexus?
The ventral rami of spinal nerves form complex networks of nerves called plexuses, which serve the motor and sensory needs of the limbs.
Describe the autonomic nervous system.
The autonomic nervous system (ANS) is the motor subdivision of the PNS that controls body activities automatically. The ANS is composed of a specialized group of neurons that regulate the cardiac muscle, smooth muscles, and gland. The relative stability of the body is due to the ANS.
What is another name for the autonomic nervous system?
The involuntary nervous system
How are the somatic and autonomic nervous systems different in terms of neurons?
The somatic nervous system has one type of neuron that is located insisted the CNS and their axons extend all the way to the skeletal muscles.t eh autonomic nervous system has 2 motor neurons.
Explain how an impulse would flow front eh autonomic nervous system.
The first motor neuron, the preganglionic neuron, is in the brain or spinal cord, the preganglionic axon leaves the CNS to synapse with the second motor neuron. The second motor neuron, the ganglionic neuron, is in a ganglion outside the CNS, the postganglionic axon extends to eh organ it serves.
What are the two divisions of the ANS?
The autonomic nervous system has two branches, the sympathetic and parasympathetic.
Which division is responsible for the "fight or flight" response?
What is the neurotransmitter parasympathetic fibers release?
Parasympathetic fibers, called cholinergic fibers, release Acetylcholine
What is the neurotransmitter the sympathetic fibers release?
Sympathetic fibers, called adrenergic fibers, release norepinephrine
When is the parasympathetic nervous system most active?
It is most active when he body is at rest and not threatened in any way
What functions does the parasympathetic regulate?
It is concerned with promoting normal digestion, conserving body energy, and decreasing demands on the cardiovascular system
When does the nervous system form during embryonic development?
The nervous system is formed during ht first month of embryonic development
Describe cerebral palsy.
Temporary lack of oxygen during delivery may lead to cerebral palsy. Cerebral palsy is a neuromuscular disability in which the voluntary muscles are poorly controlled and spastic because of brain damage. About half of its victims are mentally retarded or have impaired hearing or vision.
What is anencephaly?
Anencephaly is the failure of the cerebrum to develop, resulting in children who cannot hear, see, or process sensory inputs
Describe spina bifida.
Spina bifida results when the vertebrae form incompletely.
When does your brain reach its maximum weight?
The brain reaches its maximum weight in the young adult.
What happens to the weight of the brain after it reaches its maximum weight
after it reaches its maximum weight the brain steadily loses weight and volume
Why do older people get light headed when they stand up?
The sympathetic nervous system gradually becomes less and less efficient, as you age. Old people get light headed after standing because of the inefficiency of the sympathetic nervous system on the blood vessels. This condition is known as orthostatic hypotension.
Arteriosclerosis and high blood pressure result in a decreasing supply of oxygen to the brain neurons
What is senility?
Senility is a result of a gradual lack of oxygen due to aging
What are the characteristics of senility?
Senility is characterized by forgetfulness, irritability, difficulty in concentrating and thinking clearly, and confusion