Midterm 4 Flashcards
Peripheral nervous system injury & repair Spinal cord and brainstem lesion
Neurons in the cerebral cortex and brainstem that govern the activity of lower motor neurons in the brainstem and spinal cord
Upper motor neurons
Alpha motor neurons innervate intrafusal muscle fibers for muscle contraction, true or false?
False, alpha motor neurons innervate extrafusal muscle fibers for muscle contraction
Alpha motor neurons = extrafusal
Gamma motor neurons innervates intrafusal muscle fibers (muscle spindles), true or false?
True
Gamma motor neurons = intrafusal
Innervate extrafusal muscle fibers for muscle contraction
Alpha motor neurons
Innervate intrafusal muscle fibers (muscle spindles)
Gamma motor neurons
Somatic motor lower motor neurons are alpha motor neurons, true or false?
True
The cell body of somatic motor neurons is located where?
Anterior/ventral horn
Cervical and lumbosacral enlargements in the spinal cord are to accommodate for…
Extra motor units for the limbs
Axons of the somatic motor neurons in the spinal cord form the _________________ root.
anterior/ventral root
Axons of the somatic lower motor neurons join posterior/dorsal sensory roots to form the ___________________ for each spinal level.
Spinal nerve
Cranial nerve lower motor neurons originate in the ________________.
Brainstem
The alpha motor neuron and the skeletal muscle fibers it innervates together form the ___________________.
Motor unit
Spinal nerves are made up of posterior (sensory) roots and anterior (motor) roots. Spinal nerves split to become posterior and anterior ________________. Anterior ________________ at various levels combine to become trunks of the brachial and lumbosacral plexi. Ultimately, separate to terminal branches called _______________________.
Rami
Peripheral nerves
Efferent =
Afferent =
Efferent = motor
Afferent = sensory
A _______________ is an area of skin that is mainly supplied by afferent nerve fibers from the dorsal root of a spinal nerve.
dermatome
Clinically, there is overlap between the dermatomes, the borders are not as distinct as it seems in textbooks, true or fale?
True
Terminal branches of the peripheral nervous system are called…
Peripheral nerves
Peripheral nerves are a collection of axons surrounded by _________________.
connective tissue layers
Peripheral nerves are mixed (motor and sensory), true or false?
True
Cranial nerves are not peripheral nerves, true or false?
False, cranial nerves are peripheral nerves
Damage to the descending tract BEFORE the anterior horn of the spinal cord is referred to as:
Upper motor neuron syndrome
Damage to alpha motor neuron at or distal to the anterior horn is referred to as:
Lower motor neuron syndrome
Upper motor neuron lesions refer to damage where?
Before/proximal to the anterior horn
Lower motor neuron lesions refer to damage where?
At or after/distal to the anterior horn