TOPIC VI: Nervous System IV – MOTOR “OUTPUT” Flashcards
What is the critical role of the motor nervous system?
Controlling most of the organs and physiological processes that keep a person alive and well, including walking, talking, heart rate, digestion and sweating.
What is required for coordinated responses to changes in the body’s internal or external environment?
The communication of information from the central nervous system to effectors like skeletal, cardiac, and smooth muscles, as well as many glands.
What are the two divisions of the motor nervous system?
Autonomic Nervous System (ANS) and Somatic Nervous System
How does the motor nervous system regulate bodily processes?
It regulates involuntary processes through the autonomic nervous system and controls voluntary movements through the somatic nervous system.
What is the function of the Autonomic Nervous System (ANS)?
Transmits signals from the CNS to autonomic effectors (smooth muscle, cardiac muscle, glands).
How many neurons are in the pathway from the CNS to the effector in the ANS?
Two: preganglionic and postganglionic
What are the two types of neurons in the ANS, distinguished by the neurotransmitters they release?
Cholinergic neurons, which release acetylcholine (ACh), and adrenergic neurons, which release norepinephrine (NE).
What is the function of the Sympathetic Nervous System (SNS)?
Prepares the body for activity; the “fight or flight” response, and is activated during exercise.
What are the two divisions of the Autonomic Nervous System?
Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PSNS).
What neurotransmitter does the preganglionic neuron release in the Sympathetic Nervous System (SNS)?
Acetylcholine (ACh); it is cholinergic.
What neurotransmitter does the postganglionic neuron typically release in the Sympathetic Nervous System (SNS)? What is the exception?
Typically Norepinephrine (NE); it is adrenergic. The exception is when the effector is a sweat gland.
How is acetylcholine (ACh) broken down after stimulating a postsynaptic cell?
By the enzyme acetylcholinesterase (AChE) on the postsynaptic membrane.
How is norepinephrine (NE) removed or broken down after stimulating a postsynaptic cell?
It is actively transported back into the synaptic end bulb of the neuron that released it and then broken down by the enzyme monoamine oxidase (MAO).
What is the function of the Parasympathetic Nervous System (PSNS)?
“Rest and digest” functions; “housekeeping”.
How do the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PSNS) typically affect the same organ?
Their effects are usually opposite to one another. For example, SNS increases heart rate, while PSNS decreases heart rate.
List the effects of the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PSNS) on the pupils of the eyes.
SNS dilates the pupils, while PSNS constricts them.
List the effects of the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PSNS) on the heart.
SNS increases heart rate and force of contraction, while PSNS decreases heart rate
List the effects of the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PSNS) on the gastrointestinal tract.
SNS decreases motility, while PSNS increases motility.
What is the effect of the Sympathetic Nervous System (SNS) on blood vessels?
Vasoconstriction. However, there is no innervation of blood vessels, except in the penis and clitoris.
What is the effect of the Sympathetic Nervous System (SNS) on sweat glands?
Increases secretion (cold sweat)
List the effects of the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PSNS) on digestive glands.
SNS decreases secretion (except saliva), while PSNS increases secretion (all of them)
List the effects of the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PSNS) on the genitals.
SNS causes ejaculation (male), while PSNS causes erection and lubrication (male and female).
What part of the brain has higher control of the ANS?
The hypothalamus.
Does the hypothalamus require cerebral input for its ANS functions?
No, there is no conscious control of the effectors. However, emotions can cause autonomic effects.
What is the function of the Somatic Nervous System?
Transmits signals from the CNS to skeletal muscle.
What are the three types of movement possible through the somatic nervous system?
Reflexes, voluntary, and rhythmic.
What are the two types of reflexes?
Spinal reflexes and postural reflexes.
What are the levels of motor control?
Planning, signaling directly to lower motor neurons, brain stem nuclei, and spinal cord.
What is the role of the cerebellum in motor control?
Planning and initiating movement, storing planned movements, comparing actual movements to the plan, and maintaining balance and muscle tone.
What is the role of the basal nuclei in motor control?
Aiding in planning movement, suppressing unwanted motions, and maintaining muscle tone.
What are the parts of the Corticospinal (Direct) Pathway?
Upper motor neurons and lower motor neurons.
What are the effects of the destruction of upper motor neurons?
Spastic paralysis and exaggerated reflexes, including the Babinski sign.
What are the effects of the destruction of lower motor neurons?
Loss of reflex arc and flaccid paralysis with muscle atrophy
What is the function of the language implementation system and what areas does it consist of?
Analyzes incoming and produces outgoing word sounds and grammatical structures. Consists of Wernicke’s area, Broca’s area, and basal nuclei.
What are the effects of damage to Wernicke’s area?
Poor language comprehension; can speak, but words are meaningless or mixed up.
What are the effects of damage to Broca’s area?
Can understand words, but it is difficult to speak or write sensibly (loss of motor control of speech).
