Concept explainers
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
a. The somatic sensory division of the PNS detects sensory stimuli from the organs in the thoracic and abdominopelvic cavities.
b. The somatic motor division of the PNS consists of lower motor neurons that directly innervate skeletal muscle fibers.
c. The visceral motor division is also known as the autonomic nervous system and maintains homeostasis of many physiological variables.
d. The term nerve is the equivalent of the term neuron.
e. There are 31 pairs of spinal nerves and 12 pairs of cranial nerves.
To review:
Whether the following statements are true or false:
1. The somatic sensory division of the PNS detects sensory stimuli from the organs in the thoracic and abdominopelvic cavities.
2. The somatic motor division of the PNS consists of lower motor neurons that directly innervate the skeletal muscle fibers.
3. The visceral motor division is also known as the autonomic nervous system and maintains homeostasis of many physiological variables.
4. The term ‘nerve’ is the equivalent of the term ‘neuron’.
5. There are 31 pairs of spinal nerves and 12 pairs of cranial nerves.
Introduction:
The peripheral nervous system acts as a link which bridges the CNS (central nervous system) with the body and outer environment. In order to link them, it first detects the sensory parts of the stimuli and carries them to the CNS as a sensory input. The CNS works on the input and then distributes the impulses by means of the PNS (peripheral nervous system) to the effectors to generate a motor output. In this case, the effectors are the muscle cells and glands.
Explanation of Solution
a. The statement “The somatic sensory division of the PNS detects sensory stimuli from the organs in the thoracic and abdominopelvic cavities”is false. The correct statement is the somatic sensory division of the PNS detects sensory stimuli from the structures of musculoskeletal system. In fact, they detect the stimuli from the skin and structures of the musculoskeletal system.
b. The statement “The somatic motor division of the PNS consists of lower motor neurons that directly innervate skeletal muscle fibers” is true. In the true sense, the somatic motor division of the PNS consists ofa lower type of motor neurons which are in direct contact with the skeletal muscle fibers.
c. The statement “The visceral motor division is also known as the autonomic nervous systemwhichmaintains homeostasis of many physiological variables” is true. The visceral motor division is also known as the autonomic nervous system which maintains the homeostasis state of many variables which are physiological in nature by controlling the involuntary motor functions of the body.
d. The statement “The term nerve is the equivalent of the term neuron” is true. It is foundthat a nerve contains numerous neurons which are connected to each other by a tissue.
e. The statement “There are 31 pairs of spinal nerves and 12 pairs of cranial nerves” is true. It widely known that there are 31pairs of spinal nerves and 12 pairs of spinal nerves in the human body.
Thus, it can be concluded that the statements(b), (c),(d) and(e) are true according to the reasons provided and the statement (a) is false.
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Chapter 13 Solutions
HUMAN A+P MOD.MASTERING
- Sensory neurons transmit information towards the central nervous system. Which of the following is true concerning the movement of peripheral- information towards the central nervous system? A. Dendrites of the sensory neurons synapse with interneurons of the spinal cord. B. Axons of the sensory neurons synapse with motor neurons of the muscles involved in the spinal reflex. C. Axons of the motor neurons synapse with the interneurons of the spinal cord. D. Axons of the sensory neurons synapse with the interneurons of the spinal cord.arrow_forwardAll of the following are true regarding the descending motor tracts EXCEPT which one? A. They originate in either the cerebral cortex or brainstem. B. The pathways are generally made of a two-neuron system. C. The upper motor neuron fibers target lower motor neurons of the spinal cord or cranial nerves. D. They are involved in assisting with voluntary movement.arrow_forwardWhich of the following statements regarding sciatic nerve is correct? a. Arises from L3/4/5/S1/2 b. Emerges from the lower border of piriformis c. Most commonly divides onto common peroneal and tibial branches in the middle of the hamstring compartment d. Can be injured by intramuscular injections in the upper outer quadrant of the buttock e. Gives no branches in the gluteal compartmentarrow_forward
- Mark the following statements on the role of the brain in movement as true or false. If a statement is false, correct it to make a true statement. a. The dopaminergic neurons of the substantia nigra enhance the actions of the caudate nucleus and putamen. b. The cerebellum monitors the initiation of movement but does not monitor ongoing movements. c. The basal nuclei inhibit inappropriate movements and are required for the initiation of movement. d. The correction of motor error by the cerebellum can occur over the long term by motor learningarrow_forwardWhich of the following is NOT a reason why a reflex arc is faster than a normal nerve transmission? a. A reflex arc stimulates the motor neurons for an immediate reaction. b. A reflex arc does not send information to the brain to be processed. c. A reflex arc does not involve neurotransmitters. d. A reflex arc involves fewer neurons.arrow_forwardFill in the blank for A and B A. The vagus nerve is a so-called cranial nerve- it exists and enters the brain. It contains ___ (pre or post) ganglionic fibers of the __________ (parasympathetic or sympathetic) autonomic nervous system. B. Ascending tracts carry ______ (sensory or motor) information. C. The nervous tissue is derived from which germ layer?arrow_forward
- A typical spinal nerve: Select one: a. normally divides into four branches that will supply the thoracic region, the abdominal region, the pelvic region and the limbs b. is covered by the connective tissue called epineurium c. attaches to the spinal cord via the dorsal root ganglia d. is protected by the dura, arachnoid and pia mater e. contains one nerve fibre and it's myelin sheatharrow_forwardAmong the followings which does not indicate the stimulation of parasympathetic system? A. Contriction of skeletal muscle blood and vasodilation of renla blood B. Excitation of the blood flow to the kidneys and smooth muscles of Gl tract C. Inhibition of heart rate and amooth muscles of the urinary bladder Excitation of the smooth muscles of the urinary bladder and Gl tractarrow_forwardA typical spinal nerve: Select one: is protected by the dura, arachnoid and pia mater b. normally divides into four branches that will supply the thoracic region, the abdominal region, the pelvic region and the limbs C. contains one nerve fibre and it's myelin sheath d. is covered by the connective tissue called endomysium e. attaches to the spinal cord via the dorsal and ventral roots O a.arrow_forward
- Study the diagram of a synapse between a sensory neuron and a motor neuron in a simple reflex arc involving only two neurons. Use the information provided by the diagram to answer the questions. 60 mV 2- +40 mv 3. d. -60 mV + 40 mV f 1. If the neurotransmitter substance was acetylcholine, describe two places where this synapse might be found in the body. Answer: From the diagram, identify where receptors for the neurotransmitter would be located. Explain your answer. 2. Answer: 3. Which letter indicates the axon of the sensory neuron? Justify your answer. Answer: 4. Identify where an action potential is occurring. Justify your answer. Answer: What structure is represented by the letter F? What is the function of F? What effect does F have on the transmission of action potentials along the neuron? 5.arrow_forwardDescribe the function of the following types of neurons a. Sensory neurons (also known as ____________ neurons): b. Motor neurons (also known as ____________ neurons): c. Interneurons (also known as ____________ neurons):arrow_forwardHyporeflexia occurs when normal reflexes are weak but not absent. Damage to which of the following would result in hyporeflexia? Hyporeflexia occurs when normal reflexes are weak but not absent. Damage to which of the following would result in hyporeflexia? A.Motor neuron B. Sensory neuron C.Skeletal muscle D. Any of the choices would result in hyporeflexia. Which option to select..arrow_forward