Human Anatomy and Physiology - Problem Drill 11: Neural Tissue & The Nervous System

Transcription

1 Human Anatomy and Physiology - Problem Drill 11: Neural Tissue & The Nervous System Question No. 1 of 10 The human body contains different types of tissue. The tissue is formed into organs and organ systems. Which of the following is correct about neural tissue in the body? Question #01 A. There are a total of 5 main types of tissue in the body, neural tissue being one of them. B. Muscle tissue is arranged in sheets, one or more layers thick. C. There is no neuroglial cells in the peripheral nervous system. D. Neuroglial cells protect and support the neurons in the nervous system. E. None of the answers are correct. There are a total of 4 main types of tissue in the body. Muscle tissue contains sarcomeres and muscle fibers. There are neuroglial cells in the central and peripheral nervous systems. D. Correct! Neuroglial cells protect and support the neurons in the nervous system. One of the answers is correct. Cells are organized into tissues within the human body and, together, tissues make up body organs. There are four types of tissue: (1) Epithelial - Epithelial tissue is made of different cell types organized into a sheet with one or more layers. An epithelium consists mostly of cells with little extracellular material between adjacent plasma membranes. (2) Connective tissue is the most abundant body tissue. It consists of cells and a matrix of ground substance and fibers; (3) Muscle tissue generates the force used by the axial skeleton for movement. Through the attachment on bones and lever action, muscle provides for movements of limbs and the head and neck, and (4) The nervous system is composed of neurons (nerve cells) and neuroglia (protective and supporting cells). Neuroglia are found in the central and peripheral nervous system.

2 Question No. 2 of 10 Which part of the neuron is labeled in the image below? A Question #02 A. Terminal boutons. B. Axon. C. Soma. D. Dendrite. E. Dendritic tree. A. Correct! The terminal boutons are labelled in the image. The axon ends in the terminal boutons but, in the image, the terminal boutons are labelled. The soma is the nerve cell body, and it is attached to the axon and dendrite. The dendrites are attached to the soma of the neuron. The dendrites of the neuron can make up a dendritic tree; the label in the image is pointing to the terminal boutons. The nervous system is made up of neurons (neuronal cells), which conduct signals from the brain to the rest of the system; it also consists of glial cells, which support neuronal function. The neuron is specialized for receiving signals (at the dendrites and cell body), propagating electrical impulses (down the axon), and transmitting signals (at the terminal branches).

3 Question No. 3 of 10 Which of the following statements about the labelled portion of the image below is correct? A Question #03 A. This portion of the neuron only receives information from another neuron. B. The letter A in the image is pointing to the soma. C. This portion of the neuron can be myelinated. D. The flow of information along this portion of the neuron is from the terminal boutons towards the cell nucleus. E. There are no neuroglial cells around this portion of the neuron. The axon that is labelled in the image transmits information from the soma to the terminal boutons and synapses. The letter A in the image is pointing to the axon. C. Correct! The axons of certain neurons are myelinated. The flow of information along the axon is from the soma towards the terminal boutons. Even in an unmyelinated axon, there are neuroglial cells around it. The axon is the cable-like projection that travels between the soma of a neuron and the dendrites of the next neuron. Axons contain microfilaments and microtubules, which are involved in vesicle traffic along the axon. Nerve impulses travel along axons between multiple neurons. Some neurons contain a myelin sheath, surrounding the axon. Myelin is made up of glial cells. Myelin increases the velocity of nerve impulse conduction.

4 Question No. 4 of 10 Which of the following statements about the portion of the synapse labeled in the image below is correct? A Question #04 A. The letter A points to small vesicles that store the neurotransmitter until it is released. B. The letter A points to vesicles in the post-synaptic cell. C. The neurotransmitter stored in these vesicles is produced elsewhere in the body and is delivered to these vesicles. D. The neurotransmitter contained in these vesicles crosses the synapse through channels. E. Neurotransmitter contained in vesicles can only be inhibitory in its action. A. Correct! Neurotransmitter vesicles are labeled in the image. The vesicles that are identified with the letter A in the image are in the pre-synaptic cells. The neuron produces and stores its own neurotransmitters. Once released from the vesicles, the neurotransmitter diffuses across the synaptic cleft. There are excitatory and inhibitory neurotransmitters. The synapse is the site of communication between neurons and other neurons or neurons and their target cells. The terminal boutons of one neuron synapse with another neuron to form a synaptic terminal. The synapse contains a gap where neurotransmitters cross, in order to transmit the neural signal.

5 Question No. 5 of 10 Which of the following statements is correct about the classification of neurons in the body? Question #05 A. When neurons are classified based on polarity, the neurons are divided into 6 categories. B. Afferent neurons deliver impulses from the peripheral nervous system to the central nervous system. C. Afferent neurons are also known as motor neurons. D. Sensory neurons function to modify the activity of a muscle or organ. E. There are 4 functional groups of neurons. When neurons are classified based on polarity, the neurons in the body are categorized into 3 main groups: A) unipolar, (B) bipolar and (C) multipolar. B. Correct! Afferent neurons deliver impulses from the peripheral nervous system to the central nervous system. Motor neurons are also known as efferent neurons. Motor neurons function to modify the activity of a muscle or organ. There are three functional groups of neurons: afferent, motor and interneuron. Neurons can be classified based on cell polarity. This classification includes: (A) unipolar, (B) bipolar and (C) multipolar. Examples of each include: (A) Unipolar - most of the body s sensory neurons, (B) Bipolar smell and taste neurons, and (C) Multipolar motor neurons and interneurons in the brain and spinal cord. Anaxonic neurons are special neurons that have no obvious dendrite or axon. They are found in the central nervous system and in special organs of sense, such as the nose. Neurons can also be classified based on function, such as the direction in which information is transmitted. The three functional groups are: (1) afferent neurons, (2) motor neurons, and (3) interneurons.

6 Question No. 6 of 10 Which type of neuron is labeled in the image below? Question #06 A A. Afferent neuron. B. Interneuron. C. Inhibitory afferent neuron. D. Excitatory afferent neuron. E. Motor neuron. Afferent neurons, such as a sensory neuron, have long axons that extend from the periphery into the central nervous system. B. Correct! The label in the image points to an interneuron. Afferent neurons are located outside of the central nervous system; the letter A in the image points to an interneuron. Afferent neurons are located outside of the central nervous system; the letter A in the image points to an interneuron. Motor neurons or efferent neurons extend from the central nervous system out to the periphery. Motor neurons (efferent neurons) transmit nerve impulses from the central nervous system to the periphery. Motor neurons modify the activity of an organ or muscle in the periphery. The peripheral nervous system has two efferent divisions the somatic nervous system and the autonomic nervous system.

7 Question No. 7 of 10 The neurons of the body are supported by the neuroglial cells. Which of the following statements about the neuroglial cells is correct? Question #07 A. In the central nervous system, neuroglial cells include Schwann cells. B. Neuroglial cells do not contribute to the repair of the nervous tissue. C. Ependymal cells line the ventricles of the brain. D. There are 4 neuroglial cell types in the peripheral nervous system. E. Oligodendrocyte projections onto the endothelial cells maintain the blood-brain barrier. Schwann cells are neuroglia of the peripheral nervous system. The repair of nervous tissue is facilitated by neuroglial cells. C. Correct! The ependymal cells do line the ventricles of the brain. The neuroglial cells of the peripheral nervous system are Schwann cells and satellite cells. Astrocyte projections maintain the blood-brain barrier. Glial cells provide the environment required for neurons to perform their functions. Glial cells myelinate neurons, regulate the nutrients and gases in the extracellular environment, and participate in the repair process. The glial cells found in the central nervous system are: ependymal cells, astrocytes, oligodendrocytes, and microglia. The peripheral nervous system has two types of glial cells: (1) Satellite cells and (2) Schwann cells. The peripheral nerves contain neuron cell bodies that are in the peripheral ganglia surrounded by the satellite cells.

8 Question No. 8 of 10 The human nervous system has some capacity to regenerate and restore normal functioning. Which of the following statements about nerve injury repair is correct? Question #08 A. The Schwann cell layer permits neuronal repair in the peripheral nervous system. B. In addition to Schwann cells, ependymal cells contribute to injury repair in the peripheral nervous system. C. Nerve injury leads to the proliferation of Schwann cells in the central nervous system. D. After a complete transection, all the axons will regrow and grow to re-form all the synapses. E. Oligodendrocytes in the peripheral nervous system grow along the axonal tract and help to reinnervate after an injury. A. Correct! The Schwann cell layer permits neuronal repair in the peripheral nervous system. Ependymal cells are part of the neuroglial cells in the central nervous system. Schwann cells are part of the peripheral nervous system neuroglia. After a transection, not all the axons will regrow and establish synapses. Oligodendrocytes are part of the neuroglia in the central nervous system; Schwann cells grow along the axonal tract and help to re-innervate after an injury.. Glial cells provide the environment required for neurons to perform their functions. Glial cells myelinate neurons, regulate the nutrients and gases in the extracellular environment, and participate in the repair process. The glial cells found in the central nervous system are: ependymal cells, astrocytes, oligodendrocytes, and microglia. The peripheral nervous system has two types of glial cells: (1) Satellite cells and (2) Schwann cells. The peripheral nerves contain neuron cell bodies that are in the peripheral ganglia surrounded by the satellite cells.

9 Question No. 9 of 10 A 44-year-old man is diagnosed with a disease that prevents the sodium channels in neurons from opening in response to an incoming action potential. Based on this information, which of the following is correct? Question #09 A. This disease would likely prevent the neuron from being pushed through the threshold and trigger an action potential. B. This disease would prevent the cell interior from being more negative on the inside. C. During the depolarizing phase, the membrane returns to the resting state. D. A larger stimulus leads to a stronger action potential. E. The disease this patient has would not prevent action potentials in the neurons in his nervous system because the influx of sodium into the cell is not required for depolarization. A. Correct! Without an increase in intracellular sodium, the cell could not depolarize and become more positive. This disease would prevent the cell interior from being more positive on the inside, which normally occurs during the generation of an action potential. During the depolarizing phase, the membrane potential changes to more positive. A larger stimulus does not lead to a larger action potential all or none principle. The influx of sodium is required to lead to depolarization of the cell membrane. An action potential is defined as a change in the membrane potential of an excitable cell, followed by a return to its resting membrane potential. When the excitable cell is stimulated, sodium permeable channels open up; this causes sodium to move through these channels due to the large concentration gradient and negative charge of the cytosol. This leads to the cell becoming depolarized (inside becomes less negative). If the potential is strong enough to surpass a preset threshold, an action potential is triggered. This potential is called the generator potential. The all-or-none principle states that larger currents do not produce larger action potentials. The action potential either occurs fully or not at all. In order for an action potential to occur, the stimulus must reach the threshold, which is the critical level of depolarization that must be crossed in order to trigger an action potential.

10 Question No. 10 of 10 An 81-year-old woman is diagnosed with poliomyelitis. The patient and her family are told by the physician the treatment plan for this disease. Based on this information, which of the following statements is correct? Question #10 A. Even though the patient was diagnosed with poliomyelitis, there is no risk of permanent damage to her nervous system. B. The infection this patient has could lead to permanent damage of her motor neurons. C. The polio virus specifically attacks the sensory neurons of the body, and the motor neurons are spared from damage. D. The polio outbreak prior to the 1950s stopped due to virus self-destruction of the virus. E. There are many drug options to cure poliomyelitis. Poliomyelitis can lead to permanent damage to motor neurons. B. Correct! The infection this patient has could lead to permanent damage of her motor neurons. The polio virus attacks motor neurons of the body and can lead to permanent changes in nervous system function. The vaccination campaigns against the polio virus helped to reduce the pandemic outbreaks that occurred prior to the 1950s. The modern treatment for poliomyelitis is still basically supportive. Poliomyelitis is an infection that can cause severe nervous system dysfunction in some individuals. The polio virus that infects and damages the nervous system was pandemic prior to the 1950s; since then, vaccination programs decreased the spread and incidence of this infection. The polio virus was easily spread from person to person and, in some cases, it would spread to the nervous system where it destroyed motor neurons. Modern treatment of affected individuals is still supportive therapy. Prevention through vaccination is the best method to ensure the infection rate is very low.