High School Biology : Nervous Tissue

Study concepts, example questions & explanations for High School Biology

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Example Questions

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Example Question #1 : Nervous Tissue

What support cell is responsible for myelinating the axons found in the peripheral nervous system?

Possible Answers:

Schwann cells

Oligodendrocytes

Ependymal cells

Astrocytes

Correct answer:

Schwann cells

Explanation:

There are two types of cells responsible for myelinating axons in the nervous system: oligodendrocytes and Schwann cells. They only differ by the division of the nervous system in which they are found. Oligodendrocytes myelinate axons in the central nervous system, while Schwann cells myelinate axons in the peripheral nervous system.

Ependymal cells and astrocytes are other types of neuroglia. Ependymal cells secrete cerebrospinal fluid (CSF) into the central nervous system. Astrocytes play a key role in creating the blood-brain barrier in the central nervous system.

Example Question #2 : Nervous Tissue

Which of these is not a part of the cerebrum?

Possible Answers:

The hippocampus

The thalamus

The occipital lobe

The primary sensory cortex

Broca's area

Correct answer:

The thalamus

Explanation:

The cerebrum is the portion of the brain above the middle of the brain, or diencephalon. The thalamus is a part of the diencephalon, and it is intimately associated with motor behaviors, such as walking or flying (in birds). The cerebrum is divides into four lobes based on location and function. The frontal lobe contains the motor cortex and pre-frontal cortex, as well as Broca's area. It is associated with thought and higher brain function. The parietal lobe contains the sensory cortex and processes tactile input. The temporal lobe contains the hippocampus and auditory cortex. The occipital lobe contains the visual cortex.

Example Question #1 : Nervous Tissue

What type of nervous cell is used to phagocytose pathogens and debris in the central nervous system?

Possible Answers:

Schwann cells

Microglia

Astrocytes

Oligodendrocytes

Correct answer:

Microglia

Explanation:

Nervous tissue contains a variety of support cells in order to preserve the neurons in the brain, known as glial cells. Microglia are similar to monocytes, a type of white blood cell. They are used to remove debris and pathogens from the central nervous system.

Schwann cells, oligodendrocytes, and astrocytes are all part of the neural glia. Schwann cells produce myelin around the axons of neurons in the peripheral nervous system, while oligodendrocytes produce myelin for the axons of neurons in the central nervous system. Astrocytes around found in the central nervous system and help create the blood-brain barrier.

Example Question #4 : Nervous Tissue

Which of the following types of tissue is not an element in the neuron-to-muscle pathway?

Possible Answers:

Motor neurons

Association neurons

Effectors

Sensory neurons

Connective neurons

Correct answer:

Connective neurons

Explanation:

Sensory neurons respond to stimuli, such as pain. Association neurons receive signals from the sensory neurons and, on the basis of that input, activate motor neurons. Motor neurons activate muscles or glands. Effectors are the muscles or glands that perform the response directed by the nervous system.

Connective tissue consists of bone, cartilage, blood, and fat and is not involved in this process. Connective neurons is a misnomer. Interneurons, however, can be used to relay signals between sensory and motor neurons in the spinal cord.

Example Question #5 : Nervous Tissue

What part of a neuron is considered white matter?

Possible Answers:

Synapse

Dendrite

Cell body

Axon

Synaptic bud

Correct answer:

Axon

Explanation:

White matter is white due to the myelin sheath. Since the myelin sheath only covers the axon, neural tissue that is referred to as white matter is only located on a neuron's axon. Grey matter actually refers to the cell body due to its grayish appearance. Accordingly, one neuron is actually part of both the white and the gray matter in the nervous system.

Example Question #1 : Understanding Properties Of Nervous Tissue

Which of the following occurs in synaptic transmission?

Possible Answers:

Neurotransmitter chemicals diffuse across the synaptic cleft

Only a small potential is generated in the post-synaptic neuron

All of these events occur during synaptic transmission

The action potential depolarizes the end of the pre-synaptic neuron

The membranes of synaptic vesicles fuse with the cell membrane of the pre-synaptic neuron

Correct answer:

All of these events occur during synaptic transmission

Explanation:

As the action potential depolarizes the pre-synaptic terminal button, calcium enters the region and causes the vesicles (full of neurotransmitter) to fuse their membranes with the membrane of the neuron, leading to rapid release of their chemical content outside of the cell. The neurotransmitters must diffuse across the synaptic cleft in order to cause a post-synaptic effect. Typically, many, many excitatory inputs must summate to cause depolarization of the post-synaptic neuron. Each individual stimulus is generally well below threshold, and the post-synaptic neuron will only generate an action potential with several stimuli at once.

Example Question #2 : Nervous Tissue

When an action potential reaches the axon of a neuron, what is the first event to occur?

Possible Answers:

Extracellular sodium rushes into the cytoplasm

Calcium rushes into the cytoplasm

Extracellular potassium rushes into the cytoplasm

Intracellular potassium rushes out of the cytoplasm

Intracellular sodium rushes out of the cytoplasm

Correct answer:

Extracellular sodium rushes into the cytoplasm

Explanation:

At rest, the neuron will have large amounts of sodium outside the cell and large amounts of potassium inside the cell. When an action potential reaches the axon of the neuron, it opens voltage-gated sodium channels. Sodium immediately rushes through these channels to enter the cell, flowing from high sodium concentration to low sodium concentration. This event is known as depolarization.

Later in the action potential, potassium channels will open and potassium will rush out of the cell along its concentration gradient. This is part of the action potential leads to hyperpolarization.

Example Question #3 : Nervous Tissue

What is the purpose of the nodes of Ranvier?

Possible Answers:

They allow a way from neurons to communicate with each other, via connecting nodes

They provide support and protection to the axon

They allow neurons to recieve oxygen

They allow the transport of proteins along the axon

They allow the action potential to skip over sections of the axon

Correct answer:

They allow the action potential to skip over sections of the axon

Explanation:

A fatty substance called myelin wraps arounds the axon of a neuron, forming an insulating layer called the myelin sheath. Gaps in the myelin coating create small openings, called the nodes of Ranvier, where the cell membrane is exposed. During an action potential, the electrical signal is able to jump from on node to the next, skipping portions of the axon. This speeds up the conduction of the action potential signal. Instead of travelling in a constant wave down the axon, the signal can jump or bounce past segments of it. This process is known as saltatory conduction.

Many neurological diseases and disorders arise from the degeneration of the myelin sheath, slowing the propagation of action potentials and hindering neural functionality.

Example Question #971 : High School Biology

What do function do glial cells facilitate?

Possible Answers:

They produce neural impulses

They amplify neural impulses

They increase the speed of nerve impulses

They send and receive nerve impulses

They detect malfunctioning nerve impulses

Correct answer:

They increase the speed of nerve impulses

Explanation:

Glial cells are cells that make up nervous tissue and provide support, protection, and nutrients for the neurons in the brain and nervous system. While neurons are the cells responsible for actually generating, sending, and receiving neural impulses, glial cells are capable of enhancing the speed at which these impulses can be transmitted. In particular, Schwann cells and oligodendrocytes provide myelin sheaths to neurons. Myelin acts as an insulator and helps the action potential travel more quickly down the neural axon.

Example Question #1 : Nervous Tissue

Into what structure does a neuron release neurotransmitters?

Possible Answers:

Axon

Dendrite

Synaptic cleft

Nodes of Ranvier 

Soma

Correct answer:

Synaptic cleft

Explanation:

Neurotransmitters are released from the axon terminal into the synaptic cleft.

Neurons are essential for transmitting signals, but do so without actually touching one another. The space between neurons is known as the synaptic cleft, or synapse. When a signal reaches the end of one neuron at the axon terminal, it causes neurotransmitters to be released from vesicles. The neurotransmitter molecules travel to the dendrites of the next neuron, which receives the signal and passes it down the next axon.

The soma is the cell body of the neuron, which synthesizes proteins and integrates incoming signals. Nodes of Ranvier are regions along myelinated axons that allow for faster action potential conduction.

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