1.
Neurons in the brain that make only local connections
Explanation
The correct answer is "interneurons." Interneurons are a type of neuron in the brain that make only local connections. They are responsible for relaying information between sensory and motor neurons, as well as coordinating communication between different regions of the brain. Unlike sensory and motor neurons, which transmit information to and from the central nervous system, interneurons only communicate within a specific area or circuit in the brain.
2.
_____________can alter activities in its target cells in muscles and glands.
Explanation
The nervous system is responsible for transmitting signals and messages to various parts of the body, including muscles and glands. It consists of the brain, spinal cord, and network of nerves that control and coordinate bodily functions. Through these signals, the nervous system can alter activities in its target cells, such as stimulating muscle contractions or regulating the secretion of hormones from glands. Therefore, the correct answer is the nervous system.
3.
The motor neuron is considered the
Correct Answer
A. Presynaptic cell
Explanation
A motor neuron is considered the presynaptic cell because it sends signals or action potentials to another neuron or muscle fiber, known as the postsynaptic cell, through a synapse. The presynaptic cell releases neurotransmitters into the synapse, which then bind to receptors on the postsynaptic cell, allowing for the transmission of the signal.
4.
the skeletal muscle is the
Correct Answer
B. Postsynaptic cell
Explanation
The skeletal muscle is the postsynaptic cell because it receives signals from the presynaptic cell, which is usually a motor neuron. The presynaptic cell releases neurotransmitters that bind to receptors on the postsynaptic cell, causing a response in the skeletal muscle. This response can involve muscle contraction or relaxation, allowing for movement and control of the body.
5.
Sodium potassium pump
Correct Answer
B. Sodium ions out of the cell, potassium ions into the cell
Explanation
The sodium-potassium pump is responsible for maintaining the electrochemical gradient across the cell membrane. It actively transports sodium ions out of the cell and potassium ions into the cell. This process requires energy in the form of ATP. By pumping three sodium ions out for every two potassium ions pumped in, the pump helps to create a negative charge inside the cell and a positive charge outside, which is crucial for various cellular processes such as nerve impulse transmission and muscle contraction.
6.
________motor neuron exhibit a resting potential that is more negative than the "threshold" potential
Correct Answer
resting
Explanation
Motor neurons exhibit a resting potential that is more negative than the "threshold" potential because the resting potential is the electrical charge across the neuron's membrane when it is not transmitting signals. This resting potential is maintained by the uneven distribution of ions inside and outside the neuron, with more negative ions inside the neuron. The threshold potential, on the other hand, is the minimum level of depolarization required to generate an action potential and transmit a signal. Therefore, the resting potential needs to be more negative than the threshold potential to ensure that the neuron remains at rest and does not transmit signals unless a strong enough stimulus is received.
7.
Action potential moves along axons more rapidly in non-myelinated than in myelinated axons.
Correct Answer
B. False
Explanation
Action potential moves along axons more rapidly in myelinated than in non-myelinated axons.
8.
The opening of voltage-gated sodium channels
Correct Answer
Action potential
9.
The observation that the acetylcholine release into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it is called a _____________sodium channel.
Correct Answer
ligand gated
ligand-gated
Explanation
The correct answer is "ligand-gated." This term refers to the observation that acetylcholine, a ligand, binds to a sodium channel and opens it. This mechanism allows for the transmission of signals from motor neurons to skeletal muscles.
10.
Major inhibitory neurotransmitter of the human brain
Correct Answer
GABA
gaba
Explanation
GABA (gamma-aminobutyric acid) is the major inhibitory neurotransmitter of the human brain. It functions by reducing the activity of neurons, preventing them from firing and transmitting signals. GABA plays a crucial role in regulating brain activity, maintaining a balance between excitatory and inhibitory signals. Its inhibitory effects help to control anxiety, promote relaxation, and regulate sleep. GABA is widely distributed throughout the brain and is involved in various physiological and neurological processes.
11.
The botulinum toxin reduces the synaptic release of
Correct Answer
acetylcholine
Explanation
Botulinum toxin is known to inhibit the release of acetylcholine, a neurotransmitter responsible for transmitting signals between nerve cells. By reducing the synaptic release of acetylcholine, the toxin interferes with the communication between nerves and muscles, leading to muscle paralysis. This mechanism is utilized in medical treatments such as Botox injections to temporarily relax muscles and reduce the appearance of wrinkles.