A&p Nervous System Part 1

Myelin is the material that insulates a neuron. It is a fatty substance that forms a protective layer around the axon of a neuron, allowing for faster and more efficient transmission of electrical impulses. This insulation helps to prevent the loss of electrical signals and allows for quicker communication between neurons.

The central nervous system is made up of the brain and spinal cord. The brain is responsible for processing information, controlling body functions, and coordinating movement. The spinal cord acts as a pathway for nerve signals between the brain and the rest of the body. Together, the brain and spinal cord form the central command center for the body's nervous system, allowing for the integration and coordination of sensory information and motor responses.

The correct answer includes the shapes of neurons: Bipolar, Unipolar, and Multipolar. These are the three main types of neuron shapes found in the nervous system. Bipolar neurons have two processes extending from the cell body, while unipolar neurons have a single process and multipolar neurons have multiple processes. These different shapes allow neurons to perform different functions and transmit information throughout the body.

In myelinated neurons, the depolarization "jumps" from one node of Ranvier to the next. This is known as saltatory conduction and it allows for faster transmission of the electrical signal along the axon. The myelin sheath acts as an insulator, preventing the dissipation of the electrical signal and forcing it to "jump" from one node to another, which speeds up the transmission process.

Neurotransmitters have the ability to open sodium ion channels in the cell body. This means that when a neurotransmitter binds to a receptor on the cell body, it causes the sodium ion channels to open, allowing sodium ions to enter the cell. This influx of sodium ions can lead to the generation of an action potential and the transmission of signals between neurons. Therefore, the statement "Neurotransmitters open sodium ion channels in the cell body" is true.

The peripheral nervous system consists of the cranial nerves and spinal nerves. These nerves are responsible for transmitting signals between the central nervous system (brain and spinal cord) and the rest of the body. The cranial nerves originate from the brain and control functions like vision, hearing, and taste. The spinal nerves originate from the spinal cord and control functions like movement and sensation in the limbs and trunk. So, the correct answer is cranial nerves and spinal nerves.

Saltatory conduction refers to the process of the depolarization "jumping" from one node of Ranvier to the next in myelinated neurons. This occurs because the myelin sheath insulates the axon, preventing the flow of ions through the membrane. Instead, the depolarization occurs only at the nodes of Ranvier, where the myelin sheath is absent. This allows for faster and more efficient conduction of the electrical signal along the axon.

When a neuron reaches threshold potential, the first channels to open up in sequence are the voltage-gated sodium channels. These channels allow sodium ions to flow into the neuron, causing depolarization and the generation of an action potential. The opening of voltage-gated sodium channels is the initial step in the process of transmitting an electrical signal along the neuron.

Resting potential refers to the electrical charge inside a normal, inactive neuron. It is the state of the neuron when it is not sending any signals. The resting potential is characterized by the inside of the neuron being more negative than the outside. Once the threshold is reached, the neuron will send a signal, but this is not a definition of resting potential. Therefore, the correct answer is the exact electrical charge inside of a normal, inactive neuron.

Astrocytes create a blood-brain barrier, as the bloodstream never directly contacts neurons. The blood-brain barrier is a protective mechanism that separates the blood vessels in the brain from the surrounding brain tissue. It is formed by a layer of specialized cells called astrocytes, which tightly regulate the movement of substances between the bloodstream and the brain. This barrier prevents harmful substances and pathogens from entering the brain, while allowing essential nutrients, oxygen, and hormones to pass through and be transported to neurons.

After an action potential, the cell membrane needs to reset its charge. This is achieved by opening potassium gates. These gates allow the flow of potassium ions out of the cell, which helps to restore the negative charge inside the cell and bring it back to its resting state. Sodium gates are involved in the generation of an action potential, not in resetting the charge. The potassium pump is responsible for maintaining the concentration gradient of potassium ions across the cell membrane, but it is not directly involved in resetting the charge after an action potential.

Myelin is a fatty insulating sheath that surrounds and protects the axons of many neurons in the nervous system. This myelin sheath acts as an insulator, which helps to speed up the transmission of electrical signals along the axon.

When neurotransmitters are released and interact with target neurons, they bind to chem-gated sodium channels. This binding causes these channels to open, allowing sodium ions to flow into the neuron and generate an action potential. Voltage-gated sodium channels are responsible for propagating the action potential along the neuron, but they are not directly involved in the initial opening of the channels in response to neurotransmitter binding.

After neurotransmitters open up to a sodium pump, they are reabsorbed. This means that they are taken back up into the presynaptic neuron from the synaptic cleft. Reabsorption is an important process in the regulation of neurotransmitter levels and helps to terminate the signal transmission between neurons.

The nervous system performs three main functions: sensation, integration, and response. Sensation refers to the process of detecting and receiving information from the environment through sensory receptors. Integration involves the interpretation and processing of this sensory input in the brain and spinal cord. Finally, response refers to the generation of appropriate motor output or actions in response to the sensory input and integration. Sensory input is not a function of the nervous system, but rather a component of the sensation function.