Nerve Tissues Flashcards
What are the two main types of nerve tissue?
Neurons and glial cells
What is an axon?
The axon is a threadlike extension of a neuron that carries electrical impulses known as action potentials away from the nerve cell body to be received by other neurons.
What is a dendrite?
Dendrites are located on the end of a neuron. Dendrites are responsible for making synaptic connections and receive signals from axons.
What is a cell body?
A cell body (soma) is the core section of the neuron. The cell body contains the nucleus which gets signals from different neurons by using its dendrites. The cell body contains genetic information, maintains the structure, and provides energy to drive neural activity.
What is the structure of a sensory neuron?
A sensory neurons have long dendrites and short axons.
What is the structure of an interneuron?
Interneurons have short dendrites and short axons.
What is the structure of a motor neuron?
A motor neuron has short dendrites and long axons.
What is the general function of a sensory neuron?
Sensory neurons get information about what’s going on inside and outside of the body and bring that information into the CNS so it can be processed. Sensory neurons are activated by sensory input from the environment.
What is the general function of an interneuron?
Interneurons, which are found only in the CNS, connect one neuron to another. They receive information from other neurons (either sensory neurons or interneurons) and transmit information to other neurons (either motor neurons or interneurons).
What is the general function of a motor neuron?
Motor neurons get information from other neurons and convey commands to your muscles, organs and glands referred to as effectors (effectors are muscles that respond to nerve impulses). Stimulation from the electrical impulse of an effector will produce a response such as muscle contraction or hormonal release.
What is a synapse?
A synapse is a small gap at the end of a neuron that allows neurons to transmit information. Synapses are found where neurons connect with other neurons. Impulses pass through the diffusion of neurotransmitters.
What is myelin sheath?
Myelin is an insulating layer, or sheath that forms around the axon and protects it from foreign electrical impulses. This myelin sheath allows electrical impulses to transmit quickly and in trade the speed at which neurons convey their message.
What are nodes of Ranvier?
The node are the gaps formed between the myelin sheath where the axons are left uncovered. The nodes of Ranvier allow for ions to diffuse in and out of the neuron, and propagate the electrical signal down the axon.
What are Schwann cells?
Schwann cells are cells in the peripheral nervous system that form the myelin sheath around a neuron’s axon. They are a type of glial cell that surrounds neurons, keeping them alive.
What is the peripheral nervous system? (PNS)
The peripheral nervous system (PNS), consists of the parts outside the brain and spinal cord and is composed of nerves that are responsible for carrying signals between the CNS and the rest of the body.
What is the central nervous system? (CNS)
The central nervous system (CNS) consists of the brain and the spinal cord. Analyzation of information takes place in the CNS.
What is a neuron?
Neurons are the basic functional units of the nervous system, and they generate electrical signals called action potentials, which allow them to quickly transmit information over long distances.
What is a glial cell?
Glial cells are essential to nervous system function, but they work mostly by supporting the neurons. They are the most abundant type of cell in the CNS.
How does the motion of sensory neurons and motor neurons relate to the CNS?
A sensory neuron carries impulses from the receptor to the CNS (brain or spinal cord), while a motor neuron carries impulses from the CNS (brain or spinal cord) to the effector.
What is the axon terminal?
An axon terminal contains many vesicles filled with neurotransmitters which allows the neuron to conduct electrical impulse down to another neuron or another type of cell by the release of signals into the synapse.
What is a synaptic cleft?
The synaptic cleft is the space where nerve impulses are transmitted by neurotransmitters.
What is a neurotransmitter?
A neurotransmitter is a chemical substance/molecule which is released from the axon terminal from the arrival of a nerve impulse. Neurotransmitters diffuse across the synapse to transmit the message.
What are the function of vesicles?
The vesicle is a small sac that contains neurotransmitters enclosed by a lipid bilayer. Synaptic vesicles in the presynaptic membrane store neurotransmitters that are used to communicate across the synaptic cleft
What is an axon hillock?
The axon hillock is the region of a neuron that controls the initiation of an electrical impulse based on the inputs from other neurons or the environment
What is an action potential?
Action potentials (electrical impulses) are the a temporary shift (from negative to positive) in the neuron’s membrane potential caused by ions diffusing in and out of the neuron.
What is a presynaptic neuron?
The presynaptic neuron is the neuron conducting impulses towards the synapse and transmitting messages to the synaptic cleft by releasing neurotransmitters from the axon terminal of a presynaptic neuron.
What is a postsynaptic neuron?
The postsynaptic neuron is the neuron transmitting the electrical signal away from the synapse. The dendrite of a postsynaptic neuron receives the neurotransmitter.
What is the difference between the synapse and the synaptic cleft?
The synaptic cleft is the small gap between the presynaptic neuron terminal and the postsynaptic neuron terminal. The synapse is the whole structure.
What is an overview of the synapse and synaptic cleft?
A synapse is a small area between two neurons where nerve impulses are transferred from axons of a presynaptic (sending) neuron to a dendrite of a postsynaptic (receiving) neuron through a neurotransmitter. It is termed the synaptic gap or synaptic cleft. A space between two neurons is a synaptic gap (synaptic cleft).
What is synaptic transmission? (Simple)
Neurotransmission is the process by which signaling neurotransmitters are released by the axon terminal of a presynaptic neuron, and bind to and react with the receptors on the dendrites a postsynaptic neuron across the synaptic cleft.
What is synaptic transmission? (detailed)
When the presynaptic neuron is excited by an action potential, the vesicles fuse with the presynaptic membrane and release the neurotransmitters into the synaptic cleft (exocytosis). In the synaptic cleft, neurotransmitters interact with receptors on the postsynaptic membrane. They bind to the receptors and can cause an action to occur in the postsynaptic neuron that can increase or decrease the activity of the cell.
What is saltatory conduction?
Saltatory conduction is the propagation of the action potential along myelinated axons from one node of Ranvier to the next, increasing the conduction velocity of the action potential
What role does calcium and contractile proteins play in synaptic transmission?
Calcium ions cause contractile proteins to pull synaptic vesicles to the presynaptic membrane. Vesicle fuses with presynaptic membrane, releasing neurotransmitters into synapse. (EXOCTYOSIS)
Why are neurotransmitters deactivated?
Neurotransmitters are quickly deactivated to prevent them from continually acting on postsynaptic membrane and for continuous stimulation or inhibition of postsynaptic membrane.
What is reuptake?
Synaptic ending reabsorbs the neurotransmitter for repackaging by synaptic vesicle or for molecular breakdown
What is enzyme degradation?
Degradation breaks down the neurotransmitter molecule by enzyme activity. Neurotransmitters can be degraded by enzymes in the synapse.
What happens in the postsynaptic neuron?
Neurotransmitters DIFFUSE across synaptic cleft to receptors on postsynaptic membrane. The receptors control selective ion channels; binding of a neurotransmitter to its specific receptors opens the ion channels. The resulting ion flux changes the voltage of the postsynaptic membrane. The neurotransmitters binding to receptors on the dendrite causes the nerve impulse to be transmitted down the dendrite of the postsynaptic neuron.
