Neuro pt1 Flashcards
What is the Central Nervous System (CNS)?
The CNS consists of the brain and spinal cord.
What is the Peripheral Nervous System (PNS)?
The PNS includes spinal and cranial nerves. (input/output)
What is the Sensory (Afferent) Division?
The Sensory Division transmits signals TO the CNS.
What are somatic afferents?
Somatic afferents (input) are sensory signals from skin, muscle, and joints.
What are visceral afferents?
Visceral afferents are sensory signals from membranes and organs.
What is the Motor (Efferent) Division?
The Motor Division transmits signals FROM the CNS.
What is the Somatic Nervous System?
The Somatic Nervous System is voluntary and sends signals to skeletal muscles.
What is the Autonomic Nervous System?
The Autonomic Nervous System is involuntary and sends signals to organs and glands.
What are the two divisions of the Autonomic Nervous System?
The two divisions are the Sympathetic Division and the Parasympathetic Division.
What is a neuron?
A neuron is a special cell of the nervous system that carries messages in the form of electrical impulses.
What are supporting cells of neurons?
Supporting cells assist neurons in their functions. (glial)
astrocytes,microglia,ependymal cells, oligodendrocytes
What are glial cells?
Glial cells are support cells of the CNS.
What do astrocytes do?
Astrocytes regulate the environment around neurons and transport substances from capillaries.
What is the function of microglia?
Microglia eat infectious microbes in the CNS.
What do ependymal cells do?
Ependymal cells line the cavities of the brain and spinal cord and flush cerebrospinal fluid (CSF).
What is the role of oligodendrocytes?
Oligodendrocytes form myelin sheaths around axons in the CNS, increasing the speed of impulses.
What do Schwann cells do?
Schwann cells form myelin sheaths around axons in the PNS and assist in axon regeneration.
What are satellite cells?
Satellite cells control the chemical environment in the PNS.
What are the special characteristics of neurons?
Neurons are amitotic, have longevity, and a high metabolic rate.
What does amitotic mean?
Amitotic means that neurons cannot reproduce or regenerate after a certain point in life.
What is the neuron cell body?
The neuron cell body (soma) is the major part from which processes (axon and dendrites) project.
What are Nissl Bodies?
Nissl Bodies are rough endoplasmic reticulum that make proteins and plasma membrane.
What is a nucleus in the CNS?
A nucleus is a collection of cell bodies in the CNS.
What is a ganglion in the PNS?
A ganglion is a collection of cell bodies in the PNS.
What are dendrites?
Dendrites are branching, rootlike extensions off the cell body that receive signals.
What is an axon?
An axon is an extension that carries an all-or-nothing action potential from the cell body to the target.
What is a tract?
A tract is a bundle of axons in the CNS.
What is a nerve?
A nerve is a bundle of axons in the PNS.
What is the axolemma?
The axolemma is the plasma membrane of the axon.
What is the axon hillock?
The axon hillock is the cone-shaped region where the axon attaches to the cell body and where action potentials are triggered.
What are axon collaterals?
Axon collaterals are rare branches of an axon.
What are telodendria?
Telodendria are (typical) terminal branches of an axon that may number up to 15,000.
What are synaptic knobs?
Synaptic knobs are at the end of each telodendrion and secrete neurotransmitters.
What is the myelin sheath?
The myelin sheath is a wrap of Schwann cells and oligodendrocytes around the axon.
What are nodes of Ranvier?
Nodes of Ranvier are gaps between myelin cells at regular intervals on the axon.
What is white matter of the brain?
White matter consists of areas with myelinated axons.
What is gray matter of the brain?
Gray matter consists of areas with cell bodies and unmyelinated cell processes.
What is a multipolar neuron?
A multipolar neuron has three or more cell processes (projections), typically many dendrites and one axon.
What is a bipolar neuron?
A bipolar neuron has two processes: one dendrite and one axon extending from opposite sides of the cell body.
What is a unipolar neuron?
A unipolar neuron has one long process attached to the cell body by a ‘T’ like extension.
What is a sensory (afferent) neuron?
A sensory neuron transmits impulses from sensory receptors TOWARD the CNS.
What is a motor (efferent) neuron?
A motor neuron transmits impulses AWAY FROM the CNS to target tissue.
What is an association neuron (interneuron)?
An association neuron connects sensory and motor neurons. (is done within CNS)
What is voltage?
Voltage is the measure of potential energy resulting from the separation of positive and negative charges.
What are volts?
Volts are the units of voltage, with millivolt (mV) being a typical unit used for membrane voltages.
What is current?
Current is the flow of electrical charges from one area to another, typically the flow of ions.
What is resistance?
Resistance is the hindrance to the flow of charge through which current must pass.
What is Ohm’s Law?
Ohm’s Law states that current (I) equals voltage (V) divided by resistance (R).
What happens when voltage increases?
Increased voltage results in increased current.
What are leakage channels?
Leakage channels are channels that are always open.
What are chemical-gated channels?
Chemical-gated (LIGAND) channels open or close when bound by a specific molecule.
What are voltage-gated channels?
Voltage-gated channels open or close depending on the voltage across the membrane.
What is an electrochemical gradient?
The electrochemical gradient is the net result of both the electrical and chemical gradients.
