Chapt. 2 Flashcards
What are the two cells that make up the human nervous system?
- Neurons
* Glia
What are the major components of neurons?
- dendrites
- soma (cell body)
- axon
- presynaptic terminals
Tell me about the cell body (soma).
- contains the nucleus, mitochondria, ribosomes, and other structures
- responsible for the metabolic work of the neuron
Tell me about the membrane.
- it’s a structure that separates the inside of the cell from the outside environment
- protects, or shields, the cell
Tell me about the nucleus.
- it’s a structure that contains the chromosomes
Tell me about dem motherfucking mitochondria.
- it’s a structure that performs metabolic activates and provides energy that the cell requires
Tell me about ribosomes.
- where the cell synthesizes new protein molecules
Tell me about the endoplasmic reticulum.
- it’s a network of thin tubes that transport newly synthesized proteins to their location
Tell me about dendrites.
- they are the branching fibers at the end of a neuron that are lined with synaptic receptors responsible for bringing info into the neuron
Tell me about the axon.
- it’s a thin fiber of a neuron responsible for transmitting nerve impulses toward other neurons, organs, or muscles
Tell me about the presynaptic terminals.
- the end points of an axon where the release of chemicals to communicate with other neurons occurs
Different types of neurons?
- motor
- sensory
- inter
Afferent axon…
bring info INTO a structure
Efferent axon…
carrying info AWAY from a structure
Name the different types of Glia in the brain
- astrocytes
- microglia
- oligodendrocytes
- Shwann cells
- Radial glia
Astrocytes are..
a type of glia that help to synchronize the activity of the axon by wrapping around the presynaptic terminal and taking up chemicals released by the axon
Microglia are…
a type of glia that remove waste material and other microorganisms that could prove harmful to the neuron
Oligodendrocytes are..
these are located in the brain and spinal cord and they build the myelin sheath that surrounds and insulates certain vertebrate axons
Shwann cells are
these are located in the periphery of the body and they also build the myelin sheath that surrounds and insulates certain vertebrate axons
Radial glia are..
a type of glia that guide the migration of neurons and the growth of their axons and dendrites during embryonic development
What is the Blood-Brain Barrier?
a mechanism that surrounds the brain and blocks most chemicals from entering
What is active transport?
the protein-mediated process that expends energy to pump chemicals from the blood into the brain
What are are some things active transport brings into the brain?
glucose, certain hormones, amino acids, a few types of vitamins
What is glucose?
a sugar that is one of the few nutrients that CAN pass through the blood brain barrier
What do vertebrate neurons depend almost entirely on for nourishment?
GLUCOSE!
What is a nerve impulse?
an electrical message that is transmitted down the axon of a neuron
What is resting potential?
the state of the neuron prior to the sending of an impulse
What is polarization?
a difference in the electrical charge of two locations ( a difference in the electrical charge inside/outside of a cell)
The membrane is selectively permeable. What does this mean?
it means it allows some chemicals to pass more freely than others (hence SELECTIVE)
What is depolarization?
a decreasing of polarization towards 0
What is happening to sodium and potassium when the membrane is at rest?
- sodium channels are closed
- potassium channels are slightly closed, allowing for a slow passage of potassium
What is action potential?
a rapid depolarization of the neuron (this occurs when their is a stimulation of the neuron past the action potential’s threshold of excitation)
What is hyperpolarization?
increasing the polarization or the difference between the electrical charge of two places
What do Voltage-Activated Channels do?
these are membrane channels whose permeability depend upon the voltage difference across the membrane
The All-or-None Law states that..
the amplitude and velocity of an action potential are independent of the intensity of the stimulus that initiated it
Action potentials vary from one neuron to another in terms of…
- amplitude
- velocity
- shape
What happens during a refractory period?
at this time the neuron resists the production of another action potential (this happens after an action potential)
What are the two types of refractory periods?
Absolute (happens first and cannot produce an action potential) and Relative (happens second and it takes a stronger than usual stimulus to trigger action potential)
What is the axon hillock?
swelling where the axon exits the soma (cell body)
What are the short, unmyelinated interrupted sections in the myelin sheath of axons?
Nodes of Ranvier
What is Saltatory Conduction?
a term used to describe the “jumping” of the action potential from node to node (provides fast conduction of impulses and conserves energy for the cell)
Local neurons have..
short axons that exchange info with only close neighbors and do NOT produce action potentials
When local neurons are stimulated they produce..
graded potentials which are membrane potentials that vary in magnitude and do NOT follow the all-or-none law
