Nervous System Flashcards
Neurotransmitters
Chemical signal that allows nerve cells to communicate with each other
Sensory Input
Information gathered by sensory receptors.
Monitors internal and external changes.
Integration
Processing and interpretation of sensory input.
Motor Output
Activation of effector organs (muscles and glands).
Produces a response.
What is the CNS composed of? name the two functions
Composed of the brain and spinal cord located in the dorsal body cavity.
-Functions as the integration and control center.
-Interprets sensory input and dictates motor output.
Components of Peripheral Nervous System (2)
Spinal Nerves: Connected to and from the spinal cord.
Cranial Nerves: Connected to and from the brain.
Neurons
excitable cells that transmit electrical signals
Neuroglia (glial cells)
small cells that surround and wrap delicate neurons (helpers of neurons)
Afferent Nerves
carry signals from sensory receptors to the brain and spinal cord
Efferent Nerve
nerves that carry information away from the central nervous system, to the peripheral nervous system. ( motor output)
Autonomic Nervous System
regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal. Part of PNS.
What is the autonomic nervous system divided into?
the sympathetic division and the parasympathetic division
Sympathetic System
is best known for its role in responding to dangerous or stressful situations.
Adrenaline
kills your sense of pain and ups blood pressure
Parasympathetic Nervous System
responsible for the body’s rest and digestion response when the body is relaxed, resting, or feeding.
Somatic Nervous System
consists of nerves that go to the skin and muscles and is involved in conscious activities.
Dendrites
the receiving or input portions of a neuron
axon hillock
connects soma to axon
Axon Terminals
Distal endings of axon
Terminal Boutons
found at the end of the axon, below the myelin sheath, and are responsible for sending the signal on to other neurons.
Myelin sheath
Composed of myelin, a whitish, protein-lipid substance
Function of Myelin *2
Protect and electrically insulate axon
Increase speed of nerve impulse transmission
Myelinated Fibers Characteristics
Long and Fast
Non Myelinated Characteristics
Short and slow
Anterograde
movement away from cell body
Retrograde
movement toward cell body
Astrocytes (7)
-Support and brace neurons
-Play role in exchanges between capillaries and neurons
-Guide migration of young neurons
-Control chemical environment around neurons
-Respond to nerve impulses and neurotransmitters
I6.nfluence neuronal functioning
7. Participate in information processing in brain
Microglial Cells
- actually macrophage
- crawls along nervous system and eats bad stuff
Ependymal cells
- Produce CSF (cerbrospinal fluid)
- Form permeable barrier between cerebrospinal fluid (CSF) in cavities and tissue fluid bathing CNS cell
Oligodendrocytes
forms insulating myelin sheaths around CNS fibers
Schwann Cells
form myelin sheaths around ONLY one axon in PNS
Resting Membrane Potential
the electrical potential difference across the plasma membrane when the cell is in a non-excited state
What is the charge of the inside of a cell?
between -70 and -90 milivolts
Sodium Potassium Pump
In each cycle, three sodium ions exit the cell, while two potassium ions enter the cell. This allows the cell to build a concentration gradient and have a negative charge.
Depolarization
- decrease in membrane potential (moves toward zero and above)
- sodium channels are opened and sodium rushes inside the channel (charge becomes more positive)
- Inside of membrane becomes less negative than resting membrane potential
–Probability of producing impulse increases
Hyperpolarization
-Increase in membrane potential (away from zero)
- Inside of membrane becomes more negative than resting membrane potential
- Probability of producing impulse decreases
Thereshold
set charge that starts an action potential. depolarization occurs after.