Chapter 13 Nervous System Flashcards
Review the structure of a neuron and the direction of information flow: cell body, dendrite, and axon.
Cell body- rounded mass that contains the nucleus and organelles
Dendrites- many little “branches” from cell body, receives input
Axons- longer stem, few, sends information away from the cell
What is a presynaptic neuron? Postsynaptic neuron?
Pre-synaptic- Sender
Post-synaptic- after synapse, the receiver
What is the job of a neurotransmitter and what is a synapse?
Synapse: small space between communicating neurons
Neurotransmitter: Communication molecules that convey neural information as positive or negative
How does a myelin sheath affect the rate of impulse travel?
It increases the speed of impulse
Explain the autoimmune disease multiple sclerosis.
Myelination is damaged- Causes signal to be slower, also can form scarring that can inter-rupt axon communication
Results in scarring
Nerve impulse transmission is slowed or interrupted
Signs- clumsiness, lack of coordination.
A progressive disease that just gets worse
At rest, the inside of the neuron is more negative as compared to the fluid on the out-side of the neuron. Why?
Because there are 3 Positive sodium ions on the OUTSIDE and only 2 POSITIVE ions on the INSIDE.
The action threshold is reached as the inside of the neuron becomes less negative. When the inside of the cell reaches -55mV and an action potential is generated. Be able to describe the three steps of the action potential (Depolarization, Repolarization, Re-turn to Resting State).
Resting potential- Na/K pump working (channels blocked off)
Depolarization- Sodium channel opens and sodium rushed INSIDE making outside and inside more similar causing a FIRE
Repolarization- K+ channel opens and Potassium rushes out making inside more negative
Resting Potential- Na/K pump only back to normal (channels blocked off)
How does the impulse (wave of action potentials) generated by the first action potential move down the axon?
An action potential in one region of the axon stimulates the adjacent region
Starts a wave of action potentials down the axon (an impulse)
Opens this channel, then this channel, then this channel Wave (Na, P, Na, P)
Unidirectional propagation of wave
How does an inhibitory neurotransmitter affect the postsynaptic neuron? How does an excitatory neurotransmitter affect the postsynaptic neuron?
An inhibitory neurotransmitter allows more negative stuff to come inside the cell making it less likely to fire (hyperpolarization)
An Excitatory neurotransmitter contains glutamate, a chemical that promotes firing.
What are the two main divisions of the nervous system? Name the general structures and functions of each division.
Central Nervous System (CNS)
Contains the brain and spinal cord
Function- Integrating and command center (The Boss, decision maker)
Peripheral Nervous System (PNS)
Mostly made up of the nerves that extend from the CNS
Function- Links sensory nerves to the appropriate organs (Brings in the info to actually do it)
There are three major types of neurons of the nervous system (sensory neurons, inter-neurons and motor neurons). Which carries information from the peripheral nervous system to the central nervous system? Which carries information from the central nervous system to the peripheral nervous system to organs, glands etc…and which carries information within the central nervous system?
The 3 kinds of nerves in the CNS and PNS are
Sensory neurons- Carries information from PNS to CNS
Interneurons- carries information within the central nervous system
Motor Neurons- Carries information from CNS to PNS to organs
Name the 3 major regions of the brain. Name the general functions of each. Realize the brain is much more complicated!
Forebrain- cerebrum. Where your complex behavior come from ,emotions.
Frontal lobe doesn’t develop until age 25, This is what stops you from doing things your impulses tell you to do.
Midbrain- Coordination of muscle groups, sight and sound
Hindbrain- Breathing, heart rate. Coordinates basic muscle movement and automatic vital functions
Cerebellum- helps muscle memory. Also remembers coordinated muscle movements
Explain how the following protect and/or support the central nervous system: bones, meninges and cerebrospinal fluid, blood-brain barrier.
Bone Skull
Meninges (3 layers, rough on outside, get softer on inside) Inside of them you make fluid. Hold fluid around brain CSF (Cerebrospinal Fluid)
Suspends your brain in fluid
Blood Brain Barrier Tight barium that completely surround capillaries. Prevents pathogens from getting into the brain
What is memory? How
Memory is stored information that can be retrieved later.
In order to turn short term memories into long term memories you must use rep-etition, this helps create a familiar fire pattern.
Describe the cause and symptoms of Alzheimer’s Disease
Most common form of dementia (loss of memory and ability to perform daily tasks)
Affects 10% of people >65
Degeneration in connections of cerebrum.
You have decreasing amounts of forebrain
Alzheimer’s can be genetic
Over create Tou proteins that blocks. So they don’t fire together which decreases connec-tion
