Nervous System Test Flashcards
What is a concentration gradient?
Difference between concentration of a substance in two compartments
How do you calculate the concentration gradient?
ION(out) - ION(in)
What is excitability?
The ability of a cell to send and receive electrical signals across the plasma membrane
What does it mean to move down the concentration gradient?
From high to low concentration
What does it mean to move up the concentration gradient?
From low to high concentration
What is electrostatic repulsion?
When like charges repel
What is equilibrium potential?
There is no net flux (no change in the ion concentration)
What is an action potential?
A Rapid sequence of changes in the voltage across a membrane
What are the steps of an action potential? (start to finish)
- Na+ gates open allowing Na+ to enter and depolarize the cell.
- The neuron reaches threshold and an action potential is propagated along the axon.
- The action potential peaks and Na+ gates close.
- K+ gates open and K+ exits the cell causing repolarization of the cell.
- K+ efflux and the Na+/K+ pump cause hyperpolarization of the cell.
- Natural leaky cells establish resting membrane potential.
What are dendrites?
The site of signal input
What is the soma?
Cell body
What happens at the axon hillock?
Action potential is generated
What is an axon?
The long string like part of the neuron that signals are sent down
What is the axon terminal?
The site of signal output
What is a synaptic cleft?
The gap between two cells filled with interstitial fluid
What is a postsynaptic cell
The neuron located after the synapse that receives the signal
What is a graded potential?
A change in the electrical potential on the membrane of an excitable cell
What are the three channels present in the axon hillock?
K+ voltage gated channels
K+ leak channels
Na+ voltage gated channels
What are the two types of circuits?
Converging and diverging
Where does a converging circuit start?
A converging circuit starts in the PNS (sensory impulse)
Where does diverging circuit start?
Starts in the CNS (motor impulse)
What does a motor tract do?
Send signals from CNS to PNS
What does a sensory tract do?
Send a signal from PNS to brain (located in CNS)
What are the main two organs of the CNS?
The brain and spinal cord
What are 90% of the cells in the CNS?
Neuroglia
What are 10% of the cells in the CNS?
Neurons
What is the CNS supported by?
Cerebral spinal fluid (CSF)
What is an Axon?
Long thread like part of the neuron which impulses are sent from one cell body to another
What is the meninges?
A protective structure for the CNS
What are the three layers of the meninges? (superficial to deep)
- Dura mater
- Arachnoid mater
- Pia mater
What are the qualities of the Dura mater?
Thick, strong connective tissue layer
What are the qualities of the Arachnoid mater?
Thin, transparent fibrous membrane
What are the qualities of the Pia mater?
Delicate connective tissue layer
What are the functions of cerebrospinal fluid?
- Homeostatic regulation
- Support and cushioning
- Chemical and immunological buffering
What is the function of ventricles?
- Store CSF
- Provide a continuous flow of CSF between the brain and spinal cord
How does CSF move through the brain?
Ventricles
How is CSF produced?
Specialized tissues called choroid plexus and ependymal cells
What is the function of the blood brain barrier?
Tightly regulate the movement of ions, molecules, and cells between the blood and the brain
What type of cell is a neuron?
An excitable cell