Unit review video 3 neuro system Flashcards
What is the function of the nervous system?
To Provide commutation from the external environment to the internal environment. (Control center of the body)
Explain the structural divisions of the nervous system.
Central nervous system
- Brain
- Spinal Cord
Peripheral Nervous system
- Nerves
- Ganglia
Explain the functional divisions of the nervous system.
Central nervous system
- Integration (receives information and makes decisions with information)
Peripheral Nervous system
- Sensory: Recieve information
- Motor: Send information
The motor is divided into somatic and autonomic.
The function of Somatic and Autonomic. (PNS Motor)
Somatic
- Send signals to skeletal muscle ( voluntary control)
Autonomic
- Send signals to cardiac, smooth muscle, and glands.
The function of Visceral and somatic.
(CNS)
Visceral
- Send a message to deep organs from inside
somatic
- send message From outside to deep organ.
Neuroglia in the Central Nervous system.
- Astrocytes: Protect
- Microglia: Immune cells (phagocytes)
- ependymal cells: Move Cerebral spinal fluid
- Oligodendrocytes: Form the myelin Sheath
Neuroglia in the Peripheral nervous system.
- Schwann cells: Create Myelin sheath
- Satellite: Protect cell bodies of neurons
What is the function of Neuroglial cells?
To support and protect neurons.
Neuron parts and functions.
- Dendrites: Recieve messages ( more dendrites the more you receive)
- Cell body: Control center of neuron
- Axon: Send messages
What is the difference between a nerve and a tract?
Nerve: Bundle of axons in the Peripheral nervous system
Tract: Bundle of axons in Central nervous system.
Where are the Nucelous and Ganglia found?
Nucleus: found in Central nervous system
Ganglia: Perphial nervous system (cell body)
Explain the importance of the myelin sheath and describe how it is formed in the central and peripheral nervous systems
Central nervous system
- Oligodendrocytes: Wrap around the axon, leaving spaces called nodes of Ranvier
Peripheral nervous system
-Schwann cells: Wrap around the axon, leaving spaces called nodes of Ranvier
These are insulated, leading to the speed of transmission.
Characteristic of a neuron.
- Send and receive
- Electrical
- Excitable
- Long-lived (100 years +)
- Amitotic (Dont divide)
Define resting membrane potential and describe its electrochemical basis.
Resting membrane potential
- Positive on the outside
- Negative on inside
- (-70) on inside
- sodium-potassium pump 3 Na+ outside K+ inside
- K+ is leaking out through leak channels
- nothing happens
Compare and contrast graded potentials and action potentials.
Graded potentials: Graded potentials are triggered by various stimuli, such as neurotransmitters binding to receptors, mechanical stimulation, or changes in ion concentrations.
Action potentials are triggered when the membrane potential reaches a certain threshold, typically around -55 to -50 millivolts. This threshold must be reached to initiate an action potential.
Define absolute and relative refractory periods.
The absolute refractory period ensures that action potentials are discrete events and prevents the neuron from generating overlapping signals
relative refractory period temporarily reduces the neuron’s excitability, requiring a stronger stimulus to initiate another action potential.
Types of graded membrane potential
EPSP: Deporazation positive (Na+) trigger action potiental
IPSP: Hyperpolerize negative (k+)
Where does action potential begin?
Axon Hillock
Define saltatory conduction and contrast it to conduction along unmyelinated fibers
Saltatory conduction: More efficient because no ions leak out. It’s quicker. Myelin sheath is hydrophobic, which keeps ions moving faster through voltage-gated channels.
Unmyelinated Ions can leak out, which leads to slower.
What channels are on the cell body?
Ligand-gated channels
What channels are on the axon?
Voltage-gated channels
What is Snyapes
The space between a neuron and something else. Communication area between another neuron, muscle, or gland
Distinguish between electrical and chemical synapses by
structure and by the way they transmit information
Chemical synapses are none fused synapses( slower)
Electrical synapses Are fused faster. Communicated through gap junctions.
Distinguish between excitatory and inhibitory postsynaptic potentials.
EPSP: ligand-gated channels open sodium rushin, making the membrane more positive to -55mV. Depolarization. ( start action potienal)
IPSP: K+ channel opens or chlorine, and K+ rushes out, making it more negative -80 mV. Hyperpolarization. (stop action potential)
Describe how synaptic events are integrated and modified.
synaptic events are integrated and modified through spatial and temporal summation of excitatory and inhibitory inputs, determining whether the postsynaptic neuron will fire an action potential.
Define neurotransmitters and name several classes of neurotransmitters.
A neurotransmitter is a chemical substance that transmits signals across a synapse, which is the junction between neurons or between a neuron and an effector cell (such as a muscle or gland cell)
- Amino Acids
- Monoamines
- Acetylcholine
- Neuropeptides
- Gasotransmitters
- Purines
Describe common patterns of neuronal organization and processing.
CNS neurons are organized into several types of neuronal pools, each with distinguishing patterns of synaptic connections called circuits.
The four basic circuit types are diverging, converging, reverberating, and parallel after-discharge.
