Lecture Exam I Flashcards
Functions of the nervous system
Primary control (responding to stimuli)
Higher functions ( cognitive skills)
Neurons
Basic structural unit of the nervous system, the excitable cells that transmit electrical signals
Glial cells
Nonexcitable cells that primarily support and protect neurons
Types of neurons
Multipolar
Bipolar
Pseudounipolar
Sensory neurons
Afferent neurons conduct from somatic and visceral receptors
Pseudounipolar, few bipolar
Motor neurons
Efferent neurons conduct motor output
Multipolar
Interneuron
Association neurons receive process and store information, 99% of neurons
What created the membrane potential in neurons? List three factors that contribute to the negative charge inside the cell
3Na+/2K+ pump
More protein in the cell than out of the cell
Phosphate groups
What would happen to a neuron’s ability to conduct a nerve impulse if the resting potential didn’t exist?
The cell would remain inactive, so it would not conduct an impulse
Leak and gated channels (three types of gated channels)
a. Chemically gated channels
b. Voltage-gated channels
c. Leak channels
Action potential
Localized change in electrical potentional
propagation of action potential
Propagates toward neuromuscular junction
Describe events in the neuromuscular junction
c. Action potention reaches synaptic knob
i. Calcium channels open
ii. Release neurotransmitter in the synapse
iii. Neurotransmitter for skeletal muscles is always actelycholine
iv. Receptors for muscle are Na+ channels (chemically gated)
v. Na+ enters muscle fiber – triggering contraction of muscle
vi. Acetylcholinesterase residing in the synaptic cleft, enzyme that breaks down Ach molecules
All or none principal
If threshold reached, action potential propagated. If threshold is not reached, no action potential propagated.
Spatial summation
(axon hillock) release of neurotransmitter from multiple presynaptic neurons.
Temporal summation
(axon hillock) repeated release of neurotransmitter at same location.
EPSP
inside of neuron becomes more positive (less negative). propagate toward axon hillock Na+ flows into neuron.
IPSP
inside of neuron becomes more negative. Propagate towad axon hillock. K+ or Cl- flows into neuron.
What is refractory period?
This is the time during which another stiumuls given to the neuron will not lead to a second action potential.
Absolute refractory
no amount of stimulus will generate a second action potential
Relative refractory
with greater stimulation action potential is possible
Absolute refractory physiology
voltage-cated channels opened than closed in inactivated state. Remain closed until potential almost to resting potential.
Relative refractory Physiology
neuron hyperpolarized. Voltage-gated channels return to resting state.
Satellite cells
surround neuron cell bodies in ganglia. Regulate O2, CO2, nutrient, and neurotransmitter levels around neurons in ganglia, found in peripheral nervous system.
Neurolemmocytes: schwann cells
surround axons is PNS, are responsible for myelination of peripheral axons, participate in repair process after injury, found in peripheral nervous system.
Oligodendrocytes
myelinate CNS axons, provide structural framework, found in central nervous system.
Astrocytes
maintain blood-brain barrier, provide structural support, regulate ion, nutrient, and dissolved gas concentrations, absorb and recycle neurotransmitters, form scar tissue after injury, found in central nervous system.
Microglia
remove cell debris, waste, and pathogens by phagocytosis, found in central nervous system.
Ependymal cells
line ventricles (brain) and central canal (spinal cord), assist in producing, circulating, and monitoring of cerebrospinal fluid, found in central nervous system.
Saltatory and continuous conductions. Compare and contrast
Continuous conduction occurs in neurons with unmyelinated axons whereas saltatory conduction occurs in neurons with myelinated axons. Saltatory conduction is much faster than continuous conduction.
What is synapse?
a. Region where axon terminal meets its target cell
Types of synapses
Chemical and electrical
What type of synapse is the most common in nervous system?
Chemical synapses are most common in the nervous system.
Curare binds to the Ach receptor without activating them. What is the effect of curare on the skeletal muscle?
Paralysis; life-threatning (wont be able to breathe)
The botulism toxin prevents the release of the neurotransmitter into the synapse. What will be the consequence?
Paralysis
Structures of the brain and their main functions.
Brain structure and function (already made flashcards on this question)
Brain protection. Name four structures that protect the brain.
a. Cranium provides rigid support
b. Meninges that surround the brain
c. Cerebrospinal fluid cushions
d. Blood-brain barrier (prevents entry of harmful materials.
CSF production and flow.
a. Produced by choroid plexus
b. Circulates through
i. Lateral ventricle – third ventricle – aqueduct – fourth ventricle – subarachnoid space – arachnoid villi – drains into Dural venous sinuses
A drug that blocks ATP production is introduced into an isolated axon preparation. The axon is then repeatedly stimulated, and recordings are made of the response. What effects would you expect tot observe? How propagation of action potential will be affected? Why?
Sodium pumps and potassium pumps will not be triggered to open or close. The cell will not reach the threshold to propagate a reaction, because the pump will remain unmoved.
Reflex: definition, types, components.
Are rapid, preprogrammed, involuntary responses of muscles or glands to a stimulus.
Spinal reflex or cranial reflex, somatic reflex or visceral reflex, monosynaptic reflex or polysynaptic reflex, ipsilateral reflex or contralateral reflex, innate reflex or acquired reflex.
Reflexes including a sensory receptor, an effector, and the neural wiring between.
Cerebral cortex: primary, association, and functional areas.
Primary: senses. The abilities to sense something in general or special senses.
Association: putting senses with memories. See a pen know it is a pen etc…
Functional areas: motor responses, acting about the senses sensed from the primary region.
- What is Receptor? Types and function of receptors.
a. Structures specialized to respond to changes in the environment.
b. By modality: Nociceptors, Thermoreceptors, Mechanoreceptors, Chemoreceptors.
Spinal cord: organization of white and gray matter. What is found within white matter? What is found in the ventral horns of spinal cord? What is found in the dorsal horns of spinal cord?
White matter: posterior funiculus, lateral funiculus, white commissure, anterior funiculus.
Ventral horns: cell bodies of motor neurons
Dorsal horn: sensory nuclei that receive and process incoming somatosensory information.
- Spinal nerves: how many pairs, type (all mixed!) What are the components of spinal nerve? What is found within ventral root? What is found within dorsal root? what is found within dorsal root ganglion? What is ventral ramus? What is dorsal ramus?
31 pairs of spinal nerves
Components of spinal nerve: dorsal root, ventral root, dorsal root ganglion, spinal nerve, posterior ramus, anterior ramus
Ventral root: contains axons of motor neurons.
Dorsal root: contains axons of sensory neurons.
Dorsal root ganglion: collection of neuronal cell bodies
The ventral ramus is the larger portion and is in the anterior and lateral trunks, upper and lower limbs.
The dorsal ramus is the smaller portion and is in deep muscles of back and skin of back.
