neurons & nervous systems
What are three functions of the nervous system?
Receiving sensory input
Performing integration
Generating motor output
What is the function of glial cells?
Support, protect and nourish neurons
Neuron signaling is possible because...?
each neuron has a charged cellular membrane – “resting” membrane charge
What is a synapse? What are the types of synapses?
synapse: “gap” where information is transmitted from one neuron to the other neuron
types: chemical and electrical
What are the meninges? what fills the spaces between them?
• Meninges – 3-layers that protect the brain
• Spaces between meninges-filled with cerebrospinal fluid
What do the central and peripheral nervous systems contain?
CNS: Brain and spinal cord
PNS: cranial nerves and spinal nerves
mutations in glial cells cause the majority of...
brain tumors
What is the resting membrane potential? What is it based on (list the specific ions)?
resting potential = -70 mV
based on difference in ion concentration inside and outside of the cell (ions = Na+ and K+)
what is a pre-synaptic neuron? what is a post-synaptic neuron?
Transmitting neuron = pre-synaptic
Receiving neuron = post-synaptic
What are the four lobes of the brain?
Lobes = Frontal, Parietal, Occipital, Temporal
What are the three major parts of a neuron? What do they do?
A nucleus within a soma, dendrites (receive signals), and axons (deliver signals)
Which nervous system has more glial cells?
the central nervous system (4)
How is the sodium potassium pump involved in resting potential?
the Na/K pump is responsible for letting in or releasing Na+ or K+. leading to the ion concentration difference
When a neurotransmitter binds, what are depolarization and hyperpolarization known as?
Depolarization - excitatory postsynaptic potential (EPSP)
Hyperpolarization – inhibitory postsynaptic potential (IPSP)
In the spinal cord, what is white matter? what is grey matter? What do the dorsal and ventral horns do?
white matter: myelinates axons
grey matter: cell bodies and interneurons
dorsal horn: convey info from body to brain
ventral horn: convey info from brain to body (movement)
Where do motor neurons accept and transmit signals? Where do sensory neurons accept and transmit signals?
motor neurons: accept from CNS, deliver to muscles and glands
Sensory neurons: accept from sensory receptors, deliver to CNS
What are the similarity and difference between oligodendrocytes and schwann cells?
they both have the same function (form myelin sheath), but oligodendrocytes are in the CNS and schwann cells are in the PNS
What does the refractory period mean?
during an action potential, the Na+ channels will all close and are unable to be stimulated again until a resting period is over.
in a chemical synapse, how are neurotransmitters removed from the synaptic cleft? (include the steps and enzyme used)
1. Diffuses away
2. Degraded by enzymes
3. Recycled by the presynaptic neuron
Acetylcholinesterase: enzyme that degrades the neurotransmitter acetylcholine
What are ALL the functions of the cerebellum and brainstem?
Cerebellum – controls balance and coordination of movement and motor tasks
Brainstem – connects brain to spinal cord
Relay for motor and sensory neurons (between spinal cord and brain)
Controls : Alertness, arousal, breathing, blood pressure, digestion, heart rate, swallowing, walking, sensory information and motor information integration
Name all of the types of neurons and their characteristics
unipolar: one soma, one axon
bipolar: one dendrite, one axon
Multipolar: many dendrites, one axon
pseudounipolar: two axon/dendrites that fuse together to deliver or accept information
All glial cells in the CNS (4) and PNS (2)
CNS:
Oligodendrocytes: form myelin sheath around axons
Astrocytes: provide nutrients and structural support
Ependymal cells: produce cerebrospinal fluid that cushions
the neurons
Microglia: scavenge pathogens and dead cells.
In PNS:
Schwann cells: form the myelin sheath
Satellite cells: provide nutrients and structural support to
neurons
explain the entire action potential graph (I will pull it up)
(1) A stimulus from a sensory cell or another neuron causes target cell to depolarize
(2) Threshold of excitation is reached-all Na+ channels open-membrane depolarizes
(3) Peak action potential-K+ channels open-K+ leaves cell-Na+ channels close
(4) Membrane becomes hyperpolarized K+ ions continue to leave cell. The hyperpolarized membrane is in a refractory period and cannot fire
(5) K+ channels close and the Na+/K+ transporter restores the resting potential
In an electrical synapse, what connects the pre and post synaptic neurons? How do currents travel from cell to cell? Is it faster or slower than chemical synapses?
1. channel proteins (gap junctions)
2. directly from one cell to the other via gap junctions
3. faster
What is the autonomic system? What two divisions make up the system, and what are all of their functions?
autonomic system: regulates activity of cardiac and smooth muscle, and glands
1. Sympathetic division
Especially important during fight or flight responses
Accelerates heartbeat and dilates bronchi
2. Parasympathetic division
Promotes all internal responses associated with a relaxed state
Promotes digestion and retards heartbeat