Nervous System + nervous Tissue pt. 1
What are the two main divisions of the nervous system and what structures make up each system?
Central Nervous System - brain and spinal cord
Peripheral nervous system - all nerves outside of the brain and spinal cord
What are ependymal cells and what are their purpose?
Ependymal cells are found in the choroid plexus of the lateral ventricles, responsible for producing cerebrospinal fluid
What are the different types of gated ion channels? What triggers each channel type?
Ligand-gated channels - triggered by neurotransmitters (chemical signals)
Voltage-gated: triggered by changes in membrane voltage
Mechanically-gated: triggered by physical stretching or distortion
What is the process of neurulation?
The shaping and closing of the neural tube
What secondary brain vesicles arise from each primary brain vesicle and around what week of embryologic development do they appear?
Prosencephalon -> telencephalon +diencephalon
Mesencephalon -> midbrain (doesn't divide further)
Rhombencephalon -> metencephalon + myelencephalon
appear around week 5
The peripheral nervous system can be broken down into subdivisions. What are the two main subdivisions of the PNS?
The afferent (sensory) division
The efferent (motor) division
What makes up the blood brain barrier?
Astrocytes and tight junctions
When does a graded potential trigger an action potential
if the graded potential reaches its threshold (depends on magnitude of stimulus strength) it will trigger an action potential.
Which embryonic germ layer forms the neural plate and thus most of the nervous system structures?
Ectoderm
The neural tube lumen develops into what structure(s) of the adult brain
the ventricular system (spaces to produce + circulate cerebrospinal fluid)
The efferent division of the PNS can be broken down into the somatic and autonomic nervous systems. What do each of these systems control?
Somatic - control of voluntary muscle
Autonomic - control of involuntary muscle + glands
What is the resting membrane potential of a neuron? What maintains a neurons membrane potential
-70mV
Membrane potential is maintained by leak channels and gated channels, specifically voltage gated channels (Na+/K+ pump)
What is the difference between excitatory communication and inhibitory communication between a neuron and its target?
Excitatory communication - encourages firing an action potential
Inhibitory communication - prevents firing an action potential
Once the neural tube has closed, the _______ end will give rise to the brain, and the ________ end will give rise to the spinal cord
cranial; caudal
What structures are included in the diencephalon
Hypothalamus
Thalamus
pineal gland
pituitary gland
microglia are the immune cell of the CNS. They help protect the brain against infections and keep the environment stable
Is an action potential more or less likely to fire if it is hyperpolarized?
Less likely (moves away from 0 to become more negative & discourages firing)
What two things can occur at the postsynaptic neuron that either hyperpolarizes or depolarizes the membrane
Excitatory postsynaptic potentials (EPSPs)
Inhibitory postsynaptic potentials (IPSPs)
Neural crest cells give rise to:
Most PNS structures (i.e. nerves outside of the CNS)
What is the main purpose of the thalamus?
The thalamus receives all sensory information (other than smell) and sends it to the correct area of the brain for processing
Which cells are responsible for producing myelin in the CNS? Which cells produces myelin in the PNS?
Oligodendrocytes produce myelin in the CNS
Schwann cells produce myelin in the PNS
What are the three neuron structure types and where are they found?
Multipolar neurons: found in motor neurons + interneurons
Bipolar neurons: found in special senses
Unipolar neurons: found in sensory neurons of the PNS
Neurons communicate with each other at _________, which are small gaps that allow signals to pass
synapses
What are the primary brain vesicles? During which week of embryonic development do these appear?
Prosencephalon, mesencephalon, rhombencephalon
Develop around week 4
What is the purpose of the hypothalamus?
Monitors autonomic functions (temperature, heart rate, hydration levels, etc.) and controls the secretion of certain hormones