The Nervous System and Endocrine System Flashcards
Specialized cells that transmit and process information from one area of the body to another.
NEURONS
Electrochemical signals that depolarize an axon to send an impulse through the neuron; It is also responsible for activating synapses and signaling neurotransmitters within each axon terminal.
ACTION POTENTIALS
A process in which neurotransmitters get released into the synaptic cleft and activate voltage-gated channels on the postsynaptic membrane of a muscle cell (we’ll discuss the neuromuscular junction later)
SYNAPTIC TRANSMISSION
A neutral cell body of a neuron that contains a nucleus and DNA
SOMA
Extends from the soma and act as signaling wires that communicate with other neurons or regions of the body. They carry impulses that are needed to relay information whether it be towards the CNS or away from the CNS.
DENDRITES AND AXONS
A specialized cell that possesses only one dendrite and one axon.
BIPOLAR NEURON
A specialized cell that possesses many dendrites and one axon.
MULTIPOLAR NEURON
Axons are able to branch into multiple smaller axons called
SYNAPTIC KNOBS/ AXON TERMINALS
Chemical synapses that are released from synaptic vesicles during a synaptic transmission. They travel across a small electrical gap known as the synapsis. In doing so, these are used for various reasons regarding the skeletal, smooth or cardiac muscles and play a vital role in regulating the nervous system.
NEUROTRANSMITTERS
An electrical potential that is found on the plasma membrane of a neuron and reads approximately -70 mV or millivolts. This is when no action potentials are being fired and when the neuron is not in use, yet, the cell is still active.
RESTING MEMBRANE POTENTIAL (RMP)
What is the sodium-potassium pump cycle?
Na/K ATPase pumps 3 sodium ions out of the plasma membrane and 2 potassium ions into the plasma membrane.
Consistently-open channels that allow a certain amount of ions or molecules to diffuse across a plasma membrane.
LEAK CHANNELS
In this process, sodium channels open and an influx of sodium ions diffuse across the membrane, increasing the positivity from -55 to 35mV. This is when an action potential gets fired from the axon hillock and carries an impulses across the membrane.
DEPOLARIZATION
Activated when depolarization comes to an end. The sodium ion channels close and the potassium channels open, allowing an influx of potassium ions to diffuse directly into the axon. This occurs at approximately 35mV until it drops down to -70mV or, if possible, -90mV. It restores the axon back to resting potential.
REPOLARIZATION
-55mV is considered the-
THRESHOLD POTENTIAL
Potassium leak channels and Na/K ATPase pumps function as normal and bring the membrane back to resting potential if the membrane was repolarized to -90mV. This is called-
HYPERPOLARIZATION
Define Saltatory Conduction.
The action potential ‘jumping’ in between gaps of myelin sheaths called nodes of ranviers. This is when action potentials are faster than normal.
A thick layer of proteins that are laid down from glial cells within the PNS and CNS to increase speed of action potentials. They are wrapped around axon membranes like filament paper and release signals.
MYELIN SHEATHS
Only found in the PNS and secrete myelin around a neuron.
SCHWANN CELLS
Only found in the CNS and secrete myelin around an association neuron.
OLIGODENDROCYTES
Explain why sodium and potassium ions aren’t allowed to pass through the membrane when myelin sheaths are present?
Because myelin sheath is wrapped around the sodium and potassium receptors, thus, blocking them off. They are inactivated for now but allows the action potentials to increase in speed.
Specialized, non-neuronal cells that provide structural and metabolic support to many neurons.
GLIAL CELLS
Found in the CNS and guide the necessary production of newly-formed neurons
ASTROCYTES
Found in the CNS and act as garbage collectors
MICROGLIAL CELLS (Microglia)
Found in the CNS and produce as well as regulate cerebrospinal fluid
EPENDYMAL CELLS
Are Na/K ATPase active or passive transport? And why?
Active transport
Do Sodium/Potassium Ions require active or passive transport? Why?
Passive transport
The potential force (rmp, depolarization, repolarization, etc.) doesn’t exist. Please provide an example.
EQUILIBRIUM POTENTIAL
A neuron will not fire another action potential until the previous action potential has officially completed its course, no matter how strong the depolarization is. Sodium channels become inactivated, not CLOSED, until the resting membrane potential has been activated. This is called-
ABSOLUTE REFRACTORY PERIOD
A neuron has depolarization greater than normal due to a hyperpolarized membrane. This is called-
RELATIVE REFRACTORY PERIOD
An electrical junction between the axon terminals and the target cells. It is also between the axon terminals and neuronal cells.
SYNAPSE
Explain electrical synapses
Occurs when the cytoplasm of 2 cells are joined by gap junctions. From there, an action potential will migrate from one cell to another. Common amongst involuntary contractions.
Explain chemical synapses
Found directly at the ends of axons where they meet with their appropriate target cells. This is more or less common in skeletal muscle cells.
It is the most common point of attachment between the axon terminal and a skeletal muscle cell. Explain the entire process.
NEUROMUSCULAR JUNCTION
The enzyme responsible for breaking down acetylcholine molecules from the receptors and recycling them back into the vesicles.
ACETYLCHOLINESTERASE
A neurotransmitter that depolarizes the postsynaptic membrane once it activates the receptors.
EXCITATORY NEUROTRANSMITTERS
A neurotransmitter that repolarizes or hyperpolarizes the postsynaptic membrane.
INHIBITORY NEUROTRANSMITTERS
States that no matter what happens, the action potential will NOT fire if the threshold potential doesn’t reach -55mV.
ALL-OR-NONE LAW
A postsynaptic membrane either decides to fire an action potential or not depending on how many synapses affect the neuron, whether it be excitatory or inhibitory.
SUMMATION
Excitatory neurotransmitters that depolarize a target cell or neuron.
EPSPs (Excitatory Postsynaptic Potentials)
Inhibitory neurotransmitters that hyperpolarize a target cell or neuron.
IPSPs (Inhibitory Postsynaptic Potentials)
A presynaptic neuron fires action potentials so darn fast that both EPSPs and IPSPs pile on top of one another. It just depends on whether or not EPSPs dominate IPSPs or vice versa.
TEMPORAL SUMMATION
Both EPSPs and IPSPs pile on top of each other but cancels out. If both potentials reach the threshold value, then an action potential will fire on the other neuron or muscle cell.
SPATIAL SUMMATION
Receiving information from the PNS to the CNS is known as
SENSORY
Receiving information from the CNS to the PNS is known as
MOTOR
Carries information from the brain, down the spinal cord, and into its desired target cell.
MOTOR NEURONS/EFFERENT NEURONS
Any and all organs or muscles that retrieve information from a motor neuron.
EFFECTORS
Carries info from the target cell to the brain.
SENSORY NEURONS/AFFERENT NEURONS
A motor input response without any conscious thought-processing. It’s like when a doctor taps your knee with a rubber hammer to see if your hamstring will either relax or constrict.
REFLEX
The sensory neuron communicates with a motor neuron on the spinal cord by sending a signal. But instead of that signal going straight to the brain, it dodges a bullet by having the motor neuron implement the signal and fire a response impulse to the muscle which causes the muscle to contract.
MUSCLE STRETCH REFLEX
Define Monosynaptic Reflex Arc.
Same as Muscle Stretch Reflex but involves 2 neurons and 1 synapse.
A short neuron that forms an inhibitory synapse with a motor neuron in which innervates the hamstring muscle.
INHIBITORY INTERNEURON
What are the 2 major categories of the nervous system?
Central and Peripheral Nervous System
Which consists of only the brain and spinal cord?
CENTRAL NERVOUS SYSTEM
Which is everything else that’s NOT the brain and spinal cord? Think of your arms and legs.
PERIPHERAL NERVOUS SYSTEM
The PNS is divided into 2 subcategories. Name them.
Somatic and Autonomic
Typically controls the voluntary muscles so this would be your tendons, which are bone to muscle attachment.
SOMATIC
Typically controls the involuntary muscles such as cardiac (heart) or smooth (digestive).
AUTONOMIC
Now the efferent neurons of the autonomic division are further split into 2 subdivisions: name them.
Sympathetic and Parasympathetic
Considered the ‘fight or flight’ response or ‘stress’ related. This is where your heart rate increases while the GI tract constricts. Example: you see a ghost and that makes you run.
SYMPATHETIC NERVOUS SYSTEM
Considered the ‘rest and digest’ response or ‘peaceful’ related. This is where your heart rate slows down while the GI tract activates more smoothly. Example: you eat popcorn while watching TV.
PARASYMPATHETIC NERVOUS SYSTEM
During a sympathetic response, the adrenal medulla secretes what into the bloodstream? The reason being is because this neurotransmitter can fly through each neuronal response during a ‘stress’ related moment, thus, giving you more energy to run or fight. However, this does affect the homeostatic level of your body at times.
EPINEPHRINE
Myelinated axons in both the CNS and the PNS are called
WHITE MATTER
Unmyelinated somas in both the CNS and the PNS are called
GREY MATTER
What are the names of the white matter found in the brain, spinal cord, and periphery, respectfully?
Tract, tract or column, nerve
What are the names of the grey matter found deep inside the brain, outside the brain, the spinal cord, and the periphery, respectfully?
Nucleus, cortex, horn, ganglion
Name the three main divisions of the brain.
Prosencephalon (forebrain), mesencephalon (midbrain) and the rhombencephalon (hindbrain)
Usually a clear fluid found in the brain and spinal cord until it collects nutrients and waste needed to be cleaned out by the microglia.
CSF (Cerebrospinal fluid)
What are the 3 parts of the rhombencephalon?
Medulla oblongata, pons varolii, cerebellum
Sits directly below the pons and above the spinal cord. As a matter of fact, it is the only attachment of the brain to the spinal cord. It relays information and regulates vital functions that the body needs like digestion. You damage this, you’re headed to a coffin early.
MEDULLA OBLONGATA
Sits directly above the medulla and below the midbrain. It is the connection point between the brainstem and cerebellum. It controls autonomic functions, antigravity posture and maintains balance. You damage this, you’re also headed to a coffin early.
PONS
Sits behind the pons. It is a site where more complex information gets integrated and how a smooth execution takes place. I like to call this either the meeting room or the benchwarmer where if no other parts of the brain is able to understand the info, then this guy can. You damage this, you lose balance of hand posture as well as possible movement.
CEREBELLUM
Located right above the pons and below the thalamus. It is the relay center for visual and auditory information of the reticular activating system (RAS).
MIDBRAIN
The midbrain, pons and medulla make up what?
BRAINSTEM
The prosencephalon divides into what?
Diencephalon and Telencephalon
Diencephalon consists of what? Hint: 2 only.
Thalamus and Hypothalamus
Sits above the midbrain and is responsible for relaying sensory information.
THALAMUS
Sits next to the midbrain and is responsible for controlling emotions, activating glands to release hormones, and many autonomic functions.
HYPOTHALAMUS
The telencephalon consists of what?
The entire cerebrum
True or False? The spinal cord up to the telencephalon is symmetrical.
False! It is only up to the diencephalon.
Left Hemisphere controls what?
Right side of body
Right Hemisphere controls what?
Left side of body
Both hemispheres intersect at a region known as? And both hemispheres are held by?
Corticospinal tract. Corpus callosum.
Unmyelinated somas that run across the surface of the brain, primarily the sulci and gyrus.
CEREBRAL CORTEX
Both hemispheres are responsible for-
Thought-processing and intellectual functions in coordination.
Name the 4 lobes of the cerebral cortex.
Frontal, parietal, temporal, occipital
This lobe initiates all means of voluntary movement, cognitive-thinking, and problem-solving.
FRONTAL LOBES
This lobe deals with sensations (taste, touch, pressure, temperature)
PARIETAL LOBES
This lobe deals with short-term memory, language comprehension, auditory and olfactory sensation.
TEMPORAL LOBES
This lobe deals with visual perception and sensation.
OCCIPITAL LOBES
