Chapter 6 : Neuron Fuction & Neuron Transmitters Flashcards
Identify this general part of a neuron. It is the receiving area of a neuron.
Dendrite
This arrow is pointing to that entire middle section of the cell that contains a majority of the organelles. What is it generally called?
Cell body, soma
This arrow is pointing to the center structure inside the cell where DNA is housed. What is it?
Nucleus
This arrow is pointing towards several bundles of white material that are wrapped around a thin gray structure. These bundles function as insulation. What are they collectively called
Myelin sheath
This line is pointing towards a specialized area of the neuron that generates actions potentials when appropriately stimulated. What is it called?
Axon hillock
This arrow is pointing to the long, thin, gray cellular extension inside the white bundles. This part of a neuron conducts or transmits action potentials from the cell body to where neurotransmitters or neuromodulators are released. What is it?
Axon
This arrow is pointing towards the bulbous end of a neuron where it interfaces with another cell by releasing neurotransmitters or neuromodulators. What is that part generally called?
Axon terminal
This arrow is pointing towards the gap between the top neuron and the bottom neuron in that zoomed-in view. What is that gap called?
Synaptic cleft
This arrow is pointing towards the receiving area of the next neuron.
What is that part called?
Dendrite
This division of the nervous system consists of the brain and spinal cord only
Central Nervous system
This branch of the nervous system contains only sensory (afferent) neurons and motor (efferent) neurons.
Peripheral nervous system
This branch of the nervous system is a network of neurons that lines the walls of the digestive tract. We will talk about it more towards the end of the course.
Enteric nervous system
As you learned in your prerequisite Anatomy class, nerves are bundles of many separate axons. Nerves that carry afferent signals only from the periphery to the central nervous system are called
Sensory nerves
Nerves that carry only efferent signals from the central nervous system out to skeletal muscles are called
Motor nerves
Nerves that carry both sensory and motor signals are called
Mixed nerves
This general type of cell is the functional unit of the nervous system
Neuron
For this specific type of neuron, all its components (dendrites, cell body, axon, axon terminals) are contained completely within the central nervous system. These cells are used to spread information from one place in the central nervous system to another.
Interteron
This general kind of cell in the nervous system gets its name from the Latin word for “glue.” These cells are crucial for providing support for neurons and also forming insulation around their axons.
Glial cells
These specific cells form the myelin sheath in the central nervous system. As a part of their name implies, they can typically myelinate “a few” separate neurons with their arm-like extensions.
Oligodendrocytes
These specific cells form the myelin sheath in the peripheral nervous system. They can only wrap themselves around one axon.
Schwann cells
The spaces on the axon that are tiny gaps in the myelin sheath are called
Nodes of raviner
These specific cells form supportive capsules around neuron cell bodies that form ganglia (a cluster of neurons located outside the CNS)
Satellite cells
These glial cells have a highly branched, star-like appearance and have many jobs many jobs, including take up and release of chemicals, providing neurons with substrates for ATP production, and help to maintain homeostasis in the CNS extracellular fluid. These cells are also important for forming the blood-brain-barrier.
Astrocytes
These specialized glial cells are the part of the immune system that resides in the CNS. They remove damaged cells and destroy foreign invaders.
Microglia
These specific cells create a semi permeable layer that separates the fluid compartments of the CNS (ventricles) from the actual brain tissue.
Ependymal cells
This general category of neurotransmitters includes norepinephrine, dopamine, serotonin, and histamine.
Amines
This general neurotransmitter category includes adenosine.
Purines
This is the only gas shown in this table that acts as a neurotransmitter.
Nitric oxide
This specific neurotransmitter has two types of receptors – nicotinic
and muscarinic.
Acteylcholine
Many antipsychotic drugs are antagonists for this neurotransmitter.
Drugs of abuse are also typically agonists of this neurotransmitter.
Dopamine
Molecules such as glutamate, GABA, and glycine belong to this general
family of neurotransmitters.
Amino acids
Alcohol, barbiturates, and benzodiazapines potentiate the effects of
this neurotransmitter
GABA
Curare and alpha-bungarotoxin will block the action of these
acetylecholine receptors, so avoid being shot by poison darts!
Nicotonic
Atropine will block the action of these acetylcholine receptors. This is
why atropine is used to elevate heart rate during anest
Musicarinic
A/an _____ is a rapid change in membrane potential is an “all-or-none” phenomenon and transmits an electrical signal down the axon. This phenomenon is also known as a “spike”.
Action potential
This is a general term for changes in membrane potential in the dendrites or cell body that vary in strength and can be either positive or negative. They also travel very short distances and lose strength rapidly. However, multiple ones in close spatial proximity or close in time add together to travel further or last longer.
Graded potentials
The answer you gave for Question 27 is a general term with two specific sub-types. A(n) _____ is the sub-type that describes a small depolarization.
Excitatory post-synaptic
Also, regarding the general phenomenon in Question 27, a(n) _______ is the sub-type that describes a small hyperpolarizatio
Inhibatory post-synaptic
What is the typical resting membrane potential for a neuron in millivolts?
- 70 MV
If the sum of all graded potentials at the axon hillock surpasses a particular membrane potential called the __________ , the neuron will generate or “fire” an action potential
Threshold voltage
At what membrane potential (in millivolts) will an action potential be generated in a typical neuron
-55mv
When a neuron generates an action potential, it will rapidly depolarize due to the influx of a few of these specific ions.
Na +
During the depolarization phase of an action potential, channels for this specific ion will be slow to open and achieve maximum permeability just after the membrane reaches its maximum potenti
K +
The repolarization of the membrane during an action potential is mostly due to efflux of a few of these specific ions.
K+
The channels mentioned in Question 35 are also slow to close, so they contribute to the __________ phase of the action potential when the cell’s membrane potential dips below its resting level.
Hyperpolarization
When a neuron is in the process of generating an action potential (including the depolarization and repolarization phases), it cannot fire a second action potential, no matter how much additional stimulation it receives. This period is called the
Absolute refract period
As the neuron’s membrane potential is slowly returning to the resting level from a hyperpolarized state, it CAN fire a second action potential IF the next stimulus is larger than normal. This period is called the
Relative refractory period
What…is the specific term for an action potential moving rapidly down a myelinated axon
Saltatory conduction
When an action potential reaches the axon terminal, voltage-gated ____ channels will open and this ion will influx.
Ca 2 +
When that ion from Question 41 moves into the cell, _______ will fuse with the plasma membrane and release whatever signal molecule (a neurocrine) they contain.
Synaptic vesicles
A signal molecule that is released by a neuron into the synaptic cleft could be a neuromodulator or
neurotransmitter
A signal molecule that is released by a neuron into the circulatory system (blood) is called a
neurohormone
If a signal molecule is released into a synaptic cleft, it will bind with receptors on post-synaptic membrane. Eventually the effect of that signal molecule will be turned off by several mechanisms. In some cases, neurotransmitters are degraded by ______ in the synaptic cleft.
Enzymes
n other cases, neurotransmitters will be transported back into the neuron that secreted them for recycling or into a nearby glial cell for degradation. This process is called
Reuptake
Define a autonomic neuron
Involuntary control in the efferent neurons
Define somatic motor neuron
Voluntary control in the efferent neurons. Like skeletal muscles
Define slow axons, transport
It is passive, moves organelles and vesicles by axoplasmic flow of cytosol at .2-2.5
Define fast axons, transport
It is active so it uses ATP. Moves organelles and vesicles at rates of up to 400 mm/day using motor proteins like kinesin
Define anterograde transport
Forward. From the cell body to axon terminal
Define retrograde transport
Backward. Transport from axon terminal to cell body
What ions depolarize a neuron.
Na + & ca 2 +
What ions hyper polarize a neuron
Effluent of k+ or cl- influx
Define subthreshold
Sub : below. No action potential is generated at the axon hillock
Define Suprathreshold
Supra : above. An action potential will be imitated at the axon hillock
Define spatial summation
Summation of several subthreshold signal result in a action potential. Think of two waves comin at you is strong than one wave coming at you
Define temporal summation
No summation. 2 sub threshold graded potentials will not initiate an action potential if they are far apart. On the contrary if they arrive at the trigger zone within a short period of time they may sum and imitate an action potential
The efferent branch of the peripheral nervous system can be subdivided into two general types of neurons. More specifically, the ____ control smooth muscle, cardiac muscle, many glands, and some adipose tiss
Autonomic neuron
These efferent peripheral nervous system neurons always control skeletal muscles.
Somatic motor neurons
Autonomic neurons can also be broken up into two branches that are distinguished best by the type of situation in which they are most active. This branch is dominant in stressful or active situations and is often linked to the “fight or flight” response
Sympathetic branch
This branch of the autonomic nervous system is more active if you are resting quietly after a meal or during the quiet activities of day-to-day living. It is often linked to the phrase “rest and digest.”
Parasympathetic branch
All autonomic neural circuits consist of two neurons connected in series between the central nervous system and the effector. The first neuron, called the ________, has its cell body within the central nervous system.
Pregangolic neuron
The next neuron in the circuit has its cell body outside the central nervous system (in an autonomic ganglion) and projects to an effector organ or target tissue (e.g., the heart).
Postganglic neuron
The preganglionic neurons of both the parasympathetic and sympathetic branches secrete this neurotransmitter.
Acetylcholine
The postganglionic neurons of the sympathetic nervous system secrete this neurotransmitter onto effector cells (e.g., the heart).
Norepinephrine
The postganglionic neurons of the parasympathetic nervous system secrete this neurotransmitter onto effector cells (e.g., the heart).
Acetylcholine
The chromaffin cells of the ________ are modified postganglionic
sympathetic neurons that secrete their neurohormone into the blood
stream.
Adrenal Medulla
The neurohormone secreted by the structure named in Question 12 is
called ____________.
Epinephrine
Input from the _________ nervous system to the lungs will result in airway (bronchiole) dilation to allow more air into the lungs during times of physical or emotional stress.
Sympathetic
Input from the _________ nervous system will cause bronchiole constriction because demand on the lungs is less during times of rest.
Parasympathetic
Heart rate and contraction force are increased by _______ nervous system signaling to increase delivery of O2 and nutrients to the body in times of stress.
Sympathetic
Signaling by the _________ nervous system will decrease heart rate during times of rest.
Parasympathetic
The control of bronchiole diameter and heart rate use input from both the sympathetic and parasympathetic nervous systems. These are both prime examples of _________ control systems that we learned about back at the end of Chapter 6 (Unit 2).
Antagonist
_______ nervous system input to the adrenal medulla will increase the secretion of catecholamines, such as epinephrine, into the blood.
Sympathetic
_______ nervous system input to adipose tissue will increase fat breakdown to mobilize energy stores for increased cellular respiration.
Sympathetic
_______ nervous system input to the kidneys will increase rennin secretion, which is very important for the retention of Na+ and elevation of blood pressure (more on these processes in Unit 5).
Sympathetic
In Questions 19 - 21, only one branch of the autonomic nervous system controls target tissue function. It is the amount of signaling by that one system that determines what the effector organ actually does. These are prime examples of ________ control systems that we learned about back at the end of Chapter 6 (Unit 2).
Tonic
When the pupils receive _________ nervous system input they dilate to bring more light (i.e., visual information) into the eyes. This shouldn’t be shocking, since vision is the primary sense for humans.
Sympathetic
When the pupils receive _________ nervous system input they constrict back to their baseline diameter and therefore allow less light into the eyes.
Parasympathetic
It’s probably not a great idea to devote a lot of energy to digestion during times of physical or emotional stress, right? Well, you should not be surprised to find out that _______ nervous system input decreases digestive motility and secretion.
Sympathetic
By contrast, __________ nervous system input will increase digestive motility and secretion. Hence the classic “rest and digest” phrase that typically describes this autonomic branch.
Parasympathetic
Preganglionic neurons of both the sympathetic and parasympathetic nervous system release acetylcholine onto _________ receptors (specific name) on their postganglionic neurons.
Nn nicotinic
Somatic motor neurons always release acetylcholine onto ______ receptors located on the motor endplate of skeletal muscle cells.
Nm nicotonic
Which of the four major categories of receptors discussed in Chapter 6 (Unit 2) do those receptors from Questions 25 and 26 fall into?
Receptor (ion) channel
Postganglionic parasympathetic neurons also release acetylcholine onto their target cells (e.g., the heart). However, this time, the acetylcholine binds to _______ receptors (specific name).
Muscarnic
Which of the four major categories of receptors discussed in Chapter 6 (Unit 2) do those receptors from Question 28 fall into?
G protein coupled receptor
This subtype of adrenergic receptors is more sensitive to epinephrine than norepinephrine and is found in certain blood vessels and smooth muscle of some organs.
Beta - 2
This subtype of adrenergic receptor also has a higher affinity for norepinephrine than epinephrine, but these are predominantly found in the digestive tract and pancreas.
Alpha-2
This subtype of adrenergic receptors binds equally to norepinephrine and epinephrine and is found primarily on the heart and kidneys.
Beta 1
This subtype of adrenergic receptor is more sensitive to norepinephrine than epinephrine and is found in adipose tissue.
Beta 3
This subtype of adrenergic receptor has a higher affinity for norepinephrine than epinephrine and is the most common on sympathetic target tissues
Alpha 1
All of the adrenergic receptors from Questions 30 – 34 qualify as ______, which was one of the four major categories of receptors introduced in Chapter 6 (Unit 2).
G - protein coupled receptors
Which neuro transmitters are parasympathetic
Acetylcholine
Which neuro transmitter is sympathetic
Norepinephrine, epinephrine
This type of muscle tissue is found only in the heart and helps to pump blood through the circulatory system.
Cardiac muscle tissue
This type of muscle tissue is primarily found in the internal organs and tubes, such as the stomach, urinary bladder, and blood vessels.
Smooth muscle tissue
This type of muscle tissue is attached to the bones of the skeleton, enabling these muscles to control body movement.
Skeletal muscle tissue
When this general kind of skeletal muscle contracts, it brings the centers of two bones closer together.
Flexor
When this general kind of skeletal muscle contracts, the centers of two bones move away from each other.
Extensor
In the left diagram above, #7 is pointing at the _____, which attaches a skeletal muscle to a bone.
Tendon
In the left diagram above, #5 is pointing at a bundle of muscle fibers, also known a(n) _______.
Muscle fascicle
Which andenergic receptor bind to norepinephrine?
Alpha 1, alpha 2 & beta 3
Which adrenergic receptors bind to epinephrine?
Beta 2
Which aderenergic receptors bind to both epinephrine & norepinephrine?
Beta 1
What are the seven categories of neurocrines
Gases, lipids, amino acids, acetylcholine mono amines, purines
GLAAMP
What are the two cholingeric receptors (acetylcholine)
Nicotinic muscular
Nicotinic neuron
In the left diagram above, #3 is pointing at two layers of _______ which surrounds and protects the entire skeletal muscle.
.
Connective tissue
In the left diagram above, #4 is pointing at a single ______, which is the functional unit of the whole muscle.
Skeletal muscle fiber
In the right diagram above, #6 is printed on the _______, which is the specific term for the muscle cell plasma membrane.
Sarcolemma
In the right diagram above, #2 is pointing at tunnels that penetrate deep into the skeletal muscle cell, allowing action potentials to activate all sarcomeres simultaneously.
T-tubules
In the right diagram above, #4 and #9 are pointing at ________ which are organelles that provides a majority of the chemical energy needed for a muscle contraction.
Mitochondria
In the right diagram above, #5 is pointing at a bundle of thick and thin filaments, collectively known as a(n) ________.
Myofibril
In the right diagram above, #1 is pointing at the ______, which is an intracellular organelle that releases Ca2+ ions into the sarcoplasm when the muscle cell is activated by an action potential.
Sarcoplasmic plasmic reticulum
The general term for the site where a somatic motor neuron contacts a skeletal muscle fiber is the ___________
Neuromuscular junction
The specialized part of a skeletal muscle cell at the specific site noted in the previous question is called the ________.
Motor end plate
The neurotransmitter released by a somatic motor neuron onto a skeletal muscle cell is _________.
Acetylcholine
When the receptors in the previous question are triggered, a large amount of this ion will influx through them.
Na +
When the receptors in Question 18 are triggered, a small amount of this ion will efflux through them.
K+
The net depolarization that occurs when these two kinds of ions move across the membrane is called an __________.
End plate potential
These depolarizations mentioned in the previous question always reach threshold and initiate an all-or-nothing __________ that races across the sarcolemma and down the nearest transverse tubule.
Action potential
As the electrical signal mentioned in the previous question moves down the transverse tubules, it will eventually trigger ______ receptors, which are voltage-sensitive proteins.
Dihydropyridine (DHP)
The receptors mentioned in the previous question are mechanically linked to Ca2+ channels on the sarcoplasmic reticulum. These channels are called ___________ receptors and they release Ca2+ into the sarcoplasm.
Ryanodine (RyR)
The Ca2+ ions diffuse to the nearest sarcomere and bind to _______, which becomes activated and moves a protein called tropomyosin.
Troponin
Displacement of tropomyosin allows a motor protein on the thick filament called _______ to bind to actin on the thin filament.
Myosin
When the protein named in the previous question binds to actin, it will flex its head towards the M-line of the sarcomere, pulling the entire thin filament in the same direction, and ultimately contracting the muscle. This flexing and pulling action is called the _______.
Power stroke
The Ca2+ ions released into the sarcoplasm will continue to stimulate a muscle contraction. However, you do not want contraction to last forever. So, Ca2+ ions are actively returned to the sarcoplasmic reticulum by carrier proteins called __________ when stimulation from the somatic motor neuron ceases.
Ca2+-ATPases
These muscle fibers are the most resistant to fatigue, largely because they have many mitochondria, very dense capillaries, and get their ATP from oxidative or aerobic respiration.
Slow twitch oxidative
These muscle fibers make up white muscle, are quick to twitch, but are also easily fatigued.
Fast twitch glycolytic
These muscle fibers make up red muscle and get that color due to large stores of the protein myoglobin, which stores excess oxygen for long term use.
Slow twitch oxidative
These muscle fibers can be thought of as a hybrid between those that develop maximum tension the fastest and those that develop maximum tension the slowest.
Fast twitch oxidative glycoltic
hese muscle fibers have the least mitochondria and the lowest capillary density.
Fast twitch glycoltic
What protein senses the ca 2+ second messenger signal
Troponin
What does troponin do to enable interaction between the thick and thin filaments .
Move tropomyosin to expose binding site
Which specific part of myosin binds to the thin filament?
Myosin crossbridge
What does ATP play in the sliding filament theory
ATP produces energy & cause myosin to detach from actin
Energy from ATP is actually needed @ 3 primary location in the skeletal muscles. Where?
Sodium - potassium pump
Calcium Ca 2+ ATPase pumps
Power stroke
What is a g actin ?
A polymer or long chain of globular actin molecules
Myosin and ATPases catalyze what reaction
Hydrolyze
What is the a band?
Defines the area thick and thin filaments overlap
What is the I band?
The area of a sarcomere that contains the thin filaments in a relaxed muscle
Define Z disk/ line
The structure that defines each end of the sarcomere
What is the m line?
The line run straight down the middle of the sarcomere
What is the H zone
Contains thick filaments in a relaxed muscle
What kind of neuron releases the signal molecule onto a muscle cell?
Somatic motor neuron
What is its signal molecule? What is the name for the specific location on the muscle cell where this release takes place
Acetylcholine. Takes place on motor end plate
To what general kind of receptor will it bind? Pick from the four types discussed in Unit 2?
Receptor channels for nicotonic receptor for Nm
What is the most specific name for this Nicotinic channel receptor? It is permeable to which ion(s)?
Nm, permeable to sodium influx and potassium efflux
What happens to the muscle cell’s membrane potential after binding the neurotransmitter
Depolarization
Specific name for this change? Does it always trigger an action potential at the sarcolemma?
End plate potential, yes
The action potential propagates across the sarcolemma and then enters extensions of the cell membrane called _____ to trigger release of an intracellular messenge
Transverse tubules
What is the intracellular second messenger triggered by an action potential?
Calcium
Where is it stored in muscle cells? What plasma membrane and internal proteins mediate its
release
Sacroplasmic reticulum, DHP and RYR are internal proteins that mediate calcium release
What is the target protein for this intracellular second messenger? What is its effect on that protein and others to which it is attached
Troponin, the calcium bind to troponin moves tropomyosin to allow myosin to make a power stroke. The cuellilargo response is to contract to generate force
