Neurochemistry Terms

the brain’s ability to reorganize itself by forming new connections between dendrites; changes in the spine/thorn morphology of the dendrites are associated with learning and memory.

Responsible for regulating basic biological needs: hunger, thirst, temperature control

aka the cerebral cortex, which is the outer later of grey matter; responsible for sensing, thinking, learning, emotion, consciousness and voluntary movement.

bridge of fibers passing information between the two cerebral hemispheres

the relay center for the cerebral cortex/cerebrum; handles incoming and outgoing signals

part of the limbic system involved in learning and memory

The pituitary gland is the master gland that regulates other endocrine glands. The pituitary gland releases oxytocin and vasopressin

The pons is involved in sleep and arousal

The midbrain controls Eye movement and auditory and visual reflexes

The brainstem is made up of the pons, medulla and midbrain

The limbic system is made up of the amygdala the thalamus, the hypothalamus and the hippocampus. The limbic system is the emotional brain which is concerned with behavior and emotional expression as well as learning and memory processes

The medulla is responsible for regulating largely unconscious functions such as breathing and circulation

The reticular formation is a group of fibers that carry stimulation related to sleep and arousal through the brainstem. the reticular formation serves as a filter and is inhibited by psychedelics

The spinal cord is responsible for transmitting information between the brain and the rest of the body. the spinal cord handles simple reflexes

The cerebellum is the structure that ordinates fine muscle movement and balance

The amygdala is the part of the limbic system involved in emotion and aggression

The CNS is made up of the brain and spinal cord. the central nervous system functions as an integrative (spinal cord) and control (brain) center

The peripheral nervous system allows for communication between the central nervous system and the rest of the body. The cranial and spinal nerves make up the peripheral nervous system; the peripheral nervous system contain ganglia.

The peripheral nervous system includes the autonomic nervous system and the somatic nervous system

The autonomic nervous system is the visceral motor system and controls involuntary nervous movements. The autonomic nervous system conducts impulses from the central nervous system to cardiac muscles smooth muscles and glands

The somatic motor system is the voluntary motor system. It conducts impulses from the central nervous system to the skeletal muscles

The autonomic nervous system is divided into the sympathetic division and the parasympathetic division however there is also an enteric division

The sympathetic division is part of the autonomic nervous system of the peripheral nervous system. The sympathetic division controls fight or flight responses and mobilizes the body system during activity

The parasympathetic division is a division of the ANS of the PNS. The parasympathetic division controls rest and digest reflexes. It conserves energy, and promotes housekeeping functions during rest

the enteric division is part of the autonomic nervous system. There are two types of neurons in the enteric division. Sensory neurons are neurons that control mechanical and chemical conditions. Motor neurons control peristaltic contractions. The enteric division is part of the gut

1. stimulates flow of saliva
2. lowers the heartbeat
3. constricts bronchi
4. stimulates peristalsis and secretion
5. stimulates release of bile
6. contracts bladder

1. Dilate pupils
2. inhibits flow of saliva
3. accelerates heartbeat
4. dilates bronchi
5. inhibits peristalsis and secretion
6. conversion of glycogen to glucose
7. secretion of adrenaline and noradrenaline
8. inhibits bladder contraction

vision

balance and coordination

neurons that carry signals to the central nervous system for processing. For example sensory neurons

neurons they carry signals from the central nervous system to the peripheral nervous system or two peripheral tissue. These neurons create a response

an afferent neuron; the connects impulses from receptors to the sensory nervous system, impulses include touch, pain, heat, etc.

an efferent neuron that conducts impulses from the CNS to effector organs i.e. muscles

The cell body or soma, the dendrites, and the axon

the cell body is the control center of the neuron; it contains organelles and a phospholipid bilayer with integral proteins; the cell body makes proteins for other parts of the neuron.

the phospholipid bilayer is a powerful insulator that contains many proteins, which are electronically active, such as the voltage gated ion channels.

dendrites receive incoming singles; they are branch like structures that protrude from the cell body and collect incoming signals from other neurons and transfer them to the soma

dendritic spines, or thorns, are small membrane protrusions of a neurons’s dendrite that receive input.

the axon transmits the outgoing electrical signal from the integration center to the end of the axon; axons can vary in length and can branch out, which are called axon “collaterals” or “branches.’

the axon hillock, the axon proper and the axon terminal

the axon hillock is the initial portions that comes out of the cell body – called the axon initial segment – where the action potential (aka nerve signal) is initiated

the axon proper is the middle segment of the axon

the axon terminal, aka the presynaptic terminal, is the terminal where the axon meets its target; houses NT and can contain 40-50 synaptic vessicles

long term potentiation is a long lasting enhancement in signal transmission (interneuronal communication) affected by dendritic spines and an increase in interneuronal connections

long term depression is a reduction in the efficacy of neuronal synapses; LTD is one of several processes that serves to selectively weaken specific synapses in order to make constructive use of synaptic strengthening caused by LTP. This is necessary because, if allowed to continue increasing in strength, synapses would ultimately reach a ceiling level of efficiency, which would inhibit the encoding of new information

sensory neurons (afferent), motor neurons (efferent), and interneurons

interneurons are responsible for the coordination and integration of sensory input and motor output, entirely in the central nervous system, except enteric interneurons

fibers from the central nervous system to the ganglion; the cell body is located in the central nervous system (brain stem or spinal cord) and the preganglionic neuron makes synaptic connections in the ganglia.

ganglia are aggregates of nerve cell bodies in the peripheral nervous system

acetylcholine

parasympathetic = acetylcholine, rest and digest
sympathetic = norepinephrine and epinephrine and acetylcholine

CNS -preganglionic neuron ->Autonomic ganglion -postganglionic neuron -> Target tissue

NT are released from the preganglionic neuron (ACh) and the postganglionic neuron (ACh, NE, E)

glial cells are non neuronal cells. they are any cells that do not directly participate in synaptic interactions and electrical signaling, but have supportive functions for it and help define and maintain the signaling abilities of a neuron; they help hold our nervous system together functionally and they outnumber neurons.

the site of interneuronal communication

the chemical messenger for interneuronal communication

allows nerve impulses to transmit faster; axon is covered in a myelin sheath made up of lipids, proteins, and sphingolipids produced by cells called schwann cells

helps speed up the signal, prevents loss of signal, aids in signal transmission, prevents ion leakage; lipids are cholesterol, sphingomyelin and cerebroside; made up of 75% lipid and 15% protein

the tiny segments of the axon that are exposed after wrapping up of the axon by the schwann cells; we see a high concentration of voltage-gated sodium channels at the nodes of ranvier; excitable patches of the membrane; contain large amount of Nav, Kv, and Na/K-ATPases

-70mV, K

myelinated neurons

nerve cell bodies and dendrites; unmeylinated axons

these make up the myelin sheath for the axon, which insulate axons to form white matter; in the PNS

nonmyelinating schwann cells, encapsulate neurons and form supporting capsules around them; in the PNS

schwann cells and satellite cells

oligodendrocytes; astrocytes; microglial cells; ependymal cells

CNS analogy to Schwann cells; form myelin sheaths around the axons of the CNS

starlike, highly branched cells in CNS; make up ½ of the cells in the brain, 3 main functions: i) take up and release chemicals; ii) take up extracellular K+; iii) feet-like structures surround the blood brain barrier and tighten the barrier, which helps protect the brain from chemical trauma

macrophages; immune system cells, help digest dead neurons and engulf and digest cellular debris, in CNS

neural stem cells; help circulate spinal fluid and produce cerebral spinal fluid (CSF)

serves to protect the brain from chemical injury and is a highly selective barrier that separates the blood vessels from the brain’s extracellular fluid; allows for passage of gases, water and lipophilic molecules

a measure of how badly one area of charge is attracted to another (volts), RMP is -70 millivolts

inside charge (V) – outside charge (V)

an event that makes the intracellular space more positive, and decreases the membrane potential, caused by an influx of positive ions

an event that makes the intracellular space more negative, and increases the membrane potential, caused by an outflux of positive ions or an influx of chloride

transmembrane and integral proteins that allow ions to pass from one side of the lipid membrane to the other

a specific action initiates the opening or closing of the channel, and that action usually precedes the name (i.e. a voltage gated channel, whose gate is opened or closed based on the membrane potential in volts)

not gated; continuously open and allow ions to leak across the membrane; ions flow with the concentration gradient and you find these types of channels all over the neuron

rapid electrical signals that travel undiminished in amplitude (strength) from the cell body to axon terminal; a depolarizing stimulus causes the membrane potential to rise to -55 mV, the threshold potential, and Nav open, causing an influx of Na ions; the cell depolarizes due to the influx of Na, and eventually Nav closes, while Kv opens and K moves out of the cell; the outflux of K causes a repolarization of the membrane, and Kv channels are slow to close, causing hyperpolarization, until the leak channels and Na/K-ATPase cause the return to RMP

opening and closing is affected by the intracellular concentrations of ions

bind chemicals (i.e. ligands, NT or structural analogs) to extracellular receptors, causing opening or closing of channels

voltage gated sodium channels; open at the threshold potential of -55 mV and close at the action potential of +30 mV; cause Na ions to rush into the cell

voltage gated potassium channels; open at the action potential of +30 mV, allow K ions to rush out of the cell, would close at RMP, but are initially slow to close, so they will stay open until about -80 mV, but the leaky K channels and Na/K-ATPase will bring the cell back to RMP and the Kv will close

the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials without needing to increase the diameter of an axon; the action potential is said to “jump” from node to node through the myelinated axon, but really it is diffusion of the sodium ions

something comes in and physically blocks the pore

has to do with voltage and the channel requires reactivation, usually deactivation occurs when the voltage sensor has been reset during repolarization

the major means by which neurons communicate with one another

a mechanism or phenomenon that converts a mechanical or chemical stimulus into a particular cellular response, i.e. the activation of an enzyme, the expression of a protein, or depolarization or hyper polarization; facilitated by receptors

transmembrane protein that accepts signal (extracellularly) and communicates it to the inside of the cell

the chemical or molecule that binds to the extracellular side of a receptor, i.e. a neurotransmitter in ionotropic receptors or a g-protein in metabotropic receptors

i.e. ligand gated ion channel receptors, which bind agonists, resulting in the opening of Na, K and Cl ion channels, resulting in depolarization or hyperpolarization

i.e. g-protein coupled receptors, coupled to a g-protein, so these receptors act on a g-protein when the g-protein agonist binds; cellular response is dictated by the g-protein the receptor is coupled to

ligands that, upon binding, cause the desired cellular response

bind to desired receptor and/or elicit a response

does not bind directly to a receptor but still results in the desired response, or release of NT (i.e. it may block reuptake of a NT or prevent the breakdown of a NT)

bind to receptor but elicits the opposite cellular response

ligands that bind to receptor but do not cause a change in basal level activity of the cell; counteract the affect of the agonists

compete with an agonist for the same receptor

bind to allosteric site and weaken the agonists binding affinity

a calcium sensing protein located on the SV

synaptobrevin is a vesicle associated membrane protein, alternative is VAMP

a tSNARE protein on presynaptic membrane

a tSNARE protein on presynaptic membrane