bio Psych Test 1
What is the correct sequence of chemical events at the synapse?
1) the neuron synthesizes chemicals that serve as a neurotransmitter. it synthesizes neurotransmitters in the axon terminals and synthesizes neuropeptides in the cell body 2) action potentials travel down the axon. at the presynaptic terminal, an action potential enables calcium to tenter the cell. calcium releases neurotransmitters from the terminal into the synaptic clef 3) neurotransmitter binds to receptor and diffuse across the cleft 4) separation from receptors 5) the neurotransmitter molecules may be taken back into the presynaptic neuron fro recycling or they may diffuse away 6) some postsynaptic cell send reverse messages to control the further release of neurotransmitter by presynaptic cells
What are glia and what are the different types of glia responsible for?
A supportive cell in the central nervous system. Unlike neurons, glial cells do not conduct electrical impulses. The glial cells surround neurons and provide support for and insulation between them Glial cells are the most abundant cell types in the central nervous system. Types of glial cells include oligodendrocytes (brain and spinal) , radial (migration of neurons in embryonic development), astrocytes(synchronizes the activity of axons, shields, and enables them to transmit messages in waves), Schwann cells (build myelin sheaths that surrounds the axons) , and microglia (immune system)
When do action potentials occur and what affects their speed?
Action potentials are caused when different ions cross the neuron membrane. A stimulus first causes sodium channels to open. Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron. 2 factors that affect the speed at which action potentials propagate are (1) the diameter of the axon and (2) whether the axon is myelinated. Large-diameter axons propagate action potentials faster than do small-diameter axons. Myelinated axons propagate action potentials faster than unmyelinated axons (of the same diameter).
Know the all the divisions of the nervous system and their functions.
Central nervous system (CNS): is the brain and the spinal cord peripheral nervous system (PNS): connects the brain and the spinal cord to the rest of the body somatic nervous system: part of the PNS, which consists of the axons conveying messages form the sense organs to the CDs and from the CNS to the muscles autonomic nervous system: controls the heart, intestines, and other organs. the autonomic nervous system has some of its cells bodies within the brain or spinal cord in clusters along the side of the spinal cord
Know the parts of the presynaptic terminal.
Dendrite > Cell body > Axon hillock > Axon > Presynaptic terminal When the action potential reaches the presynaptic terminal, it provokes the release of a small quantity of neurotransmitter molecules, which bind to chemical receptor molecules located in the membrane of another neuron, the postsynaptic neuron, on the opposite side of the synaptic cleft.
Know how those potentials affect the action potential differentially.
Depending on the sum total of many individual inputs, summation may or may not reach the threshold voltage to trigger an action potential. excitatory are more likely to fire an action potential while inhibitory are less likely to generate an action potential
What are the easy and hard problems of brain activity?
Easy problems" focus on differences in conscious states and their mechanisms. "Hard problems" focus on why and how brain activity is associated with consciousness.
Neurons can release more than one neurotransmitter. What is the advantage of this?
Having more than one transmitter lends considerable versatility (able to adapt to many functions) o synaptic transmission.
• Know the difference between ionotropic and metabotropic effects on the postsynaptic cell.
Ionotropic effect: synaptic effects that depend on the rapid opening of some kind of gate in the membrane (less than a millisecond; depend on glutamate or GABA) metabotropic: a sequence of metabolic reaction that produce slow and long lasting effects than the ionotropic at a synapse (few second or longer; depend on dopamine, serotonin, norepinephrine, and GABA Glutamate at times too)
What is Korsakoff's syndrome?
Korsakoff syndrome is a chronic memory disorder caused by severe deficiency of thiamine (vitamin B-1). Korsakoff syndrome is most commonly caused by alcohol misuse Thiamine (vitamin B-1) helps brain cells produce energy from sugar. When levels fall too low, brain cells cannot generate enough energy to function properly. As a result, Korsakoff syndrome may develop.
What is PKU and what are its genetic and environmental inputs
PKU: a genetic inability to metabolize the amino acid phenylalanine. If PKU is not treated, phenylalanine accumulates to toxic levels, impairing brain development and leaving a child mentally retarded, restless and irritable. PKU is a trait with high heritability that can be modified by environmental interventions such as a strict diet. people have to avoid meats, eggs, dairy products, grains and especially aspartame 1% of Europeans carry a recessive gene for PKU
Know the state of the sodium and potassium channels at rest and during an action potential.
Rest: ' When a neuron is not sending a signal, it is "at rest." When a neuron is at rest, the inside of the neuron is negative relative to the outside. Although the concentrations of the different ions attempt to balance out on both sides of the membrane, they cannot because the cell membrane allows only some ions to pass through channels (ion channels). At rest, potassium ions (K+) can cross through the membrane easily. Also at rest, chloride ions (Cl-)and sodium ions (Na+) have a more difficult time crossing bc sodium is more concentrated outside and potassium inside Action The formation of an action potential can be divided into five steps. (1) A stimulus from a sensory cell or another neuron causes the target cell to depolarize toward the threshold potential. (2) If the threshold of excitation is reached, all Na+ channels open and the membrane depolarizes. (3) At the peak action potential, K+ channels open and K+ begins to leave the cell. At the same time, Na+ channels close. (4) The membrane becomes hyperpolarized as K+ ions continue to leave the cell. The hyperpolarized membrane is in a refractory period and cannot fire. (5) The K+ channels close and the Na+/K+ transporter restores the resting potential.
Know about spatial and temporal summation.
Temporal: repeated stimulation in one place; over time ex: one pinch of a dog's foot did not evoke reflexes, but pinching a dog's foot repeatedly did spatial: multiple simultaneous inputs; over space ex: instead of pinching one point twice, he pinches two points at the same time
What is the concentration gradient and electrical gradient and how do they work?
The electrical and concentration gradients of a membrane tend to drive sodium into and potassium out of the cell, and active transport works against these gradients. electrical: also known as polarization - a differences in electrical charge between the inside and outside of the cell neurons concentration gradient: difference of ions across the neuron's membrane
What are the ventricles and what do they do?
The ventricles of the brain are a communicating network of cavities filled with cerebrospinal fluid (CSF) and located within the brain parenchyma.
Know the role of genetics in facial expressions.
a contribution of the environment is obvious but a research done on blind people found that they never imitated their relatives yet they smiled just like them which results suggests that genetics does play a major role in controlling facial expressions
What is the difference between a hormone and neurotransmitter?
a hormone is a chemical secreted by cells in one part of the body and conveyed by the blood to influence other cells. a neurotransmitter is alike a telephone signal: it conveys a message from the sender to the intended receiver. hormone function more like a radio station: they convey a message to any receiver tuned to the right station
Know the definition of synapse.
a specialized gap as a point of communication between two neurons
Which neurotransmitters are synthesized from which amino acids? (See figure 3.14)
acetylcholine, is synthesized from choline, which is abundant in eggs, milk and peanuts the amino acids phenylalanine and tyrosine, present in proteins, are precursors of dopamine, norepinephrine, and epinephrine. tryptophan, the precursor to serotonin, crosses the blood brain barrier by special transport system that it shares with other large amino acids
Be able to answer questions about Sperry's newt experiments
after he cut the optic nerve of a frog and inverted the inverted the axons grew back to their original targets, not to the targets corresponding to the eye's current position
How do the sympathetic and parasympathetic nervous systems interact?
after the sympathetic nervous system increases the activity of an organ the parasympathetic relaxes the organ and brings it back to normal
What are dendrites and what are the characteristics of dendrites?
are branching fibers that get narrower near their ends (like a tree) specialized with synaptic receptors which They receive other information from other neurons; the greater the surface area of a dendrite the more information it can receive
How do we know neurons are separate from one another?
because of the synapses
Why do neurons live or die during development?
because the nerve growth factor promotes the survival and growth of the axon and if they do not receive NGF then it's cell body dies
How do the brains of blind people differ from sighted people?
blind people improve their attention to touch and sound by practice. for blind people the occipital cortex also responds to auditory information and touch when in normal people is just for vision
What are drugs that block or mimic the effect of the neurotransmitter called?
block: amphetamine, cocaine and Methamphetamine, block reuptake of dopamine (reward/pleasure/attention/memory), Serotonin (mood, sleep, desire, appetite), and Norepinephrine (sensory processing, movement and anxiety) Mimic: Opioid drugs such as heroin and OxyContin, for example, chemically resemble the brain's natural opioids sufficiently to engage and stimulate their specialized receptors. Marijuana and hashish mimic cannabinoid neurotransmitters, the most important of which is anandamide. Hallucinogen
Know the terms for anatomical directions in the nervous system (see figure 4.2 and table 4.1).
dorsal: mean toward the back of the torso ex: shoulder blades are dorsal to the ribs ventral: toward the front of torso/belly superior: toward the head inferior: toward the feet anterior: toward the front posterior: toward the rear proximal: closer to the point of attachment with the torso ex: the elbow is proximal to the wrist lateral: father from midline ex: the eyes is lateral to the nose distal: father from the point of attachment. ex: the ankle is distal to the knee medial: closer to the midline, or diving line between right and left ex: neck is medial to the shoulder
When are brains most damaged by teratogens, infections, or deficiencies in nutrition?
during early development; gastrulation is one of the early stages of embryological development
What is heritability and how is it studied?
estimate of the degree to which variation in a characteristics depends on genetic variations in a given population you study it by looking at three kinds of evidence: 1) comparing monozygotic twins to dizygotic twins 2) studies of adopted children: wether is genetics or parental influence 3) identify specific genes linked to some behaviors
What are each of the cerebral cortex lobes generally responsible for?
frontal lobe: controls our emotions, abstract thought, planning of movement; temporal lobe: hearing, understanding language and advanced visual processing like recognizing someones face or perception of movement parietal lobe: body sensations occipital lobe: vision; primary vision cortex
Know what genes and chromosomes are.
genes: units of heredity that maintain their structural identity form one generation to another chromosomes: strands of genes that also come in pair. the only exception to this rules are male mammals since they have the XY chromosome
What is gray and white matter in the brain and spinal cord made up of?
gray matter is densely packed with cell bodies and dendrites. many neurons from the gray matter of the spinal cord send axons to the brain or to other parts of the spinal cord through the white matter, containing myelinated axons. t is present in the brain, brainstem and cerebellum, and present throughout the spinal cord. The gray matter includes regions of the brain involved in muscle control, and sensory perception such as seeing and hearing, memory, emotions, speech, decision making, and self-control .In the spinal cord and cerebrum gray matter is surrounded by white matter. However, in the cerebellum and cerebral hemispheres this is reversed with the grey matter surrounding underlying white matter.
Know the general purpose of each structure in the brain as listed in figure 4.10
hindbrain: the posterior part of the brain consists of the medulla, the ponds and the cerebellum forebrain: The forebrain is the division of the brain that is responsible for a variety of functions including receiving and processing sensory information, thinking, perceiving, producing and understanding language, and controlling motor function midbrain: a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation. cranial nerves: control sensations from the head, muscles movement in the head and much of the parasympathetic output tot he organs medulla: controls vital reflexes including breathing, heart rate, vomiting, salivation, coughing and sneezing cerebellum: large hindbrain structure with many deep fold; it controls movement and it's described as important for "balance and coordination"
Know what homozygous and heterozygous mean.
homozygous: anyone with an identical pair of genes on the two chromosomes for example, having brown eyes because the brown eyes is dominant gene BB heterozygous: an individual with an unmatched pair of genes for example. you might have a gene for blue eyes on one chromosome and a gene for brown eyes on the other
How did Loewi's experiment confirm the role of chemicals in the synapse?
in his experiment with two frog's heart, stimulating one nerve released something that inhibited heart rate, and stimulating a different nerve released something that increased heart rate. he knew that he was collecting and transferring chemicals not loose electricity. therefore, loewi concluded, nerves send messages by releasing chemicals
What does the reticular formation control?
is one means by which pain signals from the lower body reach the cerebral cortex. It is also the origin of the descending analgesic pathways. The nerve fibers in these pathways act in the spinal cord to block the transmission of some pain signals to the brain.
What is the all or none law?
is that the amplitude and velocity of an action potential are independent of the intensity of the stimulus that initiated it, provided that the stimulus reaches the threshold Analogy: flushing a toilet. You have to make a press of at least a certain strenght (threshold) but pressing it faster does not make the toilet flush any faster
What are the 2 types of strokes and how are they treated?
ischemia (most common): the result of blood clot or other obstruction in an artery hemorrhage (less common): the result of ruptured artery tissue plasminogen activator (tPA) breaks up blood clots. this works great for ischemia but not for hemorrhage. so a MRI is used to distinguished between them two but it could take a long time and time is limited since tPA is giving within 4 hours of the stroke. therefore most physician give it anyways because theres a higher chance of ischemia and low cases of hemorrhage
What does the spinal cord communicate with?
it communicates with all the sense organs and muscles except those of the head.
What is phantom limb and how does it work?
most people with an amputation experience this, it's a continue sensation of amputated body part. it can last for week. months or even a lifetime the brain areas that start off as arm areas, hand areas or whatever pain retain those properties even after decades without normal input. phantom libs develop when the relevant portion f the somatosensory cortex reorganizes and becomes response to alternative inputs.
Where do the building blocks for synthesizing neurotransmitters come from?
neuron synthesize nearly all neurotransmitters form amino acids, which the body obtains form protein in the diet
Know about everything about neurogenesis and apoptosis.
neurons starts life with a suicide program if its axon does not make contact with apporite postsynaptic cell by certain age, the neuron kills itself through a proccess call apoptosis the neurotropin promotes the survival of the neuron so they wont "commit suicide"
2 main types of neural cells
neurons which process information and glia which provide the neurons with mechanical and metabolic support
How much alcohol can a pregnant woman drink safely and what happens to the baby's brain if she drinks too much?
none at all because moderate drinking can produce measurable effects if she drinks too much during pregnancy the children are born with fetal alcohol syndrome, a condition marked by hyperactivity, impulsiveness, difficulty maintaining attention and varying degrees of mental retardation
Know all the parts of the neuron and their functions.
nucleus: The process protein synthesis begins in the nucleus dendrites: receive chemical messages from other neurons. axon: transmit an electro-chemical signal to other neurons. myelin sheath: a series of fatty cells which have wrapped around an axon synapses: Between the axon ending and the dendrite of the next neuron is a very tiny gap called the synapse (o cell body: contains the nucleus of the cell and its associated intracellular structures. axon ending: It is there that the electro-chemical signal that has travelled the length of the axon is converted into a chemical message that travels to the next neuron.
Know the 4 types of biological explanations
physiological: relates behavior to the activity of the brain and other organs. ex: chemical reaction that enable hormones to influence brain ontogenetic: describes how a structure or behavior develops, including the influence of genes, nutrition, experiences, and their interactions ex: maturation of frontal parts of the brain evolutionary:reconstruct the evolutionary history of a structure or behavior; they call attention to behavioral similarities among related species ex: bat wings are modified arms functional:why a structure or behavior evolved as it is ex:a functional explanation identifies the advantage of being evolve as it is
Know everything about migration, proliferation, differentiation, synaptogenesis, and myelination
proliferation: productions of new cells migration: the primitive neurons being to migrate( move) some do it faster than others and the slower ones reach their destination until adulthood differentiation: at first, a primitive neuron looks like any other cell but in this state the neuron forms axons and dendrites myelination: the process by which glia produce the insulating fatty sheaths that accelerate transmission in may vertebrate axons synaptogenesis: final stage; the formation of synapses. even though it starts before birth, it continuous throughout life with neurons forming new synapses and discarding the old ones
What is the binding problem?
question of how various brain areas produce perception of a single object We don't know how the brain manages to combine the multiple stimuli into a single percept. ex: Sensations of color, shape, boundary and texture are combined to produce the percept of a person's face. ex:When you see windows, a door, a garage, and a roof as a house.
What is reuptake and how does it work?
reabsorption of a neurotransmitter by the presynaptic terminal after it has performed its function of transmitting a neural impulse.; it occurs through special membrane proteins called transporters
Know the function of stem cells in neural development
stem cell: are undifferentiated biological cells that can differentiate into specialized cells and can divide (through mitosis) to produce more stem cells. Stem cells afford the plasticity to generate, repair, and change nervous system function.
When axons are damaged or severed, how do other nearby axons respond?
strokes, damaged to the brain, head injury a surviving axon grows a new branch to replace the synapses left vacant by a damaged axon
What are the functions of the sympathetic and parasympathetic nervous system?
sympathetic: prepare the organs for vigorous activity; flight or fight ex: heat rate increases parasympathetic: facilitates vegetative nonemergency responses ; opposite of the sympathetic ex: heart rate decreases
How does the brain protect itself from viruses and poisons?
the blood brain barrier stops viruses and important nutrients from entering the brain
Know about neurotropins and their role in apoptosis.
the nerve growth factor is a neurotropins, meaning a chemical that promotes the survival and activity of neurons apoptosis is a programmed mechanism of cell death. NGF cancels the program for apoptosis; i is the postsynaptic cell's way of telling the incoming axon ill
How the chemicals that cannot flow freely across the cell, enter the neuron?
through a specialized protein channel using active transport (energy) chemicals that are actively transported are glucose (brain's main fuel) , amino acids (building blocks of proteins) , purines, choline, a few vitamins, iron and certain hormones
How are myelinated and myelinated action potentials different?
transmission in myelinated axons is faster than unmyelinated because because the myelin insulates the membrane, which allows the longitudinal electrotonic current to flow farther in the cytoplasm
Know about excitatory postsynaptic potentials and inhibitory postsynaptic potentials.
unlike action potentials, which are always depolarizations, graded potentials may be either depolarizations (excitatory or hyperpolarizations (inhibitory) excitatory postsynaptic potential: a graded depolarization. it results from a flow of sodium ions into the neuron. if EPSP does not cause the cel to reach its threshold, the depolarization decays quickly inhibitory postsynaptic potential: resembles EPSP. An IPSP occur when synaptic input selectively opens the gates for potassium ions to leave the cell ( carrying a positive charge with them) or for chloride ions to enter the cell ( carrying a negative charge)
