Unit 3 - Biopsychology

What does a gene do?

code for specific proteins

How many kinds of protein molecules is the human body constructed of?

70,000

What are the 4 nucleotides?

adenine, thymine, cytosine, guanine

What does DNA stand for?

deoxyribonucleic acid

What are bases of DNA?

long sequences of the nucleotides that provide the blueprint for genetic inheritance

What are genes?

vertical sequences of DNA

What are alleles?

alternate forms of genes

What happens when proteins combine with other bodily products and the environment?

increases the probability of a given behavior or attribute

What are epigenetics?

field which explores how gene expression is influenced by environmental events (experiences, nutrition, stress) and even passed on to successive generations

What are genes arranged on?

chromosomes

How many chromosomes do humans have?

46 chromosomes, arranged in 23 pairs

What are the first 22 pairs of chromosomes called?

autosomes (homologous chromosomes)

What are homologous chromosomes?

the two members of each pair are similar in size, shape, and genetic function

What is the 23rd pair of chromosomes called?

sex chromosome (X or Y)

What are the female sex chromosomes?

XX

What are the male sex chromosomes?

XY

How many chromosomes do sperm and ova have?

½ the normal pair

What is genotype?

total genetic endowment inherited by an individual

What is phenotype?

observable and measurable characteristics and traits of an individual

What is phenotype a product of?

the interaction of the genotype and the environment

What is range of reaction?

genes provide our possibilities (the limits); the environment sets our actualities

What are homozygous alleles?

alleles that are alike

What are heterozygous alleles?

alleles that are not alike

What is a dominant allele?

allele whose characteristics are reflected in the phenotype even when part of a heterozygous genotype

What are examples of dominant alleles?

tongue rolling, Huntington’s disease

What is a recessive allele?

allele whose characteristics do not tend to be expressed when part of a heterozygous genotype

What are examples of recessive alleles?

sickle-cell anemia, PKU (phenylketonuria)

What is sickle-cell anemia?

recessive allele; changes the shape of red blood cells

What is PKU (phenylketonuria)?

recessive allele; unable to break down phenylalanine (amino acid found in milk and foods high in protein)

What are codominant alleles?

condition in which individual, unblended characteristics of two alleles are reflected in the phenotype

What are examples of codominant alleles?

AB blood type

What alleles are in blood type?

A, B, O

What blood type alleles are dominant?

A, B

What blood type alleles are recessive?

O

What are polygenic characteristics?

phenotype characteristic influenced by two or more genes

What are examples of polygenic characteristics?

skin color, height, reactiveness

What is important about sex-linked disorders?

the Y chromosome does not have a corresponding allele, so if the male inherits a recessive allele on the mother’s X chromosome, the effects will be apparent

What are examples of sex-linked disorders?

hemophilia, red-green color blindness, baldness

What is the nervous system?

a highly complex communication system of cells that function to coordinate and direct an organism in its interactions with its environment

What are neurons?

specialized cells which receive information and transmit it to other cells by conducting electrochemical impulses

What is the basic unit of the nervous system?

neurons

Approximately how many neurons does the adult human brain have?

100 - 200 billion (closer to 80 billion)

What is a nerve?

a bundle of axons (either sensory or motor) existing outside the CNS

What are the types of neurons?

sensory, motor, interneuron

What is a sensory neuron?

carry information from sensory organs to the central nervous system

What is a motor neuron?

receives excitation from other neurons and conducts impulses from soma in spinal cord to muscle or gland cells

What is an interneuron?

can receive information from sensory neurons and can send it to motor neurons or other interneurons

Where are interneurons located?

between sensory and motor neurons

What are most of the neurons in the human nervous system?

interneurons

What is the cell body or soma?

structure of the cell that contains the nucleus; much of cellular metabolism occurs in the soma

What is the dendrite?

thin, widely branching fiber that emanates from a neuron; receives information

What is the axon?

single fiber extending from a neuron; sends information

What is the axon hillock?

a swelling of the soma, at the point which the axon begins; beginning of the action potential

What is the myelin sheath?

a fatty material that insulates neurons; speeds up action potential

How much faster is a myelinated neuron versus an unmyelinated neuron?

10 times faster

What are the nodes of Ranvier?

short, unmyelinated sections of axon between myelin; area of myelinated axon at which the action potential occurs

What are the terminal buttons?

the swellings at the tip of an axon; the point from which neurotransmitters are released

What are terminal buttons also known as?

axon terminal; end buttons

What is electrical communication?

communication WITHIN the neuron; how information travels between dendrites to the terminal buttons

What is resting potential?

the resting state of the neuron

What happens during resting potential?

the inside of the neuron is more negative than the outside of the neuron due to the difference in concentration of ions

What ions are part of resting potential?

sodium (Na+) and potassium (K+)

Where does the threshold of excitation occur?

at the axon hillock

What is the threshold of excitation?

the excitatory and inhibitory changes in the membrane of the dendrites and soma are “added” together, and if the electrical charge at the axon hillock is high enough to reach the minimum level needed to start an action potential, the ion channels will open

What is action potential?

the movement of ions down the axon of a neuron; the depolarization of the axon

What is the “all-or-nothing” principal?

action potentials either occur or do not occur; it does not become stronger or weaker with time/repetition

What is chemical communication?

communication BETWEEN neurons (or other cells)

What is the synapse?

point of communication between two neurons or between a neuron and a muscle

Where is the synapse?

the space between neurons

What is an excitatory synapse?

neurotransmitter makes it more likely for positive ions (Na+) to move into the neuron

What is an inhibitory synapse?

neurotransmitter makes it more likely for negative ions (Cl-) to move into the neuron or for positive ions (K+) to move out of the neuron

What is a neurotransmitter?

chemical released at a synapse

What are receptor sites?

areas of a neuron that have protein embedded into the membrane

What happens at receptor sites?

when a neurotransmitter attaches to the active site of a receptor, it can directly open a channel or it can have slower, more long term effects

What does “lock and key” mean?

the neurotransmitter (key) has a specific shape that fits exactly into the receptor site (lock); only if there is a perfect fit between the neurotransmitter and the receptor site will the membrane of the receiving cell be altered

What are the steps at the synapse?

1. the neuron synthesizes neurotransmitters

2. the neuron transports these neurotransmitters to the axon terminals

3. an action potential causes the release of the neurotransmitters from the terminal buttons

4. the released molecules attach to receptors on the receiving cell and alter its activity

5. the molecules separate from their receptors and (in some cases) are converted into inactive chemicals

6. in some cells, as many as possible of the neurotransmitters are reabsorbed and recycled

What are the steps to neural communication?

1. a neuron receives stimulation at the receptor sites on its dendrites or cell body

   1. this makes Na+ channels either more likely (excitatory) or less likely (inhibitory) to open

2. if there is enough positive charge to reach threshold at the axon hillock, an action potential is started

   1. the action potential flows down the entire axon

   2. at the axon terminal buttons, the action potential causes vesicles of neurotransmitters to bind to the cell membrane

3. the vesicles open, releasing neurotransmitters into the synapse

   1. the neurotransmitters cross the synapse and bind onto receptor sites on the receiving cell

   2. if the neurotransmitters are excitatory, Na+ channels open, increasing the positive charge; if they are inhibitory, it is less likely the channels will open

4. the receiving neuron adds up the charges at its own axon hillock; if it reaches threshold, an action potential occurs

5. the process repeats

What are the major neurotransmitters?

dopamine, serotonin, norepinephrine/adrenaline, acetylcholine, gaba, glutamate, endorphins

What is dopamine?

pleasure transmitter; stimulant

What is serotonin?

mood transmitter; hallucinogen

What is norepinephrine/adrenaline?

fight-or-flight neurotransmitter; stimulant

What is acetylcholine?

learning neurotransmitter; stimulant

What is GABA?

calming neurotransmitter; depressant

What is glutamate?

memory neurotransmitter; mild hallucinogen and depressant

What are endorphins?

euphoria neurotransmitter; depressant

What are the two main divisions of the nervous system?

central nervous system (CNS) and peripheral nervous system (PNS)

What makes up the CNS?

the brain and spinal cord

What makes up the PNS?

nerves outside the brain and spinal cord

What are the two main divisions of the PNS?

skeletal (somatic) NS and autonomic NS

What is the skeletal (somatic) NS?

nerves that carry sensory information to the CNS and motor information from the CNS muscles

What is the VOLUNTARY nervous system?

skeletal (somatic) NS

What is the autonomic NS?

nerves that regulate the internal organs

What is the INVOLUNTARY nervous system?

autonomic NS

What are the two main division of the autonomic NS?

sympathetic NS and parasympathetic NS

What is the sympathetic NS?

nerves that activate the internal organs for vigorous activity

What is “fight-or-flight” associated with?

the sympathetic NS

What happens during “fight-or-flight?”

increased heartbeat, blood pressure, respiration rate, sweating, diverts blood from internal processes such as digestion to the extremities; leading to an increased ability to fend off or run away from danger

What is the parasympathetic NS?

nerves innervating the internal organs; tend to conserve energy

What is “day-to-day housekeeping” associated with?

the parasympathetic NS

What happens during “day-to-day housekeeping?”

decreased heartbeat, blood pressure, respiration rate, sweating, directs blood to internal processes such as digestion