chapter 2: biology and psychology Flashcards
neurons are
neurons are specialized cells of the nervous system that conduct impulses. they send messages. vary according to function and location
what does the nucleus use and what does it produce
the nucleus of a neuron uses oxygen and nutrients to generate the energy needed to carry out the work of the cell.
glial cells
- Remove dead neurons and waste products
– Nourish and insulate neurons
– Form myelin and play a role in neural
transmission of messages
– Increase with the development of the nervous
system
neurons include
Include a cell body, an axon, and
dendrites, myelin
myelin
- Fat that insulates the axon from electrically
charged atoms, or ions
– Minimizes leakage of the electrical current
what do dendrites do
dendrites in a neuron receive incoming messages from other neurons.
the passage of messages through neuron until axon terminal
the messages enter the neuron through the dendrite and are passed through the axon, sent from the axon terminal.
where do neurotransmitters come from
neurotransmitters are released from the axon terminal.
what happens as kids get older
as a child matures, the axons become longer and dendrites and terminals proliferate. the number of glial cells increases.
myelination
myelination is a part of the maturation process. this allows infants to engage in visual-motor coordination and other activities untill this process reaches a level.
multiple sclerosis
multiple sclerosis, myelin is replaced with a hard fibrous tissue that throws off the timing of nerve impulses and disrupts muscular control.
afferent neurons (sensory neurons)
receptors or sensory neurons that are near the surface of the skin.Transmit messages from sensory receptors to the spinal cord and brain
efferent neurons (motor neurons)
transmit messages from the brain/spinal cord to muscles and glands. Transmit messages from the brain or spinal cord to muscles and glands
luigi galvani (1737–1798))
conducted an experiemnt in a rainstorm with frogs and wires. he was able to demonstrate the message - neural impulses - that travel along neurons are ELECTROCHEMICAL in nature
neural impulses
- Electrochemical messages that travel
within neurons - Neurons contain negatively or positively
charged ions - Difference in electrical charge polarizes a
neuron for firing
– Firing: Conduction of neural impulse along a
neuron
polarization
to ready a neuron for firing by creating an internal negative charge in relation to the body fluid outside the cell membrane.
resting potential
the electrical potential across the neural membrane when is it not responding to other neurons
depolarized (positively charged)
to reduce the resting potential of a cell membrane from about 70 millivolts toward zero.
depolarization
when area on the resting neuron is stimulated
action potential
the electrical impulse that provides the basis for the conduction of a neural impulse along an axon of a neuron
neural impulse as it progesses
the strength does not change because it is being created anew as it progresses.
all-or-none principle
the fact that a neuron fires an impulse of the same strength whenever its action potential is triggered
threshold
strength of the incoming messages required by a neuron to fire
refractory period
a phase following firing during which a neuron is less sensitive to messages from other neurons and will not fire. “recovery” time
synapse
a junction between the axon terminals of one neuron and the dendrites or cell body of another neuron
synaptic cleft
fluid-filled gap between the axon terminal and dendrite
neurotransmitters
Chemical substances
* Present in the synaptic vesicles of axon
terminals
* Have unique chemical structures and fit
into specific receptor sites
– Loose neurotransmitters are either broken
down or reabsorbed by the axon terminal
(reuptake)
Excitatory and inhibitory functions
determine whether a neuron will fire
– Excite: Cause other neurons to fire
– Inhibit: Prevent other neurons from firing
* Involved in physical processes and
psychological processes
* Excess or deficiency is linked to
psychological disorders
receptor sites
Loose neurotransmitters are either broken
down or reabsorbed by the axon terminal
(reuptake)
excite and inhibit
Excite: cause other neurons to fire
inhibit: prevent other neurons from firing
types of neurotransmitters
Acetylcholine
Dopamine
Norepinephrine
Serotonin
Gamma-aminobutyric acid
Endorphins
effects of Acetylcholine (ACh)
Controls muscle contractions
– Affected by curare and botulism
* Cause paralysis
– Prevalent in the hippocampus
– Decrease of ACh in the brain impairs memory
formation
The effects of dopamine
- Affects the ability
to perceive
pleasure, voluntary
movement, and
learning and
memory
– Deficiencies are
linked to
Parkinson’s
disease
effects of norepinephrine
Excitatory neurotransmitter that increases heart rate
– Involved in general arousal, learning and memory, and
eating
– Excesses and deficiencies are linked to mood
disorders and impairment in memory formation
effects of serotonin
Involved in emotional arousal and sleep
– Deficiencies are linked to eating disorders,
alcoholism, depression, aggression, and insomnia
effects of Gamma-aminobutyric acid (GABA)
Inhibitory neurotransmitter that may help calm
anxiety reactions
– Deficiency is linked to depression
effects of endorphins
- Inhibit pain and increase sense of competence
– Enhance the functioning of the immune system
– Connected to the pleasurable runner’s high
– Similar to the narcotic morphine
branches of peripheral nervous system
somatic nervous system
autonomic nervous system
somatic nervous system
Messages received from the brain and spinal cord control purposeful body movements
Autonomic nervous system
– Regulates the glands and muscles of internal
organs
* Sympathetic and parasympathetic divisions
have largely opposing effects
– Effects can be averaged out to some degree when
stimulated simultaneously
central nervous system
spinal cord, brain
spinal cord
Transmits messages from sensory receptors
to the brain and from the brain to muscles and
glands
– Spinal reflex
* Involves only a sensory neuron and a motor
neuron in most instances
* Neural impulse is transmitted by interneurons from
the sensory neuron through the spinal cord to the
motor neuron in some reflexes
Spinal cord and brain contain gray matter
and white matter
gray matter
consists of non-myelinated neurons
white matter
consists of myelinated axons
experimenting with the brain
- allows us to asses damage from disease and accidents
– includes Intentionally damaging parts of the brain in
animals
– we use electrical probes to stimulate parts of the
brain
Electroencephalograph (EEG)
- Helps record the natural electrical activity of the
brain
– Detects brain waves that pass between the
electrodes
how is research done on the brain
- by experimenting with the brain
- electroencephalograph (EEG)
- Brain imaging techniques
Brain imaging techniques
– Computerized axial tomography (CAT or
CT scan)
– Positron emission tomography (PET scan)
– Magnetic resonance imaging (MRI)
– Functional MRI (fMRI)
structures and functions of the brain: hindbrain
Hindbrain
– Medulla
– Pons
– Cerebellum
* Reticular formation
– Lower part is within the hindbrain
* Sends messages to the cerebral cortex when
stimulated
* Makes one alert to sensory information
struzctures and functions of the brain: forebrain
– Thalamus: Relay station for sensory
stimulation
– Hypothalamus: Regulates body temperature,
concentration of fluid, storage of nutrients,
motivation, and emotion
* Involved in hunger, thirst, sexual behavior, caring for
offspring, and aggression
– Limbic system
* Amygdala: Connected with aggression, fear,
vigilance, emotions, learning, and memory
structures and functions of the brain: cerebrum
Cerebrum: Responsible for thinking and
language
– Cerebral cortex: Surface of the cerebrum
* Wrinkled or convoluted with ridges and valleys
(fissures)
* Connected with cognitive abilities
– Corpus callosum
* Connects the two hemispheres of the cerebrum
created by fissures
the cerebral cortex
Outer layer of the cerebrum
* Involved in bodily activities, sensations,
and perceptions
* Hemispheres – Left and right lobes
– Occipital lobe deals with vision
– Temporal lobe deals with hearing and auditory
functions
– Parietal lobe contains the somatosensory
cortex
– Frontal lobe contains the motor cortex
how thinking and language relate to the cerebral cortex
Association areas
– Not primarily involved in sensation or motor
activity
– Responsible for learning, thought, memory,
and language
* Association areas in the frontal lobe
– Responsible for executive functions
– Retrieves visual, auditory, and other
memories and manipulates them
Language functions
- Brain hemispheres mirror and differ in
function
– Left hemisphere contains language functions
for nearly all right-handed people
– If damaged before the age of 13, speech
functions can transfer to the right hemisphere
* Key language areas
– Broca’s area and Wernicke’s area
* Damage in either causes aphasia
Wernicke’s area
– Lies in the temporal lobe
– Wernicke’s aphasia: Impairs the ability to
comprehend speech and to think of words to
express one’s thoughts
* Angular gyrus
– Translates visual information into auditory
information
– Damages reading ability
Broca’s area
– Located in the frontal lobe
– Influences speech
– Broca’s aphasia: One is able to understand
language but speaks slowly and laboriously
left brained or right brained
- Left-brained individuals would be logical
and intellectual - Right-brained individuals would be
intuitive, creative, and emotional - Hemispheres do not act independently
– Functions overlap and they respond
simultaneously
handedness
- Left-handed
– Have greater-than-average probability of
language problems and certain health
problems
– More likely than right-handed people to be
gifted artists, musicians, and mathematicians - Origins of handedness may be genetic
– Being left-handed was once seen as a
deficiency - Heritability makes about a 24%
contribution to the likelihood of being right-
or left-handed
split brain experiments
- People with severe cases of epilepsy may
require split-brain operations - Similar to having two brains
– Caused by the inability of one hemisphere to
communicate with the other
the endocrine system
Comprises ductless glands that release
hormones into the bloodstream
– Hormones
* Regulate growth, metabolism, and some behaviors
* Maintain steady bodily states
* Negative feedback loop – Gland is signaled to stop
when the right amount of a hormone has been
secreted
pituitary gland
- Lies below the hypothalamus
- Labeled as the master gland
- Secretes hormones that regulate the
functioning of other glands
– Growth hormone, prolactin, vasopressin, and
oxytocin - Hypothalamus regulates pituitary activity
pineal gland
Secretes melatonin that:
– Regulates sleep-wake cycle
– May affect the onset of puberty
– Connected with aging
– Acts as a mild sedative
thyroid gland
Produces thyroxin that affects the body’s
metabolism
– Variation in levels can lead to:
* Hypothyroidism
* Hyperthyroidism
* Cretinism
ardenal glands
- Located above the kidneys
- Comprise an outer layer (cortex) and an
inner core (medulla) - Cortical steroids (corticosteroids)
– Secreted by the adrenal cortex - Adrenal medulla secretes epinephrine and
norepinephrine
– Epinephrine has emotional and physical
effects
testes and ovaries
- Testosterone
– Produced by the testes (produced in small
amounts by the adrenal gland)
– Enables development of male sex
characteristics - Estrogen and progesterone
– Produced by the ovaries along with small
amounts of testosterone
Steroids
– Increase muscle mass
– Heighten resistance to stress
– Increase the body’s energy supply
Anabolic steroids
- Enhance athletic prowess
– Outlawed in sports
– Connected with self-confidence and
aggressiveness
darwins theory of evolution
- Struggle for existence
– Competition for same resources
– Prosperity or extinction of a species is
determined by natural selection - Natural variations and mutations lead to
differences among individuals
– Affect one’s ability to adapt to change
Evolutionary Psychology
- Studies the ways in which adaptation and
natural selection are connected with
mental processes and behavior - Behavior patterns evolve and can be
transmitted genetically from generation to
generation
– Behavior patterns are called instinctive or
species-specific behaviors - Instinct
– Stereotyped patterns of behavior that are
triggered in a specific situation
– Species-specific - Resists modification or results in punishment
Heredity
Biological transmission of traits from parent to
offspring through genes
Genetics
– Subfield of biology that studies heredity
* Behavioral genetics: Focuses on the contributions
of genes to behavior
Gene
– Basic unit of heredity
– Regulates the development of specific traits
Chromosomes
– Made up of strings of genes
– Humans have 46 chromosomes (23 pairs)
* Formed by DNA (deoxyribonucleic acid)
– Double helix: Contains the genetic code
- One receives 23 chromosomes from each
parent - 23rd pair of chromosomes are sex
chromosomes
– XX – Female
– XY – Male
genes and chromosomes
- Human Genome Project
– Sequencing of DNA consists of about three
billion DNA sequences spread throughout
one’s chromosomes - Extent of influence of genes on complex psychological traits are debated
- Some traits are determined by a single
pair of genes
– Other traits are polygenic
genotype
– Individual’s genetic makeup (nature)
phenotype
Actual appearance, based on genotype and
environmental influences (nature and
nurture)
down syndrome
Caused by chromosomal abnormality
kinship studies
- Focus on the presence of traits and
behavior patterns in people who are or are
not related biologically - Twin studies
– Compare the presence of traits and behavior
patterns in monozygotic twins, dizygotic
twins, and other people - To determine the role of genetic factors
– Show the strong influence of genetic factors
on physical features - Adoption studies
– Psychologists look for similarities between
children and their adoptive and natural
parents
summary
- The nervous system regulates the body
through neurons that transmit information - Peripheral nervous system transmits
messages to and from the central nervous
system - The hindbrain includes the medulla, pons,
and cerebellum - The forebrain includes the thalamus,
hypothalamus, limbic system, and cerebrum - Parts of the cerebral cortex are involved in
bodily activities, thinking, and problem
solving - Glands of the endocrine system secretes
hormones that affect behavior and mental
processes - Evolutionary psychology studies the concept
of adaptation and natural selection
