Biology and Psychology – Brandon Skenandore
What are some of the basic concepts of the theory of evolution?
Struggle for existence, natural selection determines the species that prosper and those that fade away
Mutations: random genetic variations that lead to differences among individuals in physical traits, individuals whose traits are better adapted to environment are more likely to survive (or, be “naturally selected”)
Concepts of adaptation and natural selection have been applied to psychological traits, and are key concepts in evolutionary psychology
What is evolutionary psychology?
Studies the ways in which adaptation and natural selection are connected w/ mental processes and behavior
Not only physical traits but also patterns of behavior evolve and are transmitted genetically from generation to generation
Behavior patterns are termed instinctive or species-specific because they evolve within certain species.
What is meant by an “instinct”?
A stereotyped pattern of behavior that is triggered in a specific situation. Nearly identical among the members of the species in which it appears
Tends to resist modification, even when it serves no purpose or results in punishment
What is meant by “heredity”?
Defines one’s nature – which is based on one’s biological structures and processes
What is meant by “genetics”?
Subfield of biology that studies heredity
Behavioral genetics bridges the sciences of psychology and biology.
Concerned with the genetic transmission of traits that give rise to patterns of behavior.
Molecular genetics attempts to identify specific genes that are connected w/ behavior and mental processes.
What are the roles of genes and chromosomes in heredity?
Genes are most basic building blocks of heredity
They regulate development of specific traits
Chromosomes are made up of strings of genes
Each cell in the body contains 46 chromosomes arranged in 23 pairs
Chromosomes are large complex molecules of DNA (deoxyribonucleic acid)
3 billion DNA sequences throughout chromosomes, these sequences (A,T, C, G) make you grow the way you do
Polygenic traits are influenced by combinations of genes
Genotype provided by genetic code, full genetic potential as determined by the sequencing of chemicals in DNA (acquire language)
Phenotype is the manner in which genetic code manifests itself because of your experiences and environmental circumstances (what language you speak)
Nature (heredity) and Nurture (environmental influences)
Sex Chromosomes determine whether we are female or male, 23rd pair of chromosomes
Down Syndrome occurs when people do not have the normal number of 46 chromosomes (23 pairs), most have an extra chromosome on the 21st pair
What are kinship studies?
Ways in which psychologists compare presence of traits and behavior patterns in people biologically related or unrelated
Monozygotic (MZ) twins identical, when fertilized cell (zygote) divides and separates, develops two people w/ same genetic makeup
Dizygotic (DZ) twins share 50% of genes
What is selective breeding?
Selection by humans instead of nature
Breed plants and animals to enhance desired physical and behavioral traits, breed cattle and chickens to be bigger and fatter for more meat
What are neurons?
Cells that can be visualized as having branches, trunks, and roots, we are born with over 100 billion neurons
Different functions, center stage of nervous system
Glial cells remove dead neurons and waste products from the nervous system, nourish and insulate neurons, and direct their growth
Dendrites extend like roots from cell body, receive incoming messages
Each neuron has an axon that extends like a trunk from the cell body, very thin, but those that carry messages from toes to spinal cord extend several feet axons are wrapped tightly with white, fatty myelin, makes them look like strings of sausages under microscope
Afferent neurons: neurons that transmit messages from sensory receptors to the spinal cord and brain
Efferent neurons: neurons that transmit messages from the brain or spinal cord to muscles and glands
What are neural impulses?
The electrochemical discharge of a nerve cell, or neuron
Difference in electrical charge polarizes the neuron with a negative resting potential (electrical potential across the neural membrane when it is not responding to other neurons)
When area on the surface of resting neuron is stimulated by other neurons, cell membrane in the area changes permeability to allow positively charge sodium ions to enter, area of entry becomes positively charged, or depolarized.
Action potential: electrical impulse that provides the basis for the conduction of a neural impulse along an axon of a neuron
What happens when a neuron fires?
All-or-none principle: either a neuron fires or it doesn’t
Refractory period: time of recovery when sodium is prevented from passing through the neuronal membrane.
What is a synapse?
A junction between the axon terminals of one neuron and the dendrites or cell body of another neuron
Which neurotransmitters are of interest to psychologists? What do they do?
The chemical keys to communication into the synaptic cleft, influence the receiving neuron
Fits into specifically tailored harbor, or receptor site
Acetylcholine (ACh) controls muscle contractions
Prevalent in part of brain called the hippocampus, (structure involved in formation of memories)
Dopamine is involved at the level of the brain and affects voluntary movements, learning and memory, and emotional arousal
Deficiencies are linked to Parkinson’s disease
Norepinephrine accelerates the heart rate, affects eating, and is linked with activity levels, learning, and remembering
Serotonin is involved in behavior patterns and psychological problems, including obesity, depression, insomnia, alcoholism, and aggression
Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter that may lessen anxiety
Endorphins inhibit pain by locking pain-causing chemicals out of their receptor sites
What are the parts of the nervous system?
Consists of the brain, spinal cord, and nerves (bundle of axons from many neurons) linking them to the sensory organs, muscles, and glands
Central Nervous System consists of brain and spinal cord
Peripheral Nervous System is made up of the afferent and efferent neurons
What are the divisions and functions of the peripheral nervous system?
Consists of sensory and motor neurons that transmit messages to and from the central nervous system.
Somatic Nervous System: division of peripheral nervous system, connects the central nervous system with sensory receptors, skeletal muscles, and the surface of the body
Autonomic nervous system (ANS): Division of the peripheral nervous system that regulates glands and activities such as heartbeat, respeiration, digestion, and dilation of the pupils
Sympathetic branch: most active during emotional responses, fear, anxiety, spend the body’s reserves of energy
Parasympathetic branch: most active during digestion and others that restores the body’s reserves of energy
What are the divisions and functions of the central nervous system?
Spinal cord: “information superhighway”, capable of “local government”, controls some responses to external stimulation through spinal reflexes (unlearned response to a stimulus that may involve only two neurons), sometimes there is a third neuron, or interneuron, transmits the neural impulse from the sensory neuron through spinal cord to motor neuron.
Spinal cord consists of gray matter (nonmyelinated neurons, spinal reflexes), and white matter (longer, nyelinated axons, carry messages to and from the brain)
How do researchers learn about the functions of the brain?
Test rats with lesions (injury that results in impaired behavior or loss of function)
What are the structures and functions of the brain?
Medulla: oblong area of hindbrain, regulates heartbeat nd respiration
Pons: structure of the hindbrain involved in respiration, attention, and sleep and dreaming
Cerebellum: part of hindbrain, involved in muscle coordination and balance
Reticular activating system (RAS): involved in attention, sleep, and arousal
Thalamus: area near center of brain, involved in relay of sensory information to the cortex, functions of sleep and attention
Limbic system: group of structures, involved in memory, motivation, emotion that forms a fringe along the inner edge of the cerebrum
Amygdale: part of the limbic system, apparently facilitates stereotypical aggressive responses
Cerebrum: large mass of forebrain, consists of two hemispheres
Cerebral cortex: wrinkled surface area (gray matter) of the cerebrum
Corpus callosum: a thick fiber bundle that connects the hemispheres of the cortex
What are the parts of the cerebral cortex?
Frontal lobe: lies to front of the central fissure
Parietal lobe: lies just behind the central fissure
Tempral lobe: lies below the lateral fissure, near the temples of the head
Occipital lobe: lies behind and below the parietal lobe and behind the temporal lobe
Somatosensory cortex: section of cortex, sensory stimulation is projected, lies just behind the central fissure in parietal lobe
Motor cortes: section of cortex, lies in frontal lobe, across the central fissure from sensory cortex. Neural impulses in motor cortex are linked to muscular responses throughout the body
What parts of the cerebral cortex are involved in thinking and language?
Prefrontal region of the brain
Broca’s area, Wernicke’s area, damage to either likely to cause an aphasia (disruption of ability to understand or produce language)
Wernicke’s aphasia: characterized by difficulty comprehending the meaning of spoken language
Broca’s aphasia: language disorder characterized by slow, laborious speech
What would it mean to be “left-brained” or “right-brained”?
Hardly any evidence, functions overlap
Does it matter whether one is left-handed? Why are people right-handed or left-handed?
Left-handedness linked to language problems and health problems, but more artistic and mathematic.
What happens when the brain is split in two?
Epilepsy (temporary disturbances of brain functions, involve sudden neural discharges) sometime fixed with split-brain operations, corpus callosum severed, different sides of brain act independently.
What is the endocrine system?
The body’s system of ductless glands, secrete hormones ( substance secreted by endocrine, regulates various body functions) and release them directly into the bloodstream
Some hormones influence only the pituitary gland (secretes growth hormone, prolactin, antidiuretic hormone, and other hormones)
Growth hormone: pituitary hormone, regulates growth
Prolactin: pituitary hormone, regulates production of milk and maternal behavior (in animals)
Antidiuretic hormone (ADH) conserves body fluids by increasing reabsorption of urine, connected w/ paternal behavior on mammals
Oxytocin: stimulates labor, lactation
Malatonin: pineal hormone, regulates sleep-wake cycle, onset of puberty
Thyroxin: thyroid hormone, increases metabolic rate
Corticosteroids: steroids produced by adrenal cortex, regulates carbohydrate metabolism, increase resistance to stress by fighting inflammation and allergic reactions
Epinephrine: stimulates sympathetic ANS activity
Testosterone: male sex hormone, promotes growth of male sexual characteristics
Estrogen: several female sex hormones
Progesterone: female sex hormones, growth of organs and maintains pregnancy