Unit 3 - Biological Basis of Behavior

Why are psychologists concerned with human biology?

Why are psychologists concerned with human biology?

By looking at the biological basis of behavior, psychologists are able to understand how people think, act & feel.

What do biological psychologists do?

Study the links between human biology & behavior/mental processes.

Neuron

Nerve cell that is the basic building block of the nervous system.

What is the cell body also known as

soma

Cell body (soma)

Part of neuron that contains the nucleus.

nucleus = cell’s life support center

Dendrite

Bushy branching extensions that recieve & integrate messages conducting impulses towards the soma

Axon

attached to the soma, the neuron extention that passes messages to other neurons, muscles, or glands.

Myelin sheath

Fatty tissue layer segmentally encasing axons of some neurons; increases transmission speed & provides insulation.

Schwann cell

produces myelin

How are neural impulses generated?

If all the recieved chemical signals exceed a minimum threshold, the neuron fires, transmitting an electrical impulse(action potential) down the axon by chemical to electrical processes.

How does the energy transfer in neural impulses?

Chemical to electrical

Action potential

an electrical impulse neurons generate & conduct along their processes in order to transmit them to the target issues.

Resting potential

the electrical potential difference across the plasma membrane of a cell when the cell is at rest

Refractory period

A period of inactivity after a neuron has fired

Threshold

The level of stimulation required to trigger a neural impulse

Depolarization/repolarization

The wave of depolarization and repolarization is passed along the axon to the terminal buttons, which release neurotransmitters.

All or nonthing response

A Neurons reaction of either firing or not firing

Difference between excitatory and inhibitory neurons

Excitatory, the neurotransmitters cause the neuron on the other side of the synapse to generate an action potential (to fire); other synapses are inhibitory, reducing or preventing neural impulses.

how do neurons communicate

Within the neuron, electrical signals driven by charged particles allow rapid electrical conduction from one end of the cell to the other.

Synapse

Junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Synaptic gap/cleft

gap at the junction between the axon tip

neurotransmitter

Chemical messengers that cross between the synaptic gaps between neurons

Reuptake

Neurotransmitters reabsorption by the sending neuron

Acetylcholine (Ach)

Affects muscle action, learning, and memory

Dopamine

influences movement, learning, attention, and emotion.

Serotonin

Affects mood, hunger, sleep, and arousal

Norepinephrine

helps control alertness and arousal

GABA (Gamma-aminobutyric Acid)

a major inhibitory neurotransmitter that lessens the ability of a nerve cell to receive, create or send chemical messages to other nerve cells.

Endorphins

neurotransmitters linked to pain control and to pleasure

Glutamate

an excitatory neurotransmitter important to maintaining memory, cognition, and mood regulation.

Agonist

A molecule that by binding to a receptor site stimulates a response

Antagonist

A molecule that by binding to receptors site inhibits or blocks a response

Nervous system

the body’s speedy electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous system.

Central nervous system (CNS):

the brain and spinal cord. responsible for decision making

Somatic nervous system

the division of the PNS that controls the body’s skeletal muscles.  Also known as the skeletal nervous system.

Autonomic nervous system

the part of the PNS that controls the glands and the muscles of the internal organs.  Controls the sympathetic and parasympathetic nervous systems.

Sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations. “Flight or flight”

Parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy. “Rest and disgest”

Reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk response.

Sensory neurons

Neurons that carry incoming information from the sensory receptors to the brain and spinal cord

Motor neurons

Neurons that carry outgoing info from the brain and spinal cord to the muscles and glands

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and the motor outputs.

hormones

chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues

Endocrine system

the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.

Adrenal glands

a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinphrine/adrenaline and norepinephrine/noradrenaline) that help arouse the body in times of stress.

 Pituitary gland

the endocrine system’s most influential gland.  Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Thyroid

An important endocrine gland that makes and releases certain hormones. Controls your metabolism

Parathyroid

plays a key role in the regulation of calcium levels in the blood.

Pancreas

exocrine glands that help with digestion and endocrine glands that control blood sugar.

Testis/Ovaries

responsible for producing the sperm and ova, but they also secrete hormones and are considered to be endocrine glands.

Lesion

tissue destruction that is naturally or experimentally caused to help study regions and functions of the brain.

Plasticity:

the brain’s ability to modify itself after tissue damage.

EEG (electroencephalogram):

an amplified recording of the waves of electrical activity that sweep across the brain’s surface. 

CT/CAT (computed tomography):

a series of x-ray photographs of the brain taken from different angles and combined by computer to create an image that represents a slice through the brain.

 PET (positron emission tomography):

measures the different levels of activity in the brain by detecting where a radioactive form of glucose goes while the brain is performing a given task.

MRI (magnetic resonance imaging):

uses magnetic fields and radio waves to produce computer-generated images of different structures within the brain.

fMRI (functional MRI):

a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans.  fMRI scans show brain function.

Brainstem:

the oldest and innermost region of the brain that is responsible for automatic survival functions.  It begins where the spinal cord swells and enters the skull.

 Thalamus:

the brain’s sensory switchboard located on the top of the brainstem.  It directs messages to the sensory receiving areas in the cortex.  It also transmits replies to the cerebellum and medulla.  The sense of smell (olfaction) does not go through the thalamus.

 Medulla:

part of the brainstem that controls heartbeat and breathing.

Reticular Formation:

a nerve network in the brainstem that plays an important role in controlling arousal. 

Cerebellum:

the “little brain” attached to the rear of the brainstem that assists in balance and voluntary movements.

Limbic System:

the doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres that is associated with emotions (such as fear and aggression) and drives (such as those for food and sex). 

Amygdala

two almond-shaped neural clusters in the limbic system that are linked to emotions, especially fear, rage, and aggression.

Hypothalamus

located in the limbic system that lies below (hypo) the thalamus.  It is responsible for the regulation of body maintenance such as eating, drinking, and body temperature.

Hippocampus

the part of the limbic system responsible for memory and learning.

Pituitary gland:

master endocrine gland located in the limbic system

Cerebral cortex/cerebrum

the thin layer of interconnected neural cells that forms a surface layer on the cerebral hemispheres (like bark on a tree).  It is the body’s ultimate control and information processing center.  It is what makes humans upper-level thinking beings as opposed to animals.

Glial cells:

glue cells” in the cortex that guide neural connections, provide nutrients and insulating myelin, and mop up ions and neurotransmitters.

Frontal lobes

the portion of the cerebral cortex that lies just behind the forehead that is involved in speaking, muscle movements, and in making plans and judgments. It also includes the motor cortex.

Motor cortex

the area at the back of the frontal lobes that controls voluntary movements.

Parietal lobes

the portion of the cerebral cortex between the frontal and occipital lobes that is deals with body sensations.  It includes the (somato)sensory cortex.

 (Somato)sensory cortex:

the area at the front of the parietal lobe that registers and processes body sensations.

Occipital lobes

the portion of the cerebral cortex at the back of the brain that includes the visual cortex for vision.

Visual cortex

the area of the occipital lobe that receives visual information from the eyes. 

Temporal lobes

the portion of the cerebral cortex that lies roughly above the ears that includes the auditory cortex for hearing (audition).

Auditory cortex

the area of the temporal lobe that receives auditory information from the ears.

Association areas:

: the areas of the cerebral cortex involved in higher mental functions such as learning, remembering, thinking, and speaking.

Broca’s Area

an area of the left frontal lobe that controls the muscle movements involved in speech.  Damage to this area impairs speaking.

Wernicke’s Area:

an area of the left temporal lobe that is involved in language comprehension. Damage to this area impairs understanding.

Angular gyrus

an area of the left occipital lobe that transforms visual representation into an auditory code.

Aphasia

impairment of language usually caused by damage to the Broca’s Area or the Wernicke’s Area.

Neurogenesis

the formation of new neurons.

Corpus callosum

the large band of neural fibers that connect the left and right hemispheres to carry messages between them.  If the corpus callosum is severed, the two hemispheres cannot communicate.

Split brain

a condition in which the two hemispheres of the brain cannot communicate.  This is caused by the severing of the corpus callosum.

Alien Hand Syndrome

a rare neurological disorder that causes hand movement without the person being aware of what is happening or having control over the action. This usually occurs after a person has had the two hemispheres of the brain surgically separated, as in split-brain surgery.

 Cognitive neuroscience

the interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory and language).

Dual processing:

the principle that information is often simultaneously processed on separate conscious and unconscious tracks.

Phineas Gage

1800s railroad worker who had a tamping iron shoot through his left cheek and out the top of his skull.  He miraculously lived but massively damaged his frontal lobes.  The once calm and rational Gage became irritable and dishonest.  This paved the way for research on the functions of the frontal lobes.

Roger Sperry, Ronald Myers, and Michael Gazzaniga:

divided the brains of cats and monkeys with no serious ill effects.  Set the stage to study split brain in people.

behavior geneticists

the study of the relative power and limits of genetic and environmental influences on behavior, weigh the effects and interplay of heredity and enviornment

Chromosomes

threadlike structures made of DNA molecules that contain the genes

DNA

deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.

Genes

DNA segments that serve as the key functional units in hereditary transmission. biochemical units of heredity that make up that chromosomes ; segments of the DNA capable, of synthesizing proteins

genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

monozygotic twins

identical twins formed when one zygote splits into two separate masses of cells, each of which develops into a separate embryo, develop from a single fertilized egg that splits in two

dizygotic twins

(Fraternal Twins)- Develop from separate eggs and separate sperm, making them genetically no more similar than ordinary siblings, but they share a fetal environment

Separated Twin Study

Identification of an adult group of unquestionably monozygotic twins reared in separate, independent environments, whose study is potentially useful in determining the relative influences of heredity and environment

what role does our environment play on adopted children's personalities?

the genetic lease may limit the family environments influence on personality but parents do influence their children's attitudes, values, manners, faith, and politics

molecular genetics

the sub-field of biology that studies the molecular structure and function of genes. goal is to find some of many series that together orchestrate traits such as body weight, sexual orientation and extraversion