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Neural and Hormonal Systems Neurons- a nerve cell; the basic building block of the nervous system. Each neuron consists of a Cell Body and its branching fibers. Dendrite fibers receive information and conduct it toward the cell body. Dendrites are short in comparison to axons. The Axon fiber passes the message through its terminal branches to other neurons or to muscles or glands. Axons may be very long, projecting several feet through the body. Some axons are encased in a Myelin Sheath, a layer of fatty tissue that insulates them and speeds their impulses. If the Myelin Sheath degenerates, multiple sclerosis results: Communication to the muscles slows, with eventual loss of muscle control. Dendrites Listen, Axons Speak. Supporting our billions of nerve cells are spidery Glial Cells or “Glue Cells”. Glial Cells provide nutrients and insulating myelin, guide neural connections, and clean up after neurons send messages to each other. Glia also play a role in learning and thinking. They participate in information transmission and memory.

The Neural Impulse Neurons transmit messages when stimulated by signals from our senses or when triggered by chemical signals from neighboring neurons. An Action Potential is an impulse sent by a neuron, described as a brief electrical charge that travels down its axon. Depending on fiber type, a neural impulse travels at speeds ranging from a sluggish 2 MPH to more than 200 MPH. Its top speed is 3 million times slower than that of electricity through a wire. Brain activity is measured in milliseconds(thousandths of a second) and computer activity in nanoseconds(billionths of a second. In the neuron’s chemistry-to-electricity process, Ions (electrically charged atoms) are exchanged. The fluid outside an axon’s membrane has mostly positively charged sodium ions.

How Neurons Communicate A Synapse is a meeting point between neurons. Neurotransmitters are chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse. Reuptake is the process of the sending neuron reabsorbing the neurotransmitter.

How Neurotransmitters Influence Us Acetylcholine(ACh)- is a neurotransmitter that plays a role in learning and memory. This neurotransmitter is also the messenger at every junction between motor neurons and skeletal muscles. When ACh is released, the muscle contracts. Enables muscle actions, learning and memory. Endorphins(Endogenous)- are natural, opiate-like neurotransmitters linked to pain control and to pleasure. The effects are similar to morphine. Influences the perception of pain or pleasure. Dopamine- Influences movement, learning, attention, and emotion. Oversupply has been linked to schizophrenia. Undersupply has been linked to tremors and decreased mobility in Parkinson’s disease. Serotonin- Affects mood, hunger, sleep, and arousal. Undersupply linked to depression. Some drugs that raise serotonin levels are used to treat depression. Norepinephrine- Helps control alertness and arousal. Undersupply can depress mood. GABA(Gamma-aminobutyric acid)- A major inhibitory neurotransmitter. Undersupply is linked to seizures, tremors, and insomnia. Glutamate- A major excitatory neurotransmitter; involved in memory. Oversupply can overstimulate the brain producing migraines or seizures. Agonist- molecules that increase a neurotransmitter’s action. May increase production or release of neurotransmitters, or block the reuptake in the synapse. Antagonists- Decrease a neurotransmitter’s action by blocking production or release.

The Nervous System The Nervous System- is the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems. The Central Nervous System(CNS)- is made up of the brain and spinal cord, referenced to as “the body’s decision maker. The Peripheral Nervous System(PNS)- is responsible for gathering information and for transmitting CNS decisions to other body parts. Nerves- are electrical cables formed of bundles of axons that link the CNS with the body’s sensory receptors, muscles, and glands. Sensory Neurons-(Afferent) Carry messages from the body’s tissues and sensory receptors inwards to the brain and spinal cord for processing. Motor Neurons-(Efferent) carry instructions from the CNS out to the body’s muscles and glands. Between the sensory input and motor output, information is processed via the Interneurons.

The Peripheral Nervous System(PNS) This specific nervous system has two components- Somatic and Autonomic. The Somatic Nervous System- Enables voluntary control of our skeletal muscles. The Autonomic Nervous System(ANS)- controls our glands and our internal organ muscles. The ANS influences functions such as glandular activity, heartbeat, and digestion. (Autonomic means “self-regulating.”) The ANS serves two important functions: The Sympathetic Nervous System- Which arouses and expends energy. If something challenges you, your sympathetic nervous system will accelerate your heartbeat, raise your blood pressure, slow your digestion, raise your blood sugar, and cool you with perspiration, making you alert and focused. The Parasympathetic Nervous System- produces the opposite effects, conserving energy as it calms you. The sympathetic and parasympathetic nervous systems work together to keep us in a steady internal state called homeostasis.

The Central Nervous System(CNS) The CNS consists of the brain and spinal cord. The spinal cord acts as a two-way information highway connecting the peripheral nervous system and the brain. Ascending neural fibers send up sensory information while descending fibers send back motor control information. Reflexes- are our automatic responses to stimuli.

The Endocrine System The Endocrine System is the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream. Hormones- Are chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues. When hormones act on the brain, they influence our interest in sec, food, and aggression. Hypothalamus- Brain region controlling the pituitary gland. Thyroid Gland- Affects metabolism Adrenal Glands- Inner part helps trigger the fight or flight response Testis- Secretes male sex hormones Pituitary Gland- A pea-sized structure located in the core of the brain that secretes many different hormones, some of which affect other glands. Parathyroids- Helps regulate the level of calcium in the blood Pancreas- Regulates the level of sugar in the blood Ovary- Secretes female sex hormones

The Brain Electroencephalogram(EEG)- is an amplified readout of electrical activity in your brain’s billions of neurons as they sweep in regular waves across its surface. PET Scan(Positron Emission Tomography)- depicts brain activity by showing each brain area’s consumption of its chemical fuel, the sugar glucose. MRI(Magnetic Resonance Imaging)- A person’s head is put into a strong magnetic field, which aligns the spinning atoms of the brain molecules. Then, a radio-wave pulse momentarily disorients the atoms. When the atoms return to their normal spin, they emit signals that provide a detailed picture of the soft tissues, including the brain. fMRI(Functional MRI)- Can reveal the brain's functioning as well as its structure.

Older Brain Structures The Brainstem is the brain’s oldest innermost region. It begins where the spinal cord swells slightly after entering the skull. Medulla- Slight swelling of the spinal cord slightly after entering the skull. This is the base of the Brainstem; controls the heartbeat and breathing. The Thalamus- is a pair of egg-shaped structures that act as the brain’s sensory control center. The thalamus receives information from all the senses except smell, and routes that information to higher brain regions that deal with seeing, hearing, tasting, and touching. The Cerebellum- meaning”little brain,”extends from the rear of the brainstem and is baseball-sized. The cerebellum enables non verbal learning and skill memory. “The brain’s organ of agility.” It also helps judge time, modulate our emotions, and discriminate sounds and textures.

The Limbic System The cerebral hemispheres are the two, newest and highest regions, halves of the brain. The Limbic System- lies between the oldest and newest brain areas. This system contains the amygdala, hypothalamus, and the hippocampus. The Hippocampus- processes conscious memories and decreases in size and function as we grow older. If the hippocampus is damaged, it can be hard to form new memories of facts and events. The Amygdala- is two lima bean-sized neural clusters linked to aggression and fear. The Hypothalamus- an important link in the command chain governing bodily maintenance. Some neural clusters here influence hunger; others regulate thirst, body temp, and sexual behavior.

The Cerebral Cortex and the Divided Brain The Cerebral Cortex- covers the cerebral hemispheres like bark on a tree, a thin surface layer of interconnected neural cells. It is your brain’s thinking crown, your body’s ultimate control and information processing center. Structure of the Cortex Frontal Lobes- (Behind the forehead) involved in speaking and muscle movements and in making plans and judgements. Parietal Lobes- (At the top and to the rear) receives sensory input for touch and body position. Occipital Lobes- (At the back of the head) includes areas that receive information from the visual fields. Temporal Lobes- (Just above the ears) includes the auditory areas, each receiving information primarily from the opposite ear. Motor Cortex- An area at the rear of the frontal lobes that controls voluntary movements. Somatosensory Cortex- An Area at the front of the parietal lobes that registers and processes body touch and movement. Association Areas- Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking. Frontal lobe damage also can alter personality and remove a person’s inhibitions. Moral judgements may seem unrestrained.

The Brain’s Plasticity Plasticity is the ability to modify itself after damage. Plasticity may also occur after serious damage, especially in young children. Two Hard Facts 1. Severed brain and spinal cord neurons, unlike cut skin, usually do not regenerate. 2. Some brain functions seem preassigned to specific areas. Sometimes the brain tries producing new brain cells in attempt to mend itself instead of reorganizing existing tissue. This process is known as neurogenesis.

Our Divided Brain Corpus Callosum- is the wide band of axon fibers connecting the two hemispheres that carries messages between them. Split Brains- is a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers connecting them. After a split brain surgery, the left hemisphere handles speaking while the right handles movement, the two cannot pass the information between them.

Genes: Our Codes for Life Chromosomes- Threadlike structures made of DNA molecules that contain the genes. We as humans contain at least 46 of these. DNA- A complex molecule containing the genetic information that makes up the chromosomes. Genes- The biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins. Genome- The complete instructions for making an organism, consisting of all genetic material in that organism’s chromosomes.

Twin and Adoption Studies Identical(monozygotic) Twins- developed from a single fertilized egg that splits in two, creating two genetically identical organisms, Fraternal(dizygotic) Twins- Develop from separate fertilized eggs. They are genetically no closer than ordinary brothers and sisters, but they share a prenatal environment. Epigenetics- The study of environmental influences on gene expression that occur without a DNA change.

Cognitive Development Cognitive- All the mental activities associated with thinking, knowing, remembering, and communicating. Schemas- A concept or framework that organizes and interprets information. Assimilate- Interpreting our new experiences in terms of our existing schemas. Accommodate- In developmental psychology, adapting our current understandings (schemas) to incorporate new information.

Piaget’s Theory and Current Thinking Piaget believed that children construct their understanding of the world while interacting with it. Sensorimotor Stage- (From birth to nearly 2 years of age) during which infants know the world mostly in terms of their sensory impressions and motor activities. Preoperational Stage-(From 2- about 6 or 7 years old) stage during which a child learns to use language but does not yet comprehend the mental operations of concrete logic. Concrete Operational Stage-(From 7-11 Years of age) Thinking logically about concrete events; grasping concrete analogie and performing arithmetic operations. Formal Operational Stage-(From about 12 to Adulthood) Abstract reasoning Object Permanence- The awareness that things continue to exist even when not perceived.

Conservation- The principle that properties such as mass, volume, and number remain the same despite changes in forms of objects. Egocentric- The preoperational child’s difficulty taking another’s POV Theory of Mind- Peoples ideas about their own and others mental states- their feelings, perceptions, and thoughts, and the behaviors these might predict.

Social Development Stranger Anxiety- The fear of strangers that infants commonly display, beginning by about 8 months of age. Attachment- An emotional tie with another person; shown in young children by their seeking closeness to the caregiver and showing distress on separation. Imprinting- The process by which certain animals form strong attachments during early life.

Adolescence The transition period from childhood to adulthood, extending from puberty to independence. Puberty- The time when we mature sexually, when a person becomes capable of reproducing. Key Concepts from this Week: ● Humans develop through a complex interaction between nature and nurture. Our genes and biology affect not only who we are but how we experience our environment. ● The brain consists of three major structures. Primitive areas, such as the brainstem, medulla, and pons, control processes important to basic survival; the limbic system helps regulate the body, emotions, and communication between the primitive and higher-order structures; and the more evolved cerebral cortex is involved in complex, higher-order information processing. ● A neuron is made up of a cell body, dendrites (which extend like branches from the cell body), and a long, tail-like axon. A neuron communicates by sending an electrical signal down the axon to initiate the release of chemicals (neurotransmitters) into a space between neurons (the synapse). ● The nervous system has two main parts: the central and peripheral nervous systems. The central nervous system is made up of the brain and spinal cord. The peripheral nervous system relays information between the central nervous system and the rest of the body. ● Two components of the peripheral nervous system are the sympathetic and parasympathetic nervous systems. The sympathetic nervous system creates the physiological reactions of the fight-or-flight response, which prepares the body to act in the face of a real or perceived threat. The parasympathetic nervous system allows the body to calm down when the threat has passed. ● Neurodiversity is a concept that emphasizes that differences in brain functioning should be respected and understood just like any other human variation. ● Jean Piaget identified stages of cognitive development that describe how children use increasingly sophisticated schemas—mental categories and strategies—to understand their world. When we encounter new information, Piaget said, we either assimilate the new information into our existing schemas, or we accommodate our schemas to account for the new information. ● Lev Vygotsky argued that children receive all their schemas and information from their culture. ● As children age, they develop emotionally, form relationships, and adjust to physical changes and challenges. ● The areas of the brain responsible for rational decision making are still developing in adolescence. This ongoing development explains some of the characteristically impulsive behavior of teenagers. ● Adulthood presents its own challenges and opportunities to continue developing cognitively, emotionally, and socially. ● Culture is a lens that we use to make sense of the world around us. The diversity of cultures shapes our differences as well as our similarities. When we’re open to seeing through the lens of others, we have a valuable opportunity to enhance our emotional intelligence.

The Seven Perspectives of Psychology on the Nature vs Nurture Spectrum ←—------------------------------------------------------------------------------------------> Neuroscience Evolutionary Behavior Genetics

Cognitive

Psychodynamic Behavioral Social-cultural

● Neuroscience Perspective- Focuses on biological influences on human behavior by studying the body and the brain, including brain chemistry. Neuroscientists look for causes of behavior that may be rooted in nature, such as brain structure or imbalance neurotransmitters. However, they also study how the brain and brain chemistry change in response to learning, damage, and environmental factors such as emotional abuse or air pollution.(Honeycutt, 2019) ● Evolutionary Perspective- Focuses on how natural selection promotes the survival and reproduction of genes. Evolutionary psychologists tend to focus on the contributions of nature by explaining why certain behaviors were, at some point in our ancestors’ lives, advantages that helped our species survive(Honeycutt, 2019) However, this perspective also considers how we adapt to our environment and how those adaptations, if successful, get passed onto the next generation. ● Cognitive Perspective- focuses on how we encode, process, and store information in the mind. Nurture plays a large role in our cognition because we constantly come into contact with new information from our environment (Lewkpwicz, 2011). Some cognitive psychologists, though, take the nativist position. These psychologists argue that we have certain innate mental structures that explain why we all learn and categorize information in a similar way at the various stages of development- even if the exact content of what we learn is different (Honeycutt, 2019). ● Psychodynamic Perspective- studies how behavior might be caused by repressing or resolving unconscious drives and desires. Sigmund Freud (1920) believed that all humans are born with two innate psychological drives- Eros (Life) and Thanatos (Death)- that are in constant conflict. However, social rules and expectations are often at odds with our instincts, so our behavior is the result of this constant and dynamic conflict between nature (instincts) and nurture (society’s rules). ● Behavioral Genetics Perspective- focus on how we learn observable behavior. This perspective primarily studies how behavior is nurtured by the environment through primarily forming associations, modeling how to act, or responding with punishments or rewards. Behavioral psychologists recognize that there are certain behaviors, called reflexes, that seem to be determined by nature- but argue that these reflexes are often starting points for learned behavior. For example, a healthy newborn does not learn how to cry when in distress, but quickly learns whether its parents will respond to the cries. Humans do not develop in isolation, relying solely on our innate or reflexive behavior- we develop by interacting with our environment (Garve, 2005). ●

Social-Cultural Perspective- focuses on...