Biological Foundations of Behavior Lesson PDF

BIOLOGICAL FOUNDATIONS OF BEHAVIOR  Neurons and the Nervous System  The Brain and its Structures  Endocrine System  Genetics and Behavior Neurons and the Nervous System  NEURONS  The building blocks of the nervous system.  Neurons are specialized cells responsible for transmi...

BIOLOGICAL FOUNDATIONS OF BEHAVIOR  Neurons and the Nervous System  The Brain and its Structures  Endocrine System  Genetics and Behavior Neurons and the Nervous System  NEURONS  The building blocks of the nervous system.  Neurons are specialized cells responsible for transmitting information throughout the body.  They communicate via electrical impulses (action potentials) and chemical signals (neurotransmission).  The combined process of electrical impulses and chemical signals in neural communication is called neurotransmission or neural signaling.  Electrical Impulses (Action Potential)  Type of Signal: Electrical  Location: They travel along the axon of a neuron to transmit signals within the neuron.  Chemical Signals (Neurotransmission)  Type of Signal: Chemical  Location: Occurs between neurons, across the synapse (the gap between the axon terminal of one neuron and the dendrites of another).  THE STRUCTURE OF NEURONS  Cell Body (Soma): Contains the nucleus and genetic material. It processes incoming signals.  Dendrites: Branch-like structures that receive signals from other neurons.  Axon: A long fiber that transmits electrical signals away from the cell body to other neurons, muscles, or glands.  Nucleus – contains the genetic material of neuron cell.  Myelin Sheath: A fatty layer that insulates the axon, speeding up the transmission of signals.  Axon Terminals: Small branches at the end of the axon that release neurotransmitters to communicate with other neurons.  Synapse: The gap between the axon terminal of one neuron and the dendrite of another neuron where neurotransmission occurs.  TYPES OF NEURONS  Sensory Neurons (Afferent)  Carry information from sensory organs (skin, eyes, ears) to the central nervous system (CNS).  Motor Neurons (Efferent)  Carry signals from the CNS to muscles and glands, resulting in movement or action.  Interneurons: Connect sensory and motor neurons and are primarily located in the CNS. They process and interpret information.  Neurotransmitters  Are chemical messengers that transmit signals across synapses from one neuron (nerve cell) to another, or to a muscle or gland. 1. Transmitting Signals Between Neurons 2. Regulating Bodily Functions 3. Affecting Mood and Emotions 4. Influencing Learning and Memory 5. Regulating Stress and Arousal 6. Controlling Pain Perception 1. Acetylcholine: Involved in muscle activation, attention, and memory. It plays a role in the autonomic nervous system and helps regulate heart rate and digestion. 2. Dopamine: Important for reward, motivation, and motor control. It is associated with feelings of pleasure and is involved in addiction, mood regulation, and conditions like Parkinson's disease and schizophrenia. 3. Serotonin: Regulates mood, appetite, and sleep. Low levels of serotonin are often linked to depression and anxiety disorders. 4. Norepinephrine: Influences alertness, arousal, and the body's stress response (fight-or- flight response). It is also involved in mood regulation. 5. GABA (Gamma-Aminobutyric Acid): The main inhibitory neurotransmitter in the brain, which reduces neural activity and prevents overstimulation, helping with relaxation and sleep. 6. Glutamate: The most common excitatory neurotransmitter, crucial for learning and memory. However, excessive glutamate can lead to excitotoxicity, which may damage nerve cells. 7. Endorphins: Natural painkillers that also promote feelings of pleasure or euphoria. They are released during activities like exercise, often referred to as a "runner's high."  These neurotransmitters work together to maintain balance in the body and brain, affecting behavior, mood, and physical processes.  They are found throughout the nervous system, bridging the communication between neurons and influencing various bodily functions.  THE NERVOUS SYSTEM  A complex network of cells and tissues responsible for controlling and coordinating the body’s activities.  It gathers information from both inside and outside the body, processes that information, and then sends signals to different parts of the body to elicit appropriate responses.  DIVISIONS OF NERVOUS SYSTEM  Central Nervous System (CNS)  Peripheral Nervous System (PNS)  Central Nervous System (CNS)  The primary control center of the body, consisting of the brain and the spinal cord.  It plays a vital role in regulating bodily functions, processing sensory information, and coordinating responses.  Brain: The control center for thoughts, emotions, memory, movement, and sensation. a. Cerebrum: The largest part, responsible for voluntary actions, thinking, memory, and sensory processing. a.1 Cerebral Cortex: Responsible for higher cognitive functions such as thinking, decision-making, and language. a.1.1 Frontal Lobe  Associated with reasoning, planning, problem-solving, and voluntary motor activity.  Contains the primary motor cortex, which controls voluntary muscle movements. a.1.2 Parietal Lobe:  Processes sensory information such as touch, temperature, and pain.  Contains the primary somatosensory cortex, which interprets signals from various parts of the body. a.1.3 Temporal Lobe:  Responsible for processing auditory information and is important for memory and language.  Houses structures like the hippocampus, critical for memory formation. a.1.4 Occipital Lobe:  Primarily responsible for visual processing.  Contains the primary visual cortex, which interprets visual information from the eyes. b.1 Limbic System: Controls emotions and memory. b.1.1 Amygdala  Involved in processing emotions, especially fear and pleasure.  Plays a role in recognizing emotions in others and forming emotional memories. b.1.2 Hippocampus:  Critical for the formation of new memories and spatial navigation.  Helps convert short-term memories into long-term memories. b.1.3 Hypothalamus:  Regulates bodily functions like hunger, thirst, body temperature, and circadian rhythms.  Connects the nervous system to the endocrine system, influencing the release of hormones.  Plays a role in the "fight or flight" response to stress. b.1.4 Thalamus:  Acts as a relay station, processing and transmitting sensory information to the cerebral cortex.  Involved in regulating consciousness, sleep, and alertness. b.1.5 Cingulate Gyrus:  Regulates emotions and pain.  Involved in controlling the body's emotional responses to physical and social stimuli. b. Cerebellum: Controls coordination, balance, and fine motor movements. c. Brainstem: Manages basic life functions like breathing, heart rate, and sleep cycles. It connects the brain to the spinal cord. c.1 Midbrain  Uppermost part of the brainstem.  Involved in visual and auditory processing.  Controls eye movements and reflexive responses to visual and auditory stimuli. c.2 Pons  Below the midbrain and above the medulla oblongata.  Acts as a bridge connecting different parts of the nervous system, including the cerebellum and the cerebral cortex.  Plays a role in regulating breathing, communication between brain regions, and sensations such as hearing, taste, and balance. c.3 Medulla Oblongata  Lowermost part of the brainstem, connecting to the spinal cord.  Controls vital autonomic functions such as heart rate, blood pressure, and breathing.  Contains reflex centers for coughing, sneezing, swallowing, and vomiting.  Houses nuclei for several cranial nerves involved in functions like taste, hearing, and balance.  Peripheral Nervous System (CNS)  Is a crucial component of the nervous system that connects the central nervous system (CNS) to the rest of the body.  It includes all the nerves and ganglia outside the brain and spinal cord.  The PNS plays a vital role in transmitting sensory information to the CNS and relaying motor commands from the CNS to various parts of the body.  COMPONENTS OF THE PERIPHERAL NERVOUS SYSTEM  Cranial Nerves  Spinal Nerves  Cranial Nerves  There are 12 pairs of cranial nerves that emerge directly from the brain, primarily the brainstem.  These nerves are responsible for various functions, including sensory perception, motor control, and autonomic functions.  Spinal Nerves:  There are 31 pairs of spinal nerves that emerge from the spinal cord.  Each spinal nerve consists of sensory (afferent) and motor (efferent) fibers.  Spinal nerves are organized into five regions:  Cervical Nerves (8 pairs): Control movements and sensations of the neck, arms, and diaphragm.  Thoracic Nerves (12 pairs): Control the chest and abdominal muscles.  Lumbar Nerves (5 pairs): Control the lower back and legs.  Sacral Nerves (5 pairs): Control the pelvis and lower limbs.  Coccygeal Nerve (1 pair): Associated with the tailbone region.  Thoracic Nerves (12 pairs): Control the chest and abdominal muscles.  Lumbar Nerves (5 pairs): Control the lower back and legs.  Sacral Nerves (5 pairs): Control the pelvis and lower limbs.  Coccygeal Nerve (1 pair): Associated with the tailbone region. The Endocrine System  The endocrine system is a network of glands that produce and release hormones to regulate various functions in the body, such as metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood.  It works closely with the nervous system to maintain homeostasis and respond to changes in the environment.  Hypothalamus  Connects the endocrine and nervous systems.  It controls the pituitary gland and regulates hunger, thirst, sleep, and body temperature.  Pituitary Gland:  Known as the "master gland," it releases hormones that regulate other endocrine glands, such as the thyroid, adrenal glands, and reproductive organs.  Thyroid Gland  Regulates metabolism, energy levels, and growth through the production of thyroid hormones (T3 and T4).  Parathyroid Glands  Control calcium levels in the blood, which is important for bone health and muscle function.  Adrenal Glands  Produce hormones like cortisol and adrenaline, which help the body respond to stress and regulate metabolism and immune response.  Pancreas  Has both endocrine and exocrine functions; it regulates blood sugar levels by producing insulin and glucagon.  Pineal Gland  Produces melatonin, which influences sleep-wake cycles.  Ovaries (in females)  Produce estrogen and progesterone, which regulate the menstrual cycle, pregnancy, and secondary sexual characteristics.  Testes (in males)  Produce testosterone, which regulates sperm production and secondary sexual characteristics.  Liver  The liver produces and releases insulin-like growth factor 1 (IGF- 1) that works in conjunction with growth hormone to stimulate growth and development,  thrombopoietin that will regulate platelet production and  angiotensinogen which is the precursor involved in blood pressure regulation as part of the renin-angiotensin system.  Kidneys  Has Erythropoietin (EPO) that Stimulates red blood cell production in response to low oxygen levels in the blood,  Renin that involved in blood pressure regulation through the renin-angiotensin-aldosterone system and  calcitriol (Active Vitamin D) that regulates calcium and phosphate balance, influencing bone health. Importance of Endocrine System  Regulation of Metabolism and Energy Balance  Growth and Development  Regulation of Reproduction  Response to Stress  Maintenance of Homeostasis  Regulation of Mood and Emotional Well-being  Immune System Function  Regulation of Sleep Cycles  Adaptation to Environmental Changes Genetics and Behavior  Genetics and behavior is a field that explores how genetic makeup influences behaviors and the interaction between genetics and the environment in shaping an individual's actions, personality, and psychological traits.  It recognizes that while genes provide the blueprint for various aspects of behavior, environmental factors and life experiences also play crucial roles. The Biological Blueprint  Genes are long molecules of deoxyribonucleic acid (DNA) that are located at various chromosomal sites within the cell nucleus.  The first 22 pairs of chromosomes provide programs or directions for the development of the body and brain, and the last pair, called the sex chromosomes, determines an individual’s sex.  In females, both chromosomes in the 23rd pair are called X chromosomes. In males, the mother contributes an X chromosome, but the father contributes a Y chromosome. This one difference is responsible for the variance in biological sex. Key Concepts in Genetics  Describe an organism's genetic makeup and its observable characteristics.  GENOTYPE  The genotype is the genetic makeup of an organism. It refers to the specific set of genes inherited from both parents that influence various traits.  PHENOTYPE  The phenotype is the observable physical or physiological traits of an organism, which result from the interaction of its genotype with the environment.  The best estimate for genetic contribution to enduring personality traits and cognitive abilities in humans is about 50%. However, adverse experiences, such as a chaotic childhood, may “overwhelm” the influence of genes.  With respect to psychological disorders, genetic influences seem to account for less than half the etiological explanation; this varies somewhat from disorder to disorder.  Current evidence is that genetic contributions to psychological disorders most likely come from many genes, each having a small effect.