1.1 Introduction of Heredity and Environment

• Nature VS Nurture

  • Nature is the genetic makeup and biological traits that we inherit from our parents.

  • Nurture is all the environmental influences that impact an individual after birth.

• Natural Selection

  • The process by which traits that enhance survival and reproductive successes are more likely to be passed on to the next generations. The evolutionary mechanism leads to the adaptation of organisms to their environment over time.

• Eugenics

  • A belief and practice aimed at improving the genetic quality of a human population by selectively breeding for desirable traits, often through unethical means.

• Twin Study

  • Compares identical and fraternal twins to understand how much a trait is influenced by genetics vs environment, using twins raised together and sometimes those raised apart.

• Adoption Study

  • Examines the similarities and differences between adopted children and their biological and adoptive families to separate the effects on the environment from those of genetics on human development

• Family Study

  • Looks at behavioral and medical histories within a family to identify how certain traits or disorders are passed down through generations, highlighting genetical influences and familial patterns.

1.2 Overview of the Nervous System

• Nervous System

  • The complex network of nerves and neurons that carries messages to and from the brain and spinal cord to various parts of the body, coordinating voluntary and involuntary actions.

  • Consists of two main parts

    • Central Nervous System- Contains brain and spinal cord

    • Peripheral Nervous System - Contains nerve endings that branch out from the spinal cord and extend throughout the body

      • Somatic Nervous System - Manages our voluntary movements and transmits sensory information to the central nervous system

      • Autonomic Nervous System - Involuntary bodily functions, operating primarily below the level of consciousness

        • Sympathetic Nervous System- Activates fight or flight response

        • Parasympathetic Nervous System - Activates rest and digest

1.3 The Neuron and Neural Firing

• The Neuron

  • A specialized cell in the nervous system that transmits information to other nerve cells, muscle cells, or gland cells, primarily through electrical and chemical signals.

• Glial Cells

  • Cells that support, protect, and nourish neurons; they are essential for maintaining the environment in which the neurons function.

• Sensory Neurons

  • Converting external stimuli from the environment into internal electrical impulses.

• Motor Neurons

  • Transmits signals from the spinal cord to the muscles or glands, triggering action.

• Interneurons

  • Connect other neurons within the brain and spinal cord, facilitating communication and reflex responses.

• Reflex Arc

  • The neural pathway that mediates a reflex action, involving sensory neurons, interneurons, and motor neurons without conscious brain involvement.

• Action Potential

  • A rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane as a nerve cell responds to a stimulus.

• Stimulus Threshold

  • The minimum level of stimulation required to trigger an action potential in a neuron.

• All or nothing Principle

  • A neuron either fires completely when the stimulus threshold is reached or does not fire at all.

• Refractory Period

  • The time immediately following an action potential during which a neuron is unable to fire another action potential.

• Resting Potential

  • The neuron is prepared to send another message when stimulated.

• Reuptake

  • The process by which neurotransmitters are taken back into the neurotransmitter-releasing neuron after transmitting a neural impulse

• Multiple Scelrosis (MS)

  • An autoimmune disorder that affects the central nervous system by degrading the myelin sheath, disrupting communication between the brain and body.

• Myasthenia Gravis (MG)

  • A neuromuscular disease that weakens the skeletal muscles responsible for breathing and moving parts of the body, primarily caused by an autoimmune disruption of communication between nerves and muscles.

• Neurotransmitters

  • Chemicals released by neurons that transmit signals across a synapse to other neurons.

    • Excitatory message - A neural message that increases the likelihood that the neuron receiving the message will fire an action potential, speeding up brain activity.

    • Inhibitory Message - A neural message that decreases the likelihood that the neuron receiving the message will fire an action potential, slowing down brain activity.

• Dopamine

  • Plays a key role in the brains reward system, influencing feelings of pleasure and motivation.

• Serotonin

  • Regulates mood, appetite, and sleep, often associated with feelings of well-being and happiness. Also plays a role in memory and learning.

• Norepinephrine

  • A neurotransmitter and hormone that plays a crucial role in the body’s fight or flight response, increasing alertness and arousal. Also helps regulate mood and attention.

• Glutamate

  • Most abundant excitatory neurotransmitter in the brain, essential for learning and memory. It plays a critical role in synaptic plasticity.

• GABA

  • Primary inhibitory neurotransmitter in the brain, helping to reduce neuronal excitability and promote relaxation. Plays a key role in regulating anxiety.

• Endorphins

  • Natural painkillers, reducing pain perception and inducing feelings of pleasure or euphoria. Released in response to stress, pain, and exercise.

• Substance P

  • Involved in transmitting pain signals from the peripheral nervous system to the central nervous system. Plays a key role in the body’s response to pain and inflammation.

  • Acetylcholine

    • Essential for muscle contractions, memory, and learning.

• The Endocrine System

  • A network of glands throughout the body that secrete hormones directly into the bloodstream.

  • Controlled by hypothalamus and pituitary gland

• Adrenaline plays a big role in fight or flight response. When released, it prepares your body into action by increasing your heart rate, blood pressure, and energy supplies

• Leptin is released by our fat cells and helps with regulating our energy balance by telling our body when to stop eating, suppressing our appetite,

• Ghrelin is released into the stomach to stimulate our apetite

• Melatonin is released by pineal gland, helps to prepare us for sleep. When the sun starts to rise, melatonin production starts to decrease.

• Oxytocin plays a significant role in social bonding and reproduction. It is released as a result of physical touch and is thought to reduce stress by also improving our overall emotional well being.

• Psychoactive drugs

  • Substances that alter brain function leading to changed in perception, mood consciousness, and behavior. Drugs can affect neurotransmitter systems and are often used for both therapeutic purposes and recreationally, but they can also lead to dependence and addiction.

• Agonist

  • A substance that binds to a receptor in the brain and mimics or enhances the action of a neurotransmitter, leading to an increase in its effects.

• Antagonist

  • A substance that binds to a receptor and blocks or reduces the effect of a neurotransmitter, thereby inhibiting its activity. By preventing the neurotransmitter from exerting its effects, antagonists can decrease or neutralize the physiological response.

  • Reuptake Inhibitor

    • Block the process of reuptake to increase the levels of a specific neurotransmitter in the brain.

  1.4 The Brain

  

  The Brain Stem

• Medulla

  • Responsible for controlling automatic functions. Serves as a critical pathway for neural signals between the brain and the spinal cord.

• Cerebellum

  • Responsible for motor control, coordinating voluntary movements, and helps with speech.

  • Reticular Activating System

    • A network of neurons located in the brainstem that plays a key role in regulating arousal, alertness, and the sleep-wake cycle.

  The Limbic System

• Thalamus

  • Acts as brain sensory relay station, channeling incoming sensory information to appropriate areas of the brain. Smell is not processed by thalamus.

• Hypothalamus

  • Responsible for regulating vital life functions

  • Four F’s: Fighting, Fleeing, Feeding, and Fucking

• Pituitary Gland

  • Master gland of the endocrine system, influencing other glands in the body. Regulates growth, metabolism, and reproduction.

  • Controlled by the hypothalamus

• Hippocampus

  • Creates new memories

• Amygdala

  • Critical for processing emotions

The Cerebral Cortex

• Corpus Callosum

  • A thick band of nerve fibers that connects the left and right hemispheres of the brain.

• Occipital Lobe

  • Region in the back of the brain that is responsible for processing visual information

• Temporal Lobe

  • Region that deals with interpreting auditory information and sounds

• Parietal Lobe

  • Positioned at the top of the brain and processes sensory signals from various parts of the body, making it crucial for spatial orientation and navigation.

• Frontal Lobe

  • Decision making, problem solving, planning, and controlling speech and motor movements.