Brain and Nervous System

• The notes cover the brain and the nervous system.
• They address how the brain knows to feel hurt.

The Nervous System

• It gathers and processes information.
• It produces responses to stimuli.
• It coordinates the workings of different cells.
• It contains the Central Nervous System and the Peripheral Nervous System (PNS).

Central Nervous System

• Includes the brain, spinal cord, and nerves.

Peripheral Nervous System (PNS)

• Includes the Somatic (bodily) nervous system.
• Includes the Autonomic nervous system, which includes both the sympathetic nervous system and parasympathetic nervous system.

Chemical Messengers in the Nervous System

• Includes neurotransmitters, and hormones.
• Neurotransmitters follow a particular path.
• Hormones are long-distance messengers released in the bloodstream.

Neurotransmitters

• Serotonin affects neurons involved in sleep, appetite, sensory perception, temperature regulation, pain suppression, and mood.
• Dopamine affects neurons involved in voluntary movement, attention, learning, memory, emotion, pleasure and reward, and possibly responses to novelty.
• Acetylcholine affects neurons involved in muscle action, arousal, vigilance, memory, and emotion.
• Norepinephrine affects neurons involved in increased heart rate and the slowing of intestinal activity during stress, and neurons involved in learning, memory, dreaming, waking from sleep, and emotion.

Hormones

• Melatonin helps to regulate daily biological rhythms and promotes sleep.
• Oxytocin stimulates uterine contractions during childbirth, facilitates the ejection of milk during nursing, and promotes, in both sexes, attachment and trust in relationships.
• Adrenal hormones are involved in emotion and stress.
  • The outer part of each adrenal gland produces cortisol, which increases blood sugar levels and boosts energy.
  • The inner part produces epinephrine/adrenaline and norepinephrine, which prepare the body for fight or flight.

Sex Hormones

• Androgens effect musicalizing hormones, deepened voice, facial and chest hair, pubic hair, and testosterone, which influences sexual arousal.
• Estrogens are feminizing hormones that support breast development and the onset of menstruation.
• Progesterone supports the growth and maintenance of the uterine lining for a fertilized egg.

Neuromodulators

• The brain's volume control.
• Serotonin transporters pick up leftover serotonin and transport it back to the sending neuron for recycling.
• Endorphins reduce pain.
  • They promote pleasure.
  • They play a role in appetite, sexual activity, blood pressure, mood, learning, and memory.
• Happy chemicals are a type of neuromodulators and neurotransmitters that help promote happiness and pleasure while reducing depression and anxiety.
  • These include the neurotransmitters serotonin, dopamine, the neuromodulators endorphins, and the hormone oxytocin.
• Endorphins are released before coping with pain and stress, while dopamine is released after reaching a goal.

Mapping the Brain

• Structures include: cerebrum, cerebral cortex, corpus callosum, thalamus, hypothalamus, pituitary gland, pons, reticular activating system, medulla, and cerebellum.
• The Pons is responsible for sleeping, waking, and dreaming.
• The Medulla is responsible for bodily functions that do not have to be consciously willed.
• The Cerebellum effects the sense of balance, coordinates the muscles, and remembers simple skills and acquired reflexes.
• The Thalamus is a sensory relay station that directs sensory messages to higher brain areas in charge of vision, sound, or touch, but not smell.
• The Hypothalamus monitors the body's current state and issues instructions to help the body maintain a steady state, fulfilling basic survival drives.
• The Pituitary glad sends out hormonal messages and is under direction of the hypothalamus.
• The Amygdala evaluates sensory information, quickly determining its emotional importance and contributes to the initial decision to approach or withdraw from a person or situation.
• The Hippocampus is responsible for the storage of new information in memory.
• The Cerebrum is in charge of most sensory, motor, and cognitive processes.
  • The right cerebral hemisphere controls the left side of the body.
  • The left cerebral hemisphere controls the right side of the body.

Lateralization in the Two Hemispheres

• Language, numbers, and analytical thinking depend on the left hemisphere of the brain which supports logic.
• Expression, emotional intelligence and imagination depend on the right hemisphere of the brain which supports creativity.
• The Cerebral Cortex effects higher mental functions.
• The Lobes of the cortex include: occipital lobes, parietal lobes, temporal lobes, and frontal lobes.

Some Key Parts of the Brain

• Includes the brain stem, pons, medulla, reticular activating system (RAS), cerebellum, thalamus, hypothalamus, pituitary gland, amygdala, hippocampus and cerebrum including cerebral cortex.
• The functions include:
  • sleeping, waking, dreaming, automatic functions such as breathing, heart rate, screening of incoming information, arousal of higher centers, consciousness.
  • Balance, muscular coordination, memory for simple skills and learned reflexes, involvement in cognitive and emotional learning.
  • Relay of impulses from higher centers to the spinal cord and of incoming sensory information (except for olfactory sensations) to other brain centers, behaviors necessary for survival, such as hunger; thirst, emotion, reproduction; regulation of body temperature; control of autonomic nervous system.
  • Under direction of the hypothalamus, secretion of hormones that affect other glands, initial evaluation of sensory information to determine its importance; mediation of anxiety and depression; formation and retrieval of emotional memories, comparison of new sensory information with existing knowledge in order to regulate the RAS; formation of new memories about facts and events, as well as other aspects of memory, and higher forms of thinking.
• Occipital lobes are responsible for visual processing.
• Parietal lobes are responsible for processing of pressure, pain, touch, and temperature.
• Temporal lobes are responsible for memory, perception, emotion, hearing, and language comprehension.
• Frontal lobes are responsible for movement, short-term memory, planning, setting goals, creative thinking, initiative, social judgment, rational decision making, and speech production.

Is Our Brain Flexible?

• Plasticity describes the brain's ability to change in response to new experiences.
• Plasticity is most pronounced during infancy and early childhood.
• Plasticity has a resurgence in adolescence.

This lesson explores the nervous system, its central and peripheral components, and its function in gathering and processing information. It also discusses chemical messengers, including neurotransmitters like serotonin and dopamine, and hormones, which influence various bodily functions and mood.