Nervous System and Neurotransmitters

• The brain and nervous system allows people to know when they are hurt.

The Nervous System

• Key components include neurons, dendrites, and axons
• It also includes the parasympathetic nervous system, myelin sheath, neurogenesis, and synapses
• The nervous system does not discuss action potential

Function of the Nervous System

• The nervous system gathers and processes information.
• It produces responses to stimuli.
• The nervous system coordinates the workings of different cells.
• The nervous system has two parts:
  • Central Nervous System
  • Peripheral Nervous System (PNS)

Central Nervous System

• The central nervous system includes the brain, spinal cord, and nerves.

Peripheral Nervous System (PNS)

• The peripheral nervous system is divided into:
  • Somatic (bodily) nervous system
  • Autonomic nervous system
    • Sympathetic nervous system
    • Parasympathetic nervous system

Chemical Messengers within the Nervous System

• Chemical Messengers within the nervous system include neurotransmitters.
• Chemical Messengers are important to follow a particular path.

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 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. It also affects neurons involved in learning, memory, dreaming, waking from sleep, and emotion.

Hormones

• Hormones are long-distance messengers released in the bloodstream

Specific Hormones

• Melatonin regulates daily biological rhythms and promotes sleep.
• Oxytocin stimulates uterine contractions during childbirth, facilitates the ejection of milk during nursing, and promotes attachment and trust in relationships.
• Adrenal hormones are involved in emotion and stress.
• The outer adrenal gland produces cortisol, which increases blood sugar levels and boosts energy.
• The inner part produces epinephrine/adrenaline and norepinephrine, which prepares the body for fight or flight.
• Sex hormones are androgens, estrogens and progesterone.
  • Androgens musicalize hormones and influences deepened voices, facial/chest hair, and sexual arousal.
  • Estrogens feminizes hormones during breast development and the onset of menstruation.
  • Progesterone aids growth and maintenance of the uterine lining for a fertilized egg.

Neuromodulators

• Neuromodulators control the brain's volume.
• Serotonin transporters pick up leftover serotonin and transport it back to the sending neuron for recycling.
• Endorphins: reduces pain and promotes pleasure, playing a role in appetite, sexual activity, blood pressure, mood, learning, and memory.

Happy Chemicals

• Happy chemicals promote happiness and pleasure while reducing depression and anxiety.
• These chemicals include Serotonin, dopamine, endorphins, and oxytocin.
• Endorphins are neuromodulators that help one cope with pain and stress, and dopamine is a mood-boosting neurotransmitter released after reaching a goal.

Mapping the Brain

• Ways to map the brain include electroencephalograms, PET scans (positron-emission tomography), transcranial direct current stimulation, transcranial magnetic stimulation, and lesion methods

Key Brain Components

• Pons are key for sleeping, waking, and dreaming
• Medulla is involves in bodily functions not consciously willed
• Cerebellum supports sense of balance and coordinating of the muscles and remembering simple skills and acquired reflexes
• Thalamus directs sensory messages to higher areas, except the sense of smell. The thalamus us a sensory relay station
• Hypothalamus is responsible for monitoring the body's current state and issue instruction to help the body maintain a steady state for basic survival drives
• Pituitary gland sends out hormonal messages
• Amygdala evaluates sensory information, determining it's emotional important to contribute to to the initial approach or withdraw feeling/action
• Hippocampus supports storage of new information in memory.
• Cerebrum is in charge of sensory, motor, and cognitive processes
• Cerebral hemispheres:
  • Right hemisphere controls the left side of the body
  • Left hemisphere controls the right side of the body

Lateralization in the Two Hemispheres

• Logic is commonly associated with the left hemisphere of the brain.
• Creativity is commonly associated with the right hemisphere of the brain.

Cerebral cortex

• Higher mental functions
• Lobes of the cortex:
  • Occipital lobes
  • Parietal lobes
  • Temporal lobes
  • Frontal lobes

Functions of Key Parts of the Brain

• Brain stem: involved in basic life functions.
• Pons: functions in sleeping, waking, and dreaming.
• Medulla: facilitates automatic functions, such as breathing and heart rate.
• Reticular activating system (RAS): extends into the center of the brain, screening incoming information and arousing higher centers of consciousness.
• Cerebellum: supports balance, muscular coordination, and memory for simple skills and learned reflexes.
• Thalamus: relays impulses from higher centers to the spinal cord and incoming sensory information, but not olfactory sensations, to other brain centers.
• Hypothalamus: controls survival behaviors like hunger, thirst, emotion, and reproduction, as well as regulating body temperature and the autonomic nervous system.
• Pituitary gland: directs the hypothalamus and secretes hormones, affecting other glands.
• Amygdala: evaluates sensory information to determine its importance and mediates anxiety, depression, and the formation/retrieval of emotional memories.
• Hippocampus: compares new sensory information with existing knowledge to regulate the RAS, also forming new memories about facts and events.
• Cerebrum (including cerebral cortex): involved in higher forms of thinking.
• Occipital lobes: supports visual processing.
• Parietal lobes: processes pressure, pain, touch, and temperature.
• Temporal lobes: functions in memory, perception, emotion, hearing, and language comprehension. Frontal lobes: responsible for movement, short-term memory, planning, setting goals, creative thinking, initiative, social judgment, rational decision making, and speech production.

Plasticity

• Plasticity is the brains ability to change in response to new experiences. It is most pronounced during infancy and early childhood, with a resurgence in adolescence.

Debunking Popular Psycology: His or Her Brain?

• Do the brains of males and females differ on average, in structure or function?
• If what differs, does so in men and women's behavior?

Test your knowledge of the nervous system and neurotransmitters. This quiz covers the roles of different neurotransmitters like serotonin, and dopamine. It also covers the functions of the somatic and autonomic nervous system.