AP PSYCHOLOGY: UNIT II Introductory Psychology: Biological Bases of Behavior Topic: Nervous System and Endocrine System

PART ONE The Biological Bases: Central Nervous System DEFINITION: The CNS is composed of the brain & the spinal cord, both of which are composed of neurons and glial cells that control the life-sustaining functions of the body as well as all thought, emotion and behavior THE BODY’S COMMAND CENTER

Biological Bases: Central Nervous The brain is the TRUE CORE of the nervous system  Interprets information  Makes decisions  Sends commands Despite the importance of the brain, it would be completely useless without the spinal cord

Biological Bases: Central Nervous The Spinal Cord  A long bundle of neurons; connects the brain to the body; also responsible for fast, lifesaving reflexes  Carries information from the body’s tissues & sensory organs to the brain (via afferent {sensory} neurons)  Carries motor impulses from the brain to the body’s muscles and glands (via efferent {motor} neurons)

Biological Bases: Central Nervous The Reflex Arc

Biological Bases: Central Nervous The Reflex Arc

PART TWO The Biological Bases: Peripheral Nervous System DEFINTION: The PNS is made up of all the nerves and neurons that lie outside the brain & spinal cord; allows the brain & spinal cord to communicate with the sensory systems of the eyes, ears, skin, and mouth and allows the brain & spinal cord to control the muscles & glands of the body

Biological Bases: Peripheral Nervous The PNS can be divided into TWO major systems  Somatic Nervous System  Autonomic Nervous System  Sympathetic Nervous System  Parasympathetic Nervous System

Biological Bases: Peripheral Nervous Somatic Nervous System  Characteristics  Sensory Pathway All of the nerves that carry messages from the senses to the central nervous system; contain afferent neurons  Motor Pathway All of the nerves that carry messages from the central nervous system to the voluntary muscles of the body; contain efferent neurons

Biological Bases: Peripheral Nervous Autonomic Nervous System  Characteristics  More or less automatic  Controls organs, glands & involuntary muscles Comprised of two systems Sympathetic Nervous System Parasympathetic Nervous System

Biological Bases: Peripheral Nervous Sympathetic Nervous System  Characteristics  Located in the middle of the spinal column  Reacts to stressful events & bodily arousal  “Fight-or-Flight” System  Specific Reactions?  Dilates pupils  Increases heart rate & breathing  Stops digestion & excretion The sympathetic division demonstrates sympathy for one’s emotions

Biological Bases: Peripheral Nervous Parasympathetic Nervous System Characteristics  Located on either side of the sympathetic division  Restores the body to normal functioning after arousal  “Rest-and-Digest” System  Specific Reactions?  Constricts pupils  Slows heart rate & breathing  Reactivates digestion & excretion  Also responsible for most of the ordinary, day-to-day bodily functioning

PART THREE The Biological Bases: The Endocrine System DEFINITION: A system that helps coordinate & integrate complex psychological reactions THE BODY’S SECONDARY COMMUNICATION

Biological Bases: Endocrine System Hormones  Chemical substances (similar in function to neurotransmitters) that help regulate bodily functions; released directly into the bloodstream by the endocrine glands  Fit into receptor sites on their target organs; affect behavior

Biological Bases: Endocrine System Pituitary Gland  Characteristics  Located just below the hypothalamus  Considered the “master” gland  Controls or influences ALL of the other endocrine glands  Hormones  Oxytocin Stimulates contractions of the uterus, production of milk, sexual behavior and pair bonding  Growth Hormone Promotes growth from infancy to adulthood

Biological Bases: Endocrine System Pineal Gland  Characteristics  Near the base of the cerebrum; back of the brain  Helps to regulate the sleep-wake cycle   Hormones  Melatonin Tracks day length & influences sleep patterns Disturbances in melatonin are responsible for “jet lag”

Biological Bases: Endocrine System Thyroid  Characteristics  Located inside the neck  Regulates metabolism  Hormones  Thyroxin Alertness & energy levels Weight  Hypothyroidism  Hyperthyroidism

Biological Bases: Endocrine System Pancreas  Characteristics  Located deep in the abdomen  Regulates blood-sugar  Hormones  Insulin Regulates carbohydrate & fat metabolism; lowers blood-sugar levels  Glucagon Raises blood-sugar levels

Biological Bases: Endocrine System Adrenal Glands  Characteristics  Located at the top of the kidneys  Secretes 30 different hormones to deal with stress, regulate salt intake, etc.  Hormones  Adrenaline (Epinephrine) Arouses the body in times of stress  Cortisol Helps manage stress, releases glucose into your bloodstream & increases blood pressure for increased physical activity

Biological Bases: Endocrine System Ovaries (gonads)  Estrogen  Responsible for the development and maintenance of female secondary sex characteristics Testes (gonads)  Testosterone  Principle male sex hormone