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

The Biological Bases: Central Nervous System Part one 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

The Biological Bases: Peripheral Nervous System Part TWO 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

The Biological Bases: The Endocrine System Part THREE 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