Introduction to Psychology

Introduction to Psychology of 97 many physiological and psychological functions, and the spinal cord, which enables reflective behavior and relays information to the brain from elsewhere in the body. Peripheral Nervous System- The peripheral nervous system contains all the neural structures that lie outside of the brain and the spinal cord. Its specialized neurons help carry out both the input functions that enable us to sense what is going on inside and outside our bodies, and the output functions that enable us to respond with our muscles and glands. The peripheral nervous system has two major divisions, the somatic nervous system and the autonomic nervous system. Somatic Nervous System- Consists of sensory neurons that are specialized to transmit messages from the eyes, ears, and other sensory receptors, and the motor neurons that send messages from the brain and spinal cord to the muscles that control voluntary movements. The somatic nervous system carries information from muscles, sense organs, and skin to the central nervous system, allowing the sensations of pressure, pain, and temperature, among other things. It also carries messages from the central nervous system to skeletal muscles, allowing for voluntary movement. Autonomic Nervous System- The body’s internal environment is regulated largely through the activities of the autonomic nervous system. The autonomic nervous system senses the body’s internal functions, and it controls the glands and the smooth (involuntary) muscles that form the heart, the blood vessels, and the lining of the stomach and intestines. The autonomic nervous system is largely concerned with involuntary functions, such as respiration, circulation, and digestion; it is involved in many aspects of motivation, emotional behavior, and stress responses. It consists of two subdivisions, the sympathetic and the parasympathetic nervous system. Sympathetic Nervous System- Has an activation or arousal function, and it tends to act as a total unit. The sympathetic nervous system prepares the body for action, also referred to as the fight-or-flight mode. Responses include quickening of the heart rate, widening of the arteries, and stimulation of the sweat glands. Parasympathetic Nervous System- Deactivates the systems mobilized by the sympathetic nervous system and is in operation during states of relaxation. Responses include decreased heart rate, breathing rate, and digestive functioning. Hormones- The endocrine system secretes hormones into the blood stream. These chemical messengers affect many bodily processes, including those associated with the central and autonomic nervous system. Melatonin- This hormone is secreted by the pineal gland, has a relaxing effect on the body and promotes a readiness for sleep. Oxytocin- Is a pituitary hormone that stimulates uterine contractions during childbirth and triggers lactation. © 2015 Achieve Page 24