Biology is a course on human anatomy, designed for the Non-Biology major.
Functions of the Nervous System To carry out its normal role, the nervous system has three overlapping functions.
Much like a sentry, it uses its millions of sensory receptors to monitor changes occurring both inside and outside the body; these changes are called stimuli, and the gathered information is called sensory input.
Interpretation of sensory input. It processes and interprets the sensory input and decides what should be done at each moment, a process called integration. It then effects a response by activating muscles or glands effectors via motor output.
The brain is the center of mental activity, including consciousness, thinking, and memory. This function depends on the ability of the nervous system to detect, interpret, and respond to changes in the internal and external conditions.
It can help stimulate or inhibit the activities of other systems to help maintain a constant internal environment. Anatomy of the Nervous System The nervous system does not work alone to regulate and maintain body homeostasis; the endocrine system is a second important regulating system.
Organization of the Nervous System We only have one nervous system, but, because of its complexity, it is difficult to consider all of its parts Human anatomy and physiology final exam the same time; so, to simplify its study, we divide it in terms of its structures structural classification or in terms of its activities functional classification.
Structural Classification The structural classification, which includes all of the nervous system organs, has two subdivisions- the central nervous system and the peripheral nervous system. Central nervous system CNS. The CNS consists of the brain and spinal cordwhich occupy the dorsal body cavity and act as the integrating and command centers of the nervous system Peripheral nervous system PNS.
The PNS, the part of the nervous system outside the CNS, consists mainly of the nerves that extend from the brain and spinal cord.
Functional Classification The functional classification scheme is concerned only with PNS structures. The sensory, or afferent division, consists of nerves composed of nerve fibers that convey impulses to the central nervous system from sensory receptors located in various parts of the body.
Sensory fibers delivering impulses from the skin, skeletal muscles, and joints are called somatic sensory fibers. Those that transmit impulses from the visceral organs are called visceral sensory fibers. The motor, or efferent division carries impulses from the CNS to effector organs, the muscles and glands; the motor division has two subdivisions: The somatic nervous system allows us to consciously, or voluntarily, control our skeletal muscles.
The autonomic nervous system regulates events that are automatic, or involuntary; this subdivision, commonly called involuntary nervous system, has two parts: Structure and Function Even though it is complex, nervous tissue is made up of just two principal types of cells- supporting cells and neurons.
Neuroglia include many types of cells that generally support, insulate, and protect the delicate neurons; in addition, each of the different types of neuroglia, also simply called either glia or glial cells,has special functions.
These are abundant, star-shaped cells that account for nearly half of the neural tissue; astrocytes form a living barrier between the capillaries and neurons and play a role in making exchanges between the two so they could help protect neurons from harmful substances that might be in the blood.
These are spiderlike phagocytes that dispose of debris, including dead brain cells and bacteria.
Ependymal cells are glial cells that line the central cavities of the brain and the spinal cord; the beating of their cilia helps to circulate the cerebrospinal fluid that fills those cavities and forms a protective cushion around the CNS.
These are glia that wrap their flat extensions tightly around the nerve fibers, producing fatty insulating coverings called myelin sheaths. Schwann cells form the myelin sheaths around nerve fibers that are found in the PNS.
Satellite cells act as protective, cushioning cells. Neurons Neurons, also called nerve cells, are highly specialized to transmit messages nerve impulses from one part of the body to another. The cell body is the metabolic center of the neuron; it has a transparent nucleus with a conspicuous nucleolus; the rough ER, called Nissl substance, and neurofibrils are particularly abundant in the cell body.
The armlike processes, or fibers, vary in length from microscopic to 3 to 4 feet; dendrons convey incoming messages toward the cell body, while axons generate nerve impulses and typically conduct them away from the cell body. Neurons may have hundreds of the branching dendrites, depending on the neuron type, but each neuron has only one axon, which arises from a conelike region of the cell body called the axon hillock.
These terminals contain hundreds of tiny vesicles, or membranous sacs that contain neurotransmitters. Each axon terminal is separated from the next neuron by a tiny gap called synaptic cleft.
Most long nerve fibers are covered with a whitish, fatty material called myelin, which has a waxy appearance; myelin protects and insulates the fibers and increases the transmission rate of nerve impulses. Because the myelin sheath is formed by many individual Schwann cells, it has gaps, or indentations, called nodes of Ranvier.
Classification Neurons may be classified either according to how they function or according to their structure. Functional classification groups neurons according to the direction the nerve impulse is traveling relative to the CNS; on this basis, there are sensory, motor, and association neurons.Human Anatomy and Physiology This course explains the nature of matter and the principles of chemistry that are important to human physiology.
You will learn principles of genetics and gain an understanding of how traits are passed from one generation to the next. Human Anatomy & Physiology: Help and Review Final Free Practice Test Instructions Choose your answer to the question and click 'Continue' to see how you did.
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Anatomy and physiology quizzes (system quizzes) featuring interactive MCQs with the aid of animations, diagrams, and labeled illustrations.
Test your knowledge for free now! Human Anatomy and Physiology This course explains the nature of matter and the principles of chemistry that are important to human physiology. You will learn principles of genetics and gain an understanding of how traits are passed from one generation to .
Welcome to the Texas Board of Nursing Website. We welcome you to the Texas Board of Nursing (BON or Board) website. The BON has been serving the public for more than years since its establishment in by the Legislature to regulate the safe practice of nursing in Texas. Explore the human body online with ed2go’s Human Anatomy and Physiology course.
This course explains the nature of matter and the principles of chemistry that are important to human physiology. You will learn principles of genetics and gain an understanding of how traits are passed from one generation to the next.
The Final Exam will.