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Smooth muscle

Introduction Like skeletal muscle (see Ch. 5 ), the primary function of smooth muscle is contraction. However, although skeletal muscles often attach to bones and cross joints so that contraction produces limb movement, smooth muscle typically forms tissues within organ systems (e.g., vascular, respiratory, gastro-intestinal [GI]) to regulate the movement of liquids (blood), gases (air), and/or solids (food) within hollow tubular structures (e.g., blood vessels, bronchi,…

The neuromuscular junction and skeletal muscle

Introduction Muscle comes in three varieties: 1. Cardiac 2. Skeletal 3. Smooth These three types are differentiated based on: 1. Distinct control systems (neuronal, neurohormonal) 2. Anatomic locations 3. Specialized cellular structure, function, and biochemistry. The major function of skeletal muscle is its role as the effector organ in voluntary movement. It mediates transformation of central nervous system electrical activity into purposeful mechanical actions, such as…

Peripheral nervous system and autonomic nervous system

Introduction The peripheral nervous system (PNS) is the direct extension of the central nervous system (CNS), and it is capable of consciously monitoring and reacting to primarily external stimuli. Dysfunction of this system can lead to an inability of patients to consciously interact with their environment or to receive signals that do not accurately represent their environment. It can be broken down into two subsystems: 1.…

Central nervous system

Introduction Because of the development of new research techniques, knowledge of the brain acquired in the past 2 decades has exceeded the amount learned in all previous centuries. Numerous questions remain unanswered: “What is consciousness?” “What defines our personality?” “How can we learn better?” The central nervous system (CNS) is composed of the brain and spinal cord. Integrates information received from the body Coordinates and influences…

An overview of nerve cell physiology and electrophysiology

Introduction The nervous system actively participates in, regulates, and integrates all the other body systems. The nervous system is broadly divided into: The central nervous system (CNS) (see Ch. 3 ). Composed of brain and spinal cord. The peripheral nervous system (PNS) (see Ch. 4 ). Composed of the autonomic nervous system (ANS) and somatic nervous system. This chapter focuses on the structure and cellular physiology…

General principles of physiology

Foundations of homeostasis Life functions (e.g., growth and development, reproduction, breathing, cognition, movement, self-defense, and responses to environmental stress) require either the input of energy into the body or the transformation of energy from one form to a more useful form by the body. For anything to happen in an organism, there must be a force, an energy, or work in the form of some gradient—chemical,…

Case Based Problems Discussion

Chapter 1 : Organ Systems and Tissues 1. In human development the brain and the spinal cord are derived from a. endoderm b. ectoderm c. mesoderm d. yolk sac e. none of the above The correct answer is b 2. Oviducts and uterus are derived from a. myotome b. mesonephros c. Mullerian ducts d. endoderm e. all of the above The correct answer is c 3.…

Blood and Lymphatic System

Deep Vein Thrombosis The normal function of a blood clot is to increase wound healing. However, when a clot is formed in a major blood vessel (often in the leg) unrelated to wound healing, it can be a major threat to life. Adventitious clot formation can occur when an individual spends long periods of time without movement, such as when sitting in a car or plane…

Vitamins and Nutrition

Vitamin D Deficiency There are many locations in North America and around the world where sunlight is limited. As many as half or more patients seen in clinical practice may be deficient in vitamin D, indicating the seriousness of this problem. Children growing up in a region with limited sunlight and remaining there as adults often prove to be vitamin D deficient and at risk for…

Micronutrients (Metals and Iodine)

Iron-deficiency Anemia Estimates by the World Health Organization are that 30% of the world’s population is anemic, and of these, half is due to the most common form of anemia, iron-deficiency anemia ( IDA ). IDA is the result of inadequate consumption of dietary iron. The diminished capacity of persons with IDA results in lowered efficiency of job performance, indirectly affecting the economy. IDA in children…

Membrane Transport

Cystic Fibrosis (Mucoviscidosis) and Aberrant Ion Transport A mutation in the gene for a chloride ion transporter gives rise to this disease. The transporter protein is called the cystic fibrosis transmembrane conductance regulator ( CFTR ). CFTR regulates the passage of chloride and sodium ions across epithelial membranes ( Fig. 18.1 ). A more realistic structure of the CFTR channel is shown in Fig. 18.2 .…

Growth Factors and Cytokines

Prospects for Cytokine Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand and Ovarian Cancer Among gynecological cancers , ovarian cancer causes more deaths than the others. One of the problems is that ovarian cancer is often diagnosed when it has already progressed to a late stage. Even when initial treatment seems successful, the cancer can reoccur and when this happens, the cancer is usually not curable. During a lifetime,…

Steroid Hormones

Steroid hormones play a major role in bodily functioning because they are required for many critical physiological processes, including survival of stress, injury (and illness), metabolism, inflammation, salt and water balance, immune functions, and development of sexual characteristics. Notably, the steroid hormone, cortisol , is required for adaptation (in particular, to stress and to changing environments) and human life is not possible in its absence. In…

Polypeptide Hormones

Panhypopituitarism: Malfunction of the Hypothalamus–Pituitary–End Organ Axis The pituitary is the source of several hormones that control many essential terminal hormonal functions. These include signals from the anterior pituitary that governs the stress hormone, cortisol from the adrenal cortex, the thyroid hormone from the thyroid gland, growth hormone (GH) from the anterior pituitary, sex hormones from the gonads of both male and female, the reabsorption of…