Glycogen Storage Disease Type I, von Gierke Disease (and Others: At Least 11 Types of Glycogen Storage Disease) This disease occurs as a result of an inherited deficiency of an enzyme involved in the synthesis or breakdown of glycogen, the storage form of glucose. Glycogen is formed primarily in the liver and muscle and, secondarily, in many other tissues as well. There are a variety of…
Diabetes Diabetes was recognized as early as 1500 BCE. Diabetes is a disease in which glucose cannot be utilized properly. There are basically two types of diabetes. Type 1 diabetes occurs, typically in the young, when the β-cells of the pancreas have been destroyed (by viruses or autoimmunity or both) so that insulin secretion cannot take place when the glucose level in the blood is high.…
Diagnostic Enzymology The principle of diagnostic enzymology is that various disease conditions cause increased cell membrane permeability to macromolecules or outright lysis of the cell membrane that allow macromolecules, dissolved in the cytoplasm, to leak into the extracellular space and gain access to the bloodstream. This permits assay of enzyme activity directly (including immune reaction) that would identify abnormally high levels in blood. Some of these…
Prion Disease, A Disease of Protein Conformational Change The prion diseases in man are Creutzfeldt–Jakob, Gerstmann–Straussler–Scheinker syndrome, fatal familial insomnia, kuru, and Alpers syndrome. Creutzfeldt–Jakob disease (CJD) is of interest, especially in view of the outbreak in Britain of the mad cow disease (bovine spongiform encephalopathy). Other important prion diseases of animals are chronic wasting disease in mule deer and elk and scrapie in sheep. These…
Knowledge concerning water, pH, and buffers is basic for the study of biological systems. Some general features of receptors, channels, and pumps are critical to the understanding of cellular biochemistry because the human body is made up of separate organs and tissues, and for it to function, these parts of the body are interdependent and need to be able to communicate. Intercellular communication from one organ…
Cellular Trafficking in Alzheimer’s Disease According to the Alzheimer’s Association, it is estimated in 2014 that about 5.2 million Americans have Alzheimer’s disease (AD). Of these, about 200,000 are below the age of 65. It is projected that by 2050, unless there is a future effective treatment, there may be about 16 million individuals who are 65 or older who have AD. The annual death rate…
Treatment of the Injured Knee: Use of Stem Cells to Replace Damaged Cartilage In the human body the knee, as it supports the entire body weight, is susceptible not only to acute injury but also, in particular, to the development of chronic osteoarthritis. Osteoarthritis can be defined as the degeneration of joint cartilage and the bone beneath it, and it occurs in any joint, especially in…
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There are few stresses to which the body is exposed that approach the extreme stresses of heavy exercise. In fact, if some of the extremes of exercise were continued for even moderately prolonged periods, they might be lethal. Therefore, sports physiology is mainly a discussion of the ultimate limits to which several of the bodily mechanisms can be stressed. To give one simple example: In a…
A complete discussion of fetal development, physiology of the child immediately after birth, and growth and development through the early years of life lies within the province of formal courses in obstetrics and pediatrics. However, many physiological principles are peculiar to the infant, and this chapter discusses the more important of these principles. Growth and Development of the Fetus The placenta and fetal membranes initially develop…
In Chapter 81, Chapter 82 , the sexual functions of the male and female are described to the point of fertilization of the ovum. If the ovum becomes fertilized, a new sequence of events called gestation or pregnancy takes place, and the fertilized ovum eventually develops into a full-term fetus. The purpose of this chapter is to discuss the early stages of ovum development after fertilization…
Female reproductive functions can be divided into two major phases: (1) preparation of the female body for conception and pregnancy and (2) the period of pregnancy itself. This chapter is concerned with preparation of the female body for pregnancy, and Chapter 83 presents the physiology of pregnancy and childbirth. Physiologic Anatomy of the Female Sexual Organs Figures 82-1 and 82-2 show the principal organs of the…
Male reproductive functions can be divided into three major subdivisions: (1) formation of sperm—spermatogenesis; (2) performance of the male sexual act; and (3) regulation of male reproductive functions by the various hormones. Associated with these reproductive functions are the effects of the male sex hormones on the accessory sexual organs, cellular metabolism, growth, and other functions of the body. Physiological Anatomy of the Male Sexual Organs…
The physiology of calcium and phosphate metabolism, formation of bone and teeth, and regulation of vitamin D, parathyroid hormone (PTH), and calcitonin are all closely intertwined. The extracellular calcium ion concentration, for example, is determined by the interplay of calcium absorption from the intestine, renal excretion of calcium, and bone uptake and release of calcium, each of which is regulated by the hormones just noted. Because…
The pancreas, in addition to its digestive functions, secretes two major hormones, insulin and glucagon , that are crucial for normal regulation of glucose, lipid, and protein metabolism. Although the pancreas secretes other hormones, such as amylin, somatostatin, and pancreatic polypeptide, their functions are not as well established. The main purpose of this chapter is to discuss the physiological roles of insulin and glucagon and the…
The two adrenal glands, each of which weighs about 4 grams, lie at the superior poles of the two kidneys. As shown in Figure 78-1 , each gland is composed of two major parts, the adrenal medulla and the adrenal cortex. The adrenal medulla, the central 20% of the gland, is functionally related to the sympathetic nervous system; it secretes the hormones epinephrine and norepinephrine in…
The thyroid gland, located immediately below the larynx on each side of and anterior to the trachea, is one of the largest of the endocrine glands, normally weighing 15 to 20 grams in adults. The thyroid secretes two major metabolic hormones, thyroxine and triiodothyronine, commonly called T 4 and T 3 , respectively. Both of these hormones profoundly increase the metabolic rate of the body. Complete…
Pituitary Gland and its Relation to the Hypothalamus Anterior and Posterior Lobes of The Pituitary Gland The pituitary gland ( Figure 76-1 ), also called the hypophysis, is a small gland—about 1 centimeter in diameter and 0.5 to 1 gram in weight—that lies in the sella turcica, a bony cavity at the base of the skull—and is connected to the hypothalamus by the pituitary (or hypophysial…
Coordination of Body Functions by Chemical Messengers The multiple activities of the cells, tissues, and organs of the body are coordinated by the interplay of several types of chemical messenger systems: 1. Neurotransmitters are released by axon terminals of neurons into the synaptic junctions and act locally to control nerve cell functions. 2. Endocrine hormones are released by glands or specialized cells into the circulating blood…
Normal Body Temperatures Body Core Temperature and Skin Temperature The temperature of the deep tissues of the body—the “core” of the body—usually remains very constant, within ±1°F (±0.6°C), except when a person has a febrile illness. Indeed, a nude person can be exposed to temperatures as low as 55°F or as high as 130°F in dry air and still maintain an almost constant core temperature. The…