Human Physiology, Biochemistry and Basic Medicine

Laurence A. Cole,Peter R. Kramer

• Editore: Academic Press
• Anno: 2015
• ISBN:
  9780128037171
• Argomento: Scienze biologiche
• Categoria: Biologia cellulare

Human Physiology, Biochemistry and Basic Medicine is a unique perspective that draws together human biology, physiology, biochemistry, nutrition, and cell biology in one comprehensive volume.

In this way, it is uniquely qualified to address the needs of the emerging field of humanology, a holistic approach to understanding the biology of humans and how they are distinguished from other animals.

Coverage starts with human anatomy and physiology and the details of the workings of all parts of the male and female body. Next, coverage of human biochemistry and how sugars, fats, and amino acids are made and digested is discussed, as is human basic medicine, covering the science of diseases and human evolution and pseudo-evolution.

The book concludes with coverage of basic human nutrition, diseases, and treatments, and contains broad coverage that will give the reader an understanding of the entire human picture.

• Covers the physiology, anatomy, nutrition, biochemistry and cell biology of humans, showing how they are distinguished from other animals
• Includes medical literature and internet references, example test questions, and a list of pertinent words at the end of each chapter
• Provides unique perspective into all aspects of what makes up and controls humans

1

Human Body Formed by Units

Introduction

Chapter 1.1

The Cell

Abstract

The cell is the base unit of all animals, plants (eukaryotic and prokaryotic), and other living beings. Cells are often thought of as the smallest unit of a living organism. A cell is made up of many even smaller parts, each with its own function. Human cells vary in size, but all are quite small. Even the largest cell, a fertilized egg, is too small to be seen with the naked eye. Inside each cell is a nucleus containing the signaling chromosomes; a mitochondrion or biochemical power supply where ATP is made; the rough endoplasmic reticulum where proteins are translated and produced; the golgi apparatus that processes proteins; the lysosome that degrades molecules; and multiple other apparatuses or organelles.

Keywords

Nucleus

Cytoplasm

Mitochondrion

Rough endoplasmic reticulum

Golgi apparatus

Lysosome

The cell is the unit of all animal and plant, prokaryotic and eukaryotic, life. There is single cell life like the amoeba, oligocell life like some plankton, and multicell life like humans. Humans actually contain 3.0 × 10¹³ cells or 30 trillion cells. If you imagine that an average speck of dust weighs just 0.75 μg, then the average 70 Kg man comprises the weight of 93 billion particles of dust. Considering both values, the average cell in the human body weighs just a tiny fraction of the mass of a speck of dust, 1/323 of a speck of dust. The cell is the basic human makeup or unit, a tiny fraction of a speck of dust.

This miniscule body, a fraction of the size of a speck of dust, is an entire village full of organelles or shops and business facilities. There is the mitochondrion, which is like the village power station, the nucleus, where the village mayor controls the village council or chromosomes and orders what is to be made and when, the rough endoplasmic reticulum and ribosomes, which are like the local village factory, hard at work manufacturing the village’s need for proteins, and the Golgi apparatus, another village factory, hard at work refining the synthesized proteins. Then there is the lysosomes or local village dump degrading the molecules not needed by the cells. All buildings in the village or fraction of a speck of dust work happily and eagerly together.

Figure 1.1.1 shows a representative human cell. While there are thousands of types or classes of cells in humans, each is different in shape, makeup, and function. A very general cell is shown in Figure 1.1.1. The number of each organelle varies in each cell type, and some cell types contain specialized functional organelles, which are not shown. Each cell is centered by a nucleus and within each cell is a nucleolus. Each cell has a smooth and rough endoplasmic reticulum, ribosomes, Golgi apparatus, mitochondria, lysosomes, centrioles, and microtubules. Shown are secretory vesicles emerging from the Golgi apparatus as a representative cell (Figure 1.1.1).

Figure 1.1.1 Representative animal cell and its organelles.

The Plasma Membrane

The plasma membrane is the envelope that encloses the entire cell. The envelope is made up of molecules called phospholipids. These are fatty acids with a charged or polar group on the head, and two long noncharged fatty tails comprising carbon and hydrogen atoms. Many different lengths of fatty acid tails, saturated and unsaturated carbon, and hydrogen atoms are found in phospholipids in different cell plasma membranes. One possible phospholipid with two stearic acid-derived fatty tails is shown in Figure 1.1.2.

Figure 1.1.2 The structure of phospholipids.

The phospholipids come together to form a bilayer, with the charged phospho groups on the extreme inside and outside of the membrane and the hydrophobic or noncharged fatty tails in the middle of the bilayer membrane. An example of a possible membrane is shown in Figure 1.1.3. The membrane is spanned by receptor proteins that bind a hormone or autocrine on the outside of the cell, and then transmit a protein signal to the inside of the cell. The bilayer is also crossed by channel protein, another type of protein that lets specific molecules, such as ions like Na⁺ enter, into the cell (Figure 1.1.3). The charged lipid bilayer blocks prote...