HUMAN PHYSIOLO
INTRODUCTION: FUNCTIONAL ORGANIZATION OF THE HUM
CELL STRUCTURE AND FU
,
, INTRODUCTION
• The goal of physiology is to explain the physical and chemical factors that are
responsible for the origin, development, and progression of life.
• In human physiology, we attempt to explain the specific characteristics and mech
of the human body that make it a living being.
• A large portion of the mechanisms that maintain life are beyond our control. Urg
as hunger, fear and feeling cold result in the search for food, safety and warmth.
• In this regard, humans can be defined as programmed beings, or automatons, an
fact that we are sensing, feeling, and knowledgeable beings is part of this autom
sequence of life; these special attributes allow us to exist under widely varying
conditions.
, • The basic living unit of the body is the cell. Each organ is an aggregate of many different c
together by intercellular supporting structures.
• Each type of cell is specially adapted to perform one or a few particular functions. For inst
red blood cells, numbering 25 trillion in each human being, transport oxygen from the lun
tissues and carbon dioxide from the tissues back to the lungs for expulsion.
• There are about 75 trillion additional cells of other types that perform functions different
those of the red cell. The entire body, then, contains about 100 trillion cells.
• Although the many cells of the body often differ markedly from one another, all of them h
certain basic characteristics that are alike. For instance, in all cells, oxygen reacts with
carbohydrate, fat, and protein to release the energy required for cell function.
• The general chemical mechanisms for changing nutrients into energy are basically the sam
cells, and all cells deliver end products of their chemical reactions into the surrounding flu
Almost all cells also have the ability to reproduce additional cells of their own kind.
• Fortunately, when cells of a particular type are destroyed from one cause or another, the
remaining cells of this type usually generate new cells until the supply is replenished.
INTRODUCTION: FUNCTIONAL ORGANIZATION OF THE HUM
CELL STRUCTURE AND FU
,
, INTRODUCTION
• The goal of physiology is to explain the physical and chemical factors that are
responsible for the origin, development, and progression of life.
• In human physiology, we attempt to explain the specific characteristics and mech
of the human body that make it a living being.
• A large portion of the mechanisms that maintain life are beyond our control. Urg
as hunger, fear and feeling cold result in the search for food, safety and warmth.
• In this regard, humans can be defined as programmed beings, or automatons, an
fact that we are sensing, feeling, and knowledgeable beings is part of this autom
sequence of life; these special attributes allow us to exist under widely varying
conditions.
, • The basic living unit of the body is the cell. Each organ is an aggregate of many different c
together by intercellular supporting structures.
• Each type of cell is specially adapted to perform one or a few particular functions. For inst
red blood cells, numbering 25 trillion in each human being, transport oxygen from the lun
tissues and carbon dioxide from the tissues back to the lungs for expulsion.
• There are about 75 trillion additional cells of other types that perform functions different
those of the red cell. The entire body, then, contains about 100 trillion cells.
• Although the many cells of the body often differ markedly from one another, all of them h
certain basic characteristics that are alike. For instance, in all cells, oxygen reacts with
carbohydrate, fat, and protein to release the energy required for cell function.
• The general chemical mechanisms for changing nutrients into energy are basically the sam
cells, and all cells deliver end products of their chemical reactions into the surrounding flu
Almost all cells also have the ability to reproduce additional cells of their own kind.
• Fortunately, when cells of a particular type are destroyed from one cause or another, the
remaining cells of this type usually generate new cells until the supply is replenished.
