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By the end of this section, you will be able to:
  • Explain the importance of organization to the function of the human organism
  • Distinguish between metabolism, anabolism, and catabolism
  • Provide at least two examples of human responsiveness and human movement
  • Compare and contrast growth, differentiation, and reproduction

The different organ systems each have different functions and therefore unique roles to perform in physiology. These many functions can be summarized in terms of a few that we might consider definitive of human life: organization, metabolism, responsiveness, movement, development, and reproduction.

Organization

A human body consists of trillions of cells organized in a way that maintains distinct internal compartments. These compartments keep body cells separated from external environmental threats and keep the cells moist and nourished. They also separate internal body fluids from the countless microorganisms that grow on body surfaces, including the lining of certain tracts, or passageways. The intestinal tract, for example, is home to even more bacteria cells than the total of all human cells in the body, yet these bacteria are outside the body and cannot be allowed to circulate freely inside the body.

Cells, for example, have a cell membrane (also referred to as the plasma membrane) that keeps the intracellular environment—the fluids and organelles—separate from the extracellular environment. Blood vessels keep blood inside a closed circulatory system, and nerves and muscles are wrapped in connective tissue sheaths that separate them from surrounding structures. In the chest and abdomen, a variety of internal membranes keep major organs such as the lungs, heart, and kidneys separate from others.

The body’s largest organ system is the integumentary system, which includes the skin and its associated structures, such as hair and nails. The surface tissue of skin is a barrier that protects internal structures and fluids from potentially harmful microorganisms and other toxins.

Metabolism

The first law of thermodynamics holds that energy can neither be created nor destroyed—it can only change form. Your basic function as an organism is to consume (ingest) energy and molecules in the foods you eat, convert some of it into fuel for movement, sustain your body functions, and build and maintain your body structures. There are two types of reactions that accomplish this: anabolism    and catabolism    .

  • Anabolism is the process whereby smaller, simpler molecules are combined into larger, more complex substances. Your body can assemble, by utilizing energy, the complex chemicals it needs by combining small molecules derived from the foods you eat
  • Catabolism is the process by which larger more complex substances are broken down into smaller simpler molecules. Catabolism releases energy. The complex molecules found in foods are broken down so the body can use their parts to assemble the structures and substances needed for life.

Taken together, these two processes are called metabolism. Metabolism is the sum of all anabolic and catabolic reactions that take place in the body ( [link] ). Both anabolism and catabolism occur simultaneously and continuously to keep you alive.

Questions & Answers

difference between seminiferous tubules and ejaculatory duct
Muhammad Reply
tell me the answer boss
Musibi
wats dis group
Kity
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Agemo Reply
what is azygous vein
Karan Reply
Sir muscle contraction ka topic kis part m milega
sonugora Reply
Sir muscle contraction ka topic kis part m milega
sonugora Reply
what is manipulated
Ambika Reply
life circle of RBC and the life circle of WBC.
Yemi Reply
RBC 120days
Zeph
RBC 120days and WBC 10-12days
sai
what is cardiac vascular system
Hari
what is anatomy?
Md Reply
what is manipulated
Ambika
anatomy is the branch of medical science which deal with the gross structure of body or organ
Ambika
note shoulder joint
jagadeesh
what is cardiovascular system
Hari
what is manipulated
Ambika
anatomical position
Ambika
?
Ambika
Scapula
sonugora
Study of internal structures
sonugora
the system of heart and vessels
Manar
what is collar Bone?
jagadeesh
positive feedback mechanism
Sirimala Reply
what is immunology
Riya Reply
immunology is a branch of medicine that study's the body immune system
SAMUEL
Immunology This is the study of specific and non-specific resistance of the body against infection i.e. the study of the immune response of a host to a foreign substance, which includes study of various reactions which are induced in the body by introduction of a substance.
Kaluki
what is role of elimination need like fluid and also stools
Munmun Reply
bone
Vijay
what is joint pain
Vijay
is the physical suffering caused by illness or injury of the joint
malulu
pls can someone describe shock,types ,pathophysiology and treatment
Isaac
this is what I'm thinking "After taking out everything the body needs, the bowel then expels the leftover waste."
isaiah
I think elimination also helps in the continuation of the digestive system because if the unwanted fluids and stools does not come out of the system it can create a problem in the digestive. system resulting in diseases.
Martha
shock is a condition whereby the circulating system is unable to get enough blood and oxygen to vital organs like the brain,heart,eye,kidney and others.
Martha
causing depression of those organs.
Martha
there are 2 classification of shock. primary shock: this occurs immediately after injury due emotional stimulus or pain.example hearing a bad news,sudden obstruction of airway.sudden heart attack. secondary shock :it occurs when primary shock is delayed
Martha
types of shock syncope (faint) oligaemic or hyppvovaemic shock. Anaphylactic shock. neurogenic/ physical shock septic sock catdiogenic shock.
Martha
What is the difference between dna duplication and chromosomes duplication?
to help you identify the human body parts to help you live a healthy life the study of Anatomy helps one to work in any health sector
sophia Reply
okay.
what is the function of the mitochondrial in the cell
Vida Reply
define and explain the synovial membrane
Mahmudu Reply

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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