The Nervous System

The nervous system receives, processes, and stores information and the central nervous system provides sensory information and the peripheral nervous system system provides sensory input and motor output.

The peripheral nervous system (PNS) has somatic and autonomic division while the autonomic division of the PNS has sympathetic and parasympathetic divisions.

Neurons are the communication cells of the nervous system and these generally consists of a cell body, several short extensions called dendrites, and long thin extensions called an axon.

The brain and spinal cord constitute the central nervous system and they are protected by bone, by three layers of connective tissues called meninges and by cerebral spinal fluid.

Reference:

Johnson, M. D. (2010). Human Biology: Concepts and Current Issues (5th ed.). San Francisco: Pearson Education.

The Respiratory System

This is where respiration takes place and respiration includes breathing, external respiration, internal respiration, and cellular respiration.

This is composed of the upper and lower respiratory tracts

Upper respiratory tracts are the nose and pharynx and these two places filters, warms, and humidifies the air that will go to the lungs.

The lower respiratory tract include the larynx, trachea, main bronchi, and the lungs and within the lungs, bronchi branch many times becoming smaller airways called bronchioles that end in air filled sacs called aveoli.

The surface area of the alveoli coupled with the thickness of the respiratory membrane, facilitate gas exchange with the pulmonary capillaries.

Reference:

Johnson, M. D. (2010). Human Biology: Concepts and Current Issues (5th ed.). San Francisco: Pearson Education.

The Immune System

Pathogens cause disease and these include bacteria, viruses fungi, protozoa, worms, and prions.

The lymphatic system consists of vessels, lymph nodes, the spleen, the thymus gland, ad the tonsils and they all help protect the body by fighting diseases.

Skin is an effective barrier to the entry of microorganisms, while tears, saliva, mucus, and earwax trap pr wash microorganisms away.  Digestive acid in the stomach kills many organisms while vomiting, defecation, and urination physically remove organisms after entry in the body.

Phagocytes surround and engulf microorganisms while natural killer cells kill their targets by releasing damaging chemicals.  Interferons are proteins that interfere with viral reproduction and other circulating proteins either kill or mark microorganisms for elimination.

Cells of the immune system can distinguish foreign and damaged cells from healthy cells by surface cell markers called MHC proteins that identify the cells as "self".  B cells produce antibodies against foreign antigens while T cells enhance the immune response and kill foreign cells directly.

Immune memory creates immunity and medical assistance like vaccines immunize the body n advance against a particular disease.

Here's a different approach to using an actual video game (called Final Fantasy XII) to teach about the immune systems.  I though it was entertaining, what do you think? Please comment.  Thank you.
http://www.youtube.com/watch?v=kskFjm1pKEs


Reference:

Johnson, M. D. (2010). Human Biology: Concepts and Current Issues (5th ed.). San Francisco: Pearson Education.

The Cardiovascular System

Components of the cardiovascular system:

Blood - the medium in which the body gets its energy, oxygen, and nutrients, it is a deep red color.

Blood vessels: arteries - transports oxygen rich blood (color of red) to the different areas of the body for use.

Blood vessels: veins - transports oxygen poor blood (color of blue) back to the heart where it goes to the lungs to be re-oxygenated and used again.

Blood vessels: capillaries - places of exchange of fluids and solutes with the interstitial fluid.

Heart - the pumping mechanism of the body, the organ that allows for blood to be pumped around the body with strong pressure.  The heart itslef has a mechanism of electroconductivity to ensure the heart pumps (contracts and then relaxes) blood.

Click on this youtube link to see how the blood circulates around the body with oxygen rich and oxygen poor blood. http://www.youtube.com/watch?v=D3ZDJgFDdk0

Reference:

Johnson, M. D. (2010). Human Biology: Concepts and Current Issues (5th ed.). San Francisco: Pearson Education.

The Muscular System

Muscles produce movement or generate tension by contracting (shortening in length).

Within a single muscle fiber there are thousands of contractile units called sarcomeres that are arranged end to end.

There are three types of muscles: skeletal, cardiac, and smooth muscles.

Skeletal muscles contact oinly when activated by their motor nerve.

Cardiac and smooth muscles do not attach to bones and can contract spontaneously and be influenced by nerves.

Cardiac muscles are only found in the heart and is the main force for blood to be pumped from the heart

Smooth muscles are found in the digestive tract, urinary tract, and some blood vessels.

Check out this video about how muscles work:

http://www.youtube.com/watch?v=ren_IQPOhJc




Reference:

Johnson, M. D. (2010). Human Biology: Concepts and Current Issues (5th ed.). San Francisco: Pearson Education.

The Skeletal System

The skeletal system is important in that it gives structure to the human body.  Without it, we would be a compilation of tissues that has no form at all, except maybe a blob.  It consists of connective tissues such as bones, ligaments, and cartilage and the bone itself is composed of cells and extracellular material, while ligaments which are composed of dense fibrous connective tissues attach the bones together (Johnson, 2010).  The cartilage forms intervertebral disks and lines the points of contact between the bones (Johnson, 2010).  Bone development begins in the embryo and mature bone undergo remodeling and repair throughout life (Johnson, 2010).  Bones can change shape over time depending on external factors they are exposed to such as stress, injury, or chemicals.  The skeleton protects, supports, and permits movement (Johnson, 2010). 

Reference:

Johnson, M. D. (2010). Human Biology: Concepts and Current Issues (5th ed.). San Francisco: Pearson Education.

(p.s. I can't seem to "tab" the reference and make it center and have correct citing of reference.)

Table of Contents

In this blog, I will write about the various systems in the human body and give quick summary information about them.  The human body consists of various systems and these are the skeletal, muscular, cardiovascular, immune, respiratory, nervous, endocrine, digestive, urinary, and reproductive system.  Each has their own individual fuction and major organ or organs that support it.  Here is a short clip from youtube that you may find informative with fun facts about the body systems.  They will be better explained later on . 

Here is the link from youtube:
http://www.youtube.com/watch?v=po8D290YF9o&feature=related