Body Systems Overview

HST-2nd period

Integumentary System

The Integumentary System consists of the largest organ in the body, the skin. It protects the internal structures of the body from damage, prevents dehydration, stores fat and produces vitamins and hormones. It also helps to maintain homoestasis within the body by assisting in the regulation of body temperature and water balance. (sweating)

Their is three major layers to the skin:

  • Epidermis - outermost layer of the skin composed of squamous cells. This layer is characterized into two distinct types: thick skin and thin skin.
  • Dermis - thickest layer of skin that lies beneath and supports the epidermis.
  • Hypodermis (Subcutis) - innermost layer of the skin that helps to insulate the body and cushion internal organs.
  • Muscular System

    Function: to contract and relax, to cause movement by pulling on the bones. It also stabalizes body position, along with generating heat.

    Muscles are organs; their are approx. 700 muscles in the body and can make up 60lbs of a persons weight.

    The heart, or the cardiac muscle, is an example of involuntary muscle.

    Three major muscle groups:


    The cardiac muscles is the muscle of the heart itself. Its tissue makes up the wall of the heart called the mydocardium. The cardiac muscle is striated and contracts through the sliding filament method. It differs from other types of muscles because it forms branching fibers. Unlike the skeletal muscles, the cardiac muscle is attached together instead of been attach to a bone.


    The skeletal muscle makes up about 40 % of an adults body weight. It has stripe-like markings, or striations. The skeletal muscles is composed of long muscle fibers. Each of these muscles fiber is a cell which contains several nuclei. The nervous system controls the contraction of the muscle. Many of the skeletal muscle contractions are automatic. However we still can control the action of the skeletal muscle. And it is because of this reason that the skeletal muscle is also called voluntary muscle.


    Much of our internal organs is made up of smooth muscles. They are found in the urinary bladder, gallbladder, arteries, and veins. Also the digestive tract is made up of smooth muscle as well. The smooth muscles are controlled by the nervous system and hormones. We cannot consciously control the smooth muscle that is why they are often called involuntary muscles.

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    Reproductive System

    Female Composed of:


    Fallopian tubes




    Produces gametes (eggs)--Stores eggs-- Transports eggs-- produces hormones-- nourishes and supports developing fetus-- delievers a baby (approx. 9 months)

    Male Composed of:



    Ductus deferens



    Produce gametes(sperm)-- Stores sperm-- Transports sperm-- Delievers sperm-- Produces hormones