Systems of the Human Body

The study of the human body involves the interplay between the life science studies of anatomy and physiology. The human body uses many systems and mechanisms that interact in order to maintain homeostasis. Our Body: The Universe Within exhibits display the six primary systems in galleries.

Musculoskeletal System
Muscular

The human body contains more than 650 individual muscles that are attached to the skeleton and provides the pulling power for us to move around. The muscular system consists of three different types of muscle tissues: skeletal, cardiac and smooth. These different tissues have the ability to contract, which allows bodily movements and functions. There are two types of muscles in the system: involuntary and voluntary. Involuntary muscles are those that cannot be controlled and voluntary muscles are those that can be controlled. These muscles allow the human body to move efficiently and effectively.

The Skeletal system determines the shape of the body, protects its organs and works in association with the Muscular system. The Skeletal system is made up of bones, ligaments and tendons and acts as a protective device for the organs. It provides a firm base for muscles to attach to and enables us to move and function properly. Male and female skeletal structures are similar however, the female skeleton is a bit lighter, smaller and has a wider pelvis for birthing.

Skeletal
Head and Nervous System

The nervous system is comprised of bundles of fibers consisting of axons and neurons that are responsible for sending, receiving and processing impulses throughout the entire body and can be divided into two main systems.

The Central Nervous System -
The Peripheral Nervous System -
Respiratory System

The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to different parts of the body. The respiratory system does this via breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases is the respiratory system’s means of getting oxygen to our blood.

Is comprised of the brain and spinal cord, the central nervous system is responsible for issuing nerve impulses and analyzing sensory data.

Contains bundles of sensory and motor fibers that provide the nervous system with information about the environment via the five senses; sight, hearing, smell, taste and touch.

Respiration -

Is a chain of processes - from the inhalation of air, to the use of oxygen in the cells:

 

Oxygen enters the respiratory system through the mouth and the nose

 

The oxygen then passes through the larynx (where speech is produced) and the trachea, which is the tube that enters the chest cavity

In the chest cavity, the trachea splits into two smaller tubes called the bronchi; each bronchus then divides again, thus forming the bronchial tubes

The bronchial tubes head directly into the lungs where they divide into many smaller tubes that connect to tiny sacs called Alveoli - the average adult’s lungs contain approximately 600 million of these spongy, air-filled sacs that are surrounded by capillaries

The inhaled oxygen passes into the alveoli, and then diffuses through the capillaries into the arterial blood. At the same time, the waste-rich blood from the veins releases carbon dioxide gas into the alveoli. The carbon dioxide follows the same path out of the lungs when you exhale

The diaphragm is a sheet of muscles that lies across the bottom of the chest cavity. Its job is to help pump the carbon dioxide out the lungs and to pull oxygen into the lungs. As the diaphragm contracts and relaxes, breathing takes place. When the diaphragm contracts, oxygen is pulled into the lungs and when the diaphragm relaxes, carbon dioxide is pumped out of the lungs.

Digestive System

The Digestive System contains organs for changing the food we eat; a process that involves breaking food down into simple soluble substances absorbable by the tissues. 

 

The digestion process begins in your mouth when you begin chewing. The salivary glands produce secretions that are mixed with the food and saliva breaks down starches into dextrin and maltose.

 

The food goes down the esophagus in peristaltic waves until it reaches the stomach, which only takes a few seconds.

 

The stomach contains gastric juice which possesses chemicals such as hydrochloric acid as well as the enzymes pepsin, rennin, and lipase.

Another function of digestion in the stomach is to gradually release materials into the upper small intestine, where the digestion process is completed. 

 

After the solid food has been digested, the fluid that remains is called "chyme". The chyme passes through the pylorus sphincter and into the small intestine.

 

In the small intestine, all the nutrients are absorbed from the chyme into the bloodstream, leaving the rest as unusable residue. This residue passes through the colon or large intestine, into the rectum. The solid waste called "feces", then passes through the canal and anus.

Pepsin - breaks proteins into peptones and proteases

Rennin - separates milk into liquid and solid portions

Gastric Lipase - acts on lipids or fats

Urinary and Reproductive System

The major function of the reproductive system is to ensure survival of the species. Other systems in the body, such as the endocrine and urinary systems, work continuously to maintain homeostasis for survival of the individual. An individual may live a long, healthy, and happy life without producing offspring however,  if the species is to continue to perpetuate, some individuals must reproduce. Within the context of producing off-spring, the reproductive system has four functions: 

Produce egg and sperm cells

 

​Transport and sustain these cells

Nurture the developing offspring

Produce hormones that ensure the maturation of the reproductive system

​These functions are divided between two types of reproductive organs:

Primary Reproductive Organs - also referred to as gonads, consist of the ovaries and testes. These organs are responsible for producing the egg and sperm cells (gametes) and for producing hormones that enable the maturation of the reproductive system, the development of sexual characteristics, and have important roles in regulating the normal physiology of the reproductive system.

 

Secondary Reproductive Organs - also referred to as "accessory" reproductive organs, consist of ducts and glands that transport and sustain gametes and nurture the developing off-spring.

Female Reproductive System

The organs in this system produce and sustain the female sex cells (egg cells or ova), transport these cells to a site where they may be fertilized by sperm, provide a favorable environment for the developing fetus, move the fetus to the outside at the end of the development period, and produce female sex hormones. The female reproductive system includes the ovaries, fallopian tubes, uterus, vagina, accessory glands, and external genital organs. 

Male Reproductive System

 Like the female reproductive system, the male reproductive system consists of organs whose function is to produce a new individual/accomplish reproduction. The organs consist of a pair of testes, a network of excretory ducts: epididymis, ductus deferens, vas deferens, ejaculatory ducts, seminal vesicles, the prostate, the bulbourethral glands, and the penis. 

Cardiovascular System

The heart, lungs and blood vessels work together to form the cardiovascular or circulatory system. On average, the human body has approximately five liters of blood continually traveling through its circulatory system with the heart at the center of it all. The heart pumps oxygenated blood to the body and de-oxygenated blood to the lungs.

There are three fundamental systems within the cardiovascular system. Each of these systems must be working independently in order for all them to work together correctly:

The Pulmonary System -  pumps de-oxygenated blood from the heart to the lungs via the pulmonary artery and returns it to the heart once oxygenated, via the pulmonary vein 

 

The Coronary System - allows a steady supply of blood to reach the heart muscle

 

The Systemic System - distributes blood to the entire body (with the exception of the lungs)