1. The Human Organism: Introduction to Human Body Systems PART 4
TPJ 3M
Nicole Klement
Source: bioEd on-line
Image Reference
LifeART. (1998). Super Anatomy Collection 1-9. Baltimore, MD: Williams & Wilkins, All rights reserved. 1

2. Human Organ Systems Skeletal Muscular Circulatory Immune Respiratory
Digestive
Excretory
Reproductive
Nervous
Endocrine
Integumentary
Human Organ Systems
Groups of organs working together to perform major activities of the body are called organ systems.
The skeletal system, made of bones, cartilage and joints, is the framework of the body. It protects internal organs, stores minerals and provides a place for muscles to attach.
The human muscular system is composed of smooth, cardiac and skeletal muscle tissue. Skeletal muscle, attached to the skeleton with dense strips of connective tissue called tendons, is responsible for the movement of body parts. Smooth muscle, sometimes called visceral muscle, is found in internal organs (eg, lines the walls of many blood vessels, makes up the iris of the eye and forms the wall of the gut). Cardiac muscle forms the bulk of the heart which controls blood circulation.
The circulatory system—blood, blood vessels and the heart—is the body’s transportation system, moving oxygen, carbon dioxide, nutrients, wastes, hormones, vitamins, minerals and water throughout the body. It also aids in regulation of temperature.
The digestive system converts foods to simple substances that can be absorbed and used by the cells of the body. It is composed of the mouth, pharynx, esophagus, stomach, small intestine and large intestine and is aided by several accessory organs (liver, gall bladder, and pancreas).
Made up of the skin, lungs, sweat glands and the kidneys, the excretory system removes metabolic wastes from the body. The kidneys are responsible for eliminating the bulk of wastes from the human body.
The reproductive system generates reproductive cells (gametes) and provides a mechanism for them to be fertilized and maintained until the developing embryo can survive outside the body. The primary reproductive organs are the ovaries (female) and the testes (male).
The nervous system regulates and coordinates the body’s responses to changes in the internal and external environment. Major structures of the nervous system are the brain, spinal cord and nerves.
The endocrine system consists of the hypothalamus, pituitary, thyroid, parathyroid and adrenal glands, as well as the pancreas, ovaries and testes. This system helps to maintain homeostasis, regulate temperature, and control growth, development, metabolism and reproduction by secreting and releasing hormones.
The first line of defense in protecting the body is the integumentary system, which is composed of the skin, hair, nails, sweat and oil glands. It protects against injury, infection and fluid loss and also aids in temperature regulation.
References
Campbell, N. E., & Reece, J. B. (2002). Biology (6th ed.). San Francisco: Benjamin Cummings.
Raven, P. H., & Johnson, G. B. (2002). Biology (6th ed.). McGraw-Hill. 2

3. The Human Digestive System Definition
Digestion converts food into simpler molecules that can be absorbed and used by the cells of the body
IN: Food and liquid
OUT:Water and undigested food
Human Digestive System
The 19th century German philosopher, Ludwig Feuerbach, said, “A man is what he eats.” Food fuels the body’s cells and is used as building material for repair and in some cases, is stored for future use. The purpose of digestion is to break food down to molecules that can be used by cells. Digestion involves three principle processes: mechanical digestion, chemical digestion and absorption.
The process begins in the mouth. Chewing initiates the mechanical breakdown of food and is followed by secretion of saliva, which moistens and lubricates food for swallowing. Saliva also contains amylases (enzymes), which start the chemical breakdown of carbohydrates.
The swallowing reflex begins in the pharynx and initiates rhythmic waves of smooth muscle contractions called peristalsis. Peristaltic contractions transport food to the stomach and allow a person to swallow even if he/she are upside down.
The stomach contains an extra layer of muscle that aids in mechanically mixing and churning food into a semi liquid form called “chyme.” Chemical digestion begins with proteins through the action of hydrochloric acid and the enzyme, pepsin. Only water and a few substances, such as aspirin and alcohol, are absorbed by the lining of the stomach.
As food enters the small intestine (so named because of diameter, not the length), secretions from the liver, gall bladder and pancreas are added. The small intestine completes digestion of food materials and the nutrients are absorbed into the blood. Fingerlike projections called villi (covered with microvilli) line the interior of the small intestine. Villi increase the surface area for absorption and secretion.
The large intestine is much shorter than the small intestine but is greater in diameter. The large intestine does not contain villi, which greatly reduces its available surface area for absorption. It has no role in digestion. Only water and vitamin K, synthesized by bacteria living in the the colon are absorbed into the bloodstream from the large intestine. Undigested or unabsorbed food is eliminated.
A nutrient is a substance the body needs for growth, repair and maintenance. Nutrients include carbohydrates, proteins, lipids, vitamins, minerals and water. Carbohydrates must be broken down into monosaccharides and are the body’s main source of energy. Proteins are broken down to amino acids and supply the raw materials for growth and repair. The body requires 20 amino acids, 10 of which it cannot make and must obtain from outside sources. Lipids are reduced to fatty acids and glycerin. They are used to make steroid hormones, cell membranes and also store energy. Vitamins are organic molecules that aid in the regulation of body processes. Finally, water is required for metabolism and chemical reactions within the body, for transport of substances around the body, and for regulation of body temperature. Approximately two-thirds of the body weight is water.
References
Campbell, N. E. & Reece, J. B. (2002). Biology (6th ed.). San Francisco: Benjamin Cummings.
Clark, J. O. E. (Ed.). (1989). A Visual Guide to the Human Body. Barnes & Noble Books.
Raven, P. H. & Johnson, G. B. (2002). Biology (6th ed.). McGraw-Hill.
Image Reference
LifeART. (1998). Super Anatomy Collection 1-9. Baltimore, MD: Williams & Wilkins, All rights reserved. 3

4. The Human Digestive System Function
To take in food, break it down, absorb its nutrients and expel wastes from the body

5. The Human Digestive System Structure
- made of a “tube” of varying widths that allows food to pass through
- also includes surrounding organs such as the liver, pancreas and gallbladder

6. The Human Digestive System Diagram
Villi
Mouth
Liver
Pharynx
Stomach
Large Intestine
Small Intestine
Esophagus
Structures (GI tract)
mouth,
pharynx,
esophagus,
stomach,
small intestine,
large intestine
Accessory
teeth,
tongue,
salivary glands,
liver,
gall bladder,
pancreas
Diagram of Human Digestive System
The digestive system includes the gastrointestinal tract (mouth, pharynx, esophagus, stomach, small and large intestines) along with accessory structures (teeth, tongue, salivary glands, liver, gall bladder and pancreas). Food materials are broken down to usable nutrients and absorbed into the bloodstream. They are used by the body for metabolism, building and repair. Some nutrients are stored within the body.
The lining of the small intestine consists of tiny folds, called villi, which, in turn, are covered by microvilli. Microvilli have brush border enzymes to hydrolyze lactose and sucrose. The villi contain capillaries and lymphatic vessels for the absorption of nutrients.
References
Campbell, N. E., & Reece, J. B. (2002). Biology (6th ed.). San Francisco: Benjamin Cummings.
Raven, P. H., & Johnson, G. B. (2002). Biology (6th ed.). McGraw-Hill.
Image Reference
LifeART. (1998). Super Anatomy Collection 1-9. Baltimore, MD: Williams & Wilkins, All rights reserved. 6

7. The Human Digestive System Digestive process
Through the digestive process macromolecules are broken down into their basic building blocks:
Carbohydrates  glucose
Proteins  amino acids
Fats  fatty acids and glycerol
now these molecule are small enough to be absorbed
vitamins and minerals are also absorbed

8. The Human Digestive System Four stages of food processing:
1. Ingestion: taking in of nutrients
2. Digestion: breaking down complex molecules into simpler molecules by physical and chemical means
3. Absorption: taking up of nutrients into the cells of the digestive tract
4. Egestion: removal of waste food materials from the body

9. The Human Digestive System Stage 1: Ingestion & Digestion - Mouth
Ingestion starts at the mouth
physical digestion or breakdown of food is done by the teeth:
incisors: blade-like for biting
canines: shred & tear
pre-molars & molars: grind & crush
chemical digestion of food is started amylase in your saliva
Tongue: pushes food back to the molars and forms a bolus (a moistened ball-like mass formed in the mouth to be swallowed)
Swallowing:
the tongue lifts the bolus to the roof of the mouth so that it can be swallowed.
the bolus goes through the pharynx (muscular tube connecting mouth to esophagus)
over the epiglottis (flap that prevents food from going into the trachea “the wrong tube” – to lungs)
into the esophagus
Peristalsis: smooth muscle movement that moves food along the esophagus

10. The Digestive System Stage 2: Digestion – the Stomach
Digestion- Stomach
both openings at the top and bottom of the stomach are guarded by circular muscles called sphincters
Ex: Sphincters Not working properly – acid reflux
hydrochloric acid and pepsin are secreted from the stomach lining lowering pH to pH2
Pepsin: used to digest protein
mucus lines the stomach to prevent it from digesting itself
the stomach churns the food as well
some absorption occurs in the stomach: water, some medicines (eg. Aspirin), and alcohol.

11. The Human Digestive System Stage 2: Digestion- The Small Intestine
Digestion – Small Intestine
7m in length, 2.5 cm in diameter
Duodenum: 1st section of the small intestine, 25 cm long; receives secretions from the pancreas and liver
Liver produces bile, which is secreted to the stomach. intestine, to digest fats
Liver also detoxifies the body by breaking down toxins like alcohol
Pancreas produces sodium bicarbonate to neutralize the acid from pH 2.5 to 9.0
Pancreas also enzymes to break down proteins, starches, lipids and nucleic acids.
Chyme: a porridge-like mixture of partly digested food, water and gastric juices

12. The Human Digestive System Stage 3: Absorption – Small and Large Intestines
Absorption- Small Intestine:
most absorption of nutrients occurs in the small intestine
small finger-like projections called villi on the intestine wall increase the surface area by tenfold
on the surface of each villi are microvilli which are fine, threadlike extensions of the membrane that further increase surface area
Diffusion and transport is affected by surface area
blood vessels in the villi take the nutrients to other parts of the body
Absorption - Large Intestine (aka the colon)
is 1.5m long and twice the diameter of the small intestine
absorbs minerals and water
hosts bacteria which produce vitamins K and B

13. The Human Digestive System Stage 4: Egestion
cellulose, or fibre, is the main component of feces (poo), along with bacteria and water
this fibre provides the feces with bulk and prevents constipation
as wastes build up receptors in the intestinal walls signal the central nervous system that wastes need to be voided
toxic wastes are thus excreted
if an individual does not eat enough fibre, they have fewer bowel movements and toxic wastes stay in the colon for longer
this can contribute to colon cancer

14. Human Organ Systems Skeletal Muscular Circulatory Immune Respiratory
Digestive
Excretory
Reproductive
Nervous
Endocrine
Integumentary

15. The Human Excretory System
Includes many systems such as digestive, respiratory, skin and urinary system.
Each gets rid of waste in its own way.

16. The Human Excretory System Urinary System
IN: Water and salts
OUT: Excess water, metabolic wastes & salts
Controls blood volume (blood pressure)
Works with hypothalmus to balance fluid levels in blood

17. The Human Excretory System Organs of Urinary System
Kidneys are bean shaped organs
Located at back of abdomen at at waist level
Kidney filters blood of waste products, creates waste product called urine

18. The Human Excretory System Kidneys
All of your blood is filtered through your kidneys in about 5 minutes.
Connected to bladder through two ducts called ureters
Drains urine into your bladder

19. The Human Excretory System Bladder
Bladder is where urine is held until you release it.
Bladder is an elastic, muscular organ that can stretch to hold 0.5 liter of urine.
Avg. human produces 1 liter of urine daily

20. The Human Excretory System Diseases of the Urinary System
A person can live normally with one kidney
If both kidneys fail, a person must use a dialysis machine to filter wastes out of the blood; or else you would die.

21. The Human Excretory System Skin
Part of excretory system
Salt and some organic substances out

22. MRI of Foods

23. Food
Twinkies
McDonalds Menu