The Human Organism:Introduction to Human Body SystemsPART 4

TPJ 3M

Nicole Klement

Source: bioEd on-line

Human Organ Systems

1. Skeletal2. Muscular3. Circulatory4. Immune5. Respiratory6. Digestive

7. Excretory8. Reproductive9. Nervous10. Endocrine11. Integumentary

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

The Human Digestive System Function

To take in food, break it down, absorb its nutrients and expel wastes from the body

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

The Human Digestive System Diagram

Structures (GI tract)1. mouth, 2. pharynx, 3. esophagus, 4. stomach, 5. small intestine, 6. large intestine

Accessory teeth, tongue, salivary glands, liver, gall bladder, pancreas

Villi

Mouth

Liver

Pharynx

StomachLarge Intestine

Small Intestine

Esophagus

The Human Digestive System Digestive process

Through the digestive process macromolecules are broken down into their basic building blocks:

Carbohydrates glucoseProteins amino acidsFats fatty acids and glycerol

now these molecule are small enough to be absorbed

vitamins and minerals are also absorbed

The Human Digestive System Four stages of food processing:

1. Ingestion: taking in of nutrients2. 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

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

The Digestive SystemStage 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.

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

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 bodyAbsorption - 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

The Human Digestive System Stage 4: Egestion

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

Human Organ Systems

1. Skeletal2. Muscular3. Circulatory4. Immune5. Respiratory6. Digestive

7. Excretory8. Reproductive9. Nervous10. Endocrine11. Integumentary

The Human Excretory System

Includes many systems such as digestive, respiratory, skin and urinary system.

Each gets rid of waste in its own way.

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

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

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

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

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.

The Human Excretory System Skin

Part of excretory system

Salt and some organic substances out

MRI of Foods

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Food

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