Respiratory System /biology/the-human- body/respiratory-system

Respiratory System

http://www.brightstorm.com/science/biology/the-human-body/respiratory-system

/

Respiration

• The exchange of gases between the body and the outside air– Oxygen is drawn in and delivered to the cells– Carbon dioxide is released

Organs of the Respiratory System

http://www.youtube.com/watch?v=HiT621PrrO0

Journey of a Breath of Air

• Ventilation – moving air into and out of the lungs– Nose and Mouth• Mucus and hairs trap any particles in the air• Air is warmed and moistened

– Pharynx – Long tube that is shared with the digestive system (esophagus)• Epiglottis closes when you swallow

– Larynx – voice box (vocal cords)

Journey of a Breath of Air

• Trachea – wind pipe– Leads into the chest– Divides into right and left bronchi• Contain cartilage which keeps them from collapsing• Mucus traps any remaining particles

– Tiny hairs help move the mucus and particles to where they can be expelled through the throat

• Air passes from the Bronchi to the smaller passages called the bronchioles

Pulmonary Gas Exchange

• Takes places in the alveoli of the lungs• http://www.youtube.com/watch?v=Z1h29R82

mVc&NR=1

Gas Transport

• Oxygen is carried from the lungs back to the heart by the circulatory system

Peripheral Gas Exchange

• Oxygen diffuses into the cells from the capillaries and carbon dioxide diffuses into the capillaries from the cells

Gas Exchange and Homeostasis

• Some of the carbon dioxide dissolves in the blood and forms carbonic acid to control the pH of the blood– This can get out of whack if we breathe too fast or

two slow• As a result breathing must be regulated

How does Breathing Occur?

• Comes from the contraction of the diaphragm

http://www.youtube.com/watch?v=hp-gCvW8PRY&feature=related

Control of Breathing

• Controlled by the brain stem– Uses the autonomic nervous system– Brain stem monitors the level of carbon dioxide in

the blood• If too high – signals diaphragm to contract more often

to get rid of excess carbon dioxide• If too low – the opposite

Diseases of the Respiratory System

• Asthma – air passages become too narrow and too much mucus– Triggered by allergens, strenuous activity, stress– http://www.youtube.com/watch?v=S04dci7NTPk&

#38;feature=reated• Pneumonia – alveoli fill with fluid– Coughing, chest pain, difficulty breathing• Infection or injury

– Bacterial or viral in nature

Diseases of the Respiratory System

• Emphysema – walls of the alveoli break down so less gas can be exchanged– Shortness of breath– Usually caused by

smoking and is irreversible

Cigarette Health Warnings

• Larger more prominent warning in September of 2012• Cigarettes are addictive• Tobacco smoke can harm your children• Cigarettes cause fatal lung disease• Cigarettes cause strokes and heart disease• Smoking during pregnancy can harm your baby• Smoking can kill you• Tobacco smoke causes fatal lung disease in nonsmokers• Quitting smoking now greatly reduces serious risks to your

health• http://www.fda.gov/TobaccoProducts/Labeling/Labeling/Cigar

etteWarningLabels/default.htm

The Digestive System

http://www.brightstorm.com/science/biology/the-human-body/digestive-system/

Overview

The GI Tract

• Connects mouth to the anus• 30 feet long in adults• http://www.youtube.com/watch?v=QtDgQjO

GPJM• Lined with mucus membranes that secrete

digestive enzymes and absorb nutrients• Peristalsis is the involuntary muscle

contractions that move food along in waves• http://en.wikipedia.org/wiki/File:Peristalsis.gif

Accessory Organs of Digestion

• Food does not pass through them• They secrete or store substances needed

digestion– Liver– Pancreas– Gall Bladder

Functions of the Digestive System

• Mechanical digestion– Physical breakdown of chunks of food– Takes place in the mouth and stomach

• Chemical digestion– Chemical breakdown of food into usable smaller nutrients

that can be absorbed by the blood• Begins in the mouth and stomach, but takes place mainly in the

small intestine

• Absorption – nutrients absorbed in the small intestine• Elimination – getting rid of the waste products

Digestion as a process

• Mouth to Stomach– Digestive enzymes released by the salivary glands

in the mouth (chemical)• Salivary amylase – starch into sugar

– Mechanical digestions– Food passes into the esophagus and then into the

stomach• Sphincter controls the entrance of food into the

stomach and from moving back up

Stomach

• Chemical and physical digestion• http://www.youtube.com/watch?v=URHBBE3

RKEs&feature=related• HCl– Kills bacteria in food and give the stomach a low

pH needed by the digestive enzymes to work• Pepsin – digests protein

– Sphincter opens and partially digested food moves into the small intestine

Digestion and Absorption in the Small Intestine

• 23 feet long in adults– Duodenum – smallest part – most chemical

digestion takes place here– Jejunum– Ileum

Digestive enzymes of the Duodenum

Enzyme What it Digests Where It is Made

Amylase Carbohydrates Pancreas

Trypsin Proteins Pancreas

Lipase Lipids Pancreas, Duodenum

Maltase Carbohydrates Duodenum

Peptidase Proteins Duodenum

Liver and Gall Bladder

• Liver– Produces bile which goes into the duodenum and

the gall bladder• Gall bladder– Concentrates and stores bile and then secretes it

into the small intestine– Bile breaks up globules of lipids– Enzymes here need a neutral environment• Created by the pancreas secreting bicarbonate

Absorption in the small intestine

• In jejunum by villi (many capillaries)

http://www.youtube.com/watch?v=P1sDOJM65Bc&feature=related

Large Intestine

• Cecum• Colon – Excess water is absorbed here• Rectum• Solid waste eliminated as feces• http://www.youtube.com/watch?v=Uzl6M1Yl

U3w&feature=related

The Excretory System

Excretion

• The large intestine eliminates solid wastes that remain after the digestion of food

• The liver breaks down excess amino acids and toxins in the blood

• The skin eliminates excess water and salts in sweat

• The lungs exhale water vapor and carbon dioxide

Kidneys

• The main organ of the excretory system

• Filters blood to form urine

• Nephrons are the structural and functional units of the kidney– There are more than a

million nephronshttp://www.youtube.com/watch?v=cc8sUv2SuaY&lr=1

Filtering blood and forming urine

• Blood enters through the renal artery and branches into the capillaries– Blood pressure forces some of the water and dissolved

substances to enter the Bowman’s capsule• Filtered substances pass to the renal tube

– Some substances are reabsorbed and returned to the bloodstream – other substances are secreted into the fluid

• Fluid passes through a collecting duct which reabsorbs some water and returns it to the bloodstream

• Rest remains in the collecting duct as urine

Excretion of Urine

• Urine enters the ureters– Peristalsis moves it to the bladder– When the bladder is about half full a signal is sent

to relax a sphincter muscle which allows the urine to flow into the urethra

– Urine passes out of the body through the urethra