digestive system - life science with ms....
TRANSCRIPT
Chapter Introduction
How does the form of the digestive system help it with its function?
Lesson 1
• A Calorie (Cal) is the amount of energy it takes to raise the temperature of 1 kg of water by 1°C.
• All foods give your body energy to use.
• The amount of energy in food is measured in Kilocalories. This is 1000 calories.
Why do you eat?
Lesson 1
• The amount of energy a person needs depends on:
1. Activity level
2. Gender
3. Age
Why do you eat? (cont.)
Lesson 1
• The six groups of nutrients are proteins, carbohydrates, fats, vitamins, minerals, and water.
• Each nutrient has a different function in the body.
Groups of Nutrients
Lesson 1
Proteins are large molecules made from amino acids. They:
• relay signals between cells
• protect against disease
• provide support to cells
• and speed up chemical reactions
Groups of Nutrients (cont.)
Dorling Kindersley/Getty Images
Lesson 1
• Carbohydrates are commonly starches, sugars, or fibers.
• Pasta, bread and rice all contain lots of carbohydrates
Groups of Nutrients (cont.)
Lesson 1
• Fats, or lipids, provide energy and help your body absorb vitamins.
Groups of Nutrients (cont.)
Lesson 1
• Fats are a major part of the cell membrane and help insulate the body against cold temperatures.
• Fats are often classified as either saturated or unsaturated. Unsaturated is healthier.
• A diet high in saturated fats can increase levels of cholesterol, which can increase the risk of heart disease.
Groups of Nutrients (cont.)
Lesson 1
• So… you need fat. Just not too much of it!
Groups of Nutrients (cont.)
Lesson 1
• Vitamins are nutrients that are needed in small amounts for growth, regulating body functions, and preventing some disease.
• Minerals are inorganic nutrients—nutrients that do not contain carbon—which help the body regulate many chemical reactions.
Groups of Nutrients (cont.)
Lesson 1
Important Vitamins and Minerals
Vitamin What it does Where to get it
Vitamin A Healthy skin, immune
system, eyes
Milk, eggs, carrots,
sweet potatoes,
spinach, apricots,
peaches, papayas,
and mangos
Vitamin C Healthy bones and
gums, wound healing,
brain health
Citrus fruits,
strawberries, kiwi,
guava, peppers,
tomatoes, broccoli,
and spinach
Vitamin D Strengthens bones The sun and fish
Lesson 1
Important Vitamins and Minerals
Vitamin What it does Where to get it
Vitamin E Protects cells from
damage
vegetable oils, nuts,
and green leafy
vegetables and
avocados
Vitamin B (12 and 6) Nerve function and
healthy red blood cells
red meat, poultry, milk,
cheese, eggs,
spinach, bananas (lots
of foods)
Folate Needed to make DNA Beans, green leafy
vegetables,
asparagus, and
orange juice
Lesson 1
• Your body needs water for chemical reactions to occur.
• When lost water is not replaced, you can become dehydrated.
• So, drink water too!
Groups of Nutrients (cont.)
Lesson 1
Food labels help you determine the amount of protein, carbohydrates, fats, and other substances in food.
Healthy Eating (cont.)
Lesson 1
On your board write:
1. Food item
2. Serving size
3. Calories
4. Fat
5. Protein
6. 1 vitamin (if any)
7. On a scale of 1 to 5, how healthy is this food?
Healthy Eating (cont.)
Bell ringer: What are important nutrients your body needs? Where could you find them?
Digestive System
Lesson 2
• The food you eat goes through four steps—ingestion, digestion, absorption, and elimination.
• Ingestion is the act of eating, or putting food in your mouth.
• Digestion is the mechanical and chemical breakdown of food into small particles and molecules that your body can absorb and use.
Functions of the Digestive System
Lesson 2
• Nutrients and water in the food are absorbed as small molecules of digested food by cells of the digestive system.
• Undigested food is eliminated, with other wastes, from your body.
Functions of the Digestive System (cont.)
Lesson 2
• In mechanical digestion, food is physically broken down into smaller pieces.
• Mechanical digestion happens when you chew, mash, and grind food with your teeth and tongue.
Types of Digestion
• In chemical digestion, chemical reactions break down foods into small molecules.
Lesson 2
• Enzymes are proteins that help break down larger molecules into smaller molecules.
• Enzymes also speed up, or catalyze, the rate of chemical reactions.
• The digestive system produces enzymes that are specialized to help break down each type of food molecule.
Types of Digestion (cont.)
Lesson 2
• Your digestive system has two parts: the digestive tract and the other organs that help the body break down and absorb food.
• The digestive tract extends from the mouth to the anus and has different organs connected by tube-like structures.
Organs of the Digestive System
Lesson 2
• Mechanical digestion of food begins in your mouth.
• Your teeth and tongue mechanically digest food as you chew.
• Saliva contains an enzyme that helps break down carbohydrates and substances that neutralize acidic foods.
Mouth
Lesson 2
• The esophagus is a muscular tube that connects the mouth to the stomach.
• Food moves through the esophagus and the rest of the digestive tract by waves of contractions called peristalsis.
Esophagas
Lesson 2
Stomach
• The stomach is a large, hollow organ that temporarily stores food and aids in chemical digestion.
• The stomach contains acid that helps break down cells in food.
• Food mixes with the acid in the stomach to form a thin, watery liquid called chyme.
Lesson 2
• From the stomach, chyme is squirted into the small intestine
• The first part of the small intestine does more chemical digestion
• The remainder of the small intestine absorbs nutrients from food.
Small Intestine
Lesson 2
The folds of the small intestine are covered with fingerlike projections called villi. Villi provide lots of surface area for absorption.
Lesson 2
• The pancreas and the liver produce substances that help with chemical digestion.
• The liver produces bile which helps break down fats
• Bile is stored in the gall bladder until it is needed
Pancreas, Liver and Gallbladder
Lesson 2
• The pancreas makes other enzymes that break down food.
• Notably, the pancreas makes insulin which breaks down sugar. People who are diabetic do not make enough insulin to properly regulate their blood sugar
Pancreas, Liver and Gallbladder
Lesson 2
• Food not absorbed in the small intestine moves into the large intestine, also called the colon.
• Materials that pass through the large intestine are the waste products of digestion.
• The main job of the large intestine is to absorb the water from the chyme, so you don’t get dehydrated.
Large Intestine
Lesson 2
• Muscles in the rectum and anus control the release of semisolid waste, called feces.
• Thanks to the large intestine the feces is a solid mass
Anus and Rectum
Grab a marker and SILENTLY add
something. Mark things like villi too!
• A peptic ulcer is a sore in the lining of the small intestine
• The acid from the stomach can burn through this sore and if left untreated can cause serious problems
Peptic Ulcer
• Painkillers actually make these ulcers worse!
• The reason for these ulcers is usually a bacterial infection, so antibiotics usually treat it
• Smoking can cause ulcers and make them worse!
Peptic Ulcer
• Disorder that affects the large intestine
• Causes cramping, gas, diarrhea and constipation
• No long term damage and people with IBS learn to monitor their diet closely and control it
Irritable Bowel Syndrome
• Normally your stomach has a valve that shuts after food enters
• With acid reflux, this valve is leaky
Acid Reflux
• Symptoms include: chest pain, heartburn, burping, constant hiccups, nausea and vomiting
• Pregnancy, smoking and being overweight all increase the risk of acid reflux
• Usually can be treated with diet changes, but also antacids or medicines like Prilosec or Prevacid can help.
Acid Reflux
• Occurs when the appendix becomes infected and inflamed
• Causes severe pain in the lower right abdomen
• Doctors must remove the appendix before it ruptures
Appendicitis
• Long-term inflammation of any part of the digestive tract
• Crohn’s Disease causes pain, ulcers, cramping, fatigue and delayed or stunted development in children
• Crohn’s cannot be cured but it can be treated so symptoms go into remission
Crohn’s Disease
• Treatment of Crohn’s includes changing diet, steriods an anti-inflammatory drugs
• Sometimes immune suppressants can be used (since the body is attacking itself)
Crohn’s Disease
Lesson 3
• The excretory system collects and eliminates wastes from the body and regulates the level of fluid in the body.
• If waste is not removed, it will poison your body.
Functions of the Excretory System
Lesson 3
• The organs of the urinary system work together to process, transport, collect and excrete liquid waste.
• The organs of the urinary system include two kidneys, two ureters, the bladder, and the urethra.
Organs of the Urinary System
Lesson 3
• The bean-shaped organ that filters, or removes, wastes from blood is the kidney.
• The body has two kidneys
Organs of the Urinary System (cont.)
Photodisc/Getty Images
Lesson 3
Organs of the Urinary System (cont.)
Nephrons are networks of capillaries and small tubes, or tubules, in the kidneys, where filtration of blood occurs.
Lesson 3
• When blood is filtered, a fluid called urine is produced.
• Urine leaves each kidney through a tube called the ureter.
Organs of the Urinary System (cont.)
Lesson 3
• Both ureters drain into the bladder which is a muscular sac that holds urine.
• Urine leaves the bladder through a tube called the urethra
Organs of the Urinary System (cont.)
Lesson 3
• A UTI is an infection in which bacteria gets into the urinary tract
• It is a common problem that causes: burning when urination, pain, frequent urination, cloudy/ dark urine
• It is easily treated with antibiotics
Urinary Tract Infection
Lesson 3
• Kidney stones may form when calcium builds up in the kidneys.
• Kidney stones are small solids that cause severe pain when they move.
• Usually kidney stones are passed through
• Pain killers are prescribed
• Sometimes with large stones surgery is required.
Kidney Stones
Lesson 3
• Many things can cause kidney disease like high blood pressure, poison, diabetes or trauma
• Nephrons stop working to filter blood
• Symptoms are varied, but a person may feel “unwell”
• Only a blood test can show if kidney disease is happening
Kidney Disease
Lesson 3
• No cure
• Doctors want to slow the damage if possible
• If severe a person may need a kidney transplant
Kidney Disease
Lesson 3
• Bladder leakage aka the inability to “hold it”
• Usually older women are affected
• The muscle around the urethra gets weak
Urinary Incontinence