Digestive System
Why Eat?
Good nutrition means your body will perform better. Energy comes from the consumption of nutrients and provides building materials, allowing growth, development, and rebuilding injured and damaged cells.
What system plays a key role in delivering vital nutrients to every cell in the body?
Circulatory System
What does food provide?
Nutrients
What does chemicals provide?
The building blocks to build molecules, generate energy and assemble essential nutrients your body can't produce
Do endotherms or ectotherms require more energy?
Endotherms require more energy
What is energy measured in?
Joules
What is metabolism?
All chemical reactions that occur in a living organism to maintain life
What is Catabolism?
Reactions that break down large molecules into smaller ones.
What is Anabolism?
Reactions that build larger molecules from smaller ones using energy.
What is the Metabolic rate?
Rate at which the body turns stored energy into working energy
What is Metabolic rate affected by?
Size, Sex, Physical Activity, age, hereditary
What is BMR?
rate at which energy is used by an organism that is at rest
What does BMR stand for?
Basal Metabolic Rate
What is BMI?
Approximate measure of body fat according to height and weight
What does BMI stand for?
Basal Metabolic Index
What are the 6 nutrients?
Carbs, Protein, Lipids, Water, Vitamins and Minerals
What are Nutrients?
a substance that provides nourishment essential for growth and the maintenance of life
What are the 2 groups all food substances can be divided into?
Organic and Inorganic
What are Organic Foods?
Organic foods are produced from living organisms. They are Carbs, fats, proteins and vitamins
What are Inorganic Foods?
Food that comes from rocks, soil and the sea. These are minerals and water
What are macronutrients?
consumed in large amounts daily. These are carbs, fats and proteins.
What are Micronutrients?
Taken in small quantities. These are vitamins and minerals
What is Roughage?
an important part of a complete diet. Doesn't have any nutrients but helps in digestion
What are polysaccharides?
Complex Carbohydrates. Number of sugar molecules bonded together
What is Cellulose?
found in plant cell walls. Indigestible by animals. It is fibre. Can be digested by herbivores.
What are Carbohydrates?
Main source of energy. It is required for all bodily functions
What are Monosaccharides?
Simple sugars, ringed structures. Glucose, fructose and Galactose. It doesn't need to be digested or broken down—good sources of quick energy.
What are Disaccharides?
2 simple sugars linked. Lactose (milk, sugar) sucrose (table sugar). Must be broken down before being used as an energy source by the body.
What are Proteins?
Chains of amino acids. 12 can be made by body, 8 must be obtained by diet.
What are Proteins Function?
Helps to repair and build tissues withing the body
What are Lipids (fats)?
Concentrated source of energy. Protective layer around organs. Phospholipid layer of cell membrane. Protective layer under the skin.
What is the function of lipids?
Store energy, signalling, and acting as structural components of cell membrane
What is the difference between Unsaturated Fats and Saturated FAts?
Unsaturated are liquid at room temp and are considered to be good fats. (oil) Saturated fats are solid at room temp (butter)
What are essential fatty acids?
must be obtained by diet (omega 3's)
What are steroids?
lipids that are sex hormones
What are Fatty Acids?
Long chains of carbon atoms with an acid group at 1 end
what does monosaturated mean?
If a fatty acid chains one double bond, a kink forms which makes the molecules a liquid (cause they can't pack together as good)
What does polyunsaturated mean?
If more than one double bond is present, the fat is said to be polyunsaturated.
Why is water important?
Blood volume, keeps tissues moist, regulates body temp, dissolves nutrients
How much water should an average adult have daily? Why?
8 cups or 2L because it replaces that lost through urine, sweat, respiration
What are Minerals?
Elements that are required to build or repair.
Why are plants a good source?
Plants are good sources because they absorb minerals from the soil
What does Ca, P help with?
bone formation
what does Na help with?
Nerve impulses
what does Fe help with?
Blood components
What are vitamins?
Nutrients are required in small amounts. Most act as coenzymes
What vitamins are fat soluble?
A, D, E, K
What do fat-soluble vitamins mean?
They are stored in the body (can't be eliminated quickly). The Body can't create these.
What vitamins are Water soluable?
B, C
What are water-soluble vitamins?
Dissolve in water, eliminated quickly, excess released in urine. Must be replenished everyday
What does Malnutrition mean?
Related to eating disorders. Can lead to serious and possibly life-threatening medical complications.
What is Borborygmi?
Stomach Rumble. A rumbling or gurgling noise made by the movement of fluid and gas in the intestines
What are the 3 rules of cell theory
All living things are made up of 1 or more cells. The cells are the simplest unit of life. All cells come from pre-existing cells
What is the classification of living things?
Cell, Offspring, Waste, Growth, Energy, Respond, Lifespan
Internal Systems
Trillions of specialized cells work together to create tissues, which work together as organs, which work together as organ systems, which work together to keep you as an organism in homepstasis
What is homeostasis?
Ability to maintain a stable, constant, balanced internal condition in the body
What is the Key Idea?
Structure always matches Function
Levels of Organizations in Animals?
Organ Systems, Organs, Tissues, Cells, Organelle, Molecules, Atoms
What is the first level of body hierarchy?
Cellular level. Cells can perform all the necessary functions that define life.
What is the second level of body hierarchy?
When cells come together to perform a similar function. Tissues include specialized cells forming muscle, nerve and skin
What are the 4 main kinds of tissues in vertebrate bodies?
Connective, Epithelial, nervous, muscle
What does connective tissue do?
Connects, supports and blinds or separates other tissues or organs
What is epithelial tissue?
Line the cavities and surfaces of blood vessels and organs
What is the third level of organization?
Organ Level. Where certain tissues come together to perform a certain function. (Organs found in the digestive system include the stomach, liver and small intestines)
What is the fourth level of body hierarchy?
Organ System. Groups of several organs work together to perform vital body functions.
How do Organ Systems play a role in maintaining the internal environment?
Through homeostasis
What Organ Systems support and move the body?
Skeletal- bones, ligaments, cartilage. Muscular- skeletal, smooth and cardiac muscles
What organ systems protect the body?
Urinary- filters and excretes waste. (Control pH, and blood pressure) Integumentary- skin, hair, nails (protection, temperature, water) Immune and Lymphatic- infection, injury, and cancer
What organ system produces the next generation?
Reproductive- male and female
What happens if a body or organ system can't maintain homeostasis?
Can stop functioning or even die
What are the 4 steps of digestion?
Ingestion, Digestion, Absorbtion, Egestion
What happens in Ingestion?
Take in nutrients (food)
What happens in Digestion?
Breakdown of nutrients. Physically and Chemically.
What happens in Absorbtion?
transfer from digestive system to circulatory system (bloodstream)
What happens in Egestion?
Removal of waste (undigested food) material
What is your Gastrointestinal Tract (GI Tract)
Series of hollow organs joined in a long, twisting tube from mouth to anus
What do accessory organs do?
supply digestive enzymes that break up food to make transportation and absorption of nutrients easier
What are the accessory organs in GI Tract?
Pancreas, Liver, Gall Bladder (includes salivary glands)
What is the difference between chemical and Mechanical Digestion?
Chemical Digestion is the chemical breakdown by enzymes and water in saliva. Mechanical digestion is the physical breakdown of food
What do your incisors/canines do?
Grabbing and cutting foods
What are your molars used for?
Grinding and crushing foods
What are your salivary glands?
Secrete saliva, made up of enzymes and mucus
What do the enzymes in your salivary glands do?
They are chemicals that speed up reactions (Amylase)
What does Mucus in your salivary glands do?
Lubricates and helps you to swallow foods.
What is a bolus?
Food that has been mixed in the mouth and saliva
What is the importance of enzymes?
Enzymes speed up the chemical reactions that breakdown food into smaller, simpler molecules that can pass through cell membranes (Catalyst)
What are the 3 main types of enzymes?
Carbohydrates, Lipases and Proteinases
What are the parts of the mouth?
Soft Palate, Pharynx, Epiglottis
What is your soft palate?
top of mouth
What is your pharynx?
Back of throat
What is your epiglottis?
A flap that lowers on the windpipe to prevent food from going to the lungs. Important that it prevents food from going down into the lungs by mistake. Made up of tissue made of cartilage that prevents food from entering trachea
What are peristaltic contraction?
Waves of muscular movements move the bolus through the pharynx and esophagus towards the stomach
What is the process of swallowing?
The soft palate lifts up to seal off nasal passages, then the tongue pushes on the back of the mouth to prevent bolus from coming up. The larynx moves up and the epiglottis covers opening to airway
How does food move through the body?
Autonomic control from the brainstem. The tongue moves food around to speed physical and chemical digestion while forming a bolus that can be swallowed. The the epiglottis covers opening to the airway so food goes to the digestive tract, not lungs. Then the peristalsis creates waves of strong muscle contractions that push food along the digestive tract like toothpaste.
What is the esophagus?
A muscular tube with 2 layers of muscle. 1 layer is circular and the other is longitudinal. These layers contract and relax creating a wave-like motion called peristalsis which moves the food down to the stomach.
What is the stomach?
J shaped (Can hold up to 4L of food) Storage of food. chemical and physical digestion occurs here.
what are Sphincters?
'elastics' control the movement of food. Itv is found at both ends of the stomach.
What are the 4 layers of Sphincters?
Mucosa, Submucosa, Muscularis and Serosa
What is Ruggae?
Folds in the stomach that allow the stomach to expand so it can store up to 15L of food
What is Mucosa?
Highly folded, secretes Gastric JUice, replaced every 3 days
What is Submucosa?
Nerves (detects food, initiate gastrin release) Blood vessels
What is Muscularis?
Muscle contracts to churn and mix. Food + Gastric Juice = 'Chyme'
what is Serosa?
Holds stomach together Eliminates rubbing between organs
What happens during chemical digestion?
Mucus protect stomach from the acid. Gastric Acid: hydrochloric acid (pH 2.0-3.0) KIlls microorganisms. HCI activate enzyme- Pepsinogen (converted into pepsin which breaks down proteins into amino acids
What happens in the process of the Stomach?
Gastric Gases are secreted and consists of 3 substances (Hydrochloric ACid, Mucus, Pepsin, and Chyme)
What is Hyrdrochloruc acid?
Kills bacteria and makes acidic environment for enzymes pH of 2
What is Mucus?
Protects the lining of stomach
What is Pepsin?
An enzyme that breaks down protein. Some substances such as water, sugars, ions, and alcohol can be absorbed through the stomach lining
What is chyme?
Name given to the contents of the stomach (Made up fo water, gastric juices and partially digested food)
What is the liver?
Largest internal organ (size of a football) Removes and breaks down toxins in the blood. Breaks down old red blood cells and stores substances such as vitamins, and glycogen. Produces bile, antibodies and essential elements of the blood-clotting mechanism.
What is the bile duct?
Connects liver to gall bladder
What is the gall bladder?
Stores bile. Bile- emulsifies fats, breaking them down to droplets. (Micelles)
What is the Pancreas?
Secrete: 1. Pancreatic amalyse- enzyme; breaks carbs. 2. Trypsin- enzyme; protein digestion. 3. Lipase- enzyme; that breaks down lipids. 4. Secretin- hormone; stimulates release of NaHCOs (Sodium bicarbonate) to neutralize acidic chyme digestive rate 'regulator'
What is the Pancreatic Duct?
Connects pancreas to duodeum
What is the small intestine?
7m long. Has 3 sections; Duodeum, Jejunum and Illeum
What is the duodenum?
Trypsin is made in the pancreas into the duodenum. Enzymes are added, majority of digestion takes place.
What is the Jejunum?
Some digestion and absorption begins
What is Ileum?
majority of nutrients absorbed, enzymes from the pancreas and bile from the liver aid in digestion process
What is absorption?
Folds called villi increase surface area (10x) Each villi has microvilli for more absorption (500x) Capillaries (tiny blood vessels) absorb nutrients (Carbs, lipids, protein) to enter the bloodstream and deliver to cells. Vessels called lacteals allow fats to enter and go to the lymphatic system