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Levels of Organization and Organ Systems The human body is structured into ______. Recall that cells are the smallest units of life. Cells that are similar in _____ and _______ work together as _____. The human body has four primary kinds of tissue: Epithelial tissue – Connective tissue – Muscle tissue – Nervous tissue – Different types of tissues work together to form _________, which carry out particular functions. Examples include, ______, ______, ________ and _______. Organs cannot do all of the necessary work to sustain the body on their own. They must work together with other organs with related functions (____________) or structures (_________). This is referred to as an ________________. The following is a list of the body’s major organ systems and their functions: Organ System Major Organs Esophagus, stomach, intestines, liver, pancreas Heart, blood vessels Lungs, trachea, blood vessels Major Function Physical and chemical breakdown of food Transportation of nutrients, gases and waste; defence against infection Gas exchange Testes, vas deferns, ovaries, uterus, fallopian tubes Kidney, bladder, ureter, urethra Sexual reproduction Bones, muscles Movement of body and body parts Pancreas, pituitary gland, adrenal glands Brain, spinal cord, eyes, ears, nose, tongue, nerves Coordination and chemical regulation of body activities Response to environment; control of body activities Removal of waste What is Nutrition? Nutritional science is the study of _______ and ______________ found in foods that affect human _______ and ___________. A thorough understanding about nutrition enables people to make ___________________. A nutrient is an _____ _______ that is broken down by the body. Good nutrition is important because it: a) Provides the ________ we need to carry out all of our __________________. b) Provides us with the essential _____________ that we need as building blocks. There are three main categories of nutrients: 1. MACRONUTRIENTS (Macromolecules) Macromolecules are required by the body in _______ amounts. These molecules form the _________ and carry out the _______ of all cells. They are ________ molecules that may contain anywhere from _____ to ___________ of carbon atoms. Because of their _____ and the intricate ______ that macromolecules can assume, these large molecules are capable of performing a wide variety of complex ______ with great __________ and __________. Macromolecules are ___________ of smaller units (__________) linked together. There are four classes of macromolecules in cells: i. CARBOHYDRATES ii. LIPIDS iii. PROTEINS iv. NUCLEIC ACIDS (polymers of ___________) (polymers of _________________) (polymers of ______________) (polymers of ________________) Monomers are linked together by __________ bonds. _________ are responsible for the __________ and __________ of macromolecules. 2. MICRONUTRIENTS Micronutrients are needed by the body _______ amounts. There are two main classes of micronutrients: i. Mineral - an ________ substance (such as copper, iron, calcium or phosphorous) that is needed in all body structures in ________ amounts for various functions, such as the transmission of ___________ and ______ contractions; ___________________________, therefore must be supplied by _________ or __________________ ii. Vitamin – an ______ molecule that acts as a ______ for essential __________ in the body, such as converting fats and carbohydrates into energy; can be ______________ or ____________; ____________________________, therefore must be supplied by ______ or ___________ 3. Special Nutrient Water is the considered a special nutrient and is required by all living things. Water is the most abundant molecule in any cell (constitutes _________ of the human body). It functions to act as a carrier for ______________ inside (___________) and outside (___________) of the cell, and as a medium for ________________ (___________). It also functions as a _____________ between organs, tissues and individual cells. The following properties of water make life possible, as we know it: a) b) c) Remains ________ over wide range of temp (1C - 99C) _________ most substances involved in living processes such as _______, __________, _______, __________ and ___ Changes temperature gradually (_____________________) when heated or cooled so it protects cells from rapid temperature changes and therefore a stable environment A balanced diet should provide all essential vitamins and minerals. Supplements maybe required for those who are ill, planning to have children, recovering from injury, suffering from digestive problems or choose not to eat an optimal diet. Canada’s Food guide recommends the following daily servings for a balanced diet: Food Group Daily Servings Grain Vegetables and Fruit Milk Products or Substitutes Meat and Alternatives Macromolecules Carbohydrates A green plants ability to get energy from the Sun and turn ___ from the ____ into _____ (carbohydrates) is called ___________ and is represented by the chemical equation below: Therefore, all carbohydrates come from green plants. Carbohydrates are nutrients based on molecules of sugar; because of this they are called “___________” which means “_____”. All carbohydrates have the general formula C-H2O, in other words they are “carbon-hydrates”. The function of carbohydrates are to act as the _______________________ in cells as they pass through the process of ______ _______________, which is represented by the chemical equation below: In photosynthesis _________________ is used to produce energy rich ______ molecules (glucose). In respiration the ______ molecule (glucose) is broken down and releases ______ (in the form of ATP) for the cell to use. Two important organelles are specialized for energy conversion. 1. 2. There are two main varieties of carbohydrates that we consume, simple sugars such as monosaccharides (_______ and _______) or disaccharides (______ and ______), and ___________________ (_______ – ________ of sugar in __________). _______ is a carbohydrate that acts as a storehouse for _________ in _______. It is produced in the ____. Excess amounts of glycogen get converted into _____. Fibre is a carbohydrate (______) that cannot be _______ by humans. It helps to hold _______ and provide ______ in the large intestine, thus it helps to eliminate our waste. Current North American guidelines recommend that carbohydrates, especially ________ carbohydrates provide ____ to ____ of your daily energy requirements, which should be approximately ________. _______, ______ and _________ are excellent dietary sources of carbohydrates. When your diet is rich in carbohydrates, your body extracts energy from them, saving ________ for muscle building and body repair. Lipids Fats serve as a ________________________ along with providing insulation and acting as hormones. Current guidelines recommend that dietary fats should supply no more than ____ of your daily energy requirements. There are two main types of fat we consume, _______________ and ________________. Triglycerides are composed of a _______ molecule attached to ______________ chains. The fatty acid chain determines the type of triglyceride. A) Saturated Fatty Acids There are only single bonds between each carbon atom. This organization allows for a ____ arrangement of the fatty acid tails, allowing them to ____ close together, which explains why saturated fatty acids are _____ at room temperature. These are found in foods such as _____, _____, _______ and _____. Saturated fats are closely associated with __________. They can increase “bad cholesterol” (___) and decrease “good cholesterol” (___). B) Unsaturated Fatty Acids There is one (______________) or more (_____________) ______ bonds in the carbon chain. This means that not every carbon is bonded to its maximum number of hydrogen atoms. Double bonds produce _____ in the fatty acid chain, consequently, the more double bonds the chain possess, the greater the difficulty for these chains to pack together. This explains why unsaturated fats form ________ at room temperature (___). These are found in foods such as ___ or soft _______. Most naturally occurring unsaturated fatty acids are found in what is called the ___configuration. These types of fats appear to ______ total cholesterol levels. Unsaturated fats can have their double bonds chemically ________ with hydrogen atoms (a process termed ______________). During this process ______ fats are produced. The resulting molecule creates ________ chains, which are capable of being _______ at room temperature, such as _________. Trans-fats elevate ___ cholesterol levels and lowers ___ cholesterol levels. They are thought to be ___________ to human health. Omega-__ and omega-__ fatty acids are essential fats found in ___, ______, ___ and ______________ that are required to build ______, the protective covering around __________ of our ________ cells. There are two types of cholesterol; about ____ of cholesterol is made by our ___, while the other ____ comes from _______: 1. Dietary Cholesterol Found in foods containing animal fat - _____________________ _________________________ Doesn’t normally cause blood cholesterol to ___________ in most people 2. Blood Cholesterol Most of this cholesterol is produced by the ________ Two types - HDL and LDL HDL (good) - High-Density Lipoprotein Contains less lipids and more proteins Helps ________________________ from body To boost HDL - _______, be _________ and maintain ________________ LDL (bad) - Low-Density Lipoprotein Contains more lipids and less proteins Clogs arteries because these are deposited on artery walls (______), blocks circulation, increases risk of ______________ or ________ To lower LDL - cut down on ____________ and _____ fats, eat more foods containing soluble ________ Proteins Account for _____ of the dry weight of cells Wide variety of _______ in organisms – _______________________etc… Huge variety of _________ - each protein has a unique _______________ _______ Always assembled from a common cellular pool of _________________ __ of the 20 amino acids are considered ______ amino acids as they cannot be produced by the body, but must be obtained through _____ Proteins should make-up __________ of daily energy requirements Animals sources such as ___________________ and ______ are sources of ___________ proteins (provide all 8 of the essential amino acids) _______________ and __________ are ____________ proteins, because they do not provide all the essential amino acids Vegetarians attempt to avoid all meat products, although may consume dairy and egg products. Vegans will restrict their diet to foods derived from plants Vegetarians and vegans must carefully balance their food intake in order to obtain all eight essential amino acids An amino acid is composed of a ______ atom (called the _____ carbon) ________ bonded to four different groups: Types of Digestion All organisms must have some way of obtaining essential ________ needed to make their own structures and to perform life functions. Organisms that depend on organic molecules manufactured by other living things are called _____________. Digestion can occur _________ or _________. External digestion is thought to be the first type of system to evolve and organisms such as _______ and _______ still rely on it today. In this process, enzymes are ________ into the environment surrounding the organism, where they break down organic material and then some of the products ____________ (move from an area of _____ concentration to ____ concentration) back to the organism. Internal digestion evolved later, where animals make use of a ______ system to digests organic material ______ of their body. This method is more efficient as it allows organisms to _______ and _______ their food and _______ and _______ the environments more effectively for the digestive process. Digestion can also be considered as ___________ or ___________. Intracellular digestion is the type of digestion in which food particles are taken ____________ and subjected to the action of enzymes there. Extracellular digestion is the digestion of food occurring ______________________________ (as in the tube arrangement common in animals). Types of Digestive Systems There are three main types of digestive systems: 1. 2. 3. All of these systems follow the same four steps: Ingestion – Physical and Chemical – Breakdown Absorption – Egestion – 1. Vacuole System Food is digested inside a vacuole formed within the cell. Examples: _______________ and ___________ 2. Closed Tube System This type of digestive system consists of a “__________” structure with only ______________. Both ingestion and excretion occur through the same opening. In the digestive cavity, food is partially broken down by enzyme action and absorbed into cells lining the inside of the "bag". These cells complete the digestion process. Example: _____________ and a _____________ 3. Open Tube System This type of digestive system consists of a tube with ____ openings. One opening is used to ingest food particles and the other is used to excrete waste. Examples: ________ and ___________. Open tube systems usually require: 1. 2. Ingestion Digestion is a complex process, which results in food being broken down into its component molecules. It involves: 1) Mechanical (Physical) Digestion 2) Chemical Digestion In humans, the digestion process takes about ______ hours and requires passage through an extremely long tube system (_________________), separated into distinct regions that perform specific functions. Section Length The Mouth and Pharynx Both physical breakdown and chemical digestion occur in the mouth. The ______ and _______ are important for ______ digestion and the ______________ for ___________ digestion. Inside of your mouth, covering the surface of your tongue are tiny projections called _________, and every one holds hundreds of _____________. Taste is closely linked to _______ (smell); much of what we call the taste of food is actually the _________. Taste is a combination of sensations – ______, ______, ______ and ______. One theory is that taste buds for the different sensations are clustered in specific regions on the surface of the tongue. Can you figure out where these clusters are located? Sweet Sour Salty Human teeth Type of Tooth Incisor Canine Premolars Molars Wisdom Number Function Each tooth has two divisions, the ____ and an ___________. Enamel, which is formed of _______compounds, is the _________ substance in the body. Bitter A) How Chewing Helps Digestion? Sugar Appearance Before Loose Appearance After Cube B) How did the surface area of the types of sugar compare? C) How does surface area affect the rate of dissolving? Chemical digestion begins as food is chewed, and it begins to mix with _______ produced by the three salivary glands – ______, _______ and ____________. Some functions of saliva include: It wets and __________ so food can be swallowed easier and begins the _________ process (required for _______ and _____________) It causes the food particles to stick together to form a food mass, or _______ It contains a digestive enzyme called ______ (or ________________), which breaks down starch into simple carbohydrates The tongue pushes the food ____ to the back of the throat, and against the _______________, which initiates the automatic __________ reflex. The _________ prevents ____ and _______ from entering the ______ during swallowing, while the ______ stops food from entering the ________ cavity. The Esophagus No digestion, neither ______ nor _______ occurs in the esophagus. It secretes ________, a lubricant which aids the bolus of food in its journey to the stomach. The movement of food down the digestive tube is aided by _____________. Peristalsis consists of alternate waves of _________ and __________ in the muscular walls of the alimentary canal. Where the esophagus opens into the stomach, there is a ring of muscle called a __________. The ________________ acts as a valve and controls the passage of food from the __________ into the ___________. __________ or acid indigestion occurs when ____________ backs up into the esophagus, _______ its lining. Pain is felt in the region of the _____ where the esophagus is located, but the condition has nothing to do with the heart. The movement of food out of the stomach, up the esophagus and out the mouth is called _________________. The Stomach and Intestines Through the digestive process, macromolecules are broken down into molecules small enough to be ____________ from the intestine and transported to ______ cells: Carbohydrates Proteins Lipids (triglycerides) ___________ is the main process in which food is chemically broken down. During hydrolysis, a water molecule is added at the point where a _____ occurs between __________. Hydrolysis occurs at a very slow rate, but is immediately sped-up by ______________ (biological catalysts made of _____________). Enzymes are formed by _________ cells, which can exist ______, in ________ or in _______. A gland is a structure made up of a complex system of tubules connected to other areas by _______. Enzymes are very _________ and will only catalyze specific _________. Many enzymes require the presence of ________ or _______ in order to function properly. The Stomach The stomach is the site for temporarily storage of ____ and initial _____ digestion. Both ________ breakdown and _________ digestion occurs here. Physically the stomach has a ________ appearance and can hold up to _____ of food. Food is broken down mechanically into smaller particles by the _________ of the ________ stomach walls (______ muscles). This is referred to as __________. The food mass is churned and mixed with ______ juice secreted by two types of glands: 1. Pyloric glands Secrete _________, which covers the stomach lining and __________ it. 2. Gastric glands Secrete very _____ gastric juice, which has a pH of ___ to ___. Gastric juice contains hydrochloric acid (____) and the digestive enzyme __________. When pepsinogen is converted to its active form of ______, the breakdown of _______ into their individual _______________ begins. There are three mechanisms involved in stimulating the flow of gastric juice: 1. The _______________, or _____ of food stimulates the ____ to send messages via nerve impulses to the __________________. 2. Food ___________ the ___________ of the stomach. 3. Secretion of the hormone _______ caused by _________ of the ____________. Gastrin stimulates production of large amounts of _______________. In a typical day __ litres of fluid pass through the lumen of an adult’s gastrointestinal tract. Only about __ litres of that volume enters through the ____. The remaining __ litres come from body _________ secreted along with _________ and __________. A common disorder associated with the stomach occurs following the destruction of the ___________ in the stomach. This leads to a __________. Until recently, ____ and _____ were always thought to be the leading cause of ulcer formation. Scientists have now discovered a remarkable organism, ________________, which thrive in the stomach’s ____________ environment and are believed to cause most cases of ulcers. The Small Intestine Most chemical digestion and almost all absorption of nutrients occur here. After food leaves the stomach, regulated by the ________________, it enters the first part of the small intestine called the ________. At this stage, the partially digested food is called _______. The presence of chyme in the small intestine, stimulates secretion of the hormone _______ and ____________________. When these hormones reach the pancreas and liver they stimulate the production of _______________ and ____. The small intestine itself produces a number of enzymes that continue the chemical digestion process, such as: Secretes ______________ which completes the breakdown of ______________ Secretes ______________ which complete the breakdown of _____________ Peristaltic contraction continue throughout the intestines which has 3 main effects: 1. 2. 3. They ___________ chyme through the intestine moving the bolus along They _________ the chyme with digestive enzymes and break down food particles mechanically Bring the intestinal contents into contact with the intestinal wall speeding ______________ The Pancreas Produces ___________________ which ______________ stomach acid Secretes the digestive enzymes __________________________________ and _________________ Produces _________ and __________ in response to __________________ Insulin makes ________________ more _________ to ______ and __________ _______________ to _________ blood sugar levels Glucagon ________ blood sugar levels by stimulating the breakdown of ________ in the ___________ Insufficient insulin production can lead to ______________ The Liver Produces ______ – an _________ agent needed for the physical digestion of ___ Bile is stored in the ________________ Storage of _____________________ and ____________ (______________) _______________ many harmful substances (____________) Excessive damage to liver tissue can lead to the development of __________; a condition called _________________ Absorption During absorption, digested nutrients pass through _____________ and enter _________ or _____ in structures called ______. The capillaries act to absorb ___________________________ etc… into the ________ system. Lacteals are part of the __________________ and absorb ____________ and _______ into tiny vessels. The small intestine has a number of structural features that increase its surface area for maximum absorption of nutrients: 1. 2. 3. 4. The small intestine is very ________ Its lining has many _______ The lining is covered with millions of ________________ called ______, which increase the _______________ by as much as ______ times The epithelial cells of the villi that face into the intestinal opening have tiny projections called _____________ that further increase the surface area _______ disease is an ___________ disorder of the small intestine that occurs because of a reaction to _____ which is found in ____ products. Exposure to gluten causes the villi of the small intestine to ________. This interferes with the ____________ of nutrients and water causing ______________ and ___________________. _________ disease is a chronic ____________ disease of the intestines, primarily caused by ________ in the small and large intestines, but can affect the digestive system anywhere between the ____________ and the _________. The Large Intestine ____________ and _______________ materials pass from the small intestine into the large intestine. No digestion occurs in this portion of the digestive system. Functions of the large intestine include: 1. Reabsorption of _________ from the food mass 2. Absorption of vitamins __ and __ produced by live _____ in the large intestine 3. Elimination of undigested and indigestible material from the digestive tract (____) Examples: ________ from plant cell walls, large quantities of ________________ and __________________ from the digestive tract Fecal matter is stored in the last part of the large intestine, the ___________, and periodically eliminated, or ______________, through the _______.