Digestion and Nutrition

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Digestion and Nutrition

• By Chaan Harris and Halainna Ramos

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Digestive System

• Digestion- the mechanical and chemical breakdown
  of foods and the absorption of the resulting
  nutrients by cells
• Digestive system-consists of the alimentary canal
• The alimentary system includes the mouth,
  pharynx, esophagus, stomach, small and large
  intestine, and anus extends about 8 meters from
  the mouth to the anus
• -The accessory organs include the salivary
  glands, liver, gallbladder, and pancreas

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Structure of the Wall

• The wall of the alimentary canal consists of four
  distinct layers that are developed to different
  degrees from region to region Mucosa, submucosa,
  muscular layer, and serosa/serous layer
• Mucosa/mucous membrane Surface epithelium,
  underlying connective tissue and a small amount
  of smooth muscle.
• Submucosa Consists of loose connective tissue as
  well as glands, blood vessels, lymphatic vessels,
  and nerves organized into a network called
  plexus.
• Muscular layer This layer produces movement of
  the tube. It consists of two coats of smooth
  muscle tissue and some nerves organized into a
  plexus. When the circular fibers contract, the
  tubes diameter decreases.
• Serosa/Serous layer The cells of the serosa
  protect the underlying tissues and secretes
  serous fluid.

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Movement

• The mouth receives food and begins digestion by
  mechanically reducing the size of solid particles
  and mixing them with saliva
• Cheeks and Lips
• The cheeks consist of outer layers of skin, pads
  of subcutaneous fat, muscles associated with
  expression and chewing.
• Lips surround the mouth opening
• Tongue
• The tongue nearly fills the oral cavity when the
  mouth is closed. Mucous membrane covers the
  tongue the membranous fold is called the
  frenulum which connects the midline of the tongue
  to the floor of the mouth.

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• The body of tongue is mostly skeletal muscle.
  These muscles mix food articles with saliva
  during chewing and move food toward the pharynx
  during swallowing.
• Rough projections called papillae on the tongue
  surface provide friction also bears taste buds.
• The posterior region, or the root of the tongue
  is anchored to the hyoid bode
• Palate
• The palate forms the roof of the oral canal
  cavity and consists of a hard anterior part and a
  soft posterior part.
• In the back of the mouth, on either side of the
  tongue and closely associated with the palate are
  masses of lymphatic tissue called palatine
  tonsils
• Teeth
• There are 2 different sets of teeth form during
  development.
• -The first set, the primary teeth usually erupt
  through the gums at regular intervals between the
  ages of six months and two to four years.

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Teeth

• Before the primary teeth shed, their roots are
  resorbed. The pressure from the developing
  secondary teeth push the primary teeth out of
  their sockets.
• Teeth begin mechanical digestion by breaking
  pieces of food into smaller pieces
• -This action increases the surface are of food
  particles, allowing digestive enzymes to react
  more effectively with the food molecules
• Each tooth consists of 2 main portions The crown
  and the root
• Glossy white enamel covers the crown. Enamel
  consists of mainly calcium salts and is the
  hardest substance in the body.

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Teeth cont.

• Dentin is a substance close to bone, but is much
  harder.
• Surrounds the tooths central cavity which
  contains a combination of blood vessels, nerves ,
  and connective tissue called pulp.
• Blood vessels and nerves reach this cavity
  through tubular root canals extending into the
  root
• A thin layer of bonelike material called cementum
  encloses the root. The periodontal ligament
  surrounds the cementum. This ligament contains
  bundles of thick collagenous fibers

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Salivary Glands

• The salivary glands secrete saliva. The fluid
  moistens food particles, helps bind them, and
  begins the chemical digestion of carbohydrates.
• Within a salivary gland are two types of
  secretory cells serous cells and mucous cells
• Serous cells produce watery fluid that contains
  that digestive enzyme amylse
• When a person sees, smells, or thinks,
  parasympathetic nerve impulses elicit the
  secretion of a large volume of watery saliva
• Paratial glands- are the largest of the major
  salivary glands.
• -Each gland lies anterior and somewhat inferior
  to the ear
• Sybmandibular glands- located on the floor of the
  mouth on the inside surface of the lower jaw

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Pharynx and Esophagus

• The pharynx connects the nasal and oral cavities
  with the larynx and esophagus. It has 3 parts
• Nasopharynx- communicates with the nasal cavity
  and provides a passageway for air during
  breathing
• Is posterior to the soft palate and inferior to
  the nasopharynx
• Laryngophanrynx is inferior to the orophyrnx
  pathway to the esophagus

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Swallowing Mechanism

• Food is mixed with saliva and forced into the
  pharynx
• Involuntary reflex actions force the food into
  the esophagus
• The soft palate raises, preventing food from
  entering the nasal cavity
• The hyoid bone and larynx is are elevated. The
  epiglottis blocks off the top of the larynx so
  the food doesnt enter the trachea
• Peristalis transports food to the stomach

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Stomach

• The stomach is divided into 4 parts Cardiac,
  fundic, body and pyloric regions
• -The cardiac region is a small area near the
  esophageal opening.
• The fundic region is a temporary storage area
• The body region is the main part of the stomach
  and lies between the fundic and pyloric portions
• The pyloric region narrows and becomes the
  pyloric canal as it approaches the small
  intestine

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Pancreas

• The pancreas produces pancreatic juice that is
  secreted into a pancreatic duct
• Pancreatic juice contains enzymes that split
  carbohydrates, proteins, lipids, and nucleic
  acids
• The carbohydrate digesting enzyme is pancreatic
  amylase, which splits the molecules of
  starch/glycogen into double sugars
• Pancreatic lipase is a fat digesting enzyme that
  breaks triglyceride molecules to fatty acids and
  glycerol
• Nucleases are enzymes that break down nucleic
  acid molecules into nucleotides
• Trypsin, chymotypsin and caboxypeptidase are
  protein splitting enzymes

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Liver

• The liver is located in the upper right quadrant
  of the abdominal cavity and is inferior to the
  diaphragm
• Functions metabolizes carbohydrates, lipids and
  proteins
• Filters blood
• Destroys toxins
• Secretes bile
• maintaining normal concentration of blood glucose
• transports fat to adipose tissue
• The gallbladder stores bile between meals

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Small/Large Intestine

• The small intestine is a tubular organ that
  extends from the pyloric sphincter to the
  beginning of the large intestine. fills most of
  the cavity
• Has 3 portions the duodenum, jejunum and the
  ileum

• The large intestine starts in the lower right
  side of the abdominal cavity where the ileum
  joins the cecum (beginning of intestine). It
  ascends to the right, crosses left, and descends
  into the pelvis
• It opens to the outside of the body as the anus
• The narrow tube with a closed end is called the
  vermiform appendix
• Fun Fact the human appendix has no known
  digestive function
• -It absorbs water and electrolytes and forms and
  stores feces

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Small/Large Intestine
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Vitamins/ Minerals

• Vitamins are organic compounds other than carbs,
  lipids and proteins
• - Fat-soluble vitamins are vitamins A, D, E and
  K water soluble are B and C
• Fat-soluble vitamins dissolve in fat which
  associates them with lipids and are influence by
  the same factors that affect lipid absorption
• -Fat-soluble vitamins can accumulate in various
  tissues and can lead to overdose conditions.
• Vitamin B help oxidize carbohydrates, lipids, and
  proteins Vitamin C promotes iron absorption
• Dietary minerals are essential in human
  metabolism
• Some minerals are part of inorganic compounds,
  like calcium phosphate of bone
• They play vital roles in nerve impulse
  production, muscle fiber contraction and
  maintenance of the pH of body fluids

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Carbohydrate, Lipid and Protein Digestion

• Carbohydrates are organic compounds used to
  supply energy for cellular processes
• They can be ingested in a variety of forms
  starch from grains and vegetables, glycogen from
  meats, disaccharides from cane sugar, and
  monosaccharides from honey and fruits.
• -Liver enzymes catalyze reactions that convert
  fructose and galactose into glucose, which is the
  carbohydrate form mostly used for cellular fuel
• Digestion breaks down complex carbohydrates into
  monosaccharides which are small enough to be
  absorbed
• Lipids include fats, oils and fatlike
  substances they supply energy for cellular
  processes
• Mostly found in meats, eggs, milk, nuts and lard
  (both plant- and animal-based foods)
• Proteins Supply energy after digestion breaks
  them down into amino acids they control
  metabolic rates, clotting factors,
  elastin/collagen of connective tissue
• Found in meats, fish, poultry, cheese/milk, eggs
  and cereals

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Healthy Diets

• An adequate diet provides sufficient energy,
  essential fatty acids, amino acids, vitamins and
  minerals to support growth and repair body tissue
• If a person lacks essential nutrients,
  malnutrition can be a result. This can be due to
  undernutrition (symptoms of deficiency diseases)
  or overnutrition (excess nutrient intake)
• Individual requirements for nutrients vary with
  age, sex, growth rate, amount of physical
  activity, and levels of stress.
• A measurement called body mass index, or BMI is
  used to determine whether a person is of adequate
  weight, overweight, or obese. Obesity rates are
  increasing in the U.S and raises the risk of
  developing cardiovascular disease, diabetes,
  and/or cancer
• Food pyramids are used to organize foods
  according to suggested amounts (serving size)

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Adequate Diet

• In order to have an adequate diet, an athlete
  would have to have a strict diet to follow.
• They would have to load up on carbohydrates (its
  the main source of energy)
• For muscle tone, eat about 5 oz. of proteins (but
  not too much it doesnt provide a lot of energy,
  but its good for building muscle tissue Calcium
  for bones (dairy)
• -For long events like marathons, athletes eat a
  lot of unsaturated fat from foods like nuts,
  vegetable oils and fatty fish.
• A person with a heart condition however, wont be
  able to eat the same foods, or the same amount as
  athletes.
• They are more likely to eat low-sodium canned
  vegetables and fruits
• Grains Whole-Wheat flour, High-fiber cereal,
  oatmeal, ground flaxseed and brown rice
• Proteins- Low-fat dairy products, egg whites,
  fish (mostly fatty, cold-water), skinless
  poultry, soybeans and soy products

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Diseases in the Digestive Sys.

• There are many types of diseases in the digestive
  system
• Anorexia nervosa- self starvation
• Cachexia-state of chronic malnutrition and
  physical wasting
• Cholelithiasis- inflammation of the gallbladder
• Dysphagia- Difficulty swallowing
• Enteritis- Inflammation of the intestine
• Gastrectomy- partial or complete removal of the
  stomach
• Glossitis- inflammation of the tongue
• Hyperalimentation- long-term intravenous
  nutrition
• Pharynatitis- inflammation of the pharynx
• Stomatitis- inflammation of the lining of the
  mouth

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Works Cited

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• Shier, David. Holes Essentials of Human Anatomy
  and Physiology. 9th Edition. Boston New York,
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• www.colgate.com/app.CP/US/EN/OC
• www.enchantedlearning.com/subjects/anatomy/digesti
  ve/labeleasy/
• En.wikipedia.org/wiki/Small _intestine
• www.everythingessential.me/HealthConcerns/Digestiv
  eDisorders.html
• Jaret, Peter. Top Nutrition Tips for Athletes.
  WebMD. June 17, 2012. WebMD.. Web. April 29,
  2014 http//www.webmd.com/fitness-exercise
• Mayo Clinic Staff. Heart-healthy diet 8 steps
  to prevent heart disease. 20 April 2014. Mayo
  Clinic. 20 April 20114. Web. lthttp//www.mayoclini
  c.org/diseases- conditionsgt
• www.pwsausa.org/syndrome/foodpyramid.htm
• www.sites.duke.edu/sofabkidsculinarycamp2013/
• www.washingtonpost.com/wp-srv/nation/daily/graphic
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