SCIENCE

• Digestion


  Process of breaking down food into simple substances
• Parts of the digestive system

  • Teeth
  • Tongue
  • Epiglottis
  • Esophagus/Gullet
  • Stomach
  • Small Intestine
  • Large Intestine
  • Liver
  • Gall Bladder
  • Pancreas
• Esophagus/Gullet

  • Secrete mucus
  • Moves food from the throat to the stomach using muscle movement called peristalsis
• Stomach

  • Mixes food with Digestive Juices that contain enzymes to break down Proteins and Lipids
  • Acid (HCl) in the stomach Kills Bacteria
  • Food found in the stomach is called Chyme
• Small Intestine

  • Lining of intestine walls has finger-like projections called villi, to increase surface area
  • The villi are covered in microvilli which further increases surface area for absorption
• Large Intestine

  • Accepts what small intestines don't absorb
  • Rectum (short term storage which holds feces before it is expelled)
  • Bacterial digestion
  • Ferment carbohydrates
  • Absorbs more water
  • Concentrate wastes
• Liver


  • Directly affects digestion by producing bile
  • Bile helps digest fat
  • Filters out toxins and waste including drugs and alcohol and poisons
• Gall Bladder


  • Stores bile from the liver, releases it into the small intestine
  • Fatty diets can cause gallstones
• Pancreas


  • Produces digestive enzymes to digest fats, carbohydrates and proteins
  • Regulates blood sugar by producing insulin
• Digestion

  1. Ingestion/feeding

  2. Mechanical (physical)

  3. Chemical

  4. Absorption

  5. Assimilation

  6. Elimination/Excretion
• Common symptoms of digestive system diseases

  • A change of bowel habits
  • Sudden weight loss
  • Severe abdominal pain
  • Blood in the stool
  • Heartburn and release of gas
• Diarrhea


  Digestive disorder occurs when the lining of the large intestine cannot maintain the usual level of water absorption
• Constipation


  Occurs when the peristalsis moves the stool in the colon too slowly
• Hepatitis


  Inflammation of the liver caused by excessive consumption of alcohol or a viral infection
• Gallstones


  Crystals formed by too much cholesterol, bile salts and calcium in the gall bladder
• Peptic Ulcer


  Open sores found in the esophagus, stomach, and duodenum of the small intestine
• Hemorrhoids


  Also known as piles, occurs when rectal veins are inflamed and enlarged after straining and eliminating hard stools
• Appendicitis


  Inflammation of the appendix which is caused by an obstruction such as hard mass feces, foreign body, or parasitic infection
• Undernutrition


  People who cannot afford to buy as much food to meet the basic daily nutrient needs may suffer from chronic undernutrition or hunger
• Over nutrition


  Occurs when a person consumes too much calories in food with little exercise thus become overweight or obese
• Anorexia


  Patient suffering from this disorder restrict their food and drink intake under dangerous level
• Bulimia

  An eating disorder characterized episodes of secretive excessive eating followed by self – induced vomiting, overuse of laxatives or excessive exercise
• Nutrients in food

  • Carbohydrates
  • Fiber
  • Proteins
  • Fats
• Nutrient Deficiency


  Occurs when your body doesn't get enough nutrients
• Cell Division


  The two major functions are to create body cells and to form gametes for sexual reproduction
• Mitosis


  A process of nuclear division wherein two genetically identical daughter cells with the same number of chromosomes as their parent cell are produced

  
• Karyotype


  Shows the number of chromosomes of an organism and the corresponding characteristics, arranged in a particular pattern
• Meiosis


  Another type of cell division that generates sex cells (gametes)
• Chromosomes

  Darkly stained bodies within the nucleus consisting of highly coiled and condensed strands of DNA
• Cell Cycle

  1. Interphase (𝐺1, S, 𝐺2)

  2. Mitosis

  3. Cytokinesis
• Interphase


  • Period of growth with DNA replication
• Mitosis


  • Period of reproduction or the actual division of the nucleus

  
• Cytokinesis

  • Division of the cytoplasm and the plasma membrane
• Gap 1 phase (𝐺1)


  • Newly produced daughter cells increase in size, and they prepare themselves for DNA replication
• Synthesis phase (S)


  • Cells DNA is synthesized and replicated, so that the exact copy of the DNA can be distributed to two daughter cells during cell division

  
• Gap 2 phase (𝐺2)


  • Cells continue to grow and synthesize RNA and proteins, cell is checked if it is already prepared for mitosis

  
• Prophase


  1. Nuclear membrane starts to disappear and the nucleolus gradually disintegrates

  2. Spindle fibers are formed between the centrioles and asters on each side of the nucleus

  3. Chromosomes move near the surface of the nuclear membrane, which signals the final disintegration of the nuclear membrane

  4. Spindle fibers from the centrioles connect to the kinetochores of the chromosomes
• Metaphase


  • All chromosomes are aligned at the center (or equator) of the cell
  • The centromeres of each chromosome are completely attached to the spindle fibers
• Anaphase


  1. The centromere splits, and repulsion of the two sister chromatids occurs

  2. Chromosomes now move toward opposite poles

  
• Telophase


  Chromosomes have reached opposite poles and start to elongate, extend, and lengthen until a threadlike appearance is achieved