Science 8 • 4th Quarter

• Large intestine


  The average length of the large intestine is 1.5 m (5 feet)
• Parts of the large intestine

  • Caecum
  • Colon
  • Rectum
• Caecum


  • First part of the large intestine, about 6 cm in length
• Rectum


  • Last part of the large intestine, about 13 cm in length
• The large intestine absorbs water and eliminates indigestible food residues as feces
• The large intestine is about 1-5 meters long and absorbs nutrients left by the small intestine
• Bacterial digestion and fermentation


  Occurs in the large intestine
• Accessory organs that help in digestion

  • Salivary glands
  • Liver
  • Gall bladder
  • Pancreas
• Salivary glands


  Secrete saliva into the oral cavity
• Pancreas


  A pale gray mixed gland, about 12-15 cm long
• Exocrine functions of the pancreas


  • Produces pancreatic juice containing enzymes to digest fats, carbohydrates and proteins
• Endocrine functions of the pancreas


  • Produces insulin and glucagon to regulate sugar
• Liver


  The largest organ in the body, located on the right side, weighing 1-2.5 kg
• Functions of the liver


  • Produces bile to aid digestion of fats
  • Filters toxins and waste including drugs, alcohol and poisons
• Gall bladder


  A small, thin-walled, pear-shaped structure that stores bile from the liver
• Fatty diets can cause the formation of gallstones in the gall bladder
• Digestive system disorders and their symptoms/prevention

  • Diarrhea (abdominal pain, urgent need to defecate, fever, loose stools, nausea, bloating, vomiting)
  • Constipation (dry, hard, lumpy stool, difficulty passing stool, bloating, flatulence, nausea)
  • Hepatitis (nausea, jaundice - staining of the skin and whites of the eyes yellow)
  • Peptic ulcer (burning, sharp pain in stomach, heartburn, bloating)
  • Hemorrhoids (rectal bleeding, itchy, painful lumps around the anus)
  • Appendicitis (pain around the belly button, loss of appetite, nausea, vomiting)
• Human cells have 46 chromosomes in 23 pairs
• Cell cycle


  The series of events a cell goes through to divide and produce new cells
• Stages of the cell cycle

  • Interphase (G1, S, G2)
  • Cell division phase
• Interphase


  • The period when the cell prepares for division and the chromosomes are long and extended
• Cell division phase


  • The period when the chromosomes become condensed and thickened
• DNA


  The genetic material in the form of a double-stranded molecule
• Chromatids


  The two identical strands of a duplicated chromosome
• G0 phase


  A quiescent stage where cells are unable to divide
• Mitosis


  • A type of cell division that produces two identical daughter cells with the same number of chromosomes
• Stages of mitosis

  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Prophase


  • The nuclear membrane and nucleoli disappear, and the sister chromatids become visible
• Metaphase


  • The chromosome pairs align at the center of the cell, preparing for separation
• Anaphase


  • The sister chromatids separate and move to opposite poles of the cell
• Telophase


  • The nuclear membrane reforms and the chromosomes decondense
• Cytokinesis


  The division of the cytoplasm to form two separate daughter cells after mitosis
• When cell division goes wrong, cells may divide faster and develop into cancerous tumours
• Metaphase


  Pairs allign at the center of the tell Prepare for seperation.
• Anaphase


  Chromosomes and sister chromosomes chromatids at the atorial pline betre The sepertition ct Sister chromatid
• Cytokinesis


  Division of the cytoplasm to form seperate daughter cell immediately after mitosis.
• Meiosis


  Responsible for producing gametes for sexual reproduction.
• Meiosis

  Greek word meiosis means to make smaller.
• Prophase I


  Homologous chromosomes pair up. At this time, exchange of genetic mater acz crossing-over
• Metaphase I


  Each pair of single homologous chromosomes attach to a spindle fiber. One in the gola Anaphase 1 while the other to pal Moves Mitosis chromo come to the opposite poles.