Sci bitch

• Digestive system is a complex system responsible for breaking down food into nutrients that the body can absorbed and utilize for energy, growth, and repair.
• It involves several organs working together to achieve this process; ALIMENTARY GLAND-_ mouth, pharynx or throat, esophagus, stomach, small intestine, large intestine, rectum and lastly anus.
• ACCESSORY GLAND; salivary gland, liver, gallbladder, and pancreas
• Alimentary gland is a long mascular tube, extends from the mouth to the anus.
• It is a primary pathway through which the food passes during the digestion process
• Alimentary canal involves several organs, each with specific functions in the digestion and absorption.
• Mouth- is the "entry point" of alimentary

  • Mouth receives food where it is mechanically break down by chewing (mastication) and mix food with saliva.
  • saliva contains enzymes (such as amylase) that begin the chemical digestion for breaking down the carbohydrates.
• Pharynx or throat- is a muscular tube located behind the mouth

  • it serves as passageway for foods, liquids and air.
  • During swallowing, the pharynx directs food into the esophagus and prevents it from entering the trachea(windpipe)
• Esophagus- is a muscular tube, that connects the PHARYNX (THROAT) to the stomach.

  • it transports swallowed foods(bolus) from the mouth to the stomach by using rhythmic muscular constractions called peristalsis.
  • the esophageal sphincters AT THE BOTH ENDS OF ESOPHAGUS prevents the backflow of stomach contents(acid) into the esophagus and vice versa.
• Stomach- is a J- shaped organ located below the diaphragm in the upper abdomen.

  • it serves as an storage organ for foods and secretes gastric juices.
  • Gastric juices contains hydrochloric acid and digestive enzymes( such as pepsin) that break down proteins.
  • The stomach's muscular contractions, churn and mix food with saliva, forming a semi-liquid mixture called chyme.
• Small intestine- is a long, coiled tube that extends from the large intestine to the stomach.

  • it is the primary site of digestion and nutrient absorption.
  • The small intestine is divided into (3) segments: duodenum, jejunum, and ileum.
  • the digestive enzymes from the pancreas and bile from the lives aids in breaking down the carbohydrates, proteins and fats.
  • The inner surface of the small intestine is lined with finger-like projections called 'villi' and 'microvilli' which increase the surface area for nutrient absorption into the bloodstream.
• Large intestine- a wider tube that follows the small intestine and forms the final oart of the alimentary gland.

  • it absorbs water and electrolytes, from undigested food materials, forming solid feces.
• Rectum- is the final portion of the large intestine, which feces or poop  are stored until they are expelled from the body.
• Anus- the opening tract at the end of the digestive tract, which feces or poop and eliminated during defecation.
• Accessory gland- plays crucial role in the digestive system by secreting various subtances that aid in the digestion and absorption of nutrients
• Liver- is the largest internal organ located in the upper right abdomen.

  • produces bile, a digestive fluid breaks down fats into smaller droplets to help with digestion and absorption.
  • Bile is stored and concentrated in the gallbladder before being released into the small intestine.
• Gallbladder- located beneath or below the liver.

  Stores and concentrates bile produced by the liver.

  • releases bile into the small intestine(duodenum) when there are fatty foods. Bile aids in the digestion and absorption of fats.
• The stages of digestion; INGESTION, DIGESTION, ABSORPTION, ELIMINATION OR DEFECATION
• What are the two types of digestion? Mechanical and chemical
• Ingestion- the process of taking foods into the mouth.

  • food is initially broken down into smaller pieces through chewing and mix with saliva, to form a bolus which can be easily swallowed.
• Digestion- is the process of breaking down the food into smaller molecules that can be absorbed by the body.
• Digestion, occurs in both mechanical and chemical processes
• Mechanical digestion- is the physical breaking down of foods into smaller particles. Primarily in mouth(chewing) and stomach(chumming)

  Chemical digestion- is the action of enzymes that break down complex molecules into simpler ones. Mainly occurs in the mouth(salivary glands), stomach(gastric juices) and small intestine.
• Absorption- is the process where nutrients and other molecules are absorbed from the digestive system into the bloodstream or lymphatic system.

  • it primarily occurs in the small intestine, where the inner surface is lined with specialized structures called villi and microvilli which increase the surface area for nutrients absorption.
  • Nutrients such as CARBOHYDRATES, PROTEINS, FATS, VITAMINS, AND MINERALS are absorbed into the bloodstream and transported to cells for energy, growth and repair.
• Elimination- is the process of removing indigestible materials (such as fiber and waste products) from the body as feces.
• Digestive enzymes are like tiny helpers in our bodies that helps with important jobs. They are special proteins that speed up chemical reactions.
• Types of enzymes; amylase, maltase, lactase, sucrase, pepsin, trypsin and lipase.
• Amylase- breaks down complex carbohydrates( sugar found in breads and potatoes) into simple SUGARS(monosaccharides)

  • found in small intestine
• Maltase- break down maltose(sugar found in grains) into smaller sugars.

  • found in the small intestine
• Lactase-breaks down lactose (sugar found in milk) into simples sugars.

  • found in the small intestine
• Sucrase- breaks down sucrose(sugar found in the table sugar) into simpler sugars.

  • found in the small intestine.
• Pepsin- helps break down proteins in the stomach into smaller peptides and amino acids.

  • found in the stomach
• Trypsin- continuous breaking proteins into smaller peptides and amino acids in the small intestine. - produced by the pancreas, then released by the small
• Lactase- break down fats (lipids) into fatty acids and glycerol in the small intestine.

  • produced by the pancreas, and works in the small intestine.
• Cell cycle- is a cell ordered or series of cell growth. When the parent cell undergoes cell cycle and eventually cell division, it produces two new daughter cells.
• Two important stages of cell cycle:

  1. Mitosis/cell division
  2. Interphase
• Interphase- is the longest phase of cell cycle.

  • during interphase, the cell grows, carries out it's normal functions and duplicates it's DNA and duplicate chromosomes IN PREPARATION FOR CELL DIVISION. SYNTHESIS ORGANELLE OCCURS
• Interphase is DIVIDED INTO THREE (3) SUB PHASE;

  1. FIRST PHASE OR (G1) PHASE: the cell grows(INCREASE IN SIZE) IN PREPARATION FOR RHE CELL DIVISION and carries out it's normal functions.

  • CHECKPOINT: CELL GROWTH CHECKPOINT- Check the size of the cell and has made the proper proteins for the synthesis phase. If not, the cell goes through the (G0) OR RESTING PHASE until it is ready to divide.
• 2. SECOND PHASE or S (SYNTHESIS) PHASE- DNA replication occurs, resulting a complete genetic information AND CHROMOSOMES ARE DUPLICATED.

  • CHECKPOINT: DNA SYNTHESIS CHECKPOINT- Check if DNA have been replicated correctly. If yes, the cell continues to MITOSIS.
• THIRD PHASE OR (G2) PHASE- THE CELL CONTINUES TO GROW IN PREPARATION FOR CELL DIVISION BY SYNTHESIZING PROTEINS AND ORGANELLES.

  (G0) PHASE- THE TEMPORARY AND PERMANENT RESTING PHASE OF CELL. CELLS IN (G0) ARE IN NONDIVIDING PHASE (not growing/DIVIDING)

  • permanent rest of cells- the damage in the neurons/nerve cells ARE NO LONGER capable of being replace/repaired.
  • temporary rest of cells- Red Blood Cells- READY TO DIVIDE and exit (G0) PHASE and proceed to next