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bet 1/12 Sana 26.02.2022 Hajmi 13,42 Mb. #472319
Bog'liq
2 5355150900383974823
Ventral Body Cavities Thoracic cavity subdivisions: Two pleural cavities Mediastinum Contains pericardial cavity Surrounds thoracic organs Pericardial cavity Ventral Body Cavities Abdominopelvic cavity subdivisions: Abdominal cavity Contains stomach, intestines, spleen, and liver Pelvic cavity Cranial cavity (contains brain) Vertebral cavity (contains spinal cord) Pericardial cavity within the mediastinum Ventral body cavity (thoracic and abdominopelvic cavities) Abdominal cavity (contains digestive viscera) Pelvic cavity (contains urinary bladder, reproductive organs, and rectum) Thoracic cavity (contains heart and lungs) Serous Membrane (Serosa) Thin, double-layered membrane separated by serous fluid Parietal serosa lines internal body walls Visceral serosa covers the internal organs Right upper quadrant (RUQ) Right lower quadrant (RLQ) Left upper quadrant (LUQ) Left lower quadrant (LLQ) Other Body Cavities Oral and digestive cavities Nasal cavity Orbital cavities Middle ear cavities Synovial cavities Body Quadrants Right Upper Quadrant (RUQ) Left Upper Quadrant (LUQ) Right Lower Quadrant (RLQ) Left Lower Quadrant (LLQ) 1. Common about DT 1. Common about DT The GI tract (gastrointestinal tract) The muscular alimentary canal Mouth Pharynx Esophagus Stomach Small intestine Large intestine Anus The accessory digestive organs Supply secretions contributing to the breakdown of food Teeth & tongue Salivary glands Gallbladder Liver Pancreas The Digestive Process Ingestion Taking in food through the mouth Propulsion (movement of food) Swallowing Peristalsis – propulsion by alternate contraction &relaxation Mechanical digestion Chewing Churning in stomach Mixing by segmentation Chemical digestion By secreted enzymes: see later Absorption Transport of digested end products into blood and lymph in wall of canal Defecation Chemical digestion Chemical digestion Complex food molecules (carbohydrates, proteins and lipids) broken down into chemical building blocks (simple sugars, amino acids, and fatty acids and glycerol) Carried out by enzymes secreted by digestive glands into lumen of the alimentary canal Histology of alimentary canal wall Same four layers from esophagus to anal canal Mucosa Submucosa Muscularis externa Serosa from lumen (inside) out Inner layer: the mucosa* (mucous membrane) Three sub-layers Lining epithelium Lamina propria Muscularis mucosae Epithelium: absorbs nutrients, secretes mucus Continuous with ducts and secretory cells of intrinsic digestive glands (those within the wall) Extrinsic (accessory) glands: the larger ones such as liver and pancreas Lamina propria (собстенная пластинка) Loose connective tissue with nourishing and absorbing capillaries Contains most of mucosa-associated lymphoid tissue (MALT) Muscularis mucosae Thin layer of muscle producing only local movements Second layer: the submucosa* Connective tissue containing major blood and lymphatic vessels and nerves Many elastic fibers so gut can regain shape after food passes Next in, the muscularis externa* Two layers of smooth muscle responsible for peristalsis and segmentation Inner circular layer (circumferential) Squeezes In some places forms sphincters (act as valves) Outer longitudinal layer: shortens gut Last (outer), the serosa* (the visceral peritoneum) Simple squamous epithelium (mesothelium) Thin layer of areolar connective tissue underneath Exceptions: Parts not in peritoneal cavity have adventitia, lack serosa Some have both, e.g. retroperitoneal organs Smooth muscle Muscles are spindle-shaped cells One central nucleus Grouped into sheets: often running perpendicular to each other Peristalsis No striations (no sarcomeres) Contractions are slow , sustained and resistant to fatigue Does not always require a nervous signal: can be stimulated by stretching or hormones 6 major locations: inside the eye 2. walls of vessels 3. respiratory tubes 4. digestive tubes 5. urinary organs 6. reproductive organs Nerves Enteric nervous system: the gut’s own Visceral plexuses within gut wall controlling the muscles, glands and having sensory info Myenteric: in muscularis Submucosal 100 million neurons! (as many as the spinal cord) Autonomic input: speeds or slows the system Parasympathetic Sympathetic Largely automatic 2. Peritoneum (Брюшина) Peritoneum: serous membranes of the abdominopelvic (брюшиннотазной) cavity Visceral peritoneum: covers external surfaces of most digestive organs Parietal peritoneum: lines body wall Peritoneal cavity: slit-like potential space between visceral and parietal peritoneum Serous fluid – lubricating (смазка) Do'stlaringiz bilan baham:
