anaphy

• Digestive system


  System responsible for ingestion, digestion, and elimination of food
• Functions of the digestive system

  • Ingestion
  • Mastication
  • Mixing and propulsion
  • Secretion
  • Hormone release - Ghrelin and leptin
  • Chemical digestion
  • Absorption
  • Elimination

  
• Layers of the GI tract

  • Mucosa (epithelium, lamina propria, muscularis mucosae)
  • Submucosa
  • Muscularis
  • Serosa
• Organs of the digestive system

  • Mouth/oral or buccal cavity (salivary glands, cheeks, lips, tongue, palate, teeth)
  • Pharynx (throat)
  • Esophagus
  • Stomach
  • Small intestines (duodenum, jejunum, ileum)
  • Large intestines/colon (cecum, ascending colon, transverse colon, descending colon, sigmoid colon)

  
• Deglutition (swallowing)


  1. Voluntary stage

  2. Pharyngeal stage (involuntary)

  3. Esophageal stage (involuntary)
• Chyme


  Semiliquid state of food after being converted by hydrochloric acid and other gastric juices in the stomach
• Structure of the small intestine

  • Lined with villi and microvilli to increase surface area
  • Secretion of digestive enzymes to split molecules
  • Absorption of monosaccharides, amino acids, and glycerol

  
• Movement of the large intestine

  • Mass movement two or three times each day
  • Defecation/egestion reflex stimulates defecation
• Feces


  Consists largely of water, undigested food, electrolytes, mucus and bacteria
• Types of salivary glands

  • Parotid glands
  • Submandibular gland
  • Sublingual gland

  
• Salivary secretions


  • Serous secretion (clear solution containing salivary amylase)
  • Mucous secretion (thick, viscous secretion containing mucus)

  
• Gastric glands


  • Secrete gastric juices (HCl, mucus, pepsinogen, small amount of lipase)
  • Secrete intrinsic factor for vitamin B12 absorption
• Intestinal glands


  • Duodenal glands (secrete secretin and cholecystokinin)
  • Brunner's gland (secretes sodium bicarbonate to buffer acidity)
• Brush borders


  • Contain enzymes: enterokinase, disaccharidase, aminopeptidase
• Bile


  Yellow-brownish or olive-green liquid secreted by the liver, with components including bilirubin, bile salts, water, cholesterol, and phospholipids
• Pancreas


  • Contains exocrine cells that secrete pancreatic juices and endocrine cells that form the islets of Langerhans and secrete insulin and glucagon
• Types of pancreatic digestive enzymes

  • Pancreatic lipase (acts on fats)
  • Pancreatic amylase (acts on disaccharides)
  • Pancreatic proteolytic enzymes (trypsinogen, chymotrypsin, procarbopeptidase - break down proteins to amino acids)
• Respiratory System


  Distributes air, exchanges gases, filters/warms/humidifies air, influences speech, allows for sense of smell
• Divisions of the Respiratory System


  • Upper respiratory tract (outside thorax)
  • Lower respiratory tract (within thorax)

  
• Structures of the Upper Respiratory Tract


  • Nose
  • Nasal Cavity
  • Sinuses
  • Pharynx

  
• Nose


  Warms and moistens air
• Septum


  • Separates right and left nostrils
  • Rich blood supply = nose bleeds
  • Epistaxis = nosebleed
• Pharynx


  • 5 openings into the pharynx
• Structures of the Lower Respiratory Tract


  • Larynx
  • Trachea
  • Bronchi
  • Lungs

  
• Larynx


  Voice box, made of cartilage, 2 pairs of folds (vestibular and true vocal cords)

  
• Larynx


  • Thyroid cartilage - Adam's apple - larger in males due to testosterone
  • Epiglottis - flap of skin (hatch) on trachea, moves when swallowing and speaking, closes off trachea when swallowing food
• Trachea


  • Windpipe, consists of smooth cartilage and C shaped rings of cartilage
  • Tracheostomy - cutting of an opening in trachea to allow breathing
• Lungs


  • Extend from diaphragm to clavicles
  • Divided into lobes by fissures
  • Visceral pleura adheres to the lungs
  • Pleurisy = inflammation of the pleural lining

  
• Pulmonary Ventilation


  1. Breathing

  2. Movement of gases through a pressure gradient - high to low

  3. Inspiration - when atmospheric pressure (760 mmHg) is greater than lung pressure, air flows in

  4. Expiration - when lung pressure is greater than atmospheric pressure, air flows out

  5. Pressure gradients are established by changes in thoracic cavity

  
• Respiratory Physiology

  • External respiration - inhaling oxygen into the lungs, and exhaling carbon dioxide
  • Internal respiration - metabolic process by which living cells use blood flowing through the capillaries, absorbing the oxygen they need and releasing the carbon dioxide they create
• Inspiration


  Contraction of diaphragm and intercostal muscles
• Expiration


  Relaxation of diaphragm and intercostal muscles
• Volumes of Air Exchange


  • Tidal volume
  • Expiratory Reserve volume
  • Inspiratory Reserve volume
  • Residual volume
• Vital capacity


  The largest volume of air an individual can move in and out of the lungs, sum of IRV+TV+ERV, depends on size of thoracic cavity, posture, volume of blood in lungs
• Modified Respiratory Movements


  • Sighing
  • Yawning
  • Sobbing
  • Laughing
  • Hiccupping
  • Sneezing
  • Valsalva maneuver
  • Pressurizing the middle ear
• Eupnea is normal quiet breathing, 12-17 breaths per minute
• Hyperpnea is an increase in breathing to meet an increased demand by body for oxygen
• Hyperventilation is an increase in pulmonary ventilation in excess of the need for oxygen, e.g. someone hysterical or from exertion
• Hypoventilation is a decrease in pulmonary ventilation