Metabolism Lecture
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Metabolism Lecture



3H ateneo de davao nursing metabolism lecture

3H ateneo de davao nursing metabolism lecture



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Metabolism Lecture Metabolism Lecture Presentation Transcript

  • Anatomy and Physiology
  • The mouth, buccal cavity, or oral cavity is the first portion of the alimentary canal that receives food and begins digestion by mechanically breaking up the solid food particles into smaller pieces and mixing them with saliva.
    Lined with epithelial cells and mucuous membrane
    Lip muscle: orbicularisoris
  • Enamel is the hardest and most highly mineralized substance of the body, the outer layer of tooth
    Dentin is the substance between enamel or cementum and the pulp chamber that acts as a protective layer and supports the crown of the tooth
    Cementum is a specialized bony substance covering the root of a tooth. Its principal role of cementum is to serve as a medium by which the periodontal ligaments can attach to the tooth for stability
    The dental pulp is the central part of the tooth filled with soft connective tissue. This tissue contains blood vessels and nerves that enter the tooth from a hole at the apex of the root
  • Digestion is the mechanical and chemical breaking down of food into smaller components, to a form that can be absorbed
  • Chewing
    Or mastication, is the mechanical process of breaking down food into smaller particles
  • Saliva
    Is secreted by the sublingual and submandibular and parotid glands
    Function: is to lubricate and soften food mass
    Contains the enzyme ptyalin (amylase) which breaks down starches to maltose
    Chewed food is then called bolus
  • Swallowing
    Or deglutition, is the act of passing down food/ bolus from the mouth down to the esophagus
  • Esophagus
    A hollow, muscular tube the lies posterior to the trachea and larynx
    Serves as the passage of food from the mouth to the stomach
    The Lower esophageal sphincter , a zone of increased pressure that provides a physiologic barrier to protect the esophageal mucosa from the effects of gastric reflux
  • Peristalsis
    Are involuntary waves of the glosopharyngeal nerves stimulated by the act of swallowing
    Secondary stimulation of peristalsis occurs with dilatation of the lower half of the esophaus
  • The Stomach
    Has 3 anatomic divisions:
    The fundus, lies above and to the left of the cardiac sphincter
    The body
    The antrum or pylorus
  • Sphincters
    Regulate inflow and outflow from the stomach.
    The cardiac sphincter at the proximal end of the stomach allows inflow of food and prevents backflow of material
    The pyloric sphincter lies between the distal end of the stomach and the duodenum permits the flow of chyme from the stomach
  • Stomach
    Has four layers
    Serous- the visceral peritoneum
    Muscular- produces peristaltic movements
    Submucous- contains blood, lymph and nerve plexuses
    Mucous-epithelial cells with microscopic glands
  • Chief cells- secrete mucus and pepsinogen
    Parietal cells- secrete hydrochloric acid, stimulated by gastrin. Also secrete the intrinsic factor
    Neck cells- secrete mucus
    Pyloric glands- secrete gastrin
  • Stomach
    Mixing and liquefication of bolus into chyme
    Blood supply: celiac artery
    Drainage: portal vein
  • Innervation:
    • Vagus nerve- parasympathetic stimulation
    • Results in increased secretion of gastrin and pepsin and increased gastric motor activity
    • The greater splanchic nerve and celiac ganglia- sympathetic innervation
    • Inhibits gastric secretion and motility
  • Gastric secretion
    The stomach secretes 1500-3000 mL of gastric juice per day
    Its components include:
    Hydrochloric acid
    Secretion is stimulated by vagal activity, acetylcholine, histamine and gastrin
  • Phases of gastric secretion
    Cephalic phase
    Stimulated by hunger, food odor, sight and smell
    Results secretion of acid pepsin and mucus
    Lasts for 30-4- minutes after eating
    Occurs when the bolus of food reaches the antrum
    Gastrin stimulates parietal cells of the antrum to secrete hydrochloric acid
    Continues until the acidity of the gastric contents reaches 1.5 or less
    Stimulated by food entering the duodenum
    Duodenal pH gradually decreases resulting in the release of secretin that inhibits gastric secretion and slows gastric emptying
  • Gastric inhibition
    Secretions are decreased by:
    Vagal stimulation
    Enterogastrones- secretin and cholecystokinin
    Alterations in blood flow
  • Small Intestine
    22 feet long, 1 inch in diameter
    Divided into 3 segments
    duodenum- 9.8 inches
    Jejunum- middle section,2.5 m
    Ileum- joins the colon through the ileoceccal valve,3.5
    where most chemical digestion takes place.
    Most of the digestive enzymes that act in the small intestine are secreted by the pancreas
    The enzymes enter the small intestine in response to the hormone cholecystokinin, which is produced in the small intestine in response to the presence of nutrients.
    The hormone secretin also causes bicarbonate to be released into the small intestine from the pancreas in order to neutralize acid coming from the stomach.
  • Proteins and peptides are degraded into amino acids.
    Chemical breakdown begins in the stomach and continues in the small intestine.
    Proteolytic enzymes, including trypsin and chymotrypsin, are secreted by the pancreas and cleave proteins into smaller peptides.
  • Lipids (fats) are degraded into fatty acids and glycerol.
    Pancreatic lipase breaks down triglycerides into free fatty acids and monoglycerides. Pancreatic lipase works with the help of the salts from the bile secreted by the liver and the gall bladder
  • Carbohydrates are degraded into simple sugars, or monosaccharides
    Pancreatic amylase breaks down carbohydrates into oligosaccharides.
    the digested food can now pass into the blood vessels in the wall of the intestine through the process known as diffusion.
    The small intestine is the site where most of the nutrients from ingested food are absorbed.
  • The inner wall, or mucosa, of the small intestine is lined with simple columnar epithelial tissue.
    Structurally, the mucosa is covered in wrinkles or folds called plicaecirculares where microscopic finger-like pieces of tissue called villi project. The individual epithelial cells also have finger-like projections known as microvilli.
    The function of the plicaecirculares, the villi and the microvilli is to increase the amount of surface area available for the absorption of nutrients.
    simply absorbs vitamins that are created by the bacteria inhabiting the colon. It also absorbs water and compacts feces
    stores fecal matter in the rectum until eliminated through the anus and thus is responsible for passing along solid waste
  • houses over 700 species of bacteria that perform a variety of functions.
    These bacteria also produce large amounts of vitamins, especially vitamin K and Biotin for absorption into the blood.
    acts as a temporary storage facility for feces. As the rectal walls expand due to the materials filling it from within, stretch receptors from the nervous system located in the rectal walls stimulate the desire to defecate
  • ANUS
    the external opening of the rectum
    closure is controlled by sphincter muscle
  • intra-rectal pressure builds as the rectum fills with feces, pushing the feces against the walls of the anal canal. Contractions of abdominal and pelvic floor muscles can create intra-abdominal pressure which further increases intra-rectal pressure.
    The internal anal sphincter responds to the pressure by relaxing, thus allowing the feces to enter the canal. The rectum shortens as feces are pushed into the anal canal and peristaltic waves push the feces out of the rectum.
    Relaxation of the internal and external anal sphincters allows the feces to exit from the anus, finally, as the levatorani muscles pull the anus up over the exiting feces
    largest glandular organ with a weight of about 1.5 kg
    It is reddish brown organ with four lobes of unequal size and shape
    location: the right side of the abdominal cavity just below the diaphragm and is connected to two large blood vessels, the hepatic artery and the portal vein.
    Functional units: hepatocytes
  • Liver functions
    Protein/ amino acid synthesis
    Lipid metabolism
    Production of coagulation factors
    Production and secretion of bile
    major site of thrombopoietin production
  • The breakdown of insulin and other hormones
    The liver breaks down hemoglobin, creating metabolites that are added to bile as pigment
    The liver breaks down or modifies toxic substances and most medicinal products in a process called drug metabolism.
    The liver converts ammonia to urea.
  • The liver stores a multitude of substances, including glucose ,vitamin A,vitamin D, B12, iron and copper.
    The liver produces albumin,
    The liver synthesizes angiotensinogen
    both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as an exocrine gland secreting pancreatic juice containing digestive enzymes that pass to the small intestine
  • Made of two types of tissue:
    islets of Langerhans – endocrine function, hormone production and secretion
    Alpha cells-secrete glucagon
    Beta cells- secrete insulin
    Delta cells-secrete somatostatin
  • b. Acinar cells-digestive enzyme production
    pancreatic lipase
    pancreatic amylase
    located near the junction of the small intestine and the large intestine or the cecum
    10 cm in length, but can range from 2 to 20 cm
    Thought to be a vestigial structure
    A pouch that stores bile temporarily
    stores about 50 mL of bile, which is released when food containing fat enters the digestive tract, stimulating the secretion of cholecystokinin
    bile, produced in the liver, emulsifies fats in partly digested food.
  • Bile
    bitter yellowish, blue and green fluid secreted by hepatocytes from the liver
    The main components include:
    Bile pigments
    Bile acids
    Phospholipids mainly lecithin
    Bicarbonate and other ions
  • Bile then flows into the common hepatic duct, which joins with the cystic duct from the gallbladder to form the common bile duct. The common bile duct in turn joins with the pancreatic duct to empty into the duodenum.
    If the sphincter of Oddi is closed, bile is prevented from draining into the intestine and instead flows into the gallbladder, where it is stored
  • Functions:
    Emulsification of fat
    absorption of the fat-soluble vitamins D, E, K and A
    route of excretion for the hemoglobin breakdown product
  • Assessment of the Gastrointestinal System
  • Diagnostic Evaluation
  • Barium sulfate
    a chalky, radiopaque substance that allows fluoroscopy and x-ray examination of the GI system
    Stools may be light colored within 24-72 hours after intake.
    It may cause constipation
  • Upper GI series/Barium Swallow
    Permits the visualization of the esophagus, stomach duodenum and proximal jejunum
    Preparation: low residue diet , withhold anticholinergic drugs, NPO post midnight
    After swallowing barium, the patient assumes various positions on the x-ray table
  • Lower GI series/Barium Enema
    Used to diagnose disorders of the colon
    Preparation: low residue diet, NPO post midnight, laxative pre-procedure until the return flow is clear
    Tell the person may feel the urge to defecate
  • Endoscopy
    Is the direct visualization of the GI system by means of a lighted flexible tube.
  • Upper GI endoscopy
    Includes esophagoscopy, gastroscopygastroduodenescopy
    NPO at least 6 hours
    Atropine sulfate may be given
    Sedatives and tranquilizers
    Dentures should be removed
    Local anesthetics may be given
  • Post-procedure
    Do not give food or water until gag reflex returns
    Anesthetic sprays or normal saline gargles may be given
  • Lower GI Endoscopy
    Is the visualization of the bowel through a proctoscope, sigmoidoscope or colonoscope
  • Fecal Analysis
    Stools are examined for chemical constituents, bacteria, parasites, lipids and occult blood
    Normal pH is between 6.8- 7.3
    Contents include clcium, phosphates, carbohydrates, fat, nitrogen, protein, amylase, lipase, and trypsin
    It is brown and formed
  • Reasons for placing intestinal tubes:
    Decompression of the GI tract (i.e. intestinal obstruction)
    Lavage (washing out the stomach)
    Gavage (feeding)
    Compression (control bleeding)
    Diagnosis (analysis of GI contents)
  • Levin (standard nasogastric tube)
  • Salem Sump (nasogastric tube with side ports)
  • Dobhoff/PEG (enteral feeding)
  • Sengstaken-Blakemore (compression of gastric cardia and distal esophagus to control variceal bleeding)
  • Long tubes (Miller-Abbott/Cantor)
  • Insertion Procedure for NG tube:
    Sit patient upright (preferable)
    Inspect nares, pick larger of the nares
    Lubricate NG tube Insert tube into back of nose with gentle pressure
    Ask patient to swallow, advance tube rapidly but gently (patient may sip water)
    Confirm placement of tube in stomach
  • Dental Disorders
    1. dental plaque- a soft mass of proliferating bacteria with a scattering of leukocytes, macrophages in a polysaccharide-protein matrix that adheres to the teeth.
    It is usually undetectable unless it absorbs pigment within the cavity
    Prevention: tooth care
  • Dental Caries
    Or tooth decay, may be caused by resistance of the tooth enamel, plaque and bacteria
    Acid produced by bacteria in the teeth decalcify enamel when pH goes below 5.6
    Treatment: removal of decayed teeth, restoration
  • Fillings
    Crowns-The decayed or weakened area is removed and repaired. A crown is fitted over the remainder of the tooth. Crowns are often made of gold, porcelain, or porcelain attached to metal.
    Root canals-The center of the tooth, including the nerve and blood vessel tissue (pulp), is removed along with decayed portions of the tooth. The roots are filled with a sealing material. The tooth is filled, and a crown may be placed over the tooth if needed.
  • Gingivitis and Periodontitis
    Inflammation of the gums/gingiva
    Presents with bleeding, alteration in the color , swelling and ulceration
    Inflammation extending to the alveolar bone and ligament
    There is bleeding, swelling and breath odor
  • treatment
    Reduce inflammation,
    Tooth cleaning
    Antibacterial mouthwash
    Emphasize oral hygiene
  • Stomatitis
    inflammation of the mouth.
    May be caused by a chemical or mechanical trauma, chemotherapy
    Management: Removal of cause, soft bland diet, topical medication, oral hygiene
  • Aphthous Stomatitis
    Or canker sores, are ulcers that form in the soft tissues of the mouth
    May be caused by emotional stress, trauma, vitamin deficiency, drug allergy or endocrine imbalance
    Management: topical steroids, oral hygiene
  • Actinic cheilitis
    also known as solar cheilitis, sailor's lip, or farmer's lip, is a form of cheilitis which is the counterpart of actinic keratosis of the skin and can develop into squamous cell carcinoma.
    there is thickening whitish discoloration of the lip at the border of the lip and skin. There is also a loss of the usually sharp border between the red of the lip and the normal skin, known as the vermillion border.
    The lip may become scaly and indurated the lesion is usually painless, persistent,
  • treatment
    • Chemotherapy
    • electrosurgery
  • Leukoplakia
    adherent white plaques or patches on the mucous membranes of the oral cavity, including the tongue. The clinical appearance is highly variable.
    Leukoplakia is not a specific disease entity, but is diagnosis of exclusion. It must be distinguished from diseases that may cause similar white lesions, such as candidiasis
    It is a precancerous sorethat develops on the tongue or the inside of the cheek in response to chronic irritation
  • symptoms
    Usually on the tongue
    May be on the inside of the cheeks
    In females, occasionally on the genitals
    Usually white or gray
    May be red (called erythroplakia, a condition that can lead to cancer)
    Slightly raised
    Hardened surface
  • Treatment
    Goal of treatment is to get rid of the lesion.
    Removing the source of irritation is important and may cause the lesion to disappear.
    Treat dental causes such as rough teeth, irregular denture surface, or fillings as soon as possible.
    Stop smoking or using other tobacco products.
    Do not drink alcohol.
    Surgery to remove the lesion
  • Hiatal Hernia
    Is the protrusion of the stomach upward into the mediastinal cavity through the esophageal hiatus of the diaphragm
    Commonly caused by trauma or weakness due to loss of muscle tone which results to regurgitation and motor dysfunction
  • Symptoms
    Dull, heavy bloating pain
  • Diagnosis
    Barium swallow
    Motility studies
  • Management
    Prevent symptoms by keeping acidic acidic pepsin and alkaline biliary secretions from contacting the esophagus
    1.Avoid bending, lifting, coughing, vomiting or straining
    2. Eat food with more fiber
    3. Stop/decrease smoking
    4.Wear non-constrictive clothing
  • 5. Eat small but frequent meals
    6.Avoid highly seasoned food
    7. Eat in a sitting position
    8. Avoid reclining or lying down after a meal
  • Surgical Management
    Aim:to restore the hernia below the diaphragm, narrow the esophageal hiatus, and stop reflux
    Procedure: Nissenfundoplication, Hill operation, Belsey.
    Postoperatively: assess for dysphagia, early satiety, epigastric fullness, leakage into tube due to improper placement
  • Gastritis
    Or gastric inflammation often occurs with nausea, vomiting, discomfort, malaise, anorexia
    May be caused by ingestion of corrosive, erosive or infectious substance, alcohol,
    Usually of short duration
    Diagnosis: history, gastroscopic examination
    Symptomatic treatment
    Electrolyte replacement if severe
  • Achalasia
    esophageal motility disorder wherein the smooth muscle layer of the esophagus loses normal peristalsis and the lower esophageal sphincter (LES) fails to relax properly in response to swallowing
    Causes include:
    Damage to the nerves of the esophagus
    Infection with a parasite
    Inherited factors
  • Symptoms
    difficulty swallowing,
    regurgitation and sometimes chest pain
    weight loss,
    coughing when lying in a horizontal position,
    chest pain which may be perceived as heartburn
  • diagnosis
    Barium swallow
    Esophageal manometry
  • Treatment/management
    Eating small, frequent feedings
    Nifedipine-decreases LES pressure
    Lifestyle changes: raising the head of the bed, avoiding spicy food, caffeinated beverages
    Botulinum toxin –paralyzes the LES
    Pneumatic dilation-muscle fibers are stretched and slightly torn by forceful inflation of a balloon placed inside the lower esophageal sphincter.
    Surgery-Heller myotomy, lengthwise cut along the esophagus, starting above the LES and extending down onto the stomach a little way, partial fundoplication or "wrap" is generally added in order to prevent excessive reflux,
  • diverticulosis
    Refers to the presence of noninflammed pouches in the gastrointestinal tract
  • Diverticulitis
    Inflammation of a diverticulum. It is a blind outpouching of intestinal mucosa through the muscular coat.
    It is common to both men and women, in ages 45 years and above and obese
    When fecaliths enter the divercula, and do not liquefy they may become trapped and cause irritation and inflammation
  • Symptoms
    Episodic, dull, left quadrant, mid-abdominal pain
    Changes in bowel habits
    Increased flatus
    Low grade fever
    Rectal bleeding
  • Management
    Colonic rest
    Avoid activities that increase intra abdominal pressure
    Increase oral fluid intake
    Reduction of weight
  • Appendicitis
    Inflammation of the appendix
    May be caused by fecaliths, kinking of the appendix, swelling of the bowel wall,
    Commonly occurs in both sexes and in adolescents and young adults
  • Symptoms
    Begins with abdominal discomfort which comes in waves that start in the epigastrium or periumbilical region then shifts to right lower quadrant when the inflammatory process spreads to serosal layers of the bowel
    Pain then becomes steady at mcburney’s point, which is midway between the anterior superior iliac crest and umbilicus
    Vomiting, low grade fever, mild leukocytosis
  • Management
    Removal of the appendix within 24-48 hours after onset of symptoms
  • Peptic Ulcers
    Is a break in the continuity of GI mucosa, it may occur in any part of the tract that comes in contact with gastric juices
    Etiology: hypersecretion of gastric juice, loss of mucosal integrity, inability of the regulators to inhibit gastric secretion, emotional stress, medications, hormones and chemical ingestions
    Has two types: Duodenal and Gastric
  • Duodenal Ulcer
    Have higher incidences than gastric ulcers
    Characterized by high gastric cid secretion attributed to a greater mass of parietal cells
    Patients empty their stomach more rapidly
  • etiology
    Helicobacter pylori infection
    Altered gastric acid levels
    Smoking and alcohol
    Aspirin and NSAIDS
    Genetic predisposition
    Stress, chronic anxiety, type A personality
  • Duodenal Ulcer
    Burning, aching, gnawing pain at the right epigastrium
    Pain occurs 2-3 hours after meals
    Causes patient to awaken at night
    Pain relieved by eating
    Epigastric tenderness
  • Gastric Ulcer
    Pain location: upper epigastrium
    Burning, aching, gnawing pain 30 minutes to 1 hour after meals
    Worsened by intake of food
    Epigastric tenderness
  • Diagnosis
  • Complications
    Gastric perforation
  • Stress Ulcers
    Occur after an acute medical crisis
    Curling’s Ulcer- after severe burns
    Cushing’s Ulcer- after a head injury or intrcranial disease
    Zollinger-Ellison syndrome -a disorder where increased levels of the hormone gastrin are produced, causing the stomach to produce excess hydrochloric acid.
  • Management
    Aim: promote stomach rest by neutralizing the hydrochloric acid, inhibiting acid secretion and protect the mucosa
    Pharmacologic mangement:
    Prostaglandin analogs
    Histamine antagonists
    Proton pump inhibitors
  • Surgical Management
    Vagotomy-to eliminate the acid-stimulus to gastric cells
    Antrectomy/ Billroth I & II- to reduce acid secreting portions of the stomach
    Nursing Responsibilities:
    Watch out for complications such s hemorrhage and dumping syndrome
    Check drainage of tubes, do not irrigate unless indicated
  • Inflammatory bowel disease
    Includes both regional enteritis and ulcerative colitis
    Characterized by exacerbations and remissions and are chronic, recurrent
    Common in young adults
    May be trigerred by pesticides, food additives, tobacco, radiation, heredity
    Also called Crohn’s disease, a chronic relapsing disease that develop in any segment of the GI tract.
    Its most common site is the terminal ileum
    Its cause is unknown, but may have genetic basis
    Lesions develop in separated segments of the bowel that are grossly visible and sharply demarcated
    inflammation, of all layers of the bowel wall of the intestinal mucosa
  • Symptoms
    Enlarged lymph nodes
    Apperance of peyer’s patches
    Fistulas and abscess formation
    Abdominal tenderness
    Pain that is colicky
    Diarrhea, flatulence and steatorrhea
    Diagnosis: “string sign” seen on xray after barium enema