Anatomy & Physiology OF

HARISHANKAR SAHUB.PHARMA FINAL YEARSRIP,KUMHARI

BY-

Digestive System

Organs of the Digestive System Mouth teeth Salivary glands Pharynx Esophagus Stomach Liver Gallbladder (GB) Pancreas Small intestine Large intestine Rectum Anus

Main Functions Digesting food

– Physical and chemical breakdown of large food into molecules: glucose, triglycerides, amino acids

Absorbing nutrients– From intestines– Circulated through the body by cardiovascular system

Eliminating waste– Any food that cannot be digested or absorbed is expelled

Oral Cavity (mouth)• Roof is palate

– Hard – bony anterior – Soft – flexible posterior

• Hanging down from soft palate is uvula– Speech production– Location of gag reflex

Oral Cavity

• Cheeks are lateral walls

• Lips are anterior opening

• Entire cavity lined with mucous membrane

Oral Cavity

• Digestion begins when food enters mouth– Mechanically broken up by chewing

• Tongue moves food within mouth• Mixes with saliva

– Digestive enzymes– Lubricates

• Taste buds on tongue surface– Detect bitter, sweet, salty, sour flavors

Processes of the Mouth

· Mastication (chewing) of food· Mixing masticated food with saliva· Initiation of swallowing by the tongue· Allowing for the sense of taste

Salivary Glands• Produce saliva

– Prevents bacterial infection

– Lubrication– Contains salivary

amylase• Breaks down starch

Three pairs of Salivary Glands

• Parotid – lateral side of face, anterior to ear, drain by parotid duct to vestibule near 2nd upper molar

• Submandibular – medial surface of mandible – drain near lingual frenulum drain posterior to lower molars

• Sublingual – in floor of mouth - drain near frenulum

Function

· Mixture of mucus and serous fluids· Helps to form a food bolus· Contains salivary amylase to begin

starch digestion· Dissolves chemicals so they can be

tasted

Teeth· The role is to masticate (chew) food· Humans have two sets of teeth1. Deciduous (baby or milk) teeth

· 20 teeth are fully formed by age two

2. Permanent teeth· Replace deciduous teeth beginning between the ages

of 6 to 12· A full set is 32 teeth, but some people do not have

wisdom teeth

Classification of Teeth

Pharynx Anatomy

· Nasopharynx – not part of the digestive system

· Oropharynx – posterior to oral cavity

· Laryngopharynx – below the oropharynx and connected to the esophagus

Pharynx Function

· Serves as a passageway for air and food· Food is propelled to the esophagus by two

muscle layers· Longitudinal inner layer· Circular outer layer

· Food movement is by alternating contractions of the muscle layers (peristalsis)

Esophagus· 10 inches long in adults· Food enters from pharynx· Runs from pharynx to stomach

through the diaphragm· Conducts food by peristalsis

(slow rhythmic squeezing)· Passageway for food only

(respiratory system branches off after the pharynx)

Joins stomach at cardiac orifice*Cardiac sphincter at cardiac orifice to prevent regurgitation (food coming back up into esophagus)

Esophagus___________

Stomach • Lies mostly in LUQ

– But pain can be epigastric or lower

• Just inferior to (below) diaphragm

• Anterior (in front of) spleen and pancreas

• Tucked under left lower margin of liver

• Anchored at both ends but mobile in between

• Capacity: 1.5 L food; max capacity 4L (1 gallon)

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epigastrium

junction with esophagus

funnel shaped

contains pyloric sphincter

dome

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Stomach• J-shaped; widest part of alimentary canal• Temporary storage and mixing – 4 hours

– Into “chyme”• Starts food breakdown

– Pepsin (protein-digesting enzyme needing acid environment)

– HCl (hydrochloric acid) helps kill bacteria– Stomach tolerates high acid content but esophagus doesn’t

– why it hurts so much when stomach contents refluxes into esophagus (heartburn; GERD)

• Most nutrients wait until get to small intestine to be absorbed; exceptions are:– Water, electrolytes, some drugs like aspirin and alcohol

(absorbed through stomach)18

Stomach Functions

· Acts as a storage tank for food· Site of food breakdown· Chemical breakdown of protein begins· Delivers chyme (processed food) to the

small intestine· It secretes intrinsic factor which is

necessary for the absorption of vit.B12

Small intestine• Longest part of alimentary canal (2.7-

5 m)• Site of greatest amount of digestion

and absorption• Small intestine has 3

subdivisions– Duodenum – 5% of length– Jejunum – almost 40%– Ileum – almost 60%

• Modifications– Circular folds or plicae circulares,

villi, lacteal, microvilli• Cells of mucosa

– Absorptive, goblet,granular, endocrine

• Small intestine designed for absorption– Huge surface area because of great length– Structural modifications also increase absorptive area

• Circular folds (plicae circulares)• Villi (fingerlike projections) 1 mm high – simple columnar epithelium: velvety• Microvilli

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Absorptivie cell with microvilli to increase surface area & many mitochondria: nutrient uptake is energy-demanding

Villi of the Small Intestine

· Fingerlike structures formed by the mucosa

· Give the small intestine more surface area

Microvilli of the Small Intestine

· Small projections of the plasma membrane

· Found on absorptive cells

Figure 14.7c

Structures Involved in Absorption of Nutrients

· Absorptive cells· Blood

capillaries· Lacteals

(specialized lymphatic capillaries)

Digestion in the Small Intestine

Pancreatic enzymes play the major digestive function· Help complete digestion of starch (pancreatic

amylase)· Carry out about half of all protein digestion

(trypsin, etc.)· Responsible for fat digestion (lipase)· Digest nucleic acids (nucleases)· Alkaline content neutralizes acidic chyme

Absorption in the Small Intestine

· Water is absorbed along the length of the small intestine

· End products of digestion· Most substances are absorbed by active

transport through cell membranes· Lipids are absorbed by diffusion

· Substances are transported to the liver by the hepatic portal vein or lymph

Large Intestine

· Larger in diameter, but shorter than the small intestine

· Frames the internal abdomen

· Digested residue reaches it Main function: to absorb water and electrolytes

Structures of the Large Intestine· Cecum – saclike first part of the large intestine· Appendix

· Accumulation of lymphatic tissue that sometimes becomes inflamed (appendicitis)

· Hangs from the cecum· Colon

· Ascending· Transverse· Descending· S-shaped sigmoidal

Rectum = Rectum is area for storage of fecesLeads to the anus, the external opening of the alimentary canalDefecation

Functions of the Large Intestine

· Absorption of water· Eliminates indigestible food from the

body as feces· Does not participate in digestion of food· Goblet cells produce mucus to act as a

lubricant

Food Breakdown and Absorption in the Large Intestine

· No digestive enzymes are produced· Resident bacteria digest remaining

nutrients· Produce some vitamin K and B· Release gases

· Water and vitamins K and B are absorbed· Remaining materials are eliminated via

feces

Accessory Organs of the Digestive System

Gallbladder Liver Pancreas

The Liver• Largest gland in the body

(about 3 pounds)• Over 500 functions• Inferior to diaphragm in

RUQ and epigastric area protected by ribs

• R and L lobes– Plus 2 smaller lobes

• Falciform ligament– Mesentery binding liver to

anterior abdominal wall• 2 surfaces

– Diaphragmatic– Visceral

• Covered by peritoneum– Except “bare area” fused to

diaphragm

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Functions of the Liver• Bile production

– Salts emulsify fats, contain pigments as bilirubin

• Storage– Glycogen, fat, vitamins, copper and iron

• Nutrient interconversion• Detoxification

– Hepatocytes remove ammonia and convert to urea

• Phagocytosis– Kupffer cells phagocytize worn-out and dying red and white blood cells,

some bacteria

• Synthesis– Albumins, fibrinogen, globulins, heparin, clotting factors

Role of the Liver in Metabolism

· Several roles in digestion· Detoxifies drugs and alcohol· Degrades hormones· Produce cholesterol, blood proteins

(albumin and clotting proteins)· Plays a central role in metabolism

Gallbladder

• Bile is produced in the liver• Bile is stored in the gallbladder• Bile is excreted into the duodenum when needed (fatty meal)• Bile helps dissolve fat and cholesterol• If bile salts crystallize, gall stones are formed

– Intermittent pain: ball valve effect causing intermittent obstruction – Or infection and a lot of pain, fever, vomiting, etc.

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Figure:- The Gallbladder

Pancreas· Produces a wide spectrum

of digestive enzymes that break down all categories of food

· Enzymes are secreted into the duodenum

· Alkaline fluid introduced with enzymes neutralizes acidic chyme

· Endocrine products of pancreas· Insulin· Glucagons

Pancreas

• Anatomy– Endocrine

• Pancreatic islets produce insulin and glucagon

– Exocrine• Acini produce digestive

enzymes– Regions: Head, body, tail

• Secretions– Pancreatic juice

(exocrine)• Trypsin• Chymotrypsin• Carboxypeptidase• Pancreatic amylase• Pancreatic lipases• Enzymes that reduce DNA

and ribonucleic acid

Processes of the Digestive System

· Ingestion – getting food into the mouth· Propulsion – moving foods from one region of the

digestive system to another· Peristalsis – alternating waves of contraction· Segmentation – moving materials back and forth to aid in

mixing

Processes of the Digestive System· Mechanical digestion

· Mixing of food in the mouth by the tongue· Churning of food in the stomach· Segmentation in the small intestine

· Chemical Digestion· Enzymes break down food molecules into their

building blocks· Each major food group uses different enzymes

· Carbohydrates are broken to simple sugars· Proteins are broken to amino acids· Fats are broken to fatty acids and alcohols

Processes of the Digestive System

· Absorption· End products of digestion are absorbed in

the blood or lymph· Food must enter mucosal cells and then

into blood or lymph capillaries· Defecation

· Elimination of indigestible substances as feces

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DISORDERS OF THE GASTROINTESTINAL SYSTEM

Disorders of the upper GI systemDisorders affecting Ingestion

• ANOREXIA: lack of appetite, could be from emotional or physical factors

• lab tests may be done to assess nutritional status • Medical treatment:supplements may be ordered, TPN or

enteral feedings• Nursing Interventions:

– oral hygiene, clean room, determine cause of nausea and treat, include family and friends(socialization), respect likes and dislikes, education

STOMATITIS

• Inflammation of the oral mucosa (mouth)• Causes: trauma, organisms, irritants, nutritional

deficiency, diseases, chemotherapy• S/S: swelling, pain, ulcerations, excessive salivation,

halitosis, sore mouth• Treatment:• pain relief, removal of causative factor, oral hygiene,

medications, soft bland diet

GINGIVITIS

• Inflammation of the gums• Causes: poor oral hygiene, poorly fitting

dentures, nutritional deficiency• S/S: red, swollen, bleeding gums, painful• Treatment: dental hygiene, prevention of

complications

HERPES SIMPLEX TYPE 1

• Infection affecting the lips and mucous membranes of the mouth

• Causes: Herpes simplex virus• S/S: Vesicles on the mouth, nose or lips, malaise,

edema of surrounding area• Treatment: Antiviral medication(Zovirax), analgesics,

symptomatic relief• Nsg Interventions: Administer meds, keep lesions dry,

provide symptomatic relief

LEUKOPLAKIA

• Abnormal thickening and whitening of the epithelium of the mucous membranes of the cheeks and tongue

• Causes: Chronic irritation • S/S: Thickened white or reddish lesions on the

mucous membrane, lesions can not be rubbed off• Treatment: May be surgically removed or treated

with chemotherapy, meticulous oral hygiene• Interventions: Assess mouth frequently, assist with

oral hygiene, discuss removal of sources of irritation

ORAL CANCER• Malignant lesions may develop on the lips, oral cavity, tongue

and pharynx. Generally squamous cell carcinomas• Causes: high alcohol consumption, tobacco use, external

irritants• S/S: Leukoplakia, swelling, edema, numbness, pain• Diagnosis: biopsy• Treatment:

– Surgery– Radiation or chemotherapy

• depends on the size and location and the lesion• Interventions: consult MD for special mouth care, monitor

respiratory status, keep HOB elevated, administer pain med, assess ability to swallow and talk, assess for infection at incision site, education.

ESOPHAGITIS

• Inflammation or irritation of the esophagus• Causes: Reflux of stomach contents, irritants, fungal

infections, trauma, malignancy, intubation• S/S: heartburn, pain, dysphagia• Treatment: treat underlying cause• Interventions: soft bland diet, administer meds,

elevate HOB, observe for complications

NAUSEA AND VOMITING• Nausea: unpleasant sensation usually preceding vomiting, may

have abdominal pain, pallor, sweating, clammy skin

• Causes: irritating food, infection, radiation, drugs, hormonal changes, surgery, inner ear disorders, distention of the GI tract

• Vomiting: forceful expulsions of stomach contents through the mouth. Occurs when vomiting reflex in the brain is stimulated.

• Projectile vomiting- is forceful ejection of stomach contents.• Regurgitation- gentle ejection of stomach contents without

nausea or retching

Complications and Treatment• May lead to dehydration, metabolic

alkalosis, aspiration• Treatment: Antiemetics( Phenergan,

Dramamine, Scopolamine patch Reglan), IV fluids, NG tube, TPN

• Nursing care: through assessment, keep patient comfortable, offer liquids, position on side, suction setup in the room

GASTRITIS

• Inflammation of the lining of the stomach• ACUTE: excessive intake of food or alcohol.

Food poisoning, chemical irritation• CHRONIC: repeated episodes of acute, H Pylori

Signs/Symptoms and Complications

• Nausea, vomiting, feeling of fullness, pain in stomach, indigestion. With chronic may have only mild indigestion

• changes in stomach lining with decrease in acid and intrinsic factor

( high risk for pernicious anemia)

Treatment

• Treat symptoms, and fluid replacement• Medications: antacids, H2 receptor blockers, B 12

injections, corticosteroids analgesics, antibiotics if H Pylori

• bland diet, frequent meals • Eliminate the cause• surgical intervention• BEST DIAGNOSIS IS GASTROSOPY & BIOPSY

PEPTIC ULCER

• Loss of tissue from the lining of the digestive tract. May be acute or chronic.

• Classified as gastric or duodental (stress- develop 24-48hr. After event)

• CAUSES: drugs, stress, heavy alcohol and tobacco use, infection (H .pylori bacteria) Conditions that cause high gastric acid concentration

TREATMENT

• Drug therapy– Antacids– H2 RECEPTOR BLOCKERS– ANTICHOLINERGICS-Pro-Banthine, Robinul, Bentyl– SUCRALFATE- Carafate– Antibiotics –Flagyl, tetracycline, Biaxin

• treatment goals- relieve symptoms, promote healing, prevent complications and recurrence

STOMACH CANCER• Rare(25,000/yr.), common in males, African American, over 70

and low socioeconomic status. 60% decrease in past 40 yrs.• No S/S in early stages• Late stages S/S: N/V, ascities, liver enlargement, abd. Mass• Mets to bone and lung• 10% survival rate after 5 yrs.• Risk factors: pernicious anemia, chronic gastritis, cigarette

smoking, diet high in starch, salt, salted meat, pickled foods, nitrates

• Treatment: surgery/ chemotherapy/ radiation– subtotal gastrectomy, total gastrectomy

OBESITY

• Increase in body weight, 20% over ideal, caused by excessive fat. Morbid obesity twice ideal

• Causes: heredity, body build, metabolism, psychosocial factors. Calorie intake exceeds demands.

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Treatment and nursing care

• Weight reduction diet• drug therapy, mainly Amphetamines• Surgical procedures:

– Liposuction– Lipectomy– Jaw wiring– Intragastric balloon– Gastric bypass– gastroplasty– jejunoileal bypass

• Nursing care-assessment, diet monitoring, education

DIRRHOEA

• The passage of loose liquid stools with increased frequency, associated with cramping, abd, pain

• Causes; (many), foods, allergies, infections, stress, fecal impaction, tube feedings, medications

• Complications- usually temporary/ can be dehydration, malnutrition

Treatment/Nursing care

• Treatment; GI rest, antidiarrheal drugs(Lomotil, Imodium, Kaolin, Aluminum hydroxide)

• Nursing Care: help determine cause, assessVS, weight, skin turgor, abdominal destention, perianal irritation, skin integrity

CONSTIPATION

• HARD DRY INFREQUENT STOOLS PASSED WITH DIFFICULTY

• Causes: (many),inactivity, ignored urge, drugs,age related changes

• Complications: straining (Valsalva maneuver) and fecal impaction

Treatment/Nursing care

• Laxatives, suppositorys, enemas for prompt results

• stool softeners, increase fluids,dietary fiber• Nursing care: assessment, monitor fluids and

diet, education, check for impaction

Thank you…