A&P Chapter 8 (Week 3)

digestive system (GI)

consists primarily of the gastrointestinal tract

upper GI tract consists of

the mouth, pharynx, esophagus, stomach

lower GI tract consists of

small intestine, large intestine, rectum, anus

gastrointestinal (GI) tract

part of the digestive tract below the diaphragm

accessory digestive glands

salivary glands, liver, pancreas

palate

roof of the mouth

hard palate

anterior portion of the palate

soft palate

flexible posterior portion; during swallowing, closes off the nasal passage

uvula

hangs from the free edge of the soft palate; plays a role in some speech sounds

maxillary arch

upper jaw; bones of the lower surface of the skull

mandibular arch

lower jaw; separate bone; only movable component of the joint

incisors and canines

teeth used for biting and tearing

molars

teeth used for chewing and grinding

gingiva (gums)

mucous membrane; covers the bone of the dental arches and surrounds the neck of the teeth

primary dentition

baby teeth; 20 teeth that are replaced by permanent teeth

permanent teeth

32 teeth designed to last a lifetime

saliva

colorless liquid maintains moisture in the mouth; contains digestive enzyme amylase

lower esophageal sphincter (cardiac sphincter)

muscular ring between the esophagus and stomach, opens to allow the flow of food into the stomach, closes to prevent the stomach contents from regurgitating

trachea

tube that transports air to and from the lungs; lies anterior to the esophagus

larynx

voice box

pyloric sphincter

ring-like muscle at the stomach base; controls the flow of partially digested food

chyme

digested food

pyloric canal

canal connecting the stomach to the small intestine

rugae

folds of the mucosal lining; allow the stomach to increase/decrease in size; glands within the folds produce gastric juices

duodenum

1st part of the small bowel

jejunum

2nd part of the small bowel; part of the duodenum that turns downward

ileum

3rd part of the small bowel; connects small bowel to the cecum (1stpart of large bowel)

ileocecal orifice (ileocecal valve/sphincter)

the entry of the small bowel into the large bowel; prevents food from re-entering the small bowel

vermiform appendix (appendix)

hangs from the lower portion of the cecum; no known physiologic purpose; said to have help with immune system

large bowl contains

vermiform appendix, cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum

cecum

pouch on the right side of the abdomen; start of the large bowel

ascending colon

travels superior from the cecum to the posterior of the liver

transverse colon

passes transversely across the abdominal cavity from right to left toward the spleen

descending colon

travels inferiorly on the left side of the abdominal cavity to the sigmoid colon

sigmoid colon

s-shaped structure that continues from the descending colon superiorly and joins the rectum inferiorly

rectum

widest division of the large intestine; ends at the anus

anorectal

refers to the anus and rectum as a single unit

The Liver

removes toxins from the blood, turns food into fuel, uses bile to aid digestion of fats

The Biliary Tree

provides channels through which bile is transported, small ducts join together like branches

The Gallbladder

located under the liver, stores and concentrates bile, contracts when bile is needed, forcing bile out through the biliary tree

The Pancreas

soft, oblong gland, located behind the stomach, produces and secretes pancreatic juices that aid in digestion (exocrine), aids in digestion and plays a role in the endocrine system

digestion

process by which complex foods are broken down into nutrients

digestive enzymes

responsible for breakdown of foods

nutrients

primary or macronutrients; provide the body with calories, carbohydrates, fats, and proteins

micronutrients

required only in small amounts, vitamins and minerals

metabolism

includes all of the processes involved in the body’s use of nutrients

absorption

process of transporting completely digested nutrients to the cells throughout the body

villi

finger-like projections that cover the mucosa lining the small intestine; absorb nutrients directly from the digestive system into the bloodstream

mastication (chewing)

breaks food down into smaller pieces, mixes it with saliva, and prepares it to be swallowed

bolus

mass of food that has been chewed and is ready to be swallowed

peristalsis

series of wave-like contractions of the smooth muscles; moves food downward with the help of gravity

gastric juices

hydrochloric acid

chyme

semifluid mass of partly digested food; passes out of the stomach, through the pyloric sphincter, and into the small intestine

duodenum

chyme is mixed with pancreatic juice and bile, bile breaks apart large fat globules, pancreatic juices digest fats through emulsification action

small intestine

converts food into usable nutrients completed as chyme is moved through the small intestine by peristaltic action

jejunum

secretes large amounts of digestive enzymes; continues the process of digestion

defecation(bowel movement) (BM)

evacuation or emptying of large intestines

feces

solid body waste or stool; expelled through the rectum or anus

gut microbiota

billions of bacteria present in the large intestine; protect against infection and help maintain the immune system

borborygmus

rumbling noise; movement of gas in the intestine

flatulence (flatus or fart)

pass of gas

canker sores

gray-white pits with a red border in the soft tissues lining the mouth; associated with stress, certain foods, or fever

oral thrush

fungal infection in the mouth caused by candida albicans

trismus (lockjaw)

any restriction to the opening of the mouth

xerostomia (dry mouth)

lack of adequate saliva; diminished salivary gland secretions

cleft lip

birth defect; deep groove of the lip running upward to the nose; failure of this portion of the lip to close during prenatal development

cleft palate

failure of the palate to close during the early development of the fetus; can involve the upper lip, hard palate, and/or soft palate; if not corrected, makes it difficult for the child to eat and speak

bruxism

involuntary grinding of the teeth that usually occurs during sleep

dental caries (tooth decay)

caused by bacteria that destroy the enamel and dentin of the tooth

dental plaque

consists of bacteria and bacterial by-products; forms near the gums and between the teeth; cause of dental caries and periodontal disease

edentulous

without teeth, describes the situation after natural permanent teeth have been lost

halitosis

bad breath; can be caused by dental diseases or respiratory or gastric disorders

malocclusion

any deviation from the normal positioning of the upper teeth against the lower teeth

dental calculus (tartar)

dental plaque that has calcified (hardened) on the teeth

gum recession

shrinking of gingival tissue often associated with aging

gingivitis

earliest stage of periodontal disease; inflammation affects only the gums

dysphagia

difficulty in swallowing

gastroesophageal reflux disease (acid reflex)

upward flow of acid from the stomach into the esophagus

Barrett’s esophagus

cells in the epithelial tissue of the esophagus are damaged by chronic acid exposure

fundus

superior part of the stomach

body

major central part of the stomach

antrum

inferior portion before the pylorus of the stomach

pylorus

sphincter opening into the small bowel of the stomach

pyrosis (heartburn)

burning sensation in the chest; return of acidic stomach contents into the esophagus

esophageal varices

enlarged, swollen veins at the lower end of the esophagus; can cause severe bleeding if one of these veins ruptures

hiatal hernia

a portion of the stomach protrudes upward into the chest, through an opening in the diaphragm

gastritis

common inflammation of the stomach lining; can cause nausea and vomiting

gastroenteritis

inflammation of the mucous membrane lining the stomach and intestines

gastroparesis

gastric motility slows down; causes delayed gastric emptying

peptic ulcer disease

sores that affect the mucous membranes of the digestive system, can be found in various places in the GI tract

perforated ulcers

complication of a peptic ulcer; the ulcer erodes through the entire thickness of the organ wall

cachexia

physical wasting away due to the loss of weight and muscle mass

dehydration

fluid loss exceeds fluid intake; disrupts a body’s normal electrolyte balance

failure to thrive (FTT)

when an infant or child does not grow as expected

malabsorption

small intestine cannot absorb nutrients from food that passes through it

malnutrition

lack of proper food or nutrients in the body

body mass index (BMI)

ratio of weight in kilograms divided by height in meters squared

severe obesity

having a body mass index value greater than 40

aerophagia

excessive swallowing of air while eating or drinking

dyspepsia (indigestion)

pain or discomfort during the digestion process