The Digestive System Part 1 Flashcards
describe the DIGESTIVE SYSTEM FUNCTIONS
- a LONG TUBE that is OPEN at the BOTH ENDS for the TRANSIT OF FOOD during PROCESSING
- takes MACRONUTRIENTS and turns them into MICRONUTRIENTS
- this allows for ABSORPTION and can be used within the body
- able to use CHEMICAL ENERGY
what are the ORGANS of the DIGESTIVE SYSTEM? more specifically the ALIMENTARY CANAL (GI TRACT) (5)
- ALIMENTARY CANAL (GI TRACT)—
- has the PORTIONS OF;
- esophagus
- stomach
- small intestine
- large intestine
- rectum
- has the PORTIONS OF;
what are the ACCESSORY DIGESTIVE ORGANS? (6)
they are NOT PART OF THE GI TRACT—THEY DO CONTRIBUTE TO FOOD PROCESSING
1. teeth
2. tongue
3. salivary glands
4. liver
5. gall bladder
6. pancreas
describe PROPULSION–SEGMENTATION
- nonadjacent segments of the alimentary canal organs—alternate contract and relax
- MOVES FOOD FORWARD AND BACKWARD
- slows down food and mixing of food
describe PROPULSION–PERISTALSIS
- adjacent segments of the alimentary canal or tract—alternate contract and relax
- MOVES FOOD DISTALLY
describe the PERITONEUM
- the largest serous membrane in the body
- within the ABDOMINAL CAVITY
describe the TWO TYPES OF PERITONEUM
- VISCERAL PERITONEUM (part of serous membrane that TOUCHES THE ORGAN)
- PARIETAL PERITONEUM (lining the abdominal cavity)
-
RETROPERITONEUM:
- found in the BACK —covers the KIDNEY AND PARTS OF LARGE INTEST.
-
STOMACH:
- considered to be INTRAPERITONEAL
what is the MESENTRY? what are our TYPES OF MESENTRY?
- double layer of PERITONEUM—extends to the DIGESTIVE ORGANS from the BODY WALL
- provides ROUTES FOR BV/NERVES/LYMPHATICS to reach the DIGESTIVE VISCERA
-
TYPES:
- GREATER OMENTUM
- LESSER OMENTUM
what are the FUNCTIONS of the MESENTRY (3)?
- FAT DEPOSITION:
- has varying amounts of ADIPOSE TISSUE
- IMMUNE CONTRIBUTION:
- has MILKY SPOTS OF MACROPHAGE COLLECTIONS
- INFECTION AND WOUND ISOLATION:
- can also PHYSICALLY LIMIT the spread of INTRAPERITONEAL INFECTIONS
describe the GREATER OMENTUM
- looks similar to an APRON—drapes off stomach
- COVERS DIGESTIVE ORGANS
- FIRST STRUCTURE WE SEE cutting in
- FUNCTION:
- works as FAT DEPOSITION
- has MALT; helps with INFECTION and WOUND ISOLATION
describe the LESSER OMENTUM
- found on the LESSER CURVATURE OF THE STOMACH
- type of DOUBLE LAYER OF PERITONEUM
definition of PERITONITIS
- peritoneum starts to stick together
- can be caused by abdominal wounds, ulcers, etc..
- LOCALIZED INFECTION
- treated with debridement or antibiotic therapy
describe PERITONEAL DIALYSIS
- use of PATIENT PERITONEUM as MEMBRANE—FLUIDS and OTHER SUBSTANCES to be EXCHANGED FROM BLOOD
- use of CATHETER on patient’s ABDOMEN—FLUID INTRODUCED
- solution is able to enter the ABDOMINAL CAVITY
- CLEAR SOLUTION COMES IN (has DEXTROSE—PULLS WASTE INTO ABDOMINAL CAVITY)
- FLUID IS DRAINED through GRAVITY
what are the LAYERS OF THE GI TRACT?
- states from the ESOPHAGUS to the ANAL CANAL have the same 4 TUNICS
1. MUCOSA
2. SUBMUCOSA
3. MUSCULARIS EXTERNA
4. SEROSA
describe the MUCOSA
- the INNERMOST LAYER
- the MOIST EPITHELIAL MEMBRANE that begins to LINE THE ALIMENTARY CANAL LUMEN from MOUTH TO ANUS
- secretes MUCUS, DIGESTIVE ENZYMES, and HORMONES
- absorbs END PRODUCTS OF DIGESTION
- protects against INFECTIOUS DISEASE
what are the THREE SUBLAYERS OF THE MUCOSA?
- EPITHELIUM
- LAMINA PROPRIA
- MUSCULARIS MUCOSAE
describe the SUBLAYER EPITHELIUM in the MUCOSA
- EPITHELIUM (the mouth, pharynx, esophagus, anal canal)
- made of STRATIFIED SQUAMOUS EPITHELIUM
- withstands TRAUMA
- EPITHELIUM (stomach and intestines)
- made of SIMPLE COLUMNAR EPITHELIUM and MUCUS-SECRETING CELLS (most of tract)
- has MUCUS
- PROTECTION of DIGESTIVE ORGANS FROM ENZYMES
- eases FOOD PASSAGE
- can secrete ENZYMES and HORMONES
- has MUCUS
- made of SIMPLE COLUMNAR EPITHELIUM and MUCUS-SECRETING CELLS (most of tract)
describe ANEMIA
- ANEMIA:
- less production of RBC
- LACK OF INTRINSIC FACTOR:
- necessary for COUPLING with VITAMIN B12 —can be ABSORBED IN THE BODY
- B12 cannot be ABSORBED—PERNICIOUS ANEMIA
describe the SUBLAYER–LAMINA PROPIA in the MUCOSA
- has LOOSE AREOLAR CONNECTIVE TISSUE
- has CAPILLARIES to NOURISH EPITHELIUM
- absorbs DIGESTED NUTRIENTS
-
MALT:
- protection against BACTERIA and OTHER PATHOGENS
describe the SUBLAYER MUSCULARIS MUCOSAE – MUCOSA
- the SCANT LAYER of SMOOTH MUSCLE that produces LOCAL MOVEMENTS of the MUCOSA
- assists in ENHANCING ABSORPTION and SECRETION
describe the SUBMUCOSA
- made up of LOOSE AREOLAR CONNECTIVE TISSUE
- has a RICH BLOOD SUPPLY of BLOOD and LYMPHATIC VESSELS, LYMPHOID FOLLICLES, and NERVE FIBERS
describe the MUSCULARIS EXTERNA
- responsible for PERISTALSIS and SEGMENTATION
- has a CIRCULAR (INNER) and LONGITUDINAL LAYER (OUTER)
describe the SEROSA
- its most OUTERMOST LAYER; known as the VISCERAL PERITONEUM
- within the ESOPHAGUS—serosa replaced by an ADVENTITIA
describe the ENTERIC NERVOUS SYSTEM (ENS)
- the BRAIN OF THE GUT
- runs through the WHOLE SUBMUCOSA—similar to CHICKENWIRE
what is the FUNCTION OF the SUBMUCOSAL AND MYENTERIC PLEXUSES?
part of the ENTERIC NERVOUS SYSTEM
- has the SUBMUCOSAL PLEXUS
- regulates GLANDS and SMOOTH MUSCLE
- has the MYENTERIC PLEXUS
- controls the GI motility through SMOOTH MUSCLE CONTRACTION
- linked to CNS with AFFERENT VISCERAL FIBERS
describe the AUTONOMIC NERVOUS SYSTEM’S ROLE IN DIGESTIVE
- PARASYMPATHETIC
- STIMULATE DIGESTIVE ACTIVITY—rest and digest
- SYMPATHETIC
- INHIBIT DIGESTIVE ACTIVITY—fight or flight
describe the NEURAL REFLEX PATHWAYS
initiated by stimuli INSIDE or OUTSIDE the GASTROINTESTINAL TRACT
- MECHANORECEPTORS + CHEMORECEPTORS (pH, chemicals) + OSMORECEPTORS (stretch, osmolarity)
-
INTRINSIC & EXTRINSIC CONTROLS
- short reflexes— mediated ENTIRELY BY ENS (LOCAL STIMULUS—only INSIDE)
-
long relfexes—respond INSIDE AND OUTSIDE OF GI TRACT (involves the CNS + long nerves)
- CN X—VAGUS NERVE
what are the THREE CONCEPTS that REGULATE GI ACTIVITY?
- DIGESTIVE ACTIVITY – provoked by MECHANICAL and CHEMICAL STIMULI
- EFFECTORS OF DIGESTIVE ACTIVITY: SMOOTH MUSCLE + GLANDS
- NEURONS (INTRINSIC + EXTRINSIC) + HORMONES – CONTROLS DIGESTIVE ACTIVITY
describe the MOUTH
- where food is CHEWED and MIXED WITH ENZYMES
- contains SALIVA—begins the process of DIGESTION
- SWALLOWING PROCESS is initiated
- oral cavity lined by the STRATIFIED SQUAMOUS EPITHELIUM
what are the MOTOR and SENSORY SUPPLY INNERVATIONS of the TONGUE?
- MOTOR SUPPLY INNERVATIONS (movement):
- CN XII—HYPOGLOSSAL NERVE
- SENSORY SUPPLY (taste):
- CN V—TRIGEMINAL NERVE
- CN VII—FACIAL NERVE
describe the TONGUE
composed of INTERLACING BUNDLES of SKELETAL MUSCLE
FUNCTIONS:
- MIXING of FOOD during CHEWING
- FORMATION OF BOLUS
initiation of SWALLOWING
describe the LINGUAL GLAND
- production of LINGUAL LIPASE:
- breakdown of TRIGLYCERIDES
- into FATTY ACIDS and DIGLYCERIDES
- chemical breakdown is already beginning at the oral cavity!
- gets blood from LINGUAL ARTERY—branches from EXTERNAL CAROTID ARTERY
- LINGUAL VEINS:
- drain into the INTERNAL JUGULAR VEIN
- LINGUAL VEINS:
what are the SALIVARY GLANDS (3)?
PAROTID (anterior to ear, the BIGGEST) + SUBMANDIBULAR (below jaw) + SUBLINGUAL SALIVARY GLANDS (below tongue):
function and composition of SALIVARY GLANDS
FUNCTIONS:
- begins to CLEANSE the MOUTH and MOISTEN FOOD
- compacts food into BOLUS
- COMPOSITION:
- 97-99.5% WATER + SLIGHTLY ACIDIC
- has SALIVARY AMYLASE:
- breaks down STARCH
- activated by CHLORIDE IONS
- IMMUNOGLOBULIN Ig A—AQUEOUS SOLUTIONS
- protection from microorganisms
- SEROUS ACINI:
- help to CREATE SALIVA
what ACTIVATES the SALIVATORY NUCLEI?
- seen within the BRAIN STEM (pons/medulla)
- sends IMPULSES along PARASYMPATHETIC FIBERS (via motor fibers of CN VII [facial] + IX [glossopharyngeal]
- XEROSTOMIA—dry mouth
- produce around 1,200—1,500 mL of SALIVA
describe HALITOSIS
- bad breath caused by DECOMPOSING FOOD PARTICULES beginning to ACCUMULATE
- bacteria THRIVES
describe SIALOITHIASIS
production of a SMALL SALIVARY STONE—lodged and backflow of SALIVA
- SWOLLEN—BLOCKED SALIVARY GLAND
- pain before eating
describe MUMPS
- caused by PARAMYXOVIRUS
- common childhood disease—INFLAMMATION OF THE PAROTID GLAND
- MALES—inflammation of testes (ORCHITIS)
- VACCINATION OF MMR (MUMPS, MEASLES, RUBELLA)
describe TEETH
- lies in SOCKETS (ALVEOLI)—adapted for MECHANICAL DIGESTION
- help to TEAR and GRIND GOOD—breaking it down into SMALLER FRAGMENTS
- DENTIN:
- made up of CALCIFIED CONNECTIVE TISSUE—the HARDEST SUBSTANCE IN THE BODY
describe the PHARYNX
- food passes from the mouth into the OROPHARYNX and then into the LARYNGOPHARYNX
- allows for passage of food, fluids, and air
- has STRATIFIED SQUAMOUS EPITHELIUM LINING with MUCUS-PRODUCING GLANDS
describe the ESOPHAGUS
- a COLLAPSIBLE + MUSCULAR TUBE that lies POSTERIOR to the TRACHEA and CONNECTS the PHARYNX to the STOMACH
- around 8-10 inches long
describe the ESOPHAGEAL MUCOSA
- contains STRATIFIED SQUAMOUS EPITHELIUM
- changes to the SIMPLE COLUMNAR at the STOMACH
describe the STOMACH
- J-SHAPED ENLARGEMENT of the GI TRACT
- within the UPPER LEFT QUADRANT
- type of TEMPORARY STORAGE—helps with DIGESTION OF BOLUS TO CHYME
- **INTRINSIC FACTOR B12 ABSORPTION
describe the MUSCULARIS EXTERNA OF THE STOMACH
- has CIRCULAR, LONGITUDINAL, and EXTRA THIRD LAYER—OBLIQUE LAYER
- oblique layer specifically helps in CHURNING FOOD within stomach to turn into CHYME
describe the ANATOMY OF THE STOMACH (6)
- CARDIA (CARDIO PART);
- the BEGINNING OF STOMACH
- union of ESOPHAGUS AND STOMACH
- FUNDUS:
- dome-shaped structure
- underneath DIAPHRAGM
- BODY:
- mid-part of stomach
- PYLORIC:
- has ANTRUM (SUPERIOR PART)
- has PYLORIC CANAL
- has PYLORIC SPHINCTER
- the END OF STOMACH
- the BEGINNING OF DUODENUM
- GREATER CURVATURE:
- the GREATER OMENTUM CONNECTS
- LESSER CURVATURE:
- the LESSER OMENTUM CONNECTS
describe the BLOOD SUPPLY of the STOMACH
- BLOOD SUPPLY:
- CELIAC TRUNK (GASTRIC + SPLENIC BRANCHES)
- VEINS of the HEPATIC PORTAL SYSTEM
describe the STOMACH MUCOSA
- modified as SIMPLE COLUMNAR EPITHELIUM
- secretes TWO-LAYER COAT OF ALKALINE MUCUS
- the surface LAYER begins to TRAP BICARBONATE-RICH FLUID LAYER that is beneath it
- keeps the stomach lining from being eaten away from acid
- secretes TWO-LAYER COAT OF ALKALINE MUCUS
- dotted with GASTRIC PITS—leads into the GASTRIC GLANDS
- GASTRIC GLANDS: produces GASTRIC JUICE
what are the TYPES OF GLAND CELLS in the STOMACH (5)?
- TYPES OF GLAND CELLS:
- glands within the FUNDUS and BODY produce most GASTRIC JUICE
- glands include SECRETORY CELLS:
- MUCOUS NECK CELLS
- PARIETAL CELLS
- CHIEF CELLS
- ENTEROENDOCRINE CELLS
- NONENTEROENDOCRINE CELLS
what does the MUCOUS NECK CELL SECRETE?
- MUCUS (protective lining)
- BICARB (forms HCOS–protective barrier)
what does the PARIETAL CELLS secrete?
- GASTRIC ACID (HCI–helps to DENATURE PROTEINS and ACTIVATE PEPSIN + KILL BACTERIA)
- INTRINSIC FACTOR (absorbs B12 and CALCIUM)
what does the ENTEROCHROMAFFIN-LIKE and ENTEROCHROMAFFIN CELLS SECRETE?
HISTAMINE—secreted by ENTEROCHROMAFFIN-LIKE CELLS; stimulates our G CELLS — that secretes GASTRIN/ACID
SEROTONIN—also secreted by ENTEROCHROMAFFIN CELLS
what does the CHIEF CELLS secrete?
- PEPSINOGEN – digests PROTEINS
- GASTRIC LIPASE
- CHYMOSIN – coagulates MILK in stomach
what does the D CELLS (ENTEROENDOCRINE CELL) secrete?
SOMATOSTATIN (inhibits ACID)
what does the G CELLS (ENTEROENDOCRINE CELLS) secrete?
GASTRIN (stimulates ACID)
what is the ONLY STOMACH FUNCTION essential to LIFE?
-
the ONLY STOMACH FUNCTION ESSENTIAL TO LIFE;
- secretion of INTRINSIC FACTOR for VITAMIN B12 ABSORPTION
describe the REGULATION OF GASTRIC SECRETION–NEURAL+ HORMONAL MECHANISMS
- NEURAL MECHANISMS:
- VAGUS NERVE STIMULATION—INCREASES SECRETION
- SYMPATHETIC NERVE STIMULATION—DECREASES SECRETION
- HORMONAL MECHANISMS:
- GASTRIN— stimulates ENZYME AND HCI SECRETION
- GASTRIN ANTAGONISTS—secreted by SMALL INTESTINE
definition of EMESIS
vomiting
- due to EXTREME STRETCHING
- showcases of INTESTINAL IRRITANTS, BACTERIAL TOXINS, EXCESSIVE ALCOHOL, SPICY FOOD, or CERTAIN DRUGS
what are the PHASES OF GASTRIC SECRETION?
- CEPHALIC PHASE (REFLEX PHASE):
- triggered by the SMELL, SIGHT, or THOUGHT OF FOOD
- *remember each phase has STIMULATORY AND INHIBITORY PARTS
- GASTRIC PHASE:
- the stomach begins to DISTEND and activation of STRETCH RECEPORS
- activation of LONG AND SHORT REFLEXES
- INTESTINAL PHASE:
- BRIEF STIMULATION and followed by INHIBITION
- INHIBITORY EFFECT OVERRIDES—don’t want intestines to be overfilled
