Chapter 14 Digestive System Flashcards

1
Q

Organs of the Digestive System

A
  • Two main groups
    • Alimentary canal (gastrointestinal or GI tract [gastrointestinal tract)– continuous coiled hollow tube
    • Accessory (things that help digestion) digestive organs
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2
Q

Organs of the Alimentary Canal (GI Tract)

A
  • Pathway from mouth to anus (food passes through)
    • Mouth
    • Pharynx
    • Esophagus
    • Stomach
    • Small intestine (97% of chemical digestion)
    • Large intestine
    • Anus
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3
Q

Mouth (Oral Cavity) Anatomy

A
  • Lips (Labia)– Protect the anterior opening
    • Cheeks– Form the lateral walls– Buccal cavity
    • Hard palate- forms the anterior roof
    • Soft palate- forms the posterior roof
    • Uvula- Fleshy projection of the soft palate (Lymph tissue)
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4
Q

Mouth Physiology

A
  • Mastication: Chewing of food
  • Mixing masticated food with saliva (Bolus)
  • Initiation of swallowing by the tongue
    • Tonge rolls back
    • Larynx rises
    • Constriction
    • Deglutition (swallowing)
  • Allows for the sense of taste
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5
Q

Pharnyx Anatomy

A
  • Nasopharynx: Not part of the digestive system
  • Oropharynx: Posterior to oral cavity
  • Laryngopharynx: Below the oropharynx and connected to the esophagus
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6
Q

Teeth (Function)

A
  • Function is the masticate (chew) food
  • Humans have two sets of teeth
    • Deciduous (baby or “milk” teeth)
    • 20 teeth are fully formed by age two
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7
Q

Permanent Teeth

A
  • Replace deciduous teeth between the ages of 6 & 12
    • A full set of 32 teeth, but some people do not have wisdom teeth (third molars)
    • If they do emerge, the wisdom teeth appear between ages 17- 25
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8
Q

Classifications of Teeth

A
  • Incisors: cutting
  • Canines- tearing or piercing
  • Premolars- grinding
  • Molars – grinding
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9
Q

Regions of the Tooth

A
  • Crown: Exposed part
  • Neck: region in contact with gum
  • Root: attaches tooth to periodontal membrane
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10
Q

Crown

A
  • Enamel- hardest substance in the body
    • Dentin- found deep to the enamel and forms the bulk of the tooth
    • Pulp cavity: contains connective tissue, blood vessels, and nerve fibers
    • Root canal: where the pulp cavity extends into the root
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11
Q

Neck

A
  • Region in contact with the gum

- Connects crown to root

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12
Q

Root

A
  • Cementum- Covers outer surface

- attaches the tooth to the periodontal membrane

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13
Q

Salivary Glands

A
  • Three pairs of salivary glands empty secretions into the mouth
    • Parotid glands: In front of the ear
    • Submandibular Below the mandible (anterior)
    • Sublingual glands: below the tongue (Posterior)
      • Sublingual is in back of the submandibular
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14
Q

Saliva

A
  • 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
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15
Q

Pharynx Physiology

A
  • 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: wave like contractions)
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16
Q

Esophagus Anatomy and Physiology

A
  • Anatomy
    • About 10 inches long
    • Runs from pharynx to stomach through the diaphragm
  • Physiology
    • Conducts food by peristalsis (slow rhythmic squeezing)
    • Passageway for food only (respiratory system branches off after the pharynx)
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17
Q

Layers of the Alimentary Canal Organs

A
  • Mucosa
  • Submucosa
  • Muscularis Externa
  • Serosa
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18
Q

Mucosa

A
  • Innermost, moist membrane consisting of -Surface epithelium
    - Small amount of connective tissue (lamina propria)
    - Small smooth muscle layer
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19
Q

Submucosa

A
  • Just beneath the mucosa

- Soft connective tissue with blood vessels, nerve endings. and lymphatics

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20
Q

Muscularis Externa

A
  • Smooth muscle
  • Inner circular layer
  • Outer longitudinal layer
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21
Q

Serosa

A
  • Outermost layer of the wall that contains fluid-producing cells
    - Visceral peritoneum- outermost layer that is continuous with the innermost layer
    - Parietal peritoneum- innermost layer that lines the abdominopelvic cavity
22
Q

Alimentary Canal Nerve Plexus

A
  • Bundle of nerves
  • Two important nerve plexuses serve the alimentary canal
  • Both are part of the autonomic nervous system
    • Submucosal nerve plexus
    • Myenteric nerve plexus
  • Function is to regulate mobility and secretory activity of the GI tract organs
23
Q

Small Intestine

A
  • The body’s major digestive organ (19-21 feet)
  • Site of nutrient absorption into the body
  • Function: Chemical digestion
  • Muscular tube extending from the pyloric sphincter to ileocecal valve
  • Suspended from the posterior abdominal wall by the mesentery(tissue)
24
Q

Chemical Digestion of the Small Intestine

A
  • Chemical digestion begins in the small intestine
  • Enzymes are produced by
    • Intestinal glands
    • Pancreas
  • Pancreatic ducts carry enzymes to the small intestine
  • Bile, formed by the liver, enters via the common bile duct (emulsification)
25
Q

What do certain nutrients break down to?

A

Protein–> Amino acids
Carbohydrates–> Monosaccharides
Lipids–> Fatty acids and glycerol
Nucleic acids–> nucleotides

26
Q

Small Intestine Anatomy

A
  • Three structural modifications that increase surface area
    • Microvilli- Tiny projections of the plasma membrane (create a brush border appearance)
    • Villi- fingerlike structures formed by the mucosa
    • Circular folds (plicae circulares)– deep folds of mucosa and submucosa
27
Q

Lacteal

A
  • absorbs fatty acids and glycerol
  • which makes lymph (tissue fluid)
  • Lymph makes antibodies
28
Q

Intestinal Juices

A
  • sucrase (works on sucrose to give u glucose)
  • lactase (works on lactose–> glucose)
  • maltase (works on maltose to glucose)
29
Q

Subdivisions of the Small Intestine

A
  • Duodenum 1 ft
    • Attached to the Stomach
    • Curves around the head of the pancreas
  • Jejunum (8-10 feet)
    • Attaches anteriorly to the duodenum
  • Ileum (longest part)
    • Extends from jejunum to large intestine
30
Q

Stomach Anatomy

A
  • Located on the left side of the abdominal cavity
  • Food enters at the cardioesophageal sphincter
  • Food (chyme) empties into the small intestine at the pyloric sphincter (valve)
31
Q

Regions of the Stomach

A
  • Cardiac region: near the heart
    • Fundus: expanded portion lateral to the cardiac regions
    • Body: midportion
    • Pylorus- funnel-shaped terminal end
32
Q

Rugae

A

-Internal folds of mucosa

33
Q

External Regions of the Stomach

A
  • Lesser curvature: concave (curving in) medial surface

- Greater curvature: convex (curving out) lateral surface

34
Q

Layers of the Peritoneum Attached to the Stomach

A
  • Lesser omentum: attaches the liver to the lesser curvature
    • Greater omentum: attaches the greater curvature to the posterior body wall
      • Contains fat to insulate, cushion, and protect abdominal organs
      • Has lymph nodules containing macrophages
35
Q

Stomach Physiology

A
  • Temporary storage tank for food
  • Site of food breakdown
  • Chemical breakdown of protein begins
  • Delivers chyme (processed food) to the small intestine (to turn into chyle)
36
Q

The Stomach can absorb…?

A
  • Alcohol

- Asprin

37
Q

Structure of the Stomach Mucosa

A
  • Mucosa is simple columnar epithelium
  • Mucous neck cells- produce a sticky alkaline mucus
  • Gastric glands- situated in gastric pits and secrete gastric juice (2.0 pH)
  • Chief cells- produce protein-digesting enzymes (pepsinogens)
  • Parietal cells- produce hydrochloric acid
  • Enteroendocrine cells- produce gastrin (hormone)
38
Q

Large Intestine

A
  • Large in diameter, but shorter in length, than the small intestine
  • Frames the internal abdomen
39
Q

Amylase

A
  • Enzyme

- Turns a starch into maltose

40
Q

Peristalysis

A

-Wave like movement of food (bolus) through the pharynx

41
Q

Digestive System Functions

A
  • Ingestion- Taking in food
  • Digestion- breaking food down both physically and chemically
  • Absorption– movement of nutrients into the bloodstream
  • Defection- rids the body of indigestible waste
42
Q

What is Neutralized Chyme called?

A

-Chyle

43
Q

Cecum and Appendix (Large Intestine Anatomy)

A
  • Cecum: Saclike first part of the large intestine
  • Appendix:
    • Accumulation of lymphatic tissue that sometimes becomes inflamed (appendicitis)
    • Hangs from the cecum
44
Q

Colon (Large Intestine Anatomy)

A
  • Ascending: travels up right ride of abdomen
    • Transverse: travels across the abdominal cavity
    • Descending: travels down the left side
    • Sigmoid: enters the pelvis
45
Q

Rectum and Anus (Large Intestine Anatomy)

A
  • Rectum and anal cavity: also in pelvis
  • Anus: Opening of the large intestine
    • External anal sphincter- formed by skeletal muscle and under voluntary control
    • Internal involuntary sphincter- formed by smooth muscle
    • These sphincters are normally closed except during defecation
46
Q

Large Intestine Anatomy

A
  • No villi present
  • Goblet cells produce alkaline mucus which lubricates the passage of feces
  • Muscalaris externa layer is reduced to three bands of muscle called teniae coli
  • These bands cause the wall to pucker into haustra (pocket-like sacs)
47
Q

Parts of the Large Intestine

A
  • Cecum
  • Appendix
  • Colon
  • Rectum
  • Anus
48
Q

Pancreas

A
  • Found posterior to the parietal peritoneum
  • Extends across the abdomen from spleen to duodenum
  • 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 coming from the stomach
  • Hormones produced by the pancreas
    • Insulin (controls sugar level of blood)
    • Glucagon (helps stabilize low blood-sugar levels)
49
Q

Liver

A
  • Largest gland in the body
  • Located on the right side of the body under the diaphragm
  • Consists of four lobes suspended from the diaphragm and the abdominal wall by the falciform ligament-Connected to the gallbladder via the common hepatic duct
50
Q

Muscles for Chewing

A
  • Buccinator
  • Temporalis
  • Masseter
51
Q

Peritoneum lines???

A

-The cavity