Digestive System Flashcards
Function of the digestive system:
_____-taking food in, occurs in the mouth.
Ingestion
Function of the digestive system:
____-breaking down food into smaller molecules
*Mechanical Digestion
*Chemical Digestion
Digestion
Function of the digestive system:
Digestion
_____-physical process that breaks food down into smaller pieces but does not change the chemical nature of the food. Converting food into smaller particles increases surface area and mobility.
*Mechanical Digestion
Function of the digestive system:
Digestion:
____-the process of breaking chemical bonds of molecules in food to produce smaller molecules.
Chemical Digestion
Function of the digestive system:
_____-movement of food along the digestive tract
Propulsion
Function of the digestive system:
Propulsion:
____: the process of moving food from the mouth to the stomach commonly known as swallowing.
Deglutition
Function of the digestive system:
Propulsion
____-Involuntary waves of contraction and relaxation of smooth muscles in the wall of the gastrointestinal tract that propels digestive material forward.
Peristalsis
Function of the digestive system:
____-transport of nutrients from the lumen of the gastrointestinal tract to the blood
Absorption
Function of the digestive system:
____-elimination of waste and indigestible substances from the gastrointestinal tract as feces that passes through the anal canal
Defecation
____-also known as the gastrointestinal (G.I.) tract, is a tube extending from the proximal opening of the mouth to the distal opening of the anus, contents of lumen are considered outside of the body.
Alimentary Canal
Part of the Alimentary canal:
____-functions include ingestion, mastication, mixes food with saliva and forms a bolus (rounded mass), early stages of chemical digestion for carbohydrates and fats, voluntary phase of deglutition (swallowing).
Mouth
Part of the Alimentary canal:
____-functions include the pharyngeal phase of deglutition.
Pharynx
Part of the Alimentary canal:
____-functions include the esophageal phase of deglutition.
Esophagus
Part of the Alimentary canal:
____-functions include secretion of acidic gastric juice that is antimicrobial and performs early stages of chemical digestion for proteins, and churning (muscular contractions that mix gastric juice with a bolus) leading to formation of chyme (semi-fluid composed of partially digested food) from a bolus
Stomach
Part of the Alimentary canal:
_____-primary location of chemical digestion and nutrient absorption.
Divided into three major regions:
- Duodenum
- Jejunum
- Ilium
Small Intestine
Part of the Alimentary canal:
Small intestine
Divided into three major regions:
_____– short proximal segment (~20-25cm) that receives chyme from stomach and exocrine secretions from the pancreas and liver/gall bladder. Responsible for most chemical digestion and some nutrient absorption.
Duodenum
Alimentary canal:
Small intestine
Divided into three major regions:
____-long middle segment (2-3 m) responsible for most nutrient absorption. Surface is highly folded with large circular folds called plicae circulares covered in smaller folds called villi.
Jejunum
Small intestine
Divided into three major regions:
____-longest and most distal segment (2.5-3.5 m) responsible for some nutrient absorption, drains into the large intestine. Contains numerous clusters of lymphoid tissue called Peyer’s patches.
Ilium
____-absorbs most of remaining water and some nutrients, forms feces, eliminates feces in the process of defecation.
Large Intestine (colon)
____-assist with digestion
Accessory organs
Accessory organs
____-produce saliva that lubricates food and contains the enzymes (salivary amylase) that initiate chemical digestion of carbohydrates. Also contains enzymes and antibodies that aid with barrier defenses to protect against infection.
Salivary glands
Accessory organs
____-produces digestive enzymes and bicarbonate
Pancreas
Accessory organs
____-produces bile salts which emulsify lipids to aid with chemical digestion and absorption of lipid soluble nutrients
Liver
Accessory organs
____-stores concentrates and releases bile salts
Gallbladder
_____- mastication (chewing) begins mechanical digestion by breaking food into smaller pieces
Teeth
Teeth:
what are the two set we have in a life time called?
Deciduous teeth
and
Permanent teeth
How many Deciduous teeth are there and when do they emerge?
20 teeth, emerge from ages 6 to 24 months
How many permanent teeth are there, and when do they emerge?
32 teeth, most emerge from ages 6-12 yrs, 3rd molar 17-25 yrs
____-named according to shape & function-Incisors (2 per quadrant), Canines (1 per quadrant), Premolars (2 per quadrant replace the deciduous molars) & Molars (3 per quadrant)
Teeth
Structure of a tooth:
____-exposed portion of the tooth
Crown
Structure of a tooth:
____-hardest substance in the body - covers the crown
Enamel
Structure of a tooth:
____-contacts the gingiva (gums)
Neck
Structure of a tooth:
_____-connected to the dental alveolus (tooth socket) by the periodontal ligament.
Root
Structure of a tooth:
____-deep to the enamel, consists of calcified CT & gives the tooth its shape
Dentin
Structure of a tooth
____-blood vessels and nerves, root canals extend into the root
Pulp cavity
Structure of a tooth
____– surrounds the dentin in the roots, attaches the root to the periodontal ligament
Cementum
____-superficial to the masseter muscles, duct opens near 2nd upper molar
Parotid
____-lies on the medial aspect of the mandible, duct opens near base of the lingual frenulum (fold of mucous membrane connecting the tongue to the floor of the oral cavity).
Submandibular
______-lie under the tongue, 10-12 ducts open to floor of the oral cavity.
Sublingual
Esophagus:
_____-innermost layer lining the lumen, mucus membrane epithelium
o Epithelium—non-keratinized, stratified squamous epithelium.
Mucosa
Esophagus:
_____-dense irregular CT layer, contains nervous tissue, large blood vessels, and large lymphatic vessels.
Submucosa
Esopahgus
____-layers of muscle and nervous tissue surrounding the submucosa. Composed of skeletal muscle in the proximal region and smooth muscle through the middle and distal portions.
Muscularis externa
Esopahgus
_____-superficial sheath of dense irregular CT.
Adventitia
Stomach:
____-innermost layer lining the lumen, mucus membrane epithelium
Mucosa
Stomach:
Mucosa
____-Simple columnar epithelium. Folds in to form gastric pits (glands) that contain the cells that secrete gastric juice.
Epithelium
Stomach:
Mucosa
_____-layer of areolar connective tissue, contains numerous blood and lymphatic vessels that transport nutrients following absorption
Lamina propria
Stomach:
Mucosa
____-layer of smooth muscle in the stomach and intestines that forms the border between mucosa and submucosa and contracts to produces folds that increase surface area.
Muscularis interna-
Stomach:
_____-dense CT layer, contains nervous tissue, large blood vessels, and large lymphatic vessels.
Submucosa
Stomach:
____-layers of muscle and nervous tissue surrounding the submucosa. Composed of smooth muscle arranged in three layers.
Muscularis externa
Stomach:
Muscularis externa
_____-deepest layer.
Oblique layer
Stomach:
Muscularis externa
_____-middle layer.
Circular layer
Stomach:
Muscularis externa
_____-superficial layer.
Longitudinal layer
Stomach
____-also known as the visceral layer of the peritoneal membrane this serous membrane forms outermost lining and attaches to the mesentery (folds of the peritoneal membrane)
Serosa
Stomach
Serosa:
o Mesentery of the stomach:
____-between the liver and the lesser curvature of the stomach. Contains the left and right gastric arteries.
Lesser omentum
Stomach
Serosa:
o Mesentery of the stomach:
____-extends from the greater curvature of the stomach and drapes inferiorly over the anterior of the intestines folding up to attach to the transverse colon.
Greater omentum
____-– innermost layer lining the lumen, mucus membrane epithelium. Folds into large folds called plicae circulares (largest in jejunum).
Mucosa
Mucosa
Jejunum
______-Simple columnar epithelium with a brush border of microvilli to increase the surface area for absorption of nutrients. Folds into finger like projections called villi and indentations called intestinal crypts.
Villi are longest in the jejunum
Epithelium
Mucosa
Jejunum
_____-layer of areolar connective tissue, contains numerous blood and lymphatic vessels that transport nutrients following absorption
Lamina propria
Mucosa
Jejunum
____- Contains glands that have ducts connecting to intestinal crypts
Lamina propria
Mucosa
Jejunum:
Lamina propria:
• Numerous submucosal glands in the duodenum known as ______ produce a mucous that protects from the acidity of the chyme entering from the stomach
Brunner’s glands
Mucosa
Jejunum:
Lamina propria:
Contains clusters of _______ that make up the mucosa-associated lymphoid tissue (MALT).
• Numerous Peyer’s Patches are present in the ilium.
lymphocytes
_____-– dense CT layer, contains nervous tissue, large blood vessels, and large lymphatic vessels.
Submucosa
_____-layers of muscle and nervous tissue surrounding the submucosa. Composed of smooth muscle organized into two layers:
Circular layer and the Longitudinal layer
Muscularis externa
Muscularis externa:
What layer is this?
_____-deep layer contraction decreases diameter of the lumen.
Circular layer
Muscularis externa:
What layer is this?
_____-contractions decrease the length of the alimentary canal.
Longitudinal layer
_____-also known as the visceral layer of the peritoneal membrane this serous membrane forms outermost lining and attaches to the mesentery (folds of the peritoneal membrane)
o Mesentery of the small intestine:
*Mesentery proper
Serosa
Serosa
Mesentery of the small intestine:
_____-connects small intestines to the posterior wall of the abdomen. Contains the superior and inferior mesenteric arteries and veins.
Mesentery proper
Where is the liver located?
• Located within the RUQ, inferior to the diaphragm, protected by the ribcage.
What is the structure of the liver?
Four lobes:
Right (larger) and left lobes
Caudate lobe
Quadrate lobe
What structure of the liver is this?
_____-are separated by the falciform ligament (mesentery that connects the liver to the anterior wall of the abdomen).
Right (larger) and left lobes
What structure of the liver is this?
____-on the posterior along the right side of the inferior vena cava.
Caudate lobe
What structure of the liver is this?
____-rectangular shaped lobe immediately to the left of the gallbladder.
Quadrate lobe
Histology of the liver
_____-structural units of the liver, consisting of plates of hepatocytes situated around a central vein
Lobules
Histology of the liver
_____-branch of hepatic portal vein, hepatic proper artery, and bile duct
o Blood from the hepatic portal veins and the hepatic arteries empty into sinusoids then drains through the central vein to hepatic veins exiting the liver.
Portal Triads
Histology of the liver
______-liver cells lining the sinusoids
Absorb and secrete materials into the blood
Produce bile
Hepatocytes
Histology of the liver:
Hepatocytes
_____-narrow channels that carry bile away from the hepatocytes empty into bile ducts at the portal triad
Bile is stored in the gall bladder then secreted into the duodenum to emulsify fats (increases surface area for fat digestion and absorption)
Bile Canaliculi
Path of bile from the liver:
1.______ merge to form common hepatic duct
Right and left hepatic ducts
Path of bile from the liver:
2. Common hepatic duct merges with the ______ coming from the gallbladder to form the common bile duct
cystic duct
Path of bile from the liver:
3. The common bile duct merges with the main pancreatic duct to empty into the _______
duodenum
Where is the pancreas located at?
Located behind the stomach and parietal layer of the peritoneal membrane (retroperitoneal)
Histology of the pancreas
_____-endocrine cells producing hormones
Islets of Langerhans
Histology of the pancreas
_____-clusters of exocrine cells producing the pancreatic juices containing bicarbonate (neutralizes the acidity of chyme entering the duodenum from the stomach) and digestive enzymes.
Pancreatic acini
Histology of the pancreas:
Pancreatic acini:
Pancreatic juice is excreted through the pancreatic ducts into the ____
duodenum.
Colon;
_____-innermost layer lining the lumen, mucus membrane epithelium.
Mucosa
Colon: Mucosa
_____-Simple columnar epithelium with a brush border of microvilli. Contains numerous goblet cells. Infoldings form indentations called intestinal crypts (glands) but there are no villi in the colon.
Epithelium
Colon: Mucosa
_____-layer of areolar connective tissue, contains numerous blood and lymphatic vessels.
Lamina propria
Colon;
____-dense CT layer, contains nervous tissue, large blood vessels, and large lymphatic vessels.
Submucosa
Colon;
_____-layers of muscle and nervous tissue surrounding the submucosa. Composed of smooth muscle organized into two layers:
Muscularis externa
Colon;
Muscularis externa
______-deep layer contraction decreases diameter of the lumen.
Circular layer
Colon;
Muscularis externa
_____-contractions decrease the length of the alimentary canal. Forms three narrow parallel bands called the tenia coli that produce the haustra (bulging pouch like segments of the colon).
Longitudinal layer
Colon;
_____-also known as the visceral layer of the peritoneal membrane, this serous membrane forms outermost lining and attaches to the mesentery (folds of the peritoneal membrane)
o Mesentery of the colon (mesocolon):
Transverse Mesocolon-
Serosa
Colon;
Serosa:
o Mesentery of the colon (mesocolon):
______-connects transverse colon to the posterior wall of the abdomen. Contains the middle colic artery.
Transverse Mesocolon
