Digestive System (Q4,P2) Flashcards
Two Groups of the Digestive System
- Alimentary Canal
- Accessory Digestive Organs
Structures of the Alimentary Canal
- Mouth
- Pharynx
- Esophagus
- Stomach
- Small Intestine
- Large Intestine (colon)
Structures of the Accessory Digestive Organs
- Teeth
- Tongue
- Gallbladder
- Salivary Glands
- Liver
- Pancreas
Digestive Processes
- Ingestion
- Propulsion
- Mechanical Digestion
- Chemical Digestion
- Absorption
- Defecation
9 Abdominal Sections
- Top Row: right hypochondriac, epigastric, left hypochondriac
- Middle Row: right lumbar, umbilical, left lumbar
- Bottom Row: right inguinal, hypogastric, left inguinal
Pertioneum
- Serous membrane
- 2 layers: visceral peritoneum, parietal peritoneum
Visceral Peritoneum
Surrounds digestive organs
Parietal peritoneum
Lines the body wall
Peritoneal Cavity
A slit-like potential space
Layers of the Alimentary Canal Wall
- Same four layers from esophagus to anus
- Mucosa
- Submucosa
- Muscularis Extena
- Serosa
Mucosa
innermost layer of alimentary canal wall
submucosa
external to the mucosa
Muscularis Externa
external to the submucosa
Serosa
- the outermost layer of the alimentary canal wall
- The visceral peritoneum
What is the order that the trocar would pass through the layer of the alimentary canal? (outer to inner)
- Skin
- Muscle
- Serosa (visceral peritoneum)
- muscularis externa
- submucosa
- mucosa
Mouth Muscles
- Mouth: oral cavity
- Lips and cheeks: formed from orbicularis oris and buccinator
Anatomy of the Mouth
The labial and lingual frenulum
The palate – forms the roof of the mouth
Tongue
- Interlacing fascicles of skeletal muscle
- Grips food and repositions and manipulates the food to form a ball called a “bolus”
Deciduous Teeth
- “baby teeth”
- First appear at 6 months of age
- 20 teeth
Permanent Teeth
- Most are present by the end of adolescence
- 32 teeth
4 Types of Teeth
- Incisors.
- Canines.
- Premolars.
- Molars.
Incisors
- front two teeth and the teeth on either side of them
- Each incisor has a single narrow edge, which helps cut into food when you bite
Canines (Eye Teeth)
- four canine teeth: one in each quadrant (upper right, upper left, lower right, lower left)
- help you tear into foods like meat and crunchy vegetables
Premolars (Bicuspids)
- sit between your canines and your molars
- have features of both canines and molars.
- They help tear, crush, and grind food into smaller pieces.
Molars
- 12 molar teeth: three in each quadrant. (including wisdom teeth: without wisdom teeth 8 molars)
- in the very back of your mouth
- main chewing teeth: good for crushing and grinding up your food.
Salivary Glands
- Produce Saliva
- 3 Pairs of salivary glands: parotid, submandibular, sublingual
Pharynx
- Oropharynx and Laryngopharynx: passages for air and food
Esophagus
- Muscular tube
- Begins as a continuation of the pharynx
- Posterior to the trachea
- Joins the stomach inferior to the diaphragm
Cardiac Sphincter
muscle that closes/opens the beginning of the stomach (cardiac orphis)
- sometimes called the lower esophageal sphincter
Stomach
- Site where food (bolus) is churned into chyme
- Protein digestion begins in the stomach
- Secretes pepsin: functions under acidic conditions
Parts and Curvatures of the Stomach
- Fundus
- Cardia
- Body
- Greater Curvature
- Lesser Curvature
- Pylorus
Small Intestine
- Longest portion of the alimentary canal (but more narrow than large intestine)
- Site of most enzymatic digestion and absorption of nutrients
- Three subdivisions: Duodenum, jejunum, and ileum (from proximal to distal)
Duodenum
- Receives digestive enzymes and bile
Main Pancreatic Duct
- a duct joining the pancreas to the common bile duct.
- drains the pancreatic fluid from the pancreas and carries it to the duodenum
Large Intestine
- Absorbs water and electrolytes
- Mass peristaltic movements in the colon force feces toward the rectum
- Small amount of digestion by bacteria
- Digested residue contains few nutrients
Anatomy of the Large intestine
- Divisions: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anal canal
Haustra of the Large Intestine
small pouches caused by sacculation, which give the colon its segmented appearance.
Liver
- Largest gland in the body
- Performs over 500 functions (many metabolic functions)
- Main digestive function: bile production (secretes bile)
Lobes of the Liver
Right, left, caudate, and quadrate
Gallbladder
- a sac located under the liver.
- Found between the Right lobe and the quadrant lobe of the liver
- stores and concentrates bile produced in the liver.
- Expels bile into duodenum
What does bile do?
- emulsifies fats (breaks down fats)
- Bile aids in the digestion of fat and is released from the gallbladder into the upper small intestine in response to food (especially fats).
Pancreas
- A Heterocrine gland: having both an endocrine and an exocrine secretion
Exocrine Function of the Pancreas
- Make, store, and secrete pancreatic enzymes
- Enzymes are activated in the duodenum and aid in the breakdown of nutrients for absorption
Endocrine Function of the Pancreas
- produces insulin and glucagon (hormones)
- regulates blood sugar (glucose)
Insulin
- hormone made by the pancreas
- reduces blood sugar
Glucagon
- hormone made by the pancreas
- increases blood sugar
Endocrine vs Exocrine glands
- Endocrine glands release substances directly into the bloodstream
- exocrine glands release substances to the exterior or into cavities inside the body
