A & P 3 Flashcards
Digestion
mechanical and chemical breakdown of foods so that nutrients can be absorbed by cells.
6 essential activities
ingestion, propulsion, mechanical breakdown, digestion, absorption, defecation
2 types of movement
Peristalsis, Segmentation
Peristalsis
Adjacent segments of alimentary tract organs alternately contract and relax, moving food along the tract distally.
Segmentation
Nonadjacent segments of alimentary tract organs alternately contract and relax, moving food forward then backward.
Food mixing and slow food propulsion occur.
Peritoneum (visceral and parietal)
Peritoneum-serous membrane of abdominal cavity
Visceral Peritoneum:on external surface of most digestive organs
Parietal Peritoneum:lines body wall
Peritoneal Cavity
Between two peritoneums
Fluid lubricates mobile organs
Messentaries
Lesser Omentum, Mesentary, Greater Omentum
Peritonitis
Inflammation of peritoneum
Causes by e.g., piercing abdominal wound, perforating ulcer, ruptured appendix Treated with debris removal and antibiotics
Hepatic portal Circulation
Drains nutrient-rich blood from digestive organs
Delivers it to the liver for processing
Alimentary Canal
muscular tube about 9 meters long that passes through the body’s ventral cavity.
4 layers of the alimentary canal
Inner: Mucosa
submucosa
muscular
Outer: serosa
Mucosa
lined with epithelium attached to connective tissue; it protects tissues of the canal and carries on secretion and absorption.
Lumen
space inside the intestine
Submucosa
loose connective tissue housing blood lymph vessels and nerves; it nourishes the surrounding layers of the canal.
muscular layer
consists of inner circular fibers and outer longitudinal fibers that propel food through the canal.
Serosa
composed of the visceral peritoneum that protects underlying tissues and secretes serous fluid to keep the canal from sticking to other tissues in the abdominal cavity.
Mixing Movements
occurs when smooth muscle contracts in small sections of the tube.
In the small intestine segmentation aids by alternatively contracting and relaxing the smooth muscle
Propelling Movements
also called peristalsis; is caused by contraction behind a mass of food as relaxation allows the mass to enter the next segment of the tube
The first portion of the alimentary canal + the 4 part
The Mouth
1. teeth
2. tongue
3. tonsils
4. salivary glands
Salivary Glands
secrete saliva which moistens and dissolves food particles, binding them together
What type of cells do salivary glands contain
They contain serous cells that produce salivary amylase.
They also contain mucous cells that produce lubricating and binding mucous
What type of stimulation do salivary glands receive
They receive parasympathetic stimulation
3 Major Salivary Glands
- Parotid Glands
- Submandibular Glands
- Sublingual Glands
Parotid Glands
lye in front of the ear
largest salivary gland
secretes a clear watery fluid rich in amylase
Submandibular Glands
located on the floor of the mouth
secrete a viscous fluid
Sublingual Glands
inferior to the tongue
smallest salivary gland
secretes a thick and stringy saliva
Pharynx
connects the nasal and oral cavities with the larynx and esophagus.
3 portions
nasopharynx (top portion)
oropharynx
Laryngopharynx(bottom portion)
3 stages of swallowing
- food is mixed with saliva forming a bolus and voluntarily being forced into the pharynx with the tongue
- Sensory receptors in the pharynx sense food, which triggers swallowing reflexes
- Peristalsis transports the food in the esophagus to the stomach
Esophagus
a straight collapsible passageway leading to the stomach
Lower esophageal sphincter
helps to prevent regurgitation of the stomach contents into the esophagus
Stomach
J-shaped muscular organ that receives and mixes food with the digestive juices, and propels food to the small intestine
5 divisions of the stomach
Cardia, fundus, body region, pylorus, and a pyloric canal
Gastric Glands contain what types of cells
3 types of secretory cells
1. Mucous cells
2. Chief cells
3. Parietal cells
Mucuos cells in the stomach
produces mucous that protects the stomach lining
Chief cells
secrete pepsin(to digest protein) as inactive pepsinogen, which is activated when it comes in contact with hydrochloric acid
Parietal cells
secrete hydrochloric acid
intrinsic factor
another component of gastric juice;
it is required for B12 absorption from the small intestine
Gastric Juice
products of mucous cells, chief cells, and parietal cells make up gastric juice
Mixing and Emptying actions
- Following a meal, mixing actions of the stomach turn the food into chyme and pass it toward the pyloric region using peristalsis
Pancreas
has an exocrine function of producing pancreatic juice that aids in digestion
pancreatic acinar cells
produces pancreatic juice and makes up the bulk of the pancreas; it eventually gives rise to the pancreatic duct
Liver
reddish brown; the body’s largest internal organ and is separated by hepatic lobules
What separates hepatic cells
hepatic sinusoids
Kupffer cells
carry on phagocytosis in the liver
