All Flashcards
The alimentary canal extends from the _____ to the _____.
Mouth
Anus
What is the inner most layer of the alimentary canal?
The mucosa or mucus membrane
What does the mucosa do?
Protects the tissue beneath it
Carries on secretion and absorption
Secretes mucus and digestive enzymes
What does the submucosa consist of?
Glands, blood vessels, lymphatic vessels, and nerves
What does the submucosa do?
Nourishes surrounding tissue and carries away absorbed materials
What does the muscular layer do?
Produces movement of the tube
What happens when smooth muscles contract?
The tube diameter decreases
What is the outer covering of the tube?
The serosa or serous layer
What does the Serosa do?
Secretes serous fluid which moistens and lubricates the tube’s outer surface
What does serous fluid do?
Moistens and lubricates the outer surface of the tube
What are the two types of motor functions?
Mixing and propelling movements
When do mixing movements occur?
When the stomach is full and waves of muscular contractions move along the wall from end to end, mixing food with digestive juices
What do the waves of mixing movements do?
Mix food with digestive juices
What do propelling movements including?
A wavelike motion called peristalsis
How does peristalsis occur?
A ring of muscular contractions appears in the wall which push food down the tube
What are the parts of the mouth?
The lips, cheeks, tongue, and palate
What is the oral cavity?
The chamber between the palate and tongue
What does the palate form?
The roof of the mouth of the oral cavity
Where are palatine tonsils located?
In the back of the mouth on either side of the tongue
What are palatine tonsils?
Masses of lymphatic tissue which are found on either side of the tongue in the back of the mouth
What is the purpose of palatine tonsils? However…..?
To protect against infection
They are a common site of infections, and when swollen they can interfere with swallowing and breatning
Explain the parts in cavities in teeth.
Blood vessels and nerves reach this cavity through tubular root canals extending into the root
What does saliva do?
Moistens food particles, helps bind them, dissolves food so that it can be tasted, and begins the chemical digestion of carbohydrates
What is salivary amylase?
An enzyme that splits starch and glycogen molecules into disaccharides
Salivary amylase splits starch and glycogen molecules into disaccharides. What is this?
The first step in the digestion of carbohydrates
What are the 3 stages of swallowing?
The tongue rolls the mixture of the food and saliva into a bolus and forces it into the pharynx
Food is swallowed by a reflex
Food is transported in the esophagus to the stomach by peristalsis
What are the 4 regions of the stomach?
The cardiac, fundic, body, and pyloric regions
What is the cardiac region of the stomach?
The small area near the esophageal opening
What is the fundic region of the stomach?
A temporary storage area
What is the body region of the stomach?
The main part of the stomach which lies between the fundic and pyloric regions
What do gastric glands in the stomach secrete?
3 types of gastric cells: chief cells, parietal cells, and mucus cells
What do chief cells secrete? Parietal cells?
Digestive enzymes
Hydrochloride acid
Gastric cells along with what secrete ______
2 other types of cells
Gastric juices
What is the most important gastric juice and what does it do?
Pepsin begins the digestion of all types of proteins.
How long may fatty foods remain in the stomach?
From 3-6 hours
What passes through the stomach faster than fatty foods? Fastest?
Proteins
Carbs
Where does the sensory impulse for vomiting travel from?
From the vomiting center in the medulla oblongata in the brain
When can a hiatal hernia form?
When a portion of the stomach protrudes through a weakened area of the diaphragm
What is secretin?
A hormone which stimulates the secretion of pancreatic juice
What are 5 functions of the liver?
Converting noncarbohydrates to glucose Metabolizing proteins Storing vitamins A, D, and B12 Filtering blood by removing damaged blood cells Secreting bile
What is bile?
A yellowing liquid that contains bile salts, bile pigments, cholesterol, and electrolytes
What are bile salts?
The most abundant substances in bile which aid in digestion by emulsifying fat
What is jaundice?
A condition that turns skin yellow due to a buildup of bile pigments
How can Hepatitis B spread?
By contact with virus-containing body fluids such as blood, saliva, or semen
Through what can Hepatitis B spread?
By blood transfusions, needles, or sexual activity
What are half of all hepatitis cases?
Hepatitis C
How is Hepatitis primarily spread?
In blood, by sharing needles, razors, blood transfusions
Females can give it to the fetus
What is the major mixing movement of the small intestine?
Segmentation
What is segmentation? What does it do?
When small, ring like contractions occur periodically, cutting chyme into segments
Slows the movement through the small intestines
When does the condition of malabsorption occur?
When the small intestine digests but does not absorb some nutrients
What are symptoms of malabsorption?
Diarrhea, weight loss, weakness, anemia, and vitamin deficiencies
What does the large intestine absorb from chyme? Where does this occur?
Water and electrolytes
In the proximal half of the tube
What does the large intestine do in the distal part of the tube?
Forms and stores feces
What does the large intestine consist of?
The cecum, colon, rectum, and anal canal
What are hemorrhoids?
Enlarged and inflamed rectal veins in the anal column that cause itching, sharp pain, and sometimes bleeding
What are feces?
Materials that were not digested or absorbed, plus water, electrolytes, mucus, and bacteria
How much of feces is water? Where does the coloring come from?
75%
From bile pigments altered by bacterial action
What does the digestive system consist of?
The Alimentary canal, which extends from the mouth to the anus, and several accessory organs, which secrete substances used in the process of digestion
4 Types of teeth:
Central and lateral Incisors, canine (cuspid), premolar (bicuspid) 1st and 2nd, and molar 1st, 2nd, and 3rd
Number of teeth:
4 of each except premolar and third molar in primary teeth
What do incisors do? Canines? Premolar? Molar?
Bite off pieces of food
Grasp and tear food
Grind food particles
Grind food particles
How do gallstones form?
Cholesterol in bile precipitates and forms crystals called gallstones
What is bad about gallstones?
They may enter the common bile duct and block bike flow into the small intestine and cause considerable pain
What is a cholecystectomy?
A surgery in which the gallbladder is removed bcs of gallstones
It can be done with a laparoscope or small little probe on an outpatient
