Digestive System Flashcards by Samuel Revilla

Digestive/Alimentary Tract (7)

• Mouth
• Pharynx
• Esophagus
• Stomach
• Small intestine
• Large Intestine
• Anus

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Accessory Organs (6)

• Teeth
• Tongue
• Salivary Glands
• Liver
• Pancreas
• Gallbladder

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It is a tube extending from the mouth to the anus also called Gastrointestinal tract/Alimentary tract

Digestive tract

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These organs are primarily glands that secrete fluids into the digestive tract

Accessory Organs

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Performs the vital tasks of transporting food into chemicals that cells can use for energy. Breaks down food into its simplest components after which it absorbs the components so they can be distributed equally throughout the body

Digestive system

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Study of digestive tract or diagnosis of its diseases is called

Gastroenterology

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Functions of Digestive system (8)

• ingestion
• mastication
• propulsion (swallowing, peristalsis, mass movements)
• mixing
• secretion
• digestion
• absorption
• elimination

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Intake of solid or liquid into the stomach

Ingestion

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Normal route of ingestion is through

Oral cavity

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Is the process by which the teeth chew food in the mouth. The start of mechanical digestion in the process of digestion.

Mastication

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We masticate because

Digestive enzymes cannot easily penetrate solid food particles. They can only work effectively if the particles are or if the food is in a particulate state

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Movement of food from one end to the other

Propulsion

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Total time it takes for food to travel the length of the digestive tract is usually

24-36 hours

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Swallowing is also known as

Deglutition

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Movement of liquids or a soft mass of food and liquid called the bolus from the oral cavity to the esophagus. Done voluntarily

Swallowing

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Mixture of masticated food and digestive enzymes/salivary enzymes

Bolus

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Muscular contractions that propels materials through most of digestive tract. Consists of a wave of relaxation of the circular muscles followed by a wave of strong contraction of the circular muscles behind the bolus

Peristalsis

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Movement that produces peristalsis is

Peristaltic waves

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Contractions that move materials in some parts of the large intestine to the anus

Mass movements

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Some contractions do not propel food from one end of the digestive tract to the other but rather move it back and forth within the digestive tract to mix it with secretions and help break it into smaller pieces

Mixing

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As food moves to the digestive tract secretions are added to help it lubricate, liquefy buffer and digest the food as it moves through the digestive tract.

Secretion

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Secretion called ______ that is distributed throughout the digestive tract. Function is to lubricate the lining of the tract. It also has the function to protect the epithelial cells of the digestive tract from mechanical abrasion caused by food and stomach acid and digestive enzymes

Mucus or mucin

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Breakdown of large organic molecules into their component parts. Example we have carbohydrates into monosaccharides, proteins into amino acids, triglycerides into fatty acids and glycerol

Digestion

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One unit of sugars only

Monosaccharides

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Mechanical digestion

Involves the mastication and mixing of food by your peristaltic waves/movements

Chemical digestion

Accomplished by digestive enzymes secreted along the digestive tract

Movement of molecules out of digestive tract and into the blood or lymphatic system. It occurs by the type of molecule involved

Absorption

The process by which the waste products of digestion are removed from the body. During this process, which occurs primarily in the large intestine, water and salts are reabsorbed and changing the material in the digestive tract from liquefy to semi solid, this semi solid waste is called feces

Elimination

Feces are eliminated through the process of

Defecation

Gastrointestinal tract is composed of 4 tissues

• mucosa • submucosa • muscularis • serosa

Innermost layer. Consists of 3 layers of its own. Function is the secretion of mucus, digestive enzymes and hormones, absorption of end products and protection against infectious diseases

Mucosa

3 layers of mucosa

• layer of loose connective tissue aka lamina propria • thin layer of smooth muscle aka muscularis mucosae • inner layer of epithelium

Thicker layer of connective tissue and it contains glands, blood vessel, lymphatic vessels, and nerves.

Submucosa

Absorb and transports nutrients and some elastic fibers help maintain each of the organ

Blood vessels

Regularly contracts and relaxes to propel the food and it usually consists of two layers of smooth muscle: an inner layer encircles the tract and an outer layer that runs longitudinally

Muscularis or Muscularis externa

Segmentation and peristalsis of digested food along the tract are regulated by the

Myenteric nerve plexus

Outermost layer and covers the portion of the digestive tract within peritoneal cavity. Reduces the friction as the digestive system organs slide across one another

Serosa or visceral peritoneum

Attaches/anchors them (stomach and intestine) in place. Layer of visceral peritoneum that suspends the digestive organs within the abdominal cavity while also anchoring them loosely to the abdominal walls. They have their own blood vessels, nerves, lymphatic vessels, and lymph nodes that supply the digestive tract. Contributes to the immune system for the digestive tract

Mesentery

Accumulated fluid in peritoneal cavity is called

Ascides

Oral or buccal cavity. Surrounded by lips and bordered on each side to the by the cheeks. The edgy way to the digestive tract and where the digestion begins. Both mechanical and chemical digestion occurs here

Mouth

Muscular structures formed by the orbicularis oris muscle and connective tissue. Protects the anterior opening of the oral cavity

Lips

Forms the floor of the mouth. It repositions the food in the mouth during chewing. Contains taste buds with projections called lingual papillae. Skeletal muscles covered by a mucous membrane contains lingual papillae

Tongue

Formed by portions of the maxillae and palatine bones. Separates the mouth from the nasal cavity

Hard palate

Consists mostly of skeletal muscles and forms an arch between the mouth and nasopharynx

Soft palate

Finger like projection of soft palate and extends inferiorly from its posterior marking. Come shaped process. Hangs downward from the soft palate

Uvula

Straight line below the tongue. Anchors the tongue to the floor of the mouth. Fold of mucous membrane and it consists of numerous superficial blood vessels that populate the floor of the mouth

Lingual frenulum

Digestion begins when food enters the mouth and is chewed; a process called mastication. Also allows food to become moistened with saliva

Teeth

How many permanent or secondary teeth does the adult mouth have

2 dental arches

• maxillary arch • mandibular arch

4 types of teeth

• incisor • canine • premolars • molars

On the upper teeth on one side we have:

2 incisor 1 canine 2 premolars 3 molars If in total: 4 incisors 2 canines 4 premolars 6 molars

3rd molar is called _____. They usually appear in the late twenties or teens. When a person is old enough to acquire wisdom. Referred to as impacted and may cause pain or irritation. They are removed surgically

Wisdom teeth

Before permanent teeth, we have _______ its term is deciduous teeth. Usually erupt beginning about 6 months and they usually emerge upon the age of 2 and 1 half years. But when we are at the age of 6 and 13 years old, they are shedded by the body and replaced by permanent teeth

Baby or milk teeth or primary teeth

Tricel shaped and insert a sheering action used in biting. Have sharp edges for cutting food

Incisors

Cone shaped teeth used for tearing food

Canine teeth

Have two cusps or grinding surfaces

Premolars

Have a broad crown with a rounded cusps specialized for fine grinding of food

Molars

Have large, flat surfaces for crushing or grinding

Premolars and molars

Tooth anatomy (8)

• crown • neck • root • enamel • dentin • pulp cavity • periodontal ligament • cementum

Portion of tooth above the gum. Visible portion of teeth.

Crown

Serves as a boundary between the tooth and crown. Mixture or connection between the teeth and gums

Neck

Unseen. Is the embedded portion of tooth inside the bone.

Root

Majority of crown surface is covered by ______. Consists of 95-97% of inorganic calcium salts and it is the one that covers the crown

Enamel

Yellowish tissue. Composes the bulk of the tooth. Bone Like material interior to the enamel and cementum. Usually has odontoblast.

Dentin

Specialized cells that produce and maintain the dentin

Odontoblast

Surrounds the dentin. Contains connective tissues, blood, lymphatic vessels and nerves which is also known as pulp. Where odontoblast comes from

Pulp cavity

Holds the tooth in the tooth socket and exerts a cushioning effect

Periodontal ligament

One that cements or attaches the tooth to the periodontal ligament. Lines/covers the root of the tooth.

Cementum

Secrete saliva. Moistens the mouth and lubricates and protects the teeth. Moisten food and transform it into a mass called bolus

Salivary glands