The Digestive System

What substance covers the tooth root

the enamel, which is the shell that covers the visible part of the tooth. the cementum, which covers the roots. the dentin, a bone-like substance which makes up most of the tooth. the pulp and pulp cavity, which contains the blood vessels

Large intestine anatomy and histology

the last part of the digestive system in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass the useless waste material from the body. The large intestine consists of the cecum, colon, rectum, and anal canal

Serosa

serous membrane and a connective tissue layer that binds together structures rather than reduces friction between them

Digestion

starts here as soon as you take the first bite of a meal. Chewing breaks the food into pieces that are more easily digested, while saliva mixes with food to begin the process of breaking it down into a form your body can absorb and use

Mesentary

supportive membrane surrounding internal organs and attaching to the body wall

Chief cells of gastric glands

secrete pepsinogen

Mucous neck cells of gastric glands

secretes acid fluid containing mucin

Boundaries of the oral cavity

Anteriorly - Vermilion border A: Posteriorly - Posterior border of hard palate, intersection of retromolar trigone and anterior pillar, circumvallate line of the tongue

normal number of deciduous teeth

20

pharyngeal-esophageal phase

3 actions block food and drink from reentering mouth or nasal cavity or larynx

normal number of permanent teeth

32

Describe gastric movements and stomach emptying and how they are regulated

A hormone called gastric inhibitory peptide is secreted by the small intestine to slow down the peristaltic movements of the intestine to allow fatty foods more time to be digested and absorbed. Understanding the hormonal control of the digestive system is an important area of ongoing research

Submucosa

A layer of the human digestive system that contains nerves, blood vessels, and lymph nodes

What and where is pulp

Accessory canals are pathways from the radicular, extending laterally through the dentin to the periodontal tissue seen especially in the apical third of the root. Accessory canals are also called lateral canals because they are usually located on the lateral surface of the roots of the teeth

Transport of fats and lipids

Although the term fat is often used interchangeably with lipids, fats are only a subgroup of lipids, namely triglycerides. Lipids are also made up of phospholipids and sterols, such as cholesterol. Because lipids are insoluble in water, they require a special transport vehicle to move through the body's bloodstream

what are the effects of aging on digestive system activity?

Because the digestive system has a lot of reserve built into it, aging has relatively little effect on its function compared to its effects on other organ systems. Nonetheless, aging is a factor in several digestive system disorders. In particular, older adults are more likely to develop diverticulosis and to experience digestive tract disorders (for example, constipation) as a side effect of taking certain drugs. Stomach: With age, the stomach lining's capacity to resist damage decreases, which in turn may increase the risk of peptic ulcer disease, especially in people who use aspirin and other nonsteroidal anti-inflammatory drugs Constipation becomes more common. This may be due partly to a slight slowing in the movement of contents through the large intestine and a modest decrease in the contractions of the rectum when filled with stool.

Name 1 inflammatory condition of the digestive system common to adolescents, 2 common in middle age and 1 common in old age

Celiac inflammatory bowel disease Crones disease Diverticulitis

What substance makes up the bulk of the tooth

Dentin is the hard substance that makes up the bulk of the tooth structure. On the crown it is covered by enamel. Dentin is produced by the tissue that lines the pulp canal, and continues as long as the pulp is living

Describe structure of a tooth

Each tooth consists of two main portions called the crown and the root. The crown is the portion above the gum and is covered by glossy white enamel. Beneath the enamel is the bulk of the tooth, which is made up of dentin. Dentin surrounds the central cavity, which houses the blood vessels, nerves and connective tissue. The root is enclosed by cementum, which is surrounded by the periodontal ligament. The region where the crown and root meet is called the neck.

What substances covers the tooth crown

Enamel covers the crown; cementum, the root. c)Dentin makes up the bulk of the tooth

Secretions and movements of small intestine

It is a reflex that inhibits gastric motility and the secretion of gastric acid, essentially putting the brakes on the emptying of the stomach so digestion in the small intestine has time to catch up. ... It is defined as a localized contraction of circular smooth muscles that constrict the intestine into segments.

Describe general histology of the digestive tract

It lines the lumen. The mucosa consists of epithelium, an underlying loose connective tissue layer called [glossary term:] lamina propria, and a thin layer of smooth muscle called the muscularis mucosa. In certain regions, the mucosa develops folds that increase the surface area.

There is a gut-brain called enteric nervous system, is it part of the parasympathetic or sympathetic nervous system? Explain.

It normally communicates with the central nervous system (CNS) through the parasympathetic (e.g., via the vagus nerve) and sympathetic (e.g., via the prevertebral ganglia) nervous systems. However, vertebrate studies show that when the vagus nerve is severed, the enteric nervous system continues to function

Discuss water movement into and out of the digestive tract

Movement of water is often driven by osmosis: water moves from regions of low solute concentration to regions of higher solute concentration. For example, the digestive tract of many animals is lined with a single layer of epithilial cells, tightly connected cells that play a role in absorption and digestion

regulation of large intestine

Nervous control of secretion is influenced by peripheral and central nerves. They are tonically inhibited by the enteric nervous system, in particular by the submucous plexus, to maximally absorb fluid and electrolytes

List major functions of digestive system

Secretion of fluids and digestive enzymes. Mixing and movement of food and wastes through the body. Digestion of food into smaller pieces. Absorption of nutrients.

Parts of the large intestine

The ascending colon including the cecum and appendix. The transverse colon including the colic flexures and transverse mesocolon. The descending colon. The sigmoid colon - the s-shaped region of the large intestine. The rectum

List characteristics of small intestine that account for its large surface area

The inner surface of the jejunum, its mucous membrane, is covered in projections called villi, which increase the surface area of tissue available to absorb nutrients from the gut contents. The epithelial cells which line these villi possess even larger numbers of microvilli

Mucosa

The innermost layer of the human digestive tract; in some parts of the digestive system, it contains mucus-secreting cells and glands that secrete digestive enzymes

Liver

The liver has three main components: hepatocytes, bile canaliculi, and hepatic sinusoids. ... This duct then joins with the cystic duct from the gallbladder, forming the common bile duct through which bile flows into the small intestine.

Major functions and Regulation of Liver

The liver's main job is to filter the blood coming from the digestive tract, before passing it to the rest of the body. The liver also detoxifies chemicals and metabolizes drugs. As it does so, the liver secretes bile that ends up back in the intestines. most chemical levels in the blood and excretes a product called bile. ... Production of bile, which helps carry away waste and break down fats in the small intestine during digestion. Production of certain proteins for blood plasma

Transport of Carbohydrates

The metabolism is the process of getting the carbohydrates in the foods we eat into the right format to provide fuel to our body's cells. This process involves digestion, absorption and transportation. Energy or fuel from our food is used for cell growth, repair, and normal cell functioning

Describe mastication and swallowing

The pharynx is a route for breathing and feeding but is used in different ways. The pharyngeal cavity consists of the muscles of the soft palate, tongue, epiglottis, and pharyngeal walls, and its shape is altered dynamically for breathing, eating or vocalization

Describe Major salivary glands

The salivary glands are exocrine glands in and around the oral cavity that secrete their salivary contents into the mouth. The parotid gland is the only gland that secretes purely serous saliva, while the sublingual gland and minor salivary glands secrete mainly mucous saliva

Six functional activities of digestive system

The six involved in this process are ingestion, motility, mechanical digestion, chemical digestion, absorption, and defecation

Stomach secretions

The stomach produces and secretes several important substances to control the digestion of food. Each of these substances is produced by exocrine or endocrine cells found in the mucosa. The main exocrine product of the stomach is gastric juice — a mixture of mucus, hydrochloric acid, and digestive enzymes

Minerals

There are approximately 4000 different minerals, and each of those minerals has a unique set of physical properties. These include: color, streak, hardness, luster, diaphaneity, specific gravity, cleavage, fracture, magnetism, solubility, and many more

Pancreas

They have flattened cuboidal epithelium that extends up into the lumen of the acinus to form what are called centroacinar cells. Intralobular ducts have a classical cuboidal epithelium and, as the name implies, are seen within lobules. They receive secretions from intercalated ducts

Buccal phase

Tongue collects food compacts it and pushes it back to the oropharynx

Enteroendocrine cells of gastric glands

secrete gastrin into bloodstream to stimulate gastric secretions and muscle contractions

outline anatomical and physiological characteristics of the stomach

When it's empty the mucosa has a ridged appearance. These ridges (rugae) flatten out as the stomach fills with food. The next layer that covers the mucosa is the submucosa. It is made up of connective tissue that contains larger blood and lymph vessels, nerve cells and fibres

Regulation of gastric phase of gastric secretion

a period in which swallowed food and semi-digested protein ( peptides and amino acids ) activate gastric activity. About two-thirds of gastric secretion occurs during this phase. Ingested food stimulates gastric activity in two ways: by stretching the stomach and by raising the pH of its contents

Muscularis Externa

a region of muscle in many organs in the vertebrate body, adjacent to the submucosa. It is responsible for gut movement such as peristalsis.

Regulation of intestinal phase of gastric secretion

a stage in which the duodenum responds to arriving chyme and moderates gastric activity through hormones and nervous reflexes. The duodenum initially enhances gastric secretion, but soon inhibits it

Major Functions of Large intestine

absorb water from the remaining indigestible food matter and transmit the useless waste material from the body

Major functions and Regulation of Pancreas

an organ located in the abdomen. It plays an essential role in converting the food we eat into fuel for the body's cells. The pancreas has two main functions: an exocrine function that helps in digestion and an endocrine function that regulates blood sugar. Enzymes, or digestive juices, are secreted into the small intestine. There, it continues breaking down food that has left the stomach. It also produces the hormone insulin and secretes it into the bloodstream, where it regulates the body's glucose or sugar level

vitamns

are nutrients your body needs to develop and function properly. There are 13 essential: A, D, E, and K, which are fat-soluble, and C and the B-complex group, which are water-soluble. Each has a distinct role in keeping you healthy

Proteins

are polymers of amino acids, formed by long chains of amino acids joined together by peptide bonds. These bonds are formed by condensation reactions which allow two single amino acid molecules to join together forming a dipeptide molecule and water

Parietal cells in gastric glands

are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the cardia of the stomach. Function: Gastric acid, intrinsic factor secretion Location: Stomach

Absorption

assimilating substances into cells or across the tissues and organs through diffusion or osmosis, as in absorption of nutrients by the digestive system, and drugs into the bloodstream. Supplement, in general sense, is the act or process of absorbing or assimilating

activation of pancreatic enzymes in the small intestine in a good example of the wisdom of the body, how so?

because it neutralizes the alkaline blood draining out of the stomach with the acidic blood from pancreas, so when it leaves to go to the heart it is neutral

explain why fatty stools result from the absence of bile or pancreatic juice

bile's role is to emulsify fats, or break them down. the pancreatic juice contains enzymes that also break down food stuff, without them fat would not get broken down and would end up being a waste product

two phases of swallowing

deglutition - swallowing, has 2 phases the buccal phase occurs in the mouth and is voluntary the tongue forces the bolus into the oropharynx the pharyngeal-esophageal phase of swallowing is controlled by the swallowing center in the brain stem and is involuntary. food enters pharynx, all routes except to digestion are blocked off, the tongue blocks off the mouth, the soft palet rises to close off the nasopharynx, the larynx rises so the epiglottis covers the opening to the respiratory passageways. solid food passes from oropharynx to stomach after food enters stomach the esophageal sphincter closes to prevent regurgitation.

gastric glands

exocrine glands in the stomach wall that secrete gastric juice into the stomach

Mesocolon

extension of the mesentery that anchors the colon to the posterior abdominal wall

Regulation of cephalic phase of gastric secretion

occurs before food enters the stomach, especially while it is being eaten. It results from the sight, smell, thought, or taste of food; and the greater the appetite, the more intense is the stimulation

greater omentum

part of the peritoneum attached to the stomach and to the colon and covering the intestines

parotid gland

salivary gland within the cheek, just anterior to the ear

indicate the function of the kupffer cells and the hepatocytes of the liver

kupffer cells - remove debris such as bacteria and worn out blood cells from the blood as it flows past. They are star shaped parts of the sinusoid walls of the liver. Hepatpcytes - a 'plate' of liver cells organized like garden bricks. they produce bile and can process blood borne nutrients in many ways they store glucose as glycogen, they they store fat soluble vitamins and they play a role in detoxification by by ridding blood of ammonia by converting it to urea

exocrine glands

secrete chemical substances into ducts that lead either to other organs or out of the body

Name the major layers of alimentary canal wall

the mucosa, submucosa, musclaris externa, and serosa

what is the relationship between the cystic, common hepatic, bile, and pancreatic ducts? what is the point of fusion of the bile and pancreatic ducts called?

they all join together and empty into the duodenum hepatopancreatic ampulla and sphincter

sublingual gland

under the tongue

Oral cavity why do you suppose its mucosa is stratified squamous epithelium

which may or may not be keratinized, and an underlying connective tissue layer, the lamina propria. The surface is kept moist with mucus produced by the major and numerous minor salivary glands