digestive system

Order through which food passes in the alimentary canal

The digestive process, which includes ingestion, digestion, absorption, and excretion, as food moves from the mouth to the anus through various organs.

Structure that is continuous with the esophagus

is the stomach, where food begins to be broken down further through mechanical and chemical processes.

Layers that line the alimentary canal

The layers that line the alimentary canal include the mucosa/lumen, submucosa, muscularis externa (smooth muscle cells), and serosa (serous fluid producing cells)

the mucosa of the stomach produces what

protective layer of bicarbonate-rish alkaline mucus that clings to stomach mucosa and protects the stomach wall from being damaged

Gastric Production

refers to the secretion of gastric juices, including hydrochloric acid and digestive enzymes, essential for digestion.

some stomach cells produce what

intrinsic factor - a substance needed for the absorption of vitamin B12 from the small intestine.

The cheif cells produce what

digestive enzymes, primarily pepsinogen, which is activated to pepsin in the acidic environment of the stomach.

The parietal cells

produce corrosive hydrochloric acid and intrinsic factor, which makes the stomach contents acidic and activated enzymes

The endocrine cells produce what

local hormones such as gastrin that are important for digestion

Chyme enters the small intestine through…

pyloric sphincter

Pyloric Sphincter

a muscle that controls the release of chyme from the stomach into the small intestine. It prevents backflow and regulates the passage of food.

Protein Digestion

the process of breaking down proteins into amino acids through the action of enzymes, starting in the stomach and continuing in the small intestine.

Villi are what

projections of the mucosa that give it a velvety appearance and feel, within each is a rich capillary bed and modified lymphatic capillary called Lacteal

Location of the small intestine

is found between the stomach and the large intestine, comprised of three main sections: duodenum, jejunum, and ileum.

Organs that release secretions into the duodenum

include the pancreas, liver, and gallbladder. These organs contribute enzymes and bile for digestion.

Function of the duodenum

is to receive partially digested food from the stomach and neutralize stomach acid, preparing it for further digestion and nutrient absorption.

Overall function of the small intestine

is to digest food and absorb nutrients and water into the bloodstream, facilitating proper nutrition.

enzymes that are produced by the pancreas and then ducted into the duodenum through pancreatic ducts where they complete the chemical breakdown of foods in the small intestine

.

Bile is produced by what and enters the duodenum through that

produced by the liver

enters through the bile ducts

The pancreatic ducks and bile ducts joing at the duodenum to form what

the flask like hepatopancreatic ampulla

The bile and pancreatic juice travel through what to enter the duodenum together

duodenal papilla

Subdivisions of the large intestine

include the cecum, appendix, colon, rectum, and anal canal

Function of the large intestine

absorbs water and electrolytes, compacts waste, and prepares it for elimination from the body.

mastication

The process of chewing food to break it down into smaller particles for easier digestion.

Amylase

A digestive enzyme that breaks down carbohydrates into simpler sugars, primarily found in saliva and pancreatic fluid.

Number of permanent teeth

Adult humans typically have 32 permanent teeth.

Incisors

The sharp, flat teeth located at the front of the mouth, primarily used for cutting food.

The digestive system organ that is situated retroperitoneal

is the pancreas, which plays a crucial role in digestion by producing enzymes and hormones such as insulin.

Bile

A digestive fluid produced by the liver, stored in the gallbladder, and released into the small intestine to aid in the digestion and absorption of fats.

Bile leaves liver through what

common hepatic duct

gallbladder

thin-walled green sac that in a shallow fossa in the inferior of the liver and stores bile, releasing it into the small intestine when needed for fat digestion.

Chemical Digestion

The process by which food is broken down into simpler chemical compounds, typically through enzymatic action in the stomach and small intestine.

the only carbohydrates that our digestive system digests or breaksdown to simple sugars are…

sucrose, lactose, maltose, and starch because they are just two simple sugars linked together

Mechanical Digestion

The physical process of breaking down food into smaller pieces, which increases the surface area for enzymes to act upon. This process occurs primarily in the mouth and stomach.

Swallowing depends largely on the propulsive process called…

peristalsis, which involves coordinated muscle contractions that move food through the esophagus.

Segmentation helps do what

propel foodstuffs through the small intestine it normally moves food only back and forth across the internal wall of the organ

Carbohydrate digestion

involves the breakdown of carbs into simpler sugars through enzymatic action, primarily in the mouth and small intestine.

building blocks of proteins

are amino acids, which are linked together by peptide bonds to form proteins.

what is absorption

the transport of digested end products from the lumen on the GI tract to the blood or lymph.

For absorption to occur…

digested foods must enter the musical cells by active or passive transport processes, the small intestine is a major absorption site.

Digestion is primarily controlled by…

reflexes via the parasympathetic division of the autonomic nervous system.

example of chemical breakdown of food

is the process of enzymatic reactions that convert complex food molecules into simpler substances, such as the digestion of proteins into amino acids by proteases.

Starch Digestion

is the enzymatic breakdown of starch into simpler sugars, primarily glucose, by enzymes like amylase in the mouth and small intestine.

Degulation or swallowing is what

a complex process that involves the coordinated activity of the tounge, soft palate, pharynx, and esophagus to move food from the mouth to the esophagus, facilitating the first stage of digestion.

Esophagus

is a muscular tube that connects the throat (pharynx) with the stomach, acting as a conduit for food and liquid during swallowing.

pepsin

the active protein digesting enzyme

rennin

second protein-digesting enzyme produced by the stomach, produced in large amounts in infants but not believed to be produced in adults.

enterogastric reflex

this occurs when the duodenum is filled with chyme and its walls are stretch, puts a break on gastric activity

The length of time for chyme in the small intestine

is known as the intestinal transit time, which influences nutrient absorption and digestion efficiency.

Pancreatic juice contains what?

enzymes that along with brish border enzymes complete the digestion of starch, they also contain a rich supply of bicarbonate which makes it very basic (ph of about 8)

When chyme enters the small intestine the mucosa cells produce what hormones

cholecystokinin and secretin which both influence the release of pancreatic juice and bile.

What does the large intestine absorb

water, electrolytes, and vitamins, primarily B vitamins and vitamin K, while forming and storing feces.

kilocalories

a measure of energy derived from food, indicating the amount of energy the body can obtain from consuming that food.

mineral rich food

that provides essential vitamins and minerals important for various bodily functions and overall health. vegetables, legumes, milk, some meats

catabolism

substances are broken down to simpler substances

anabolism

larger molecules or structures are built from smaller ones

cellular respiration

the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

glycogenesis

the process of converting glucose into glycogen for storage. “glycogn formation”

glycogenolysis

the breakdown of glycogen into glucose when energy is needed. “glycogen splitting”

gluconeogenesis

the process of synthesizing glucose from non-carbohydrate sources, typically during periods of fasting or low carbohydrate intake. “formation of new sugar”

ketoacidosis

a condition resulting from high levels of ketones in the blood, often due to uncontrolled diabetes, leading to metabolic acidosis.

role of the liver in digestion

manufacture of bile, detoxify drugs and alcohol, degrade hormones, and make cholesterol, blood proteins

hepatic portal circultion

the pathway through which blood from the gastrointestinal tract and spleen is transported to the liver. This circulation allows for the metabolism of nutrients and detoxification.

Cholesterol

lipid, not used in energy fuel, serves as structural basis of steroid hormones and vitamin D