G11 Biology Unit 2 Systems

Digestive tract

a series of hollow organs joined in a long, twisting tube from the mouth to the anus

Gastrovascular Cavity

a simple, sac-like digestive cavity that has only one opening through which food is taken in and wastes are expelled

Gastrointestinal Tract (GI tract)

the passageway or tube that extends from the mouth to the anus and in which the process of digestion takes place

Alimentary Canal

the whole passage along which food passes through the body from mouth to anus. It includes the esophagus, stomach, and intestines.

Mouth

the natural opening through which food passes into the body of an animal and which in vertebrates is typically bounded externally by the lips and internally by the pharynx and encloses the tongue, gums, and teeth.

Esophagus

an organ consisting of a muscular tube that passes food from the pharynx to the stomach

Stomach

The stomach is a muscular organ located on the left side of the upper abdomen. The stomach receives food from the esophagus.

Small Intestine

The part of the intestine that runs between the stomach and the large intestine; the duodenum, jejunum, and ileum collectively.

Large Intestine (Colon)

The long, tube-like organ that is connected to the small intestine at one end and the anus at the other. The large intestine has four parts

Rectum

The final section of the large intestine, terminating at the anus. The lower 20 cm of the large intestine, generally referred to as the lower bowel, where feces are stored

Anus

The opening at the end of the alimentary canal through which solid waste matter leaves the body. The opening at the lower end of the large intestine through which digestive wastes are eliminated from the body

Digestion

The process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body and absorbed by the bloodstream.

Ingestion

The process of taking food, drink, or another substance into the body by swallowing or absorbing it.

Tongue

a muscular organ in the mouth that aids in chewing, speaking and breathing

Salivary Glands

produce saliva (spit) and empty it into your mouth through ducts, or small openings. They lubricate your mouth and throat, aid in swallowing and digestion, and help shield your teeth from cavity-causing bacteria.

Mechanical Digestion

physically breaking down food substances into smaller particles to more efficiently undergo chemical digestion. Mechanical digestion begins in your mouth with chewing, then moves to churning in the stomach and segmentation in the small intestine. Peristalsis is also part of mechanical digestion

Chemical Digestion

the process where complex molecules like proteins, fats, and carbohydrates are broken down into smaller pieces that your body can use. It requires special proteins called enzymes.

Absorption

The process of taking nutrients from the digestive system into the blood so they can be used in the body.

Egestion

Egestion is the act of excreting unusable or undigested material from a cell, as in the case of single-celled organisms, or from the digestive tract of multicellular animals. The removal of waste food materials from the body

Oral Cavity

mouth, in human anatomy, orifice through which food and air enter the body

Enzyme

any chemical produced by cells that facilitates biochemical reactions in the body, such as those involved in digestion and metabolism; all enzymes are proteins

Amylase

an enzyme that breaks down complex carbohydrates

Mucus

a protective secretion produced by the epithelial cells that form the mucous membrane

Peristalsis

the rhythmic, involuntary wave-like contractions of the smooth muscles of the gastrointestinal tract

Sphincter

the circular muscle that contracts to close an opening in the body

Chyme

a semi-liquid mixture of food and gastric juice

Gastrin

a hormone that stimulates the release of hydrochloric acid and pepsinogen in the stomach

Ulcer

a lesion or open sore on the epithelium of an organ

Saliva

a thick, colorless, fluid that is constantly present in the mouth of humans and other vertebrates. It is composed of water, mucus, proteins, mineral salts, and amylase. As saliva circulates in the mouth cavity it picks up food debris, bacterial cells, and white blood cells.

Salivary amylase

is a glucose-polymer cleavage enzyme that is produced by the salivary glands. It comprises a small portion of the total amylase excreted, which is mostly made by the pancreas.

Carbohydrates

are sugar molecules. Along with proteins and fats, carbohydrates are one of three main nutrients found in foods and drinks. Your body breaks down carbohydrates into glucose.

Glucose

(blood sugar) is the main source of energy for your body's cells, tissues, and organs.

Bolus

food that has been chewed and mixed in the mouth with saliva

Pharynx

The hollow tube inside the neck that starts behind the nose and ends at the top of the trachea (windpipe) and esophagus (the tube that goes to the stomach).

Epiglottis

The flap that covers the trachea during swallowing so that food does not enter the lungs.

Cardiac Sphincter

The somewhat thickened muscular ring surrounding the opening between the esophagus and the stomach.

Pyloric Sphincter

muscular valve that opens to allow food to pass from the stomach to the top of the small intestine.

Hydrochloric Acid

Stomach acid

Pepsin

a protein-digesting enzyme produced in the stomach

Pepsinogen

A substance made by cells in the stomach. Acid in the stomach changes pepsinogen to pepsin, which breaks down proteins in food during digestion.

Villi

Tiny hair-like projections that line the inside of the small intestine. They contain blood vessels and help absorb nutrients.

Microvilli

a microscopic projection of the cell membrane of certain types of epithelial cells; greatly increases the surface area of the cell

Lumen

The cavity or channel within a tube or tubular organ such as a blood vessel or the intestine.

Duodenum

The first part of the small intestine. It connects to the stomach. The duodenum helps to further digest food coming from the stomach. It absorbs nutrients (vitamins, minerals, carbohydrates, fats, proteins) and water from food so they can be used by the body.

Jejunum

The middle part of the small intestine. It is between the duodenum (first part of the small intestine) and the ileum (last part of the small intestine). The jejunum helps to further digest food coming from the stomach.

Ileum

The last part of the small intestine. It connects to the cecum (first part of the large intestine). The ileum helps to further digest food coming from the stomach and other parts of the small intestine.

Caecum

A pouch that forms the first part of the large intestine. It connects the small intestine to the colon, which is part of the large intestine. A blind pouch at the upper end of the large intestine

Colon

The long, tube-like organ that is connected to the small intestine at one end and the anus at the other. The longest part of the large intestine

Ascending colon

part of the colon located between the cecum and the transverse colon.

Transverse colon

the longest and most mobile part of the colon. It runs from the right to the left of the abdomen and connects the end of the ascending colon to the start of the descending colon.

Descending colon

the part of the colon from the splenic flexure to the beginning of the sigmoid colon.

Sigmoid colon

The S-shaped section of the colon that connects to the rectum.

Appendix

A small, fingerlike pouch that sticks out from the cecum (the first part of the large intestine near the end of the small intestine).

Lymphatic System

The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases.

Appendicitis

Painful medical condition in which the appendix becomes inflamed and filled with pus, a fluid made up of dead cells and inflammatory tissue that often results from an infection.

Lacteal

a lymphatic vessel within a villus, through which digested fats enter the circulatory system

Secretin

a hormone secreted by the duodenum that stimulates pancreatic and bile secretions

Trypsin

a protein-digesting enzyme produced from trypsinogen

Enterokinase

an enzyme of the small intestine that converts inactive trypsinogen into trypsin

Lipase

an enzyme that digests lipids

Bile

a substance that emulsifies fats for faster breakdown by lipases; produced by the liver

passive transport the movement of materials across a cell membrane without any expenditure of the cell’s energy

Concentration Gradient

the difference in the number of molecules or ions of a substance in a given volume between adjoining areas

Facilitated Diffusion

the diffusion of molecules across a cell membrane via a transport protein

Active Transport

the transportation of materials through a cell membrane using energy from the cell

Feces

the undigested material that is eliminated as waste from the body

Endoscopy

any medical procedure that uses an endoscope to look inside the body

Pancreas

A glandular organ located in the abdomen. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines, and other organs.

Liver

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

Gallbladder

The pear-shaped organ found below the liver. Bile is concentrated and stored in the gallbladder.

Duct System

A passage with well defined walls, especially a tube for the passage of excretions or secretions

Duct

a bodily tube or vessel especially when carrying the secretion of a gland

Insulin

A hormone made by the islet cells of the pancreas. Insulin controls the amount of sugar in the blood by moving it into the cells, where it can be used by the body for energy.

Metabolism

The chemical changes that take place in a cell or an organism. These changes make energy and the materials cells and organisms need to grow, reproduce, and stay healthy. Also helps get rid of toxic substances.

Cholesterol

A waxy, fat-like substance made in the liver, and found in the blood and in all cells of the body. Cholesterol is important for good health and is needed for making cell walls, tissues, hormones, vitamin D, and bile acid.

Nausea

the feelings associated with having the urge to vomit

Emesis

the expulsion of stomach contents through the esophagus and the mouth; also known as vomiting

Diarrhea

Loose or watery feces. The condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss.

Constipation

A condition in which stool becomes hard, dry, and difficult to pass, and bowel movements don't happen very often. Other symptoms may include painful bowel movements, and feeling bloated, uncomfortable, and sluggish.

Gastroesophageal Reflux Disease (GERD)

Occurs when stomach acid repeatedly flows back into the tube connecting your mouth and stomach (esophagus). This backwash (acid reflux) can irritate the lining of your esophagus.

Ulcer

A break on the skin, in the lining of an organ, or on the surface of a tissue. An ulcer forms when the surface cells become inflamed, die, and are shed. Ulcers may be linked to cancer and other diseases.

Inflammatory Bowel Disease (IBD)

Characterized by chronic inflammation of the intestinal tract associated with an imbalance of the intestinal microbiota. Crohn's disease (CD) and ulcerative colitis (UC) are the most widely known types of IBD.

Aerobic Cellular Respiration

the series of chemical reactions that occur in the cell that provide energy and consume oxygen

Gas Exchange

the processes whereby the body cells obtain oxygen and get rid of carbon dioxide

Phosphorylation

the addition of a phosphate group to a molecule; in aerobic cellular respiration the phosphate group is added to ADP, creating the ATP molecule in which energy is stored

Ventilation

the process in more complex organisms that ensures a flow of oxygen rich air to the lungs

Trachea

the tube leading from the mouth toward the lungs

Bronchus

one of the two main branches of the trachea that lead toward the lungs

Bronchiole

a tiny branch of a bronchus that connects to a cluster of alveoli

Alveolus

a tiny sac at the end of a bronchiole that forms the respiratory membrane

Diaphragm

a large sheet of muscle located beneath the lungs that is the primary muscle in breathing

External Intercostal Muscle

a muscle that raises the rib cage, decreasing pressure inside the chest cavity

Internal Intercostal Muscle

a muscle that pulls the rib cage downward, increasing pressure inside the chest cavity

Pleural Membrane

a thin layer of connective tissue that covers the outer surface of the lungs and lines the thoracic cavity

Pneumothorax

a collapsed lung caused by the introduction of air between the pleural membranes

Total Lung Capacity

the maximum volume of air that can be inhaled during a single breath

Tidal Volume

the volume of air inhaled or exhaled during a normal, involuntary breath Inspiratory Reserve Volume

Expiratory Reserve Volume the volume of air that can be forcibly exhaled after a normal exhalation

Residual Volume

the volume of air remaining in the lungs after a forced exhalation vital capacity the maximum amount of air that can be inhaled or exhaled

VO2

an estimated or measured value representing the rate at which oxygen is used in the body, measured in milliliters per kilogram per minute