Digestive System

digestive system

digestive system

Digestion (mechanical and chemical breakdown of food), Absorption of nutrients, Defecation (removal of undigested food).

alimentary canal

long hollow tube that the food passes through beginning at the mouth and ending at the rectum and anus.  It is also referred to as the gastrointestinal tract or (GI tract).

Stomach

Holds food, mechanical digestion by churning food and turning it into chyme, begins protein digestion and small amounts of fat digestion.

Pharynx

connects the mouth to the esophagus.

Esophagus

brings the food down to the stomach.

Large Intestines

 where most of the water is absorbed out of food.

Mouth

mechanical digestion from chewing, and also begins carbohydrate digestion with saliva and small amounts of fat also begin to chemically digest here.

Small Intestines

most of the chemical digestion occurs in the duodenum, almost all nutrient absorption occurs in the jejunum.

order that food goes through the above organs

Mouth, Pharynx, Esophagus, Stomach, Small intestine, large intestine

tongue

move food to different areas of the mouth so the teeth can chew and also forces the food into the pharynx and down the esophagus during swallowing.

bolus

ball of chewed food mixed with saliva in the mouth that gets swallowed.

chewing

Mastication

swallowing

Deglutition

peristalsis

This is the wavelike contractions in the smooth muscles in the walls of the alimentary canal that squeeze the food through the digestive tract.

lumen

hollow opening throughout the alimentary canal that the food passes through.

four layers of the walls of the digestive tract from inside to outside

Mucosa, Submucosa, Muscularis externa, Serosa

mesentery

the connective tissue that is attached to the serosa and the abdominal wall.  It holds the intestines in place in the abdominal cavity.

Gastric pits

 holes in the stomach where the chemicals are secreted out of.

Chyme

the paste food is turned into when mixed with the digestive juices and churned in the stomach.

Chief cells

Secrete pepsinogen into the stomach.

Parietal cells

Secrete hydrochloric acid into the stomach.

Enteroendocrine cells

Secrete gastrin and other hormones that help regulate digestive system.

3 sections of the small intestine in the order that food goes through them

Duodenum, Jejunum, Ilium

where the most chemical digestion occurs in the body

In the Duodenum of the small intestine

where the most nutrient absorption occurs in the body

In the Jejunum of the small intestine

 6 sections of the large intestine in the order that food goes through them

Cecum, Ascending colon, Transverse colon, Descending colon, Sigmoid colon, rectum

Pancreas

produces digestive enzymes for all major macromolecules, controls blood sugar by producing insulin and glucagon

Liver

Produces bile, filters toxins out of the blood, stores sugar as glycogen and releases it when signaled by pancreas

Gallbladder

Stores bile

Teeth

masticate (chew) food to begin mechanical digestion

Salivary glands

produce saliva to help begin chemical digestion

Amylase

chemically break down carbohydrates in the mouth

Pepsin

chemically break down protein in the stomach

Bile

produced by liver to help chemically break down fats

Pancreatic juice

combination of digestive enzymes produced by the pancreas to chemically break down carbohydrates, proteins and fats

HCl

In the stomach, Kills bacteria on food and activates pepsinogen by turning it into pepsin

Insulin

produced by the pancreas when blood sugar is too high, tells body cells to take in sugar out of the blood and use it

Thyroxine

controls the basal metabolic rate

Glucagon

produced by the pancreas when blood sugar is too low, tells the liver to convert glycogen into sugar and release it into the blood

What substance does the liver turn sugar into when it is being stored?

Glycogen

What is the function of villi?  In what organ are they located?

These are the fingerlike structures in the small intestine.  They increase the surface area of the small intestine to increase the amount of nutrients that can be absorbed.

Ingestion

intake of food into the mouth

Propulsion

movement of food through the digestive system.  Peristalsis is the slow wavelike contractions that move food along the alimentary canal.  Mass movements are the strong contractions that move food towards the end of the large intestine.

Mechanical digestion

the physical breakdown of food by the teeth and stomach

Chemical digestion

The chemical breakdown of macromolecules into their simpler subunits.

Absorption

Taking the nutrients out of the small intestine and into the blood

Defication

removal of the undigested remains of food

Carbohydrates

In the mouth and duodenum of the small intestine

Proteins

In the stomach and the duodenum of the small intestine

Lipids

Mainly in the duodenum of the small intestine (small amounts are digested in the mouth and stomach)

Calorie

The amount of energy it takes to raise 1 kg of water by 1^o C.  It is a measure of how much energy is in your food.

nutrient

Any substance obtained from food used to help maintain normal body functions, growth and repair

Carbohydrates

sugars, used for energy production

Lipids

fats, oils cholesterol.  Used for cell membranes, insulation, protection, energy storage and hormones

Proteins

used to build cells, enzymes and many other body materials

Vitamins

organic molecules used as coenzymes to help enzymes and other reations

Minerals

inorganic substances needed by the body for proper functioning

Water

many of the body processes require water to work

Metabolism

all the chemical reactions in the body to keep you alive and functioning

Catabolism

Breaking down molecules into smaller subunits

Anabolism

Building up larger molecules from smaller ones

cholesterol

Helps to produce cell membranes, hormones and vitamin D

LDL

bad lipoproteins, transports cholesterol to body cells

HDL

good lipoproteins, transports cholesterol to the liver

Liver

Stores extra sugar as glycogen, converts glycogen to sugar when pancreas releases glucagon due to low blood sugar

Pancreas

releases insulin when blood sugar is too high to tell body cells to take in extra sugar.  Releases glucagon when blood sugar is too low which tells the liver to convert glycogen to sugar and release it into the blood.

basal metabolic rate

amount of heat produced by the body when it is at rest.  Your minimum energy requirement to stay alive.

total metabolic rate

total amount of energy required to sustain whatever activity you are doing.

two heat promoting mechanisms

Vasoconstriction and Shivering

two heat loss mechanisms

Evaporation and Radiation

What happens to most of the energy we get from our food?

60% of it gets converted into heat and released from the body

Acid reflux

hydrochloric acid gets back through the cardioesophageal sphincter and comes back up the esophagus

Heartburn

the burning feeling caused from acid reflux

Ulcer

a hole in the mucus lining of the digestive system

Pancreatitis

inflammation of the pancreas.  Usually due to digestive enzymes being activated before leaving the pancreas and begin to digest the pancreas.

Hepatitis

Inflammation of the liver

Cirrhosis

hardening of the liver

Jaundice

skin and eyes turn yellow due to bilirubin building up in the blood.  A sign that the liver is not functioning properly.

Gallstones

bile sits in the gallbladder too long and begins to crystalize

Diarrhea

not enough water is absorbed by the large intestine

Constipation

too much water is absorbed by the large intestine

Hyperglycemia

high blood sugar

Hypoglycemia

low blood sugar

Hyperthyroidism

overactive thyroid increases BMR causing high metabolism and weight loss

Hypothyroidism

underactive thyroid decreases BMR causing low metabolism and weight gain

PKU

the body cannot properly break down and use the amino acid phenylalanine.  Can cause brain damage.

Appendicitis

inflammation of the appendix