Digestive System Test

Freaking Killing myself bc this class sucks and I want to die

Digestion

The breakdown of food into simpler compounds and their absorption

2 Types of Digestion

Physical or Mechanical

Chemical

Physical or Mechanical Digestion

The breakdown of food from big pieces into smaller pieces

Chemical Digestion

The breakdown of food into their simplest substance

Mucosa

Innermost Layer

Submucosa

Contains many blood vessels and nerve fibers

Muscular Layer

Has 2 Layers of Muscles

Serosa

Protects underlying tissue and secretes serous fluid

Incisors

Biting

Cuspids (canines)

Tearing

Bicuspids and Molars

Grinding

Mouth

Begins the physical digestion (chewing) of food

Mastication

Chewing of food begins physical digestion

Salivary Amylase

Salvatory glands release this which begins chemical digestion of carbohydrates

Pharnyx

Involved in the swallowing reflex

3 Parts of the Pharynx

Nasopharynx

Oropharynx

Laryngopharynx

3 Major Salivary Glands

Parotid

Sublingual

Submandibular

Salivary Glands

\-Secretes saliva

\-Moistens food which makes taste possible

\-Cleans the mouth

2 Types of Cells in Salivary Glands

Serous and Mucous

Serous Cells

Produces salivary amylase

Mucous Cells

Produces mucus (m)

Esophagus

\-Leads into the stomach

\-Begins the process of peristalsis

Peristalsis

Wave-like motion of muscles to move food

4 Parts of the Stomach

Cardiac Region

Fundic Region

Body

Pyloric Region

4 Types of Cells in Gastric Glands

Mucous Cells

Parietal Cells

Chief Cells

G-Cells

Parietal Cells

\-Produces HCl

\-Produces Intrinsic factor (helps absorb Vit. B12)

Chief Cells

Produce pepsinogen

G-Cells

Produce gastrin

Physical Digestion

\-Peristaltic waves pass over the stomach every 15-25 seconds

\-This wave action blends the food into a soupy substance called chyme

Chemical Digestion

\-Pepsinogen changes into active pepsin in the presence of HCl

\-Breaks proteins down into polypeptides

Gastric Absorption

Some water

Ions

Short fatty acids

Certain drugs (aspirin)

Alcohol

Regulation of Gastric Secretions

Cephalic Phase

Gastric Phase

Intestinal Phase

Cephalic Phase

When you see, smell, think about, or taste food, the brain tells the gastric glands to produce gastric juices

Gastric Phase

\-When food enters the stomach, it expands, gastrin is released

\-Gastrin causes the release of gastric juices from the gastric glands

Intestinal Phase

\-When chyme enters the small intestine, 2 hormones are produced by the intestinal glands, secretin & CCK

Secretin

Decreases gastric secretions

CCK

Keeps too much food from leaving the stomach

2 Types of Cells in the Pancreas

Islets of Langerhans and Pancreatic Cells

Islets of Langerhans

Produce insulin & glucagon

Pancreatic Cells

Secrete pancreatic juices

Pancreatic Juice

\-Is a basic solution to neutralize the chyme

Enzymes in Pancreatic Juice

\-Pancreatic Amylase

\-Pancreatic Lipase

\-Trypsin

\-Chymotrypsin

\-Carboxypeptidase

\-Pancreatic Nuclease

Pancreatic Amylase

Breaks down carbs

Pancreatic Lipase

Breaks down lipids

Trypsin, Chymotrypsin, and Carboxypeptidase

Breaks down proteins

Pancreatic Nuclease

Breaks down nucleic acids

Regulation of Pancreas

Secretin & CCK causes the release of pancreatic juices into the small intestine

Functions of the Liver

\-Carbohydrate metabolism

\-Lipid metabolism

\-Protein metabolism

\-Removes damaged RBC’s

\-Removes toxins

\-Makes bile

Structure of the Liver

\-2 Lobes

\-Lobes are divided into hepatic lobules

\-100,000-200,000

Bile

Made by hepatocytes

Function of Bile

\-Emulsifies fat

\-Breaks big fat globules into small fat globules

Regulation of Bile

\-Constantly made by liver cells

\-Nerve impulse can trigger bile production

Gallbladder

\-Stores excess bile from the liver

\-Releases bile when CCK is present

Structure of the Small Intestine

\-Mucosa forms finger-like projections called villi

\-Each villus contains absorptive cells that have microvilli on them

Goblet Cells

Produces Mucus

Lacteal

A lymph capillary that involves fatty acid absorption

Intestinal Glands

Secrete intestinal juices

Functions of Small Intestine

\-Segmentation

\-Completes chemical digestion of food

\-Absorbs 90% of all nutrients

Segmentation

Mixes chyme with digestive juices, peristalsis moves food through the small intestine

Carbohydrates

\-Pancreatic amylase breaks down polysaccharides

\-sucrase, lactase, & maltase made by the intestinal glands breaks down disaccharides into monosaccharides

Proteins

Aminopeptidase and dipeptidase made by the intestinal glands breaks down polypeptides into amino acids

Lipids

Intestinal lipase & pancreatic lipase splits the fatty acids from the glycerol

Nucleic Acids

Pancreatic nuclease and intestinal nuclease breaks down RNA & DNA into nucleotides

Functions of the Large Intestine

\-Absorption of water and electrolytes

\-Contain bacteria that changes waste into a semi-solid and produces some vitamin K

\-NO DIGESTION OCCURS IN THE LARGE INTESTINE

Feces

\-75% water

\-Bacteria

\-Mucus

\-Undigested Food

\-Bile

\-Bile Pigments

\-Cellulose (Fiber)

Nutrients

\-Carbohydrates

\-Lipids

\-Proteins

\-Vitamins

\-Minerals

\-Trace Elements (Metals)

Adequate Diet

Provides sufficient energy and nutrients to support optimal growth and to maintain and repair body tissue