Digestive system 1

What is the digestive system

A group of organs that work together to break down food, absorb nutrients, and eliminate waste from the body

What are the organs of the digestive system

Mouth, Esophagus, Stomach, Small Intestine, Large Intestine, Rectum, and Anus

What does the mouth do?

Begins the process of digestion by chewing and mixing food with saliva

What does the esophagus do?

Connects the mouth to the stomach, allowing food to pass through

What does the stomach do?

Stores and mixes food with digestive juices to break it down further

what does the Small Intestine do?

Absorb nutrients from the digested food into the blood stream

What does the large intestine do?

Absorbs water and electrolytes and forms feces

what does the rectum do?

Stores feces before elimination

what does the anus do?

The opening through which feces are expelled from the body

What are the accessory organs

salivary glands, Liver, Gallbladder, Pancreas, teeth, tongue,

What does the Salivary glands do?

Produces saliva that aids in food digestion

What does the liver do?

Produces bile, which helps break down fats and detoxifies harmful substances

What does the pancreas do?

produces digestive enzymes and releases them into the small intestine

_______ is the process of taking in food through the mouth

Ingestion

______ is the process of breaking down food into smaller molecules through mechanical and chemical processes

digestion

_____ is the process of absorbing nutrients into the bloodstream through the walls of the small intestine

absorption

______ is the process of removing indigested waste material from the body

Elimination

The digestive system prepares ________ for absorption and utilization by the body.

nutrients

Mechanical digestion

The process of breaking down food into smaller pieces by chewing and grinding in the mouth and by the churning and mixing actions of the stomach.

Chemical digestion

Process in which large food molecules are broken down into smaller molecules by enzymes in the digestive system to facilitate absorption

Enzymes involved in digestion:

1. ____________: Breaks down carbohydrates into simple sugars.

2. ____________: Breaks down proteins into amino acids.

3. ____________: Breaks down fats into fatty acids and glycerol.

1. Amylase

2. Proteases

3. Lipases

______ aids in maintaining a healthy balance in the digestive system

Microorganisms

______ bacteria helps in the breakdown of certain indigestible carbohydrate

Gut

The Digestive system is also called the ________, _______________, ____________, or ___

Digestive tract, gastrointestinal tract, Alimentary canal, or gut

Requirements for _____ and ______ depend on the diet of the animal

Digestion and Absorption

__________ animals have simple, single stomach

Mono gastric

____ ________ have multiple mixing and fermentation compartments in addition to the stomach

Foregut Fermenters (ruminants)

_______ fermenters have enlarged cecum and colon used for fermentation

hindgut

______ plant eating animals

Herbivores

What are three examples of herbivores

Cattle, Sheep, Goat

______ are meat-eating animals

Carnivores

What are examples carnivores

Cats and dogs

______ are animals that eat anything, including plants and flesh

omnivores

What are the 5 functions of digestive system

Prehension, Mastication, Digestion, Absorption, Elimination

Prehension is the process of _____ food with the lips or teeth

grasping

Mastication is the ________ grinding and breaking down of food

Mechanical

Mucosa is the lining of what?

GI Tract

What are the three parts of the mucosa

Epithelium, Lamina Propria (connective tissue), and muscularis mucosae

Submucosa is __________ _______________ tissue

Dense connective

What is another name for the muscle layer

muscularis externa

What is the muscle layer to the submucosa

External

The muscle layer consists of what kinds of layers?

Circular and longitudinal muscle layer

The muscle layer is stimulated primarily by _____

Stretch

Serosa is the ______ layer and is thin, ____ _______ tissue

Outermost, tough connective

What are the cell shape classification for epithelial tissue

Squamous (flat)

Cuboidal

columnar

Name the 2 numbers of layers of cells

Simple and stratified

What are the characteristics of a stratified squamous epithelium

multilayered, thick, and tough

Where can you find stratified squamous epithelium

lining the mouth, esophagus, and anus

The simple columnar epithelium runs from the ____ of the esophagus and stomach through the _______ to the junction of the rectum and anus

junction; intestines

Smooth muscle is __________ muscle

Involuntary

Smooth Muscle is present in the wall of……. 5 answers

Caudal section of esophagus, stomach, small intestine, large intestine, and internal anal sphincter

Smooth muscle is primarily stimulated by ______

stretch

Smooth muscle is arranged in either _________ or _______ layers

Circular (inner), Longitudinal (outer) layer

Contraction of ________ _______ fibers narrows the tract

Circular Muscle

Contraction of ________ _______ fibers Shortens the tract

Longitudinal Muscle

striated muscle is a _______ muscle

Voluntary

Striated muscle can be found in…….

Mouth, Pharynx, Cranial portion of esophagus, and external anal sphincter

The presence of striated muscle allow the voluntary control of……

1. chewing

2. mixing saliva w/ food

3. Initiation of swallowing

4. initiation of defecation

What nervous system is unique to the digestive system?

Enteric nervous system

What are the 2 distinct neuronal circuits of sensory and motor neurons that are linked by interneurons

1. Submucosal plexus ( Meissner’s plexus)

2. Myenteric plexus (Auerbach’s plexus

The ______ _________ _________ is located entirely in the walls of the digestive tract

Enteric Nervous System

The enteric nervous system controls _______ and ________ activities of the gut

Motility and secretory

What are 3 main hormones in the gastrointestinal system

1. Gastrin

2. Cholecystokinin

3. secretin

What hormone causes gastric acid secretion

Gastrin

What hormone increases the enzyme secretion from the pancreas

Cholecystokinin

What hormone causes bicarbonate and water secretion from the pancreas and bile ducts

Secretin

what hormone enhances proliferation of cells in the stomach walls

Gastrin

What hormone stimulates gall bladder emptying

Cholecystokinin

What are the stimuli for secretion with the gastrin hormone

Vagus nerve, stretch, amino acids & peptides in stomach contents

What type of cells are the source for gastrin

G cells

Where would you find the gastrin hormone

Stomach and Duodenum

What type of cell is the source of the cholecystokinin hormone

I cells

You can find the cholecystokinin hormone in the __________

duodenum

The stimuli for secretion of the cholecystokinin hormone

Monoglycerides, fatty acids, amino acids on the duodenum

What cell type is the source for the secretin hormone

S cells

What is the stimuli for secretion for the secretin hormone

Acidic pH of contents of the duodenum

What are the three main salivary glands

Parotid, mandibular, and sublingual

What do salivary glands produce

Saliva

what species produces the most saliva

Swine

What are the 6 things saliva contains

1. water

2. proteins ( lysozyme)

3. electrolytes

4. antibodies

5. bicarbonate

6. enzymes (amylase)

Lysozymes and antibodies control _____ population

Microbe

______ is saliva digests carbohydrates in pigs, rats, and humans

Amylase

autonomic nervous system controls _____ in the digestive system

glands

What are the two types of systems that related to the control of salivation

Parasympathetic and sympathetic

Parasympathetic stimulation ______ salvation

increase

Sympathetic stimulation ______ salvation

decreases

______ of eating can cause the parasympathetic stimulation of the salivary glands

Anticipation

Inhibitors of the parasympathetic nervous system such as ______ produces dry mouth

atropine

The entrance of the esophagus from the pharynx is surrounded by skeletal muscle called _____ _________ __________ (UES)

Upper esophageal sphincter

The entrance of esophagus into stomach is surrounded by thick smooth muscle called ____ ________ __________ (LES)

Lower esophageal Sphincter

______ is the opening from the esophagus

cardia

What is the Distensible blind punch; expands as more food enters the stomach

Fundus

What is the Distensible middle part of the stomach

Body AKA corpus

The _______ ______ grinds food

Pyloric antrum

the ______ is a muscular sphincter

Pylorus

What does the pylorus do?

1. Regulates the movement of chyme from the stomach into the duodenum

2. Prevents backflow of duodenal contents into the stomach

In dogs, horses and ruminants the ____ ______ is present throughout the entire length of the esophagus

skeletal muscle

In Cats and Primates: middle to _____ sections of esophagus contains only _____ _______

distal; smooth muscle

secretions of glands in the wall of esophagus _______ the mucosa

Lubricates

What is the enzyme found in the saliva of omnivores

Amylase