Exam 4-The DIgestive System

Biology 341 with Garver at San Diego State University

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By: Alejandra Lopez
Created: 2010-11-30
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Gastrointestinal (Digestive) Tract

Oral Cavity ⇒ pharynx⇒ esophagus⇒ stomach⇒ small intestines⇒ large intestines⇒ rectum

What is the difference between the Alimentary Canal / Gastrointestinal tract and the accessory organs?

a. Alimentary Canal (aka Gastrointestinal Tract - GI Tract)

Oral Cavity ⇒ pharynx⇒ esophagus⇒ stomach⇒ small intestines⇒ large intestines⇒ rectum

b. Accessory Structures

Teeth, Salivary Glands, liver, gall bladder, pancreas

Where to the accessory organs contribute to the GI tract?

-Teeth/Salivary Gland->Oral Cavity (mouth)

-Gastric Gland-> Stomach

-Liver/ Gallbladder/Pancreas->Small intestines

Digestive Functions

-Ingestion

-Mechanical Digestion

-Propulsion

-Chemical Digestion

-Absorption

-Defecation

Ingestion

Intake into mouth

Mechanical Digestion

Breakdown of particles

-Mastication=chewing in mouth

-Segmentation= mixing food+ fluid w/in digestive tract

Where does mechanical digestion take place within the GI tract?

Oral cavity (mouth)

What is mastication?

chewing in mouth

What is segmentation?

mixing food+ fluid w/in digestive tract

Propulsion

Moving food through the digestive tract (towards the anus)

-Swallowing: voluntary and involuntary

-Peristalsis: waves of muscle contraction

-Moves food through digestive tract

What are the two forms of propulsion through the GI Tract?

Swallowing & Peristalsis

How is food moved through the GI tract?

Propulsion- Moving food through the digestive tract (towards the anus)

How do we prevent food from entering the nasal cavity or the larynx?

null

What is chemical digestion, and what is the general chemical type primarily used to breakdown food?

-Breakdown food by chemical reactions (enzymes).

Where does chemical digestion take place?

-Occurs in mouth, stomach, and intestines

Absorption

- Movement of particles into blood

Where does MOST of our nutrient absorption take place?

Small intestines

Defecation

-Elimination of waste

What is the difference between the incisors, canines, premolars, molars? AND what function does each have?

Teeth have various shapes for various food types

-Incisors

-Canine

-Premolar

-Molars

Incisors

blade-like; Used for biting food

Canine

Pointed (enlarged in carnivorous mammals); Used for grabbing food

Premolars

Characteristics of canines and molars; used for shearing food

Molars

Flattened with multiple roots; Used for grinding food and breaking down larger bites.

What is the hardest substance produced by the body, and where is it found?

Enamel- Teeth covered with it

What is salivary amylase, and what does it digest?

Salivary glands produce saliva with Salivary amylase; chemical digestion of carbohydrates.

Where along the GI tract does carbohydrate digestion first occur?

Oral cavity

With swallowing, how is food prevented from entering the nasal cavity or the trachea?

-Soft palate seals against pharynx to close off nasal cavity

-The epiglottis seals over opening to larynx

What is heartburn caused by?

Cardioesophageal sphincter weak

a. Stomach acids may move up into lower esophagus.

b. Acid reflux- Damage tissue

What type of mucosa is found within the esophagus?

Stratified squamous epithelia

What is the main function of the stomach?

Function in protein digestion

What is PEPSIN? What does pepsin breakdown?

Protein?

What is primarily absorbed across the stomach lining?

-Water

-Electrolytes

-Some drugs (aspirin)

-alcohol

How does the stomach prevent "self-destruction" from its acid environment?

Large amounts of mucus coats stomach to protect it

Do men or women absorb more alcohol from their stomach? Why?

Women->Females have less alcohol dehydrogenase than men. More alcohol in it's toxic form enters female blood.

What is the main function of the small intestines?

Absorb nutrients

How is the surface area for absorption increased within the small intestines?

-Plicae: Permanent ridges corkscrew" along inner surface of intestine

-Villi: Finger-like projections along surface; Have lacteal within to absorb fats

-Microvilli: Small projections along surface of columnar cells.

What are the 3 regions of the small intestines (from stomach to large intestine)?

-Duodenum-> First segment

-Jejunum-> Second segment

-ileum-> Third segment

Duodenum

-Duodenum-> Liver/ Pancreas secrete fluids into this segment

7-9 L of fluid

Enzyme "soup" with food

Jejunum

-Jejunum-> Most nutrient absorption occurs here

ILEUM

-ileum-> Leads to colon

Which of the 3 regions of the small intestine functions in the majority of nutrient absorption?

Jejunum-> Second segment

What is the main function of the large intestines?

-Water and vitamin absorption

-Compaction

-Defecatio

Where is the appendix located?

Attached to colon

What is the main function of the pancreas?

-Digests Carbohydrates, proteins, and fats

-enzymes neutralize acids from stomach

What are the functions of the liver?

-Largest visceral organ

-Remove toxins from blood (from digestive organs)

-Store and release glucose

-Produce most plasma proteins

-Produce Bile salts

Functions of the gallbladder?

Stores bile and bile salts

What is the function of bile salts?

-Help breakdown fats in small intestines

-Stored in gall bladder until needed

-Duct empties into duodenum

What organ produces bile salts? What organ stores bile salts?

Liver

Stored in gall bladder

About this deck

By: Alejandra Lopez
Created: 2010-11-30
Size: 49 flashcards
Views: 38

About StudyBlue

“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis