Animal Digestion

Flashcards about animal digestion

What are the three needs that satisfy an adequate diet?

1. Chemical energy for cellular processes, 2. Organic building blocks for macromolecules, 3. Essential nutrients

What are essential nutrients?

Required materials an animal requires but can’t assemble (i.e. amino acids, fatty acids, vitamins, minerals)

How many amino acids do organisms require, and how many can animals synthesize?

All organisms require 20 amino acids; most animals can synthesize around half of their amino acids.

What is an essential amino acid?

One that cannot be synthesized by cellular biochemical pathways and instead must be ingested.

How can animals extract the nutrients they need from food while not digesting their own tissues?

Compartmentalized processing protects body tissues while allowing enzymes and acids to break down nutrients.

What are the stages of food processing?

1. Ingestion, 2. Digestion, 3. Absorption, 4. Elimination

How are digestive tracts organized/divided?

Foregut (mouth, esophagus, stomach), Midgut (small intestine), Hindgut (large intestine, rectum)

What are the roles of: Foregut, midgut, hindgut?

Foregut: initial storage and digestion; Midgut: remainder of digestion and most nutrient absorption takes place; Hindgut: water/inorganic molecules absorbed, leaves waste products that are stored in the rectum are eliminated from body

What is peristalsis?

Active movement of food through the body using muscle contractions.

What are the layers of tissue in the digestive tract?

Lumen (central space), Mucosa (inner tissue layer), Submucosa (surrounds mucosa)

What is the role of gastric juice in the stomach?

Gastric juice has a pH of 2 and includes HCl and pepsin

What is the role of parietal cells in the stomach?

Secrete H and Cl ions separately

What is the role of chief cells in the stomach?

Secrete inactive pepsinogen, which is activated to pepsin when mixed with HCl.

What is the role of the liver in digestion?

Produces bile, which aids in fat digestion by breaking large clusters of fats into smaller lipid droplets (emulsification).

How does absorption work in the small intestine?

Large surface area (villi and microvilli), transport across the epithelial cells, and hepatic portal vein.

How are nutrient molecules like glucose absorbed in the intestine?

Glucose and amino acids are cotransported with sodium ions into intestinal cells

How does absorption occur in the large intestine?

Absorption of Na+ and Cl– ions creates an osmotic gradient, driving passive water absorption.

How does bacteria within the digestive tract aid digestion?

Bacteria aid in digesting nutrients the host cannot extract on its own, obtain nourishment from the host’s gut contents and produce essential nutrients and vitamins

What is dysbiosis?

Imbalances in the gut microbiota. It is linked to various diseases, including anxiety and depression, hypertension and cardiovascular diseases, obesity and diabetes, inflammatory bowel disease, cancer.

Define: Digestion

Food is isolated and broken down outside a cell in a body compartment

Define: Absorption

Following digestion, the breakdown products that are taken up into the bloodstream

Define: Lumen

Central space where gut contents travel

Define: Mucosa

Inner tissue layer w secretory and absorptive functions

Define: Submucosa

Surrounds mucosa; layer containing blood vessels, lymph vessels, and nerves

Define: Emulsification

The process of breaking down large fat globules into smaller, uniformly distributed droplets

Define: Hepatic portal vein

The vein that carries nutrient-rich blood from the villi capillaries to the liver, then to the heart

Define: Dysbiosis (of the gut)

An imbalance of microorganisms in the intestines, specifically a shift away from a healthy microbial community towards an unhealthy one