Animal Nutrition: Systems and Processes

Animal Nutrition and Introduction

• Animal nutrition encompasses the processes by which animals obtain and utilize nutrients for energy, growth, maintenance, and reproduction
• The respiratory system captures oxygen needed for cells and removes carbon dioxide from cellular metabolism.
• The digestive system introduces food, prepares it, and transforms it for distribution to all cells, eliminating non-assimilated materials
• The excretory system expels waste products
• The circulatory system transports nutrients and oxygen to cells while removing waste and carbon dioxide.
• Nutrients go to cells
• Digestion/absorption, gas exchange, substance transport, and excretion are processes involved in nutrition.
• Obtaining nutrients involves capturing them from the environment.

Nutrient Capture and Ingestion

• Animals use different strategies for nutrient capture and ingestion.
• Passive capture involves directly absorbing nutrients or filtering them from water.
• Direct absorption of nutrients occurs across the body surface
• Active capture involves using tentacles or specialized buccal structures

Digestion and Absorption

• Extracellular digestion involves breaking down food outside cells
• Mechanical digestion involves trituration and mixing with saliva and digestive juices
• Chemical digestion involves breaking complex molecules into simpler ones using digestive enzymes.
• Nutrients traverse the digestive tract wall.
• Intracellular digestion is only available in the simplest animals.

Digestive Systems

• Simple digestive systems include Porifera (sponges), which lack a digestive system and rely on intracellular digestion
• Simple digestive systems can include a gastrovascular cavity with one opening
• A digestive tract can be without glands and have a tract with an entrance and exit and specialized sections
• Digestive tubes with glands feature specialized regions and glands that secrete digestive fluids
• Vertebrates organize digestive systems featuring mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

Vertebrate Mouths

• Vertebrate mouths have buccal structures (teeth/beaks) for food capture and ingestion.
• The tongue aids in capture, ingestion, food management, and chemical perception.
• Salivary glands in the mouth secrete saliva to lubricate food and initiate chemical digestion.

Pharynx and Esophagus

• The pharynx is shared with the respiratory system and communicates with the esophagus, larynx, nasal cavity, and middle ear.
• The epiglottis prevents food from entering the larynx.
• The esophagus has muscular walls that facilitate food movement.

Stomach

• Mechanical digestion occurs through contractions
• Chemical digestion is reliant on gastric juices
• Gastric juices are made up of mucus, hydrochloric acid, and enzymes

Intestines

• The small intestine is longer in herbivores and divided into the duodenum, jejunum, and ileum
• Repliegues of the inner intestinal walls (vellosidades intestinales) assist with nutrient absorprotion
• Microvellosidades then further aid with the surface area of absorption

Intestinal Glands and Secretions

• Intestinal glands secrete intestinal juices containing antibacterial and mucus that is protective of the duodenum
• The pancreas secretes pancreatic juice containing bicarbonate and digestive enzymes.
• The liver secretes bile to emulsify fats for digestion.

Progressive Digestion

• Saliva begins digestion in the mouth converting to a bolus
• Gastric juice continues the process in the stomach becoming chyme
• Bile, pancreatic juice and intestinal enzymes all combine in the small intestine to form a a chyle.

Waste Removal

• Fiber that can not be broken down moves into the large intestine and prepares for excretion.
• In the colon, water is mainly absorbed until the waste material is read to process to the outside of the organism

Gas Exchange

• For animals, gas exchange involves capturing nutrients (O2) and expelling waste (CO2)
• Simple diffusion of gases occurs in more simple organisms, while animals use respiritory systems

Respiration Types and Systems

• Cutaneous respiration occurs directly through the skin if it is wet
• Tracheal respiration does not involve fluids, but instead uses tracheas.
• Branchial respiration is specialized in exchanging gases in water
• Pulmonary respiration specializes in exchanging air gases

Mammal Systems

• Respiration involves various pathways such as the nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli, and lungs
• Alveoli in the lungs are surrounded by capillaries for gas exchange
• The contraction of rib muscles and the diaphragm assist with air flow
• The relaxation of these muscles then pushes the air out

Substance Transport

• Transports of hormones and nutrients
• Provides defense of the organism
• Assists in maintaining pH, concentration and regulation of body heat

Components of Ciculatory System

• Fluid to circulate
• Conduits to flow thru
• Bomba impulse

Circulatory Systems

• Open circulatory systems feature vessels that empty to lagoons, which is propreitary to arthropoda
• Closed circulatory systems are used by vertabrates with closed vessels and single or double chamber hearts

Hearts

• The heart features a single chambered hear that goes to the organs
• A double circut heart flows to lungs first then to organs

Mamilian

• Pulminary circuation is first, flows thru the lungs, then through arteries

The cardiac system

• Consist of sistol and diastole with stages

Excretion introduction

• In animals, secretion assists with waste disposal and fluid and homeostatic regulation
• This is dependent on different aparatuses

Products of waste

• Products of waste include carbon dixoide, water, mineral salts, and nitrogens

Types of Nitrogenous Waste

• Ammoniotelic animals excrete ammonia
• Ureotelic animals excrete urea
• Uricotelic animals excrete uric acid

Excretion Types

• Protonephridia are branched tubules that connect pores to the exterior
• Metanephridia have conduits that collect waste with a nephridiophore that eleiminates for each segment
• Malpighi tubules are connectted to the digestiove areas, and thus eleiminated in the digestive tract

Excretion Systems

• Mesonepros uses a similar system of filtration in the glomerulus system for peices
• Metanephros uses a more advanced system that requires nephrons

Mammilain Excretion

• Requires a collection of waste
• This is sent to two kidnesy
• Travels thru the ureter into the bladder and releases Estructura
• 1 outer
• 2 cortex
• 3 canal Consist of different parts

Filtration types

• Glomerulus - contains high pressure for filtration Containe
• Agua
• Pequeñas
• Reabsorption requires a vessel as well

Excretion

• Glumerious then cleans out and helps create pee