zoology( the book 1)
TRANSCRIPT
DIGESTION AND NUTRITION.
DIGESTION AND NUTRITION
All organism requires... ENERGY.
SUN – ultimate source of energy for life on earth.
DIGESTION AND NUTRITION
Autrophic
Heterotrophic
prototrophs
chemotrophs
DIGESTION AND NUTRITION
DIETARY HABITS:
- Herbivorous
- Omnivorous
- Carnivorous
- Saphrophagus
DIGESTION AND NUTRITION
Few animals can absorb nutrients directly from their external environments.
-Feeding on Particular Matter-Feeding on Food Masses-Feeding on Fluids
FEEDING MECHANISMS:
DIGESTION AND NUTRITION
(Feeding on Particular matter)
Suspension feeder- aquatic organisms that collect suspended food particles from the surrounding water; particles are filtered(filter feeding) or taken by other methods.
FEEDING MECHANISMS:
DIGESTION AND NUTRITION
(Feeding on Particular matter)
Deposit feeder- aquatic organisms that consume detritus and small organisms on soil or other sediments
FEEDING MECHANISMS:
(Feeding on Food Masses)
predators most locate, capture, hold and swallow prey.
carnivorous animals seize food and swallow it while some employ toxins that paralyze or kill prey upon capture.
FEEDING MECHANISMS: DIGESTION AND NUTRITION
(Feeding on Food Masses)
fishes, amphibians, and nonavian reptiles use their teeth to grip prey and prevent it’s escape until they can swallow it.
birds lack teeth, nut their beaks are often provided with serrated edges, or upper beak is hooked for seizing and tearing prey.
FEEDING MECHANISMS: DIGESTION AND NUTRITION
Biting, cutting and stripping
Seizing, piercing, and tearing Grinding and crushing
(Feeding on Fluids)
Fluid-feeding is especially characteristic of parasites. But it is practiced among many free-living forms as well.
FEEDING MECHANISMS: DIGESTION AND NUTRITION
DIGESTION AND NUTRITION
Purpose: reduce feed particles to molecules that can be absorbed into the blood
Digestion is the process of breaking down food into simple substances that can be absorbed by the body.
Absorption is the process of taking the digested parts of food into the bloodstream.
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
• Mechanical breakdown of food
• Chemical breakdown of food– HCl in the stomach– enzymes
• Contractions of digestive tract
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
In the mechanical phase, teeth or structures physically break down large pieces food into smaller pieces.
In the chemical phase, digestive chemicals called enzymes break apart individual molecules of food .
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
TYPES OF DIGESTION
Intracellular Digestion
The simplest invertebrates(animals without backbones)do not have specialized digestive organs. Single-celled organisms, such as amoebas, rely on intracellular digestion (digestion within the cell).
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
TYPES OF DIGESTION
Intracellular Digestion
A food particle is enclosed within a food vacuole by phagocytosis Food wastes are simply extruded from the cell by exocytosis.
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
TYPES OF DIGESTION
Intracellular Digestion more complex organisms require
systems that are more specialized. Animals such as jellyfish and nonparasitic flatworms combine the intracellular process with some specialized digestive organs.
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
TYPES OF DIGESTION
Extracellular DigestionMost of the more complex
invertebrates and all vertebrates (animals with a backbone) digest food entirely through extracellular (digestion outside the cell) processes.
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
TYPES OF DIGESTION
Extracellular Digestion Food moves in one direction, from
mouth to anus, through the series of organs that make up the alimentary canal.
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
TYPES OF DIGESTION
Extracellular Digestion Digestion is completed in the intestine . The
liver and pancreas pour their digestive juices into the anterior end of this organ. After the anterior intestine absorbs the usable products of digestion, the walls of the posterior intestine absorb leftover water.
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
TYPES OF DIGESTION
Extracellular Digestion In vertebrates the anterior intestine is
called the Small intestine ; the posterior intestine is the large intestine .Feces , composed of unabsorbed and indigestible food residues, form in the posterior intestine.
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
Animals classified by the type of stomach they have:
Monogastric or non-ruminants
Ruminants
Avian
Pseudo-ruminant
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
MONOGASTRIC ANIMALS• Monogastric(simple) – one or simple stomach
structure• mostly carnivores and omnivoresEg. Hogs, cat, dog
RUMINANT ANIMALS• Ruminant (polygastric)- 4 compartment stomach
with the compartments before the “true” stomach• • herbivoresEg. Cattle, sheep, goat
WHAT IS DIGESTION?
DIGESTION AND NUTRITION
AVIAN ANIMALS• is found in poultry ;differs greatly from any other
type.• Since a bird has no teeth, no chewing is involved.• Eg. Chicken.
PSEUDO-ROMINANT• An animal that eats large amounts of roughage but
does not have a stomach with several compartments.
• can utilize roughages because of an enlarged cecum and large intestine.
• Eg. Horse
WHAT IS DIGESTION?
DIGESTIVE SYSTEM
DIGESTIVE SYSTEM TYPES OF DIGESTIVE SYSTEM
Incomplete Type -when anus is absent, mouth serves for ingestion of food and egestion of waste materials
Complete Type- mouth and anus are present; may be subdivided into the digestive tract, the digestive glands, and the accessory structures
DIGESTIVE SYSTEM DIVISIONS OF THE COMPLETE TYPE
OF DIGESTIVE SYSTEM:
I. Coelom, Peritoneum, and Mesenteries
DIGESTIVE SYSTEM Coelom – cavity containg the visceral organs
Divided into:
a. small pericardial cavity – contains the heart
b. larger pleuro-peritoneal cavity – which contains the rest of the visceral organs
DIGESTIVE SYSTEM Peritoneum – connective tissue membrane that lines the coelomTypes: a. parietal peritoneum – lines the
body wall b. visceral peritoneum – covers
most visceral organs
DIGESTIVE SYSTEM Mesenteries -two layers of the peritoneum that suspends viscera from the dorsal body wall - name of organ they suspend Omentum -double membrane continuous with the mesenteries that connect the visceral organs with one another - also named after organ they connect.
II. Buccal Cavity
DIGESTIVE SYSTEM II. Buccal cavity:- large cavity exposed upon opening the mouth Parts: maxillary teeth – in the upper jaw sticky tongue – located at the floor of the
cavity which captures food and passes it on the esophageal opening
glottis – slit-like opening to the respiratory system and is found at the region between the tongue and esophageal opening
DIGESTIVE SYSTEM vocal sacs – where pair of slits lead to
; slits are located lateral to the glottis and near angle of jaw
choanae or internal nares- pair of holes at the roof of the buccal cavity
vomerine teeth- pair of v-shaped formations at the root of the mouth
Eustachian tube – opening or recess near the angle
III. Digestive tube:
DIGESTIVE SYSTEM III. Digestive tube:1.esophagus
– short tube connecting the oral cavity to the stomach2. Stomach
– bag shaped muscle
Parts of stomach:a. cardiac end – anterior portion continuous with the esophagus b. pyloric end – posterior portion continuous with the small intestinec. greater curvature – outer curvatured. lesser curvature – inner curvaturee. rugae – lines of the inner wall of the stomach
DIGESTIVE SYSTEM 3. pyloric sphincter – constriction at the junction of the stomach
and the small intestine 4. Small Intestine - digestive tube that has become the long
coiled structure from the pylorus - where most chemical digestion and
absorption occurs Has 2 regions: a. duodenum – bends anteriorly from the
pylorus and runs parallel to the stomach b. ileum – longer and posterior
DIGESTIVE SYSTEM 5. Large Intestine - where digestive tube enlarges - further breakdown of undigested
material by bacterial action and the absorption of water occur here
6. Cloaca – short narrow tube which opens to
the outside through the anus - urine and gametes also pass
through the cloaca and anus
DIGESTIVE SYSTEM
Mesenteries found in digestive system
dorsal mesentery – digestive tube is suspended from the dorsal body
mesogaster – mesenteries in the stomach at its cardiac end
mesentery proper or mesenterium – suspends the ileum
mesorectum – suspends rectum
7. Spleen – dark lymphoid organ lying within the fold of the
mesorectum
DIGESTIVE SYSTEM IV. The digestive glands: Liver- largest gland in the body -function: secretes bile, and monitor and
controls the balance of the body by removing the toxins in the body.
- Has three lobes: a left lobe subdivided into anterior and posterior
lobules a small right lobe much reduced median lobe Gall bladder- stores the bile secreted by the liver Bile- emulsifies fat, neutralizes the acidic food
entering the intestine and creates pH favorable for pancreatic and intestinal enzyme action.
Pancreas- digestive gland and an endocrine gland
DIGESTIVE SYSTEM As a digestive gland: Secretes pancreatic juice which contains several
enzymes for the chemical breakdown of food. These enzymes include lipase,
deoxyribonuclease, amylase and carboxypeptidase
As an endocrine gland: Secretes insulin Common Bile Duct- formed by the union of the
cystic duct of the gall bladder, the hepatic duct, and the pancreatic ducts
- Enters the anterior portion of the duodenum