1. The Digestive System And Nutrition
6.2
The
Digestive System
And Nutrition
Sonia Osuna, Emily Brenchley,
Alex Gupton, and Lauren Anderson

2. Nutrition Herbivores- Eat plants and or algae
Animals fall into one of three categories of how they get nutrition
Herbivores- Eat plants and or algae
Carnivores- Eat other animals
Omnivores- Eat animals and plants/algae

3. Specialized Teeth
Animal’s Dentition, or their assortment of teeth, are structure variations that determine an animal’s specialized diet.
Mammals have highly specialized
teeth, which makes them successful
Nonmammalian vertebrates also
Have specialized teeth,
but to a lesser extent.

4. Carnivore
Herbivore
Omnivore
Incisors
Canines
Premolars
Molars

5. These are required by all cells and come from an animal’s diet
Essential Nutrients
Four classes:
Amino Acids
Fatty Acids
Vitamins
Minerals
These are required by all cells and come from an animal’s diet

6. Amino Acids
Animals require 20 Amino Acids, but can only synthesize half from from molecules
The ones that can’t be synthesized are known as the Essential Amino Acids and have to be obtained fully built from food
Foods that can provide these essential building blocks are things like eggs, meat, and cheese

8. Fatty Acids
These are used for different cellular components such as phospholipid membranes, storage fats, and signaling molecules in animals
Plants can synthesize essential fatty acids

9. Vitamins
Vitamins are organic molecule that the body only requires small amounts of.
Humans require 13 different Vitamins
Two Groups:
Fat-soluble
Water-soluble

10. Minerals Inorganic nutrients Only required in small amounts
Ingesting too many leads to homeostatic imbalances.

11. Nutritional Needs
Malnutrition occurs when the body doesn’t get enough of the essential nutrients
Deficiencies in essential nutrients can cause deformities, disease, and death
Epidemiology- the study of human health and disease in populations

12. Types Of Feeders
Filter- They feed by straining food particles and water through a specialized structure. Sponges are among this group.
Substrate- These types of feeders live in or on what they eat. Termites are an example of this.
Fluid- Feed on a host. This could be something like mosquitos or leeches
Bulk- Feeding on animals or plants is bulk feeding. Humans do this and many other animals.

13. Parts of Digestion
Digestion-is the process of breaking food down into molecules small enough to absorb. There are 2 stages of digestion, mechanical and chemical.
Absorption- The uptake of nutrients by the bodies cells.
Elimination- The removal of undigested materials from the body.

14. Intracellular Vs. Extracellular Digestion
Intracellular Digestion
Extracellular Digestion
-Food Particles are engulfed by phagocytosis - food vacuoles fuse with lysosomes containing hydrolytic enzymes.
-Extracellular digestion takes place outside of cells.
-Completed in compartments, some have stomachs and things like that, others have a gastrovascular activity. The gastrovascular cavity does digestion and distributing nutrients to the cells of the body.

15. Mammal Digestive System
alimentary canals- specialized regions that carry out digestion and absorption
accessory glands secrete digestive juices through digestive ducts.
-Accessory glands include: Salivary glands, the pancreas, the liver and the gallbladder.
-Peristalsis: Muscle contractions move food through the system
-sphincters regulate movement of material between compartments.

16. Mechanical Digestion Takes place in the oral cavity
Teeth break down the food into smaller pieces so it may mix with saliva
The Salivary Glands release saliva, a mucous made of water, salts, glycoproteins, and salivary amylase-- which begins to break down glucose polymers and starches.

18. Swallowing
The tongue shapes food into a bolus and provides help with swallowing
The throat, or pharynx, is the junction that opens to both the esophagus and the trachea
The esophagus, which is connected to the stomach, will rhythmically contract to push the bolus down.

21. 1) Ingestion 2) Digestion 3)Absorption 4) Elimination
Nutrient molecules enter body cells
Mechanical
Digestion
Chemical Digestion (enzymatic hydrolysis)
Undigested materials
1) Ingestion ) Digestion )Absorption ) Elimination

22. The Stomach and Chemical Digestion
Gastric juices in the stomach mix with food to create Chyme, which has an oatmeal consistency
Gastric juice is made up of hydrochloric acid (HCl) and pepsin
Pepsin is a protease, or protein-digesting enzyme, that cleaves proteins into smaller peptides
The pH of gastric juice is 2, acidic enough to kill bacteria and denature proteins

23. Coordinated contraction and relaxation of stomach muscle churn the stomach’s contents
Sphincters prevent chyme from entering the esophagus and regulate its entry into the small intestine
Stomach contents typically pass into the small intestine 2–6 hours after a meal

24. Stomach Lining
Due to the high pH of stomach acid, the interior of a stomach contains a lining to protect itself and the body.
A layer of mucous covers the lining to protect it
A new epithelial layer is made every 3 days to replace the damaged one

26. Small Intestine
The small intestine is the major organ of digestion and absorption
It’s the longest section of the alimentary cavity
First section of the intestine is know as the duodenum
Chyme mixes with digestive juices from the pancreas, liver, gallbladder, and intestinal walls.

27. The inner lining of the duodenum also produces digestive enzymes
Digestion is finished as the chyme is moved along the small intestine through peristalsis.
After digestion is finished in the duodenum, absorption takes place in the jejunum and ileum of the small intestine.
The villi and microvilli protections within the intestine increase surface area and therefore speed up absorption.

29. Liver/Gallbladder Roles
The liver produces Bile to be used in the digestion and absorption of fats
Bile will also destroy non functional red blood cells.
This Bile is stored in the gallbladder

30. Liver
The hepatic portal vein carries nutrient-rich blood from the capillaries of the villi to the liver, then to the heart
The liver regulates nutrient distribution, interconverts many organic molecules, and detoxifies many organic molecules

31. Pancreas
The pancreas produces trypsin and chymotrypsin which are alkaline substances that neutralize the very acidic Chyme.

33. Large Intestine
The colon of the large intestine is connected to the small intestine
The cecum aids in the fermentation of plant material and connects where the small and large intestines meet
The human cecum has an extension called the appendix, which plays a very minor role in immunity

34. Absorption in the large intestine
The colon functions to absorb leftover water that has entered the alimentary cavity
Water is absorbed from the undigested material and bacteria, now called Feces
It is also home to Escherichia coli, a bacteria that lived on organic material and produce vitamins for the body

35. Rectum and Feces
Feces are stored in the rectum until they can be eliminated through the anus
Two sphincters between the rectum and anus control bowel movements

36. Mutualism
Many herbivores have fermentation chambers in their alimentary canals, where mutualistic microorganisms digest cellulose Rabbits and some rodents harbor mutualistic bacteria in their large intestines and ceca The most elaborate adaptations for an herbivorous diet have evolved in the animals called ruminants, including deer, sheep, and cattle. They can ferment plant based nutrients to later absorb them

37. Rumen
Reticulum
Intestine
Omasum
Abomasum

38. Adaptations And Feedback
Many carnivores have large, expandable stomachs
Herbivores and omnivores generally have longer alimentary canals than carnivores, reflecting the longer time needed to digest vegetation

40. Regulation Each step in the digestive system is activated as needed
The enteric division of the nervous system helps to regulate the digestive process
The endocrine system also regulates digestion through the release and transport of hormones

42. Metabolism
Bioenergetics-- The flow and transformation of energy in an animal
*how fast it is determines nutritional needs*
An animal’s energy use per unit of time is called its metabolic rate Metabolic rate can be determined by monitoring an animal’s rate of heat loss, the amount of O2 consumed, or the amount of CO2 produced

43. Animals must maintain a minimum metabolic rate for basic cell functions
Basal metabolic rate, BMR, is the minimum metabolic rate of a non growing endotherm that is at rest, has an empty stomach, and is not experiencing stress
standard metabolic rate, SMR, is the metabolic rate of a fasting, non stressed ectotherm at a particular temperature

44. Energy Storage
In humans, the liver and muscle cells are used first; energy is stored as glycogen
When glycogen deposits are full, additional excess energy is stored as fat in adipose cells
When fewer calories are taken in than expended, the body expends liver glycogen, muscle glycogen, and then fat.

46. Glucose Homeostasis Insulin and glucagon maintain glucose levels
Insulin levels rise after a carbohydrate-rich meal, and glucose entering the liver through the hepatic portal vein is used to synthesize glycogen
When glucose concentration is low in the hepatic portal vein, glucagon stimulates the liver to break down glycogen and release glucose into the blood
Insulin and glucagon are produced in the pancreas

48. Diabetes Mellitus
Diabetes Mellitus is a disease caused by insulin deficiency, or a decreased response to insulin.
Cells are not able to take up glucose to maintain metabolism
There are several types and caused to this

49. Types of Diabetes
Type 1 diabetes (juvenile diabetes) is an autoimmune disorder in which the immune system destroys the pancreatic beta cells so no insulin is released
Type 2 diabetes (adult onset) is characterized by a failure of target cells to respond normally to insulin
Heredity is a factor in type 2 diabetes Excess body weight and lack of exercise increase the risk

50. Obesity
Overnourishment causes Obesity, as the excessive energy is stored as fat
This contributes to type 2 diabetes, cancer, heart attacks, and strokes

51. Appetite Regulation Hormones
Ghrelin- Triggers feelings of hunger; secreted by the stomach
Insulin- Suppress appetite
PYY- Suppress appetite; secreted by the small intestine after a meal
Leptin- Suppresses appetite and regulates body fat levels; produced by adipose tissue

52. The End