Download presentation
Presentation is loading. Please wait.
1
The great Serengeti migration: A quest for minerals
anphys-opener-04-0.jpg
2
Digestive system Functions Organs
3
Organs of alimentary canal
Figure 23.2
4
Month Esophagus Stomach Small intestine Large intestine Accessory organs Salivary glands, liver, pancreas, gall bladder Figure 23.1
5
Digestive tracts of various vertebrates
6
Digestive tracts of invertebrates and vertebrates
7
Figure 4.1 The composition of the adult human body
anphys-fig jpg
8
Nutrition Proteins Lipids Carbohydrates Vitamins and minerals
9
Figure 4.2 Amino acid chemistry (Part 1)
anphys-fig jpg
10
Figure 4.2 Amino acid chemistry (Part 2)
anphys-fig jpg
11
Figure 4.3 Fatty acids and triacylglycerols (Part 1)
anphys-fig jpg
12
Figure 4.3 Fatty acids and triacylglycerols (Part 2)
anphys-fig jpg
13
Figure 4.4 Carbohydrate chemistry
anphys-fig jpg
14
Figure 4.5 Vitamin structures
anphys-fig jpg
15
Examples of feeding adaptations Food chains
16
Figure 4.6 Some species feed by targeting and subduing individual food items (Part 1)
anphys-fig jpg
17
Figure 4.7 Specialization of a vertebrate feeding apparatus
anphys-fig jpg
18
Dentition
19
Figure 4.8 Specialization of an invertebrate feeding apparatus (Part 1)
anphys-fig jpg
20
Figure 4.8 Specialization of an invertebrate feeding apparatus (Part 2)
anphys-fig jpg
21
Figure 4.10 The feeding apparatus of a baleen whale
anphys-fig jpg
22
Figure 4.12 Reef-building corals of warm waters need light because they are symbiotic with algae (2)
anphys-fig jpg
23
Figure 4.9 Short food chains deplete energy less than long food chains do
anphys-fig jpg
24
Digestive systems of insects and crustaceans
Crustaceans’ digestive system is separate from the excretory system Insects– the Malpighian tubules – excretory system is connected at the junction of the midgut and hindgut
25
Figure 4.16 The digestive systems of two types of arthropods: insects and crustaceans
anphys-fig jpg
27
Figure 23.1
28
Contractions of the stomach churn chyme.
Stomach (continued) Contractions of the stomach churn chyme. Mix chyme with gastric secretions. Push food into intestine. Insert fig. 18.5
29
Each villus is a fold in the mucosa.
Small Intestine Each villus is a fold in the mucosa. Covered with columnar epithelial cells interspersed with goblet cells. Epithelial cells at the tips of villi are exfoliated and replaced by mitosis in crypt of Lieberkuhn. Lamina propria contain lymphocytes, capillaries, and central lacteal. Insert fig
30
Histology of the Alimentary Canal
Figure 23.6
31
Sensors of the GI tract– regulatory mechanisms
Mechanoreceptors and chemoreceptors involved Located in the walls of the tract organs Sensors respond to Stretching Osmolarity pH Presence of substrates and end-products
32
Regulatory mechanisms (2)
Receptors initiate reflexes Activate of inhibit glands that secrete digestive juices Stimulate smooth muscle of GI tract Move food along the tract Mix lumen content
33
Peristalsis and Segmentation
Figure 23.3
34
Adaptation associated with animal’s diet
Microbe-assisted digestion –animals in hydrothermal vents-trophosomes Dentition/mouth parts Length of digestive tract Herbivores Carnivores Omnivores Sharks Birds
35
Microbe-dependent digestion
Digestion assisted by microbes
36
Animals maintain symbiosis with three categories of microbes
Heterotrophic microbes Organic compounds of external origin Autotrophic microbes Synthesize organic molecules from inorganic precursors Chemosynthetic Photosynthetic
37
Figure 4.13 Hydrothermal-vent worms are symbiotic with chemoautotrophic bacteria (Part 1)
anphys-fig jpg
38
Hydrothermal-vent worms
Symbiotic with chemoautotrophic bacteria- trophosomes Worms have not mouth, gut, or anus Food comes from sulfur-oxidizing chemoautotrophic bacteria Organic molecules from bacteria meets nutritional needs Vents- source of H2S
39
Hydrothermal-vent worms
Symbiotic with chemoautotrophic bacteria- trophosomes Worms have not mouth, gut, or anus Food comes from sulfur-oxidizing chemoautotrophic bacteria Organic molecules from bacteria meets nutritional needs Vents- source of H2S
40
Figure 4.13 Hydrothermal-vent worms are symbiotic with chemoautotrophic bacteria (Part 2)
anphys-fig jpg
41
Comparison of the digestive tracts of carnivores and herbivores
Carnivores- foregut digestion Herbivores Hindgut Foregut
42
Figure 4.14 The digestive tract of ruminants (Part 1)
anphys-fig jpg
43
Rumen – first chamber/fermentation occurs
Stomach of ruminants Several chambers Rumen – first chamber/fermentation occurs Regurgitate fermenting materials from the rumen into mouth Further grinding and reswallow From rumen reticulum omasum abomasum (true stomach)
44
Functions of microbes in ruminants
Synthesize B vitamins, essential amino acids Fermentative breakdown of compounds that animals cannot digest– cellulose Recycle waste nitrogen from animal metabolism Make ammonia so other microbes can use it as nitrogen source
45
Figure 4.14 The digestive tract of ruminants (Part 2)
anphys-fig jpg
46
Figure 4.15 The digestive tracts of two hindgut fermenters
anphys-fig jpg
47
Hind and midgut fermenters
Enlarged cecum/colon Rabbits, horses, zebras, rhinos, apes, elephants Break down of cellulose and carbohydrates Forms short-chain fatty acid B vitamins- not utilized, lost in feces Coprophagy– rabbits eat special soft feces
48
A comparison of the digestive tracts of a carnivore (coyote) and a herbivore (koala)
49
Digestion and absorption
Digestive enzymes in 3 spatial contexts Intraluminal enzymes Membrane-associated enzymes Intracellular enzymes
50
Intracellular and extracellular digestion
Intraluminal and membrane-associated enzymes are responsible for extracellular digestion Intracellular enzymes are responsible for intracellular digestion Advantages and disadvantages of intra- and extracellular digestions?
51
Figure 4.17 The stomach of a clam (Part 2)
anphys-fig jpg
52
Carbohydrate digestion
Organ Substrate Enzyme End product(s) Oral cavity Starch Sal1vary amylase Maltose Stomach Amylase denatured Lumen of intestine Undigested polysaccharides Pancreatic amylase Brush border of small intestine Disaacharides: maltose Sucrose Lactose Maltase Sucrase Lactase Monosaccharides
53
Figure 4.19 Absorption of monosaccharides in the vertebrate midgut (Part 2)
anphys-fig jpg
54
Protein digestion Organ Substrate Enzyme End product(s) Stomach
Organ Substrate Enzyme End product(s) Stomach Polypeptides Pepsinogen +HCl = pepsin Smaller peptides Lumen of intestine Trypsinogen, chymotrypsinogen (inactive enzymes released from the pancreas, transported to duodenum via pancreatic duct. These enzymes are activated by enterokinase from small intestine to trypsin and chymotrypsin Smaller polypeptides Aminopeptidase, carboxypeptidase Amino acids Brush border of small intestine Dipeptides Dipeptidase
55
Figure 4.18 The digestion of a short protein by three pancreatic peptidases
anphys-fig jpg
56
Fat digestion Organ Substrate Enzyme End product(s) Oral cavity
Fat digestion Organ Substrate Enzyme End product(s) Oral cavity No enzyme to digest fat Stomach Lumen of intestine Fat globules Bile salt from gallbladder lipase Emulsified fat Glycerol, fatty acids Brush border of small intestine
57
Chemical Digestion: Fats
Figure 23.35
58
Figure 4.19 Absorption of monosaccharides in the vertebrate midgut (Part 1)
anphys-fig jpg
59
Chemical Digestion: Carbohydrates
Carbohydrates absorption: via cotransport with Na+, and facilitated diffusion Enter the capillary bed in the villi Transported to the liver via the hepatic portal vein
60
Chemical Digestion: Proteins
Absorption: similar to carbohydrates Enzymes used: pepsin in the stomach Enzymes acting in the small intestine
61
Chemical Digestion: Fats
Absorption: Diffusion into intestinal cells where they: Combine with proteins and extrude chylomicrons Enter lacteals and are transported to systemic circulation via lymph
62
Coordination of digestion– neural and endocrine control
Controls of digestive activity Extrinsic Central nervous system and autonomic nervous system Intrinsic Hormone-producing cells in stomach and small intestine Distributed via blood and interstitial fluid to target cells
64
Endocrine control Gastrin Secretin CCK GIP Where? When? Why? How?
65
Figure 4.20 GI function after a meal is coordinated in part by hormones secreted by cells in the gut
anphys-fig jpg
Similar presentations
