digestive system
DESCRIPTION
Digestive System. Digestion. Introduction Physical Digestion Chemical Digestion Hepatic Portal System. Digestive System: Overview. Figure 24.1. Digestive Process. Figure 24.2. Figure 15.3. Essential Activities of Digestion. Figure 24.3a, b. Digestive Process. Figure 24.2. - PowerPoint PPT PresentationTRANSCRIPT
Digestive System
Digestion
• Introduction
• Physical Digestion
• Chemical Digestion
• Hepatic Portal System
Digestive System: Overview
Figure 24.1
Digestive Process
Figure 24.2
Figure 15.3
Essential Activities of Digestion
Figure 24.3a, b
Digestive Process
Figure 24.2
Mouth & Tongue
Figure 24.7a
Salivary Glands II
Figure 24.9a
Teeth
Figure 24.10.2
Digestive Processes in the Mouth
• Food is ingested
• Mechanical digestion begins mastication
• Propulsion is initiated by swallowing
• Salivary amylase
Deglutition (Swallowing)
Figure 24.13a-c
Thought Question
Esophagus
Figure 24.13d, e
Stomach
Figure 24.14a
Figure 15.17
Thought Question
Regulation of Gastric Secretion
• Stimulatory and inhibitory events occur in three phases– Cephalic (reflex) phase
– Gastric phase
– Intestinal phase
Cephalic Phase
• Excitatory events include:
• Inhibitory events include:
• Inputs come from olfactory receptors and taste buds hypothalamus vagal nuclei parasympathetic ganglion
Gastric Phase
• Excitatory events include:
• Inhibitory events include:
• Chemicals released– Gastrin
– Ach
– Histamine
Regulation and Mechanism of HCl Secretion
Figure 24.17
Gastric Contractile Activity
Figure 24.18
Intestinal Phase
• Excitatory phase
• Inhibitory phase
Regulation of Gastric Emptying
Figure 24.19
Microscopic Anatomy of the Small Intestine
Figure 24.21a-c
Figure 15.8
Figure 15.27
Figure 15.32
Figure 15.7
Large Intestine
Figure 24.29a
Chemical Digestion Carbohydrates
Figure 15.7
Chemical Digestion Protein
• Stomach– Pepsinogen Pepsin
• Small Intestine– Trypsin, Chymotrypsin, Carboxypeptidase– Brush Border Enzymes – Aminopeptidases– Carboxypeptidases
Thought Question
Figure 15.7
Chemical Digestion: Nucleic Acids
• Hydrolyzed to their nucleotide monomers by pancreatic nucleases present in pancreatic juice
• Absorption: active transport via membrane carriers– Absorbed in villi and transported to liver via hepatic
portal vein
• Enzymes used: pancreatic ribonucleases and deoxyribonuclease in the small intestines
Chemical Digestion of Fats
Figure 15.9
Figure 15.10
Figure 15.11
Fatty Acid Absorption
Figure 24.36
Pancreatic Enzymes
Hepatic Portal System
Thought Question
Summary
• Introduction
• Physical Digestion
• Chemical Digestion
• Hepatic Portal System