Unit 20- Digestive Systems

The digestive system is perhaps the best known of the organ systems. Responsible for processing and distribution of nutrients, this systems boasts the heaviest organ (the liver) and the greatest internal surface area.

Typesof digestion-

  1. intracellular digestion-
  1. extracellular digestion-
  1. basic extracellular-
  1. incomplete digestive systems-
  1. complete digestive system-

Complexity in Diet-Adaptations

herbivores / carnivores
diet
Teeth
Stomach
Intestine

Ruminants- hoofed mammals with a 4 part stomach ex: cattle, deer and goats

The Human GI Tract

GI= gastrointestinal= gut= digestive system

All gut organs are tubes of 3 layers

Peristalsis- defn-

Tracing the Movement of Food Through the System

  1. Ingestion-
  1. Mastication-

Tooth types-

  1. incisors-
  2. canines-
  3. molars-

In mastication saliva is added by the salivary glands

Saliva=

Tongue-

  1. Chemical digestion in the Mouth

Salivary amylase-

  1. swallowing-
  1. peristalsis
  2. cardiac sphincter
  1. In the Stomach

The stomach is an expandible muscular sac with many ______in the mucosa lining

Gastric glands have three cell types

  1. In the Small Intestine

Acid Chyme enters small intestine via the ______

The small intestine is a common area for the digestion process using enzymes form itself, the liver and the pancreas

Structure of the small intestine

Three sections-

  1. Duodenum-
  1. Jejunum-
  1. Ilium-

The mucosa of the small intestine is lined with millions of villi- each with a capillary and lacteal

  1. in the Liver-

The liver is the heaviest internal organ and is dense, brown and rich in blood and fat

The Liver has many functions-

  1. secretes bile-
  1. Hepatic Portal System- -
  2. stores glycogen-
  1. recycles old hemoglobin from the blood-
  1. breaks down proteins-
  1. manufactures blood proteins and cholesterol
  2. detoxifies poisons (alcohol) into metabolites -
  1. RE system-
  2. overall site of many aa, lipid and CHO metabolic processes

gall bladder- greenish bag hanging unde the liver- stores bile until use

gallstone-

bile duct-

  1. in the Pancreas

the pancreas is a white, spongy gland just below the stomach

** the pancreas is

Endocrine functions-

Structures called the ______ secrete:

  1. Insulin-
  1. Glucagon-

Diabetes-

Digestive Functions-______ source of enzymes and bicarbonate

Bicarbonate-

  1. trypsinogen =
  1. chymotrypsin -
  2. carboxypeptidases-
  3. pancreatic amylase-
  1. pancreatic lipase-
  2. esterase-
  3. ribonuclease and deoxyribonucleases-
  1. secretions of the Duodenum

The wall of the duodenum secretes its own enzymes

  1. Carboxypeptidases and Aminopeptidases-
  1. Maltase, Sucrase and Lactase-
  1. Hormonal Control of the System – a complex diagram
  1. so now that the chemical digestion has occurred it is time for absorption

This occurs in the Ilium and Jejunum of the Small Intestine

Amino Acids and Monosaccharides-

-

-

-

Hepatic Portal System-

Fatty Acids and Glycerol-

-Enter the Lymphatic system via lacteal

- eventually feed into Vena Cava

Any undigestibles and water leave the small intestine through the ______ and enter the large intestine

  1. In the large intestine

The common name of the large intestine is the ______

Parts-

appendix-

Functions of the colon-

1