Invertebrate Digestion:
FIrst true extracellular digestion occurs in ___
nematoda
More advanced invertebrates have other less advanced digestive tracts.
True or False
False:
more advanced
Classes of vertebrates
fish (pisces)
amph.
rept.
birds
mammals
Characteristics of advanced digestion
a.One way flow
i.Two openings
1.In one end; out the other
b.Digestion coupled with absorption
i.Digestive products get absorbed into the body
1.It has to be absorbed through the tract to go to the rest of the body
a.If it remains inside the canal, the body doesn’t get it
Wall of digestive tract layers from inside to outside
tunica...
- mucosa
- submucosa
- muscularis
- adventitia (or serosa in some areas)
Explain the tunica mucosa:
type of membrane
lines what
what tissue
1.mucous membrane
a.lines cavities that open to the exterior
i.epithelial tissue lines the lumen
ii.In humans, its simple columnar epithelim
iii.Goblet cells produce the mucus
tunica mucosa function
1.Glandular layer
a.Produces and secretes the digestive juices
2.Since it’s a mucous membrane, its protective in nature
a.Protects it from being digested itself
tunica submucosa
general description
i.A connective tissue layer that contains BV, lymphatic vessels, and nerves
tunica submucosa
function of vessels
1.Vessels are there to get the absorbed materials and transport them
a.Pick up the nutrients that were absorbed through the wall of the tract and transport them to the body
tunica submucosa
Nerve function
1.Nerves are part of the autonomic nervous system
a.Two divisions
i.Parasympathetic
ii.– rest and relaxation; increases digestion
iii.Sympathetic
iv.– inhibits digestion; “fight/ flight”
b.Control smooth muscle, cardiac muscle, and glands
i.Nerves are going to control movement of tube and release of digestive juices
tunica muscularis
types of muscle
i.Most part: it is smooth muscle
ii.At beginning and end of tube, its skeletal muscle, but most of it is smooth muscle
1.Even that skeletal muscle is barely under control
tunica muscularis
function
i.Function: movement
1.Peristalsis
a.Rhythmic movement of food from one part of the tube to the next
2.In stomach, there is another type of movement called churning
a.Where the food is thrown from side-to-side, top to bottom in the stomach because you want to change the bolus (solid mass that you swallow) into a more liquid fluid, chyme
tunica adventitia
i.Connective tissue layer
ii.Located all places except the abdominal pelvic level, where its called the tunica serosa, which is the peritoneum, which is also connective tissue
tunica adventitia
Compare two types
i.In both adventitia and serosa, it’s a binding tissue
1.Binds organs to wall of body
2.Binds blood vessels and nerves to wall of the tube
tunica adventitia
Contrast two
1.Adventitia: just connective tissue
a.Esophagus, mouth, pharynx
2.Abdominal pelvic region: it’s a serous membrane
tunica serosa
description
a.Tunica serosa called the peritoneum
b.Not only connective tissue, but epithelium
c.Every serous membrane has two layers
i.Outer, called parietal layer called parietal peritoneum
ii.Inner, called visceral layer called visceral peritoneum
iii.In between is a space where serous fluid exists, which is watery
iv.Simple squamous called mesothelium in the wall of a serous membrane
tunica serosa function
a.Serosa’s function is to reduce friction as the organs move in the cavity
i.Present in abdominal pelvic region for digestion: small intestine, large intestine, stomach
Author
DesLee26
ID
197815
Card Set
Invertebrate/ Vertebrate Digestion Layers of tract