Digestion - in deep by Kait Weston https://padlet.com/kaityates/PreUDigestion An overview of Pre U Digestion and Nutrition. Remember to put your name in your posts en-us 2018-02-09 09:17:44 UTC 2026-01-24 23:43:32 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Apple.png Pancreas kaityates https://padlet.com/kaityates/PreUDigestion/wish/229941747 Endocrine (ductless - secretions directly into blood) and exocrine (substances secreted into a duct) gland]]> 2018-02-09 09:22:20 UTC https://padlet.com/kaityates/PreUDigestion/wish/229941747 Digestive System Part 1 raineye1 https://padlet.com/kaityates/PreUDigestion/wish/229944793 2018-02-09 09:33:17 UTC https://padlet.com/kaityates/PreUDigestion/wish/229944793 Large Intestine - Toby and Gemma PART 1 https://padlet.com/kaityates/PreUDigestion/wish/229944913 Size- Herbivores have a very large and complex, Omnivores have a substantial sized large intestine, and carnivores have a small large intestine.
Surface Area: Large intestine is devoid of villi.
Stem cells: support the continual renewal of the epithelium
Main Functions:
  • Recovery of water - 90% of water is absorbed by the ileum, but water and sodium and chloride electrolytes are absorbede in the large intestine
  • Formation and Storage of Faeces - Ingesta is moved through the large intestine, its dehydrated, mixed with bacteria and mucous and formed into faeces
  • Microbial Fermentation - large intestine of all species has microbial life, which produce enzymes that many molecules that vertebrates are indegestable (cellulose). 

Caecum: Blind Pouch, Several species of bacteria- large bowel synthesize cellulases and digests cellulose. End products of mircrobial cellulose digestion - Volatile fatty acids which are absorbed by the colon. Fermentation a major source of intestinal gas. Carnivores/Omnivores - fermentation makes very few calories. In herbivores fermentation very present.
R3ctum: Controlled by 2 sphnicter: Inner (smooth muscle, involuntary) Outer (straightened muscle, voluntary). Faeces is 75% water, 25% Solid (mainly bacteria and undigested organic matter).

]]> 2018-02-09 09:33:43 UTC https://padlet.com/kaityates/PreUDigestion/wish/229944913 Stockerrr and Arron-Exocrine secretions of the pancreas lewisa26 https://padlet.com/kaityates/PreUDigestion/wish/229945195 Digestive enzymes secreted by the pancreas include Proteases, Pancreatic Lipase, Amylase, ribonuclease, deoxyribonuclease, gelatinase, elastease]]> 2018-02-09 09:34:53 UTC https://padlet.com/kaityates/PreUDigestion/wish/229945195 Structure of Stomach- its functions in digestion and absorption- Katie https://padlet.com/kaityates/PreUDigestion/wish/229946510 Food is stored in the stomach where it is converted to chyme.
If the food isn't too fatty it will be kept in the stomach for around 4 hours.
The outflow of food - to the duodenum- is controlled by the pyloric sphincter.
Length- 15-25cm
Volume- 50ml (when empty) 5L (when full)
Rugae - the folds of mucosa and submucosa which gives the stomach a cross section only slightly larger than the large intestine.
Major Regions:
  • Cardiac Sphincter - from the oesophagus it relaxes which allows the food to enter. 
  • Cardiac Region - where the food enters from the oesophagus.
  • Fundus - domed shape and is located under the diaphragm.
  • Pyloric region - it ends with the pyloric sphincter that controls the passage of chyme into the duodenum.
  • Mesenteric Covering - known as the 'fatty skin' that covers the stomach and contains a large number of lymph nodes (give protection).


]]> 2018-02-09 09:39:34 UTC https://padlet.com/kaityates/PreUDigestion/wish/229946510 Brandon and Jack-Pancreas structure https://padlet.com/kaityates/PreUDigestion/wish/229947536 The pancreas is both an endocrine and exocrine organ.  Insulin and glucagon  are secreted by the  endocrine gland. The pancreas has Islets of Langerhans with endocrine cells Alpha and Beta cells. Alpha cells produce glucagon and Beta cells produce insulin.
pancreas is surrounded by capule of connective tissue which makes glads form septae. these divide pancreas into lobules. The space between lobules are called artefacts. The cells that synthesize and secrete digestive enzymes are arranged in grape-like clusters called acini.
  •    Islets of Langerhans
    f

]]> 2018-02-09 09:43:10 UTC https://padlet.com/kaityates/PreUDigestion/wish/229947536 Small Intestine - Charlie and Ayesha https://padlet.com/kaityates/PreUDigestion/wish/229947754 - Major digestive organ
- Extends from pyloric sphincter to ileocaecal valve. (separates small + large intestine)
- Circular + Longitudinal muscles move liquid food by peristalsis + mix contents by pendular movements.]]> 2018-02-09 09:43:52 UTC https://padlet.com/kaityates/PreUDigestion/wish/229947754 Mucosa raineye1 https://padlet.com/kaityates/PreUDigestion/wish/229948538 Structure- Moist epithelial membrane on inner surface, simple columnr, rich in goblet cells. Lines Lumen. Underneath epitheial membrane is lamina propria is made of loose connective tissue. Outside this layer is Muscularis mucosae; thin layer of smooth muscle tissue which produce local movement of intestine.]]> 2018-02-09 09:46:17 UTC https://padlet.com/kaityates/PreUDigestion/wish/229948538 Proteases lewisa26 https://padlet.com/kaityates/PreUDigestion/wish/229948624 These are responsible for the bulk of protein digestion, they are synthesised in the pancreas and secreted into the lumen of the small intestine. Examples of these are Trypsin and chymotrypsin. These are dangerous to cells so stored and packaged into vesicles in an inactive precursor. ]]> 2018-02-09 09:46:38 UTC https://padlet.com/kaityates/PreUDigestion/wish/229948624 Amylase wtas2304 https://padlet.com/kaityates/PreUDigestion/wish/229948981 -The enzyme that hydrolyses Starch to Maltose]]> 2018-02-09 09:47:59 UTC https://padlet.com/kaityates/PreUDigestion/wish/229948981 Duodenum - Charlie and Ayesha https://padlet.com/kaityates/PreUDigestion/wish/229950021 Duodenum: -immovable
- ducts carrying bile + pancreatic secretions enter.
- Almost ALL digestion takes place here due to...
Pancreatic Juice + Bile
- Mucosa of duodenum = few villi, since no absorption
-Submucosa contains glands secreting mucus + sodium hydrogen carbonate.]]> 2018-02-09 09:51:30 UTC https://padlet.com/kaityates/PreUDigestion/wish/229950021 Jejunum + Ileum - Charlie and Ayesha https://padlet.com/kaityates/PreUDigestion/wish/229950484 - Jejunum = 2m long
- Ileum = 4m long
- Site of final digestion + all absorption
- Most lipids absorbed in this organ
- All absorption + most enzymatic digestion on surface of small intestinal epithelial cells
- Internal surface area increased by: large folds of the mucosa, villi + microvilli
- Villi = large structures composed of many cells
- Microvilli = small subcellular structures, formed by folding of plasma membrane of individual cells]]> 2018-02-09 09:53:06 UTC https://padlet.com/kaityates/PreUDigestion/wish/229950484 Large Intestine - Toby and Gemma PART 2 https://padlet.com/kaityates/PreUDigestion/wish/229950541 Appendix
Low power of the appendix typically has a heavy concentration of lymphocytes in both the mucosa and submucosa. Crypts are still here but are less numerous than in the large intestine.

Colon
Contents - Cellulose and fibrous plant materials (lignin), water, dead mucosal cells, bacteria (B vitamins are not absorbed in the large intestine but are present in faeces).
Structure - It is the majority of the length of the large intestine. The epithelium has columnar cells with microvilli brush border, goblet cells are abundant in the colonic epithelium and secret mucus in response to tactile stimuli, alkaline mucus is an important lubricant that protects the epithelium and binds the dehydrated ingest to from faeces.
Function - Water and mineral salts are absorbed (water is absorbed in response to osmosis gradient). The colonic epithelium is more efficient at absorbing water than the small intestine, sodium absorption in the colon is enhanced by the hormone aldosterone. Chloride is absorbed by exchange with bicarbonate. materials normally remain in the colon for 12-14 hours. ]]> 2018-02-09 09:53:14 UTC https://padlet.com/kaityates/PreUDigestion/wish/229950541 https://padlet.com/kaityates/PreUDigestion/wish/229952604 2018-02-09 10:00:14 UTC https://padlet.com/kaityates/PreUDigestion/wish/229952604 Pancreatic Lipase wtas2304 https://padlet.com/kaityates/PreUDigestion/wish/229952707 -A Triglyceride molecule cannot be directly absorbed across the intestinal mucosa; RATHER it must first be digested into a 2-monogyceride and two free fatty acids
- The enzyme that performs hydrolysis is pancreatic lipase]]> 2018-02-09 10:00:39 UTC https://padlet.com/kaityates/PreUDigestion/wish/229952707 Stomach- Katie https://padlet.com/kaityates/PreUDigestion/wish/229952956 2018-02-09 10:01:32 UTC https://padlet.com/kaityates/PreUDigestion/wish/229952956 https://padlet.com/kaityates/PreUDigestion/wish/229953510 🤬 : controlled by 2 sphincter: Inner (smooth muscle, involuntary control) Outer (Straightened muscle, Voluntary control). Normal faeces is 75%water 25% solid (bulk of solids are bacteria and undigested organic matter and fibres. ]]> 2018-02-09 10:03:46 UTC https://padlet.com/kaityates/PreUDigestion/wish/229953510 Four Layers of Alimentary Canal raineye1 https://padlet.com/kaityates/PreUDigestion/wish/229953603 2018-02-09 10:04:04 UTC https://padlet.com/kaityates/PreUDigestion/wish/229953603 Submucosa raineye1 https://padlet.com/kaityates/PreUDigestion/wish/229954085 Definition: The layer of areolar connective tissue lying beneath a mucous membrane.
Structure: Moderately dense connective tissue. Contains blood and lymphathic vessels, lymph nodules and nerve fibres.Contains elastic fibres; allow stomach to regain shape.
Has good blood supply to tissues of the gut wall.]]> 2018-02-09 10:06:11 UTC https://padlet.com/kaityates/PreUDigestion/wish/229954085 Inside the Villus - Charlie and Ayesha https://padlet.com/kaityates/PreUDigestion/wish/229954235 - Nutrients, including amino acids + sugars, enter body across epithelium covering small intestinal villi
- Each villus contains: capillary bed + blunt-ended lymphatic vessel ("Central lacteal")
- Most molecules diffuse into a capillary network
- Some molecules transported into the lymphatic vessel]]> 2018-02-09 10:06:48 UTC https://padlet.com/kaityates/PreUDigestion/wish/229954235 Bicarbonate and water lewisa26 https://padlet.com/kaityates/PreUDigestion/wish/229954580 Epithelial cells in pancreatic ducts are the source of the bicarbonate and water secreted by the pancreas.]]> 2018-02-09 10:08:03 UTC https://padlet.com/kaityates/PreUDigestion/wish/229954580