Animal Forms and Functions- [Digestive System, Nervous System, The Eyes/ The Ears Flashcards
The Digestive System
*Intracellular
*Gastrovascular cavity
*extracellular
*
The Digestive System is the chemical breakdown of food into smaller molecules.
- INTRACELLULAR - when a lysosome containing digestive enzymes merges with a food vacuole.
- Food is first digested in a GASTROVASCULAR cavity by EXTRA CELLULAR digestion and then absorbed by individual cells.
Digestion in Humans: Four groups of molecules encountered:What do they break down? 1. Starches --> 2. Proteins --> 3. Fats ---> 4. Nucleic acids --->`
- Starches –> breaks down to glucose
- Proteins –> breaks down to amino acids
- Fats —> breaks down to fatty acids/glycerol
- Nucleic acids —> breaks down to nucleotides.
Digestion follows a specific series of events
- Mouth
* salivary a-amylase-what does it break down?
- *bolus
Salivary a-amylase breaks down (starch –> maltose), chewing creates BOLUS which is swallowed.
BOLUS - is a mass of food that has been chewed up.
Digestion follows a specific series of events
- Pharnyx(throat)
- Epiglottis
This is where food and air passages cross; the EPIGLOTTIS, flap of tissue, blocks trachea so only solid and liquid enter…
Digestion follows a specific series of events
- Esophagus
- peristalsis
Helps Food move through the esophagus, a tube leading to the stomach, by muscular contractions called PERISTALSIS.
-PERISTALSIS is the involuntary contraction of smooth muscles. It allows the movement of food thru the digestive tract.
Digestion follows a specific series of events
- Stomach
- gastric juice
- Exocrine glands
- Storage- how many liters does it store?
- Mixing - CHYME
The stomach secretes GASTRIC JUICE, a mixture of digestive enzymes and hydrochloric acid (HCL),
Stomach contains EXOCRINE GLANDS.
Storage - Accordionlike folds, allows 2-4 liters of storage.
Mixing - The stomach mixes the food w water & gastric juice to produce a creamy medium called CHYME.
CHYME is liquified food. It is first referred as BOLUS before turning into CHYME.
Digestion follows a specific series of events
- Stomach
- Physical breakdown
- Chemical Breakdown
- pepsin, parietal cells
- Peptic Ulcers - Controlled Release -pyloric sphincter
Physical Breakdown - muscles break down food, HCL denatures proteins & kills bacteria.
Chemical Breakdown - PEPSIN(secreted by Chief cells) Digests proteins; (pepsinogen activated by HCL, which is secreted by PARIETAL CELLS.
PEPTIC ULCERS = caused by failure of mucosal lining to protect stomach. This causes pain.
- Ulcers can be caused by excess stomach acid.
Controlled Release -Movement of chyme into the small intestine is regulated by a valve at the end of the stomach, the PYLORIC SPHINCTER.
Digestion follows a specific series of events 4. Stomach Small intestine *Pyloric SPhincter *duodenum Small Intestines enzymes * PROTEOLYTIC * PROTEASES * PHOSPHATASES
PYLORIC SPHINCTER acts as a barrier b/w stomach and small intestine.
Food goes from stomach to small intestine through the PYLORIC SPHINCTER - the first 25 cm of the small intestine, the DUODENUM, continues the digestion of starches and proteins as well as remaining food types (fats & nucleotides)
The wall of the samll intestine is the source of various enzymes, including PROTEOLYTIC enzymes (or PROTEASES, enzymes that digest proteins, such as AMINOPEPTIDASE), maltase and lactase9for digestion of saccharides), and PHOSPHATASES.
The Digestive System
- Pancreas
- What does it secrete?
- Trypsin, chymotrypsin, lipase, pancreatic amylase
The pancreas produces various enzymes, including TRPSIN and CHYMOTRYPSIN(proteases), LIPASE(digestion of fats), and PANCREATIC AMYLASE (digestion of starch).
The Pancrease secretes bicarbonate.
The Digestive System
- Liver -What does it produce/secretes?
*Gall Bladder
The liver produces bile stored in GALL BLADDER, flows thru bile duct which merges with pancreatic duct.
The Digestive System
-The remainder of the small intestine absorbs the breakdown products of food. IT is characterized by VILLI and MICROVILLI.
Remainder of small intestine (6m) absorbs breakdown products (VILLI and MICROVILLI)
The Digestive System
- Large Intestine(colon)- What does it reabsorbed?
- Feces
* Rectum —> Anus
* Cecum
* Symbiont/Vitamin K
- Feces
- reabsorption of water and salts to form FECES; 1.5m long.
- Feces stored at end of L.I. in the RECTUM —> excreted thru ANUS.
- Herbivores is a large CECUM(cellulose digestion) with the help of bacteria.
- Bacteria is a SYMBIONT in large intestine = main source of VITAMIN K
The Digestive System
Hormones involved in the digestive process
1. Gastrin
Gastrin - a peptide hormone that stimulates secretion of gastric acid(HCL)
The Digestive System
Hormones involved in the digestive process
2. Secretin
*Duodenum
Produced by cells lining DUODENUM when food enters; stimulates pancreas to produce bicarbonate.
The Digestive System
Hormones involved in the digestive process
3. Cholecystokinin(CCK) - what organ is this produced by?
What does it secrete?
*Fats
Produced by S.I. in response to FATS; stimulates gallbladder to contract & release bile and pancreas to release its enzymes.
The Digestive System
Hormones involved in the digestive process
4. Gastric Inhibitory Peptide
A hormone secreted by cells of the intestinal mucosa that blocks the secretion of HCL into the stomach.
Digestion in plants and fungi
- Intracellular digestion-
* *Starch
Plants have no digestive system.
Intracellular Digestion - store primarily STARCH in seeds, stems, and rootsl when nutrients are required, polymers are broken down (into glucose, fatty acid, glycerol, and amino acids) bu enzymatic HYDROLSIS.
Digestion in plants and fungi
- Extracellular digestion
- Fungi
- Venus Flytrap
- Several plants must obtain nutrient from environment
- Fungi - rhizoids of bread mold, secrete enzymes into bread, producing simple digestive products which are then absorbed by diffusion into rhizoid.
Venus Flytrap - enzymes digest trapped fly Still Autotrophic
The Nervous System
- Neuron
- Cell Body
- Dendrite
- Axon
The basic structural unit of the nervous system is a nerve cell, or NEURON. It
- Has 3 parts: Cell Body, Dendrite, Axon
- Cell Body contains nucleus/other organelles
- Dendrites - Receive information and transfer it TO CELL BODY
- Axon - Transfers AWAY from cell body.
The Nervous System
-Glial Cells
Nervous tissue support cells; capable of cellular division.
The Nervous System
-Oligodendrocytes
Produce myelin in CNS; wrap many times around axons.
The Nervous System
- Schwann cells(glial cells)
- Myelin sheaths
* Nodes of Ranvier
* Saluatory conduction
- Myelin sheaths
Produce myelin in PNS.Myelin sheaths act insulators to speed up the impulse. They are separated by NODES OF RANVIER(gaps between Schwann cell). Instead of traveling continuously down axon, action potential jumps from node to node (SALUTATORY CONDUCTION), speeding up impulse