1. Arrange the following sequence on the basis of their location from midbrain:
Spinal cord, Pons,and Medulla
2. Ranveer rides a bicycle maintaing posture and body equilibrium. Identify the part of brain which controls this activity.
3. Upon adrenalin movement along with blood stream, the blood supply to which two pody parts is reduced?
4. What could be the possible disadvantage if reflex action were controlled by the brain?
5. A Doctor advised a patient to take less sugar in her diet. Which disease is she suffering from?Which body organ and connective tissue is related with it.
6. A particular hormone requires iodine for its synthesis. Name the endocrine gland which secretes this hormone and states it's location in the human body.
7. An element of halogen family is compulsorily added to common salt in small quantity. Identify the element. Also name the disease caused by it's deficiency and write one symptom of this disease.
8. How do the germ cells differ from each other in complex living organisms.
9. Write about the post fertilisation stages in plants.
10. Which part of of the seed form root and shoot?
11. Explain why:
a). When air is taken in & ket out during breathing, the lungs always contain a residual volume of air.
b). Herbivores need a longer small intestine whereas carnivores have a shorter small intestine.
12. Why is it necessary to separate oxygenated and deoxygenated blood into mammals and birds?
13.Distinguish betweenthe movement of leaves of the sensitive plants and movement of shoot towards light.
14.In which form does the wastes are excreted out through human body by kidney.
15. If harmful chemicals enters the food chain comprising cat, mice,and plants. which of these organism is likely to have the maximum conc. of harmful chemicals in iy's body.
Wednesday, February 4, 2009
Sunday, February 1, 2009
Gall Bladder
GALL BLADDER
What is the Gallbladder?
The gallbladder is a pear-shaped organ that can accomodate upto 60 ml of bile (or "gall") until the body needs it for digestion.The gallbladder is about four inches long and is attached to the liver by tiny bile ducts. .
The gallbladder stores about 50 ml of bile, which is made by the liver,which is released when food containing fat enters the digestive tract, stimulating the secretion of cholecystokinin (CCK).
The bile, produced in the liver, emulsifies fats and neutralizes acids in partly digested food.After being stored in the gallbladder the bile becomes more concentrated than when it left the liver, increasing its potency and intensifying its effect on fats. Most digestion occurs in the duodenum.
What are Gallstones?
Gallstones, which are calcified chunks of cholesterol and bilirubin, are formed when the gallbladder doesn’t empty properly, creating a stagnant environment. They can be painful, especially if they pass out through or get stuck in the bile ducts. However, a person could have gallbladder problems even before stones form.Stones, especially the larger ones, can irritate the lining of the gallbladder and cause acute infection. In this case, urgent medical care is needed, including antibiotics. Gallstones can be easily seen with an ultrasound
Removal of the Gallbladder?
In some cases, the gallbladder must be removed. The surgery to remove the gallbladder is called a cholecystectomy. In a cholecystectomy, the gallbladder is removed through a 5- to 8-inch long cut in your abdomen.Once the gallbladder is removed, bile is delivered directly from the liver ducts to the upper part of the intestine.
Complications from Gallbladder removal?
Complications are rare. When complications occur, they may be in the form of: bleeding, infection and injury to the duct (tube) that carries bile from your gallbladder to your stomach.Some patients also experience diarrhea. The cause of diarrhea after gallbladder removal isn't clear
Gall Bladder treatment using BeetFresh juice of beets, and the juices of carrot and cucumber in quantities of 100 ml each, are one of the finest cleansers of the gall-bladder. This combined juice has proved beneficial in the treatment of all disorders related to this organ, and should be taken twice daily.
Gall Bladder Disorder treatment using Pear
The pear is another excellent remedy for gall-bladder disorders. The fruit or its juice should he taken liberally by the patient with beneficial results. It exercises a special healing effect on all gall-bladder disorders, including gallstones.
Gall Bladder treatment using Chicory
The flowers, seeds, and roots of chicory or the endive plant are considered valuable in gall-bladder disorders. A decoction of about 30-60 ml of the flowers, seeds, or roots can be used three times daily with beneficial results in the treatment of these disorders. Endive or chicory juice in almost any combination promotes the secretion of bile and is, therefore, very good for both liver and gall-bladder dysfunctions.
Gall Bladder treatment using Dandelion
Dandelion has a beneficial effect on the gall bladder. About 125 ml each of the juices of dandelion and watercress should be taken twice daily. Combined with a vegetarian diet, without much sugar and starch, these juices help to make the gall¬bladder normal.
Gall Bladder treatment using Olive and Sunflower Oil
An oil cure has been advocated by some nature cure practitioners for the removal of gallstones. Raw, natural, unrefined vegetable oils of olive or sunflower are used. The procedure is to take 30 ml of vegetable oil, preferably olive oil, first thing in the morning and follow it immediately with 120 ml of grapefruit juice or lemon juice. This treatment should be taken every morning for several days, even weeks, if necessary.
posted by poonam ahuja @ 10:18 PM 0 Comments
HOTS & ASSIGNMENT
HOTS (HIGH ORDER THINKING SKILL QUESTIONS)
1. A diagnostyic test for diabetes demands the checking of blood sugar level with the empty stomach and one hr after taking meal. Why?
2. Blood sugar level of a normal person rises after taking a meal-
.i)Why does this happen?
ii) Which hormone regulates this increased level of blood sugar?
iii)Name the source gland of this hormone.
3. Draw a neat diagram of Human brain& label the following parts:
i) Bony box
ii) Area controlling salivation and blood pressure
iii) Part controlling sensory information
iv) Endocrine gland regulating growth and development of the body.
4. During an emergency condition ,capacity of an individual increases to work for hrs..
i) Which hormone is responsible for it
ii) name the source gland of this hormone.
5. Name the chamber of Human heart that:
i) pumps deoxygenated blood to the lungs.
ii)Has thickest muscular walls
6. Even the smell of your favourite dish starts watering of your mouth even though you are concentrating in your studies
. i)What makes this watering of mouth. Which part of the nervous System is responsible forit?
ii) Draw the flow chart of it.
7. A man with blood grp 'A' marries awoman with blood grp 'O'.Their son has blood grp'o' and daughter has blood grp 'A'
i) What is the probable genotype of man and woman.
ii) Specify the expression of the genotype of son and daughter.
8. Where is the protein digesting enzyme 'pepsin' is released and how is it not able to act on stomach's wall.
9. What protects us from the germs that mange to enter in our body along with food.
10. Food always move down even if a person is lying down on the floor. How does it happen?
11. Food in plants is transported from leaves to various parts;
i) In which form food is translocated?
ii) How transport of food is different from transport of water & minerals?
iii) How is osmotic pressure raised in phloem and how does it affect the process of translocation?
12. With the help of flow chart explain the mechanism of transport of food from the place of production to the site of storage.
13. Name the gland that helps in the digestion of food.
14. List four special anatomical/structural features of a leaf that makes it suitable photosynthesic organ
15. Rate of breathing in aquatic organisms is faster than terestrrial organisms. Give reason.
posted by poonam ahuja @ 9:01 PM 0 Comments
1. A diagnostyic test for diabetes demands the checking of blood sugar level with the empty stomach and one hr after taking meal. Why?
2. Blood sugar level of a normal person rises after taking a meal-
.i)Why does this happen?
ii) Which hormone regulates this increased level of blood sugar?
iii)Name the source gland of this hormone.
3. Draw a neat diagram of Human brain& label the following parts:
i) Bony box
ii) Area controlling salivation and blood pressure
iii) Part controlling sensory information
iv) Endocrine gland regulating growth and development of the body.
4. During an emergency condition ,capacity of an individual increases to work for hrs..
i) Which hormone is responsible for it
ii) name the source gland of this hormone.
5. Name the chamber of Human heart that:
i) pumps deoxygenated blood to the lungs.
ii)Has thickest muscular walls
6. Even the smell of your favourite dish starts watering of your mouth even though you are concentrating in your studies
. i)What makes this watering of mouth. Which part of the nervous System is responsible forit?
ii) Draw the flow chart of it.
7. A man with blood grp 'A' marries awoman with blood grp 'O'.Their son has blood grp'o' and daughter has blood grp 'A'
i) What is the probable genotype of man and woman.
ii) Specify the expression of the genotype of son and daughter.
8. Where is the protein digesting enzyme 'pepsin' is released and how is it not able to act on stomach's wall.
9. What protects us from the germs that mange to enter in our body along with food.
10. Food always move down even if a person is lying down on the floor. How does it happen?
11. Food in plants is transported from leaves to various parts;
i) In which form food is translocated?
ii) How transport of food is different from transport of water & minerals?
iii) How is osmotic pressure raised in phloem and how does it affect the process of translocation?
12. With the help of flow chart explain the mechanism of transport of food from the place of production to the site of storage.
13. Name the gland that helps in the digestion of food.
14. List four special anatomical/structural features of a leaf that makes it suitable photosynthesic organ
15. Rate of breathing in aquatic organisms is faster than terestrrial organisms. Give reason.
posted by poonam ahuja @ 9:01 PM 0 Comments
- ASSIGNMENT
CONTROL AND COORDINATION (ANIMALS)
{NERVOUS SYSYTEM}
1.Name the part of brain in which hypothalamus is located?2.Which part of brain is responsible
for precision of voluntary action?
3. Arrange the following in sequence on the basis of their location from mid brain?
spinal cord, pons, &medulla
4. What is synapse?
5. Ram rides a bicycle maintaining posture & body equilibrium. Identify the parts of brain which controls this activity?6. What is the impact of nervous electrical impuse on muscle protein?
7. Which part of the brain is concerned with memory & thinking?
8. Why is salivation considered to be an involuntary action?
9.How is brain protected from shocks & injuries?
10. Name the most important organ related to control & coordination our activites?
11. Gustatory & olfactory receptors related to which sensation?
12. Define reflex action?
13. Name the neuron that links motor & sensory neuron?
14. Write the components of peripheral nervous system?
15. Name the place of origin of cranial &spinal nervous?
16. Which two organs receive the information from all body parts and integrate it?
17.Which nutrient of food is associated with muscular action?
18. What could be the possible disadvantage if reflex action were controlled by the brain?
19. Which part of the brain you associate with smell of delicious food?
20. Enlist the function of medulla?
21. How is spinal cord related to the efficiency of reflex arc?
22. What are the two limitation of electrical impulse?
24. Draw a well labeled diagram of human brain?
25. Draw a well labeled diagram of neuro muscular junction?
26. Elucidate the nerve impulse mechanism?
27.Define a reflex arc. Draw its labeled diagram?
28. Write major function of three parts of brain?
29. Briefly describe the three part of neuron?
30.Distinguish b/w sensory, motor and mixed nerve?
31. Trace the event occurring in reflex action. What is its importance?
32. Draw a labeled diagram of brain?
33. Write the function of any one part of brain?
34. Define synapse?
35. What is function of medulla oblongata?
36. Name the largest & second largest part of brain?
37. Which organ constitutes the C.N.S?
38. What is the function of cerebrospinal fluid & where is it found?
39. Which part of brain is concerned memory will and power?
40. Distinguish b/w cranial and spinal nerve?
41. What is the major division of fore brain?
42. List important function of nervous system?
43. Give an account of structure of hind brain in man?
44. Name the part of brain which is center of perception of visual images?
45. Name the receptor of light, smell and taste in animals?
46. State and elaborate the two limitation / constraints in transmission of electrical impulses of nerves?
47. What are the three major component of human brain?
CHEMICAL CO-ORDINATION IN ANIMALS
ENDOCRINE SYSTEM
1. What are receptors? What are their basic functions?
2. What is the effect of adrenaline on the rate of beating of heart?
3. Upon adrenaline movement along with blood stream the blood supply to which two body parts is reduced?
4. How our body growth is associated with thyroxin?
5. Where is the adrenal gland in our body located?
6. How is iodine important for biochemical reactions inside the body?
7. A doctor advise a patient to take less sugar in her diet. Which disease is she suffering from? Which body organ and connective tissue is related with it?
8. Describe the feedback mechanism.
9. Enlist one advantage and one limitation of chemical communication.
10. Elaborate the body’s response to adrenaline secretion into the blood.
11. An element of halogen family is compulsorily added to common salt in small quantity. Identify the element. Also name the disease caused by its deficiency and write one symptom of this disease.
12. Enlist the hormones secreted by ovary, testes & adrenal gland. Write one function of each hormone.
13. Name the hormones which maintains chelcium level of blood.
14. ‘Insulin is known as anabolic hormone? Explain.
15. Name the hormone secreted by thyroid, parathyroid & pancreas.
16. Name two endocrine glands present in neck region.
17. Which hormone is called the emergency hormone?
18. Name and endocrine gland that is associated with digestive system?
19. Why are some patients of diabetes treated by giving injections of insulin?
20. Name one hormone secreted by pituitary gland. What is its function? What happens if it is not produced in sufficient quantity?
CONTROL AND CO-ORDINATION IN PLANTS
1. Name two plant hormones that help in stem growth?
2. Which of the two is slower – growth dependent or growth independent movement in plants?
3. Where is auxin synthesized?
4. Movement of which chemical compound help plants in changing shape?
5. How plants communicate the information of touch as stimulus as in touch me not plant?
6. Tendril encircles or coils around the object in contact with it. Elaborate.
7. Define plant hormone. Write the important functions of the following:-
Auxin, abscissic acid, gibberellins and cytokinin.
8. Name anyone a growth regulator each that promote and inhibits growth?
9. Distinguish between nastic & tropic movements.
10. Give one example of chemotropism.
11. Describe any two tropic movements with suitable examples.
12. How does control and co-ordition in plant take place?
13. Which hormone is produce in the tip of the stem?
14. What are the function of plant hormones & how do they show their actions?
15. Name the hormone, the concentration of which is higher in the areas of rapid cell division.
16. Name the hormone responsible of wilting and falling of leaves.
17. Design & experiment to demonstrate hydrotropism.
18. How is the movement of leaves of sensitive plants different from the movement of shoot towards light.
19. Describe an example of immediate plant response to a stimulus.
Thursday, May 1, 2008
Holidays Home Work X, Biology
- Revise the entire syllabus completed till 17 May 08.
- Attempt all the questions of assignments (already given) of Topics NUTRITION, RESPIRATION and TRANSPORT OF SUBSTANCE.
- Complete all the experiments done so far in your Practical File.
- Visit the site http://ahujapoonam2.blogspot.com and go through the related content and give your comments.
- Practice the labeled diagrams of the following:
a) Closed and Opened stomata
b) Human Digestive System
c) Human Respiratory System
d) Functional Unit of Human Excretory System
e) Cross Section of the Human Heart
f) Schematic representation of transport and exchange of oxygen and carbon dioxide
g) Human Excretory System
Thursday, March 6, 2008
molecular phylogeny
MOLECULAR PHYLOGENY
Every living organism contains DNA, RNA, and proteins.
Closely related organisms generally have a high degree of agreement in the molecular structure of these substances, while the molecules of organisms distantly related usually show a pattern of dissimilarity.
Molecular phylogeny uses such data to build a "relationship tree" that shows the probable evolution of various organisms.
Molecular phylogenetics attempts to determine the rates and patterns of change occurring in DNA and proteins and to reconstruct the evolutionary history of genes and organisms.
Two general approaches may be taken to obtain this information.
In the first approach, scientists use DNA to study the evolution of an organism.
In the second approach, different organisms are used to study the evolution of DNA.
Whatever the approach, the general goal is to infer process from pattern: the processes of organismal evolution deduced from patterns of DNA variation and processes of molecular evolution inferred from the patterns of variations in the DNA itself.
Saturday, March 1, 2008
Digestion in Humans
Digestive System
Digestion is the chemical breakdown of large food molecules into smaller molecules that can be used by cells. The breakdown occurs when certain specific enzymes are mixed with the food.
Enzymes involved in Digestion
The process of digestion produces glucose, amino acids, glycerol, and fatty acids.
The energy in glucose is used to produce ATP via the reactions of glycolysis, cellular respiration, and the electron transport system .
The body uses amino acids to construct proteins.
Glycerol and fatty acids can be converted to pyruvate and Acetyl CoA and then enter cellular respiration.
Mouth
Chewing breaks food into smaller particles so that chemical digestion can occur faster.
Enzymes
Salivary amylase breaks starch (a polysaccharide) down to maltose (a disaccharide).
Bicarbonate ions in saliva act as buffers, maintaining a pH between 6.5 and 7.5.
Mucins (mucous) lubricate and help hold chewed food together in a clump called a bolus.
The tongue contains chemical receptors in structures called taste buds.
The tongue is muscular and can move food. It pushes food to back where it is swallowed.
Pharynx
The respiratory and digestive passages meet in the pharynx.
They separate posterior to the pharynx to form the esophagus (leads to the stomach) and trachea (leads to the lungs).
Swallowing is accomplished by reflexes that close the opening to the trachea.
When swallowing, the epiglottis covers the trachea to prevent food from entering.
In the mouth, food is mixed with saliva and formed into a bolus.
Peristalsis refers to rhythmic contractions that move food in the gut. Peristalsis in the esophagus moves food from the mouth to the stomach.
Stomach
The stomach stores up to 2 liters of food.
Gastric glands within the stomach produce secretions called gastric juice.
The muscular walls of the stomach contract vigorously to mix food with gastric juice, producing a mixture called chyme.
Gastric juice
Pepsinogen is converted to pepsin, which digests proteins.
Pepsinogen production is stimulated by the presence of gastrin in the blood .
HCl
Hydrochloric acid (HCl) converts pepsinogen to pepsin which breaks down proteins to peptides. HCl maintains a pH in the stomach of approximately 2.0.
It also dissolves food and kills microorganisms.
Mucous protects the stomach from HCl and pepsin.
Secretion of Gastric Juice
Seeing, smelling, tasting, or thinking about food can result in the secretion of gastric juice.
Gastrin is a hormone that stimulates the stomach to secrete gastric juice.
An ulcer is an irritation due to gastric juice penetrating the mucous lining of the stomach or duodenum.
It is believed that ulcers are caused by the bacterium Helicobacter pylori, which, can thrive in the acid environment of the stomach. The presence of the bacteria on portions of the stomach lining prevents it from secreting mucous, making it susceptible to the digestive action of pepsin.
Duodenum
The duodenum is the first part of the small intestine.
Chyme enters through a sphincter.
It enters in tiny spurts.
At this point, proteins and carbohydrates are only partially digested and lipid digestion has not begun.
Pancreas
The pancreas acts as an exocrine gland by producing pancreatic juice which empties into the small intestine via a duct.
The pancreas also acts as an endocrine gland to produce insulin.
Digestion is the chemical breakdown of large food molecules into smaller molecules that can be used by cells. The breakdown occurs when certain specific enzymes are mixed with the food.
Enzymes involved in Digestion
The process of digestion produces glucose, amino acids, glycerol, and fatty acids.
The energy in glucose is used to produce ATP via the reactions of glycolysis, cellular respiration, and the electron transport system .
The body uses amino acids to construct proteins.
Glycerol and fatty acids can be converted to pyruvate and Acetyl CoA and then enter cellular respiration.
Mouth
Chewing breaks food into smaller particles so that chemical digestion can occur faster.
Enzymes
Salivary amylase breaks starch (a polysaccharide) down to maltose (a disaccharide).
Bicarbonate ions in saliva act as buffers, maintaining a pH between 6.5 and 7.5.
Mucins (mucous) lubricate and help hold chewed food together in a clump called a bolus.
The tongue contains chemical receptors in structures called taste buds.
The tongue is muscular and can move food. It pushes food to back where it is swallowed.
Pharynx
The respiratory and digestive passages meet in the pharynx.
They separate posterior to the pharynx to form the esophagus (leads to the stomach) and trachea (leads to the lungs).
Swallowing is accomplished by reflexes that close the opening to the trachea.
When swallowing, the epiglottis covers the trachea to prevent food from entering.
In the mouth, food is mixed with saliva and formed into a bolus.
Peristalsis refers to rhythmic contractions that move food in the gut. Peristalsis in the esophagus moves food from the mouth to the stomach.
Stomach
The stomach stores up to 2 liters of food.
Gastric glands within the stomach produce secretions called gastric juice.
The muscular walls of the stomach contract vigorously to mix food with gastric juice, producing a mixture called chyme.
Gastric juice
Pepsinogen is converted to pepsin, which digests proteins.
Pepsinogen production is stimulated by the presence of gastrin in the blood .
HCl
Hydrochloric acid (HCl) converts pepsinogen to pepsin which breaks down proteins to peptides. HCl maintains a pH in the stomach of approximately 2.0.
It also dissolves food and kills microorganisms.
Mucous protects the stomach from HCl and pepsin.
Secretion of Gastric Juice
Seeing, smelling, tasting, or thinking about food can result in the secretion of gastric juice.
Gastrin is a hormone that stimulates the stomach to secrete gastric juice.
An ulcer is an irritation due to gastric juice penetrating the mucous lining of the stomach or duodenum.
It is believed that ulcers are caused by the bacterium Helicobacter pylori, which, can thrive in the acid environment of the stomach. The presence of the bacteria on portions of the stomach lining prevents it from secreting mucous, making it susceptible to the digestive action of pepsin.
Duodenum
The duodenum is the first part of the small intestine.
Chyme enters through a sphincter.
It enters in tiny spurts.
At this point, proteins and carbohydrates are only partially digested and lipid digestion has not begun.
Pancreas
The pancreas acts as an exocrine gland by producing pancreatic juice which empties into the small intestine via a duct.
The pancreas also acts as an endocrine gland to produce insulin.
Pancreatic Juice
Pancreatic juice contains sodium bicarbonate which neutralizes the acidic material from the stomach.
Pancreatic amylase digests starch to maltose.
Trypsin and Chymotrypsin digest proteins to peptides.
Lipase digests fats to glycerol and fatty acids.
Liver
The liver produces bile which is stored in gallbladder and sent to the duodenum through a duct.
Bile emulsifies fats (separates it into small droplets) so they can mix with water and be acted upon by enzymes.
Other Functions of the Liver
1.The liver detoxifies blood from intestines that it receives via the hepatic portal vein.
2. The liver stores glucose as glycogen (animal starch) and breaks down glycogen to release glucose as needed.
This storage-release process maintains a constant glucose concentration in the blood (0.1%). If glycogen and glucose run short, proteins can be converted to glucose.
3. It produces blood proteins.
4. It destroys old red blood cells and converts hemoglobin from these cells to bilirubin and biliverdin which are components of bile.
5. Ammonia produced by the digestion of proteins is converted to a less toxic compound (urea) by the liver.
Hormones Involved in Digestion
The hormones listed below, like all hormones, reach their target cells by the circulatory system.
Gastrin
The presence of food in the stomach stimulates stretch receptors which relay this information to the medulla oblongata. The medulla stimulates endocrine cells in the stomach to secrete the hormone gastrin into the circulatory system. Gastrin stimulates the stomach to secrete gastric juice.
Secretin
Secretin is produced by cells of the duodenum.
It’s production is stimulated by acid chyme from stomach.
It stimulates the pancreas to produce sodium bicarbonate, which neutralizes the acidic chyme. It also stimulates the liver to secrete bile.
CCK (cholecystokinin)
CCK production is stimulated by the presence of food in the duodenum.
It stimulates the gallbladder to release bile and the pancreas to produce pancreatic enzymes.
GIP (Gastric Inhibitory Peptide)
Food in the duodenum stimulates certain endocrine cells to produce GIP.
It has the opposite effects of gastrin; it inhibits gastric glands in the stomach and it inhibits the mixing and churning movement of stomach muscles. This slows the rate of stomach emptying when the duodenum contains food.
Small Intestine
The small intestine is approximately 3 m long.
Like the stomach, it contains numerous ridges and furrows. In addition, there are numerous projections called villi that function to increase the surface area of the intestine. Individual villus cells have microvilli which greatly increase absorptive surface area.
The total absorptive surface area is equivalent to 500 or 600 square meters.
Each villus contains blood vessels and a lacteal (lymph vessel).
Peptidases and maltase are embedded within the plasma membrane of the microvilli.
Peptidases complete the digestion of peptides to amino acids.
Maltase completes the digestion of disaccharides.
Absorption
Absorption is an important function of the small intestine.
Active transport moves glucose and amino acids into the intestinal cells, then out where they are picked up by capillaries.
Glycerol and fatty acids produced by the digestion of fat enter the villi by diffusion and are reassembled into fat (triglycerides). They combine with proteins and are expelled by exocytosis. They move into the lacteals for transport via the lymphatic system.
Large Intestine
The large intestine is also called the colon.
It receives approximately 10 liters of water per day. 1.5 liters is from food and 8.5 liters is from secretions into the gut. 95% of this water is reabsorbed.
The large intestine also absorbs sodium and other ions but it excretes other metallic ions into the wastes.
If water is not absorbed, diarrhea can result, causing dehydration and ion loss.
It absorbs vitamin K produced by colon bacteria.
The last 20 cm of the large intestine is the rectum.
Feces is composed of approximately 75% water and 25% solids. One-third of the solids is intestinal bacteria, 2/3’s is undigested materials.
The cecum is a pouch at the junction of the small intestine and large intestine. In herbivorous mammals, it is large and houses bacteria capable of digesting cellulose. In human ancestors, the cecum was larger but has been reduced by evolutionary change to form the appendix.
Polyps
Polyps are small growths in the epithelial lining of the colon.
They can be benign or cancerous and can be removed individually.
A low-fat, high-fiber diet promotes regularity and is recommended as a protection against colon cancer.
Appendix
The appendix is attached to cecum.
Appendicitis is an infection. The appendix may swell and burst, leading to peritonitis (infection of the abdominal lining).
Summary of Digestive Enzymes
The digestive enzymes in the table below are summarized according to type of food that they digest.
role of liver in digestion
Liver:
An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.
Bile is a complex fluid containing water, electrolytes and a battery of organic molecules including bile acids, cholesterol, phospholipids and bilirubin that flows through the biliary tract into the small intestine.
Bile is a complex fluid containing water, electrolytes and a battery of organic molecules including bile acids, cholesterol, phospholipids and bilirubin that flows through the biliary tract into the small intestine.
There are two fundamentally important functions of bile in all species:
Bile contains bile acids, which are critical for digestion and absorption of fats and fat-soluble vitamins in the small intestine.
Many waste products including bilirubin, are eliminated from the body by secretion into bile and elimination in feces.
Adult humans produce 400 to 800 ml of bile daily, and other animals proportionately similar amounts.
In species with a gallbladder (man and most domestic animals except horses and rats), further modification of bile occurs in that organ. The gall bladder stores and concentrates bile during the fasting state. Typically, bile is concentrated five-fold in the gall bladder by absorption of water and small electrolytes - virtually all of the the organic molecules are retained.
Role of Bile Acids in Fat Digestion and Absorption
Emulsification of lipid aggregates: Bile acids have detergent action on particles of dietary fat which causes fat globules to break down or be emulsified into minute, microscopic droplets. Emulsification is not digestion per se, but is of importance because it greatly increases the surface area of fat, making it available for digestion by lipases, which cannot access the inside of lipid droplets.
Solubilization and transport of lipids in an aqueous environment: Bile acids are lipid carriers and are able to solubilize many lipids by forming micelles - aggregates of lipids such as fatty acids, cholesterol and monoglycerides - that remain suspended in water. Bile acids are also critical for transport and absorption of the fat-soluble vitamins.
Bile contains bile acids, which are critical for digestion and absorption of fats and fat-soluble vitamins in the small intestine.
Many waste products including bilirubin, are eliminated from the body by secretion into bile and elimination in feces.
Adult humans produce 400 to 800 ml of bile daily, and other animals proportionately similar amounts.
In species with a gallbladder (man and most domestic animals except horses and rats), further modification of bile occurs in that organ. The gall bladder stores and concentrates bile during the fasting state. Typically, bile is concentrated five-fold in the gall bladder by absorption of water and small electrolytes - virtually all of the the organic molecules are retained.
Role of Bile Acids in Fat Digestion and Absorption
Emulsification of lipid aggregates: Bile acids have detergent action on particles of dietary fat which causes fat globules to break down or be emulsified into minute, microscopic droplets. Emulsification is not digestion per se, but is of importance because it greatly increases the surface area of fat, making it available for digestion by lipases, which cannot access the inside of lipid droplets.
Solubilization and transport of lipids in an aqueous environment: Bile acids are lipid carriers and are able to solubilize many lipids by forming micelles - aggregates of lipids such as fatty acids, cholesterol and monoglycerides - that remain suspended in water. Bile acids are also critical for transport and absorption of the fat-soluble vitamins.
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