Long Answer Question 2 Flashcards
1
Q
- How do digestive enzymes function to assist absorption of nutrients in the small intestine?
- Include the function of salivary amylase and pepsin. What enzymes are present in pancreatic juice and intestinal juice?
- What do the digestive enzymes break food particles into?
A
- Digestive enzymes speed up the chemical reactions that involve digestion of the components of food. They are digested to form appropriate nutrient molecules, allowing them to be absorbed into the circulatory/lymphatic system
- Salivary amylase begins digestion of starch in the mouth and pepsin begins digestion of protein in the stomach. Pancreatic amylase, trypsin, nuclease, and lipase are all present in pancreatic juices that enter the small intestine at the duodenum. Maltase, peptidases, and nucleosidases are all secreted from the small intestines in intestinal juice.
- The digestive enzymes will break the food particles up until they resemble glycerol and fatty acids; base, sugar, and phosphate; amino acids; and glucose. These nutrients can be absorbed by the small intestine wall and enter the vessels there
2
Q
Why is water important for digestive enzymes?
A
Water is a huge part of digestive enzymes because the digestion process requires a hydrolysis reaction - a reaction to degrade polymers where the components of water are added
3
Q
- How is the condition of the small intestine optimal for absorption of nutrients? (2)
A
- The basic condition in the small intestine is optimal for digestive enzymes that are present from pancreatic juice or from secretions of the intestinal wall.
- The surface area is especially large for effective absorption of nutrients. The walls contain fingerlike projections called villi. Each villus has an outer layer of columnar epithelial cells that have thousands of microscopic extensions called microvilli. Microvilli greatly increase the surface area of the villus for absorption of nutrients.
4
Q
- What vessels do each villus carry?
- Specify which nutrients enter each vessel. (2)
A
- Each villus also contains blood capillaries and small lymphatic capillary, called a lacteal.
- Glycerol and fatty acids (digested from fats) enter the epithelial cells of villi where they are joined and packaged with lipoprotein droplets that enter the lacteal
- Sugars and amino acids directly enter blood capillaries of villus
5
Q
How does the lymphatic system connect to the circulatory system? (2)
A
- Villi in the small intestine contain lacteals. Lacteals are a part of the lymphatic system. The lymphatic system is adjunct to the cardiovascular system; so lymphatic vessels carry a fluid called lymph to the cardiovascular veins
- Lymphatic capillaries join to form lymphatic vessels that merge before entering one of two ducts: the thoracic duct or the right lymphatic duct. Thoracic duct drains lymph into the left subclavian vein and the right lymphatic duct drains lymph into the right subclavian vein
6
Q
State the structure of lymphatic vessels that helps it transport lymph.
A
- skeletal muscles: Movement of lymph is largely dependent on skeletal muscle contraction
- one way valves: lymph forced through vessels from muscular contraction is prevented from flowing backwards by one-way valves
7
Q
- What is the fluid in lymphatic system called?
- State its composition (6) and where they come from
A
- Fluid in lymphatic capillaries, called lymph, is mostly water, providing fluidity to the lymph.
- Lymph is composed of excess tissue fluid containing solutes (ie. nutrients, electrolytes, and oxygen) derived from plasma and cellular products (ie. hormones, enzymes, and wastes) secreted by cells
8
Q
How does blood assist the digestive system and circulatory system?
A
Blood transfers nutrients, wastes, and hormones
9
Q
- Why is water important in blood?
- How does water in blood connect to the digestive system?
A
- Plasma makes up about 55% of blood and 90-92% of plasma is water. Water in blood functions to maintain blood volume and assist in transportation of molecules (acts as a solvent for molecules)
- Water is absorbed from intestines of digestive tract!
10
Q
What controls the movement of fluid through the capillary wall and how do they do so? (2)
A
Two forces primarily control movement of fluid through capillary wall:
- osmotic pressure, created by salts and plasma proteins, which tends to cause water to move from tissue fluid to blood
- blood pressure, which tends to cause water to move in opposite direction
11
Q
- What occurs at the arterial end of a blood capillary?
- What occurs at the venous end of a blood capillary?
A
- At arterial end of blood capillary: blood pressure is higher than osmotic pressure so water exits at capillary at this end as net pressure is out
- At venous end osmotic pressure is greater than blood pressure and water tends to move into capillary
12
Q
- What happens at the midpoint of the capillary? (2)
- Where are the nutrients from digestive tract after the capillary-tissue exchange?
A
- Midway along capillary, where blood pressure is lower, the 2 forces cancel each other out causing no net movement of water
- Solutes now diffuse according to concentration gradient: nutrients (glucose and amino acids from digestive tract) and oxygen diffuse out of capillary, and wastes (carbon dioxide) diffuse into capillary
- Nutrients from digestive tract are now in tissue fluid (the fluid between the cells) where they can supply the cells and keep the human body performing well
13
Q
- Where are capillaries found?
- How is this important and relevant for nutrients coming from the digestive tract?
A
- Capillaries are found in nearly all regions of the body and serve the cells through exchange of substances across their thin walls
- Nutrients from the digestive tract in blood will travel to cells all over the body and supply them for their needs and processes
14
Q
How does the circulatory system vessels aid the liver in its general function? (2)
A
- Capillaries that occur in the villi of small intestine pass into venules that join to form the hepatic portal vein
- Vein carries blood with nutrients from intestines to set of capillaries in the liver, an organ that monitors the makeup of blood
15
Q
How does the liver function to monitor the makeup of blood? (5)
A
- Detoxifies blood by removing and metabolizing poisonous substances
- Makes many plasma proteins, such as albumins and fibrinogen, from amino acids
- Stores glucose as glycogen after a meal, and breaks down glycogen to glucose to maintain glucose concentration of blood between eating periods
- Removes bilirubin, a breakdown product of hemoglobin, from the blood
- Helps regulate blood cholesterol level, converting some to bile salts
