topic 4: water balance
State that homeostasis is the maintenance of a constant internal environment and that body water content and body temperature are both examples of homeostasis
State: Give a specific name, value or other brief answer without explanation or calculation.
State: Give a specific name, value or other brief answer without explanation or calculation.
The human organism consists of cells working together to maintain the organism. While cells may perform different functions, all the cells are quite similar in their metabolic activity. Maintaining a constant internal environment with all that the cells need to survive is necessary for the well-being of individual cells and the well-being of the entire body. Homeostasis is the control of internal conditions, be it temperature, specific blood conditions or other variables within living organisms.
The purpose of homeostasis is to provide a consistent internal environment for proper enzymatic activities. Each process, or reaction, has a desirable peak environment. Influences, such as an external influence, can cause deviation away from this norm level and the body will correct this change – this is called negative feedback.
Negative feedback is the most common type of reaction, because it is only natural to rectify a potential problem, but there is also positive feedback. This is when the body will push itself further away from the normal level.
The purpose of homeostasis is to provide a consistent internal environment for proper enzymatic activities. Each process, or reaction, has a desirable peak environment. Influences, such as an external influence, can cause deviation away from this norm level and the body will correct this change – this is called negative feedback.
Negative feedback is the most common type of reaction, because it is only natural to rectify a potential problem, but there is also positive feedback. This is when the body will push itself further away from the normal level.
Explain how organisms are able to respond to changes in their environment
Explain: Give a detailed account.
Explain: Give a detailed account.
Changes occur in the external environment of all organisms on Earth. Species have changed over thousands of years in a changing environment. Multicellular organisms rely on body systems to function together so all the cells have the right conditions such as, levels of nutrients and oxygen, and also so their toxic wastes are removed. The circulatory, respiratory, digestive, excretory system in humans work together to provide a relatively stable internal environment in cells.
State that the lungs, kidneys and skin are organs of excretion
State: Give a specific name, value or other brief answer without explanation or calculation.
State: Give a specific name, value or other brief answer without explanation or calculation.
The excretory system is a passive biological system that removes excess, unnecessary or dangerous materials from an organism. This process helps maintain the homeostasis within the organism and prevent damage to the cells. It is responsible for the elimination of the waste products of metabolism as well as other liquid and gaseous wastes. As most healthy functioning organs produce metabolic and other wastes, the entire organism depends on the function of the system; however, only the organs specifically for the excretion process are considered a part of the excretory system.
Evaluate the relationship between surface area, volume and surface area to volume ratio in relationship to heat loss
Evaluate: Make an appraisal by weighing up the strengths and limitations.
Evaluate: Make an appraisal by weighing up the strengths and limitations.
image from www.open.edu
Small-bodied animals or plant parts (e.g., leaves) heat up and cool down faster; bigger and/or thicker bodies heat up and cool down slower. Smaller/thinner bodies have a larger surface area to volume ratio. Bodies gain and lose heat out of the surface of their body; more surface area means greater gains and losses. Bodies retain heat within their bodies; more volume means more heat retention. When the surface area is large compared to the volume (small/thin things), heat is gained and lost quickly because there is lots of surface area to gain and lose heat and relatively little volume to retain heat.
Advantages and Disadvantages to being Large:
Advantages and Disadvantages to being Large:
- Heat is gained and lost more slowly so, for example, on a hot summer day, the a large animal may never reach lethal temperatures by the time the sun sets.
- Because heat is lost more slowly, the animal doesn't have to replace lost heat as quickly; therefore, the animal doesn't have to eat as much compared to its body weight (e.g., only has to eat 1/4 its body weight). However, it usually does have to eat more total food than a smaller animal.
- Heat is gained and lost faster so, for example, on a hot summer day, a small leaf (less than about 1 square centimeter) will shed heat as fast as it acquires heat; therefore the leaf will never reach temperatures higher than air temperature (compared to a large, thick leaf that acquires a heat load and can reach very high, lethal temperatures).
- Because heat is lost faster, the animal has to eat faster to replace the lost energy (e.g., very small mammals may eat up to 4 times their body weight each day).
Describe thermoregulation humans in terms of insulation and the role of temperature receptors in the skin, sweating, shivering, vasodilation and vasoconstriction of arterioles
Describe: Give a detailed account or picture of a situation, event, pattern or process.
Describe: Give a detailed account or picture of a situation, event, pattern or process.
Sweating, vasodilaton and vasoconstriction, piloerection, and shivering act together to keep the body temperature within 37 C.
If the body temperature increases, (this can be detected by he hypothalamus) the sweat glands produce greater amounts of sweat. This liquid is secreted onto the surface of the skin. When a liquid is evaporated it turns into a gas, and this change requires energy called the latent heat of vapourisation. When sweat evaporates, the energy is supplied by the bodies heat cooling the body down.
Blood flows through small capillaries within the dermis layer of the skin. Heat radiates to the outside of the skin helping to cool the body down. If the body is too hot small arteries (arterioles) leading to the capillary loops dilate (widen). This increases blood flow to the skins surface and is called vasodilation.
In cold conditions the opposite happens. the arterioles leading the the surface capillary loops constrict ( become narrower) and blood flow to the skin id reduced, so that less heat is lost. This is called vasoconstriction.
In cold conditions the hair erector muscles at the base of the hair on you skin, contract and the hairs are pulled upright. this traps a layer of air next to the skin, and since air is a poor conductor of heat, this acts as insulation.
Shivering also takes place in cold conditions, it is when the muscles relax and contract rapidly. This generates a large amount of heat.
If the body temperature increases, (this can be detected by he hypothalamus) the sweat glands produce greater amounts of sweat. This liquid is secreted onto the surface of the skin. When a liquid is evaporated it turns into a gas, and this change requires energy called the latent heat of vapourisation. When sweat evaporates, the energy is supplied by the bodies heat cooling the body down.
Blood flows through small capillaries within the dermis layer of the skin. Heat radiates to the outside of the skin helping to cool the body down. If the body is too hot small arteries (arterioles) leading to the capillary loops dilate (widen). This increases blood flow to the skins surface and is called vasodilation.
In cold conditions the opposite happens. the arterioles leading the the surface capillary loops constrict ( become narrower) and blood flow to the skin id reduced, so that less heat is lost. This is called vasoconstriction.
In cold conditions the hair erector muscles at the base of the hair on you skin, contract and the hairs are pulled upright. this traps a layer of air next to the skin, and since air is a poor conductor of heat, this acts as insulation.
Shivering also takes place in cold conditions, it is when the muscles relax and contract rapidly. This generates a large amount of heat.
Explain the concept of control by negative feedback in homeostasis
Explain: Give a detailed account
Explain: Give a detailed account
image from www.blendspace.com
Almost all homeostatic control mechanisms are negative feedback mechanisms. These mechanisms change the variable back to its original state or “ideal value”. Negative feedback in homeostasis describes a process by which bodily systems maintain their normal environments or states. Homeostasis describes the body's overall regulation of its internal systems. When changes in a state such as body temperature occur, negative feedback responses are triggered to bring the temperature back to its normal point. For example, if the body becomes too hot, sweating occurs to cool it. If the body becomes too cold, shivering is one response that helps to warm it up
Describe the control of the glucose content of the blood by the liver, and by insulin and glucagon from the pancreas
Describe: Give a detailed account or picture of a situation, event, pattern or process.
Describe: Give a detailed account or picture of a situation, event, pattern or process.
image from dtc.ucsf.edu
The body needs a constant supply of glucose, or sugar, for cells to have energy. The body requires a readily available reservoir to keep blood glucose in balance. One of the liver’s main roles in the body is controlling the amount of glucose circulating in the blood. By storing excess glucose as glycogen and creating new glucose from proteins and fat byproducts, the liver is able to maintain balanced glucose levels in your body at all times
Insulin, a hormone secreted by the pancreas, controls blood sugar levels in the body. It travels from the pancreas to the liver in the bloodstream. As with other responses controlled by hormones, the response is slower but longer lasting than if it had been controlled by the nervous system.
Insulin, a hormone secreted by the pancreas, controls blood sugar levels in the body. It travels from the pancreas to the liver in the bloodstream. As with other responses controlled by hormones, the response is slower but longer lasting than if it had been controlled by the nervous system.
Outline the two different types of diabetes
Outline: Give a brief account
Outline: Give a brief account
image from www.jalanhealthcare.com
Diabetes occurs when the body is no longer able to control the level of glucose in the blood.
In general, people with diabetes either have a total lack of insulin (type 1 diabetes) or they have too little insulin or cannot use insulin effectively (type 2 diabetes).
In type 1 diabetes, the body's immune system destroys the cells that release insulin, eventually eliminating insulin production from the body. Without insulin, cells cannot absorb sugar (glucose), which they need to produce energy.
Type 2 diabetes can develop at any age. It most commonly becomes apparent during adulthood. But type 2 diabetes in children is rising. Type 2 diabetes accounts for the vast majority of people who have diabetes—90 to 95 out of 100 people. In type 2 diabetes, the body isn't able to use insulin the right way. This is called insulin resistance. As type 2 diabetes gets worse, the pancreas may make less and less insulin. This is called insulin deficiency.
In general, people with diabetes either have a total lack of insulin (type 1 diabetes) or they have too little insulin or cannot use insulin effectively (type 2 diabetes).
In type 1 diabetes, the body's immune system destroys the cells that release insulin, eventually eliminating insulin production from the body. Without insulin, cells cannot absorb sugar (glucose), which they need to produce energy.
Type 2 diabetes can develop at any age. It most commonly becomes apparent during adulthood. But type 2 diabetes in children is rising. Type 2 diabetes accounts for the vast majority of people who have diabetes—90 to 95 out of 100 people. In type 2 diabetes, the body isn't able to use insulin the right way. This is called insulin resistance. As type 2 diabetes gets worse, the pancreas may make less and less insulin. This is called insulin deficiency.
Describe the structure of the urinary system, including the kidneys, ureters, bladder and urethra
Describe: Give a detailed account or picture of a situation, event, pattern or process.
Describe: Give a detailed account or picture of a situation, event, pattern or process.
image from training.seer.cancer.gov
The kidneys, ureters, bladder, and urethra work together to remove waste products from the blood. The nephrons of the kidneys are involved in filtering the blood and urine formation. The ureters, bladder, and urethra are responsible for eliminating urine from the body. The kidneys also play an important role in regulating blood cell production by producing the hormone erythropoietin to stimulate the red bone marrow to produce red blood cells. They also help to control blood pressure by producing the hormone renin, which helps regulate blood pressure
Outline the function of the kidneys
Outline: Give brief account
Outline: Give brief account
image from www.ib.bioninja.com.au
The kidneys perform a wide range of vital functions in the healthy body, such as:
- Removing wastes and water from the blood
- Balancing chemicals in your body
- Releasing hormones
- Helping control blood pressure
- Helping to produce red blood cells
- Producing vitamin D, which keeps the bones strong and healthy
Describe the structure of a nephron, to include Bowman’s capsule and glomerulus, convoluted tubules, loop of Henlé and collecting duct
Describe: Give a detailed account or picture of a situation, event, pattern or process
Describe: Give a detailed account or picture of a situation, event, pattern or process
image from www.eurostemcell.org
The nephron is the tiny filtering structure in your kidneys. Each of your kidneys contain more than a million tiny filtering nephrons that help clean your blood.
The 4 regions are:
(a) Bowman's capsule
(b) Proximal convoluted tubule (PCT)
(c) Loop of Henle
(d) Distal convoluted tubule (DCT)
Function of the Nephrons
Remove excess water,wastes and other substances from your blood.
Return substances like sodium, potassium or phosphorus whenever any of these substances run low in your body.
Each nephron is composed of two main structures: the glomerulus and renal (kidney) tubule.
The 4 regions are:
(a) Bowman's capsule
(b) Proximal convoluted tubule (PCT)
(c) Loop of Henle
(d) Distal convoluted tubule (DCT)
Function of the Nephrons
Remove excess water,wastes and other substances from your blood.
Return substances like sodium, potassium or phosphorus whenever any of these substances run low in your body.
Each nephron is composed of two main structures: the glomerulus and renal (kidney) tubule.
image from www.shmoop.com
The Glomerulus
The glomerulus is a tiny blood vessel or capillary, which looks like a ball of yarn. Actual filtering of your blood occurs in the glomerulus.
Each of your glomeruli acts like a sieve that helps keep normal proteins and cells in your bloodstream and allows wastes, excess fluid and other substances to pass.
The glomerulus is a tiny blood vessel or capillary, which looks like a ball of yarn. Actual filtering of your blood occurs in the glomerulus.
Each of your glomeruli acts like a sieve that helps keep normal proteins and cells in your bloodstream and allows wastes, excess fluid and other substances to pass.
image from dlb-network.com
The Tubule
The tubule, also called renal or kidney tubule, is a tiny tube where the wastes, extra fluid and other recyclable substances like sodium and potassium filtered out from the glomerulus pass through.
Your kidneys measure out chemicals like sodium, phosphorus, and potassium and release them back to the blood to return to the body when need arises. In this way, your kidneys regulate the your body’s level of these substances. The right balance is necessary for you to function properly.
The tubule, also called renal or kidney tubule, is a tiny tube where the wastes, extra fluid and other recyclable substances like sodium and potassium filtered out from the glomerulus pass through.
Your kidneys measure out chemicals like sodium, phosphorus, and potassium and release them back to the blood to return to the body when need arises. In this way, your kidneys regulate the your body’s level of these substances. The right balance is necessary for you to function properly.
Describe ultrafiltration in the Bowman’s capsule and the composition of the glomerular filtrate
Describe: Give a detailed account or picture of a situation, event, pattern or process
Describe: Give a detailed account or picture of a situation, event, pattern or process
image from danielscienceblogg.blogspot.com
The Bowman's capsule is where the filtration process begins This process is know as ultrafiltration.
Blood enters the kidney through the blood vessel called afferent arteriole. The blood is under high pressure. Blood vessels start to bend and twist into and become the glomerulus. The blood then comes out through the blood vessel efferent arteriole in which the diameter of this vessel is smaller and more narrow than the afferent arteriole's. The consequence of narrowed vessels is the increase of blood pressure. In other words, the blood pressure increases in the glomerulus. The blood has been filtered due to high pressure because of the smaller area of the blood vessel. The blood has been filtered through undergoing high pressure due to the narrowing glomerulus, which forces in plasma out from the blood into the Bowman's capsule .
Blood enters the kidney through the blood vessel called afferent arteriole. The blood is under high pressure. Blood vessels start to bend and twist into and become the glomerulus. The blood then comes out through the blood vessel efferent arteriole in which the diameter of this vessel is smaller and more narrow than the afferent arteriole's. The consequence of narrowed vessels is the increase of blood pressure. In other words, the blood pressure increases in the glomerulus. The blood has been filtered due to high pressure because of the smaller area of the blood vessel. The blood has been filtered through undergoing high pressure due to the narrowing glomerulus, which forces in plasma out from the blood into the Bowman's capsule .
State that selective reabsorption of glucose occurs at the proximal convoluted tubule
State: Give a specific name, value or other brief answer without explanation or calculation
State: Give a specific name, value or other brief answer without explanation or calculation
image from www.studyblue.com
Selective reabsorption is the reabsorption of specific substances from the glomerulus filtrate back to the blood. Remember, filtration happens in the Bowman's capsule and the glomerulus filtrate contains the glucose, water, salts, amino acids and urea. This may seem strange because it has been removed from the blood and now going to be put back into the blood.
Glucose is removed from the glomerulus filtrate in the proximal convoluted tubule just before the Loop of Henle .
Glucose is usually not found in urine. However, if urine tests positive for glucose, the individual may have a condition known as diabetes.
Glucose is removed from the glomerulus filtrate in the proximal convoluted tubule just before the Loop of Henle .
Glucose is usually not found in urine. However, if urine tests positive for glucose, the individual may have a condition known as diabetes.
Outline how water is reabsorbed into the blood from the collecting duct and the role of ADH in regulating the water content of the blood
Outline: Give a brief account.
Outline: Give a brief account.
image from andrewbiology.blogspot.com
The amount of water in the blood must be kept the same all the time to avoid cell damage as a result of osmosis. There has to be a balance between the amount of water gained (from your diet though drinks and food and the water produced by cellular respiration) and the amount of water lost by the body (in sweating, evaporation, faeces and urine).
This is achieved by the action of the hormone ADH (anti-diuretic hormone).
The hypothalamus, detects that there is not enough water in the blood. The hypothalamus sends a message to the pituitary gland which releases ADH. This travels in the blood to your kidneys and affects the tubules so more water is reabsorbed into your blood. As a result you make a smaller volume of more concentrated urine. The level of water in your blood increases until it is back to normal.
Sometimes the level of water in your blood goes up because, for example, it is cold and you have not been losing any water through sweating or because you have had a lot to drink. The hypothalamus detects the change and sends a message to the pituitary. The release of ADH into the blood is slowed down or even stopped. Without ADH the kidneys will not save as much water and you produce large volumes of dilute urine. The level of water in the blood falls back to the normal level.
This is an example of negative feedback. As the level of water in the blood falls, negative feedback ensures that the amount of ADH rises. As the level of water in the blood rises negative feedback ensures that the amount of ADH falls
This is achieved by the action of the hormone ADH (anti-diuretic hormone).
The hypothalamus, detects that there is not enough water in the blood. The hypothalamus sends a message to the pituitary gland which releases ADH. This travels in the blood to your kidneys and affects the tubules so more water is reabsorbed into your blood. As a result you make a smaller volume of more concentrated urine. The level of water in your blood increases until it is back to normal.
Sometimes the level of water in your blood goes up because, for example, it is cold and you have not been losing any water through sweating or because you have had a lot to drink. The hypothalamus detects the change and sends a message to the pituitary. The release of ADH into the blood is slowed down or even stopped. Without ADH the kidneys will not save as much water and you produce large volumes of dilute urine. The level of water in the blood falls back to the normal level.
This is an example of negative feedback. As the level of water in the blood falls, negative feedback ensures that the amount of ADH rises. As the level of water in the blood rises negative feedback ensures that the amount of ADH falls
image from en.wikipedia.org
image from s27.photobucket.com
Key Terms:
|
homeostasis
excretion urine metabolism nitrogen osmoregulation urea renal artery renal vein bladder |
ureters
urethra sphincter vasoconstriction vasodilation sweat pileoerection shivering adrenaline latent heat glycogon |
epidermis
hypodermis dermis vaporisation dilate constrict cortex nephrons medulla bladder glycogen |
loop of Henle
Bowman capsule glomerulus collecting duct filtrate arterioles ultrafiltration ADH hypothalamus water liver |
selective reabsorption
homeothermic endotherms negative feedback denature thermoregulatory centre thermostat diabetic glucose insulin |
Class Materials:
Part 1 Homeostasis and Temperature Control
Part 2 Controlling Glucose
Part 3 The Kidney and Water Control
Homeostasis.
Homeostasis Study Guide
Homeostasis Poster.
How Much Is That Kidney In The Window WebWalk
Homeostasis and Sports Drinks WebWalk
Kidney Transplant vs Dialysis (in class assignment)
Choose a single animal (other than human) and describe how is carries out its homeostasis with respect to water and salt balance. Provide a detailed drawing or image (reference source) to illustrate your answer. please include diagrams or pictures may be right from the web. Please look at the Malpighian diagram to help you answer the questions
Kidney Practical
Useful Links:
Read the 3 articles on Homeostasis
Check out this animation of vasoconstriction
Check out this useful website on Homeostasis
Osmoregulation Review from Shmoop
Water Balance and The Kidney from Shmoop
Check out this animation on diabetes.
Click here for a great animation on Positive and Negative Feedback
Biology 4 Kids
McGraw Hill Positive and Negative Feedback animation
Great Kidney animation from Interactive Human
A great review from KScience on ADH and the Kidneys
Video clip on Fight or Flight Response from
Homeostasis Study Guide
Homeostasis Poster.
How Much Is That Kidney In The Window WebWalk
Homeostasis and Sports Drinks WebWalk
Kidney Transplant vs Dialysis (in class assignment)
Choose a single animal (other than human) and describe how is carries out its homeostasis with respect to water and salt balance. Provide a detailed drawing or image (reference source) to illustrate your answer. please include diagrams or pictures may be right from the web. Please look at the Malpighian diagram to help you answer the questions
Kidney Practical
Useful Links:
Read the 3 articles on Homeostasis
Check out this animation of vasoconstriction
Check out this useful website on Homeostasis
Osmoregulation Review from Shmoop
Water Balance and The Kidney from Shmoop
Check out this animation on diabetes.
Click here for a great animation on Positive and Negative Feedback
Biology 4 Kids
McGraw Hill Positive and Negative Feedback animation
Great Kidney animation from Interactive Human
A great review from KScience on ADH and the Kidneys
Video clip on Fight or Flight Response from
Video Clips:
Hank takes us on the fascinating journey through our excretory system to learn how our kidneys make pee.
Paul Andersen explains how feedback loops allow living organisms to maintain homeostasis. He uses thermoregulation in mammals to explain how a negative feedback loop functions. He uses fruit ripening to explain how a positive feedback loop functions. He also explains what can happen when a feedback look is altered. Diabetes mellitus is caused by an alteration in the blood glucose feedback loop
Understand how important insulin is for your body
