Absorptive and postabsorptive state of metabolism. Metabolic States of the Body · Anatomy and Physiology 2022-12-23
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The human body is constantly undergoing metabolic processes to sustain life and maintain homeostasis. These processes can be divided into two main states: the absorptive state and the postabsorptive state.
The absorptive state, also known as the fed state, occurs when the body is actively digesting and absorbing nutrients from food. This typically occurs after a meal has been consumed and can last for several hours. During the absorptive state, the body's main energy source is glucose, which is derived from the breakdown of carbohydrates in the diet. Glucose is used by cells throughout the body to produce energy and support various physiological processes.
In contrast, the postabsorptive state, also known as the fasting state, occurs when the body is not actively digesting and absorbing nutrients. This typically occurs between meals or during periods of extended fasting. During the postabsorptive state, the body's main energy source shifts from glucose to fat. The liver breaks down stored glycogen into glucose, which is then released into the bloodstream to be used by cells as an energy source. If glycogen stores become depleted, the body begins to break down fats from fat cells and convert them into molecules called ketones, which can also be used by cells as an energy source.
The absorptive and postabsorptive states have important implications for energy metabolism and overall health. In the absorptive state, the body is able to easily obtain energy from the diet, which can be used to support various physiological processes. However, if the body is constantly in the absorptive state and consuming more calories than it needs, it can lead to weight gain and other negative health outcomes. On the other hand, the postabsorptive state can be beneficial for weight loss and improving overall health, as it forces the body to rely on stored energy sources rather than constantly consuming new nutrients.
In conclusion, the absorptive and postabsorptive states of metabolism refer to the body's use of nutrients and energy sources at different times. Understanding these states can help individuals make informed decisions about their diet and lifestyle to support optimal health.
24.5 Metabolic States of the Body
Adipoctytes obtain the lipids from chylomicrons, from VLDLs, and from their own synthesis reactions. Insulin also promotes the synthesis of protein in muscle. As starvation continues, fatty acids and triglyceride stores are used to create ketones for the body. Oxidation of Lactic Acid: -cardiac muscles produce ATP aerobically from lactic acid. As starvation continues, fatty acids and triglyceride stores are used to create ketones for the body. Some fatty acids and triglycerides synthesized in liver remain there but hepatocytes package most into VLDLs which carry lipids to adipose tissue for storage.
As starvation continues, fatty acids and triglyceride stores are used to create ketones for the body. An adipocyte contains a small amount of cytoplasm, which surrounds a large lipid droplet. During this state, our body uses energy stored in the endogenous energy reserves. Post-absorptive state is the period during which the GI tract is empty of nutrients and body stores must supply the required energy. Pyruvate can undergo changes depending on if it is in anaerobic or aerobic conditions, but in the process of creating ATP, it has a conformational change to another molecule called acetyl CoA which enters the second stage of the cycle known as the Citric Acid Cycle. If not, the excess glucose is stored as glycogen in the liver and muscle cells, or as fat in adipose tissue; excess dietary fat is also stored as triglycerides in adipose tissues.
An appointment was made for her to attend a diabetes clinic. One candidate is nitrosamines, found in some smoked foods, which have been shown to be toxic to pancreatic β-cells in animals. During the absorptive state, our body digests foods and absorbs nutrients into the blood. This acetoacetyl CoA is subsequently converted into β-hydroxybutyrate, the most common ketone in the body. If not, the excess glucose is stored as glycogen in the liver and muscle cells, or as fat in adipose tissue; excess dietary fat is also stored as triglycerides in adipose tissues. When the body is fed, glucose, fats, and proteins are absorbed across the intestinal membrane and enter the bloodstream and lymphatic system to be used immediately for fuel. Thus, this is the key difference between absorptive and postabsorptive state.
metabolsim during absorptive and postabsorptive states Flashcards
Temperature-regulating reflexes Changes in body temperature are detected by two types of thermoreceptors, ones in the skin peripheral thermoreceptors and ones in the hypothalamus, spinal cord, etc. If the disease is not controlled properly, this inability to process the glucose can lead to starvation states even though the patient is eating. If energy is exerted shortly after eating, the dietary fats and sugars that were just ingested will be processed and used immediately for energy. It takes up a large fraction of the nutrients, thereby altering the composition of the blood before it circulates to the rest of the body. The importance of the postabsorptive state is to maintain blood glucose levels.
During this state glucose is the most important energy fuel. Glucose levels in the blood begin to drop as it is absorbed and used by the cells. Therefore, the body uses ketones to satisfy the energy needs of the brain and other glucose-dependent organs, and to maintain proteins in the cells see After several days of starvation, ketone bodies become the major source of fuel for the heart and other organs. The constituent parts of these carbohydrates, fats, and proteins are transported across the intestinal wall and enter the bloodstream sugars and amino acids or the lymphatic system fats. When triglycerides and fatty acids are broken down, acetyl CoA is created. Once inside these cells, glucose is immediately converted into glucose-6-phosphate. Postabsorptive State: Resting after absorption of meal.
Chapter 25: Absorptive and Postabsorptive States Flashcards
The gluconeogenesis that has been ongoing in the liver will continue after fasting to replace the glycogen stores that were depleted in the liver. After these stores have been replenished, excess glucose that is absorbed by the liver will be converted into triglycerides and fatty acids for long-term storage. The hypothalamus serves as the overall integrator of reflexes and sends outputs via sympathetic nerves to sweat glands, skin arterioles, and adrenal medulla and via motor neurons to skeletal muscles. Most of the activity contributing to basal metabolic rate is from the activity of the heart, liver, kidney, and brain. Vasoconstriction and shivering occur to drive up body temperature. If the fast is not broken and starvation begins to set in, during the initial days, glucose produced from gluconeogenesis is still used by the brain and organs.
Difference Between Absorptive and Postabsorptive State
This allows for glucose to continue moving from the blood to the cells where it is needed. In response to a drop in blood glucose concentration, the hormone glucagon is released from the alpha cells of the pancreas. The constituent parts of these carbohydrates, fats, and proteins are transported across the intestinal wall and enter the bloodstream sugars and amino acids or the lymphatic system fats. Insulin also promotes the synthesis of protein in muscle. What is Postabsorptive State? Describe how ketones are synthesized. Glucose levels in the blood begin to drop as it is absorbed and used by the cells. In this chapter we shall consider the metabolic abnormalities present in this condition, and the consequences of these defects A 12-year-old girl was taken to see her doctor.
Metabolic States of the Body · Anatomy and Physiology
If there were no method in place to store excess energy, you would need to eat constantly in order to meet energy demands. She was told to fast from the evening before the appointment. The excess fat is deposited in the adipose tissue. Absorptive state or fed state is the time immediately after a meal. Sodium loss through sweat is reduced by its increased reabsorption due to aldosterone secretion. Thus as the concentration of insulin in the blood rises, the concentration of glucose falls and the stimulus for insulin secretion is removed.
The second priority is the conservation of amino acids for proteins. However, chronic insulin and glucagon deficiencies have been proven to cause hyperglycemia and, therefore, strongly suggest that insulin is the predominant factor of postabsorptive glucose levels. Moreover, insulin plays a major role in the absorptive state, while glucagon plays a major role during the postabsorptive state. The feedback control of insulin secretion by plasma glucose is summarized in The concentration of plasma insulin normally parallels the rise and fall in the levels of plasma glucose. Starvation states happen very rarely in generally well-nourished individuals. These plateaus occur within a postabsorptive physiological range, and after octreotide-induced suppression of insulin and glucagon secretion.