Metabolism
Utilizing knowledge from your learning and assigned readings, respond to the following questions:
- Ketosis develops in the postabsorptive state. What is ketosis? Why does it develop? What metabolic effects does it have?
- What happens during protein catabolism? How is this related to nitrogen balance?
- Briefly outline the role of the liver in glucose metabolism.
The Urinary System
Utilizing knowledge from your learning and assigned readings, respond to the following questions:
- List each organ of the urinary system and concisely describe its function.
- Identify and describe the three major processes involved in urine formation.
- What is the creatinine clearance?
Expert Solution Preview
Introduction:
In this assignment, we will be discussing two topics: metabolism and the urinary system. We will be answering questions related to these topics using our knowledge from assigned readings and lectures.
Metabolism:
1. Ketosis is a metabolic state that occurs when the body is unable to produce enough glucose for energy and instead starts breaking down fat for energy production. Due to the breakdown of fats, ketones are formed, which are used as an alternative fuel source. Ketosis develops in the post-absorptive state because the body starts using its stored energy when no more energy is coming from the digestive system. Ketosis has several metabolic effects, including decreased insulin secretion, increased glucagon secretion, increased lipolysis, and increased ketone body production.
2. During protein catabolism, proteins are broken down into amino acids, which are then oxidized for energy production or synthesized into new proteins for growth and repair. Nitrogen balance refers to the balance between nitrogen intake and nitrogen excretion. Protein catabolism increases nitrogen excretion, which can lead to a negative nitrogen balance if protein intake is not increased.
3. The liver plays a critical role in glucose metabolism. It helps maintain normal blood glucose levels by regulating glucose production and storage. The liver can store glucose as glycogen and release it when needed, and it can also convert non-carbohydrate sources into glucose through gluconeogenesis. In addition, the liver produces and releases glucose into the bloodstream through glycogenolysis.
The Urinary System:
1. The organs of the urinary system include the kidneys, ureters, urinary bladder, and urethra. The kidneys filter waste products from the blood, reabsorb useful substances, and produce urine. The ureters transport urine from the kidneys to the urinary bladder. The urinary bladder stores urine until it is excreted through the urethra.
2. The three major processes involved in urine formation include filtration, reabsorption, and secretion. Filtration occurs in the glomerulus, where blood is filtered to produce a filtrate that contains water, electrolytes, and waste products. Reabsorption occurs primarily in the proximal tubule, where useful substances such as glucose and amino acids are reabsorbed. Secretion occurs in the distal tubule and collecting duct, where waste products such as urea and creatinine are secreted into the urine.
3. Creatinine clearance is a measure of how well the kidneys are filtering creatinine from the blood. Creatinine is a waste product produced by muscle metabolism, and its clearance rate provides an estimate of the glomerular filtration rate, which is a measure of kidney function. Creatinine clearance is calculated by measuring the amount of creatinine in a 24-hour urine sample and comparing it to the level of creatinine in the blood.
