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Questions and Answers
What is the primary function of the kidneys in the excretory system?
What is the primary function of the kidneys in the excretory system?
- Eliminating urine and regulating water and salt concentration (correct)
- Removing carbon dioxide from the blood
- Detoxifying ingested poisons
- Eliminating sweat through the skin
Which of the following excretory organs primarily removes carbon dioxide from the blood?
Which of the following excretory organs primarily removes carbon dioxide from the blood?
- Lungs (correct)
- Liver
- Kidneys
- Skin
What is mainly excreted by the sweat glands in the skin?
What is mainly excreted by the sweat glands in the skin?
- Calcium and iron
- Sodium chloride and water (correct)
- Metabolic wastes and potassium
- Nitrogenous wastes and urea
Which substance is formed from the deamination of proteins in the liver?
Which substance is formed from the deamination of proteins in the liver?
Which excretory organ is responsible for eliminating excess inorganic substances through the feces?
Which excretory organ is responsible for eliminating excess inorganic substances through the feces?
What is the filtrate primarily composed of?
What is the filtrate primarily composed of?
What is the main process required to convert filtrate into urine?
What is the main process required to convert filtrate into urine?
What type of capillaries make up the glomerulus?
What type of capillaries make up the glomerulus?
What role do special cells in the Bowman’s capsule play?
What role do special cells in the Bowman’s capsule play?
Which feature of the afferent arteriole aids in the filtration process?
Which feature of the afferent arteriole aids in the filtration process?
What is the shape of the Bowman’s capsule and its significance?
What is the shape of the Bowman’s capsule and its significance?
What network surrounds the proximal convoluted tubules for selective reabsorption?
What network surrounds the proximal convoluted tubules for selective reabsorption?
What is primarily removed from the body through the excretion process?
What is primarily removed from the body through the excretion process?
What is the primary function of the urethra?
What is the primary function of the urethra?
Which component primarily carries oxygenated blood to the kidneys?
Which component primarily carries oxygenated blood to the kidneys?
Which part of the kidney is responsible for processing the majority of the filtrate?
Which part of the kidney is responsible for processing the majority of the filtrate?
What role does the Malpighian body serve in the kidney?
What role does the Malpighian body serve in the kidney?
What is the key difference between afferent and efferent arterioles?
What is the key difference between afferent and efferent arterioles?
What process describes the movement of substances from the renal tubules back into the bloodstream?
What process describes the movement of substances from the renal tubules back into the bloodstream?
During which condition is ADH secreted to increase water reabsorption in the kidneys?
During which condition is ADH secreted to increase water reabsorption in the kidneys?
Which part of the nephron is primarily involved in the initial filtration of blood?
Which part of the nephron is primarily involved in the initial filtration of blood?
What type of reabsorption often occurs against the concentration gradient?
What type of reabsorption often occurs against the concentration gradient?
What structures in cuboidal cells increase the surface area for reabsorption?
What structures in cuboidal cells increase the surface area for reabsorption?
Which process does NOT require energy for reabsorption?
Which process does NOT require energy for reabsorption?
What is primarily reabsorbed in the loop of Henle?
What is primarily reabsorbed in the loop of Henle?
What type of molecules are actively excreted into the distal convoluted tubule?
What type of molecules are actively excreted into the distal convoluted tubule?
Which ions does the distal tubule regulate to affect blood pH?
Which ions does the distal tubule regulate to affect blood pH?
What characteristic of desert animals like camels allows them to conserve water effectively?
What characteristic of desert animals like camels allows them to conserve water effectively?
Which substances are NOT retained during the reabsorption process?
Which substances are NOT retained during the reabsorption process?
What happens when there is an increase in ADH secretion?
What happens when there is an increase in ADH secretion?
What results from a high concentration of water in the blood?
What results from a high concentration of water in the blood?
Which nitrogenous waste is eliminated by the kidneys?
Which nitrogenous waste is eliminated by the kidneys?
Which process is involved in maintaining the blood's pH level?
Which process is involved in maintaining the blood's pH level?
What is the role of the kidneys in osmoregulation?
What is the role of the kidneys in osmoregulation?
What is NOT a function of the kidneys?
What is NOT a function of the kidneys?
How do the kidneys and pituitary gland interact to maintain water content?
How do the kidneys and pituitary gland interact to maintain water content?
What characterizes the urine produced when less water is reabsorbed?
What characterizes the urine produced when less water is reabsorbed?
Study Notes
Excretory Organs and Homeostasis
- Excretory organs maintain optimal internal state by removing metabolic wastes and regulating water balance (osmoregulation).
- They play a critical role in homeostasis, ensuring cell survival within a controlled environment.
Main Excretory Organs
- Kidneys: Eliminate urine, which consists of excess water, salts, and nitrogenous wastes; regulate water and salt concentration in the body.
- Lungs: Remove carbon dioxide from the blood through diffusion at the alveoli.
- Skin: Sweat glands eliminate sweat, containing water, salts (mainly sodium chloride), and some nitrogenous wastes, but in lower concentration than urine.
- Liver: Eliminates cellular wastes, processes hemoglobin from red blood cells, deaminates proteins to form urea, and detoxifies ingested poisons.
- Alimentary Canal: Excretes metabolic wastes and excess inorganic substances into the large intestine, which are eliminated as feces along with a filtrate that contains useful substances and waste.
Structural Features of the Malpighian Body
- Glomerulus: A network of capillaries that increases surface area for ultra-filtration; walls are thin to allow substance passage, and arterioles create pressure for efficient filtration.
- Bowman’s Capsule: Has a cup shape to increase surface area; consists of a single layer of epithelial cells for easy passage of substances.
Selective Reabsorption
- Useful substances are reabsorbed from proximal convoluted tubules into surrounding capillaries, involving both active (energy-consuming) and passive (energy-free) transport.
- Active reabsorption often occurs against the concentration gradient using carrier molecules; cells possess many mitochondria for energy.
- The presence of microvilli increases surface area for efficient reabsorption; water reabsorption primarily occurs through osmosis.
- Excess vitamins/minerals are not reabsorbed if levels exceed physiological capacity; the loop of Henle optimizes water conservation, especially in desert animals.
Tubular Excretion
- At the distal convoluted tubule, large wastes (e.g., creatinine) are actively excreted; smaller wastes like urea passively exit the blood.
- Drug elimination occurs, and the distal tubule regulates blood pH by managing H+ and bicarbonate ions.
- The release of antidiuretic hormone (ADH) influences water permeability in tubules, adjusting urine concentration depending on blood water levels.
Functions of the Kidneys
- Excretion: Removes nitrogenous wastes like urea and uric acid.
- Osmoregulation: Maintains normal salt and water levels in the blood.
- pH Control: Regulates pH by excreting H+ or bicarbonate ions to keep blood slightly alkaline.
- Toxin Control: Eliminates some ingested poisons.
Implications for Homeostasis
- Kidneys control chemical balance between the body and environment through osmoregulation, affecting blood volume and intercellular fluid levels, crucial for cell function.
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Description
Explore the functions and importance of the excretory organs in maintaining homeostasis in the body. This quiz covers the main excretory organs like kidneys and lungs, focusing on their roles in waste removal and osmoregulation. Test your knowledge on how these organs contribute to the optimal internal environment for cellular survival.
