Questions and Answers
What is the primary function of the kidneys in the excretory system?
Which of the following excretory organs primarily removes carbon dioxide from the blood?
What is mainly excreted by the sweat glands in the skin?
Which substance is formed from the deamination of proteins in the liver?
Signup and view all the answers
Which excretory organ is responsible for eliminating excess inorganic substances through the feces?
Signup and view all the answers
What is the filtrate primarily composed of?
Signup and view all the answers
What is the main process required to convert filtrate into urine?
Signup and view all the answers
What type of capillaries make up the glomerulus?
Signup and view all the answers
What role do special cells in the Bowman’s capsule play?
Signup and view all the answers
Which feature of the afferent arteriole aids in the filtration process?
Signup and view all the answers
What is the shape of the Bowman’s capsule and its significance?
Signup and view all the answers
What network surrounds the proximal convoluted tubules for selective reabsorption?
Signup and view all the answers
What is primarily removed from the body through the excretion process?
Signup and view all the answers
What is the primary function of the urethra?
Signup and view all the answers
Which component primarily carries oxygenated blood to the kidneys?
Signup and view all the answers
Which part of the kidney is responsible for processing the majority of the filtrate?
Signup and view all the answers
What role does the Malpighian body serve in the kidney?
Signup and view all the answers
What is the key difference between afferent and efferent arterioles?
Signup and view all the answers
What process describes the movement of substances from the renal tubules back into the bloodstream?
Signup and view all the answers
During which condition is ADH secreted to increase water reabsorption in the kidneys?
Signup and view all the answers
Which part of the nephron is primarily involved in the initial filtration of blood?
Signup and view all the answers
What type of reabsorption often occurs against the concentration gradient?
Signup and view all the answers
What structures in cuboidal cells increase the surface area for reabsorption?
Signup and view all the answers
Which process does NOT require energy for reabsorption?
Signup and view all the answers
What is primarily reabsorbed in the loop of Henle?
Signup and view all the answers
What type of molecules are actively excreted into the distal convoluted tubule?
Signup and view all the answers
Which ions does the distal tubule regulate to affect blood pH?
Signup and view all the answers
What characteristic of desert animals like camels allows them to conserve water effectively?
Signup and view all the answers
Which substances are NOT retained during the reabsorption process?
Signup and view all the answers
What happens when there is an increase in ADH secretion?
Signup and view all the answers
What results from a high concentration of water in the blood?
Signup and view all the answers
Which nitrogenous waste is eliminated by the kidneys?
Signup and view all the answers
Which process is involved in maintaining the blood's pH level?
Signup and view all the answers
What is the role of the kidneys in osmoregulation?
Signup and view all the answers
What is NOT a function of the kidneys?
Signup and view all the answers
How do the kidneys and pituitary gland interact to maintain water content?
Signup and view all the answers
What characterizes the urine produced when less water is reabsorbed?
Signup and view all the answers
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.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
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.