Excretory System and Kidney Function

Excretory System

Kidney Function

• Filtration: blood pressure forces water, ions, and small molecules out of capillaries into Bowman's capsule
• Reabsorption: necessary substances (e.g., glucose, amino acids) are reabsorbed into bloodstream
• Secretion: waste and excess substances (e.g., urea, creatinine) are secreted into filtrate
• Excretion: waste-filled filtrate becomes urine, which flows through ureters to bladder

Osmoregulation and Homeostasis

• Osmoregulation: regulation of solute concentration in bodily fluids to maintain proper osmotic balance
• Homeostasis: maintenance of constant internal environment despite changes in external environment
• Kidney's role in osmoregulation:
  • Regulates water reabsorption to maintain proper blood volume and pressure
  • Controls electrolyte levels (e.g., Na+, K+, Ca2+) to maintain proper ion balance
• Negative feedback mechanisms:
  • Renin-angiotensin-aldosterone system (RAAS) regulates blood pressure and electrolyte balance
  • Antidiuretic hormone (ADH) regulates water reabsorption and urine concentration

Excretory System

Kidney Function

• Blood pressure forces water, ions, and small molecules out of capillaries into Bowman's capsule through filtration
• Glucose, amino acids, and other necessary substances are reabsorbed into the bloodstream
• Waste and excess substances like urea, creatinine, are secreted into the filtrate
• The waste-filled filtrate becomes urine, flowing through ureters to the bladder for excretion

Osmoregulation and Homeostasis

• Osmoregulation maintains proper osmotic balance in bodily fluids by regulating solute concentration
• Homeostasis maintains a constant internal environment despite changes in the external environment
• The kidney regulates water reabsorption to maintain proper blood volume and pressure
• The kidney controls electrolyte levels, such as Na+, K+, Ca2+, to maintain proper ion balance
• The renin-angiotensin-aldosterone system (RAAS) regulates blood pressure and electrolyte balance through negative feedback mechanisms
• Antidiuretic hormone (ADH) regulates water reabsorption and urine concentration through negative feedback mechanisms

This quiz covers the functions of the kidneys, including filtration, reabsorption, secretion, and excretion, as well as osmoregulation and homeostasis in the human body.