Chapter 23 - Urinary Flashcards
What are the main functions of the kidneys?
- Removal of toxins, metabolic wastes, and excess ions from the blood.
- Regulation of blood volume, chemical composition, and pH.
- Gluconeogenesis during prolonged fasting. ( formation of new glucose from glycerol and amino acids)
- Endocrine functions: Erythropoietin for RBC production, and Renin for blood pressure and kidney function regulation.
- Activation of vitamin D.
What are the nitrogenous wastes?
Nitrogenous wastes are substances that are either useless to the body or present in excess of the body’s needs. They include urea, uric acid, and creatinine.
What is the purpose of the urea formation process?
Urea formation involves converting ammonia, which is derived from amino acids, into urea in the liver. This helps to eliminate excess nitrogen from the body.
Label the structures of the urinary system
Name the different types of nephrons and their characteristics.
Juxtamedullary nephrons:
* 15% of all nephrons
* Long nephron loops that help maintain salinity gradient in the medulla.
* Efferent arterioles branch into vasa recta around long nephron loop
Cortical nephrons:
* 85% of all nephrons.
* Short nephron loops.
* Efferent arterioles branch into peritubular capillaries around PCT and DCT
How many nephrons are present in each kidney?
There are approximately 1 million nephrons per kidney.
What are the two main parts of a nephron?
The two main parts of a nephron are the renal corpuscle, which filters the blood plasma, and the** renal tubule**, long coiled tube which converts the filtrate into urine.
Label the structures of the renal corpuscle
What is the role of the glomerulus?
The glomerulus is a network of capillaries in the renal corpuscle responsible for filtering blood to create the glomerular filtrate.
what is glomerular filtration rate (GFR)
What are the basic stages of urine formation?
The basic stages of urine formation include: 1) Glomerular filtration, which creates a plasmalike filtrate. 2) Tubular reabsorption, which removes useful solutes from the filtrate. 3) Tubular secretion, which removes additional wastes from the blood. 4) Water conservation, which removes water from the urine and concentrates wastes.
How does the proximal convoluted tubule (PCT) contribute to urine formation?
The PCT reabsorbs about 65% of glomerular filtrate, removing some substances from the blood and secreting them into the tubular fluid for disposal in urine. It absorbs nutrients such as glucose and sodium ions.
What is the role of the loop of Henle?
The loop of Henle, found in juxtamedullary nephrons, creates an osmotic gradient in the renal medulla, which is critical for water conservation in the urine.
What distinguishes the distal tubule and collecting duct from the proximal tubule?
The distal tubule and collecting duct are more regulated than the proximal tubule. They have fewer microvilli, fewer mitochondria, and hormone receptors that respond to hormones like ADH and aldosterone.
the process of water conservation and control of water loss
Label the urinary system structures
Explain the process of micturition.
Micturition, or urination, involves the micturition reflex, an involuntary spinal reflex. It includes bladder stretch receptors, parasympathetic and voluntary control, detrusor muscle contraction, and relaxation of urethral sphincters.
