Grant Sanders


The Kidney
1. Describe the path of urine and the structure and function of each organ in this path. (detail). pp.188-189
The path of urine goes from the kidneys to the ureters, to the urinary bladder, and finally the Urethra. Kidneys-paired organs located near the small of the back, on either side of the vertebrae column. Ureters- conduct urine from the kidneys to the bladder. Urinary bladder- stores urine until it is expelled from the body. Urethra- small tube that extends from the urinary bladder to an external opening.
2. Describe the four functions of the kidney and how they contribute to homeostasis (balance) (detail) p. 189
Excretion of Metabolic Wastes- The kidneys excrete metabolic wastes, notably nitrogenous wastes.
Maintenance of water- A principle function of the kidneys is to maintain the appropriate water salt balance of the blood.
Maintenance of acid-base balance- The kidneys regulate acid-base balance of the blood.
Secretion of Hormones- The kidneys assist the endocrine system in hormone secretion.
3. Trace the path of blood through the kidney. pp.191-192
The renal cortex is the outer layer, then the renal medulla consisting of cone shaped tissue masses called renal pyramids, and last the renal pelvis is the central space that is continuous with the ureter.
4. What microscopic structure is responsible for the production of urine in the kidney? p. 191
Nephrons are responsible for the production of the urine in the kidneys.
5. Describe the parts of the nephron (detail). pp.192-193
Glomerular capsule- the closed end of the nephron is pushed in on itself to form a cuplike structure.
Proximal convoluted tubule- The cuboidal epithelial cells lining this part of the nephron have numerous microvilli tightly packed and form a brush border.
Loop of the nephron- Simple squamous epithelium appears as the tube narrows and makes a U-turn.
Distal convoluted tubule-numerous mitochondria, but they lack microvilli.
Collecting ducts- Many ducts carry urine to the renal pelvis.
6. What are the major processes of urine formation and how does the nephron carry out each process? p. 195
Glomerular filtration- occurs when whole blood enters the glomerulus by way of afferent arteriole.
Tubular Reabsorption- occurs as molecules and ions are both passively and actively reabsorbed from the nephron into the blood of the peritubular capillary network.
Tubular Secretion- a second way by which substances are removed from the blood and added to the tubular fluid
7. Explain how an artificial kidney cleanses the blood. p. 200
As the patient’s blood is pumped through dialysis tubing, it is exposed to a dialysate. Wastes exit from blood into the solution because of a preestablished concentration gradient.
8. How do the kidneys assist other body systems? p. 201-202
The kidneys assist the endocrine system and also the cardiovascular system by producing erythropoietin.