Homeostasis- lecture 4 and 5 pt2

winniesmith1's version from 2017-05-01 15:06

Section 1

Question Answer
What are nephronsstructural and functional unit of the kidneys, where urine production begins (filtration)
What is the structure of nephronsMicroscopic, tubular structures in the cortex of each renal lobe
What are the 2 types of nephronscortical and juxtamedullary nephrons
Nephron associated blood vessels• Blood entering the kidney through the renal artery flows first into the segmental arteries. • There, it enters the interlobar arteries, the arcuate arteries, the small cortical radiate arteries, and the still smaller afferent arterioles, which empty into a capillary bed called the glomerulus. • Leading away from the glomerulus is the efferent arteriole (larger in diameter than the efferent arteriole). • Blood passes from the efferent arteriole into the peritubular capillaries and vasa recta. • From there, blood drains into the cortical radiate vein, flows into the arcuate vein and enters the interlobar vein, eventually reaching the renal vein.

Section 2

Question Answer
Renal corpusclecontains glomerulus. Production of filtrate
Proximal convoluted tubuleReabsorption of water, ions, and all organic material
Distal convoluted tubule-secretion of ions, acids, drugs, toxins. Variable reabsorption of water, sodium ions, and calcium ions (under hormonal control).
Collecting ductVariable reabsorption of water and reabsorption/secretion of sodium, potassium, hydrogen, and bicarbonate ions
Papillary ductDelivery of urine to minor calyx
Nephron loopFurther reabsorption of water (descending limb) and both sodium and chloride ions (ascending limb)

Section 3

Question Answer
Describe the renal cortexSuperficial portion of kidney in contact with renal capsule, Reddish brown and granular, It contains about one million nephrons, the filtering units that form urine.
Describe the renal medullaThe middle layer of the kidney - in which the triangular renal pyramids are.
Describe the triangular renal pyramidsLook striated because of parallel bundles of ducts carrying urine from the nephrons. The areas between pyramids are the renal columns. Renal columns are extensions of the cortex that provide a route for the passage of blood vessels and nerves to and from the outer cortex.
Describe the renal pelvisThe funnel-shaped renal pelvis is within the renal sinus. Collects urine from the pyramids and conveys it into the ureter for passage to the urinary bladder.

Section 4

Question Answer
What are the basic processes of urine formationFiltration, reabsorption and secretion
Describe filtrationWhere the formation of urine production begins. Fluid and small solutes are forces under pressure to flow from the glomerulus into the capsular space of the glomerular capsule (in the neprhon). Rate depends on blood pressure and blood volume.
What stays in the blood Larger solutes (plasma proteins)
Describe reabsorptionAs the filtrate passes through the tubules, specific substances are reabsorbed back into the blood of the peritubular capillaries.
Describe secretionsome solutes are removed from the blood of the peritubular capillaries and secreted by the tubular cells into the filtrate to “fine tune” the composition of the blood.
What is net filtration pressurethe glomerular hydrostatic pressure minus the opposing forces of capsular hydrostatic pressure and glomerular osmotic pressure.

Section 5

Question Answer
What is artificial filtration calledkidney dialysis
How does kidney dialysis workA tube carries blood from a blood vessel his forearm to a dialysis machine (upper right). This acts as an 'artificial kidney' to remove waste products and excess fluid from the blood. The filtered blood is then returned through a second tube into the patient's body. Haemodialysis takes between 2 and 6 hours and must be carried out several times a week.
What is the presence of protein in the urine called?Proteinuria.
What is the presence of blood cells in the urine called?Hematuria.
How much filtrate does the glomeruli generate a dayabout 180 liters. 99% reabsorbed in renal tubules.
What controls glomerular filtrationAutoregulation (local level). Hormonal regulation (initiated by kidneys). Autonomic regulation (by sympathetic division of the autonomic nervous system).
Describe autoregulation of GFRMaintains GFR despite changes in local blood pressure and blood flow. By changing diameters of afferent arterioles, efferent arterioles, and glomerular capillaries.
What happens to control of GFR during periods of severe blood lossthe sympathetic nervous system overrides the renal autoregulatory mechanisms to shunt the blood to other critical areas.