The Renal/Urinary System Flashcards
Kidneys help maintain homeostasis throughout the body by performing the following functions
Regulation of ion levels in the blood
Regulation of blood volume and blood pressure
Regulation of blood pH
Production of hormones
Internally, the kidneys consists of
renal cortex, renal medulla, renal pyramids, renal columns, major and minor calyces, and a renal pelvis
How many nephrons (filtering units) are in each kidneys
About a million
Nephron consists of 2 parts
renal corpuscle where blood plasma is filtered
renal tubule into which the filtered fluid passes
2 parts that make up a renal corpuscle
the glomerulus and glomerular (Bowman’s) capsule
3 main sections of the renal tubule are the
proximal convoluted tubule (PCT), the nephron loop, and distal convoluted tubule (DCT)
To produce urine, nephrons and collecting ducts perform three basic processes
Glomerular Filtration
Tubular reabsorption
Tubular secretion
Glomerular Filtration
the first step of urine production- blood pressure forces water and most solutes in blood plasma across the wall of glomerular capillaries
Blood, plasma & dissolved substances get filtered into glomerular (Bowman’s) capsule
Tubular reabsorption
returning most of the filtered water and many of the filtered solutes to the blood, is the second basic function of the nephrons and collecting ducts
Water, ions & substances get reabsorbed from renal tubule into blood
Tubular secretion
the tubule and duct removes substances, such as wastes, frugs, and excess ions, from blood in the peritubular capillaries and transport them into the fluid in the renal tubules
Wastes, drugs & excess ions get secreted from the blood into the renal tubule
The wall of the ureters consisted of 3 layers
Transitional epithelium & Rugae on the inside (mucosa)
Smooth muscle in the middle
Outer layer of areolar connective tissue
The muscular layer of the wall consists of 3 layers of smooth muscle and outer coat called
detrusor muscle & fibrous covering
micturition (the act of urinating) reflex discharges urine from the urinary bladder by means
contraction of the detrusor muscle
relaxation of the internal urethral sphincter muscle
inhibition of the external urethral sphincter
Physical Characteristics of Normal Urine (pH, Albumin, Glucose, RBC, WBC, Ketone bodies, Urobilinogen,
pH 4.6 and 8.0; average 6.0. High-protein diets increase acidity; vegetarian diets increase alkalinity
normal constituent of blood plasma that usually appears in only very small amounts in urine because it is too large to be filtered. The presence of excessive albumin in the urine, albuminuria, indicates an increase in the permeability of filtering membranes due to injury or disease, increased blood pressure, or damage to kidney cells.
glucose usually indicates diabetes mellitus
Haematuria can occur with acute inflammation of the urinary organs as a result of disease or irritation from kidney stones, tumours, trauma, and kidney disease
The presence of white blood cells and other components of pus in the urine, referred to as pyuria, indicates infection in the kidneys or other urinary organs
High levels of ketone bodies in the urine, called ketonuria, may indicate diabetes mellitus, anorexia, starvation, or too little carbohydrate in the diet
The presence urobilinogen (breakdown product of haemoglobin) in urine is called urobilinogenuria may be due to haemolytic or pernicious anaemia, infectious hepatitis, obstruction of bile ducts, jaundice, cirrhosis, congestive heart failure, or infectious mononucleosis
