The urinary system consists of what?
- 2 kidneys
- 2 ureters
- the urinary bladder
- the urethra
Where are the kidneys located?
Retroperitoneal (behind the peritoneum) on either side of the backbone
What helps to hold them in place and cushion the kidneys?
- adipose tissue
- renal fascia
The function of the kidneys?
- form urine
- to excrete waste products
- regulate the volume, electrolytes and pH of the blood and tissue fluid
Outer tissue layer of the kidney, made of renal corpuscles and convoluted tubules
inner tissue layer of the kidneys, made of loop of henle, and collecting tubules and the pyramids
a cavity formed by the expanded end of the ureter within the kidney at the hilus, extensions around the papillae of the pyramids are called calyx which collect urine
The structural and functional init of the kidney,
about 1 million in each kidney
consists of the glomerulus surrounded by the bowmans capsule
Capillary network between an afferent and efferent arteriole
the expanded end of the renal tubule that encloses the glomerulus
the inner layer is made of podocytes (has pores) and is very permeable
contains renal filtrate
Consists of the proximal and distal tubules loop of henle and collecting tubes
arise from the efferent arteriole and surround all parts of of the renal tubule
Blood vessel pathaway in the kidney
Abdominal aorta - renal artery - afferent - glomerulus - efferent - peritubular capillaries - renal vein - inferior vena cava
Formation of urine
- 1 Glomerulus filtration
- 2 Tubular reabsorption
- 3 Tubular secretion
Takes place in the glomerulus, high blood pressure in the glomerulus forces plasma, dissolved materials, small proteins out of the blood into the bowmans capsule == filtrate
Filtration is selectively permeable in terms of ___ ?
what remains in the blood ?
Blood cells and large proteins
Glomerular Filtration Rate
- amount of renal filtrate formed by the kidneys in 1 minute
- 100 - 125 mL per minute
- increased blood increases GFR
- decreased blood decreases GFR
takes place from the filtrate in the renal tubules to the peritubular capillaries
99% of filtrate is reabsorbed only 1% becomes urine
reabsorption of glucose, amino acids, vitamins, and positive ions
a limit to how much can be absorbed
transport of most negative ions, they follow the reabsorption of positive ions
transport of water
follows the reabsorption of sodium
small proteins are engulfed by proximal tubule cells
- Secreted from the adrenal cortex
- increases the reabsorption of NA and K
ADH - Anti diuretic horomone
- Secreted by the pituitary gland
- increases the absorption of H20 into the blood
PTH - parathyroid horomone
- secreted by the parathyroid glands
- increases the absorption of Calcium and
- excretion of phosphate
ANP - Atrial Natriuetic Peptide
- Secreted by the atria of the heart
- decrease the absorption of Sodium
- more sodium and water are excreted in the urine
What do the kidneys excrete if the body fluids are becoming to acidic?
- Hydrogen Ions
- and return Bicarbonate ions to the blood
What do the kidneys secrete if the body tissues are becoming to alkaline?
Bicarbonate ions and return more hydrogen ions to the blood
When the blood pressure becomes to low, these cells secrete what to increase it?
Juxtaglomerular cells JG cells secrete renin
What hormone causes vasoconstriction and increases the secretion of aldosterone?
What do the kidneys secrete in response to hypoxia? This hormone stimulates ____ to increase the production of ____?
- stimulates red bone marrow to produce RBCs
A reservoir for urine?
bladder is located where in females? and males
- females: below the uterus
- males: above the prostate
Smooth muscle layer, a spherical muscle that contracts to expel urine?
how long is the urethra in males? females?
Males: 7-8 in long, passes through prostate and penis; also secretes semen
female: 1- 1.5 in long, anterior to the vagina
involuntary sphincter that is formed by the detrusor muscle fibers around the opening of the urethra
Internal urethral sphincter
Voluntary; skeletal muscle of the pelvic floor -- sphincter?
External urethral sphincter
Stimulus of the urinary reflex?
stretching of the detrusor muscle by accumulating urine in the bladder
the urinary reflex
the measurement of dissolved material in urine
Characteristics of urine:
Amount, color, specific gravity, pH, composition, and nitrogenous wastes
- Amount = 1 - 2 L
- Color = straw or amber
- Specific gravity= 1.010 - 1.025
- pH = 6, range 4.6 - 8
- Composition = 95% water, 5% waste
- Nitrogenous wastes: Urea, creatinine, uric acid
comes from amino acid metabolism
comes from muscle metabolism
Comes from nucleic acid metabolism
glucose in the urine
Protein in the urine
Blood in the urine
Bacteria in the urine
Ketones in the urine
inflammation of the bladder
inflammation of the kidneys