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Deamination
removal of an amino group from an organic compound (protein breakdown)
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urea
- nitrogen waste formed from two molecules of ammonia and one molecule of carbon dioxide
- broken down from ammonia in the liver, it is 100, 000 times less toxic
- expelled as waste from mammals and adult amphibians
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uric acid
- a waste product formed form the breakdown of nucleic acids
- insects, land snails, and many reptiles, including birds mainly excrete uric acid
- largely insoluble in water
- requires more energy to produce then urea but wastes less water
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ureter
A tube that conducts urine from the bladder to the exterior of the body
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cortex
the outer layer of the kidney
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medulla
the area inside of the cortex in the kidney
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renal pelivis
the hollow area where the kidney joins the ureter
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nephron
a functional unit of the kidney
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afferent arteriole
a small branch of the renal artery that carries blood to the glomerulus
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glomerulus
the high-pressure capillary bed that is the site of filtration in the kidney
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efferent arteriole
a small branch of the renal artery that carries blood away from the glomerulus to the peritubular capillaries
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peritubular capillary a member of the network of small blood vessels that surround the tubule of the nephron
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Bowman's capsule
the cuplike structure that surrounds the glomerulus
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proximal tubule
the section of the nephron joining the Bowman's capsule with the loop of Henle
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Loop of Henle
the section of the tubule that carries filtrate from the proximal tubule to the distal tubule
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distal tubule
conducts urine from the loop of Henle to the collecting duct
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collecting duct
a tube that carries urine from nephrons to the renal pelvis
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threshold level
the maximum amount of a substance that can be removed across the nephron
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interstitial fluid
the fluid that surrounds the body cells
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How does the kidney maintain a pH balance?
- the bicarbonate-carbon dioxide buffer system maintains the pH balance
- by excreting excess H+ ions and restoring HCO3- ions to the blood
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Kidneys help...
filter water from the blood and help maintain water balance
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The liver helps...
to eliminate toxic nitrogen groups from the body by deamination
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Urine formation depends on three functions:
filtration, reabsorption, and sectretion
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Secretion is...
the active transport of waste from the blood in the nephron
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Diabetes Mellitus
kidney dysfunction caused by inadequate insulin from islet cells in the pancreas, because of the high concentration of glucose left in the blood water remains in the nephron and is lost with the urine
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Nephritis
- kidney diseases characterized by inflammation of the nephrons
- may lead to irreversible kidney damage and kidney failure
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Kidney stones
- are caused by the precipitation of mineral solutes from the blood
- the sharp-sided stones can be lodged in the renal pelvis or may move down the ureter into the bladder and be passed out of the body with urine (OUCH!)
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Dialysis
- Like a kidney that is properly functioning, a dialysis machine operates on the principles of diffusion and blood pressure in order to restore the proper solute balance.
- Unlike a kidney the dialysis machine cannot perform active transport.
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Filtration
pressure-filtering of body fluids
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reabsorption
reclaiming valuable solutes
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excretion
removing the filtrate from the system
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Where is glucose reabsorbed in the kidney?
into the blood stream at the proximal convoluted tubule into the capillaries
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where is water reabsorbed in the kidney?
in the descending limb if the loop of Henle, the proximal convoluted tubule, and the collecting tubule
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What is not filtered glomerulus?
proteins
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Sodium in the kidney...
- is reabsorbed in the descending limb of Henle and it creates a concentration gradient by loop of Henle
- active transport is required to move sodium
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Are the ascending and descending limbs in the loop of Henle permeable to water?
- the ascending limb is impermeable to water but sodium is actively pumped out to produce a low water potential in medulla
- the descending limb is permeable to water
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Antidiuretic hormone (ADH)
increases water reabsorption in the distal tubules and collecting ducts of the kidney
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Diuretics
inhibit the release of ADH and cause more frequent urination
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Aldosterone
a hormone which increases blood volume and pressure
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If low blood volume and pressure occurs in the kidneys, the kidneys recognize this and...
release renin which tells the adrenal gland to release aldosterone which increases Na+ and H2O reabsorption in the distal tubule
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Cardiac muscle
the involuntary muscle of the heart
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smooth muscle
the involuntary muscle found in the lining of many organs
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skeletal muscle
the voluntary muscle that makes the bones of the skeleton move
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tendon
a band of connective tissue that joins muscle to bone
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antagonistic muscle
a pair of skeletal muscles that are arranged in pairs and that work against each other to make a joint move
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flexor
the muscle that must contract to bend a joint
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extensor
the muscle that must contract to straighten a joint
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sarcolemma
the delicate sheath that surrounds muscle fibres
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mylofilament
a thread of contractile proteins found within muscle fibres
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Two kinds of myofilaments are....
actin and myosin
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creatine phosphate
a compound in muscle cells that releases a phosphate to ADP and helps regenerate ATP supplies in muscle cells
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summation
increased muscle contraction produced by the combination of stimuli
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tetanus
the state of constant muscle contraction caused by sustained nerve impulses
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What are the fast and slow twitch muscle fibres?
- slow-type I
- fast-type IIa
- fast-type IIx
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The energy for muscle contraction is provided by what?
ATP
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Isotonic
having that same solute concentration as another solution
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Osmoconformer
- animals whose body fluids are isotonic with their surroundings and don't regulate their osmolarity
- most marine invertebrates(no backbone) are osmoconformers
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Osmoregulator
- animals that actively adjust their internal water balance to maintain osmotic pressure
- most marine vertebrates and some invertebrates are osmoregulators
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Hyperosmotic
- A condition in which the total amount of solutes (salt) in a solution is greater than that of another solution
- Osmoregulators who live in a hyperosmotic environment have less salt then the environment does
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Hypoosmotic
- a condition in which the total amount of solutes (salt) in a solution is lower than that of another solution
- osmoregulators who live in hypoosmotic environments have more salt than the environment
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