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38 Cards in this Set
- Front
- Back
excretory system |
serves many functions, including the regulation of blood pressure, blood osmolarity, acid-base balance and removal of nitrogenous wastes |
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kidney |
produces urine, which dumps into the ureter at the renal pelvis; contains a cortex and a medulla; each one has a hilum, which contains a renal artery, renal vein and ureter; contains a portal system with two capillary beds in series |
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bladder |
where urine is collected until it is excreted |
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urethra |
what urine is excreted through |
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afferent arterioles |
blood from the renal artery flows into these; these form glomeruli in Bowman's capsule (the first capillary bed of the kidney) |
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efferent arteriole |
blood flows through this to the vasa recta, which surround the nephron (the second capillary bed of the kidney), before leaving the kidney through the renal vein
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detrusor muscle |
muscular lining of the bladder; under parasympathetic control; also has two muscular sphincters (internal urethral sphincter and external urethral sphincter) |
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internal urethral sphincter |
consists of smooth muscle and is under involuntary (parasympathetic) control |
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external urethral sphincter |
consists of skeletal muscle and is under voluntary control |
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kidney participates in solute movement through these three processes |
filtration, secretion, and reabsorption |
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filtration |
the movement of solutes from blood to filtrate at Bowman's capsule; the direction and rate of filtration is determined by Starling forces, which account for the hydrostatic and oncotic pressure differentials between the glomerulus and Bowman's space |
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secretion |
the movement of solutes from blood to filtrate anywhere other than Bowman's capsule |
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reabsorption |
movement of solutes from filtrate to blood |
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proximal convoluted tubule (PCT) |
segment of the nephron; site of bulk reabsorption of glucose, amino acids, soluble vitamins, salts and water; also site of secretion for hydrogen ions, potassium ions, ammonia and urea |
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descending limb of the loop of Henle |
segment of the nephron; permeable to water but not salt; therefore, as the filtrate moves into the more osmotically concentrated renal medulla, water is reabsorbed from the filtrate; the vasa recta and nephron flow in opposite directions, creating a countercurrent multiplier system that allows maximal reabsorption of water |
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ascending limb of the loop of Henle |
segment of the nephron; permeable to salt but not water; therefore, salt is reabsorbed both passively and actively; the diluting segment is in the outer medulla; because salt is actively reabsorbed in this site, the filtrate actually becomes hypotonic compared to the blood |
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distal convoluted tubule (DCT) |
segment of the nephron; responsive to aldosterone and is a site of salt reabsorption and waste product excretion, like the PCT |
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collecting duct |
segment of the nephron; responsive to both aldosterone and antidiuretic hormone and has variable permeability, which allows reabsorption of the right amount of water depending on the body's needs |
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aldosterone |
a steroid hormone regulated by the renin-angiotensin-aldosterone system that increases sodium reabsorption in the distal convoluted tubule and collecting duct, thereby increasing water reabsorption; the results in an increased blood volume (and pressure), but no change in blood osmolarity |
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antidiuretic hormone (ADH or vasopressin) |
a peptide hormone synthesized by the hypothalamus and released by the posterior pituitary; its release is stimulated not only by low blood volume but also by high blood osmolarity; it increases the permeability of the collecting duct to water, increasing water reabsorption; this results in an increased blood volume (and pressure) and a decreased blood osmolarity |
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selective reabsorption or secretion of bicarbonate or hydrogen ions |
how the kidney can regulate pH |
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three major layers of the skin |
epidermis (top) dermis hypodermis (subcutaneous layer) |
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five layers of the epidermis |
stratum corneum (top) stratum lucidum stratum granulosum stratum spinosum stratum basale |
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stratum basale |
contains stem cells that proliferate to form keratinocytes |
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keratinocyte nuclei |
lost in the stratum granulosum and many thin layers form in the stratum corneum |
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melanocytes |
produce melanin |
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melanin |
protects the skin from DNA damage caused by ultraviolet radiation; it is passed to keratinocytes |
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Langerhans cells |
special macrophages that serve as antigen-presenting cells in the skin |
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two layers of the dermis |
papillary layer (top) reticular layer |
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Merkel cells |
sensory cells located in the dermis; respond to deep pressure and texture |
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free nerve endings |
sensory cells located in the dermis; respond to pain |
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Meissner's corpuscles |
sensory cells located in the dermis; respond to light touch |
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Ruffini endings |
sensory cells located in the dermis; respond to stretching |
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Pacinian corpuscles |
sensory cells located in the dermis; respond to deep pressure and vibrations |
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postganglioninc cholinergic sympathetic neurons |
innervate sweat glands |
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vasodilation |
cooling mechanism |
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piloerection |
warming mechanism in which arrector pili muscles contract causing hairs to stand on end (trapping a layer of warmed air around the skin) |
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vasoconstriction |
another warming mechanism |