Test 3: Respiratory and Urinary Systems Flashcards

Question

3 Smaller, Paired Cartliages in Larynx

Answer 1

1. Arytenoid cartilages (2): posterior to thyroid cartilage 2. Corniculate cartilages (2): attached to arytenoid cartilages like a pair of little horns 3. Cuneiform cartilages (2): support soft tissue between arytenoids and epiglottis

Answer 2

=Ligaments suspends larynx from hyoid and hold it together - Types: 1. Thyrohyoid ligament suspends it from hyoid 2. Cricotracheal ligament suspends trachea from larynx 3. Intrinsic ligaments hold laryngeal cartilages together

Answer 3

=Interior wall has two folds on each side that extend from thyroid cartilage in front to arytenoid cartilages in back -Superior vestibular folds -Play no role in speech -Close the larynx during swallowing Inferior vocal cords -Produce sound when air passes between them -Contain vocal ligaments -Covered with stratified squamous epithelium -Suited to endure vibration and contact -Glottis—the vocal cords and the opening between them

Answer 4

the vocal cords and the opening between them

Answer 5

=Walls of larynx are quite muscular - Deep intrinsic muscles operate the vocal cords - Superior extrinsic muscles connect larynx to hyoid bone - Elevate the larynx during swallowing - Infrahyoid group

Answer 6

=Intrinsic muscles control vocal cords - Pull on corniculate and arytenoid cartilages causing cartilages to pivot - Abduct or adduct vocal cords, depending on direction of rotation - Air forced between adducted vocal cords vibrates them producing high-pitched sound when cords are taut - Produces lower-pitched sound when cords are more slack

Answer 7

- Adult male vocal cords, when compared to female cords - Usually longer and thicker - Vibrate more slowly - Produce lower-pitched sound

Answer 8

determined by the force of air passing between the vocal cords

Answer 9

Vocal cords produce crude sounds that are formed into words by actions of pharynx, oral cavity, tongue, and lips

Answer 10

=Trachea (windpipe)—a rigid tube about 12 cm (4.5 in.) long and 2.5 cm (1 in.) in diameter - Anterior to esophagus - Supported by 16 to 20 C-shaped rings of hyaline cartilage that reinforce trachea and prevent collapse during inhalation - Opening in rings faces posteriorly toward esophagus - Trachealis muscle spans opening in rings - Gap in C allows room for the esophagus to expand as swallowed food passes by - Contracts or relaxes to adjust airflow

Answer 11

=Inner lining of trachea is ciliated pseudostratified columnar epithelium - Composed mainly of mucus-secreting cells, ciliated cells, and stem cells - Mucociliary escalator: mechanism for debris removal - Mucus traps inhaled particles - Upward beating cilia drives mucus toward pharynx where it is swallowed

Answer 12

=connective tissue beneath the tracheal epithelium -Contains lymphatic nodules, mucous and serous glands, and the tracheal cartilages

Answer 13

=outermost layer of trachea -Fibrous connective tissue that blends into adventitia of other organs of mediastinum

Answer 14

- Trachea forks at level of sternal angle - Carina: internal medial ridge in the lowermost tracheal cartilage - Directs the airflow to the right and left

Answer 15

=to make a temporary opening in the trachea and insert a tube to allow airflow - Prevents asphyxiation due to upper airway obstruction - Inhaled air bypasses the nasal cavity and is not humidified - If left for long, will dry out mucous membranes of respiratory tract - Become encrusted and interfere with clearance of mucus from tract, thereby promoting infection

Answer 16

- Base: broad concave portion resting on diaphragm - Apex: tip that projects just above the clavicle - Costal surface: pressed against the ribcage - Mediastinal surface: faces medially toward the heart - Hilum—slit through which the lung receives the main bronchus, blood vessels, lymphatics, and nerves - These structures near the hilum constitute the root of the lung

Answer 17

=Lungs are crowded by adjacent organs; they neither fill the entire ribcage, nor are they symmetrical 1. Right lung - Shorter than left because liver rises higher on the right - Has three lobes—superior, middle, and inferior—separated by horizontal and oblique fissure 2. Left lung - Tall and narrow because the heart tilts toward the left and occupies more space on this side of mediastinum - Has indentation—cardiac impression - Has two lobes—superior and inferior separated by a single oblique fissure

Answer 18

=a branching system of air tubes in each lung -From main bronchus to 65,000 terminal bronchioles 1. Main (Primary) 2. Lobar (Secondary) 3. Lobar (Tertiary)

Answer 19

=supported by C-shaped hyaline cartilage rings 1.Right -Rt. main bronchus is a branch 2 to 3 cm long, arising from fork of trachea -Right bronchus slightly wider and more vertical than left Aspirated (inhaled) foreign objects lodge in the right main bronchus more often than in the left 2.Left -Lt. main bronchus is about 5 cm long Slightly narrower and more horizontal than the right

Answer 20

=supported by crescent-shaped cartilage plates Three rt. lobar (secondary) bronchi: superior, middle, and inferior One to each lobe of the right lung Two lt. lobar bronchi: superior and inferior One to each lobe of the left lung

Answer 21

=supported by crescent-shaped cartilage plates - 10 on right, 8 on left - Bronchopulmonary segment: functionally independent unit of the lung tissue

Answer 22

On the Segmental Bronchi -functionally independent unit of the lung tissue

Answer 23

=are lined with ciliated pseudostratified columnar epithelium - Cells grow shorter and the epithelium thinner as we progress distally - Lamina propria has an abundance of mucous glands and lymphocyte nodules (mucosa-associated lymphoid tissue, MALT) - Positioned to intercept inhaled pathogens - All divisions of bronchial tree have a large amount of elastic connective tissue - Contributes to the recoil that expels air from lungs

Answer 24

=Mucosa has a well-developed layer of smooth muscle -Muscularis mucosae contracts or relaxes to constrict or dilate the airway, regulating airflow

Answer 25

=Pulmonary artery branches closely follow the bronchial tree on their way to the alveoli

Answer 26

=Bronchial artery services bronchial tree with systemic blood -Arises from the aorta

Answer 27

-1 mm or less in diameter -Pulmonary lobule: portion of lung ventilated by one bronchiole -Have ciliated cuboidal epithelium -Well-developed layer of smooth muscle -Divides into 50 to 80 terminal bronchioles -Final branches of conducting zone -Measure 0.5 mm or less in diameter -Have no mucous glands or goblet cells -Have cilia that move mucus draining into them back by mucociliary escalator -Each terminal bronchiole gives off two or more smaller respiratory bronchioles

Answer 28

- Have alveoli budding from their walls - Considered the beginning of the respiratory zone since alveoli participate in gas exchange - Divide into 2 to 10 alveolar ducts - End in alveolar sacs: clusters of alveoli arrayed around a central space called the atrium

Answer 29

=150 million alveoli in each lung, providing about 70 m^2 of surface for gas exchange

Answer 30

- Squamous (type I) alveolar cells - Thin, broad cells that allow for rapid gas diffusion between alveolus and bloodstream - Cover 95% of alveolus surface area

Answer 31

- Round to cuboidal cells that cover the remaining 5% of alveolar surface - Repair the alveolar epithelium when the squamous (type I) cells are damaged - Secrete pulmonary surfactant - A mixture of phospholipids and proteins that coats the alveoli and prevents them from collapsing during exhalation

Answer 32

AKA Dust cells - Most numerous of all cells in the lung - Wander the lumens of alveoli and the connective tissue between them - Keep alveoli free from debris by phagocytizing dust particles - 100 million dust cells die each day as they ride up the mucociliary escalator to be swallowed and digested with their load of debris

Answer 33

Each alveolus surrounded by a basket of capillaries supplied by the pulmonary artery Respiratory membrane—thin barrier between the alveolar air and blood

Answer 34

- Squamous alveolar cells - Endothelial cells of blood capillary - Their shared basement membrane

Answer 35

- Gases diffuse too slowly through liquid to sufficiently aerate the blood - Alveoli are kept dry by absorption of excess liquid by blood capillaries - Lungs have a more extensive lymphatic drainage than any other organ in the body - Low capillary blood pressure also prevents rupture of the delicate respiratory membrane

Answer 36

AKA: breathing -consists of a repetitive cycle of inspiration (inhaling) and expiration (exhaling)

Answer 37

=one complete inspiration and expiration

Answer 38

while at rest, effortless, and automatic

Answer 39

deep, rapid breathing, such as during exercise

Answer 40

- Flow of air in and out of lung depends on a pressure difference between air within lungs and outside body - Respiratory muscles change lung volumes and create differences in pressure relative to the atmosphere

Answer 41

- Prime mover of respiration - Contraction flattens diaphragm, enlarging thoracic cavity and pulling air into lungs - Relaxation allows diaphragm to bulge upward again, compressing the lungs and expelling air - Accounts for two-thirds of airflow

Answer 42

-No autorhythmic pacemaker cells for respiration, as in the heart -Exact mechanism for setting the rhythm of respiration remains unknown -Breathing depends on repetitive stimulation of skeletal muscles from brain and will cease if spinal cord is severed high in neck -Skeletal muscles require nervous stimulation Interaction of multiple respiratory muscles requires coordination

Answer 43

-Automatic, unconscious cycle of breathing is controlled by three pairs of respiratory centers in the reticular formation of the medulla oblongata and the pons

Answer 44

1. Ventral respiratory group (VRG) - Primary generator of the respiratory rhythm - In quiet breathing (eupnea), inspiratory neurons fire for about 2 seconds - Expiratory neurons in eupnea fire for about 3 seconds allowing inspiratory muscles to relax - Produces a respiratory rhythm of 12 breaths per minute 2. Dorsal respiratory group (DRG) - Modifies the rate and depth of breathing - Receives influences from external sources

Answer 45

1. Pontine respiratory group (PRG) - Modifies rhythm of the VRG by outputs to both the VRG and DRG - Adapts breathing to special circumstances such as sleep, exercise, vocalization, and emotional responses

Answer 46

-anxiety-triggered state in which breathing is so rapid that it expels CO\_2 from the body faster than it is produced

Answer 47

- As blood CO\_2 levels drop, the pH rises causing the cerebral arteries to constrict - This reduces cerebral perfusion which may cause dizziness or fainting - Can be brought under control by having the person rebreathe the expired CO\_2 from a paper bag

Answer 48

1.Central Chemoreceptors 2.Peripheral Chemoreceptors 3.Stretch Receptors 4.Irritant Receptors 5.

Answer 49

=brainstem neurons that respond to changes in pH of cerebrospinal fluid - pH of cerebrospinal fluid reflects the CO\_2 level in the blood - By regulating respiration to maintain stable pH, respiratory center also ensures stable CO\_2 level in blood

Answer 50

=located in the carotid and aortic bodies of the large arteries above the heart -Respond to the O\_2 and CO\_2 content and the pH of blood

Answer 51

=found in the smooth muscles of bronchi and bronchioles, and in the visceral pleura -Respond to inflation of the lungs -Inflation (Hering-Breuer) reflex: triggered by excessive inflation -Protective reflex that inhibits inspiratory neurons and stops inspiration

Answer 52

=nerve endings amid the epithelial cells of the airway - Respond to smoke, dust, pollen, chemical fumes, cold air, and excess mucus - Trigger protective reflexes such as bronchoconstriction, shallower breathing, breath-holding (apnea), or coughing

Answer 53

=Voluntary control over breathing originates in the motor cortex of frontal lobe of the cerebrum -Sends impulses down corticospinal tracts to respiratory neurons in spinal cord, bypassing brainstem

Answer 54

Breaking point: when CO\_2 levels rise to a point where automatic controls override one’s will

Answer 55

55-60% Water Women is slightly less

Answer 56

About 40 L

Answer 57

=65% intracellular fluid (ICF) =35% extracellular fluid (ECF) -25% tissue (interstitial) fluid -4.8% blood plasma and lymphatic fluid -2% transcellular fluid “catch-all” category -Cerebrospinal, synovial, peritoneal, pleural, and pericardial fluids -Vitreous and aqueous humors of the eye -Bile, and fluids of the digestive, urinary, and reproductive tracts

Answer 58

-Fluid continually exchanged between compartments -Water moves by osmosis -Because water moves so easily through membranes, osmotic gradients never last long -If imbalance arises, osmosis restores balance within seconds, so the intracellular and extracellular osmolarity are equal -If osmolarity of the tissue fluid rises, water moves out of the cell -If it falls, water moves in

Answer 59

=Osmosis from one fluid compartment to another is determined by the relative concentrations of solutes in each compartment -Electrolytes: the most abundant solute particles, by far -Sodium salts in ECF -Potassium salts in ICF -Electrolytes play the principal role in governing the body’s water distribution and total water content

Answer 60

- Great differences between electrolyte concentrations of blood plasma and intracellular fluid (ICF) - Have the same osmolarity (300 mOsm/L) - Concentrations in tissue fluid (ECF) differ only slightly from those in the plasma

Answer 61

1. Sodium 2. Potassium 3. Chloride 4. Calcium 5. Magnesium

Answer 62

1.one of the principal ions responsible for the resting membrane potential -Inflow of sodium through membrane gates is an essential event in depolarizations that underlie nerve and muscle function 2.Principal cation in ECF -Sodium salts account for 90% to 95% of osmolarity of ECF -Most significant solute in determining total body water and distribution of water among fluid compartments -Na^+ gradient is a source of potential energy for cotransport of other solutes such as glucose, potassium, and calcium 3.Na^+–K^+ pump -Important means of generating body heat -Na^+ gradient is a source of potential energy for cotransport of other solutes such as glucose, potassium, and calcium

Answer 63

1. Produces (with sodium) the resting membrane potentials and action potentials of nerve and muscle cells - Most abundant cation of ICF - Greatest determinant of intracellular osmolarity and cell volume 2. Na^+− K^+ pump 3. Essential cofactor for protein synthesis and other metabolic processes

Answer 64

- Most abundant anion in ECF 1. Major contribution to ECF osmolarity 2. Required for the formation of stomach acid (HCl) 3. Chloride shift that accompanies CO\_2 loading and unloading in RBCs 4. Major role in regulating body pH

Answer 65

1. Lends strength to skeleton 2. Activates sliding filament mechanism of muscle contraction 3. Serves as a second messenger for some hormones and neurotransmitters 4. Activates exocytosis of neurotransmitters and other cellular secretions 5. Essential factor in blood clotting

Answer 66

-About 54% of Mg^(2+) is in bone; about 45% in intracellular fluid 1.Most intracellular Mg^(2+) is complexed with ATP Mg^(2+) serves as a cofactor for enzymes, transporters, and nucleic acids 2.Homeostasis -Blood levels of Mg^(2+) Intestinal absorption from food is regulated by vitamin D -Mg^(2+) is lost in feces and urine -Ascending limb of nephron loop can reabsorb Mg^(2+) and mainly determines the extent of retention or loss -Parathyroid hormone governs the rate of reabsorption

Answer 67

separating wastes from body fluids and eliminating them

Answer 68

1.Respiratory system CO\_2, small amounts of other gases, and water 2.Integumentary system Water, inorganic salts, lactic acid, urea in sweat 3.Digestive system Water, salts, CO\_2, lipids, bile pigments, cholesterol, and other metabolic waste 4.Urinary system Many metabolic wastes, toxins, drugs, hormones, salts, H^+, and water

Answer 69

1. Filter blood and excrete toxic metabolic wastes 2. Regulate blood volume, pressure, and osmolarity 3. Regulate electrolytes and acid-base balance 4. Secrete erythropoietin, which stimulates the production of red blood cells 5. Help regulate calcium levels by participating in calcitriol synthesis 6. Clear hormones from blood 7. Detoxify free radicals 8. In starvation, they synthesize glucose from amino acids

Answer 70

1. Urea formation - Proteins amino acids  NH\_2 removed  forms ammonia, - Liver converts ammonia to urea 2. Uric acid - Product of nucleic acid catabolism 3. Creatinine - Product of creatine phosphate catabolism 4. Blood urea nitrogen (BUN)—level of nitrogenous waste in blood - Normal concentration of blood urea is 10 to 20 mg/dL - Azotemia: elevated BUN - May indicate renal insufficiency - Uremia: syndrome of diarrhea, vomiting, dyspnea, and cardiac arrhythmia stemming from the toxicity of nitrogenous waste - Treatment—hemodialysis or organ transplant

Answer 71

any substance that is useless to the body or present in excess of the body’s needs

Answer 72

waste substance produced by the body

Answer 73

Elevated BUN; May indicate renal insufficiency

Answer 74

syndrome of diarrhea, vomiting, dyspnea, and cardiac arrhythmia stemming from the toxicity of nitrogenous waste

Answer 75

- Lie against posterior abdominal wall - Right kidney is slightly lower due to large right lobe of liver - Rib 12 crosses the middle of the left kidney - Retroperitoneal along with ureters, urinary bladder, renal artery and vein, and adrenal glands

Answer 76

-About the size of a bar of bath soap -Lateral surface is convex, and medial is concave with a slit, called the hilum -Receives renal nerves, blood vessels, lymphatics, and ureter

Answer 77

1. Renal fascia immediately deep to parietal peritoneum - Binds it to abdominal wall 2. Perirenal fat capsule: cushions kidney and holds it into place 3. Fibrous capsule encloses kidney protecting it from trauma and infection - Collagen fibers extend from fibrous capsule to renal fascia - Still drop about 3 cm when going from lying down to standing up - Renal parenchyma—glandular tissue that forms urine

Answer 78

glandular tissue that forms urine

Answer 79

1. Outer renal cortex 2. Inner renal medulla - Renal columns—extensions of the cortex that project inward toward sinus - Renal pyramids—6 to 10 with broad base facing cortex and renal papilla facing sinus

Answer 80

one pyramid and its overlying cortex

Answer 81

cup that nestles the papilla of each pyramid; collects its urine

Answer 82

formed by convergence of 2 or 3 minor calyces

Answer 83

formed by convergence of 2 or 3 major calyces

Answer 84

a tubular continuation of the pelvis that drains urine down to the urinary bladder

Answer 85

Kidneys are only 0.4% of body weight, but receive about 21% of cardiac output (renal fraction)

Answer 86

1. Renal Arteries 2. Interlobar arteries: up renal columns, between pyramids 3. .Arcuate arteries: over pyramids 4. Cortical radiate arteries: up into cortex 5. Branch into afferent arterioles: each supplying one nephron 6. Glomerulus - ball of capillaries 7. Efferent Arteries 8. Peritubular Capilliaries (most efferent form here) OR vasa recta (a nework of blood vessels within the renal medullla) 9. Cortical Radiate Veins (from pertiubular arteries) OR Arcuate Veins (from Vasa Recta) 10. Arcuate Veins 11. Interlobar Veins 12. Renal Vein 13. Inferior Vena Cava

Answer 87

Efferemt Arteries either direct blood to: 1. Peritublar Capillaries (most blood forms here) 2. Vasa Recta: a nework of blood vessels within the renal medulla that directly flows into arcuate veins

Answer 88

A.Aorta B.Renal Artery C.Segmental Artery D.Interlobar Artery E.Arcualate Artery F.Cortical Radiate Artery G.Afferent Arteriole H.Glomerulus I.Efferent Arteriole J.Vasa Recta K.Pertibular Capillaries L.Cortical Radiate Vein M.Arcuate Vein N.Interlobar Vein O.Renal Vein P.Inferior Vena Cava

Answer 89

Each kidney has about 1.2 million nephrons

Answer 90

1. Renal corpuscle: filters the blood plasma 2. Renal tubule: long, coiled tube that converts the filtrate into urine

Answer 91

=glomerulus and a two-layered glomerular capsule that encloses glomerulus 1. –Parietal (outer) layer of glomerular capsule is simple squamous epithelium 2. –Visceral (inner) layer of glomerular capsule consists of elaborate cells called podocytes that wrap around the capillaries of the glomerulus \*\*Capsular space separates the two layers of glomerular capsule

Answer 92

–15% of all nephrons –Very long nephron loops, maintain salinity gradient in the medulla and help conserve water –Efferent arterioles branch into vasa recta around long nephron loop

Answer 93

–85% of all nephrons –Short nephron loops –Efferent arterioles branch into peritubular capillaries around PCT and DCT

Answer 94

Nerves and ganglia wrapped around each renal artery 1.Carries sympathetic innervation from the abdominal aortic plexus * Stimulation reduces glomerular blood flow and rate of urine production * Respond to falling blood pressure by stimulating the kidneys to secrete renin, an enzyme that activates hormonal mechanisms to restore blood pressure 2.Kidneys also receive parasympathetic innervation of unknown function

Answer 95

•Kidneys convert blood plasma to urine in four stages 1. Glomerular filtration 2. Tubular reabsorption 3. Tubular secretion 4. Water conservation

Answer 96

=the fluid in the capsular space ## Footnote –Similar to blood plasma except that it has almost no protein

Answer 97

=fluid from the proximal convoluted tubule through the distal convoluted tubule –Substances have been removed or added by tubular cells

Answer 98

=fluid that enters the collecting duct –Undergoes little alteration beyond this point except for changes in water content

Answer 99

•Glomerular filtration—a special case of capillary fluid exchange in which water and some solutes in the blood plasma pass from the capillaries of the glomerulus into the capsular space of the nephron

Answer 100

•Almost any molecule smaller than 3 nm can pass freely through the filtration membrane –Water, electrolytes, glucose, fatty acids, amino acids, nitrogenous wastes, and vitamins •Some substances of low molecular weight are bound to the plasma proteins and cannot get through the membrane –Most calcium, iron, and thyroid hormone Unbound fraction passes freely into the filtrate

Answer 101

•Kidney infections and trauma can damage the filtration membrane and allow albumin or blood cells to filter –Proteinuria (albuminuria): presence of protein in urine –Hematuria: presence of blood in the urine •Distance runners and swimmers often experience temporary proteinuria or hematuria –Prolonged, strenuous exercise reduces profusion of kidney –Glomerulus deteriorates under prolonged hypoxia

Answer 102

•process of reclaiming water and solutes from tubular fluid and returning them to blood

Answer 103

•PCT reabsorbs about 65% of glomerular filtrate, removes some substances from blood, and secretes them into tubular fluid for disposal in urine –Prominent microvilli and great length –Abundant mitochondria provide ATP for active transport –PCTs alone account for about 6% of one’s resting ATP and calorie consumption

Answer 104

1.Transcellular route •Substances pass through cytoplasm of PCT epithelial cells and out their base 2.Paracellular route * Substances pass between PCT cells * Junctions between epithelial cells are leaky and allow significant amounts of water to pass through * Solvent drag—water carries a variety of dissolved solutes with it * Reabsorbed fluid is ultimately taken up by peritubular capillaries

Answer 105

•Sodium reabsorption is key –Creates an osmotic and electrical gradient that drives the reabsorption of water and other solutes –Na^+ is most abundant cation in filtrate –Creates steep concentration gradient that favors its diffusion into epithelial cells –Two types of transport proteins in the apical cell surface are responsible for sodium uptake * Symports that simultaneously bind Na^+ and another solute such as glucose, amino acids, or lactate * Na^+–H^+ antiport that pulls Na^+ into the cell while pumping out H^+ into tubular fluid –Sodium is prevented from accumulating in epithelial cells by Na^+–K^+ pumps in the basal surface of the epithelium •Pumps Na^+ out to extracellular fluid –Na^+ is picked up by peritubular capillaries and returned to blood –The Na^+–K^+ pumps (at the base) are examples of primary active transport – they use ATP –The symports on the apical surface are examples of secondary active transport – they do not directly consume ATP, but are dependent on the primary transport Na^+–K^+ pumps at the base of the cell to establish the sodium concentration gradient •Negative chloride ions follow the positive sodium ions by electrical attraction –Various antiports in the apical cell membrane that absorb Cl^- in exchange for other anions they eject into the tubular fluid: K^+–Cl^- symport

Answer 106

* Potassium, magnesium, and phosphate ions diffuse through the paracellular route with water * Phosphate is also cotransported into the epithelial cells with Na^+ * Some calcium is reabsorbed through the paracellular route in the PCT, but most Ca^(2+) reabsorption occurs later in the nephron * Glucose is cotransported with Na^+ by sodium–glucose transport (SGLT) proteins – normally all glucose is reabsorbed * Nitrogenous wastes –Nephron reabsorbs about half of urea in tubular fluid •Concentration remaining in blood is safe –PCT (proximal convolute dtubule) reabsorbs uric acid, but later portions of the nephron secrete it –Creatinine is not reabsorbed – it is passed in urine

Answer 107

* Each day, kidneys reduce 180 L of glomerular filtrate to 1 or 2 L of urine * Two-thirds of water in filtrate is reabsorbed in PCT * Reabsorption of solutes makes the tubule cells and tissue fluid hypertonic to tubular fluid –Water follows solutes by osmosis through both paracellular and transcellular routes •Transcellularly, water uses channels called aquaporins –In PCT, water is reabsorbed at constant rate called obligatory water reabsorption

Answer 108

Channels within tubular reabsortion

Answer 109

* The amount of solute that renal tubules can reabsorb is limited by the number of transport proteins in tubule cells’ membranes * If all transporters are occupied, any excess solute passes by and appears in urine * Transport maximum is reached when transporters are saturated * Each solute has its own transport maximum –Any blood glucose level above 220 mg/dL results in glycosuria

Answer 110

•Peritubular capillaries reabsorb water and solutes that leave the basal surface of the tubular epithelium Reabsorption occurs by osmosis and solvent drag

Answer 111

1. High interstitial fluid pressure due to accumulation of reabsorbed fluid in extracellular space 2. Low blood hydrostatic pressure in peritubular capillaries due to narrowness of efferent arterioles 3. High colloid osmotic pressure in blood due to presence of proteins that were not filtered

Answer 112

renal tubule extracts chemicals from capillary blood and secretes them into tubular fluid

Answer 113

1.Acid–base balance •Secretion of varying proportions of hydrogen and bicarbonate ions helps regulate pH of body fluids 2.Waste removal •Urea, uric acid, bile acids, ammonia, and a little creatinine are secreted into the tubule 3.Clearance of drugs and contaminants •Examples include: morphine, penicillin, and aspirin

Answer 114

•generate salinity gradient that enables collecting duct to concentrate the urine and conserve water

Answer 115

–Thick segment reabsorbs 25% of Na^+, K^+, and Cl^- in filtrate •Ions leave cells by active transport and diffusion –NaCl remains in the tissue fluid of renal medulla –Water cannot follow since thick segment is impermeable –Tubular fluid very dilute as it enters distal convoluted tubule

Answer 116

•Fluid arriving in the DCT still contains about 20% of the water and 7% of the salts from glomerular filtrate –If this were all passed as urine, it would amount to 36 L/day •DCT and collecting duct reabsorb variable amounts of water and salt and are regulated by several hormones –Aldosterone, atrial natriuretic peptide, ADH, and parathyroid hormone

Answer 117

1.Principal cells * Most numerous * Have receptors for hormones * Involved in salt and water balance 2.Intercalated cells •Involved in acid–base balance by secreting H^+ into tubule lumen and reabsorbing K^+

Answer 118

* The kidney eliminates metabolic wastes from the body, but prevents excessive water loss * As the kidney returns water to the tissue fluid and bloodstream, the fluid remaining in the renal tubules passes as urine, and becomes more concentrated

Answer 119

* Collecting duct (CD) begins in the cortex where it receives tubular fluid from several nephrons * CD runs through medulla, and reabsorbs water, making urine up to four times more concentrated * Medullary portion of CD is more permeable to water than to NaCl * As urine passes through the increasingly salty medulla, water leaves by osmosis, concentrating urine

Answer 120

body’s state of hydration

Answer 121

•drinking large volumes of water will produce a large volume of hypotonic urine –Cortical portion of CD reabsorbs NaCl, but it is impermeable to water –Salt is removed from the urine but water stays in -Urine concentration may be as low as 50 mOsm/L

Answer 122

=production of hypertonic urine ## Footnote –Urine becomes scanty and more concentrated –High blood osmolarity stimulates posterior pituitary to release ADH and then an increase in synthesis of aquaporin channels by renal tubule cells –More water is reabsorbed by collecting duct –Urine is more concentrated

Answer 123

=GFR will be low –Filtrate moves more slowly and there is more time for reabsorption –More salt removed, more water reabsorbed, and less urine produced

Answer 124

•The ability of kidney to concentrate urine depends on salinity gradient in renal medulla –Four times more salinity in the renal medulla than the cortex \*\*\*Nephron loop acts as countercurrent multiplier (Countercurrent system—formed by blood flowing in opposite directions in adjacent parallel capillaries) - Vasa recta—capillary branching off efferent arteriole in medulla , gives the salt back and does not subtract from the osmolarity of the medulla - Multiplier: continually recaptures salt and returns it to extracellular fluid of medulla which multiplies the osmolarity of adrenal medulla –Countercurrent : because of fluid flowing in opposite directions in adjacent tubules of nephron loop

Answer 125

1.Fluid flowing downward in descending limb –Passes through environment of increasing osmolarity –Most of descending limb very permeable to water but not to NaCl –Water passes from tubule into the ECF leaving salt behind –Concentrates tubular fluid to 1,200 mOsm/L at lower end of loop 2.Fluid flowing upward in ascending limb –Impermeable to water –Reabsorbs Na^+, K^+, and Cl^- by active transport pumps into ECF –Maintains high osmolarity of renal medulla –Tubular fluid becomes dilute: 100 mOsm/L at top of loop

Answer 126

•Recycling of urea adds to high osmolarity of deep medulla –Lower end of collecting duct is permeable to urea but neither thick segment of loop nor DCT is permeable to urea –Urea is continually cycled from collecting duct to the nephron loop and back –Urea remains concentrated in the collecting duct and some of it always diffuses out into the medulla adding to osmolarity

Answer 127

## Footnote •glomerulus receives feedback on the status of downstream tubular fluid and adjusts filtration rate accordingly –Regulates filtrate composition, stabilizes kidney performance, and compensates for fluctuations in blood pressure –Juxtaglomerular apparatus: complex structure found at the end of the nephron loop where it has just reentered the renal cortex –Loop comes into contact with the afferent and efferent arterioles at the vascular pole of the renal corpuscle

Answer 128

* Sympathetic nerve fibers richly innervate the renal blood vessels * Sympathetic nervous system and adrenal epinephrine constrict the afferent arterioles in strenuous exercise or acute conditions like circulatory shock

Answer 129

* The renin-angiotensin-aldosterone mechanism is a system of hormones that helps control blood pressure and GFR (glomerular filtration rate) * In response to a drop in blood pressure, baroreceptors in carotid and aorta stimulate the sympathetic nervous system * Sympathetic fibers trigger release of renin by kidneys’ granular cells * Renin converts angiotensinogen, a blood protein, into angiotensin I

Answer 130

* In lungs and kidneys, angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II * Angiotensin II—active hormone that increases BP –Potent vasoconstrictor raising BP throughout body –Constricts efferent arteriole raising GFR despite low BP –Lowers BP in peritubular capillaries enhancing reabsorption of NaCl and H\_2 O –Stimulates adrenal cortex to secrete aldosterone, which promotes Na^+ and H\_2 O reabsorption in DCT and collecting duct –Stimulates Na^+ and H\_2 O reabsorption in PCT –Stimulates posterior pituitary to secrete ADH which promotes water reabsorption by collecting duct –Stimulates thirst

Answer 131

•Aldosterone—the “salt-retaining hormone” –Steroid secreted by the adrenal cortex –Triggers for aldosterone secretion are: * When blood Na^+ concentration falls or * When K^+ concentration rises or * There is a drop in blood pressure ® renin release ® angiotensin II formation ® stimulates adrenal cortex to secrete aldosterone

Answer 132

–Acts on thick segment of nephron loop, DCT, and cortical portion of collecting duct * Stimulates reabsorption of Na^+ and secretion of K^+ * Water and Cl^- follow the Na^+ * Net effect is that the body retains NaCl and water –Helps maintain blood volume and pressure * Urine volume is reduced * Urine has an elevated K^+ concentration

Answer 133

•secreted by atrial myocardium of the heart in response to high blood pressure

Answer 134

To reduce blood volume and pressure ## Footnote 1. Dilates afferent arteriole, constricts efferent arteriole: GFR 2. Inhibits renin and aldosterone secretion 3. Inhibits secretion of ADH 4. Inhibits NaCl reabsorption by collecting duct

Answer 135

•secreted by posterior pituitary –Dehydration, loss of blood volume, and rising blood osmolarity stimulate arterial baroreceptors and hypothalamic osmoreceptors –This triggers release of ADH from the posterior pituitary –ADH makes collecting duct more permeable to water –Water in the tubular fluid reenters the tissue fluid and bloodstream rather than being lost in urine

Answer 136

•secreted from parathyroid glands in response to calcium deficiency (hypocalcemia) –Acts on PCT to increase phosphate excretion –Acts on the thick segment of the ascending limb of the nephron loop, and on the DCT to increase calcium reabsorption –Increases phosphate content and lowers calcium content in urine –Because phosphate is not retained, calcium ions stay in circulation rather than precipitating into bone tissue as calcium phosphate -PTH stimulates calcitriol synthesis by epithelial cells of the PCT

Test 3: Respiratory and Urinary Systems Flashcards

(164 cards)