The Lymphatic System, Respiratory System, and Fluid and Electrolyte Balance
Lymphatic System
The lymphatic system is a network of vessels and tissues that helps to drain excess fluid from the body and filter out waste products. It also plays a role in the immune response.
Lymphatic Vessels
Lymphatic vessels are thin, blind-ended tubes that collect excess fluid from the interstitial spaces (the spaces between cells). These vessels then transport the fluid to lymph nodes, which are small, bean-shaped organs that filter out waste products and bacteria.
Lymphatic Tissue
Lymphatic tissue is found in lymph nodes, as well as in other locations throughout the body, such as the tonsils, spleen, and thymus. Lymphatic tissue contains lymphocytes, which are white blood cells that help to fight infection.
Excess Fluids in Extracellular Space
Excess fluids in the extracellular space can lead to edema, which is a swelling of the tissues. Edema can be caused by a variety of factors, such as heart failure, kidney failure, and liver disease.
Lymph Trunks
There are nine lymph trunks that drain lymph from specific body areas. These trunks are located in the neck, chest, abdomen, and pelvis.
Intestinal and Lumbar Trunks
The intestinal and lumbar trunks drain lymph from the intestines and lower extremities, respectively. These trunks empty into the cisterna chyli, which is a sac-like structure located in the abdomen.
Cisterna Chyli
The cisterna chyli drains lymph from the intestines and lower extremities into the thoracic duct, which is the main lymphatic vessel in the body.
Lymph Drains into Blood
Lymph eventually drains into the bloodstream at the subclavian veins, which are located in the neck.
Lymph Returns to the Heart
The return of lymph to the heart is assisted by valves in the lymphatic vessels, as well as by the contracting muscles of the body.
Endothelial Cells Flap Shut
When the pressure in the interstitial fluid decreases, the endothelial cells that line the lymphatic vessels flap shut, preventing the backflow of lymph.
Lymph Nodes
Lymph nodes are clusters of lymphoid organs that are found in lymphatic vessels. Lymph nodes filter lymph and remove waste products and bacteria.
MALT
MALT (mucosa-associated lymphatic tissue) is a type of lymphoid tissue that is found in the mucous membranes of the body. MALT helps to protect the body from infection.
Specific Clusters of Lymph Nodes
There are specific clusters of lymph nodes located in the axillae (armpits), neck, groin, and abdominal cavity. These clusters of lymph nodes help to drain lymph from the surrounding areas.
Lymph Flows into Node
Lymph flows into a lymph node through afferent vessels. Once the lymph has been filtered, it flows out of the node through efferent vessels.
Lymph Nodes Filter Lymph
Lymph nodes filter lymph and remove waste products and bacteria. This helps to protect the body from infection.
Spleen
The spleen is the largest lymphoid organ in the body. It is located in the upper left quadrant of the abdomen. The spleen filters blood and removes waste products and bacteria.
Thymus
The thymus is a lymphoid organ that is located in the upper chest. The thymus produces T cells, which are a type of white blood cell that helps to fight infection.
Respiratory Tract
The respiratory tract is a series of passages that allow air to enter and exit the lungs. The respiratory tract includes the nose, pharynx, larynx, trachea, and bronchial tree.
Upper Respiratory Tract
The upper respiratory tract includes the nose, pharynx, and larynx.
Lower RT
The lower respiratory tract includes the trachea and bronchial tree.
Alveoli
The alveoli are tiny, air sacs where gas exchange occurs. Gas exchange is the process by which oxygen from the air is exchanged for carbon dioxide from the blood.
Conducting Zone
The conducting zone of the respiratory tract is the portion of the tract that conducts air toward and away from the alveoli.
Respiratory Zone
The respiratory zone of the respiratory tract is the portion of the tract that contains alveoli, where gas exchange occurs.
Respiration
Respiration is the process of gas exchange between the lungs and the blood. Respiration includes pulmonary ventilation, pulmonary gas exchange, gas transport in blood, and tissue gas exchange.
Respiratory System Aids in
The respiratory system aids in a variety of functions, including:
- Producing speech and vocalizations
- Detecting odors
- Helping to expel the contents of the abdominopelvic cavity
- Assisting in the flow of venous blood and lymph in the thoracic and abdominopelvic cavities
- Maintaining acid-base homeostasis
- Assisting in the production of angiotensin-II for maintenance of BP and fluid homeostasis
Nose and Nasal Cavity
The nose and nasal cavity are the first parts of the respiratory tract that air passes through. The nose and nasal cavity warm and humidify inhaled air, filter out debris from inhaled air, and secrete antibacterial substances. The nasal cavity also houses olfactory receptors, which are responsible for the sense of smell.
Ethmoid Bone
The ethmoid bone is a bone that is located in the skull. The ethmoid bone contains the superior and middle conchae, which are two of the three nasal conchae. The inferior concha is the third nasal concha and is located in the maxilla.
Nasal Conchae
The nasal conchae are three scroll-like structures that are located in the nasal cavity. The nasal conchae help to warm and humidify inhaled air, and they also help to filter out debris from inhaled air.
Paranasal Sinuses
The paranasal sinuses are air-filled cavities that are located in the frontal, ethmoid, sphenoid, and maxillary bones. The paranasal sinuses help to warm and humidify inhaled air, and they also help to reduce the weight of the skull.
Vestibule is Lined with Stratified Squamous Epithelium
that resists mechanical stress; posterior to vestibule the epithelium changes to 2 types of mucous membrane: olfactory mucosa & respiratory mucosa (respiratory epithelium)
Rest of nasal cavity is lined w/ respiratory mucosa composed of psuedostratified ciliated columnar epithelium & goblet cells (glands: secrete mucus)
Combo of ciliated epithelium & mucus is specialized for air filtration
Pharynx (throat)- divided into 3 divisions: nasopharynx, oropharynx, & laryngopharynx
Larynx (glottis/voice box)- inspired air enters after leaving laryngopharynx. Keeps food & liquids out of respiratory tract & houses vocal cords
Trachea (windpipe)- begins in inferior neck, extends to mediastinum; rings of hyaline cartilage cover anterior and lateral surfaces
– have C-shape, rigid to support trachea & keep it open(patent), flexible to allow trachea to change diameter during pulmonary ventilation
Carina- last tracheal cartilage ring, forms “hook” that curves to form partial rings that surround 1st branches of bronchial tree
Mucosa of trachea- lined w/ pseudostratified ciliated columnar epithelium & goblet cells
Carina, L or R lung @ hilum; once in lung bronchus branches into bronchial tree, end in tiny alveoli
Primary bronchi- beginning of bronchial treet, divide into L&R branches @ trachea, branch into secondary bronchi, then 10 smaller tertiary bronchi per lung
Primary bronchi- cartilage change from c-shape to complete rings, then irregular plates that are fewer in #, epithelium change from respiratory epithelium in larger bronchi to columnar cells that become progressively shorter in smaller bronchi, smooth muscle increases
Bronchioles- smallest airways in bronchial tree; simple cuboidal epithelium
Terminal bronchioles- branch into 2 or more respiratory bronchioles surrounded by thin layer of smooth muscle, respiratory bronchioles branch into 2 or more alveolar ducts
Alveoli- final destination for inspired air
Type I alveolar cells- squamous cells that make up 90% of cells in alveolar wall. Exceedingly thin, permits rapid diffusion of gases across plasma membrane
Type II- snall cuboidal cells that makeup 10% of cells in alveolar wall. In cytoplasm are precursors to chemicals called “surfactant”
Surfactant- help reduce surface tension on alveoli
Alveolar macrophages- phagocytes derived from cells formed in bone marrow
R&L lungs separated by heart & mediastinum
Lung’s inferior flat base rests on diaphragm while superior apex sits just above clavicle
Hilum- depression on mediastinal surface of lung where primary bronchi, blood & lymphatic vessels & nerves enter&exit the lung
R lung has 3 lobes, L has 2 due to space required for the heart
Bronchopulmonary segments- thin walls of connective tissue , separate lobes of the lung; further divided into dime-sized hexagonal structures called lobules
Each lung has its own pulmonar artery- delivers deoxygenated blood to lung from R ventricle
Each lung has its own pulmonary vein, delivers oxygenated blood to L atrium of heart
Bronchial arteries- supply tissues of lung w/ blood & nutrients
At hilum, parietal pleura turns over on itself to create inner visceral pleura
Pleural membranes secrete a thin layer of serous fluid often called pleural fluid
Pleural fluid- lubricates the lungs as they expand&contract, reducing friction
Pressure-Volume Rship- provides driving force for pulmonary ventilation, gradient is required when additional energy is not used
Boyle’s law- at a constant temp & constant # of gas molecules, the pressure & volume of a gas are inversely related; as volume of a container increases pressure that gas exerts on the container decreases and vice versa
Inspiratory muscles- pectoralis minor & serratus anterior
3 different pressures at work during ventilation- atmospheric, intrapulmonary, intrapleural pressures
3 primary physical factors of respiratory trat & lungs that influence overall effectiveness of pulmonary ventilation- airway resistance, alveolar surface tension & pulmonary compliance
Spirometer- produces a graph that records normal & forced inhalation & exhalation, can measure the following:
Tidal volume (TV)- amount of air in or exhaled during normal, quiet breathing (about 500 ml in a healthy adult)
Inspiratory reserve volume (IRV)- air that can be forcibly inhaled after normal TV inhalation. IRV averages 2100-3300 ml of air depending on gender & body size
Expiratory reserve volume (ERV)- air that can be forcibly exhaled after normal TV exhalation. ERV averages 700-1200 ml of air
Residual volume (RV)- air left in the lungs after exhaling
Inspiratory capacity- total amount of air that can be inhaled after TV (TV+IRV)
Functional residual capacity- amount of air that is normally left in the lungs after a tidal exhalation (ERV+RV)
Vital capacity- calulated as total amount of exchangeable air (air that moves in & out the lungs) (TV+IRV+ERV)
Total lung capacity (TLC)- sum of all 4 pulmonary volumes, total amount of exchangeable & nonexchangeable air in the lungs (IRV+TV+ERV+RV)
Gas exchange- moving oxygen from inhaled into blood & ultimately into cells while also moving CO2 from blood exhalation in the lungs
Pulmonary gas exchange- exchange of gases btw alveoli & blood (O2 diffuses from air in the alveoli into blood
Tissue gas exchange- exchange of gases btw blood in systemic capillaries & body’s cells
Dalton’s law of partial pressures- each gas in a mixture exerts its own pressure so the total pressure of a gas mixture is the sum of partial pressures of its gases – % of gases x total pressure of all gases (Pgas)
Henry’s law- degree to which a gas dissolves in a liquid is proportional to both partial pressure & its solubility in the liquid
Oxygenated blood flows from pulmonary veins to the left atrium of the heart where it is then distributed to the body’s tissues
Quantity of blood in the pulmonary capillaries is aout 75-100ml
Hypoxemia- a low level of O2 in the blood
Hypercapnia- high level of CO2 in the blood
Thickness of the respiratory membrane is the distance that a gas must diffuse; also effects gas exchange efficiency
Ventilation-perfusion matching (coupling)- degree of match between the amount of air reaching the alveoli (ventilation) & the amount of blood flow (perfusion) in the pulmonary capillaries
Factors affecting effeciency of tissue gas exchange include: surface area available for gas exchange, distance over which diffusion must occur, perfusion of the tissue
O2 transport is facilitated by the protein hemoglobin (Hb)
Each heme group contains 1 iron atom that can bind to 1 molecule of O2; each hemoglobin protein can carry 4 O2 molecules
Loading- O2 from alveoli binds to hemoglobin in pulmonary capillaries which converts deoxyhemoglobin (HHb) to oxyhemoglobin (HbO2)
Partially saturated- Hb w/ 1-3 molecules of O2
Fully saturated- Hb w/ 4 molecules of O2
Saturation depends on- amount in the lungs or tissues & tightness w/ which Hb binds O2 (affinity) or bond strength of Hb
When PO2 levels drop fairly low it shows that Hb binds O2 more tightly; increased affinity, enhanced loading in the lungs, facilitation of O2 release
7-10% of total CO2 produced by cellular metabolism is transported to the lungs dissolved in blood plasma
About 20% of total CO2 is transported to the lungs bound to HB as carbaminohemoglobin
Remaining 70% of CO2 is transported in the blood in the form of bicarbonate ions
Carbonic anhydrase (CA)- enzyme in RBCs, catalyzes the rxn of H2O+CO2 into carbonic acid (H2CO3) by the following reversible rxn: CO2+H2O -> H2CO3 -> HCO3+H
Carbonic acid is converted to bicarbonate ion (HCO3) and hydrogen ion (H)
Most of HCO3 diffuses into the blood plasma while H binds to Hb which acts as a buffer, resisting change in pH that would make plasma more acidic
Reverse rxn happens in RBC to move CO2 to alveolus
Bicarbonate ions diffuse into the plasma & many of the H+ ions bind w/ Hb
Hyperventilation- increases CO2 exhaled, decreases PCO2 in blood; less carbonic acid is formed, less hydrogen ions are formed, and pH of blood increases & becomes more basic
Hypoventilation- rate &/or depth of breathing decreases; retention of CO2 & increases in PCO2; more carbonic acid is formed, more H+ ion formation & blood becomes more acidic as pH drops – leads to hypoxemia
Respiratory alkalosis- hyperventilation; lack of CO2 = increase in blood pH
Respiratory acidosis- hypoventilation; increase in CO2 = decrease in blood pH
Dyspnea- shortness of breath
Eupnea- regular breathing
Medulla oblongata- controls ventilation, neurons in medulla influence respiratory rhythm
Respiratory rhythm generator (RRG)- found in medulla oblongata; creates basic rhythm for breathing
Ventral respiratory group (VRG)- anterior & lateral portion of medulla; send impulses to phrenic nerve which innervates the diaphragm & intercostal nerves
Dorsal respiratory group (DRG)- posterior medulla; involved in inhaling; sends impulses down same pathways as VRG
Central chemoreceptors- medullary reticular formation; monitor H+ levels in cerebrospinal fluid (CSF)
VRG- stimulates ventilation
High PCO2 or H+ concentration or both trigger hyperventilation; VRG is stimulated which increases ventilation rate that lowers CO2 & H+ restoring homeostasis
Low PCO2 or H+ concentration or both trigger hypoventilation; VRG is inhibited which decreases ventilation rate that raises CO2 & H+
Peripheral Chemoreceptors- found in carotid arteries & aortic arch, called carotid bodies & aortic bodies
These cells detect changes in arterial blood levels of O2, CO2 & H+ ions
When arterial PO2 falls below 60mm Hg (norm is 100), these chemoreceptors send signals to DRG along the glossopharyngeal (CN IX) & vagus (CN X) nerves; DRG then increases ventilation
Restrictive lung diseases- reduce pulmonary compliance & reduce effectiveness of inhalation by increasing alveolar surface tension & destroying the elastic tissue of the lungs
These diseases decreases IC, VC, & TLC
Common restrictive diseases- idiopathic pulmonary fibrosis, pneumoconiosis, & neuromuscular diseases & chest wall deformities
Obstructive lung diseases- increase airway resistance which decreases efficiency of exhalation
Obstructive diseases include- asthma, chronic bronchitis, & emphysema
Asthma- airways are hyperresponsive to a variety of triggers
Lung cancer- refers to tumors arising from the epithelium that lines the bronchi, bronchioles & alveoli
Kidneys- filter blood to remove waste; found outside & posterior to peritoneal membrane (retroperitoneal)
Adrenal gland- found on superior pole on each kidney
Urine- exits kidneys through the ureters (posterior body wall), ureters empty into bladder on floor of pelvic cavity where urine is stored, urine exits from bladder through urethra
Kidney functions- remove waste, filtering & eliminating metabolic wastes from blood, fluid & electrolyte balance; regulate acid-base balance & BP by conserving or eliminating H+ ions and HCO3- ions
Kidney is held in place and protected by- renal fascia, adipose capsule, renal capsule
Hilum- opening on medial surface of kidney where renal artery, vein, nerves & ureters enter & exit; opens into renal sinus
Front section of kidney- renal cortex, renal medulla, renal pelvis; first two make urine forming portion & pelvis drain urine
Renal columns- extensions of renal cortex
Nephrons- over 1 million are present; renal corpuscle & renal tubule
Renal pyramids- found w/i renal columns; tapers into slender papilla
Papilla- border on minor calyx; 3 to 4 minor calyx drain into major calyx, 2 to 3 major into renal pelvis, ureter
Calyces & renal pelvis found in renal sinus
Blood flow- renal, segmental, interlobal, arculate, interlobular, cortical radiate artery
afferent arterioles, glomerulus, efferent arterioles, peritubular capillaries, form plexus
Blood flow smallest to largest- interlobular, arculate, interlobar, renal veins; renal vein exits from hilum to drain into inferior vena cava
Renal corpuscle- glomerulus & glomerular capsule
Glomerulus- ball of fenestrated capillaries that allow for filtration of blood
Glomerular capsule- visceral layer of podocytes & parietal layer that forms outer wall
Visceral layer made of modified epithelial cells called podocytes who surround glomerular capillaries to form filtration slits
Capsular space- hollow region btw parietal & visceral layers
Renal tubule- new filtrate enters where it can be further modified in proximal, nephron (loop of henle) loop & distal tubules
Proximal tubule- cuboidal epithelial cells w/ microvilli (increase surface area for reabsorption)
Loop of Henle- descending limb (simple squamous epithelial) travel to renal medulla one 180 it is called ascending limb (simple cuboidal)
Distal tubule- simple cuboidal w/o microvilli
Juxtaglomerular apparatus (JGA)- composed of macula densa & JG cells found at ascending limb & dital tubule
JGA- regulatws BP & glomerular filtration rate (GFR)
Cortical nephrons- 80% of nephrons in kidney, renal cortex
Juxtamedullary nephrons- control voume & conc of urine
Nephron loop surrounded by vasa recta that arise from efferent arteriole & drain into interlobular veins
Tubular reabsorption- reclaim H2O & solutes from filtrate & return it to the blood; reclaims water, glucose, amino acids, & electrolytes from tubular fluid then return to blood
Filtration membrane- fenestrated glomerular capillary endothelial cells, basal lamina, podocytes
Glomerular filtration rate (GFR)- amount of filtrate formed by both kidneys in 1 min; 125 ml/min
Hydrostatic pressure- force of a fluid on the wall of its container
Colloid osmotic pressure (COP)- pressure created by proteins (primarily albumin) in the plasma
Net filtration pressure (NFP)- interaction btw hydrotatic & COP
Glomerular hydrostatic pressure (GHP)- determined by systemic BP; measures 50 mmHg; favors filtration into capsular space
Glomerular Colloid Osmotic Pressure (GCOP)- averages 30 mmHg; created by of proteins in plasma
Capsular Hydrostatic Pressure (CHP) averages 10 mmHg; tries to push H20 into glomerular capillaries & opposes filtration
NFP = GHP-(GCOP+CHP)- favors filtration
Myogenic Mechanism- autoregulatory mechanism in blood vesseld by the degree of stretch of vessel wall triggers a reflex that maintains blood flow to tissue
Tubuloglomerular Feedback- negative feedback loop that controls pressure in the glomerulus
Renin-Angiotensin-Aldosterone System (RAAS)- maintains BP 1st & GFR 2nd responding to stim from neurons of SNS, low BP, & stim from macula densa cells in response to low NA+ & chloride ion conc. in filtrate
BP drops- GFR drops, triggers renin release, angiontensinogen, angiontensin 1, angiotensin 2 by ACE enzyme produce in lungs
Ang-2 promotes vasoconstriction of efferent arterioles & systemic blood vessels & promotes reabsorption
ANP- hormone released by heart cells in atria bc of increasing fluid volume that lowers blood volume & BP to reduce workload of heart; ANP increases GFR by dilating afferent & constriction efferent increasing GHP
Renal failure- condition that develops when GFR is less than of 50% of normal, leading to buildup
Pumps- can become saturated where binding sites are filled w/ substances for & have reached their transport maximum (TM)
Proximal Tubule- sodium, chloride, potassium, sulfate & phosphate ions are reabsorbed
Nutrients- glucose, amino acids, lactic acid, & water-soluble vitamins are reabsorbed
Sodium ion reabsorption occurs by facilitated diffusion through ion leak channels of tubule cells apical surface
Reabsorption of organic solutes & ions occurs in first half of proximal tubule
Bicarbonate reabsorption- occurs as result of Na/H antiporter activity – CO2+H2O – H2CO3 – H + HCO3
Obligatory water reabsorption- occurs in second half of proximal tubule
Aquaporin- water channels fond in apical & basolateral cell membranes that increase the reabsorptin of H2O
Secretion in proximal tubule includes ammonium ions, drugs & various nitrogenous wastes
Once filtrate reaches nephron loop 60-70% of H2O & electrolytes & most organic solutes have been reabsorbed & returned to the blood
About 20% of H2O & 25% of NA and chloride ions are reabsorbed here
When filtrate reaches 1st segment of distal tubule, 85% or H2O & 90% of Na ions have been reabsorbed
Aldosterone- (steroid from adrenal cortex) increases reabsorption of Na from filtrate & secretion of K into filtrate
ADH- made by hypothalamus & secreted by posterior pituitary that causes H2O reabsorption & reduces urine output
ANP- stims urinary excretion of Na ions while inhibiting release of aldosterone & ADH = more H2O & Na excretion
Medullary collection system- impermeable to H2O in absence of ADH, permeable to urea
Cells of proximal tubule secrete H ions as a mechanism for reabsorbing bicarbonate ions while cells of distal tubule secrete H ions under direction of aldosterone
When pH decreases/too acidic- enzymes in tubule cells will remove NH2 from amino acid glutamine in cytosol, cells generate 2 ammonia molecules & 2 bicarbonate ions; ammonia secreted & bicarbonate is reabsorbed; ammonia buffering & bicarbonate reabsorption help to raise pH of blood back to normal
When pH increases/too basic- tubule cells reabsorb less bicarbonate ions from filtrate, lowring blood pH as ions excreted in urine
85% of H2O reabsorption is obligatory, leaving behind 15% of H2O that can be adjusted; faculatative H2O reabsorption determines final urine conc
Osmolarity of filtrate- if less H2O is reabsorbed filtrate conc remains low, less than 300 mOsm & results in elimination od dilute urine; if more H2O is reabsorbed filtrate conc remains high, greater than 300 mOsm & results in elimination of more concentrated urine
Concentrated urine- reach nearly 1200 mOsm using release of ADH turns on faculatative H2O reabsorption & medullary osmotic gradient creates an osmotic gradient w/i renal medulla allowing for continued reabsorption of H2O from filtrate
Countercurrent mechanism- creates & maintains the medullary osmotic gradient; countercurrent multiplier system in juxtamedullary nephrons, recycling of urea in medullary collection duct & countercurrent exchanger in the vasa recta
Urine normally contains- water, sodium, potassium, chloride, H ions; phosphates, sulfates, & metabolic wastes like urea, creatinine, ammonia, uric acid, small amounts of bicarbonate, calcium & magnesium ions
Urinalysis- urine color, pH, odor, & specific gravity
Renal clearance- can estimate GFR in mm of plasma/min
Creatinine- measures kidney function
Adult ureter- 20-30 cm long w/ diameter of 3-4 mm begins @ level of 2nd lumbar vertebra, behind peritoneum & empties into bladder; composed of mucosa, muscularis, & adventitia
Bladder- holds 700-800 ml of urine in males, less in females; walls made of mucosa, muscularis (detrusor) & adventitia
Trigone- triangle shaped region on bladder floor, ureter openings found @ posterior corners
Walls of bladder- muscosa contains scattered urethral glands that secrete mucus into urine, muscularis is thinner in the urethra compared to uterus
Female urethra- 4cm, opens to external urethral orifice
Male urethra- 20cm; prostatic, membranous, & spongy (penile) urethras
Mictorition reflex- mediated by PNS when urine fills bladder & stretches walls; stretch receptors in bladder wall are activated & afferent signals are sent to the spinal cord; found in the pons of CNS
Acids- release H+ ions when dissolved in H2O, increasing H+ ion conc of solution; HCl in tummy, H2CO3 in blood, lactic acid made during anaerobic resp
Bases- accept H+ ions or release OH- ions when dissovled in H2O decreasing H+ ion conc in solution; bicarbonate ion (HCO3-)
Low pH- increase in H ion conc (lower than 7 – acidic)
High pH- solution with lower H ion conc (higher than 7 – basic)
TBW- uses 70 kg (154 lb) man as reference; varies based on body fat content, gender, age & amount of fat tissue
Intercellular- makes up about 60% of TBW
Extracellular- made of interstitial fluid & plasma
Hydrostatic gradient- force fluid exerts on walls of its container; causes H2O to move out of compartment w/ higher pressure
Osmotic gradient- force exerted by solutes in fluid; draws H2O into compartment w/ higher solute conc
High hydrostatic pressure dominates at arterial end of blood vessels which pushes H2O out of vessel to interstitial fluid
High osmotic pressure dominates at venous end of blood vessels which pulls H2O lost to interstitial fluid back into vessel
Hypotonic- when ECF is lower to cytosol, cell swells
Hypertonic- when ECF is higher to cytosol, cell shrinks
Obligatory loss- about 500ml of urine
Sensible loss- about 100 ml of feces
Insensible loss- about 600ml from skin, 300ml in exhaled humidified air
Most people lose about 2.5L daily and gain 2.5L daily
Increased ADH- increased ECF & decreased urine
Decreased ADH- decreased ECF & increased urine
Hypotonic hydration (overhydration)- when ECF volume increases, decreasing osmotic pressure = swelling
Na ions conc are kept low w/i cell bc of Na/K pump & low plasma membrane permeability to Na
Increase Na retention- aldosterone & ang-2
Main trigger for RAAS- low bp or low blood volume
ANP- decreases Na & H2O reabsorption
Hypernatremia- dehydration, elevated Na conc
Hyponatremia- overhydration, decreased Na conc
K ions- most abundant intracellular cation
Insulin, aldosterone, & epinephrine stim uptake of K by cells
Hyperkalemia- excess K can cause depolarization of RMP leading to impaired neuromuscular function & life threatening cardiac arrhythmias
Hypokalemia- decreased K conc commonly caused by diuretics, excitable cells are hyperpolarized & less responsive to stim
Ca cations- blood clotting, muscle contraction, nerve function, enzyme activity & signal transduction
Ca is maintained by- bone resorption, renal reabsorption, & intestinal absorption & the 2 hormones PTH & vitamin D (calcitrol)
Hypercalcemia- excess Ca, hyperparathyroidism, excess vitamin D, bone disorders & renal failure; seen in nervous system most obviously
Hypocalcemia- decreased Ca, vitamin D deficiency, ineffective PTH w/ renal failure; neurons become hyperexcitable due to increase in Na permeability
Acidosis- body fluid pH of less than 7.35
Acidemia- refers to low blood pH
Respiratory compensation- increasing ventilation to blow off excess CO2, reducing the conc of carbonic acid & raising blood pH
Renal compensation- increasing reabsorption & regeneration of bicarbonate ions
1st compensatory mechanism- kidneys try to compensate for metabolic acidosis by increassing the excretion of H ions into urine & reabsorbing more HCO3 ions to restore pH balance
Alkalosis- body fluid greater than 7.45
Alkalemia- refers to high blood pH
ABGS- used to assess & monitor a patient’s acid-base balance; measures pH, PCO2 & blood bicarbonate level
Respiratory acidosis- high PCO2 & low pH
Metabolic acidosis- low pH & low HCO3 level
Respiratory alkalosis- high pH & low PCO2; low bicarbonate ion level indicates partial compensation by kidneys
Metabolic alkalosis- shows elevated pH & high HCO3 ion level; high PCO2 levels indicate a respiratory response leading to partially compensated metabolic alkalosis