FINAL EXAM Flashcards
The kidney’s functions are to…
Filter blood by removing wastes via urine.
Remove metabolic wastes and foreign substances.
Regulate plasma’s volume/MAP, ion composition, osmoloarity, and pH.
Blood enters the _________ and branches into arterioles which feed individual __________. Residual blood exits the ________.
renal artery
nephrons
renal vein
Any tubular filtrate not reabsorbed back into the bloodstream is sent to the ________ via the _______.
bladder
ureter
Basic renal exchange process involves what 4 processes?
Glomerular filtration
Reabsorption
Secretion
Excretion
Filtration involves what units of the kidney?
Glomerulus and Bowman’s capsule.
Reabsorption involves what units of the kidney?
Kidney tubules and peritubular capillaries (back into blood).
Secretion involves what units of the kidney?
Peritubular capillaries and nephron tubules.
Excretion involves what units of the kidney?
Nephron tubules (to the body).
What do afferent arterioles bring to the kidney?
Bring in blood to be filtered.
Smooth muscle in the afferent/efferent arterioles vasoconstrict to help regulate what two processes?
Blood flood and glomerular filtration rate.
Fenestrations in the glomerulus allow for…
Water, ions, and glucose to easily pas through.
Efferent arteriole vasoconstriction can back up blood which leads to _____ glomerular capillary hydrostatic pressure and _____ glomerular filtration rate.
high
high
Afferent arteriole vasoconstriction ______ blood flow through the glomerulus and consequently ______ glomerular filtration rate.
lowers
lowers
Glomerular hydrostatic pressure = what kind of force?
Large pro-filter force.
Glomerular oncotic pressure = what kind of force?
Medium anti-filter force, which is mediated by trapped proteins.
Bowman’s capsule oncotic pressure = what kind of force?
Small pro-filter force.
Boman’s capsule hydrostatic pressure = what kind of force?
Small anti-filter force.
During transient modest disruptions of MAP, like during exercise, ________ maintain a normal glomerular filtration rate.
intrinsic controls
What are the parts of the nephron?
Glomerulus/Bowman’s capsule
Proximal tubule
Loop of Henle
Distal tubule/collecting duct
Molecular movement from tubules back into peritubular capillaries (which are returned to blood) is defined as what?
Reabsorption
Diffusion rate is dictated by what two mechanisms?
Membrane permeability; size and charge. Differential concentration (high to low).
Pumping ATP at either the apical or basolateral membranse can allow…
passive transport to occur at the other membrane.
Normal plasma concentrations of glucose can be fully reabsorbed back into capillaries via…
basolateral glucose transport protein located on the promixal tubule.
What happens in people with diabetes mellitus, when extra high glucose concentrations occur and the transporter is saturated?
Glucose doesnt ger reabsorbed so it is excreted in the urine.
Used to do “taste tests”
If a solute is pumped out, what happens to water?
Water follows the solute.
True or False: water actively flows across kidney membranes.
False: it passively moves.
Where does unregulated reabsorption occur?
Proximal tubule (the mass reabsorber).
Where does regulated reabsorption occur?
Distal tubule.
Water and sodium are often reabsorbed.
What are some of the important characteristics of proximal tubule epthelium?
Leaky tight junctions.
Brush border for larger surface area.
Mitochondria.
H+ secreted into it (from peritubular capillaries).
True or false: more glucose is reabsorbed in the proximal tubule than sodium.
True
70% Na+
100% Glucose
The loop of henle produces ___________________ to allow fine control of urine volume in subsequent collecting duct.
medullary osmotic gradient
What are the differences between the descending loop of henle vs. the ascending loop of henle?
Descending is permeable to water, and does not transport ions.
Ascending is impermeable to water, and has a Na+/K+/Cl- cotransporter.
What are some of the important characteristics of the distal tubule and collecting duct epithelium?
Tight junctions.
Hormones regulate reabsorption like ADH and Aldosterone.
Secreation of K+ and H+ occurs in the distal tubule.
H2O reabsorption in the collectein duct is regulated via what hormone?
ADH
What is the difference between diabetes mellitus and diabetes insupidus?
Diabetes insipidus = no AHD to conserve water.
Diabetes mellitus = uncontrollable insulin production.
When blood volume is low (blood osmolarity high) ADH is released from the brain causing what?
Aquaporin insertion into the collecting duct membrane.
What is the function of aquaporins in the kidney?
To allow water to leave the tubular fluid down its concentration gradient back into the blood stream.
Conserves water.
Control of urinary water excretion in the distal tubule is instrumental in regulating what two mechanisms?
Plasma volume/MAP and osmolarity.
How is Na+ reabsorbed in the distal tubule?
Na+ is actively pumped across the basolateral membrane via Na+/K+ ATPase.
Na+ moves across apical membrane by channels or cotransport.
What happens when aldosterone is released from the adrenal cortex?
Aldosterone crosses the plasma membrane and binds to the cytosolic receptor, which increases the number of Na+/K+ pumps on the basolateral membrane and Na+ and K+ channels on the apical membrane.
What is aldosterone secretion regulated by?
Renin/angiotensin system.
Juxtamedullary apparatus contains specialized kidney cells that help regulate what two mechanisms?
Blood volume and MAP.
What do juxtamedullary granular cells secrete?
Protease renin.
Involved in Na+ reabsorption and MAP regulation.
When MAP declines, ________________ system can kick in to increase MAP back to set point level.
Renin/angiotensin
Fluid remaining in the collecting duct drains to the….
minor/majoy calyx cavities and onto the ureter.
What is micturition (urination) mediated by?
spinal cord reflex.
In the spinal cord reflex that mediates micturition, what happens when the parasympathetic system is activated?
Causes contraction of detrusor muscle.
In the spinal cord reflex that mediates micturition, what happens when the sympathetic system is inhibited?
Relaxes the internal sphincter, causes urine to escape.
Blood/body pH regulation occurs via what three mechanisms?
Buffering of hydrogen ions
Respiratory compensation
Renal compensation
What is acidosis?
Depression of the nervous system.
Confusion, coma, and death.
Too many H+ ions.
What is alkalosis?
Hyper-excitability of neruons.
Too many OH- ions.
Which of the three mechanisms is the quickest defense against changes in pH?
Buffering
True or false: Buffering completely gets rids of H+ ions.
False; it only sequesters, can’t completely get rid of it.
What is the most important extracellular buffer?
Bicarbonate
What are some examples of intracellular buffers?
Proteins and phosphates
How does the respiratory system help regulate blood pH?
As H+ levels increase, ventilation increases to get rid of CO2. This in turn shifts the equation to the left, and lowers H+.
What happens in renal compensation in the distal tubule?
Distal tubules secrete H+ and reabsorb HCO3-.
HCO3- can also be synthesizes (from glutamine) in time of severe acidosis.
What is respiratory acidosis?
Hypoventilation.
Build up on CO2.
What is respiratory alkalosis?
Hyperventilation.
Too little CO2.
What is metabolic acidosis?
Decrease in pH through something other than carbon dioxide issues.
What are some causes of metabolic acidosis?
High protein diet - amino acids. High fat diet - keto-acids from fat breakdown. Heavy exercise - lactic acids. Severe diarrhea - loss of bicarbonate. Renal dysfunction
What is metabolic alkalosis?
Increase in pH through something other than carbon dioxide issues.
What are some causes of metabolic alkalosis?
Excessive vomiting - loss of hydrogen ions.
Consumption of alkaline products - baking soda.
Renal dysfunction.
pH problems are either causes by ________ or _________ problems.
respiratory
metabolic
What organs in the GI tract are involved in digestion?
Mouth, stomach, small intestine.
What organs in the GI tract are involved in absorption?
Small and large intestine.
What organs in the GI tract are involved in secretion?
Salivary glands, stomach, pancreas, small intestine, and liver.
During chewing, _________ begins to digest carbohydrates, and ____________ begins to digest lipids.
salivary amylase
lingual lipase
Smooth muscle contraction allows movement of GI contents through…
Segmentation (mixes contents) and peristalsis (propels contents forward).
Smooth muscle contraction in the proximal segment ________ while the distal segment ________.
contracts
relaxes
Pacemaker cells within the GI system initiate…
Depolarization and consequent smooth muscle contraction (segmentation and peristalsis).
In the GI system, the autonomic nervous system (P/S) modulates…
Parasympathetic: depolarization, increasing contraction/motility.
Sympathetic: hyperpolarizes.
The stomach secretes gastric juice (HCL and proteases) in order to…
degrade food bolus into chyme, which is slowly released int o the small intestine.
What is the pyloric sphincter’s function?
Regulates passage of chyme between stomach and small intestine.
Stomach gastric pits secrete _________ and ______.
Pepsinogen (from chief cells)
Acid (from parietal cells)
The stomach’s low pH of 2 is necessary for…
activating pepsinogen into pepsin, which initiates digestion of ingested proteins.
True or false: the stomach is the primary site of digestion and absorption.
False: it is the small intestine.
Pancreatic juice enters which part of the small intestine?
Duodenum
Liver secreted bile enters which part of the small intestine?
Duodenum
What is the function of bile salts?
Emulsification: increase surface area of lipid droplets by breaking large droplets into several small droplets.
What is an example of an endocrine molecule that the pancreas secretes? What is the function?
Beta-Islet cell.
Secrete insulin into the blood stream, which causes glucose to be taken into the cells.
What is an example of an exocrine molecule that the pancreas secretes? What is the function?
Acinar cells.
Produces pancreatic juice, which is rich in bicarbonate (neutralizes chyme) and multiple enzymes stores in zygomen granules that can degrade all four macromolecules (amylase, lipases, proteases, nucleases).
What characteristic/s of the small intestine increase the surface area?
Villi
Microvilli that form a “brush border”
Absorbed nutrients travel in blood to _______ for processing before entering general circulation.
Liver
Liver functions to process what four nutrients?
Glucose - glycogen
Lipids - lipoproteins
LDL - bad cholesterol
HDL - good cholesterol
What are the liver’s other functions, besides processing nutrients?
Bile synthesis.
Waste/toxins elimination.
Plasma protein and hormone synthesis (albumin and angiotensinogen).
True or false: polysaccharide digestion begins in the mouth and finishes in the small intestine.
True, salivary amylase acts in the mouth to break the polysaccharide down.
Are polysaccharides digested in the stomach?
No, the low pH of the stomach inhibits starch digestion.
Indigestible polysaccharides, like cellulose, pass through the G.I. as…
fiber
Monosaccharides are absorbed into…
brush border apical membrane of the small intestine.
_________ and _________ exist on the brush border of the small intestine to facilitate digestion of acids and proteins.
Nucleases
peptidases
True or false: protein digestion begins in the mouth.
False; it beings in the stomach.
What is the enzyme that breaks down proteins in the stomach?
Pepsin (secreted as pepsinogin).
What does endopeptidases in the small intestine do?
Split polypeptides at interior peptide bonds.
What does exopeptidase in the small intestine do?
Cleave off amino acids from ends of polypeptide.
What are some examples of pancreatic proteases?
Trypsin, chymotrypsin, and carboxypeptidase.
How do pancreatic proteases work in the small intestine?
They are stored as inactive zygomen granules, secreted by exocytosis, and activated by proteolysis.
What are some examples of brush border proteases?
Enterokinase, activates trypsin
Amino acids are absorbed across small intestine apicap membrane by ____________ and the basolateral membrane by _________.
AA transporters
facilitated diffusion.
How are lipids digested absorbed in the GI tract, since they are not water soluble?
Lipases are water soluble and can only act on lipid molecules near fat droplet edge (on top of chyme).
Fatty acid monomers absorb into epithelial cells or form micelles, which…
continue to release lipids for absorption.
Small intestine cells remanufacture triglycerides in the __________ from incoming fatty acids.
Smooth ER
Once the smooth ER remanufactures triglycerides, the golgi apparatus further packages those triglycerides into ___________.
chylomicrons
Chylomicrons are too large to directly access capillaries, instead they….
enter the lymph system first.
Chylomicrons are a type of __________.
Lipoprotein
What is the function of lipoproteins?
Transport lipids/cholesterol around the body via the bloodstream.
The liver modified lipoproteins through…
The ratio of lipid/protein.
LDL = low protein, high lipid content.
HDL = high protein, low lipid content.
Water is absorbed primarily in the _____________.
small intestine.
95%
What is the function of the large intestine?
Reabsorb some water and vitamins.
Concentrate/store indigestible feces until elimination.
What are the functions of the endocrine system?
Communicates and helps regulate body functions like blood glucose levels, blood volume, cell metabolism, and reproduction.
Uses hormones to regulate body functions, and is secreted into the blood stream.
What is a secondary endocrine organ?
Kidney
What is the kidney’s function in the endocrine system?
Secretes renin.
Stimulates aldosterone secretion indirectly via the renin-angiotensin system.
What are some examples of primary endocrine organs?
Hypothalamus, anterior pituitary gland, posterior pituitary gland, adrenal medulla, pancreas, thyroid gland, and adrenal cortex.
Insulin travels in the bloodstream to promote…
An absorptive state; glucose and amino acid uptake into cells and glycogen synthesis.
True or false: the brain uses high affinity GLUT transporters that are regulated by insulin.
False: GLUT transporters are NOT regulated by insulin.
When insulin travels in the bloodstream, what happens to GLUT4?
It is inserted into the plasma membrane of adipose and skeletal muscle cells.
How is GLUT4 insertion stimulated?
Insulin secretion
Exercise
What is the difference between type 1 and type 2 diabetes mellitus?
Type 1 = juvenile onset, the individual is autoimmune against pancreatic beta islet cells.
Type 2 = non-insulin dependent, the individual produces insulin but does not signal properly (associated with obesity).
What are the functions of glucagon?
Oppose the effects of insulin - increases blood glucose levels.
Stimulates glycogenolysis in liver and the release of glucose back into the bloodstream.
Stimulates lipolysis in adipose tissue and release of fatty acids into bloodstream.
The hypothalamus and pituitary gland release many hormones to regulate what body systems?
Blood volume, cell metabolism, growth, reproduction, and stress response.
The hypothalamus connects to the pituitary gland in what two ways?
Posterior = direct neural connection Anterior = bloodstream
The anterior pituitary hormones affects multiple downstream organs, like…
Adrenal gland, gonads, thyroid.
The thyroid gland releases the thyroid hormone which is derived from ________ and ________.
tyrosine
iodine
What are the functions of the thyroid hormone?
Modulates cellular metabolism and protein synthesis rates.
Increases appetite, GI nutrient adsorption, and glucose utilization (metabolism).
Increases heart rate and stroke volume, breathing rates, mitochondrial activity, and temperature (cardiovascular).
Increase growth rate and neuron development.
What are common symptoms of hypothyroid disease?
Fatigue, weight gain, feeling “cold,” bradycardia, depression, goiter.
What are common symptoms of hyperthyroid disease?
Nervousness, irritability, tachycardia, tremors.
Bulging eyes.
Luteinizing hormone and follicle stimulating hormone travels though the blood stream to affect ________.
Gonads (ovaries and testicles).
In males, FSH signals _________ to stimulate sperm growth/development.
Sertoli cells
Leutinizing hormone signals Leydig Cells to synthesize/secrete ____________.
testosterone
What are the functions of testosterone?
Facilitates sperm development, development of masculine characteristics, and promotes male sex drive.
In females, the first meiotic division occurs prior to _________.
ovulation
In females, the second meiotic division occurs just after __________.
fertilization
Oocyte maturation is regulated via what hormones?
FSH, LH, and estrogen
