Renal System Flashcards
Glucose
Needed for RBCs to make ATP bc no mitochondria
Essential for CNS to brain
Kidney functions
- make urine
- regulate pH
- gluconeogenesis
- produce an enzyme
- release a hormone, but not an endocrine gland
- maintaining the proper osmolarity through regulating H2O balance
- regulating the quantity and contraction of ions
- maintaining proper plasma volume
- helping maintain the proper acid-base balance
- excreting the end products of bodily metabolism
- excreting any foreign compounds
- producing renin
- producing erythopoietin
- converting vitamin D into its active form
juxamedullary nephron
long-looped nephron important in establishing the medullary vertical osmotic gradient
cortical nephron
most abundant type
type nephrons
Functional unit of the kidneys
Juxamedullary (20%) and cortical (80%)
functional unit
the smallest unit within an organ capable of performing all the organ’s functions
Afferent arteriole
Carries blood going into the glomerulus, receives signal from granular cells
Efferent arteriole
Carries blood coming out of the glomerulus
Bowman’s capsule
Collects the glomerular filtrate
expanded, double-walled “cup” that surrounds the glomerulus to collect fluid-filtered from glomerular capillaries
constriction
decreases blood flow into glomerulus
Glomerulus
A tufts of capillaries that filters a protein into the tubular compound
vasodilation
allows more blood to enter
Glomerular filtration rate (GFR)
The actual rate of filtration, depends on net filtration pressure and glomerular surface area
forces of glomerular filtration
- glomerular capillary blood pressure (the fluid exerted by the blood within the glomerular capillaries)
- plasma coiled osmotic pressure caused by the unequal distribution of plasma proteins across glomerular membrane
- bowman’s capsule hydrostatic pressure (pressure exerted by fluid in initial part of tubule)
Hydrostatic pressure
Required to push fluid through small sites, comes from blood, opposes the filtration of fluid from the glomerulus into bowman’s capsule
Granular cells
Specialized smooth muscle cells, contain many secretory granules, cause afferent arterial to contract when GPR too high
Filtrate passes through 3 layers
- glomerular capillary wall with endothelial cells
- basement membrane with collagen and glycoproteins
- inner layer of bowman’s capsule with podocytes and epithelial cells
podocytes
actin like filaments, contraction or relaxation can decrease or increase the number of filtration slits open in the inner membrane of bowman’s capsule
Autoregulation
- prevents changes in GFR
- abrupt transient changes in blood pressure
What would happen if there was no autoregulation?
- GPR would increase and H2O solutes would be lost needlessly as a result, of the rise in arterial pressure accompanying heavy exercise
- GPR too low, kidneys wouldn’t eliminate enough wastes, excess electrolytes, and other materials that should be exerted
Vasoconstriction
Decreases blood flow into glomerulus
Vasodilation
Allows more blood to enter
Myogenic response
Respiratory that increases strength muscle leading to increase DP and increase GFR and increase in hydrostatic pressure
Mesangial cells
Responsible for myogenic response by vasodilating or constricting due to bp changes to respond to GFR changes
Tubuloglomerular feedback
Produces substances involved in the control of kidney function
Detect the amount of sodium chloride floating past it
Tubuloglomerular feedback
Produces substances involved in the control of kidney function
Detects the amount of sodium chloride floating past it
Proximal tubule
Uncontrolled reabsorption of solutes and secretion of selected substances occur over time, removes glucose and amino acids
lies in the cortex and is highly coiled or convulated
Macula densa
Specialized tubular cells that detect changes in the salt level of fluid floating past them
Transcellular
Reabsorbing something across the cell membrane
Paracellular
Reabsorbed between cells
Primary active transport
Using ATP to move something
Secondary active transport
requires energy and requires transport
tubular reabsorption
selective movement of substances from inside the tubule into the blood
tubular secretion
selective movement of nonfiltered substances from the pertubuler capillaries into the tubuler lumen
urine secretion
the elimination of substances from the body in the urine
what part of the nephron is in the loop of henle?
- thick descending limb
- thin ascending limb
- thick ascending limb
What type of reabsorption is glucose and amino acids?
Transcellular
What type of of reabsorption is Ca2+, Cl- and H2O?
Paracellular
Pathway of filtrate in bowman’s capsule
filtrate goes through the endothelial cells then basal membrane and epithelial cells and podocytes
Pathway of filtrate with tubes
bowman’s capsule
proximal tubule
thick descending limb
thin descending limb
thin ascending limb
thick ascending limb
distal tubule
collecting duct
thin ascending limb
removed H2O and increase solute concentration
carries fluid back to cortex
What type of reabsorption is H2O?
transcellular
What type of reabsorption is the NKCC cotransport
transcellular
What type of reabsorption is Ca2+, H+, Na+ in the thick ascending limb?
paracellular
aquapropins
the pores in the epithelial cells that transport water out
thick ascending limb
removes solutes and decrease solute concentration
how does filtrate move through the nephron (pathway)?
- bowman’s capsule
- proximal tubule
- thick descending limb
- thin descending limb
- thick ascending limb
- distal tubule
- collecting duct
distal tubule
macula densa cells located here and should be a low concentration of solute and a low GFR
located in the cortex
NKCC
secondary active transport
transcellular
Na+, K+, and Cl- reabsorption
passive reabsorption
no energy spent for the substances net movement (all steps in the transepithelial transport of a substance from the tubular lumen to the plasma)
active reabsorption
takes place if any step in the transepithelial transport of a substance requires energy
sodium-potassium
sodium goes out of the cell
potassium goes into the cell
countercurrent exchange
blood and filtrate go in different directions
always have a concentration gradient to maximize solute
co-current exchange
blood and filtrate in same direction
reach equilibrium and no concentration gradient
factors that affect exchange rate
- diameter
- flow rate - slower flow rate, more exchange of solute
- length - longer means greater ability for solute exchange
vasa recta
blood in the nephron
Micturition
Act of urinating
Two stages: filling and voiding
micturition reflex
initiated when stretch receptors within the bladder wall are stimulated
Blood pressure too high
Decrease bp
Vasoconstrict afferent arteriole to increase glomerular filtration rate
Atrial natriuretic peptide factor/hormone
Atrial natriuretic peptide factor
Released by atrial and impacts sodium
- want to lower sodium
- inhibits NKCC cotransport which decreases SV and decreases BP
Hypertension
High bp
Body regulates bp if too high but most causes are isidiopathic and body allows high bp
Henderson hasserbach equation
PH = pka + log(HCO3)/(CO2)
Respiratory acidosis
Increase CO2
Decrease pH
Respiratory acidosis solution
Increase pH by increasing HCO3
Kidneys reabsorb more HCO2
Metabolic acidosis
Decrease HCO3
Decrease pH
High rates of metabolism
Metabolic acidosis solution
Decrease CO2 or ventilating more
Type II fibers rely on glycolysis to make ATP and produce lactic acid
Respiratory alkalosis
Decrease CO2
Decrease pH
Respiratory alkalosis solution
Decrease HCO3 and decrease pH
Reabsorb less bicarbonate ions
Antiport mechanism not activated
Inhibits glutamine getting disposed into HCO3 and H2O
Blood pressure drugs
Lower bp by lowering SV and reabsorbing less Na+
Reabsorb less H2O b/c it gets peed out
Diuretic
therapeutic agent that cause diuresis or increased urinary output and promotes fluid loss from the body
Loop diuretic
Inhibits the reabsorption of sodium in thick ascending limb in loop of henle
Coupled with potassium supplement to prevent heart failure due to loss of K+
Inhibits reabsorption of 2Cl and K+ bc no Na+ as the energy source
Baroreceptors
Located in carotid arteries in the aorta, monitor amount of pressure exerted on blood vessels
Low blood pressure
Increase bp by retaining more H2O, increasing SV
Cardiovascular: increase HR and SV
Hypothalamus: increase thirst and SV
Kidneys: decrease H2O loss and increase H2O retention
Renin-angiotensin system
- liver releases angiotensinogen (inactive)
- kidneys stimulate granular cells to release renin
- renin converts angiotensinogen to angiotensin I
- endothelial cells have enzyme ACE that coverts angiotensin I to angiotensin II
- angiotensin II stimulates posterior pituitary to release ADH and stimulate adrenal gland to release aldosterone
- ADH and aldosterone work together to impact the kidneys in the distal tubule and collecting duct
- aldosterone is a steroid hormone that can gain access to the nucleus to create more protein structures (sodium channels and sodium potassium ATPase pumps) to pump more sodium out that creates a concentration gradient
- ADH causes more aquaporpins inside the cell to move to the tubular lumen side so H2O can follow the solute to reabsorb more H2O and retain more H2O
angiotensinogen
a plasma protein synthesized by the liver and always present in the plasma at high concentration
angiotensin-converting enzyme (ACE)
located in the small pits in the luminal surface of the pulmonary capillary endothelial cells, main stimulus for secretion of the hormone aldosterone from the adrenal cortex
ACE inhibitor drug
block action of ACE
aldosterone receptor blockers (ARBS)
block the binding of aldosterone with its renal receptor
Afferent articles in controlling bp
Control glomerular filtration and vasoconstriction afferent arteriole to put less H2O in kidneys
Vasopressin/ADH
- stored in posterior pituitary
- made in hypothalamus
- increase ADH to retain more H2O
- decrease ADH to lose more H2O
- always being produced and released
- alc and caffeine can decrease ADH secretion by posterior pituitary
intercalated disk
acid base balance
principle cells
site of the action of aldosterone and vasopressin, H2O conserving hormone
aldosterone
increases Na+ reabsorption by the principle cells of distal and collecting tubes
unitary smooth muscle groups
vascular
gastrointestinal
urinary
respiratory
reproductive (pregnant)
multi-unit smooth muscle groups
ocular eye
skin
reproductive (not pregnant)
smooth muscle contraction steps
- L - type voltage gated channel
- Ca2+ binds to calmodulin (calcium modulating protein)
- myosin light chain kinase (MLCK)
- requires Ca2+ to activate and requires ATP for phosphorylation
- allows myosin to bind to actin by phosphorylating myosin head
caldesmon and calpoinin
on thin filament (actin)
keep smooth muscle in a particularly contracted state
vasodilation and vasoconstriction for complex relaxation/contraction
smooth muscle relaxation
stimulated by a neurotransmitter or peripherin
nitrocoxide stimulates GTP which stimulates cGAMP to inhibit the influx of calcium and increase potassium permeability
cGAMP stimulates myosin light chain phosphatase (MLCP) which takes off the phosphate
cardiac and smooth muscle similarities
calcium and ATP needed
cardiac and smooth muscle differences
calcium induced calcium release
skeletal and smooth muscle similarities
calcium and ATP needed
skeletal and smooth muscle differences
- calcium binds to calmodulin to activate MLCK to phsophorylate myosin head (smooth)
- if same number of cross bridges in both, smooth will elicit a stronger contraction because skeletal muscle is straited
- smooth will consume more ATP because myosin head is phosphorylated with ATP
smooth and cardiac muscle similarities
- need calcium to come into the cell
- smooth muscle unitary and cardiac muscle with gap junctions and are electrically connected
smooth and cardiac muscle differences
- calcium to release calcium from sarcoplasmic reticulum
- calcium binds to calmodulin
- smooth muscle not electrically connected
unitary
electrically connected and respond as a single unit to contract
walls of hollow organs or viscera
linked by gap junctions to create a functional syncytium
self- excitable - peace maker potential and slow wave potentials
multi-unit
independently stimulated
neurogenic (nerve produced) - contraction initiated in response to stimulation by nerves supplying the muscle
phasic and only contracts when neurolly stimulated
3 types of smooth muscle filaments
- thick myosin filaments that are longer than those in skeletal muscle
- thin actin filaments that contain tropomyosin but lack troponin
- filaments of intermediate size, which do not directly participate in contraction but are part of the cytoskeleton framework that supports cell shape
phasic smooth muscle
contracts in bursts, triggered by action potentials that lead to increased cystolic Ca2+, walls of hollow organs that push contents through system
tonic smooth muscle
partially contracted at all times, smooth muscle tone, low ventilating potential
factors influencing smooth muscle activity
mechanical stretch
certain hormones
local metabolites
specific drugs
smooth muscle length tension relationship
- develop tension when stretched
- inherently relaxing when streched
latch phenomenon
smooth muscle can maintain tension with less ATP consumption because each cross bridge cycle uses up one molecule of ATP
detrouser muscle
contracts when bladder fills and receives signal from stretch receptors
internal sphincter
smooth muscle, involuntary muscle
when bladder is relaxed, internal sphincter region closes to the bladder outlet
external sphincter
voluntary control, skeletal muscle
inhibit PMC or sensation of wanting to pee, controlled by pre-frontal cortex
reflex control of bladder
bladder fills
stretch receptors
parasympathetic nerve
bladder
bladder contracts
internal sphincter mechanically opens when bladder contracts
urination
voluntary control of bladder with urination
cerebral cortex
motor neuron to external sphincter
external sphincter opens when motor neuron is inhibited
urination
voluntary control of bladder without urination
cerebral cortex
motor neuron to external sphincter
external sphincter remains closed when motor neuron is stimulated
