respiratory and urinary review Flashcards
Where is the location of the chemoreceptors most sensitive to changes in pH?
medulla, carotid bodies, and aortic bodies
Are peripheral chemoreceptors more sensitive to changes in oxygen or carbon dioxide?
O2
What force drives the exchange of oxygen and carbon dioxide?
air weighs which creates a pressure gradient between the alveolar air and the capillary
Explain what the phrase ‘air weighs’ means, and why it is important for respiration.
atmospheric air has weight
What is the barometric pressure of dry atmospheric air at sea level?
760mmHg
Explain why it is difficult for humans to climb to high elevations?
because the pressure is lower and the pressure gradient is lower.
What is Fick’s law, and how does it pertain to gas diffusion?
the rate of transfer of a gas (VGas) through a sheet of tissue is proportional to the tissue area (A) and the difference in partial pressure between the two sides (p1-p2) and inversely proportional to the tissue thickness (T)
Vgas= A/T x D (P1-P2)
What would happen to diffusion of oxygen if the alveolar wall thickened?
It would reduce the rate of diffusion
What happens to diffusion of oxygen if the partial pressure is dropping in the atmospheric air?
the rate of diffusion would decrease
What are the two methods that oxygen is carried in the blood?
dissolved oxygen follows Henry’s law such that the amount dissolved is proportional to its partial pressure
the second method is through the blood bound to hemoglobins on RBC
How many oxygen molecules can bind to one hemoglobin molecule?
4
What happens when 1 oxygen molecule binds to hemoglobin?
it alters the structure of hemoglobin to make it easier for other oxygen molecules to bind
What is SaO2?
oxygen saturation
What is O2 capacity? Can SaO2 be near maximum but still have inadequate oxygen delivery? Explain.
97.5%. Yes because there is no guarantee that the blood is well-oxygenated.
What is a normal blood concentration for Hb?
75%
What is a normal O2 capacity?
95-100%
How does the Q for the pulmonary circulation compare to the systemic circulation?
the volume of blood passing through the lungs per minute
systemic is the whole body so Q is much larger
What is VO2? What variables do we use to measure it?
oxygen consumption,Qx arterial O2 - Venous oxygen
What methods can gases be transported through the blood?
dissolved, as bicarbonate and, combined with proteins as a carbonic compound
How much oxygen can be dissolved in the blood?
20.1mL
Does the amount of oxygen dissolved in the blood meet the metabolic demands of the body?
through oxidative phosphorylation in mitochondria. this generates ATP. Without ATP there is a loss of resting membrane potential and loss to maintain cardiac functions
What are the functions of the urinary system?
to eliminate metabolic wastes and homeostatic ally regulate the water and electrolytes composition of the body fluids
What is urea? What are some situations where you might have an excess of urea in the blood?
a byproduct of amino acid catabolism. Kidney disfunction
What systems of the body are involved in waste removal?
Kidneys, ureters, urinary bladder, and urthra
How much of resting cardiac output supplies the kidney?
20-25%
Why do we have such high blood flow to one organ?
because the kidneys filter the blood
What are the differences between the glomerular capillaries and other systemic capillaries?
It is highly regulated
What is oncotic pressure? What is its effect on glomerular filtration?
pulling pressure. It increases it
What does GFR mean?
glomerular filtration rate
What is a normal GFR?
125mL/min
How much of GFR is reabsorbed?
99%
What is autoregulation?
the ability of the nephrons to adjust their own blood and FFR without external control
What is the effect of sympathetic stimulation of filtration?
constriction of the afferent arteriole would decrease GFR and urine production
Where is renin produced? What is its action?
the kidney causes vasoconstriction and water conservation, including decreasing filtration stimulating aldosterone secretion, and increasing water and electrolyte reabsorption.
Where is angiotensin converting enzyme produced?
the liver
What are the effects of angiotensin II on blood pressure and blood volume?
blocks high blood pressure
Which section of the nephron is the primary site of reabsorption?
proximal convolution tubule
What would be the effect of inadequate ATP on removal of sodium from the filtrate?
there would be no energy for reabsorption
What provides the energy for most reabsorption?
active transport
What % of filtrate is reabsorbed in the PCT?
85%
What is absorbed in the descending loop of Henle?
water and sodium chloride
What is absorbed in the ascending loop of Henle?
sodium chloride
How does the osmolarity of the filtrate compare between the PCT and the loop of Henle?
the loop of henle increasing the filtrate
What substances are secreted into the nephron?
urea, ureic acid ammonia, catecholamines, prostaglandins, pollutants, drugs
How are substances transported into the nephron, actively or passively?
actively
What substances are secreted into the nephron to regulate acid-base balance?
H and HCO3
Where is aldosterone secreted from?
adrenal cortex
What stimulates aldosterone secretion? Does aldosterone directly increase water reabsorption?
decreased sodium I the blood, decreased blood pressure and angiotensin production. Yes it does
Where is ADH secreted from?
posterior lobe the pituitary gland due to increased blood osmolarity and dehydration
What are the actions of ADH on the nephron? What type of channels are made in response to ADH?
makes the duct more permeable to water and allows filtrate to diffuse. Makes aquaporins
What would be the effect of increased urine volume on blood volume?
blood volume would decrease
What is the role of the nephron in water retention?
allows smalls molecules and wastes like water pass through
What is the countercurrent multiplier?
the salinity gradient in the medulla
What is the difference in osmolarity between the cortex and the medulla, and what role does this play in water retention?
lower in the medulla than the cortex. This makes the medulla more permeable to water
What would happen to the retention of water with a low osmolarity in the filtrate?
the water retention would increase
