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44 Cards in this Set

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In vertebrates, exchange of substances between the blood and the interstitial fluids occurs in the ___________.
- capillaries
In the cardiac cycle, when is the blood pressure at its maximum?
- when the ventricles are contracting during systole.
systole and diastole describe what in mammals?
- systole = contraction
- diastole = relaxation
of the ventricles in mammals
What does a blood pressure of 140/100 mean?
- pressure during ventricular contraction is 140
- pressure during ventricular contraction is 100
what are the most abundant cells in the blood?
- erythrocytes
what don't the mature RBCs of human not contain?
- contain no nuclei or endoplasmic reticulum.
How do the RBCs and WBCs differ in quantity?
- There are at least 500 times as many red as white blood cells.
where are RBCs generated? where are old RBCs removed?
- in the bone marrow
- removed in the spleen
what is the function of leukocytes?
- to destroy foreign cells or produce antibodies
Lifetime of an individual RBC
120 days (4 months)
Where is blood at its lowest pressure?
- the capillaries
Is the blood pressure greater or lesser than the osmotic pressure at the arterial end of the capillary bed?
- BP is greater than osmotic pressure
What process occurs at the arterial end of the capillary bed?
- filtration
What happens to the blood pressure and the osmotic potential as the blood enters the capillaries from the arterioles?
- BP decreases
- Osmotic potential increases
The diameter of the capillary is about the same as what?
- a RBC
Which blood vessels have the greatest total cross-sectional area?
- the capillaries
How does histamine cause inflammation?
- makes blood vessels expand
- increases the pressure in the capillaries
Are walls in the veins or the arteries more expandable?
- walls of the veins are more expandable
what causes heart murmurs?
- sounds produced by defective heart valves
What causes varicose veins?
- when valves within veins can no longer prevent backflow of blood
What mechanisms facilitate the return of venous blood to the heart
- gravity, when veins are above the heart
- contraction of skeletal muscles
- breathing
- valves in veins
what do precapillary sphincters do?
- shut off the supply of blood to the capillary bed
How does myoglobin benefit muscle cells?
- releases bound O2 at lower PO2 conditions than hemoglobin does.
What is internal ventilation of the gas exchange surfaces dependent on?
- blood flow
In the lung, there is a concentration gradient of CO2 from the erythrocyte to the ___________,
and a concentration gradient of HCO3- from the plasma to the ________.
- CO2 from the erythrocyte to the lung
- HCO3- from the plasma to the erythrocyte
carbonic anhydrase catalyzes a reaction between what?
CO2 and water (to form H2CO3)
What membrane covers the abdominal organs of the vertebrate gut?
peritoneum
What layer is the location of the blood and the lymph vessels in the small intestine that carry away absorbed nutrients?
submucosa
What activates the inactive form of stomach enzymes?
low pH
How does bile aid in the breakdown of lipids?
by emulsifying the lipids
What neutralizes the acidic chyme in the small intestine?
bicarbonate from the pancreas
The major function of the colon (large intestine) is
reabsorption of water
What typically causes the release of gastrin? what inhibits release of gastrin?
causes release of gastrin = the presence of food in the stomach
inhibits release = low pH
The hormone secretin is a chemical message that triggers what?
pancreatic secretion
when is insulin released by the pancreas?
when blood levels of glucose rise
factors in the movement of water into tissues?
- osmotic gradient
- fluid pressure
- diffusion
- salinity gradient
ammonia and urea are waste products from the metabolic breakdown of what?
proteins
What drives the process of filtration from the capillaries into the glomerulus?
arterial blood pressure
What enters Bowman's capsule from the bloodstream during filtration?
- water
- glucose
- ions
- amino acids
what part of the nephron functions as a counter current multiplier system?
-loop of henle
What % of fluid that is filtered into Bowman's capsule is reabsorbed into the blood within the kidney?
more than 95%
What part of the nephron reabsorbs valuable molecules such as glucose, amino acids, and vitamins?
proximal convoluted tubule
The kidneys help regulate the acid-base balance by controlling the level of what in the blood?
H+ and HCO3-
What is the effect of ADH (antidiuretic hormone)?
- increases absorption of water
- increases blood volume
- increases urine concentration