Lab Exam Flashcards
What regulates the concentration of sugars (glucose) in the blood?
the antagonistic controls of insulin and glucagon
Which peptide hormone is released when glucose levels are high?
insulin
What releases insulin into the bloodstream?
the pancreas
What peptide hormone is released when glucose levels are low?
glucagon
What releases glucagon into the bloodstream?
the pancreas
what is the novel technique used in the Bo et al., (2013), study?
a technique that detects glucose concentrations using a DNAzyme (a synthetic enzyme)
What is DNAzyme?
a synthetic enzyme that detects glucose
made of a G-rich oligonucleotide and hemin
acts like a peroxidase in the presence of glucose oxidase and glucose to oxidase ADHP into resorufin
What is DNAzyme made of?
a G-rich oligonucleotide and hemin
What is the function of DNAzyme?
to oxidize ADHP into resorufin in the presence of glucose oxidase and glucose
acts like a peroxidase
What enzyme does DNAzyme imitate?
peroxidase
What is ADHP?
10-acetyl-3,7-dihydroxyphenoazine
What colour is ADHP before it’s oxidized?
colourless
What colour is ADHP when it’s oxidized?
red
How is the concentration of glucose determined?
spectrophotometry at 570 nm used to detect resorufin which a standard curve can be made from to determine glucose concentration in the sample
Who won the Nobel Prize in 1923? For what?
Frederick Banting won for discovery of insulin
What type of feedback loop is regulation of blood glucose?
negative feedback
explain how blood glucose levels are regulated by a negative feedback loop
when blood glucose is high:
- B cells of pancreas are stimulated to secrete insulin into the bloodstream
- insulin targets organs to increase their glucose uptake
= reduces glucose levels in blood (brings parameter back to set point)
AND
- a cells of pancreas are inhibited to prevent the secretion of glucagon into the bloodstream
= reduces glucose levels in blood (brings parameter back to set point)
Which pancreatic cells secrete insulin?
beta cells
Which pancreatic cells produce glucagon?
alpha cells
Where are the pancreatic cells which secrete insulin and glucagon located?
in the Islets of Langerhans of the pancreas
Describe how blood glucose levels are antagonistically controlled
insulin is secreted by pancreatic B cells to lower glucose levels
glucagon is secreted by pancreatic a cells to raise glucose levels
What was the purpose of the glucose metabolism experiment?
- to observe the behavioural differences (gill cover, movement) between control fish and fish exposed to insulin
- to use a DNAzyme to detect the concentration of glucose in the fish’s urine and blood samples when exposed to glucose or insulin, or neither (control)
What organism was used in the glucose metabolism experiment?
diamond tetras, Moenkhausia pittieri
What were the 3 parts of the glucose metabolism experiment?
A (lab coordinator): prepare hemin-G-quadruplexes DNAzymes solution
B: Observe fish behaviour (control v. insulin)
C: Measure glucose from tank water and blood samples (control v. glucose exposed v. insulin exposed)
What was the hemin-G-quadruplexes DNAzyme solution prepared?
- a purified G-rich oligonucleotide was mixed with a hemin solution (hemin, Tris-HAC pH 8, NaCl, Triton X-100)
- probe solution: ADHP + glucose oxidase (GOx) combined (ADHP + GOx + Tris-HAC pH 8, Triton X-100)
- oligonucleotide/hemin solution mixed with probe solution
How much insulin was the experimental fish exposed to to observe behaviour the glucose metabolism experiment?
0.5 IU/mL insulin in 200 mL of aquarium water at 25 C
What were the control conditions for the the glucose metabolism experiment?
200 mL of aquarium water at 25C
no additions
How were the data collected for behaviour observations in the glucose metabolism experiment?
for a period of 15s, a student counted the number of times the gill covers open and closed and another student counted the distance (cm) the fish moved, repeated this for 5 minutes
repeated the 15s interval counting for 5 minutes at 30, 60, 90, 120 minutes
at every half hour interval, samples of the aquarium water were taken
repeated for insulin-exposed fish
How were data collected for Part C (measuring glucose concentrations) in the glucose metabolism experiment?
spectrophotometry at 570 nm max absorption
How were the blood samples collected for the glucose metabolism experiment? How many were there per group?
12 blood samples were collected from the caudal vein of 3-5 fish and pooled and diluted by 100x
these fish included control, glucose exposed, and insulin exposed
How much glucose was the treatment fish orally administered for the blood samples in Part C of the glucose metabolism experiment?
1.67 mg glucose/g body weight
How much insulin was the treatment fish injected with for the blood samples in Part C of the glucose metabolism experiment?
0.01 IU/g body weight
How were the blood sample solutions prepared for spectrophotometry in the glucose metabolism experiment?
the 12 blood samples were combined with 1 mL of probe solution (ADHP + GOx + oligonucleotide/hemin)
What samples were used in the spectrophotometry part of the glucose metabolism experiment?
12 previously collected blood samples from control fish, glucose fish (1.67 mg glucose/g body weight), and insulin fish (0.01 IU/g body weight) + probe solution
and
the 8 aquarium tank water samples taken every half hour in Part B (contain urine with glucose levels) + probe solution
1 mL probe solution per sample = ADHP + GOx + oligo/hemin
10 uL tank water or blood per sample
How were the urine samples (tank water samples) and blood samples prepared for spectrophotometry?
10 uL of each blood and urine sample were combined separately with 1 mL of probe solution and incubated for 45 minutes
Why was urine and blood samples used in the spectrophotometry for the glucose metabolism experiment?
glucose levels in urine are a good indicator for the amount of glucose in the bloodstream (high in urine = high in blood)
blood is a direct indicator for how much glucose is in the bloodstream
What maximum absorbance was the spectrophotometer set to for the glucose metabolism experiment?
570 nm
What was the blank solution used for the spectrophotometry in the the glucose metabolism experiment?
the probe solution (ADHP + GOx + hemin/oligo)
Why was a standard curved used for the assessment of glucose concentrations in the samples for the the glucose metabolism experiment?
a standard curve shows a linear relationship between a concentration of an unknown solution in a sample and its corresponding absorbances at 570nm
the equation of the line can be used to determine the glucose concentration for each sample
What must be considered when determining the glucose concentrations from the standard curve for the the glucose metabolism experiment?
the dilutions made before blood samples were mixed with probe solution (100x)
What trends were observed in the urine-glucose experiment for the glucose metabolism experiment?
glucose concentration in urine per gram of fish was higher in the insulin-exposed fish than in the control
unexpected - additional insulin should lower urine-glucose until glucagon production can catch up
reasons?
- maybe not enough time for glucose to metabolize?
- maybe too much time and glucagon caught up and produced more glucose?
- type of insulin used?
- dose?
- location of injection?
- timing and content of last meal?
What trends were observed in the blood-glucose experiment for the glucose metabolism experiment?
blood from fish exposed to glucose had highest glucose concentrations
blood from fish exposed to insulin had lowest glucose concentrations
blood from control fish had middle ground glucose concentration
expected results: additional glucose should raise blood-glucose until insulin production can catch up; additional insulin should lower blood-glucose until glucagon can catch up; in the control, glucagon and insulin secretion should be balanced
What trends were observed in the gill cover movement experiment for the glucose metabolism experiment?
insulin-exposed fish had higher rate of gill cover movement than control
explanation: possibly because an increased insulin content will increase the rate of glucose metabolism = increase the demand for O2 = respiration occurs over the gills in fish so more movement required to pass more oxygenated water across gills
What is spectrophotometry?
a technique used to quantitatively measure energy (usually light) absorbance by a specific molecule in a solution
can be used to determine a molecule’s concentration in a solution
What is the maximum absorption?
the wavelength (nm) that light is being maximally absorbed by the specific molecule in the solution
What is the relationship between absorbance and the concentration of the molecule in the solution?
they are proportional to each other
and they are proportional to the length of the light path
What is Beer’s Law (or Beer-Lambert Law)?
Absorbance of a molecule is proportional to its concentration in the sample and to the length of the light path
A = kLC
A = absorbance (no units)
k = coefficient of wavelength-dependent molar absorptivity (1/M*cm)
L = length of light path (cm)
C = concentration of absorbing molecule (M)
Why does absorbance have no units?
it’s a ratio of the intensity of the light hitting the absorbing molecule to the amount of light that’s passing through the absorbing molecule
all the units cancel each other out in A = kLC
What is Intensity (I) in spectrophotometry?
the amount of electromagnetic radiation occurring on a solution
ie., the energy of radiation per unit area per unit time
is this the amount of light hitting the solution?
What is transmittance in spectrophotometry?
the %T is the amount of light that hits a solution that actually passes through the solution
What does it mean for a solution to have %T = 100?
the solution is completely transparent and 100% transmittance is occurring
ie., 100% of the light hitting the solution is also passing through the solution
What is the equation for %T?
%T = 100(It / I0)
where
%T = transmittance
It = light transmitted through the sample
I0 = light hitting the sample
What is wavelength in spectrophotometry? what is it based on? how is it often represented?
represented symbolically by lambda
the frequency at which a molecule is absorbing electromagnetic radiation
based on %T
represented logarithmically because of the massive range of values
How is the absorbance of a sample represented (what is the formula)?
A = log(100 / %T)
or
A = 2.000 - log (%T)
2.000 because log(base10) * 100 = 2
What will the absorbance of a transparent sample be?
when %T = 100, A = 0
A = log(100/100) = 0
What will the absorbance of a sample be when %T = 10?
When %T = 10, A = 1
A = log(100/10) = 1
What will the absorbance of a sample be when %T = 1?
A = log(100/1) = 2
What will the absorbance of a sample be when %T = 0.1? %T = 0.01?
A = log(100/0.1) = 3
A = log(100/0.01) = 4
Describe a standard curve in spectrophotometry
absorbances for the standards are plotted as a function of their concentrations
it assumes linear relationship between concentration and absorbance
uses a control that contains all the reagents except the unknown
What is the control in spectrophotometry? what was it in the glucose metabolism experiment?
the blank solution - contains all reagents except for the one with unknown concentration
in the experiment, it was the probe solution (ADHP + GOx + oligo/hemin)
How is the blank used to determine the maximum absorbance?
set the spectrophotometer to 0 and insert the blank, measure the max absorption wavelength and use this to measure the wavelengths for the samples
How can the equation of the line produced by the standard curve be used to determine concentrations of glucose?
the absorbances of each sample are plotted against the concentrations and the slope is used to calculate the unknown concentration
x = kL
where
k = y/x (slope)
y = absorbance
x = unknown concentration
What 4 animal types were used in the comparative anatomy lab?
fish
adult frog (amphibian)
bird (reptile)
mouse (mammal)
What is positive pressure breathing?
when the pressure inside the lungs is greater than the pressure in the atmosphere
what is negative pressure breathing?
when the pressure inside the lungs is lower than the pressure in the atmosphere
What type of integuments do each of the 4 animal types have?
fish: skin + scales
frogs: skin
birds: skin + feathers
mouse: skin + hair (fur)
Are mucous cells present in each of the 4 animal types?
fish: yes
frogs: yes
birds: no
mouse: no
Is thermoregulation exhibited in each of the 4 animal types?
fish: no, ectotherm
frog: no, ectotherm
bird: yes, endotherm
mouse: yes, endotherm
What appendages do each of the 4 animal types?
fish: paired and unpaired fins
frogs: tetrapod, paired fore and paired hind limbs
birds: paired wings, paired hind limbs
mouse: tetrapod, paired fore and paired hind limbs
How many circulatory circuits do each of the 4 animal types have?
fish: 1
frog: 2
bird: 2
mouse: 2
How many heart chambers do each of the 4 animal types have?
fish: 2
frog: 3
bird: 4
mouse: 4
What are the respiratory organ(s) used in each of the 4 animal types?
fish: gills
frog: skin + lungs
bird: lungs
mouse: lungs
Are air sacs or alveoli present in each of the 4 animal types?
fish: no (no lungs)
frog: yes
bird: yes
mouse: yes
What are the gas exchange surfaces in each of the 4 animal types?
fish: lamellae of gill filaments
frog: skin + alveoli in lungs
bird: parabronchi in lungs
mouse: alveoli in lungs
Are the air sacs or alveoli directly involved in gas exchange in each of the 4 animal types?
frog: NA (no air sacs or alveoli, no lungs)
fish: yes
bird: no (parabronchi instead)
mouse: yes
What type of pressure breathing do each of the 4 animal types have?
fish: NA (no lungs)
frog: +
bird: +
mouse: -
How do the respiratory systems compare between fish and frogs given that they’re both aquatic?
fish:
- organ: gills
- gas exchange surfaces: lamellae of gill filaments
- dissolved O2 from water
- countercurrent, unidirectional flow of O2
frog:
- organ: skin + lungs
- gas exchange surfaces: skin + alveoli in lungs
- O2 from atmosphere
- tidal flow bidirectional through lungs
- non-directional flow over skin
fish do not have lungs, therefore do not have alveoli or any type of pressured breathing
frogs have lungs with alveoli for gas exchange and have + pressure breathing
How do the circulatory systems compare between fish and frogs given that they’re both aquatic?
both are closed systems with a chambered heart pumping blood through vessels
fish:
- 2 chambers (1 atrium + 1 ventricle)
- single circuit
frog:
- 3 chambers (2 atria + 1 ventricle)
- double circuit (pulmonary + systemic)
How do the digestive systems compare between fish and frog given they’re both aquatic?
How does the respiratory system compare between frog and mammals given they’re both tetrapods?
both have lungs with alveoli and have tidal bidirectional ventilation, but frogs can also respire across their skin
frogs:
- organ: skin + lungs
- GE surface: skin + alveoli in lungs
- both tidal bidirectional (lungs) and nondirectional (skin)
- ectotherm (metabolism lower = respiration lower?)
mammals:
- organ: lungs
- gas exchange surface: alveoli in lungs
- only tidal bidirectional ventilation
- endotherm - metabolism higher (respiration higher?)
How does the circulatory system compare between frog and mammals given they’re both tetrapods?
both have closed circulatory systems with a chambered heart to pump blood through vessels through TWO circuits
frog:
- 3 chambered heart (2 atria + 1 ventricle)
mammal:
- 4 chambered heart (2 atria + 2 ventricles)
How does the digestive system compare between frog and mammals given they’re both tetrapods?
How does the circulatory system compare between birds and mammals given that they’re both endotherms?
both have double circuit closed circulatory systems with a 4 chambered heart to pump blood through the vessels
- both have hepatic portal systems
birds:
- aortic arch arches to the right
mammals:
- aortic arch arches to the left
How does the respiratory system compare between birds and mammals given that they’re both endotherms?
Both have lungs as their respiratory organ
birds:
- GE surfaces: parabronchi in lungs (alveoli not involved in GE)
- crosscurrent unidirectional ventilation (2 exhale, 2 inhale)
- highly efficient at GE
- continuous
mammals:
- GE surfaces: alveoli in lungs
- tidal bidirectional ventilation
How does the digestive system compare between birds and mammals given that they’re both endotherms?
Are the differences in the systems between birds and mammals a result of demands for flight or endothermy?
birds ventilate crosscurrently and unidirectionally to maximize the efficiency of gas exchange required by the demands of flight
not endothermy related otherwise mammals may have evolved this too
the 4 chambered heart may be related to demands of endothermy as frogs and fish have less chambers
What are the major external anatomical features of a fish?
external nares (olfactory only = no respiration)
no moveable eyelids
mouth
paired fins:
- pectoral (usually anterior)
- pelvic (usually posterior, but can be anywhere in more evolved fish)
unpaired fins:
- dorsal fins: along dorsal midline, can be single, double, triple, or one long fin from head to caudal fin
- anal fin: single or double, mid-ventral and posterior to anus, stabilizing
- caudal fin: extends from trunk, shape depends on swim type
- adipose fin: posterior to dorsal fin, small, soft
What are the circulatory system features of a fish?
2 chambers
located in the pericardial cavity
conducts single circuit system = blood pass through heart one time and then to gills
blood at gills is oxygenated and circulates through body to deoxygenate
deoxygenated blood enters and leaves heart
heart pumps deoxygenated blood out to the gills to be oxygenated
Why would a fish only need a single circulatory system compared to frogs, birds and mammals?
fish have a low metabolic rate = don’t require quick distribution of oxygenated blood to cells
What are the respiratory system features of a fish?
gill covers (operculum) protect the respiratory organs and GE surfaces for a fish to control the flow of water over the gills
holobranch: an individual gill + the bony gill arch and the gill filaments (respiratory surface)
RESP SURFACE: gill filaments (lamellae of gill filaments)
What is a holobranch?
the respiratory structure in fish which includes an individual gill which is composed of a bony gill arch and its gill filaments
What are the digestive system features of a fish?
pharynx (where gills are) > opens directly into stomach
stomach is where initial digestion occurs > intestine
intestine is narrow and straight = where nutrient absorption and feces formation occurs
- surrounded by mesentery
intestine leads to anus where fecal waste is excreted
liver: processes and stores nutrients before entering circulatory system and produces bile to digest fats
gallbladder: stores bile
spleen: produces new cells and destroys old ones, sends components of old ones to liver via bloodstream for recycling
T or F: the spleen is a digestive organ
false
What are the digestive system features of a frog?
liver
gallbladder
stomach (large and saccular)
pancreas
cloaca
urinary bladder
What are the respiratory system features of a frog?
cutaneous respiration via skin
pulmonary respiration via lungs (+ pressure breathing)
alveoli in lungs (tidal bidirectional)
mucous glands on skin keep skin moist for enhanced GE (nondirectional)
also a bit in the mouth: buccopharyngeal respiration
What are the circulatory system features of a frog?
3 chambered heart (2 atria, 1 ventricle)
double circuit
Which frog species was used in the anatomy lab?
bullfrog, Lithobates catesbeiana
Describe the integument of frogs
thin, vascular skin that is highly glandular with mucous cells = cutaneous gas exchange surface
What are the reproductive system features of a frog?
testes or ovaries
kidneys x 2
What are the circulatory system features of a bird?
4 chambered heart
double circuit
aortic arch to the right
extremely efficient at pumping blood
What arteries are found in birds?
brachiocephalic
common carotid
subclavian
pectoral
axillary
What veins are found in birds?
hepatic portal system + portal vein system include:
jugular
subclavian
axillary
brachial
hepatic portal
hepatic
What are the advantages of having 2 blood circuits for bird?
the pulmonary circuit can send blood to capillaries in the lungs for gas exchange
while the systemic circuit can send oxygenated blood to the cells of the body
What are the differences between arteries and veins?
arteries:
- move blood Away from the heart
- smaller cavity diameter for blood to travel = higher BP leaving heart
veins:
- bring blood back to the heart
- larger cavity diameter for blood to travel = lower blood pressure entering heart
What is the advantage of crosscurrent ventilation in birds?
GE occurs at capillaries in lungs via the parabronchi and is unidirectional
this allows for 2 inhales and 2 exhales = extremely efficient at gas exchange and meeting the high metabolic demands for flight
air also ventilates crosscurrently = air through the respiratory tract crosses the blood vessels for maximized contact and GE
What are the two major components of the bird stomach?
proventriculus
ventriculus
What is the proventriculus?
the anterior-most part of the stomach
it’s glandular (large glands fill submucosa) and lined with folds (plicae) and depressions (sulci)
What is the ventriculus?
aka the gizzard
follows the proventriculus
What is the site for digestion in birds?
the proventriculus
What cells make up the epithelial lining of the avian stomach?
simple columnar and then cuboidal at the base
what is the function of the gizzard/ventriculus? why is it important?
it mechanically breaks down food because birds do not have teeth
it is the grinding plates that line the lumen and contract powerfully
what substance do the cells within the secretory units of the avian stomach release?
keratinoid - a thick, horny material
What is the crop in avian digestion? why is it important?
an enlargement of the esophagus for food storage, it is a muscular pouch
Why is the position of the ventriculus important?
because birds do not have teeth, food is swallowed whole, it needs to be mechanically broken down before reaching the intestines
Describe the integument of a mouse
body is covered in hair except for soles of feet, nose, and tail
tail is covered in scales
gait = digitigrade
fore foot = 4 clawed digits
hind foot = 5 clawed digits
What type of gait do mice have? what does this mean?
digitigrade = walk on the toes, not the entire sole (ex. cats, dogs, rodents)
Describe the external features of a mouse head
vibrissae (whiskers) project outwards from the nose for tactile sensation
2 external nostrils on either side of the nose, naked patch of the nose between nostrils = rhinarium
philtrum = cleft of upper lip
1 0 0 3 dental for upper and lower jaws
flaps of skin extend between incisors and molars = gnawing
ridged palate
short neck connecting head to trunk
Describe the trunk of a mouse
thorax and abdomen sections
2 rows of 6 mammary gland nipples
anus at the base of tail
females: urethral and genital openings anterior to anus
males: large scrotal sacs may cover anus
Describe the circulatory features of a mouse
4 chambered heart
double circuit
pericardia has a parietal and visceral portion (visceral adhered to heart)
major blood vessels:
- superior vena cava
- pulmonary arteries
- pulmonary veins
- aorta
- aortic arch
What are the major blood vessels in a mouse?
superior vena cava
inferior vena cava
pulmonary arteries and pulmonary veins
aorta and aortic arch
What do the super vena cava and the inferior vena cava do in mice?
superior drains anterior body regions
inferior returns blood to heart from abdomen
both empty into the right atrium
What do the pulmonary arteries and veins do in mice?
pulmonary arteries carry blood away from the heart from the right ventricle to the lungs
the pulmonary veins return blood from the lungs to the left atrium
What does the aorta do in mice?
the aorta carries blood from the left ventricle to the body
What does the aortic arch do in mice? which way does it arch?
arches to the left
has 5 branches - 2 are the coronary arteries which supply the heart
What are the major valves in the mouse heart?
tricuspid (right)
bicuspid (left)
between the atria and ventricle
and semilunar between aorta and pulmonary artery
What are the features of the respiratory system of a mouse?
trachea and bronchi
lungs
- left (single) right (4 lobes)
the lungs are lined with the parietal pleura (wall of cavity)
and
the visceral pleura lines the actual lungs
the midline between them = mediastinal septum
How many lobes do lungs have in mice?
the left lung has one lobe
the right lung has 4 lobes
What are the 2 linings of mouse lungs?
the parietal pleura lines the cavity walls
the visceral pleura lines the lungs
the midline = mediastinal septum
Describe the trachea and the bronchi in mice
the trachea extends from the larynx to branch just before the lungs
the trachea divides into the bronchi which branch further until eventually the terminal bronchioles lead to the alveoli
What gland covers the anterior end of the mouse heart?
the thymus gland in young mice
What are the major components of the mammalian digestive tract?
membranous mesenteries
omenta
parietal peritoneum
diaphragm
liver
spleen
esophagus
stomach
duodenum
pancreas
jejunum
large intestine
caecum
What are the mesenteries?
fold of membrane that hold the stomach in place
What is the omenta?
part of the stomach that connects with the other abdominal organs (spleen)
What is the parietal peritoneum?
the lining fo the abdominal cavity
Where is the diaphragm?
separates the abdominal and thoracic cavities
Describe teh structure of the mammalian liver
5 lobes
T or F: all mammals have a gall bladder
false some do, some don’t
ex. rats don’t, mice do
Do mice have gall bladders?
yes
What does the spleen look like in mice?
red, flattened organ lying to the left and posterior of the stomach
Where is the esophagus in mice?
from the pharynx, through the thorax and into the cardiac portion of the stomach
Describe the stomach of mice
in the left side of the abdominal cavity below the liver
divided into anterior cardiac and posterior pyloric portion
What is the function of the pyloric part of the stomach in mice?
to control muscle movement of food from the pyloric portion into the stomach and small intestine
How do the duodenum, pancreas, jejunum, and ileum structurally interact in mice?
the pancreas has ducts that bend with the duodenum and the jejunum starts where the duodenum turns posteriorly
the ileum starts where the jejunum ends and the ileum runs into the caecum
Describe the large intestine of mice
composed of caecum, colon, rectum
What is the caecum?
the large, blind sac that is attached to the gut where the small and large intestines meet
What is the source of energy for all animals?
the chemical energy from ingested food
What is responsible for the synthesis of macromolecules in the body?
anabolic metabolism
What is responsible for the break down of macromolecules in the body?
catabolic metabolism
What do animal bodies do with the energy provided from metabolic processes?
the energy is used to drive energy-requiring processes like ion pumps, biosynthesis and to perform work like muscle movement and contraction
What is the metabolic rate of animals dependent on?
physiological and environmental conditions like body size, sex, activity, temperature, season, etc.
What was the purpose of the body size and metabolic rate experiment?
to examine how body mass affects metabolism in different animals
and to determine that while oxygen consumption is greater in larger animals, the rae of oxygen consumption per unit body weight is greater in smaller animals
How does body mass affect metabolic rate?
generally, smaller animals have higher metabolic rates per unit body mass
What did Max Rubner do?
in 1883, his results suggested that mammals have a constant relationship between size and metabolism which scales by a power of (weight)^2/3
What does Rubner’s ratio of body weight to metabolic rate assume?
the (weight)^2/3 ratio assumes that the pattern is due to differences in the ratio of SA to volume of an animal
How did Rubner explain his findings? What challenges this idea?
smaller mammals must have a higher metabolic rate due to maintaining a constant body temperature
poikilotherms (ectotherms) also follow this trend generally, so something other than body temperature must be causing it
What was Kleiber’s expression?
M = aW^b
a slightly more flexible expression for metabolism to body surface
where
M = total metabolism/time
a = normalization coefficient
W = body weight
b = scaling coefficient
What is the equation of straight line for Kleiber’s?
log M = log a + b (log W)
Where
log a = the y intercept
b = the slope
How is the value of a determined for Kleiber’s equation (the normalization coefficient)?
it can vary depending on the species and depends on M and W
What did Max Kleiber find was the most constant value for b (the scaling coefficient)? what does this mean?
0.75
body size and metabolism scale allometrically by a factor of 0.75
How does Kleiber’s idea challenge Rubner’s?
Rubner suggested it’s a scaling coefficient of 2/3 which can be explained by the differences in surface area to volume
Kleiber suggest it’s a scaling coefficient of 3/4 which cannot be as easily explained by SA to volume
What is one major reason why body weight is considered to be related to metabolic rate?
body weight influences the rate of oxygen intake and rate of oxygen consumption is a direct indication of metabolism
What methods are used to study metabolic rate?
direct and indirect calorimetry
Which method was used in our lab to measure metabolic rate?
indirect calorimetry
Describe indirect calorimetry
a method of measuring metabolic rate by examing oxygen consumption
Describe direct calorimetry and how the indirect method can be used in its place
direct calorimetry measures the heat produced when food is oxidized = represents the energy available to the animal
heat can be related to oxygen by stoichiometry
What unit is used for direct calorimetry? What is it?
Kcal = the amount of heat required to increase the temperature of 1 kg of water from 14.5-15.5 C
What is the respiratory quotient?
RQ = CO2 production / O2 consumption
What are the RQ value for carbohydrates? What is its caloric equivalent?
RQ = 1
5.05 Kcal / L O2 consumed
What are the RQ value for fats? What is its caloric equivalent?
0.7 RQ
4.69 Kcal/L O2 consumed
What are the RQ value for proteins? What is its caloric equivalent?
0.82 RQ
4.5 Kcal/L O2 consumed
What are the RQ value for a mix of carbs, fats, proteins? What is its caloric equivalent?
0.80 RQ
4.83 Kcal/L O2 consumed
What has the highest RQ?
carbohydrates
What organisms were used in the body size and metabolic rate experiment?
shore crabs (Hemigrapsus)
Bubble snails (Haminoea)
Sea cucumbers (Eupentacta)
marine blood worms (Glycera)
How was the electrode system calibrated for the body size and metabolic rate experiment?
calibrate dissolved O2 electrode system with Logger Pro 3:
2.Logger Pro 3 LabPro: 1 CH1 Dissolved Oxygen window, change units of measurement to % so it will measure the % dissolved O2 in the chamber
- add grains of sodium sulfite to chamber of seawater until voltage decreases to ~0.9-1.3V
- set loggerpro to 0% at stable voltage
- empty chamber and rinse with distilled water
- refill with air-saturated seawater (from tanks) and when reader reaches ~4V set to 100% dissolved O2
- set data collection for sampling rate of 4 samples per minute for half an hour
What equipment was used in the body size and metabolic rate experiment?
Qubit System dissolved Oxygen Monitor = measured rate of O2 consumption
Dissolved O2 electrode system with sea water in chamber and a magnetic stirrer with O2 electrode
screen placed between stirrer and animal
seawater filled to appropriate volume
water temperature is 10C
Why is sodium sulfite used to calibrate the seawater for the the body size and metabolic rate experiment?
it sequesters O2 from the water = sets the amount of dissolved O2 to 0% so that the voltage will be accurate
How were the data collected for the body size and metabolic rate experiment?
LoggerPro 3 was set to collect 4 samples per minute for half an hour
What was the procedure for the body size and metabolic rate experiment?
- turn off stirrer and add mesh screen and invertebrate
- make sure animal is covered comfortably by sea water and record volume; insert plunger and make sure there’s no air bubbles
- turn on stirrer and allow animal to ajdust for 5 minutes
- start collecting data on LoggerPro for half an hour or until 50% O2 saturation reached
- remove animal from chamber and weigh
- rinse chamber with seawater
repeat for another organism
What factors affect the solubility of O2? How do they affect solubility?
temperature = solubility decreases with increasing temperature
atmospheric pressure = increases with increasing atm pressure
salinity: decreases with increasing salinity
How was temperature corrected for in the body size and metabolic rate experiment?
solubility of O2 in distilled water equilibrated with air at the temperature of water to:
water temperature was 10C = 7.96 uL O2/mL at 1 atmosphere
How was atmospheric pressure corrected for in the body size and metabolic rate experiment?
by dividing the barometric pressure in the lab room by the atmospheric pressure (760 mmHg)
How was salinity corrected for in the body size and metabolic rate experiment?
salinity was measured in the saltwater samples as 30 ppt which has a correction factor = 0.73
What is the concentration of dissolved O2 for this example:
the %O2 at saturation at 0min = 99.9%
the %O2 at saturation at 15 min = 81.9%
temp = 10C
barometric pressure = 752 mmHg
salinity = 28 ppt
volume of seawater = 10mL ?
temp = 10C = 7.96 uL O2/mL water
pressure = 752/760 = 0.99
salinity = 0.75
concentration of dissolved O2 = 7.96 uL O2/mL water * 0.99 * 0.75
= 5.91 uL O2/mL water
What is the change in oxygen saturation for the animal over the 15 minute experiment in the example:
the %O2 at saturation at 0min = 99.9%
the %O2 at saturation at 15 min = 81.9%
temp = 10C
barometric pressure = 752 mmHg
salinity = 28 ppt
volume of seawater = 10mL ?
What was the change in O2 of the water?
99.9% - 81.9% = 18% for the animal
18% * 59.1 uL O2 = 10.6 uL O2 difference after 15 minutes = the amount of O2 the animal consumed in 15 minutes
What is the amount of O2 available to the animal for the example:
the %O2 at saturation at 0min = 99.9%
the %O2 at saturation at 15 min = 81.9%
temp = 10C
barometric pressure = 752 mmHg
salinity = 28 ppt
volume of seawater = 10mL ?
concentration of dissolved O2 = 5.91 uL O2/mL water
and there was 10 mL of seawater
5.91 uL O2/mL water * 10 mL water = 59.1 uL O2 available
What value represents the amount of O2 consumed by the animal in the example:
the %O2 at saturation at 0min = 99.9%
the %O2 at saturation at 15 min = 81.9%
temp = 10C
barometric pressure = 752 mmHg
salinity = 28 ppt
volume of seawater = 10mL ?
the change in O2 in the water chamber
change in animal * amount of O2 available to the animal
= 10.6 uL O2 consumed in 15 minutes
What is the rate of oxygen consumption / mg body weight / hour for the example:
the %O2 at saturation at 0min = 99.9%
the %O2 at saturation at 15 min = 81.9%
temp = 10C
barometric pressure = 752 mmHg
salinity = 28 ppt
volume of seawater = 10mL
weight = 100 mg?
animal consumed 10.6 uL O2 in 15 minutes x 60 min/1 hr = 42.6 uL O2/hour
42.6 uL O2/hr / 100 mg = 0.426 uL O2/mg/hr
How was the metabolic rate in Kcal/day calculated for the example:
the %O2 at saturation at 0min = 99.9%
the %O2 at saturation at 15 min = 81.9%
temp = 10C
barometric pressure = 752 mmHg
salinity = 28 ppt
volume of seawater = 10mL
weight = 100 mg?
O2 consumption L/day = (42.6 uL O2/hr * 24 hr) / 1,000,000 uL/L = 0.001 L O2/day
assume mixed diet (Kcal = 4.83 Kcal/L O2)
0.001 L O2/day * 4.83 Kcal/L O2 = 0.005 Kcal/day
How was the predicted metabolic rate (kcal/day) calculated for the example:
the %O2 at saturation at 0min = 99.9%
the %O2 at saturation at 15 min = 81.9%
temp = 10C
barometric pressure = 752 mmHg
salinity = 28 ppt
volume of seawater = 10mL
weight = 100 mg?
using Kleiber’s equation: M = aW^b
M = 70(0.001 kg) ^0.75 = 0.07 kcal/day
If a = 70 and the animal weighed 0.0001 kg, what would the predicted metabolic rate (kcal/day) according the Kleiber’s equation?
M = 70(0.0001 kg)^0.75 = 0.07 kcal/day
What is the qubit dissolved oxygen system?
a polarographic O2 electrode that monitors dissolved O2 concentration in water cuvettes
Explain how the qubit dissolved oxygen system works
dissolved O2 diffuses through a Teflon membrane and is reduced at the platinum electrode that directly touches the membrane
the platinum cathode is electrically connected to the silver-silver chloride anode via a KCl electrolyte
What is the electrochemical reaction at the platinum cathode of the qubit dissolved oxygen system?
O2 + 2H2O + 2 e- => H2O2 + 2 OH-
H2O2 + 2 e- => 2OH-
What is the electrochemical reaction at the silver-silver chloride anode of the qubit dissolved oxygen system?
4Ag => Ag+ + 4e-
4Ag+ + 4Cl- => 4AgCl
To what extent can the O2 electrode of the qubit dissolved oxygen system resolve a change of O2 in air-saturated water?
it can resolve a change of 0.1% O2 in air saturated water (100% O2)
How is the qubit dissolved oxygen system calibrated?
exposing the electrode to 0 O2 by
bubbling water with pure N2 or
add dithionite to the water in the sample chamber
What is the relationship between the voltage output of the O2 and the O2 concentration in the sample chamber of the qubit dissolved oxygen system?
the voltage output of the O2 electrode is linearly dependent on [O2] in the sample chamber
What are the 4 major sections of the neural and muscular physiology lab?
A: frog heart
B: muscle length and isometric tension
C: skeletal muscle contraction
D: isolated nerve function
describe the frog heart and how blood flows through it and the frog body
3 chambered: 2 atria, 1 ventricle
and a sinus venosus
venous blood from the venae cava collects in the sinus venosus and empties into the right atrium
pulmonary veins bring oxygenated blood to the left atrium
the atria contract to push blood into the ventricle which contracts to push blood out to the pulmonary and cutaneous arteries
T or F: the blood does not mix in a frog heart
false, blood from the 2 atria do mix in the ventricle
Where does blood from the 2 atria mix inside the frog heart?
in the ventricle
What sources do frogs have for their oxygen?
air and water
Explain the 2 circuit circulatory system of frogs
deoxygenated blood from the pulmocutaneous artery is sent to the lungs and skin for reoxygenation
oxygenated blood from the lungs enters the left atrium and oxygenated blood from the skin mixes with the deoxygenated systemic blood and returns to the right atrium
the blood moves through the ventricle and out through to the systemic and pulmocutaneous artery
What initiates contraction of the frog heart?
cardiac muscle cells (ie., it’s myogenic)
Which part of the frog heart is the fastest to initiate cardiomyocyte contraction?
sinus venosus
Which part of the frog heart is the slowest to initiate cardiomyocyte contraction?
the ventricle
Where does the heart beat originate from in the frog?
in the sinus venosus
What would happen if the sinus venosus was removed from a frog heart?
the atria would be initiating regular but slower contractions
How is a cardiac AP initiated in a frog heart?
depolarization of an adjacent cell activates the Na+ voltage-gated channels in the cardiomyocyte = depolarization of membrane
causes opening of K+ channels = repolarization
voltage-gated Ca2+ channels open and Ca2+ releases into sarcoplasm = muscle contraction
Ca2+ channels close
once repolarized, K+ channels will close
what controls the rate and force of heart muscles?
the PNS and SNS of the ANS
How does the SNS regulate heart rate?
an increased heart rate and force of contraction because of norepinephrine release = causes influx of Na+ and Ca2+ into cytoplasm
How does the PNS regulate heart rate?
decreased heart rate because of acetylcholine and opening of K+ channels and closes Ca2+ channels
