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BIO 102 > quiz 7 > Flashcards

quiz 7 Flashcards

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Biology 101 flashcards
1
Q

complex functions of single-celled organisms

A
  • locomotion
  • feeding
  • decision making
  • sensing (i.e. harpoons that detect nearby organisms and stab them)
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2
Q

common problems with the physiology of multicellular organisms (that are not problems for unicellular organisms)

A
  • gas exchange
  • nutrient/waste delivery
  • water balance
  • central control processing (internal homeostatic, motor control, external sensory stimuli)
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3
Q

materials needed to diffuse in/out of cells

A
  • oxygen in
  • CO2 out
  • nutrients in
  • waste out

*easy to diffuse with single cells, challenging with layers

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4
Q

rate of diffusion

A

about 100 micrometers every 2.5 seconds

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5
Q

diffusion in water vs air

A
  • diffusion much slower in water/fluid

- explains why pneumonia or covid causes trouble getting enough oxygen, fluid in alveoli

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6
Q

how does diffusion impact metabolic rate

A
  • metabolic rate can be stressed by a greater diffusion distance, as diffusion takes time (materials take longer to enter/exit cells)
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7
Q

basal and functional metabolic rates

A
  • basal metabolic rate is consistent among organisms, both unicellular and multicellular
  • functional metabolic rate changes depending on movement
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8
Q

how do capillaries solve diffusion problems

A
  • diffusion works fine when cells are close to capillaries, but cells further back struggle with nutrition and waste (flux of materials)
  • more capillaries = shorter diffusion distances, increasing plumbing is a solution
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9
Q

mouse capillary experiment

A
  • mice put in low oxygen and grew more capillaries in thin ear tissue
  • increasing amount of blood vessels allowed greater oxygen delivery to cells

***another possible solution to low O2 environment: increase amount of hemoglobin (protein that carries it)

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10
Q

connectivity of systems for metabolism

A
  • multicellular organisms have a gas exchange surface (respiratory system) and a mechanism for delivering gas in/out of the system (cardiovascular system)

Highly connected!

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11
Q

diversity of respiratory surfaces

A
  • we can use words like “more derived” or “less derived”, no system is better

examples

  • transdermal: diffusion through skin
  • spiracles on grasshoppers squeeze air in and out
  • gills highly efficient at extracting oxygen from water (very little oxygen in water)
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12
Q

respiratory anatomy of mammals

A

large conducting airways
-cartilage (strong, prevents collapse), cilia (moves detritus up and cleans), smooth muscle

small airways (alveoli)
 - some smooth muscle (can cause asthma problems if too tight), no cartilage/cilia because gas exchange (needs to be thin)
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13
Q

how does airway diameter impact airflow?

A
  • airway becomes narrower when smooth muscle contracts, asthma can cause this
  • albuterol is smooth muscle relaxer
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14
Q

how does gas exchange work in the alveoli?

A
  • capillary wall is one cell thick

- materials diffuse in and out at the same time, O2 going to blood and CO2 leaving blood move independently

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15
Q

CF complications with cilia

A
  • cilia don’t function properly in people with CF, so the lungs can’t be cleaned out
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16
Q

what factors impact ability to oxygenate blood?

A
  • amount of air moved in/out of lung
  • size of conducting airways (asthma can shrink)
  • number of alveoli (emphysema from smoking can decrease)
  • number of functioning alveoli (pneumonia and illnesses cause non-functioning alveoli with fluid)
  • alveoli blood flow (clots)
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17
Q

importance of lung surface area

A
  • lung SA is huge which allows for fluctuations in our metabolic rate (more oxygen needed)
  • tissue consumes 5L of oxygen per minute when exercising
  • as SA increases moving down the lung (branching), velocity of oxygen decreases
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18
Q

what is partial pressure

A
  • partial pressure = % gas in atmosphere x barometric pressure
  • includes both a concentration component (oxygen is 21% of gas in atmosphere) and a pressure component (weight of atmosphere)
19
Q

how does gas equilibration work?

A
  • directional movement of gas based on partial pressure, not concentration!!
  • takes 0.25 seconds to equilibrate in alveoli, so lungs are rarely limiting factor in ability to oxygenate
20
Q

how does partial pressure change across locations?

A

% oxygen in atmosphere stays the same but barometric pressure changes, so partial pressure changes

21
Q

oxygen cascade in the respiratory system

A

oxygen levels decrease as you approach the “end user” of the cell

ambient air - alveolar gas - arterial blood - capillaries - mitochondria

22
Q

partial pressures of oxygen in air and within the body

A
  • ambient air: 150-160 mmHg
  • alveoli/arterial: 100 mmHg
  • venous: 40 mmHg
23
Q

partial pressures of carbon dioxide in atmosphere and in body

A
  • ambient air: ~0.3 mmHg
  • alveoli/arterial: 40 mmHg
  • venous: 46 mmHg
24
Q

why won’t alveolar gas levels match the ambient air?

A
  • alveoli are mixing chambers; we never fully expel the air

- impossible to reach PO2 as high as in the atmosphere with this left over air

25
Q

how do muscles aid in ventilation?

A

inspiration is an active process

  • diaphragm is a dome that flattens when contracted, generating a suction pressure
  • external intercostals between ribs help

expiration is a passive process
- muscles relax

26
Q

impact of high altitude on partial pressure of oxygen

A
  • Mt Everest partial pressure at 40 mmHg, equal to venous partial pressure
  • most people can’t survive extreme high altitude
  • people will act drunk, be unable to do simple tasks, and take risks
27
Q

impact of low altitude on partial pressure of nitrogen

A
  • symptoms of high nitrogen levels can begin at 70 ft underwater (triple the ambient pressure of sea level)
  • Nitrogen narcosis also called “rapture of the deep”
  • solution: lower nitrogen content in gas tank (helium is replacement)
28
Q

danger of fast pressure changes while diving

A
  • as pressure decreases, nitrogen leaves tissues and forms bubbles
  • can bubble in joints causing “the bends” or bubble in a blood vessel which can block flow and cause death
  • to avoid this, divers must slowly ascend to lower pressure–like bubbling on a soda can, the pressure must change gradually
29
Q

how do oxygen-binding proteins aid in delivery to tissues?

A
  • oxygen not very soluble in water, binding pigments increase delivery
  • most iron or copper based
    * hemoglobin is iron-based, carries 4 O2, found in red blood cells
    * hemocyanin is copper-based, carries 1 O2, found in plasma
30
Q

importance of myoglobin in animals

A
  • oxygen-binding protein found in muscle

- oxygen transferred from hemoglobin to form reserves in highly metabolic tissue (like neurons)

31
Q

hemoglobin subunits and oxygen binding

A
  • hemoglobin has 4 subunits; 2 alpha chains and 2 beta chains
  • first 2 added easily even with lower PO2 (steep curve with high affinity)
  • last 2 added less easily and require higher PO2 (flatter curve with lower affinity)
  • full oxygen saturation at 60 PO2, even though alveoli PO2 is normally 100
32
Q

what does the shape of graph of hemoglobin saturation for PO2 levels indicate?

A
  • sigmoid shape indicates that there’s cooperativity between multiple subunits of hemoglobin
  • affinity very high for first 2 oxygens, then lowers for last 2
33
Q

affinity

A

oxygen saturation per change in PO2

34
Q

shape of myoglobin saturation graph for PO2 levels

A
  • myoglobin found in muscles, oxygen transferred from hemoglobin
  • not sigmoid (single polypeptide chain)
  • left shifted curve indicates higher affinity for oxygen than hemoglobin
35
Q

why does myoglobin have a higher oxygen affinity than hemoglobin?

A
  • in muscles; must receive oxygen from hemoglobin (must bind at PO2 that hemoglobin releases)
  • only one polypeptide; easier to saturate with no sigmoid curve
36
Q

roles of hemoglobin and myoglobin

A
  • hemoglobin delivers oxygen

- myoglobin is a depot for oxygen, allowing for rapid changes in metabolism

37
Q

hematocrit and its percentages in people

A

hematocrit: % whole blood packed with RBCs
- 42-45% in women
- 45-48% in men
- endurance training increases 2-3%, body needs to produce more RBCs to sustain exercise

38
Q

where and why are RBCs formed?

A
  • to increase oxygen delivery, body must increase RBC number

- RBCs formed in bone marrow, surrounded by lots of fat

39
Q

what signals synthesis of more RBCs?

A

Erythropoietin (EPO) released from kidneys when tissues are hypoxic (caused by various kinds of anemia)

40
Q

results of PulseOx experiment

A
  • infrared light in PulseOx measures arterial O2 levels

- Megan had high air hunger but barely any O2 change

41
Q

results of breath holding experiments in divers

A
  • oxygen saturation will remain normal over 2 minutes into breath holding
  • although normal alveoli PO2 is 100 mmHg, hemoglobin will remain saturated until PO2 is at 60 mmHg
  • blood can remain fully saturated even with decreasing partial pressures of oxygen!
42
Q

at what point does low oxygen affect breathing?

A
  • ventilation rates increase when PO2 gets to 60 mmHg (hemoglobin not fully saturated)
  • this requites high elevation (breathing shouldn’t be impacted until at least 10,000 feet)

*oxygen is not the main driver of breathing!

43
Q

how does our body sense oxygen levels?

A
  • peripheral chemoreceptors: aortic and carotid bodies

- humans mainly use carotid bodies, located at bifurcation of carotid arteries

44
Q

what is the main determinant of breathing rate? why?

A

carbon dioxide–ventilation rates will increase with very small PCO2 increases; most people can only tolerate 9% CO2 inspired

  • CO2 forms carbonic acid with water
  • enzymes that drive our body’s reactions have a narrow pH range, causing “air hunger” when carbonic acid levels are higher

BIO 102 (14 decks)

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