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Fall 2022 > Animal Physiology Exam 2 > Flashcards

Animal Physiology Exam 2 Flashcards

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1
Q

Hypothalamic-pituitary-gonadal axis (HPG)

A

responsible for regulation of the reproductive (sex hormones) and immune systems

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2
Q

The hypothalamus secretes what?

A

Gonadotropin releasing hormone (GnRH)

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3
Q

GnRH stimulates what?

A

Anterior pituitary to secrete luteinizing hormone (LH) & follicle stimulating hormone (FSH)

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4
Q

LH and FSH act on what?

A

testes and ovaries to release testosterone (or estrogen)

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5
Q

Estrogen

A

in females, it promotes development and maintenance of female characteristics and behavior, oocyte maturation, uterine proliferation; stimulated by FSH & LH

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6
Q

Testosterone

A

In males, promotes development and maintenance of male characteristics, behavior, and spermatogenesis; stimulated by LH

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7
Q

What is the ecological relevance of testosterone?

A
  • influences development of male secondary characteristics (crests, throat fans, color)
  • related to aggression
  • may both stimulate & retard growth
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8
Q

Sexual dimorphism

A

morphological differences between male and females
- e.g. male cuban anole lizards are larger than females because of faster growth rates
- growth rates largely determined by circulating levels of testosterone

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9
Q

Testosterone influences what?

A

aggressive behavior & competition among males for mates, thus, testosterone may be involved in sexual selection may influence mate choice (more blue)

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10
Q

Maternal provisioning of yolk testosterone influences what?

A

phenotypes of both males and female offspring that may influence fitness

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11
Q

What is correlated with testosterone levels in spiny lizards?

A

Mite parasitism; fitness cost of testosterone

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12
Q

Immunocompetence handicap hypothesis

A

increased levels of circulating testosterone cause an increase susceptibility to infection (reduced immune system)

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13
Q

What fitness benefits and costs does testosterone provide?

A

benefits: increased endurance, movement, and home range area
Cost: decreased growth rate & survival + increased parasitism

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14
Q

Muscle functions

A

locomotion, repositioning, internal movement, organism shape & form, support, protection, heat production

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15
Q

Type of muscle cells

A

cardiac, smooth, skeletal

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16
Q

which muscle cells are striated?

A

cardiac & skeletal

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17
Q

Which muscle cells are voluntary? Involuntary?

A

Voluntary: skeletal
Involuntary: smooth & cardiac

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18
Q

Skeletal muscle

A
  • bundles of fibers
  • attaches via connective tissue to bone
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19
Q

antagonistic muscle groups

A

muscles that cause opposing movements
e.g. bicep & tricep

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20
Q

Muscle organization

A

muscle - fiber bundles - fibers (cell) - myofibrils - sarcomere - actin (thin) + myosin (thick)

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21
Q

Muscle contraction produced by what?

A

Sliding filaments
1) myosin heads pull on thin filaments
2) Sarcomere unit shortens

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22
Q

Molecular interactions underlying muscle contraction (steps)

A

1) rigor conformation
2) breaking the cross-bridge: ATP binds & myosin releases actin
3) Hydrolyzing the ATP causes the angle of the myosin head to change
4) and Myosin head binds actin
5) Power stroke: fueled by phosphate leaving
6) Myosin unbinds ADP & remains bound to actin (rigor)

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23
Q

Thin filament

A

Actin: binding site for myosin

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24
Q

What are the regulatory proteins of actin (thin)?

A

tropomyosin & troponin

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25
Relaxed muscle state versus contracted
relaxed: No Ca2+ present in cytoplasm contracted: Ca2+ present
26
Calcium regulation of muscles
1) Ca2+ binds troponin 2) tropomyosin moves, exposing myosin binding sites 3) myosin head binds & makes power stroke 4) thin filament is moved
27
What triggers calcium release?
Excitation-contraction coupling
28
Excitation-contraction coupling steps
1) action potential: releases ACh 2) ACh binds ligand gated Na+ channels, Na+ enters = AP 3) AP depolarizes T-tubule: triggers voltage sensitive DHPR conformation change 4) Ryr Ca2+ channel opens & Ca2+ diffuses into cytoplasm 5) Ca2+ can now bind troponin and move tropomyosin 6) ACh is degraded: stops AP
29
How does Ca2+ get removed from the cytoplasm?
ATP-dependent Ca2+ pumps
30
Muscle twitch
mechanical response to action potential
31
Isometric twitch response
same length; tension developed is NOT sufficient to move load and muscle stays the same length
32
Isotonic
same tension; tension developed IS sufficient to move load & muscle shortens
33
what determines the tension by muscle?
frequency of action potentials
34
Summation
Action potentials in rapid succession (leads to twitches)
35
very high frequency stimulation produces what?
Tetanus = "fused" contraction
36
Muscular work depends on what?
ATP
37
ATP functions in muscle
1) binds myosin head: release actin 2) ATP hydrolysis: activates myosin cross-bridge 3) ATP hydrolysis: Ca2+ pumped into SR
38
How is ATP generated?
1) creatine phosphate 2) glycolysis 3) oxidative phosphorylation
39
Most ATP generated in a short-duration
Anaerobic glycolysis with phosphagen
40
All ATP is made by what in long-duration events?
catabolism
41
Tonic muscle fibers
- don't generate action potentials - slow cross-bridge cycling = long, sustained contraction with low energy cost
42
Twitch muscle fibers
- generate action potentials - most common - 2 main categories: slow oxidative & fast glycolytic
43
slow oxidative fibers (twitch)
- contract slow - fueled by oxidative metabolism - lots of aerobic enzymes - lots of mitochondria and myoglobin: makes fiber more resistant to fatigue
44
fast glycolytic (twitch)
- contract quick - powerful - fueled by glycolysis - lots of glycolytic enzymes - low mitochondria volume
45
motor unit
motor neuron + all skeletal muscle it stimulates
46
each axon branches innervate what?
multiple muscle fibers
47
each fiber receives synaptic input from what?
one motor neuron
48
when motor neuron fires action potential
all muscle fibers in the motor unit contract
49
Recruitment
increased muscle contraction force by increased number of active motor units
50
muscle force proportional to what?
cross-sectional area
51
Transport of gases =
passive
52
For O2 to move from environment into cells, conditions must be what?
favorable for passive transport
53
What are respiratory gases?
O2 & CO2 - principal gases consumed and produced by cellular respiration
54
Dalton's law
total pressure exerted by mix of gases = sum of pressures of individual gases PV = nRT
55
Partial pressure
individual pressure exerted by any particular gas in a gas mix Px = Fx x Ptot
56
Diffusion of gases dependent on what?
variation in partial pressures
57
Partial pressures of a gas is proportional to what?
the concentration of that gas in gas phase
58
Atmospheric pressure what with altitude?
decreases
59
Henry's law
Gases dissolve in liquids in proportion to their partial pressures Cx = A x Px
60
Henry's law depends on what?
- solubility in specific fluids - temperature - presence of other solutes (salinity)
61
Gases diffuse from what?
High Px to low Px
62
solubility what with increasing temperature?
decreases
63
solubility what with increasing salinity?
decreases
64
gases diffuse more readily through what than what?
air than water
65
Respiration via diffusion alone only possible at what?
<1mm distance
66
Gas transport is enhanced by what?
convective movement (bulk) - unidirectional flow - tidal flow
67
oxygen cascade of people
ambient air - alveolar gas - arterial blood - capillary blood - mitochondria
68
Solubility of Oxygen in blood =
low
69
What increases O2 carrying capacity by 50x?
metalloproteins
70
3 types of respiratory pigments
1) hemocyanins (copper) 2) hemerythins (iron) 3) hemoglobin
71
Hemocyanins
- copper - anthropods & molluscs - dissolved in hemolymph - blue when oxygenated
72
Hemerythins
- iron - brachiopods, annelids - inside coelomic cells - violet pink when oxygenated
73
Hemoglobin
- most common - verts, nematodes, annelids, insects, crustaceans - globin bound to heme (Fe) - carried by RBCs - red = oxygenated
74
Fetal hemoglobin
alpha-globin & gamma-globin
75
Adult hemoglobin
alpha-globin & beta-globin
76
Mammals Hb
fairly uniform in composition
77
Ectotherms Hb
mixes of 2,3, up to 10 different forms of Hb
78
O2 equilibrium curve
functional relationship between percent of binding sites oxygenated & partial pressure of O2
79
As PO2 drops, less & less of what is required to cause the same unloading of O2?
drop in partial pressure
80
myoglobin
- no cooperativity - 1 binding site - function independently
81
Hemoglobin
- cooperativity - partially bound Hb = increased oxygen affinity - 4 O2 binding sites/ molecule
82
cooperativity enhances what?
responsiveness of the process to changing PO2
83
No cooperativity =
low PO2 pressure necessary to release 80% of O2
84
Cooperativity =
unloads 80% of its O2 at much higher O2 partial pressure
85
O2 equilibrium curve Shape reflects what?
a trade-off between loading & unloading O2
86
O2 equilibrium curve height shows what?
how readily pigment binds to O2
87
High O2 affinity =
loads more easily = shift LEFT
88
low O2 affinity =
unloads more easily = shift RIGHT
89
Bohr shift
a right-shift in the normal curve due to decreased pH & an associated increase in CO2
90
decreased pH means shift
right
91
increased PCO2 means shift
right
92
Bohr effect typically what?
enhances O2 delivery
93
increased temperature does what to O2 affinity?
decreases O2 affinity; shift RIGHT
94
increasing temperatures promotes what?
O2 delivery during exercise
95
Specialized breathing structures
1) gills (external & internal) 2) lungs 3) cutaneous 4) tracheae
96
Respiratory surfaces must be what?
ventilated - reduces static boundary layers
97
Passive ventilation
nondirectional
98
Active ventilation
- tidal - unidirectional - nondirectional
99
Tidal gas exchange
1) fresh medium mixes with stale medium in the lung, so the PO2 of the medium @ the exchange surface with the blood is below that in the environment 2) O2 diffuses into the blood flowing along the exchange surface. The PO2 in the blood rises 3) The PO2 in blood leaving the lung remains lower than that in the exhaled medium
100
Countercurrent gas exchange is more efficient than what?
cocurrent gas exchange & Cross-current gas exchange
101
Area of gas exchange increases with what?
increasing body size
102
Thickness of gas-exchange is relatively constant with what?
increasing body size
103
Challenges to breathing in water
- H2O 1000 times denser than air - H2O has 100 times greater viscosity - solubility of O2 in water is 30x lower than in air
104
Advantages to breathing in water
- easier to eliminate CO2 - air breathing causes dehydration
105
Bucal-opercular pumping steps
1) buccal cavity (mouth) refilling causes buccal expansion, reducing the pressure, which draws in water. 2) Operculum draws water across gills 3) buccal pressure forces additional water across gills into opercular cavity 4) relaxation phase prior to next ventilation cycle
106
Ram ventilation
when swimming at 50-80 cm/s or greater, some fish simply open their mouth to ventilate gills
107
reliance on air increases as what?
dissolved O2 in habit decreases
108
Amphibians have what?
paired, unicameral lungs
109
How do amphibians ventilate?
buccopharyngeal pressure
110
simplest lung is
unicameral
111
Inhalation = what in snakes & what in lizards?
elastic expansion in snakes, intercostal ctx in lizards
112
Exhalation = what in snakes & what in lizards?
muscular compression in snakes, elastic relaxation in lizards
113
Upper respiratory tract
mouth, nasal cavity, pharynx, trachea
114
Lower respiratory tract
bronchi & lungs
115
Airways of the lungs
bronchioles & alveoli
116
Alveoli are what?
sites of gas exchange
117
The airways of human lungs
- tidal ventilation - highly vascularized - High SA - low diffusion distances

Fall 2022 (4 decks)

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