Animal Physiology Exam 1 Flashcards
1
Q
Animal physiology
A
the integrated study of how biological systems work; integrates multiple disciplines like evolution, chemistry, physics ect…
2
Q
What are the levels of biological organization? (bottom to top)
A
atoms, molecules, organelles, cells, tissues, organs, organ system, organism
3
Q
What’s at the core of the anatomical physiological wheel?
A
nervous/endocrine
4
Q
What surrounds the anatomical physiological wheel (connects everything)?
A
bloodstream
5
Q
What are the two main questions of animal physiology?
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(1) What is the mechanism by which a function is accomplished?
(2) What is the origin of that function?
6
Q
Mechanism
A
components of living organisms that enable animals to perform
7
Q
Origin
A
The evolutionary processes that conspired to produce a mechanism. The evolutionary significance of mechanisms
8
Q
What is the key process of evolutionary origin?
A
natural selection
9
Q
natural selection
A
increase in frequency of genes that increase fitness
10
Q
adaption
A
traits (or physiological mechanisms) that are products of evolution by natural selection
11
Q
What are the modes of natural selection?
A
1) directional selection
2) stabilizing selection
3) disruptive selection
12
Q
Directional selection
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selection favors 1 extreme of phenotype in a population
13
Q
Stabilizing selection
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extremes aren’t viable, so favors the intermediate
14
Q
Disruptive selection
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intermediate phenotype is not favored, but the extremes are; two phenotypes have high fitness; bimodal
15
Q
Individuals don’t experience what in their life-time? What does?
A
evolution; populations
16
Q
What indicates mode of natural selection?
A
changes in mean and/or standard deviation
17
Q
Thermal conformity
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both internal temp and external temp change 1:1
18
Q
Conformer benefits
A
energy efficient
19
Q
Conformer costs
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death & limited viable habitats
20
Q
Regulators
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able to maintain internal conditions despite change in external conditions
21
Q
Regulators benefits
A
can inhabit many places
22
Q
Regulators costs
A
takes a lot of energy
23
Q
Claude Bernard
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- Physiological regulation implies that function occurs best over a specified range of conditions
- 1st to recognize the stability of conditions humans maintain in their blood
- studied blood glucose
24
Q
Walter Cannon
A
- “internal constancy”
- regulatory mechanisms exist to maintain internal stability
- AKA homeostasis
25
What were Walter Cannons three postulates?
1) Nervous system preserves the normal conditioning of the body
2) Tonic activity (continuous) of a system can be modulated up & down
3) There are factors that have opposing effects = antagonistic controls
26
Hormone
endocrine system
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Nerves
nervous system
28
Hormones & nerves are apart of what?
long-distance response loop
29
Negative feedback loop
An upstream product or signal of a pathway inhibits an earlier step in that same pathway
30
Positive feedback
an upstream stimulus amplifies an initial response
e.g. Oxytocin & birth
31
Physiological timescales
timeframes in which physiology changes
32
Responses to external environment
Acute, chronic, evolutionary
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Changes in individuals
acute, chronic
34
Changes in populations
evolutionary
35
Chronic
phenotypic plasticity (acclimation); usually reversible; On a graph = elevation on the y-axis (differences between two lines)
36
Acute response on a graph
the slope
37
Evolutionary
- changes in populations & across generations
- adaptation
- irreversible change in genotype & phenotype
38
Physical properties are linked to what?
function
39
Chemical laws govern what?
molecular interactions
40
Electrical laws describe what?
membrane function
41
Body size influences what?
biochemical and physical patterns
42
Many traits scale in a systematic way with what?
body size
e.g. bigger animal = longer gestation
43
Isometric growth
- proportions remain constant
- each dimension is scaled up or down by same amount
- grow 1:1 fashion
44
Allometric growth
- changes in body proportions with changes in body size
- different rates of growth of different parts
- The proportions vary depending on the rates at which SA, Volume, & other physical parameters change with size
45
Size impacts what?
SA:V, thermoregulation, respiration, bone & muscle structure, water balance
46
As size gets bigger, the SA:V ratio what?
decreases
47
Higher SA:V ratio means what?
exchange occurs quickly compared to small SA:V
48
What constrains organisms to certain environments?
SA:V
49
What is the allometric equation?
Y = aX^b
50
What tells us if its isometric or allometric growth?
b = scaling exponent
51
If b = 1
isometric
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If b < 1
negative allometry (less than isometric expectation)
53
If b > 1
positive allometry (more than isometric expectation)
54
The scaling exponent (b) is only true when what?
comparing like dimensions
e.g. length to length
55
Isometry of head length vs body length
m1/m1, so b = 1/1 = 1
56
Isometry of head length vs body mass
m1/m3, so b = 1/3 = .33
57
Isometry of surface area vs body mass
m2/m3, so b = 2/3 = .67
58
scaling
the structural and functional consequences of changes in size of otherwise similar organisms
59
As SA increases, volume increases by what?
2/3 of SA (i.e. volume increases less rapidly)
60
Smaller objects have what relative to their volumes compared to larger objects?
larger SA
61
Volume increase more rapidly than does SA, so what?
SA:V decreases
62
Small differences on a log-log plot translate into what?
large differences when plotted arithmetically
63
By plotting on a log-scale, we can assess what 2 important aspects of the scaling relationship?
1) slope (b) = rate of change in trait relative to body size
2) proportionality coefficient (a) = y-intercept
64
An order of magnitude increase on the arithmetic scale represents what?
an increase of one unit on the log-scale
65
Kleiber's law
metabolic rate scales to the 3/4 power of body mass; varies with scale of study (individual vs across species)
66
What systems integrate and coordinate all other functional systems?
Nervous & endocrine
67
Basic unit of the Nervous system?
Neuron
68
Nerves are bundles of what?
neuron axons
69
Neurons and their support (glial) cells make up what?
Nervous system
70
How is information sent over long distances in the body?
Neurons and Endocrine cell
71
How does a neuron work?
signal - action potential along axon - release chemical (NT) into synaptic cleft/gap - NT binds receptors -response
72
How do endocrine cells work?
Synthesizes and secretes chemicals (hormones) into the bloodstream - travels to target - response
73
Response loop
stimulus - receptor - afferent pathway (sensory) - integrating center (CNS) - efferent pathway (motor) - effector - response
74
Functional classes of neurons
sensory (afferent) neurons, interneurons, motor (efferent) neurons
75
Neuroglia
glial cells
76
Neuroglia (glial cells) do what?
protect neurons & help them function
- insulate neurons from one another
- supportive framework
- involved in impulse transmission (communication)
77
What are the types of glial cells? Their locations?
CNS: oligodendrocytes, astrocytes
PNS: schwann cells
78
Oligodendrocytes
- CNS
- forms myelin sheath around axons
- insulates nerve fibers from extracellular fluid
- speeds up signal conduction
79
Astrocytes
- CNS
- most abundant glial cells
- supportive framework for nervous tissue
- regulate blood flow in brain
- regulate nerve growth
80
Schwann cells
- PNS
- surround axons of neurons (myelin sheath)
- entire cell wraps around axon - not just arms
81
Excitable cells
can change membrane potential
82
Resting membrane potential (RMP)
- about -70mV
- the "unexcited" state
- differs in voltage across the membrane
- membrane potentials first demonstrated in axons of the giant squid
83
Voltage
difference in charge
84
voltmeter
measures voltage
85
Reference electrode of the voltmeter is always what?
in extracellular fluid
86
What generates membrane potential?
selective permeability to ions
87
The intracellular fluid has what in respect to ion concentration?
High: K+ & A-
Low: Na+ & Cl-
88
The extracellular fluid has what in respect to ion concentration?
High: Na+ & Cl-
Low: K+ & A-
89
A- is what?
non-permeable anions
90
What helps maintain the concentrations of major ions?
active transport
e.g. Na+/K+ ATPase pump
91
What generates resting membrane potential?
1) Na+/K+ gradients
2) differential permeability (K+ moves faster)
3) Na-K ATPase pump moves ions against their gradients
92
Voltage declines with what?
distance
93
Why does voltage decline with distance?
leaky channels get rid of Na+
94
What are the changes in Vm in response to a stimulus?
RMP - depolarization - repolarization - hyperpolarization - RMP
95
Graded potentials
- local potentials
- provided by stimulus on dendrites or cell body
- amplitude proportional to stimulus strength
96
What determines whether a graded potential is weak or strong?
1) # of ion channels
2) distance current spreads
3) Threshold
97
Excitatory electrical charge
stimulus opens Na+ channels (depolarization)
98
Inhibitory electrical charge
stimulus opens Cl- (influx) or K+ (efflux) channels (hyperpolarization)
99
Action potentials
1) all or none
2) produced by graded potentials
3) always excitatory (depolarization)
4) propagates over long distances without decreasing in amplitude
100
What opens at threshold?
Voltage Na channels open
101
What opens at the peak of an action potential? what closes?
Open: K+ channels
Close: Na+ channels
102
What about K+ channels makes an action potential possible?
K+ channels are slow to open (why depolarization); they are also slow to close (why hyperpolarization)
103
What are the refractory period phases?
absolute & relative
104
absolute refractory phase
No action potential can be produced
105
relative refractory phase
Action potential can be produced but not "easily"
106
Conduction velocity depends on what?
axon diameter, myelination, temperature
107
Myelinated axons conduct what?
faster
108
Warmer neurons conduct what?
faster
109
Axons with increased diameters conduct what?
faster
110
Myelin sheath does what?
prevents ion leakage maintaining an action potential more efficiently
111
Synaptic transmission can be what? or what?
electric or chemical
112
Electrical synapse
- very rapid response
- electrical coupling of cells joined by gap junction
113
Chemical synapse
- takes longer
- must release a secondary messenger
114
Ionotropic receptor
- single molecule constitutes both the receptor and ion channel
- the receptor directly alters permeability to ions in post-synaptic cell
115
Metabotropic receptors
- trigger a signaling cascade of secondary messengers
- has a relatively slow, long lasting effects on synaptic processes
116
Excitatory post-synaptic potential
causes depolarization and repolarization
117
Inhibitory post-synaptic potential
causes hyperpolarization (makes AP generation harder)
118
Excitatory post-synaptic potential (EPSP)
- Na+ channels open (depolarization)
- NT = Ach or glutamate
119
Inhibitory post-synaptic potential (IPSP)
- Cl (influx) or K+ (efflux) channels open (hyperpolarization)
- NT = Gaba or glycine
120
What limits the graded potentials?
number of receptors & amount of NT released
121
EPSP summation
adding up post-synaptic potentials & responding to their net effect
122
Temporal summation
sends action potentials at high frequency; they add up and result in a new action potential
123
Spatial summation
involves more than 1 pre-synaptic cell interacting with one post-synaptic cell
124
Neurotransmitters
chemical messengers released by a nerve signal into synaptic cleft that bind to receptor on another cell & alters that cells physiology
125
Neurotransmitter categories
1) amines
2) amino acids
3) neuropeptides
126
Amines
- e.g. Ach, epinephrine, norepinephrine, dopamine, histamine
127
Acetylcholine (Ach)
- found in neuromuscular junctions and most synapses of the autonomic nervous system
- Excites skeletal muscle - EPSP (ionotropic)
- inhibits cardiac muscle - IPSP (metabotropic)
128
Amino acids
e.g. GABA, glutamate, glycine
129
GABA
IPSP (ionotropic)
130
Glutamate
EPSP (ionotropic)
131
Glycine
IPSP (ionotropic)
132
Neuropeptides
small chains of AA; Metabotropic
133
What works together (antagonistically) to control overall level of brain excitation?
GABA (IPSP) & Glutamate (EPSP)
134
An imbalance of GABA & Glutamate can be found where?
autism spectrum & anxiety disorders
135
Alcohol potentiates sedentary effects of what?
GABA
- increases GABA/glutamate ratio
- Sensations of relaxation and, at later stages, loss of control
136
Synaptic plasticity
synaptic properties change with time and activity
137
Presynaptic synaptic plasticity
changing rate of NT synthesis, storage, and release
138
Postsynaptic synaptic plasticity
sensitivity to NT can be increased or decreased under different circumstances
139
synaptic plasticity is thought to be a mechanism of what?
how neurons system function changes over time
- memory & learning
140
Synaptic potentials are what?
short-lived
141
Synaptic strength
amplitude of postsynaptic potential in response to pre-synaptic action potential
142
Facilitation "sensitive"
successive PSPs increase in amplitude in response to repeated pre-synaptic action potentials
143
Anti-facilitation
successive PSPs in a series decrease in amplitude
144
Facilitation is pronounced after what?
Tetonic stimulation of pre-synaptic neurons
145
posttetanic potentiation
extended enhancement of synaptic response
146
What regions of the brain are associated with memory & learning?
hippocampus & cerebral cortex
147
Habituation
decrease in intensity of reflex response to stimulus
148
Sensitation
prolonged enhancement of reflex response to stimulus
149
long-term potentiation in hippocampus
tetonic stimulation - long-term potentiation
- more channels = greater response
150
Chemical signals act over what in the body?
short & long distances
151
Types of signals in the body that travel short and long distances
- neuron: pre-synaptic to post-synaptic
- non-neural endocrine cell
- neurosecretory cell
- local paracrine & autocrine signals
152
What are the three chemical classes of hormone?
1) steroid hormones
2) peptide (protein) hormones
3) amine hormones
153
Steroid hormones
- synthesized from cholesterol
- sex hormones, stress hormone/metabolic hormones
- secreted by gonads, adrenal cortex, skin & placenta
- In anthropods: molting hormones
- lipid soluble
- receptors located inside target cells
154
Peptide hormones
- structured from chains of amino acids
- in verts: antidiuretic hormone, insulin & growth hormone
- In inverts: gamete-shedding hormone (sea stars), diuretic hormone (insects)
- vary enormously in molecular size
- water soluble
- receptors located on surface of target cell
155
Amine hormones
- modified amino acids
- catecholamines (Tyrosin derivative): NE, epi, dopamine
- Iodothyronines (Tyrosin derivative): T3, T4 = thyroid hormones
- Melatonin (Tryptophan derivative)
- Melatonin and catecholamines = water soluble
- Iodothyronines = lipid soluble
156
Hormones produce what?
biochemical changes in target cells
157
What are the 3 receptor types that mediate hormone action?
1) intracellular receptors
2) G-protein coupled membrane receptors
3) enzyme linked membrane receptors
158
Lipid-soluble hormones bind to what?
intracellular receptors
159
Lipid soluble hormones and their receptors act as what?
transcription factors
160
Steroids & Iodothyronines (lipid soluble hormones) do what?
interact directly with a cell's DNA to alter gene expression
- directly influences protein synthesis of target cell
- process takes time
161
Water-soluble hormones (peptides & catecholamines) bind to what?
membrane receptors
162
Water-soluble hormones do what?
mediate hormone action by changing membrane permeability or by activating secondary messengers via G-proteins
163
What are the 2 major controls of hormone secretion?
1) neuron control of secretion by neurosecretory cells
2) neurosecretory control of secretion by endocrine cells
164
Anterior pituitary
endocrine tissue; non-neural endocrine cell
165
Posterior pituitary
continues with hypothalamus (nervous tissue); neurosecretory cell
166
In mammals, what two hormones are released in the posterior pituitary gland?
oxytocin, vasopressin
167
Anterior pituitary and neurosecretory control of secretion by what?
endocrine cells
168
What are the two groups hormones are categorized into?
1) influence non-endocrine tissues
2) influence endocrine tissues (tropins) = tropic hormones
169
Hypothalamus-anterior pituitary-thyroid axis
TRH - TSH - thyroid hormone
170
HPA
Hypothalamus- pituitary- adrenal cortex
171
Glucocorticoids
- steroid hormones
- secreted by adrenal cortex
- cortisone, cortisol, corticosterone
172
What activates the release of glucocorticoids?
stressful or challenging conditions
173
What allows a generalized response to challenging/stressful conditions?
adaptation
174
Stressors
wounding, thermal extremes, forced vigorous exercise, social conditions
175
What occurs during early phases of stress response?
- low levels of catecholamines and CORT
- immune function enhanced
- immune response often causes inflammation
176
What occurs at higher concentration of CORT?
- has anti-inflammatory effects
- helps keep immune system in check
177
What can chronic stress cause?
- catabolic actions can cause muscle wasting & bone thinning
- suppression of immune system - increased susceptibility to infections & disease
- suppresses reproductive functions
- permanent alteration of GC receptors in brain (PTSD)
178
Because glucocorticoids are involved in the stress response, baseline levels of what have been used as an index of stress?
circulating CORT
179
Core of the CORT-fitness hypothesis
higher baseline levels of CORT interpreted as an individual or population in worse condition (lower relative fitness) than those with lower levels of CORT
180
Provisioning what is more stressful and requires more energy?
more or larger babies
181
What are the 2 central ideas of the cort-fitness hypothesis?
1) Baseline cort increases with increasinnng environmental challenge (stress)
2) Fitness should decline with increasing environmental stress
182
Density triggers what that increases adaptive offspring growth in a wild mammal?
maternal hormones
183
Early stress can what?
re-program the HPA axis and alter the efficacy of the stress feedback loop (less efficient)
184
Alteration of gene expression
epigenetics
185
What is a common observed neuroendocrine symptom of depression?
dysregulation of the HPA axis
