Animals Flashcards
1
Q
Can polar molecules cross lipid membrane
A
no, needs channels to cross
2
Q
what are the different types of membrane transport
A
passive diffusion
facilitated diffusion
primary active transport
secondary active transport
3
Q
what is passive diffusion
A
moving down concentration gradient
passive
4
Q
what is facilitated diffusion
A
moving down concentration gradient , but with help (ex: membrane channels)
passive
5
Q
what is primary active transport
A
transport of solute linked to the splitting of ATP
ex: sodium pump
6
Q
what is secondary active transport
A
uses gradient set up by primary active transport
7
Q
explain resting state of sodium pump
A
3 Na+ out
2 K+ in
uses ATP and breaks it down to ATP
higher [Na] outside
higher [k] inside
more negative inside cell
8
Q
what is membrane potential
A
difference in charge between inside and outside of cell
9
Q
what makes resting cell more negative on inside
A
K+ leak channels
10
Q
what maintains resting membrane potential
A
sodium pump and potassium leak channels
11
Q
what causes differences in membrane potentials
A
changes in permeability
12
Q
what is a resting membrane potential
A
= normal membrane potential of non-excitable cell
13
Q
what is an action potential
A
when sum pf graded potentials reach a threshold potential
14
Q
what are graded potentials
A
changes in membrane potentials
15
Q
what happens when Na+ channels open
A
Na+ moves into cell = becomes less negative
= depolarization
16
Q
what happens when K+ channels open
A
K+ moves out = move negative
= hyper polarization
17
Q
what is equilibrium potential
and will there be net ion movement
A
membrane potential at which the chemical gradient balances the electrochemical gradient
no net ion movement
18
Q
are graded or action potentials better for long distance
A
action
graded get weaker with distance
19
Q
what are the types of gated ion channels and explain them
A
ligand-gated channels: change permeability in response to a ligand neurotransmitter)
voltage gated ion channel: change permeability in response to change in membrane potential
20
Q
what causes repolarization and hyperpolarization
A
voltage gated K+ channels open and close slower than NA+ channels
21
Q
what happens when voltage reaches -55 mV in Na+ voltage channels
A
Na rushes into cell, causes depolarization
when it moves away from -55mV channel closes
22
Q
what happens when voltage reaches +30 mV in K+ voltage channels
A
K+ moves out
causes repolarization and hyperpolarization
23
Q
does the magnitude of a graded potential vary ?
For action potential ?
A
graded; yes
action: no
24
Q
what causes graded potentials? Action potentials ?
A
graded: various ion channels
action: voltage gated ion channels
25
what happens during absolute refractory period
new action potential cannot occur
repolarization phase
26
what is the relative refractory period
greater stimulus is needed for new action potential
hyperpolarization phase
27
how do action potentials affect ion gradient? what restores them?
slightly reduces ion gradient
restored by sodium pump and potassium leak channels
28
are action potentials all or none?
yes
29
what effect do excitatory neurotransmitters have ?
move membrane potential towards threshold potential
30
what effect do inhibitory neurotransmitters have
move membrane potential away from threshold potential
ex: k+ leaving or Cl- entering
31
what is SCN94 encode? and what would a loss/gain of function do
codes for for a subunit of a voltage gated Na+ channel
loss: insensitivity to pain. loss of smell
gain: extreme pain disorder
32
what are the categories of neurotransmitters
acetylcholine
monoamines (noradrenaline, dopamine, serotonin )
amino acids (glutamate, GABA)
peptides (endorphins, enkephalins, substance p)
33
what does ACh do and is it excitatory or inhibitory
acetylcholine is used at the neuromuscular junctions, triggering the firing of motor neurons and affecting voluntary movements.
excitatory
34
what does noradrenaline do and is it excitatory or inhibitory
norepinephrine increases heart rate and blood pumping from the heart. It also increases blood pressure
increases alertness
can be either
35
what does dopamine do and is it excitatory or inhibitory
Dopamine plays a key role in movement and affects motivation, perception of reality, and the ability to experience pleasure
excitatory or modulatory
36
what does serotonin do and is it excitatory or inhibitory
Serotonin controls your mood and is responsible for happiness
inhibitory or modulatory
37
what does glutamate do and is it excitatory or inhibitory
glutamate is the most abundant excitatory neurotransmitter
glutamate is the principal mediator of cognition, emotions, sensory information, and motor coordination, and is linked to the activity of most other neurotransmitter systems
38
what does GABA do and is it excitatory or inhibitory
primary inhibitory neurotransmitter for the central nervous system
ethanol mimics response to GABA
39
What effect do peptides tend to have
opiates bind to a stimulate receptors
naloxone blocks receptors
40
how do drugs that prevent reuptake of neurotransmitter affect its activity
increase
41
what does it mean for neurons to be excitable cells
membrane potential can change in cell in response to a signal
42
what do dendrites do
convert chemical signals to electrical signals
43
what does cell body do in a neuron
integrate incoming signal
(integrate = decide whether or not to send signal)
happens at axon hillock
44
what does axon do
conduct electrical signal
45
where does signal transmission occur
axon terminal
across a synapse
46
what is a synapse
are the junction where neurons communicate
47
where do graded potentials occur and where are they summed
dendrites
summed at axon hillock
48
when does signal conduction occur along axon
when graded potentials sum to the threshold potential
= action potential
49
what do myelin sheaths do
insulate axon
allow signal to move faster
50
what part of action potential carries the information
frequency
51
can action potentials travel long distances without decay
yes
52
what are the factors that influence speed of conduction
membrane resistance = resistive to leak
(more membrane resistance = less leaks = depolarization travels further = faster)
intracellular resistance = resistance to spread
(greater intracellular resistance = depolarization travels less far = slower)
length constant : larger it is, the further depolarization travels = faster
53
how does bigger diameter influence speed of conduction and membrane and intracellular resistance
bigger diaper = lower intercellular resistance = depolarization travels further = faster
digger diameter = lower membrane resistance (normally would = slower but intracellular resistance has greater effect in this instance)
54
how do myelin sheaths affect length constant
increases membrane resistance = increases length constant
55
how are signals transmitted across synapse
from presynaptic cell to postsynaptic cell usually via chemical messenger (neurotransmitter)
56
what regulates neurotransmitter release
Calcium
action potentials (cause voltage gated Ca2+ channels to open)
57
what are the steps for how action potential triggers release of neurotransmitter
1. action potential arrives at synaptic cleft
2. voltage gated Ca2+ channels open (Ca2+ enters presynaptic cell)
3. synaptic vesicles fuse with postsynaptic membrane and release neurotransmitters
4. Ion channels in postsynaptic membrane open when neurotransmitters bind to receptors
5. ion channels in postynaptic membrane close when neurotransmitters unbind from receptors
58
do all neurotransmitter bind to ligand - gated ion channels
no
some bind to receptors that produce secondary messengers
59
how do G protein receptors work
1. G protein inactive (bound to GDP)
2. signal receptor complex changes conformation after ligand attaches (G protein exchanges GDP for GTP, becomes activated)
3. activated g-protein binds to an enzyme and induces production of secondary messenger which triggers a response
60
what are SSRIs
selective serotonin reuptake inhibitors
used as antidepressant
61
what are the types of neurotransmitter receptors
ionotropic receptors: typically ligand gated ion channels where ion passes through channel after it opens after a ligand binds to it
Metabotropic receptors: dont form an ion channel, instead use a signal transduction mechanism (G-proteins)
62
what is a biogenic amine receptor
mostly belong to g-protein coupled receptor family
bind adrenaline and noradrenaline
63
what does the CNS comprise
brain and spinal cord
64
what does the peripheral nervous system comprise
autonomic nervous. system
somatic nervous system
65
what is the autonomic nervous system
controls involuntary bodily functions and regulates glands
66
what is the somatic nervous system
controls muscle movement and relays info from eyes, ears, skin, etc..
67
what is the autonomic nervous system divided into
sympathetic : fight or flight
parasympathetic: rest and digest
68
what is a ganglion
grouping of neuronal cell bodies
69
what is a nuclei
grouping of cell bodies in brain
70
what are tracts
grouping of axons in brain
71
what are nerves
what neurons are organized into outside of integrating centres
72
what is an afferent neuron
arriving at Brian
sensory receptor --> brain
73
what is a efferent neuron
exiting brain
brain --> muscles and glands
74
what is white matter
bundles of axons and myelin sheaths
75
what is grey matter
neuronal cell bodies and dendrites
76
how is white/grey matter organized in brain
grey on outside , white on inside
77
how is white/grey matter organized in spinal cord
grey on inside , white on outside
78
how do parasympathetic and sympathetic nervous systems balance
dual intervention
antagonistic
basal tone (always on)
79
how do parasympathetic and sympathetic nervous systems balance
dual intervention
antagonistic
basal tone (always on)
80
what are the parts of the hindbrain
pons
cerebellum
medulla oblongata
81
what does the pons do
connects rest of brain stem to cerebral cortex
coordination center for signals and communication between brain hemispheres and spinal cord
82
what does the cerebellum do
coordinates our senses with responses from our muscles
allows most of your voluntary movement
helps maintain balance
83
what does the medulla oblongata do
where brain transitions to spinal cord
contains the control centre for autonomous vital functions and involuntary refluxes
84
what does the midbrain do
serves connection between hindbrain and forebrain
topmost part of brainstem
85
what does cerebrum/ cerebral do
where most important brain functions occur (thinking, language, interpreting, processing senses
86
what does the hypothalamus do
keeps body at homeostasis (regulates blood pressure, temperature, etc...)
87
what does thalamus do
processes non-smell senses before they're sent to cerebral cortex
88
parts of forebrain
thalamus
hypothalamus
cerebrum/cerebral
89
what is adrenal medulla innervated by and what does it secrete
sympathetic nervous system
adrenaline and noradrenaline
90
what are the meninges
3 layers of membranes and fluid that protects brain and spinal cord
91
what is the blood brain barrier
barrier between brain's capillaries and brain tissue
provided defence against pathogens in blood
tight junction: fluid from blood can't squeeze by cells into brain, must enter through cells
92
what is the somatic motor pathway
controls only skeletal muscle
93
how does sliding filament model work
1. myosin head (which has ATP) binds to actin
2. actin pulled towards center by myosin (this releases ADP and P)
3. New ATP binds to myosin
94
what are the regulatory proteins for muscle contraction
tropomyosin and troponin
95
why is myosin an ATPase
converts energy from ATP to mechanical energy
96
what is a myocyte
muscle cell
97
what types of muscle are striated
cardiac and skeletal
98
what makes a muscle striated
thick and thin filaments are arranged into sarcomeres
99
what are sarcomeres organized into and then what are those organized into
sarcromeres are arranged into myofibrils
myofibrils are arranged into myofibers (skeletal) or cardiomyocytes (cardiac)
100
what causes depolarization in skeletal muscles
neurotransmitters
101
how do action potentials trigger muscle contraction
1. action potential arrives at end of motor neuron (triggers release of Ach)
2. Ach binds to Ach receptors on muscle cell (triggers depolarization, which leads to action potential in muscle cell)
3. action potential propagates across plasma membrane
4. calcium channels open and calcium is released into cytoplasm of muscle cell
5. sarcomeres shorten
102
do skeletal or cardiac muscles depolarize and depolarize quicker
skeletal
103
what does myogenic mean
contractile activity is produced independent of any neural mechanism
104
what does neurogenic mean
contractile activity is caused by neural mechanisms
105
in vertebrates is contraction all or nothing?
yes
106
how does contraction work in invertebrates
contract in response to graded potentials
107
what are t tubules
transverse tubules formed by inward extensions of sarcomeres
allow electrical impulses deeper in cell
in striated muscle
108
what is myoglobin
protein in striated muscle that supplies o2
109
what is glycolysis
breaking down glucose to make energy
doesn't require o2
110
what are the muscle types
appearance : striated or smooth
excitation: myogenic or neurogenic
in striated muscle only:
metabolism: oxidative vs glycolytic
myoglobin: white vs pink
111
what does slow fibre skeletal muscle have
red , high [myoglobin], derives most atp from aerobic respiration , many mitochondria
fatigue slowly
112
what does fast fibre skeletal muscle have
white, low [myoglobin] , derives most atp from glycolysis
few mitochondria
fatigues quickly
113
what does intermediate fibre skeletal muscle have
pink high [myoglobin], derives atp from aerobic respiration and glycolysis , many mitochondria
intermediate fatigue
114
what is there a trade off for between mitochondria and myofibrils for
space
115
is pennate or parallel arrangement of sarcomeres have more force? contract more ?
pennate : more force , contract less
parallel: less force : contract more
116
where is smooth muscle
in arteries, intestines, uterus
117
does smooth muscle have sarcomeres or thin/thick filaments
sarcomeres: no
think/thick: no (just not uniformly aligned)
118
what is single unit smooth muscle and what is it good for
electrically connected via gap junction
good for coordinated contractions
ex: in small blood vessels ,gastrointestinal tract
119
what is multi- unit smooth muscle and what is it good for
cells aren't electrically connected
allows for finder muscle contractions
ex: eye muscles, large blood vessels
120
what controls smooth muscle
autonomic nervous system
121
does smooth muscle have troposin? and if not what?
no
instead it has calmodulin (which activated myosin by regulated myosin light chain kinase)
122
what are the steps of electrical activation of heart
1. signal originates at SA node
2. signal spreads over atria (atria contract)
3. signal is delayed at AV node
4. signal spreads along conducting fibres to bottom of ventricle then to top (ventricles contract)
5. ventricles relax
123
is a vertebrate heart myogenic or neurogenic
myogenic
124
where is pacemaker located
SA node
125
what is unique about pacemaker K+ leak channels
K+ permeability decrease over time
126
what is a funny current
slow inward movement of sodium in pacemaker
127
what happens when pacemaker potential reaches threshold voltage
voltage gated Ca2+ channels open
when they close and K+ channels = repolarization
128
where is action potential initiated in heart
SA node
129
what is heart controlled by
nervous and endocrine system
pacemaker potentials are effected by ion channels which are affected by nerves and hormones
130
what does HCN4 code for and what does loss of function lead to
codes for a subunit of funny channel
loss: low heart rate
131
why does cardiac muscle take longer to repolarize
unlike skeletal muscle, doesn't do sustained contraction
heart needs to relax to fill with blood
volte gated Ca2+ channels open and delay it
also Na+ channels stay open longer
132
what is/causees vasoconstriction
contracting of muscles around blood vessel to make it narrower
sympathetic
133
what is/causes vasodilation
relaxation of muscles around blood vessel to make it wider
parasympathetic
134
how does smooth muscle affect walls and what does this mean for capillaries
makes them thicker = worse for exchange = capillaries dont have them
135
are marine environments hypo or hyper -osmotic
what does that mean
hyper osmotic
will loose water gain ions
136
are freshwater environments hypo or hyper -osmotic
what does that mean
hyposmotc
loose ions gain water
137
adaptations skin has for osmoregulation
polarized - different transporters of basal and apical side
microvilli
many mitochondria
138
how do gills work in salt water
counter gain of ions through diffusion (loose ion through active transport out)
at basal side: Na+/K+-ATPase pumps Na+ out of cells into blood
Na+ gradient is used to bring Cl- into cell by NKCC receptor
at apical side: Cl- leaves into environment, making outside negative, which Na+ is attracted to, so it leaks out between cells
139
what is the process of salt excretion in shark rectal gland
1. Na+/K+ -ATPase pumps Na+ into cell (creating electrochemical gradient favouring the diffusion of NA in cell and k out
2. Na/K/Cl cotransporter powered by Na gradient brings these ions from interstitial fluid into cell
3. Cl diffuses into environment along its electrochemical gradient and K diffuses into interstitial fluid
4. Na diffuses into environment along electrochemical gradient though spaces between cells
140
how do gills work in freshwater
counter gain of water , loss of ions
apical side: H+ ATPase creates favourable gradient for na to flow through channels. HCO3- leaves for Cl in
basal side: cl- leaves cell into blood
na/k atpase pumps na out of cells into blood
141
how to gills work in fish that go in fresh and salt water
- na/cl/k cotransporter can change locations
na /k can stay in place
amounts of na/k atpase and na/k/cl cotranspoter can change
142
why do saltwater gills have to work harder
saltwater fish cannot get rid of nacl at kidney
freshwater fish can get rid of water at kidney
143
what does glomerus/bowmans capsule do
blood filtered through creates primary urine
144
what species have loop of henle
mammals and birds
145
what happens at each part of loop of henle
ascending limb: permeable to nail but not water, so nacl is reabsorbed
decsending limb: permeable to water but not nail so water is reabsorbed
146
what does collecting duct do
reabsorb some of the nacl and water that was missed
147
when is urine more dilute than blood
in loop of henle
since na is pumped out
148
when is urine more concentrated than blood
collecting duct
water is absorbed
