exam Flashcards
(283 cards)
1
Q
How many phyla in ecdysozoa?
A
8
2
Q
What is phylum nematoda?
A
the roundworms
3
Q
what is phylum arthropoda?
A
the arthtropods
4
Q
describe the phylum nematoda
A
thin, non-segmented worm
bilaterally symmetrical
cephalized
lack appendages
5
Q
describe nematode morphology
A
pseudocoelomates with a complete gut
lack specialised circulatory, excretory and respiratory systems
pseudocoelum acts as hydrostatic skeleton
longitudinal muscles run along body wall
6
Q
How do nemotodes reproduce?
A
sexual reproduction, internal fertilization, egg laying
can self fertilize - reproductive assurance but inbreeding
7
Q
How do nematodes develope?
A
direct development
many display cell constancy
8
Q
Describe nematode growth
A
moult
some species switch between alternative developmental pathways
9
Q
What is the Dauer stage in nematodes?
A
alternative juvenile stage specialized for long-term survival
10
Q
What is phenotypic plasticity?
A
developemental switches are triggered by the environment
11
Q
What is the most studied animal?
A
Caenorhabditis elegans
12
Q
How do nematodes feed?
A
bacteria, fungi, microbes
carnivorous
parasitic
13
Q
describe the phylum arthropoda
A
segmented
hard exoskeleton
articulated appendages
14
Q
Describe the arthropd body plan
A
repetitive, segmented
head, thorax, abdomen
15
Q
Describe the arthropod skeleton
A
cuticle serves as a rigid exoskeleton
movable, jointed appendages - allows movement while still being protected in exoskeleton
16
Q
describe the arthropod circulatory system
A
gut and other organs in pseudocoelomic cavity (hemocoel)
hemolymph (fluid in hemocoel) transports nutrients to organs
open system
17
Q
What are the chelicerata?
A
spiders, scorpions, mites
18
Q
what are the myriapoda?
A
centipedes, millipedes
19
Q
what are the pancrustacea?
A
crustaceans, insects
20
Q
Are wings appendages or cuticle?
A
cuticle
21
Q
describe arthropod reproduction
A
sexual reproduction
variation in reproductive strategies
asexual parthenogenesis seen in several groups
22
Q
What is haplodiploidy?
A
an unusual sexual system seen in several groups
females born of sexual reproduction - diploid genome
males - born of asexual parthenogenesis - haploid genome
23
Q
What group is haplodiploidy most prominent in?
A
hymenoptera
24
Q
What does haplodiploidy result in?
A
increased genetic relatedness between sisters
25
Describe arthropod development
develop in a protective egg - terrestrial species
free-living larvae - aquatic species
moulting
pause/delay development
metamorphosis
26
what is diapause?
pausing development based on environmental triggers
27
what is holometabolous?
major body plan reorganization occurs during pupal stage
28
what is hemimetabolous?
relatively subtle changes with no pupal stage
29
What groups are in the deuterostomia?
hemichordata
echinodermata
chordata
30
What is the phylum echinodermata?
sea stars, sea urchins, sea cucumbers
radially symmetrical
crawls on sea floor w/ tube feet
31
describe echinoderm morphology
radially symmetrical
no discrete brain
skin has biomineralized spines and skeletal plates for protection
complete gut, mouth on bottom, anus on top
no gills, heart or nephridia
32
Are sea cucumbers radially or bilaterally symmetrical?
bilaterally
33
describe echinoderm reproduction
separate sexes
broadcast spawning
sea urchins are model systems for sperm-egg interactions and deuterostomal development
asexual reproduction via splitting and regeneration
34
describe echinoderm development
most species have free swimming larvae that metamorphose into benthic adult stages - indirect developement
early stage larvae are bilaterally symmetrical
35
describe the chordate body plan
bilaterally symmetrical
has a:
- notochord
- dorsal, hollow nerve tube
- pharyngeal (gill) slits or clefts
- muscular, post-anal tail
36
What is the notochord?
long, flexible cartilage-like rod
provides skeletal support
37
What is the nerve cord?
hollow tube built from ectodermal cells
develops into spinal cord and brain in vertebrates
38
What are the pharyngeal slits/clefts?
groves or openings in the pharynx
provide channels between outside and back of mouth
39
what are cephalochordates?
a groups of small benthic, marine filter feeders
has entire length notochord for whole life
40
what are tunicates?
a group of sessile, marine, filter-feeders
sea squirts
adults sessile - no notochord
41
When did vertebrates arise?
~530MYA
cambrian
42
what are the key features of vertebrates?
Rigid, internal skeleton (dorsal, jointed vertebral column replaced the notochord)
2 pairs of appendages
Anterior skull & large brain
Internal organs suspended in large coelom
Advanced circulatory system
43
What are some shared characteristics between jawless fish and vertebrates?
skull, brain, eyes, and other sensory organs
two or more clusters of Hox genes
neural crest
44
What are the myxini?
hagfishes
45
what does anadromous mean?
inhabit various marine and freshwater habitats
46
What are petremyzontida?
lamprey
andromous jawless vertebrates
47
What were the first vertebrates with mineralized skeletal elements in their mouth and pharynx?
conodonts
48
do chondrichthyes have fin rays?
no
49
what is an example of a fossil gnathostomes?
placoderm fish
50
what is the difference between gnathostomes and acathodians?
acanthodians have spiny fins
51
What are the 4 gnathostome lineages that remain today?
Chondrichthyans
Ray-Finned Fishes
Lobe-fin fishes
Tetrapods
52
What are 3 common chaacteristics of gnathostomes?
additional duplication of Hox genes
enlarged forebrain
lateral line system
53
What are chondrichthyans?
sharks, rays, chimearas
54
Describe how chondrichthyans reproduce?
males have claspers
eggs fertilized internally
some sharks cannibalise other embryos in utero
55
what does oviparous mean?
eggs hatch outside the mother’s body
56
what does ovoviviparous mean?
the embryo develops within the uterus and is nourished by the egg yolk
57
what does viviparous mean?
the embryo develops within the uterus and is nourished through a yolk sac placenta from the mother’s blood
58
what 2 features do nearly all osteichthyans have?
Breathe water over gills protected by an operculum
Control buoyancy with an air sac known as a swim bladder
59
What are 5 key features of ray-finned fish?
Calcified endoskeleton (calcium phosphate), rather than cartilage
Fin ‘rays’ (thin bones)
Gills in single chamber with 1 flap (not multiple slits) - operculum
Scales cover skin (protect & down drag)
Swim bladder aid in buoyancy
60
Do sharks have swim bladders?
No
Forward motion generates lift via tail & pectoral fins
Low density lipids in shark livers (= 5-25% of body mass)
61
62
What kind of circulatory system do fish have?
single circuit
63
What kind of circulatory system do mammals have?
double circuit
64
What is anatomy?
the branch of science concerned with the bodily structure, especially as revealed by dissection
65
what is morphology?
the form of living organisms, and relationships between their structures
66
What are sarcopterygians?
Actinista + Dipnoi + Tetrapods
67
What are 3 key features of actinista?
(ceolacanths)
large fish (60kg+) w/ fleshy fins
Muscles outside the body, similar to tetrapod load-bearing limbs
Some limb bones (pectoral) homologous to tetrapod limb bones
68
When was the actinistia fossil found?
70 MYA
69
What are dipnoi?
lungfishes
Monophyletic group
Powerful jaws, crushing teeth
Paired fins, with thick central lobe with bone & muscle
Found in warm, stagnant, freshwater
70
How do lungfish breathe?
lungs filled with gulping air at the surface
71
What is aestivation?
A state of dormancy or torpor during the summer
72
What is a pleisomorphic character?
present in ancestor
73
When did swim bladders arise?
in later ancestor of ray-finned fishes
74
What are the advantages of becoming terrestrial?
Air has many advantages for gaining O2
Less energy (less resistance) required for motion on land
O2 in water can be zero if stagnant
75
What are the disadvantages of becoming terrestrial?
GRAVITY
Evolution of new locomotory system required (body support) i.e. limbs
76
What are tetrapods?
gnathostomes with limbs
77
what are Panderichthys?
Tetrapod-like: begin to see evolution of digits and radial bones within the fins
No dorsal fin, shallow water
Dorso-ventrally flattened
Ready for a walk
78
what is a tiktaalik?
Intermediate between fish with fins, and tetrapods with limbs = “fish-apod”
79
what is an acanthostega?
Four limbs with well developed digits (polydactyl)
8 on Acanthostega
Gills & lungs
80
what are the true terrestrial adaptations?
True walking limbs (ankle and wrist joints) and feet with digits (from jointed fins)
Fully developed pectoral girdle, free form the skull
Retained ‘lungs’ for air-breathing
Ears for detecting airborne sounds
Using land-based food sources
81
What does amphibian mean?
'both ways of life'
82
Do amphibian larvae have lungs or gills?
gills (water)
83
Do amphibian adults have lungs or gills?
lungs and skin (air and water)
84
How do amphibians reproduce?
external fertilization
eggs need moist environment
85
what is metamorphosis?
the process of transformation from an immature form to an adult form in two or more distinct stages
86
what animals are in order apoda?
includes caecilians, which are legless and resemble worms
87
what animals are in order urodela?
includes salamanders & newts, which have tails
88
what animals are in order anura?
includes frogs and toads, which lack tails
89
what is matrophagy?
of tearing skin from the mothers body, providing nutrition
90
what are amniotes?
group of tetrapods whose living members include reptiles, birds, and mammals
91
what is an amniotic egg?
contains membranes that protect the embryo
have an ‘internal aquatic environment’
92
What kind of eggshells do birds have?
calcareous
93
What kind of eggshells do reptiles have?
leathery and flexible
94
What kind of eggshells do mammals have?
no eggshells (mostly)
develop in mothers body
95
what are the 4 'extra-embryonic' membranes?
Amnion
Chorion
Allantois
Yolk Sac
96
what is the amnion?
surrounds embryo, secretes fluid (hydraulic support)
97
what is the chorion?
encloses embryo, role in gas exchange
98
what is the allantois?
sac for storage of waste products
99
what is the yolk sac?
encloses yolk – feeds the embryo via blood vessels
100
What are the disadvantages of the amniotic egg (cleidoic egg)?
Air is more thermally variable than water (kept at a warm steady temperature)
Must have internal fertilization (morphological and behavioural adaptations)
Usually requires more parental care than fish or amphibians
Relatively expensive to produce
101
what are the 2 lineages of amniotes?
reptiles
synapsids
102
how are amphibians and reptiles different?
Scales (contain keratin) – Protects from abrasion & water loss
Internal fertilisation prior to laying (shelled) eggs on land
103
what is a paraphyletic taxon?
some, but not all descendants of a single ancestor
104
what is polyphyletic taxon?
the most common ancestor is NOT part of the group
105
what is a monophyletic taxon?
all descendants of a single ancestor
106
what is a diapsid?
diversified soon after early reptiles & evolved into two main lineages:
lepidosaurs
archosaurs
107
what are lepidosaus?
tuataras, lizards, and snakes
108
what are archosaurs?
the turtles, crocodilians, pterosaurs*, dinosaurs*and birds
109
what are squamates?
snakes and lizards
110
what are 5 key features of lepidosaurs?
Very horny scales – strongly desiccation resistant
Outer layer of skin is shed
Lung ventilation – ribs used as bellows
Chambered heart – partial separation of oxygenated blood (lung) and deoxygenated blood (body) – allows ACTIVE metabolism
Reduction of the limbs is common
111
what are the chelonians?
turtles and tortoises
112
what era did dinosaurs exist?
mesozoic era
first evolved in the triassic ~ 150MY
mass extinction at cretaceous-tertiary boundary
113
What are the 2 dinosaur groups and how do you distinguish between them?
ornithischia
saurischia
distinguished by the pelvic girdle/hip
114
How are birds adapted to flight?
evolved 'hollow' bones (air-filled honeycomb)
Lack urinary bladder
Small gonads
Females with only one ovary
Loss of teeth
115
What are the 4 key features of feathers?
Keratin (modified scales)
Lightweight
Strong
Structurally complex
116
are most reptiles ectothermic or endothermic?
ectothermic
117
what does ectothermic mean?
body temp dependent on external source of heat
118
are most birds ectothermic or endothermic?
endothermic
119
What birds are ratites?
flightless birds
ostriches
emus
Penguins
some species of rails
ducks
pigeons
120
What are the 3 key traits of mammals?
Mammary glands (milk production)
Hair
Fewer, but more differentiated teeth (more varied diet)
121
when did mammals first appear?
>200MYA
evolved from synapsids
Have one opening/fenestra behind each eye
Two bones formerly within jaw joint - incorporated into mammalian middle ear
122
What are the 3 lineages of mammals?
monotremes, marsupials, eutherians
123
What are monotremes?
Small group (echidnas and platypus)
Warm-blooded & high metabolic rate
Hair over bodies
Produce milk (mammary glands but no
defined nipples)
BUT - Lay eggs
124
what are marsupials?
Include opossums, kangaroos, and koalas
Embryos develop with a placenta in mother’s uterus
Born very early in embryonic development
Complete development nursing in maternal pouch called a marsupium
125
why are eutherian mammals so diverse?
to fill numerous niches; herbivore to carnivore, terrestrial to aquatic, with some groups have even developing powered flight
126
What animals are in the primate group?
lemurs, tarsiers, monkeys, apes
127
What group are humans in?
ape group (hominoids)
128
what are 5 derived characters of primates?
A large brain and short jaws
Forward-looking eyes close together on face - depth perception
Complex social behaviour and parental care
Most primates have hands and feet adapted for grasping
A fully opposable thumb (in monkeys and apes)
129
What primates are from madagascar?
Lemurs, lorises and bush babies
130
What primates are from southeastern asia?
tarsiers
131
where did the first monkeys evolve?
old world (africa and asia)
colonised the new world (central and south america) >25MYA
132
What is the difference between old and new world monkeys?
old world: no prehensile tail, facing forward nostrils
new world: prehensile tail, side-facing nostrils
133
When did apes diverge from old world monkeys?
20-25 MYA
134
How old are homo sapiens?
about 200,000 years old
135
what characteristics distinguish humans from other apes?
Upright posture and bipedal locomotion
Larger brains
Language capabilities and symbolic thought
The manufacture and use of complex tools
Shortened jaw
Shorter digestive tract
136
when did the earliest hominin live?
about 6.5MYA
originated in africa
small brain
walked upright
137
What are the austrolaupiths?
homonins from 2-4 MYA
Paraphyletic assemblage of hominins
Some species walked fully erect
“Robust” australopiths had sturdy skulls and powerful jaws
“Gracile” australopiths were more slender and had lighter jaws
138
what are habilis?
found stone tools
139
what are homo ergaster?
First fully bipedal, large-brained hominid
Significant decrease in sexual dimorphism
140
what is the homo erectus?
first hominin to leave africa
141
what are Homo neanderthalensis?
lived in 350,000 to 28,000 years ago, initially in Europe
thick-boned with larger brain
buried their dead and made hunting tools
142
what are homo sapiens?
appeared in Africa 195,000 years ago
all living humans are descended from these African ancestors
143
what is homeostasis?
Maintenance of relatively constant internal environment
144
what is endothermy?
Body temperature depends on internal (metabolic) heat production OR active mechanisms of heat loss
145
what is ectothermy?
Body temperature depends on heat transfer to/from the environment
146
what is poikilothermy?
Body temp more or less follows ambient temp
147
what is homeothermy?
Body temp maintained constant regardless of external temperature
148
what is heterothermy?
Body temp regulated different to the environmental temperature, some times, or some body regions
149
what is an adaptation?
Biological changes over generations (i.e. genetic) due to selection of phenotypes best suited to the environmental conditions.
150
what is acclimatization?
biological changes within an animal’s lifetime associated with climatic/natural variations that influence function or tolerance (usually > 1 environmental variable, e.g. At altitude light, temperature, O2, etc all change).
151
what is acclimation?
Biological change within an animal’s lifetime simulated in the laboratory by varying a single environmental variable.
152
What does the hypothalamus do?
senses and regulates body temp. in vertebrates
153
what is vasoconstriction?
Blood shunted deeper within body (to conserve heat)
154
what is vasodilation?
closer to skin surface (to lose heat)
155
what happens in the thermal neutral zone?
Body temp regulated by blood flow to skin
156
what is piloerection?
when hairs stand erect
157
what is Thermogenesis by Shivering?
Skeletal muscles pull against each other (using ATP) --> HEAT
158
what is Non-shivering Thermogenesis?
Specialised brown adipose tissue (Brown Fat)
Abundant mitochondria Rich blood supply
159
why is it hard for water breathers to retain metabolic heat?
Gills = efficient heat exchangers
Water = conducts heat >> effectively than air
160
what is rete mirabile?
specialised red muscle in heterothermic fish line tuna
Counter current exchanger
returns heat leaving working muscle back to the muscle
161
what is an advantage of heterothermy?
Difference in muscle power of heterotherm and ectotherm is a big advantage, especially when exploiting fish prey in colder waters…
162
Q10 equation
Q10 = R2^(10/(T2-T1)
R1
163
when is thermogenesis required?
< lower critical temp
164
What kind of circulatory system do most invertebrates have? and describe it
open
arteries and veins not joined
165
what is haemolymph?
equivalent to blood
high volume but low pressure
flows around tissues
166
What kind of circulatory system do most vertebrates have? and describe it
closed
arteries and veins are joined by capillaries
blood flows within capillaries through tissues
higher pressures, low volume
167
what are the advantages of a closed circulatory system?
Rapid circulation through vessels
Selective blood distribution possible
Allows retention in vessels of:
- cellular components
- large molecules
- proteins (hormone-binding
proteins, immunoglobulins)
168
what are the disadvantages of a closed circulatory system?
higher energetic cost
169
describe a fish circulatory system
Bony fishes, rays, and sharks
single circulation
two-chambered heart (1 Atrium, 1 Ventricle)
Blood leaving heart passes through two capillary beds (gills & systemic) before returning
170
describe an amphibian circulatory system
3-chambers (2 Atria, 1 Ventricle)
Ventricle anatomy diverts most deoxy-blood to lung/skin, and most oxy-blood to systemic circuit
171
describe a reptilian amphibian circulatory system
3-chambers (2 Atria, 1 Ventricle)
“Pulmonary” blood shunted to systemic circuit by arterial valves when under-water.
(Complete septum in crocodilians)
172
describe a mammal and bird circulatory system
4-chambered heart (2 Atria, 2 Ventricles)
Complete separation of Pulmonary & Systemic circuits
Allows higher flow rates and pressures in both circuits
Key adaptation in endotherms (10 x greater energy turnover cf. Ectotherms)
173
what does the right side of a human heart do?
Pumps deoxygenated blood to lungs (pulmonary circuit)
174
what does the left side of a human heart do?
Pumps oxygenated blood to rest of body (systemic circuit)
175
What is a cardiac muscle (myocardium) unique feature?
All have electrical continuity (Gap Junctions) – allows coordinated contraction
176
what are the 3 types of fibre in the heart?
1) Sinoarterial (SA) node & atrioventricular (AV) node
(Small, weakly contractile, autorhythmic)
2) Inner Ventricle Wall
(Largest, weakly contractile but fast conduction)
3) Bulk of heart
(Medium, strongly contractile)
177
what does myogenic mean?
generated within heart muscle itself (myocardium)
178
what is the rhythm of the heart due to?
Pacemaker cells
= origin of Action Potential (AP) in
all myocardial cells (Autorhythmic)
179
what is systole?
contraction phase
180
what is diastole?
relaxation phase
181
where are the pacemaker cells?
in SA Node
182
are cardiac APs long or short lasting?
long
~300 ms
Due to Ca2+ channels remaining open (longer to re-polarise
183
what is the heart beat cycle in vertebrates?
1) SA Node (Pacemaker cells) – AP starts
2) AP Spreads – through Atria (electrically coupled cells) –
-->CONTRACTION
3) AV Node – starts new (delayed) AP - spreads rapidly throughout Ventricles via:
bundles of his and purkinje fibres
184
What does Adrenaline/Noradrenaline do?
Sympathetic input
SPEEDS UP
185
what does Acetylcholine do?
Parasympathetic input
SLOWS DOWN
186
what do neurotransmitters do?
influence the resting potentials of the pacemaker cells, speeding up or slowing the heart rate
187
what is the cardiac output equation?
cardiac output = heart rate x stroke volume
(L/min) (beats/min) (L ejected/beat)
188
Air Flow Rate x (Insp. – Exp.) [O2 ]
( L / min ) ( mmol O2 / L )
=
Cardiac Output x (Art. - Ven.) [O2 ]
( L / min ) ( mmol O2 / L )
189
what is the structure of a blood vessel from out to in?
connective tissue
smooth muscle
endothelium
(capillary - just basal lamina then endothelium)
190
what are the key differences between arteries and veins?
1 - Arteries are thicker and more elastic (higher blood pressure)
2 – Veins have valves (for unidirectional blood flow)
191
what is the equation for mean arterial blood pressure?
Mean Arterial Blood Pressure (MABP)
= Diastolic BP + (⅓ Pulse Pressure)
192
what is the equation for pulse pressure?
Pulse Pressure
(= Systolic BP – Diastolic BP)
193
what is bradycardia?
decreased heart rate
194
what is tachycardia?
increased heart rate
195
what happens in diving mammals?
temporary slowing of metabolism in selected tissues
anearobic (glycolytic) respiration.
196
how are diving mammals different to terrestrial mammals?
they have MUCH bigger:
Blood Volume
Haemoglobin concentration
Myoglobin content in tissues
(extra O2 carrying pigment)
carry much more O2 stored within body
197
what are the 5 requirements for gas exchange surfaces?
1. permeable to gases
2. moist
3. thin
4. large SA:V
5. convection (larger animals)
198
what are evaginations?
'external' gills
199
what is the pleural cavity?
lungs
200
what is the peritoneal cavity?
gut and other organs
201
what is the pericardial cavity?
heart
202
why do we need convection?
1. stirs boundary layers
2. moves molecules faster than diffusion over long distances
203
Describe Haemoglobin
in vertebrates
red
contains Fe2+
cellular
204
describe haemocyanin
in arthropods and molluscs
blue
contains Cu2+
free solution
205
what do pigments do in blood?
increase capacity for O2 in blood
206
how is gas exchange achieved?
1. simple diffusion
2. convection of internal medium only
3. convection of external medium only
4. convection of internal and external media
207
how is a unidirectional flow of water acheived?
active double pump system
ram ventilation
208
what is ram ventilation?
relax muscles
use energy already spent on locomotion to drive water past gills
209
describe the structure of the gills
operculum - protective covering
arches - 4 each side, cartilage, carry major blood vessels
filaments - 2 rows on each arch
lamellae - 2 rows on each filament, thin
210
what are the units for partial pressure?
mmHg
kPa
211
what are the units for gas content?
ml O2 / L
mg O2 / L
mmol O2 / L
212
what is the equation for O2 extraction efficiency %?
(inspired [O2] - expired [O2])
--------------------------------------------- x 100
inspired [O2]
213
what are the advantages of coulter current O2 extraction?
1. more efficient removal of O2 from water
2. higher % blood O2 saturation possible
214
Is O2 and CO2 content higher in water or in air?
O2 higher in air than water
CO2 solubility higher is water than O2
215
what are the units for flow rate of water /blood?
ml / min
ml.min-1
216
describe the mammal lung structure
trachea
bronchi
bronchioles
respiratory bronchioles
alveoli (= respiratory units)
217
how many alveoli per lung?
150 million
218
what are the 2 anatomical adaptations of bird lungs?
1. unidirectional flow created by air sacs
2. parabronchi
219
What are 2 important features of mammalian lungs?
1. mucus escalator - mucus traps debris and bacteria, cilia produce upwards movement
2. surfactant - reduces surface tension in alveolar fluid layer
220
when are the intercostal muscles used?
only during forced exhale
221
what does a low turnover mean in terms of tidal ventilation?
1. smaller changes in alveolar O2 and CO2
2. lower average alveolar O2 content
3. low extraction efficiency
222
which receptors control breathing?
in medulla:
peripheral O2 receptors (aorta and carotid arteries) can modify breathing
CO2 sensors in medulla are most important for feedback and control of breathing
223
what are the consequences of tidal ventilation?
tidal volume is small
low turnover of lung air per breath
224
what is osmoregulation?
control of salts and water balance in internal fluids
225
what are solutes?
anything dissolved in the solvent
226
what are electrolytes?
ionised solutes
227
what is salinity?
total salt concentration
228
what is osmotic conc?
osmolarity
229
what is an osmolyte?
anything exerting an osmotic pressure
230
what is a hypo-osmotic solution?
more dilute outside
- swelling, lysis
231
what is a iso-osmotic solution?
same inside and out
- influx = efflux
232
what is a hyper-osmotic solution?
more con outside
- shrinkage
233
what is an osmoconformer?
body fluid osmolality similar to external environment
234
what is an osmoregulater?
maintain body fluids different to external osmolality
235
does a hypo-osmotic regulator have body fluid osmoality < or > external?
body fluid osmoality < external
236
does a hyper-osmotic regulator have body fluid osmoality < or > external?
body fluid osmoality > external
237
what does stenohaline mean?
narrow salinity range
just freshwater or just sea water
238
what does euryhaline mean?
wide salinity range
from fresh to sea water or higher
239
are most marine invertebrates osmoconformers or osmoregulators?
osmoconformers
240
are all fresh water animals hyper or hypo-osmoregulators?
hyper-osmoregulators
241
what are the main 3 osmotic strategies?
1. osmoconform + ionoconform
(hagfish)
2. osmoconform but ionoregulate
(elasmobrachs and coelacanths)
3. osmoregulate and ionoregulate
(teleosts and lamprey
242
what do ATPases do?
used to create diffusion gradient that secondarily drives facilitated diffusion
243
what is membrane potential?
voltage difference across a membrane
- created by differences in the distribution of positive and negative ions
244
what is an electrochemical gradient?
the combo of 2 forces which drive the diffusion of ions across a membrane
245
what is an electrogenic pump?
membrane protein that generates electrical potential across a membrane due to the resulting ion transport
246
what are tight junctions?
barrier that limits transepithelial diffusion of molecules between adjacent cells
247
what are the purpose of tight junctions?
1. joins neighbouring cells together
2. barrier between apical and basolateral membranes
248
what are the 3 major nitrogen-excretory products?
1. ammonia - (ammonotelic)
2. urea - (ureotelic)
3. uric acid - (ureotelic)
249
which animals are ammonotelic?
all teleost fish, lampreys and hagfish
all aquatic invertebrates
250
how is urea produced?
ornithine-urea cycle
- most vertebrates except teleost fish
251
what is communication?
process by which
signals transmitted to one or more
receivers, controlling/coordinating actions
252
How does the endocrine system work?
Hormones synthesized by endocrine cells
in response to internal/environmental
stimuli
* Released into bloodstream to target cells
where trigger response by binding specific
receptors
* Signal transduction within cells brings
about physiological response
* Feedback control loops enable tight
homeostatic control
253
what are the 4 types of chemical signalling in the endocrine system?
Autocrine signalling
Paracrine signalling
Endocrine signalling
Neuroendocrine signalling
254
what is the type of signalling in the nervous system?
synaptic signalling
255
How does synaptic signalling work?
neurotransmitters diffuse short distances
trigger responses in interconnected cells
256
how does endocrine signalling work?
secrete molecules into the bloodstream
trigger responses anywhere in body
257
describe peptide hormones
often produced as larger precursors
water soluble (hydrophilic, lipophobic)
comprise the largest number of hormones, e.g. insulin
258
describe amine hormones
Derived from amino-acid precursors
either water soluble (e.g. adrenaline, noradrenaline)
or water insoluble (thyroid hormone)
259
describe steroid hormones
Synthesised from cholesterol, primarily in the adrenals and gonads
Water insoluble (lipophilic or hydrophobic)
e.g. estrogens, androgen, cortisol
260
describe fatty acid derivatives (Eicosanoids)
derived from polyunsaturated fatty acids (e.g. arachidonic acid)
Water insoluble (lipophilic)
e.g. prostaglandins
261
how are the hormones secreted depending on water solubility?
water soluble - secreted by exocytosis, transported freely in blood
water insoluble - require special transport proteins
262
describe the response for water soluble hormones
Hormone binding to receptor initiates signal transduction pathway, leading to response in cytoplasm.
e.g. enzyme activation, cytoskeleton movements, membrane transport
activation, altered gene expression – (less common)
263
What does adrenaline binding cause?
G protein activation (binds GTP)
activates adenylyl cyclase enzyme
catalyses conversion of ATP to cyclic AMP (cAMP)
cAMP = rapid rise e.g. 20x in secs, short lived
264
what does cAMP cause?
activation of protein kinase A
enzyme activation/inactivation
265
what does protein kinase A do?
inhibition of glycogen synthesis
promotion of glycogen breakdown
266
describe the response of lipid soluble hormones
Steroids, thyroid hormones, and hormonal form of vitamin D enter target cells, bind to protein receptors in cytoplasm or nucleus
Protein-receptor complexes act as transcription factors in nucleus regulating
transcription of specific genes
267
what does insulin do to blood glucose levels?
decreases them
produced by pancreatic beta cells
268
what does glucagon do to blood glucose levels?
increases them
produced by pancreatic alpha cells
269
what is type 1 diabetes?
insulin-dependent
autoimmune disorder in which the immune system destroys pancreatic beta cells
270
what is type 2 diabetes?
non-insulin-dependent
insulin resistance: deficiency or reduced response of target cells due to change in insulin receptor
271
what does the hypothalamus do?
Hypothalamus sends signals to the pituitary chemically (anterior pituitary AP) or through
neurosecretory cells (posterior pituitary PP)
Hypothalamus receives nervous stimuli from receptors throughout the body monitoring chemical and physical
status e.g. temperature; blood pressure; nutrients, hormonal status
272
what does the posterior pituitary hormones do?
2 hormones act directly on non-endocrine tissues
Oxytocin regulates milk secretion in mammary glands
Antidiuretic hormone (ADH) regulates kidney physiology and behaviour e.g. thirst
273
which animals dont have a type of nervous system?
sponges
274
why are cephalopod giant axon useful?
first quantitative model of the electrical excitability of neurons was described for giant axons
275
what do sensory neurones do?
detect external stimuli and internal conditions.
276
describe neurone structure?
Dendrites: highly branched extensions that receive signals from other neurons
Axon: longer extension, covered with myelin sheath, transmits signals to other cells at synapses
277
what are glia?
supporting cells, essential for structural
integrity and normal functioning of neurons
278
what are the glia that form myelin sheaths around axons of many vertebrate neurons called?
Oligodendrocytes (CNS) and Schwann cells (PNS)
279
what is the resting potential?
Membrane potential of a neuron that is not transmitting signals
- 50mV
280
what does resting potential depend on?
ionic gradients
281
what is electrochemical equilibrium?
When chemical gradient and electrical gradient are equal
282
what is an electrical synapse?
electrical current flows directly from one cell to another via gap junction
283
what is a chemical synapse?
presynaptic neuron releases chemical
neurotransmitters, which are stored in synaptic terminal
