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Flashcards in Animal physiology 2 Deck (25):
1

Muscle fibres contain bundles called ______

myofibrils

2

What are actin filaments?

Twisted chains of monomers (like a string of beads)

3

What are myosin filaments?

ordered bundles of tadpole-like molecules
each has head and coiled tail

4

What are sarcomeres?

repeated units along myofibrils

5

What borders adjacent sarcomeres?

Z-lines

6

How do you take muscle to bits?

Skinning - cold glycerol or triton X removes cell and other lipid membranes
Conc. salt solution with no Ca++, actin and myosin separate

7

What are myofibrils?

Formed when actin and myosin overlap

8

Who has evidence for the sliding filament theory and what is it?

Gordon, Huxley and Julian

Measured force at different sarcomere lengths, stretch to chosen length then activate electrically, measure force then repeat at different lengths

9

Force in one sarcomere is proportional to

The number of cross bridges

10

What are some characteristics of fast twitch muscle fibres?

glycolytic
pale
few mitochondria or blood vessels or myoglobin

11

What are some characteristics of slow twitch muscle fibres?

oxidative
dark
many mitochondria and myoglobin

12

Which insects have synchronous flight muscles? (1 spike per twitch)

dragonflies/damselflies
locusts
moths

13

Which insects have asynchronous flight muscles? (high wingbeat frequency)

flies
beetles
bees
wasps

14

What is a motor unit?

Motor neuron plus muscle fibres

15

How can force be regulated?

Number of motor units that are active

16

What are tonic fibres?

Muscle in vertebrates that receive multi-terminal innervation from a single motor neuron axon
They are inexciteable

17

What is vertebrate twitch muscle fibre?

muscle fibre spikes when PSP generated at a synapse

18

Does insect muscle fibre spike?

no

19

What are the 2 components of respiration?

Internal cellular respiration
External respiration

20

What are the definitions of:
Anoxia
Hypoxia
Normoxia
Hyperoxia

No oxygen
Low oxygen
Normal oxygen
High oxygen

21

Why is diffusion insufficient?

Animal phyla have increased in size
Diffusion distances no longer very small

22

How is diffusion augmented?

Enhancement
Bulk transport

23

What are diffusion enhancements?

High permeability
Thin epithelia
Large SA
Vascularisation
Gas can be converted into non-diffusible form

24

What are the two main types of bulk transport?

Ventilation
Circulation

25

How does a sea cucumber breathe?

Respiratory trees, tidal ventilation