Arthropods Flashcards
what is the most diverse eukaryotic group?
Anthropods
Dysticus is a
predaceous diving beetle
how do Dytisucs breathe?
adults collect air under wings and use this to breathe underwater
What is the structure of an Arthropod?
- Reduced segmentation
- body regions
- jointed appendages
What kind of skeleton do Arthropods have?
rigid exoskeleton
Arthropods are …
ecdyosozon (which means they are moulting animals)
what does the rigid exoskeleton of a Arthropod cover?
all external surfaces, digestive tract and the tracheae
What are the advantages of having a rigid exoskeleton?
Physical support
What are the advantages of having a rigid exoskeleton?
place for muscle attachment
What are the advantages of having a rigid exoskeleton?
physical protection from abrasion, predatation, parasite entry and desiccation
What are the advantages of having a rigid exoskeleton?
Location of pigments - camouflage
What are the advantages of having a rigid exoskeleton?
jointed appendages and exoskeleton allow faster locomotion
What are the advantages of having a rigid exoskeleton?
Opportunity to change morphology between larval and adult stages
Why is it important to change between life stages?
Less competition within the species
What the disadvantages of having a rigid exoskeleton
Infelixble and heavy
What the disadvantages of having a rigid exoskeleton
continuous growth in size is not possible
What the disadvantages of having a rigid exoskeleton
requires energy to form and shed
What the disadvantages of having a rigid exoskeleton
prevents the use of cilia as effectors
What the disadvantages of having a rigid exoskeleton
respiration through the skin is not possible
How do arthropods breathe?
through spiracles - pores and tracheae - tubes
what needs to be removed before myosin can bind?
tropomyosin
what spikes drive muscle contractions?
motor neurons
what causes the contraction of the sarcomere?
sliding of thick filaments between thin filaments
Name the 3 types of skeletons
- hydrostatic skeleton
- exoskeleton
- endoskeleton
what do skeletal muscles need?
a resistor to act against
what is a skeleton?
points of attachment for the muscles
skeletal muscles are often found in…
antagonistic piars
in which direction do skeletal muscles act?
they act in opposite directions
Organ
muscle tissue and connective tusse
multinucleate cell that contains many myofibrils is called a
muscle fibre
myofibrils are
composed of protein bundles
contractile unit of a myofibril
sacromeres
where do the muscle fibre commands come from?
the spinal cord
Neuromusclar junction is when the
motor neuron creates a synapse with the muscle fibre
what is the characteristic of a Neuron at rest?
higher concentrations of Na+ outside of a neuron and higher concentrations of K+ on the inside
a single spike in a motor neuron can cause a …
single excitatory postsynaptic potential (EPSP) and spike in the associated muscle fibers, followed by a single twitch
what is needed for actin and myosin to separate?
ATP
Motor Unit
neuron + muscle fiber
for vertebrate skeletal muscle, each muscle fiber is innervated by what?
a single motor neuron, but each motor neruon innervates many muscle fibers
How does an entire muscle contract?
single action potential generates a single twitch
what does the force generated by entire muscle depend on?
- number of motor units (aka motor neuron and associated muscle fibers) activiated
- frequency at which motor untis are firing
Characteristics of skeletal muscles
Striated
Characteristics of skeletal muscles
Cylindrical
Characteristics of skeletal muscles
Multinucleated
Characteristics of skeletal muscles
Most are under voluntary control
Characteristics of skeletal muscles
Actions where skeletal muscles are involved: running, standing, shivering
Characteristics of cardiac muscles
Striated
Characteristics of cardiac muscles
branched in shape which allow them to withstand high pressures
Characteristics of cardiac muscles
Smaller than skeletal muscle cells; have only one nucleus
Characteristics of cardiac muscles
gap junctions between cells allow synchronized contraction
Characteristics of cardiac muscles
forms a mesh nest around the hollowness - prevents gaps due to pressure
Characteristics of a smooth muscle
Actin and myosin are not as regularly arranged - not striated
many skeletal muscles are paired for
antogonistic action
skeletal muscles are composed of proteins that don’t _____ but instead ____ past one another
contract ; slide
