Muscles and Animal Movement Flashcards
What organisms have muscles?
All phyla above porifera
By what is muscle performance governed?
Speed of response and efficiency in in converting chemical energy to mechanical energy.
What are the three types of of vertebrate muscle tissue?
Skeletal, cardiac and smooth
What does muscle tissue contain?
Cells for contraction and force generation.
what is the highest frequency of vertebrate locomotor muscles?
25-30Hz
How much of the human is muscle?
Around 50%
How much of the human body is skeletal muscle for males and females respectively?
40% and 32%
What percentage of fish total bodyweight is muscle?
Around 20-50% normally but 55-65% for Barracudas.
How is skeletal muscle categorised?
Striated and voluntary.
How is cardiac muscle categorised?
Striated and involuntary.
How is smooth muscle categorised?
Unstriated and involuntary.
How big are skeletal muscle cells?
10-100 um in diameter and 75 cm in length.
Why do skeletal muscle cells have multiple nuclei?
From the fusing of myoblasts in development.
What are myofibrils?
Specialised contractile elements that extend the entire length of the muscle fibre.
What do myofibrils consist of?
Thick and thin filaments
Of what are thick filaments made?
Assemblies of myosin
Of what are thin filaments comprised?
Actin
What are sarcomeres?
The smallest part of the muscle that can contract.
Of what do sarcomeres consist?
One A band and two I bands.
What are muscles?
Groups of muscle fibres bundled by connective tissue often attached to skeletal elements in antagonistic pairs.
What are tendons?
Areas of vertebrate muscle that have extended beyond the muscle.
What do muscles attach to in arthropods?
Apodemes
What is a muscle twitch?
A brief, weak contraction of a single muscle fibre.
What are the two primary factors that are adjusted to accomplish gradation?
The number of muscles contracting and the tension developed by each contracting fibre.
What is the number of fibres contracting in vertebrates dependent on?
The extent of motor unit recruitment.
What is each muscle innervated by?
A number of different motor neurons.
When do vertebrate motor neurons branch?
As they enter the muscle with each axon terminal supplying a single muscle fibre.
How many motor neurons are arthropod muscles innervated by?
More than one.
What is used in submaximal contractions to prevent fatigue?
Asynchronous recruitment of motor fibres.
What determines the number of muscle fibres contracting?
The number of motor units, the number of muscle fibres per motor unit and the number of fibres available to contract.
What determines the tension developed by each contracting fibre?
- The frequency of stimulation
- The length of the fibre at the onset of contraction
- The extent of fatigue
- The duration of activity
- The type of fibre
- The thickness of the fibre
- The pattern of neural activity
- The amount of testosterone
What are the roles of skeleton?
Structural support, protection and facilitation of movement.
What are the three types of eukaryotic cytoskeletal filaments?
Microfilaments, intermediate filaments and microtubules.
What do fibroblasts secrete?
Collagen in skin cells
What do chondrocytes secrete?
A matrix of cartilage
What is the function of osteoblasts and osteoclasts?
To model bone
What is the structure of prokaryotic flagellum?
They consist of the filament flagellum and have a hook and basal body responsible for motion.
How do spirochetes move?
The whole cell moves with a corkscrew motion.
How do cyanobacteria adjust their buoyancy?
By adjusting the amount of gas in their gas ventricles.
What are the three modes of locomotion in protists?
Amoeboid movement, swimming by means of cilia, swimming by means of flagella.
How do ctenophores move?
They have eight rows of cilia bearing plates called ctenes that they use to swim.
How do acoelomate planarians move?
They use beating cilia.
What are the three skeletal systems in animals?
Hydrostatic, exoskeletal and endoskeletal
What constrains the pseudocoelomate body?
A flexible but inelastic chitinous cuticle which resists change in volume.
What causes the pseudocoelomate body to ben back and forth?
Contraction of longitudinal muscles against high hydrostatic pressure.
How do coelomate worms move?
By extending and shortening sections of the body.
What facilitates coelomate movement?
Circular and longitudinal muscle layers and segmental compartments.
Of what is the arthropod cuticle comprised?
A layer of proteins and chitin - a strong waterproof polysaccharide.
What does the arthropod cuticle act as?
A protective exoskeleton.
What are the limitations of the arthropod exoskeleton?
It limits growth and demands new mechanisms of gaseous exchange and locomotion.
What are muscles attached to in endoskeleton systems?
To the inside of the exoskeleton.
What did the evolution of the endoskeleton allow?
The potential for locomotion.
What are the four key features of vertebrates?
- A rigid internal skeleton supported by a vertebral column.
- An anterior skull with a large brain
- Internal organs suspended in coelom
- A well developed circulatory system driven by contractions of a ventral heart
What is chitin comprised of?
N-acetylglucosamine
