Support and movement Flashcards
What structure features of plants help support them?
Turgor pressure
Shoot and root systems
Pith/ cortex relationship
Vascular bundles
What is the pith made up of?
Parenchyma
Thin cell walls
Able to expand in response to increasing fluid in vacuole
Can exert pressure on tissue around them
What is the cortex made up of?
Collenchyma
Have primary wall with some thickening
Provides support and offers flexibility for plant to move in the wind
Why are vascular bundles surrounded by sclerenchyma?
Sclerenchyma have a thick secondary cell wall so they can bend and recoil (elasticity)
Allows plant to stretch and bend
What is the purpose of lateral roots?
Primarily absorption of water and dissolved minerals
And some support provided
What is the purpose of the primary root/ tap root?
Anchorage and stability
What are three types of skeletal systems used by animals?
Hydrostatic skeleton
Exoskeleton
Endoskeleton
Describe a hydrostatic skeleton.
Capsule of fluid surrounded by two layers of muscle: circular and longitudinal
Fluid filled cavity acts as a rigid column on which muscles act
What is an example of an organism with a hydrostatic skeleton?
Earthworm
How does a hydrostatic skeleton help an animal to move?
Circular muscles contract: elongating and narrowing the body
Longitudinal muscles contract: shorten and thicken the body
Segmental contraction of muscles and anchorage by bristles drives the body forwards: burrowing
What are some organisms that use an exoskeleton?
Mollusks: clams and mussels
Arthropods: insects and crabs
Describe an exoskeleton.
Hard outer surface that provides protection of soft tissues like armour
Made of chitin arranged in many layers
What are some benefits of an exoskeleton made of chitin?
Strong and light
Can be mineralised to become harder
Thin and flexible at joints
What are some issues with the use of an exoskeleton?
Can be crushed
Does not grow in line with body: must molt the exoskeleton (ecdysis)
Potential vulnerability until it hardens
What are the two types of endoskeleton?
Cartilaginous
Bony
Why can’t ants get reallyyyy big?
It would need to develop a significantly stronger and thicker skeleton to support an increased mass, if the exoskeleton became thicker and stronger it would be too heavy for the ant to move with
Sad times, ant must stay as small boi
What is the benefit of an endoskeleton made of cartilage?
Buoyant
Efficient
Flexible
Issues with an endoskeleton made of cartilage?
Cartilage is avascular so the skeleton must remain thin to allow diffusion of nutrients from surrounding tissues
These thin skeletons can’t support the fish outside of water
Sad times, fishy must stay as wet boi
What are the benefits of a bony endoskeleton?
Rigid support against gravity
Supports weight of large animals on land
Dynamic: responds to physiological loading
What does a bony endoskeleton develop from?
A cartilaginous skeleton
What is in the central cavity of bones?
Yellow marrow
What is the benefit of bones not being solid?
Reduces weight
Strength: helps resist compression and tension
Is skeletal muscle striated or non-striated?
Striated
Is skeletal muscle voluntary or involuntary?
Voluntary
Three primary functions of skeletal muscle?
Movement
Posture
Heat production
What is a muscle belly?
Central fleshy part of a muscle
What are the two main components of a muscle?
Contractile cells
Connective tissues
What is the functional unit of a muscle?
The muscle cell/ muscle fibre
Long multinucleate cells formed by a collection of microfibrils, which are formed from the myofilaments actin and myosin
What is the benefit of fibres in muscles being arranged in parallel?
Wide range of movement
What is the drawback of fibres in muscles being arranged in parallel?
Not particularly strong
What is the benefit to muscle fibres being arranged at an angle?
Stronger force of contraction
What is the drawback to muscle fibres being arranged at an angle?
Limited range of movement
What is the function of tendons?
Transfer the force of a muscle to bone
Describe the structure of tendons.
Made of mostly type 1 collagen Two specialised regions: myotendinous junction (where tendon attached to muscle) osteotendinous junction (where tendon attached to bone)
What does isotonic contraction mean and what are the two types of isotonic contraction?
Constant tension: tension in the muscle causes changes in the length of the muscle
Concentric and eccentric (Poh)
What happens in a concentric muscle contraction?
Muscle gets shorter when it contracts
What happens in an eccentric muscle contraction?
Muscle lengthens
What is an isometric contraction?
Muscle stays roughly the same length during contraction
