Explain how the structures of the phloem and cardiac muscle are related to their functions

In this question, examine the structure of particular parts of the tissue and relate this to the function.

Phloem

• The sieve tube cells are elongated, tubular and placed end to end to from a continuous channel for continuous flow of of materials.
• Cavies of the sieve tubes are large to aid mass flow of materials.
• The sieve plates are performed by numerous pores to allow the passage of materials from one sieve element to the next.
• Cytoplasmic strands facilitate translocation by cytoplasmic streaming
• The sieve tube cells have no nuclei hence avail more space for translocation.
• The companion cells are highly metabolic to sustain needs of the sieve tube.
• Phloem parenchyma aids in the storage of food and in controlling slow conduction.
• Phloem fibers provide mechanical support and rigidity to plant organs.

Cardiac muscle.

• Numerous mitochondria to provide energy for contraction
• SAN specialized cardiac muscle for myogenic activity
• The intercalated discs allow fast transmission of impulse from one fiber to the another by allowing rapid passaged of ions. This allows spread of an impulse through the muscle.
• The numerous blood capillaries quickly deliver oxygen and nutrients to the muscles and remove wastes to allow the muscles to contract without fatigue.
• The fibres contain action and myosin which contract.
• The fibres branch and cross-connect with each other allowing the entire heart to behave as a unit.