Unit 5: Growth & Post-Embryonic Develop Flashcards
(23 cards)
What is hypertrophy in the context of growth?
An increase in individual cell size
What is accretion?
Growth through extracellular matrix (ECM) secretion
What are cyclins and what is their role?
Cyclins are proteins that regulate checkpoints in the cell cycle
Define morphallaxis
A type of regeneration where existing cells rearrange without undergoing mitosis
Define epimorphosis
A type of regeneration involving dedifferentiation and subsequent cell division
What is a blastema and what does it do?
A mass of regenerative tissue formed after injury, responsible for producing new cells
What is the function of the apical cap in regeneration?
It forms over the amputation site and is essential for initiating regeneration
What are the main components of post-embryonic development?
Growth, metamorphosis, and regeneration
What is the primary focus of embryonic development?
Establishing the organism’s body plan
What is proliferation in biological growth?
The increase in cell number through mitosis
What is an example of hypertrophy in tissues?
Growth in the heart or nerves due to enlarged cell size
Which tissues grow through accretion? proliferation?
Bone and cartilage
Gut lining
How are cyclins linked to cancer development?
Disruption of cyclin regulation can lead to uncontrolled cell growth, such as in pancreatic cancer
Why do most cancers arise in epithelial tissues?
Because stem cells in these tissues divide frequently, increasing the chance of mutations
What is the role of tissue stem cells in cancer initiation?
Mutations in dividing stem cells can lead to tumor formation and uncontrolled growth
Which hormone regulates amphibian metamorphosis?
Thyroid hormone
Which hormone regulates amphibian metamorphosis? What effect does it have during amphibian metamorphosis?
Thyroid
It promotes limb growth and suppresses tail growth
What are the two main types of regeneration, and how do they differ?
- Morphallaxis: rearrangement of existing cells without division (e.g. hydra)
- Epimorphosis: regeneration involving cell division after dedifferentiation (e.g. salamanders)
What regenerative abilities do lower vertebrates have?
They can regenerate limbs, heart tissue, and even parts of the brain
What tissues can regenerate in mammals?
Skin, blood, and liver
steps of amphibian limb regeneration
- Amputation
- Formation of apical cap
- Epidermal wound coverage
- Blastema formation
- Dedifferentiation of muscle cells
- Macrophage involvement in tissue regeneration
What role do macrophages play in amphibian limb regeneration?
They are essential for initiating and sustaining the regeneration process
What was revealed about blastema cells from GFP lineage tracing experiments?
Most blastema cells are lineage-restricted rather than truly multipotent
