7. Animal Tissue, Reproduction And Development Flashcards
(106 cards)
What is a fusiform shape?
A spindle-like shape that tapers at both ends.
The body shape of the fur seal is fusiform. Skeletal muscle cells are fusiform.
Diversity in animal anatomy is due to…?
- Natural selection.
- Adaption.
- Sexual reproduction ensuring mixing of DNA.
What is divergent evolution?
A common ancestor over time gives rise to different species with distinct features.
What is convergent evolution?
Different species independently evolve similar features due to having a similar environment.
What are homologue structures?
Structures that share a similar common ancestor despite potentially serving different functions in different species.
What are analogue structures?
Structures that serve a similar function but do not share a common evolutionary origin.
Why can hydras perform gas exchange directly?
They are only two cells thick, with each cell in direct contact with its environment.
Why can’t many multicellular organisms diffuse with their environment?
Many multicellular organisms have complex internal structure and a low surface area to volume ratio (SA:V ratio).
How do multicellular organisms increase surface area for gas exchange?
The cells in multicellular organisms have evolved to have folded or branched surfaces located in a protected and moist environment.
What hydrates the space between cells?
Interstitial fluid.
What are the 4 main types of animal tissues?
- Epithelial tissue.
- Connective tissue.
- Muscular tissue.
- Nervous tissue.
What are epithelial tissues?
Tightly packed cells that line organs, body cavities, and external surfaces.
E.g. skin.
What are connective tissues?
Tissues that bind and support other tissues with a sparse population of cells scattered through an extracellular matrix.
E.g. cartilage of the knee.
What are muscular tissues?
Tissues comprised of long cells that can contract on their own or when stimulated by nerve impulses.
E.g. biceps muscle.
What are nervous tissues?
Tissues comprised of neurons and support cells.
What are the 3 shapes of epithelial cells?
- Squamous.
- Cuboidal.
- Columnar.
What are squamous cells?
Egg-shaped, thin cells with a flattened centrally located nuclei parallel to the cell surface.
Involved in diffusion - well suited to fluid and gas exchange.
What are cuboidal cells?
Cells that are approximately equal in height, length, and width, with nuclei that are normally spherical and centrally located.
Involved in secretion or protection.
What are columnar cells?
Tall column shaped cells with an ovoid basallly located nucleus.
Involved in absorption and secretion - well suited to protecting the underlying tissue.
What type of columnar cells are involved in absorption?
Simple columnar epithelial cells.
What type of columnar cells are involved in secretion?
Goblet cells.
What is simple epithelium?
A single layer of closely packed epithelial cells that form a lining on various surfaces and cavities in the body.
What is stratified epithelium?
Multiple layers of epithelial cells, with only the bottom layer touching the basement membrane.
The apical surface often faces the lumen.
What is the lumen?
The internal cavity of a tubular structure.
Mainly used to transport gases, fluids, nutrients, and waste around the body.
E.g. the lumen of the aorta, the lumen of the intestines, or the lumen of the arteries.