Overview + Neuron System Function Flashcards
Taxonomy
the classification of organisms
Phylum
Grouped organisms of common descent that share a fundamental pattern of organization
Level Of Organization In Biological Systems
- Cells are organized into tissues.
- Tissues are organized into organs.
- Organs are organized into systems.
- Systems form an organism (usually)
Protoplasmic
- Found in unicellular organisms.
- Life functions are confined to a single cell.
- Contains organelles with specific functions.
Cellular
- Cell aggregations with different functions.
- Division of labor, nutrition, reproduction
Tissue
- Similar cells are found in layers
- contains organelles with specific functions
- eg. nerve net
Organ
- More than one tissue type working together to have a more specialized function.
- Flatworms
- eg. heart / eyespots / reproductive system
System
- Organs work together to perform some function
- Organ systems
- eg. circulation, respiration
- Most animal phyla
Asymmetry
No division can create identical halves
Bilateral Symmetry
Division along the sagittal plane creates a mirror image
Spherical Symmetry
Division through any center creates mirrored halves; rare in animals; unicellular
Radial Symmetry
Division through longitudinal planes creates mirrored halves; free-floating or slow swimming; animal has “top” and “bottom”
cephalization
- the differentiation of a head
- Bilateral symmetry is associated
Cavity 1: The gut
Blastopore: site of first hole/indentation
* Medusa has only 1 hole to ingest food and expel waste
* Blind or incomplete gut
* A second opening creates a tube for food and waste to enter and exit, respectively.
* One-way or complete gut
* Food enters and exits in 1 direction
Cavity 2:
Coelom: Greek – Hollow, cavity
Groupings according to presence or type of body cavity, the coelom
Coelom
- fluid-filled cavity between gut and body wall that is lined with mesodermal cells
- major innovation in bilaterally symmetric animals
- Tube within a tube arrangement
Coelomate advantages
- Flexibility for crawling and burrowing
- Independent growth of organs from the body wall
- Cushioning
- Skeletal function
- Circulation of nutrients and wastes
What Is A Tissue?
A cooperative unit of many very similar cells that perform a specific function.
* Epithelial
* Connective
* Muscle
* Nervous
Epithelial Tissue
Covers and lines the body and its parts
* One surface free, the other bound to basement membrane (ECM)
* Tissues are named by
– Number of layers of cells
(Simple or stratified)
– Shape of cells (Squamous, cuboidal, or columnar)
Connective tissue
1) Connective tissue proper (true fibers): loose and dense
2) Cells based in a fluid: blood, lymph and interstitial fluid
3) Bone and cartilage
Muscle Tissue
Skeletal, cardiac, smooth, and mesoderm derived
Neural Tissue
Responsible for coordinating body activities
* Neurons are nerve cells
* Composed of cell body and dendrites
* Supported by glial cells (non-neuronal) e.g. Schwann cells
