Animal architecture and Unicellular eukaryotes Flashcards
Protoplasmic level of organization
- All life functions within a cell
- Differentiated organelles that perform specific functions
Cellular level of organization
- Aggregation of cells exhibiting functional differentiation
- Division of labor between cells (eg., reproduction, nutrition)
- CELLS NOT ORGANIZED INTO TISSUES
Cell-tissue level of organization
-Aggregation of cells into tissues
- tissues are defined by patterns and layers
Tissue-organ level of organization
-Aggregation of tissues into organs
- Organs are made up of more than one kind of tissue (parenchyma and stroma)
parenchyma
cells that carry out main function of the organ (ie., secreting cells of pancreas: insulin)
stroma
cells/ connective tissue that support organ structure (ie., capsuled pancreas: provide structural support for pancreas)
Which organs work together to constitute the digestive system?
- Gastrointestinal tract (oral cavity, esophagus, intestine, pharynx, stomach)
- Accessory digestive organs ( salivary glands, gallbladder, liver, pancreas)
- both carry out nutrition in the body
Tissue
- An organization of like cells
- The fundamental structure of which animal organs are composed
Epithelial tissue
- Sheet of cells that cover an external or internal surface
- Different types exist
Connective tissue
Diverse group of tissues, specialized to bind and support other tissues
- collagen is main protein
Muscular tissue
Specialized for voluntary and involuntary movement of various organs
Nervous tissue
Specialized for reception and conduction of stimuli and impulses
simple squamous epithelia
- flattened cells (like carpet)
- facilitates movement of gases and other molecules (blood, capillaries, lungs)
simple cuboidal epithelia
- short, boxlike cells
- active secretory of absorptive functions (kidney, salivary glands)
simple columnar epithelia
- tall elongated cells
- often associated with highly absorptive surfaces (intestinal tract)
stratified squamous epithelia
- layered to withstand mild mechanical abrasion (layers of cells on top of one another)
- basal cells push upward (oral cavity, esophagus)
Transitional epithelia
- stratified but specialized to accomodate stretching (urinary tract, bladder)
Noncellular components
- remove cells from fluids and connective tissues
Body fluids
- Multicellular animals contain two fluid compartment:
- intracellular space (within cells)
- extracellular space (outside cells)
Blood plasma
fluid portion of blood outside cells
- extracellular space
interstitial fluid
occupies space surrounding cells
extracellular structural elements
SUPPORTIVE MATERIAL
- loose connective “tissue”
- cartilage
- bone
-cuticle
Asymmetry
no body axis and no plane of symmetry
Spherical symmetry
- any plane passing through center divides equally
- rare, only found in unicellular eukaryotes (radiolarians)
- no differentiation along an axis
Radial symmetry
- divided equally by more than two planes passing through the longitudinal axis
- rare, eg., polyps, some sponges
- most forms are modified (pentaradial)
Bilateral symmetry
- body parts oriented around a single anterior to posterior axis
- division around the saggital plane results in two equal halves
- associated with cephalization
- animal usually moves head first such that the anterior of the animal confronts environment first
The coelom
- fluid filled cavity between outer body wall and gut
- enables internal organ to grow larger and become more sophisticated
- fluid cushions internal organs which prevents injury
- allows compartmentalization of body parts
- acts as a hydrostatic skeleton, providing support for soft-bodied animals
Acoelomate
- no true coelom (no body cavity)
- region between the ectoderm and gut are occupied
- FLATWORM
- parenchyma (mesoderm)
Pseudocoelomate
- possess a pseudocoel
- “tube within a tube” arrangement
- ROUNDWORM
- no peritoneum (no cellular membrane derived from mesoderm)
Coelomate
- true coelom lined with peritoneum
- EARTHWORM
What is the body cavity within bilateral animals?
The coelom
Paraphyletic group
- most recent common ancestor is also the ancestor of animals, plants and fungi
- the group does not include all the descendants of the common ancestor
- NOT A CLADE
What are the three locomotions in unicellular eukaryotes?
- Ciliary motion
- Flagellar motion
- Amoeboid motion
Ciliary motion
Cilia: hair-like outgrowths from surface of the cell
- fastest ciliates are up to 720 cm/h
- CILIATES ARE THE FASTES UNICELLULAR EUKARYOTES
Flagellar motion
Flagella: whip-like outgrowth from surface of cell
- fastest flagellate up to 72 cm/h
- Flagellates are only 1/10 the speed of ciliates
Amoeboid locomotion
Pseudopodia: a free form projection of the cell
- Pseudopodia are extremely slow (only 1.8 cm/h top speed)
Ciliary locomotion
A cilium propels water parallel to the surface of attachment
- provides the means for ‘directed’ movement
- prevents stagnant layer of water accumulating around the body
Ciliary beating (circular motion)
a circular motion with 2 components:
- power stroke
- recovery stroke
Power stroke
stiffened cilia propel water parallel to cell surface
- moves from the left
recovery stroke
cilia bends towards body to reduce resistance
- moves to right direction
What is ciliary locomotion?
- the body of is covered with cilia and the movement of organism is achieved by ciliary beating
What is metachronal beating?
sequential action as opposed to synchronizing
- Cilia beat can reverse permitting
avoidance reaction
- Cilia beat obliquely (i.e. at an angle),
therefore organism moves in a spiral path
Flagellar locomotion
Flagellum propels water parallel to the main axis of the flagellum
- bending in opposite directions along the flagellum to produce a wave action along the flagellum
- flagellated cells usually have only a few flagella or even just a single flagellum
Tractellum
- a flagellum that draws water toward and over the cell body
What is the direction of movement in sessile flagellates?
- Moves water across cell surface
(i.e. prevents stagnation) - Brings food particles towards
the organism
Pulsellum
– a flagellum that
propels the cell in a cell body
first direction.
In free-living flagellates:
- Moves organism through
water like a tadpole
AMOEBOID LOCOMOTION
- Classic amoeboid locomotion uses cytoplasmic
streaming & large blunt pseudopodia (lobopodia)
2 forms of actin:
- Globular actin (endoplasm: fluid state, plasmasol): subunits dissociated
- Filamentous actin (ectoplasm: gel-like, plasmagel); subunits into filamets, filaments crosslink
