BIO quiz 6

What is a animal?

Eukaryotic (membrane bound organelles)

Heterotrophic

Cells lack walls (plasma membrane instead)

Motility

Embryos that go through blastula stage

Poriferans (sponges)

8,500 species

lack true tissue layers

lack symmetry

no nervous system

have three groups

• Demosponges

• Glass sponges

• Calcarea

Demosponges

make up 90% of sponges (marine and freshwater)

Glass sponges

Have intricate silica skeletons (entirety marine)

Calcera sponges

Made of calcium carbonate skeletons

Sponge cell types

Pinacocytes

Choanocytes

Archeocytes

Pinacocytes

Epidermal cells which contract to move water

Choanocytes

Wave flagella to produce a current

Archeocytes/ Amoebocytes

cells that can digest food, store nutrients, secrete collagen

Sponge body plan

Central cavity

Ostia

Osculum

Skeleton (made of calcareous or salicaceous spiculas held together with collagen)

Spicules

biominerals that provide structure and defense

what is tissue?

A group of cells that form a specific function

Differentiate from 2-3 germ layers during embryonic development

Tissue (?) organization

Germ layers

Tissue types

Body plans

Germ layers

ectoderm, mesoderm and endoderm

Tissue types

Epithelial

connective

muscle

nervous

Body plans

Asymmetric

Bilateral symmetry

radial symmerty

All animals

Eumetazoans — have true tissue

diploblastic animals primary germ layers (jellyfish, corals, sea anemones, & comb jellies):

Endoderm

ectoderm

Cnidaria

Precambrian to present

characterized by stinging cells (nematocysts); nerve nets

• Anthozoans (sea anemones, sea pens and corals)

• Scyphozoans (jellyfishes)

• Hydrozoans (Obelia and Hydra in lab)

• Cubozoans (box jellies)

Cnidarian life cycle

Alternation between polyp a medusa stages

• Sexual reproduction: gametes (released by medusa) → zygote → blastula → free-swimming planula larvae → polyp

• Polyps can reproduce sexually or asexually by strobilation (budding of disc-like structures from gonozooids)

Connective tissue

• Consists mainly of cell products (very diverse group), mostly collagen

• Derived from the mesoderm

• All tissues are made up of cells within an extracellular matrix and some cells secrete more of that extracellular matrix

Examples:

• Fat (adipose) tissue

• Cartilage

• Bone

- Osteocyte cells

- Haversian canals

• Blood

Muscle tissue

• Perform work through contractions

- Actin & myosin

• Smooth muscle

- Found in blood vessels, intestine, and other body tubes

- Elongated, spindle-shaped cells

- No active control & no striations

- 1 nucleus per cell

• Striated or skeletal muscle

- Composes muscles you have control of

- Very long cells with multiple nuclei on outside

• Cardiac muscle

- Only in the heart

- Branched cells

- Connected by intercalated discs

- 1-2 nuclei

Epithelial tissue

Covers outside of body and lines surface of the organs • Mainly a protective layer

• Keeps things out, but also in!

Number of layers

• Simple – one layer

• Stratified – more than one layer

• Pseudostratified – simple, but looks multilayered (usually irregular shapes

Cell shape

• Squamous – flattened sheet-like

• Cuboidal – cube shaped

• Columnar

Nerve tissue

• Made up of neurons and glial cells

• Neurons carry electrical signals over long extensions (axons) to communicate with other neurons, muscle cells or secretory cells

• Glial cells do not carry electrical signals but support neurons (astrocytes shown here are a type of glial cell)