Porifera This phylum consists of animals such as sponges Characteristics Symmetry Asymmetrical-

The outer most layer of the skin or Epidermis contains stratified squamous, keratinized, epithelial tissue; which lacks blood vessels, and the cells are packed closely together (Sloane, 1994, p.85)

The skin is divided into three different parts including the epidermis, dermis, and hypodermis. The epidermis is the outermost layer of the skin. This region of the skin has no blood cells or blood vessels running through it. All of the nutrients that the epidermis needs are received through diffusion from the dermis. The epidermis is made up of stratified squamous epithelial cells. The epidermis is made of five separate layers: the stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and the stratum corneum. Starting at the innermost layer, the stratum basale is where mitosis of keratinocytes takes place. This layer of the epidermis also contains melanocytes which give the skin it’s pigment. As mitosis takes place in the stratum

9. Pacinian Corpuscles connective tissue wrapped around a nerve ending located in the deep layers of skin.

The three layers that make up healthy skin: Epidermis, Dermis and Hypodermis. Epidermis is composed of keratinized, stratified squamous epithelium. This layer provides a thick, water proof protective covering over the underlying skins. The dermis layer is composed of primarily of dense, irregular, fibrous connective tissue that is rich in collagen and elastin. The dermis contains blood vessels, nerve ending, and epidermally derived cutaneous oranges such as sweat glands, sebaceous glands and hair follicles. The last layer is Hypodermis this layer is composed primarily of loose dead skin. The fat layer provides cushioning and insulation for

of the skin, skeletal muscles, bones and joints. The visceral division on the other hand carries

The outer germ layer is the ectoderm that forms the outer part of the body (the skin) and the nervous system. The endoderm, the inner germ layer, forms many inner structures, including the digestive tract and many glands associated with it. Lastly, the mesoderm is the middle layer which forms much of the skeleton and muscles.

The first type of tissue found in the human body is epithelial tissue. These types of tissue are found covering the whole surface of the body, lining of cavities, hollow organs and tubes. The cells a very closely packed and are arranged in one

There are three primary layers of the skin: the outer layer, the epidermis and the layer beneath, the dermis and the hypodermis. The epidermis is thin, tough and waterproof while protecting the body from outside bacteria invading the body. It also contains keratinocytes which are from the basal layer which is the deepest layer of the skin. The keratinocytes reach up to the epidermis, shed and new ones form again. The dermis is the second layer of the skin and is the thickest. It is made from fibrous and elastic tissues which are made from fibrillin, elastin and collagen to create the strength and flexibility. It also contains sweat and oil glands, nerve endings, blood vessels and hair follicles. Sweat glands help the body cool off during heat

The layers of the epidermis from deep to most superficial are the stratum basale, stratum spinosum, stratum grandulosum, stratum lacidum, and the stratum corneum. Each of these layers are unique due to the type of cells located in them which they are named after. They all together make up the epidermis, an avascular, superficial, and made up of epithelial cells.

.*They are omnivorous, plantigrade and highly social animals *Body is covered with hairs (except palms, soles and face) *Limbs have five digits.

Bone- hard tissue consisting of a collagen framework that is filled in with minerals such as calcium

Stratum Granulosum is another shallow layer; it is made up 3 to 5 layers of flat packed grainy cells called kertaohylain cells which act similar to a water filter, to absorb any foreign bodies. This eases water loss and keeps up hydration in the skin.

If the spongocoel of the sponge is too large, there will be areas in the sponge where the water is not circulating. If that happens, the amount of water flow and the feeding efficiency is lowered. If the spongocoel is too small, there will not be that much water flow; therefore, the feeding efficiency will still be low. To maximizing the amount of water flow and the feeding efficiency, sponges have adapted their morphology. The three different types of morphology are asconoid, syconoid, and leuconoid. The asconoid is the simplest structure while the leuconoid is the most complex structure. The leuconoid is the most complex because it has more pathways to the spongocoel which allows a higher feeding

The skin has three regions, but only two of them are distinct. The three regions are the Epidermis, the Dermis, and the Hypodermis; the two that are distinct are the Epidermis and the Dermis layer. The epidermis is the physical layer we can see and touch while the dermis is the layer underneath the epidermis that we can not

Look at the photo of a Pacinian corpuscle. Notice the onion-like bulb of connective tissue. Describe briefly —