The Integument: List the embryonic germ layers that the epidermis and dermis are derived from (be specific for the dermis). (2 points) Dermis is derived from the mesoderm. It is made up of layers of cells that originate from the bottom most layer called the stratum basale, which is constantly undergoing mitosis. The epidermis is derived from the ectoderm. The development of hair, feathers, teeth, and scales all depend on the same structure. What is it called? (2 points) Dermal papilla How do reptile scales differ from fish scales? (2 points) A reptiles scales are in the epidermis of the skin whereas a fish’s scales are in the dermis of the skin which is located underneath the epidermis. All reptilian scales have a dermal papilla underlying the epidermal part. Compare and contrast rhino horns, antlers, and giraffe horns in terms of contributions by the epidermis and dermis. (4 points) Horns are composed of a bony core covered with a sheath of keratin. Unlike antlers, horns are never branched. Rhino horns differ from true horns because their horns have no core or sheath. They are made up of many epidermal cells and bundles of dermal papillae, extensions of the dermis. Cells from each papilla form a horny fiber similar to thick hair. These fibers are not true hairs. True hair grows from follicles that extend into the dermis, whereas rhino horns grow from dermal papillae which extend up into the horn. Giraffe horns are paired, short, and permanent bony processes that are covered with skin and hair. They differ from other horns in that they do not project from the frontal bones, but lie over the sutures between the frontal and parietal bones. Antlers are not formed in the epidermis and do not consist of keratin but are... ... middle of paper ... ...rdle is attached to the axial skeleton. (5 points) The fins of fish have some basic structures in common. What are the two sets of skeletal elements that comprise the basic fish fin? What kind of paired fin has: 1) both preaxial and postaxial elements, 2) only preaxial elements? (4 points) Two sets of skeletal elements that make up the basic fish fin are Archipterygial and Metapterygial fins. The archipterygial has both preaxis and postaxial elements. Metapterygial has only preaxial elements. How do artiodactyls differ from perissodactyls? (2 points) The Artiodactyls are even-toed ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in odd-toed ungulates called perissodactyls. Perissodactyls have an odd number of toes and the middle toe on each hoof is usually larger than its neighbors.
To begin we will look at the integumentary system and its entire multitude of functions. The main components of the integumentary system are the skin, hair, nails, glands and nerves. For the purpose of this paper we will focus mainly on the levels of the skin and their functions. While the integumentary
...ons in the size and distribution of the major collagen fibrils of the dermis. J Invest Dermatol. 108(3):241-7 [PubMed: 9036918] Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/9036918
It was thought that they used their heads in combat or mating contests, but that was disproved fairly recently, which I will discuss later in the paper. Both Ceratopsians and Pachycephalosaurs were “bird-hipped” and both of these suborders contained a backward pubic bone. Both were Marginocephilia, or “fringed heads”, which is one of three clads under the Orinthiscia order. They were also herbivore dinosaurs that inherited their fringe at the back of the skull from earlier ancestors. 2.
Not only are giraffes the tallest animals in the world, they are also one of the most recognizable. Their characteristic long necks quickly captivate any audience. That being said, it is not commonly known that there are thought to be nine subspecies of Giraffa camelopardalis. In fact, there is increasing evidence that these could potentially be separate species in their own right. This paper will discuss where giraffes fit in the Tree of Life and identify the giraffe’s closest relatives, differentiate and analyze the similarities and differences between the nine subspecies, and, finally, explore any debate revolving around the phylogeny of the subspecies.
Hair is considered one of the components of the integumentary system, along with the skin, nails, glands and nerves. Mammalian hair has many functions including protection from environmental factors and the ability to disperse sweat gland products such as pheromones. Almost every part of the human body is covered by hair except for the palms, hands and bottoms of the feet. On average, every person has about five million hairs; each of these hairs is born from a follicle or tiny tube-like structure that grows into the dermis layer of the skin. Oftentimes this follicle even reaches the subcutaneous layer, which is made of fat and connective tissue. (UXL Complete Health Research, 2001)
The skeletal system frames our entire bodies and protects our fragile inner organs. We have two major types of bone in our body: compact bone and spongy bone. Compact bone is dense and looks smooth, while spongy bone is comprised of small needle-like pieces of bone with lots of open spaces. Our body contains 206 bones. The skeleton is separated into axial and appendicular sections. The axial skeleton includes the bones in the longitudinal axis of our body. The appendicular skeleton consists of the limbs and girdles of the body, such as our arms and shoulders. There are four different classifications of bone, determined by their shape. Long bones are shafts with ‘heads’ on both sides. Our limbs contain mostly long bones. Short bones
Throughout time, one theory has remained constant in terms of why giraffes developed longer necks. The idea, which was presented by Charles Darwin states quite simply that giraffes selected for longer necks in order to reach the food that was higher off the ground during the dry season. No one has ever challenged that idea until 1996. Initially, Gould argued that "the story-the giraffe evolved its long neck in competition to reach scare foliage-is supported by no evidence" (18). That's when two scientists, Robert Simmons and Lou Scheepers made the claim that necks evolved for a very different reason: sexual selection. Within this paper, information will be presented that argues both for and against the theories made by Darwin and Simmons and Scheepers.
Germinal epithelium, known as Germ Layer, is a group of cells, formed during animal embryogenesis. Few primitive animals’ tissues are derived from two germ layers, the endoderm and ectoderm; while most animals are derived from three germ layers, the ectoderm, mesoderm and endoderm. Germ layers are known as the primary layers of cells in an embryo of an animal. As the embryo develops, the cells differentiate to form the various body tissues. In 1817, Caspar Friedrich Wolff was the first to observe the early organization of embryos in leaf-layers.
Skin Anatomy, Physiology, and Assessment. Rn.com AMN Healthcare Education Services. Retrieved November 11, 2013, from:
Mojetta wrote about prehistoric sharks, and the history of these creatures. According to Angelo Mojetta, author of Sharks, Cladoselache genus, one of the first prehistoric sharks, was buried in sediment that kept it preserved. Unlike other sharks, Cladoselache genus had a circle of tiny plates around it’s eyes for protection against it’s victim’s attempts to fight back. These sharks lived over 400 million years ago. Sharks of the past could mostly be identified by their teeth, because shark’s bodies are made of cartilage. Another shark that was focused on was called, Stethacanthus. This shark had a very unique look. Stethacanthus had a brush like decoration on the top of it’s head, and an extra fin like part that had the same bristle like decorations on it. These characteristics were thought to be used as suction cups, to hitch rides from larger fish. One of the most famous sharks that looks like an over...
The second layer of the skin is called the dermis and is also known as the middle layer. The dermis is what holds the body together. The dermis has layers to it as well as the epidermis. There are two layers to the dermis, the papillary layer and the reticular layer. The cells of the dermis are fibroblast, macrophages, mast cells, and scattered white blood cells (wbc’s). the dermis is richly supplied with nerve fibers and BV;s. dermal BV’s is also a part of the integumentary system, dermal BV,s have converging and diverging vessels that ar...
The integumentary system is composed of the skin and the structures related to the skin, which include the hair, the finger nails, the sensory receptors and the glands (Shier, Butler, & Lewis, 2009). This system has an important function since it provides protection to the body, helps to maintain body temperature, and contains sensory receptors (p.117). The skin has essential function such as regulating homeostasis and body temperature, also delaying the loss of water from deeper tissues, storing sensory receptor, synthesizing biomechanical, and discharging waste from the body (p.117). The skin has two layers: the epidermis (outer layer) and the dermis (inner layer) (p.117). There is also a subcutaneous layer or hypodermis (p.117). According to Shier, Butler, and Lewis 2009 “as its name indicates, this layer is beneath the skin and not a true layer of the skin” (p.117). This layer has the blood vessels that supply the skin (p.117).
The morphology of whale sharks is mostly similar to aquatic fish species, but many specific traits help differentiate them from the rest. Whale sharks are the largest fish in the world and can reach a size of around 20 meters (Martins, C., and C. Knickle). This is often compared to the size of a school bus. The shark has a very large transverse mouth. They have 5 very large gill slits and have a larger first dorsal fin compared to the second one (Whale Shark). They have a distinctive spotted “checkerboard” pattern with stripes (Martins, C., and C. Knickle). It is not exactly known why they have this specific body marking. It is believed that the body markings act as a camouflage. The strange thing about whale sharks is that they have 300 rows of teeth that play no role in feeding (Martins, C., and C. Knickle).
... At the age of six months, a giraffe’s coat turns dark brown and white. They drink their mother’s milk and they like to eat grass too. When they are one year old, their horns are thick, their hooves are big, and they are so tall that they can reach the top of some trees.
I have chosen to do my essay on the largest organ of the body, skin. It has several functions vital to the survival of the body as I will discuss in the following paragraphs.