BIO 311D 2nd Edition Exam 3 Study Guide Lectures 21 32 Lecture 21 3 1 What are distinguishing traits of animals What are major characteristics of animal cells Animals cannot construct all of their own organic molecules and so in most cases they ingest them either by eating other living organisms or by eating nonliving organic material Animals ingest their food then use enzymes to digest it into their bodies Animals lack structural support of cell walls Instead a variety of proteins external to the cell membrane provide structural support to animal cells and connect them to one another The most abundant of these proteins is collagen which if found only in animals Animals have two types of specialized cells not found in other multicellular organisms muscle cells and nerve cells Muscle and nerve tissues are responsible for moving the body and conducting nerve impulses respectively In the haploid stage of animal reproduction sperm and egg cells are produced directly by meiotic division Animal cells lack a cell wall and there is an imbalance of organelles 3 2 Distinguish tight junctions gap junctions desmosomes anchoring and tell the function of each Tight junctions the plasma membranes of neighboring cells are very tightly pressed against each other bound together by specific proteins Forming continuous seals around the cells tight junctions prevent the leakage of extracellular fluid across a layer of epithelial cells Gap junctions provide cytoplasmic channels from one cell to an adjacent cell and in this way are similar in their function to the plasmodesmata in plants Allows cells to communicate with one another Desmosomes anchoring fastening cells together into strong sheets Attach muscle cells to each other in a muscle 3 3 Wednesday Describe some specializations cell shape which organelles abundant cellcell junctions found in these cells a sperm intestine transport epithelium pancreatic secretory epithelium a macrophage heart muscle Sperm a lot of mitochondria to produce energy for movement flagella haploid nucleus membrane proteins Small intestine transport epithelium specialized for taking up digested foods a lot of surface area to absorb all the food layers membrane proteins transport proteins Pancreatic secretory epithelium produces and secretes insulin a lot of rough ER Macrophage large white blood cell engulfs and breaks down particles a lot of lysosomes moving cytoskeleton nothing anchoring amoeba movement no cilia or flagella Heart muscle communicates immediately with neighbors when one pulls all move gap junctions desmosomes mitochondria for energy 3 4 Name the four major animal tissue types tell how they differ from each other and give examples Epithelial Tissue cover the outside of the body and line organs and cavities within the body They are closely packed often with tight junctions therefore function as a barrier against mechanical injury pathogens and fluid loss For example the epithelium that lines the nasal passages is crucial for olfaction the sense of smell Connective Tissue Consists of a sparse population of cells scattered through an extracellular matrix holds many tissues and organs together in place There are three kinds collagen fibers provide strength and flexibility reticular fibers join connective tissue adjacent tissues and elastic fibers make tissues elastic Muscle Tissue Responsible for nearly all types of body movement Consists of filaments containing the proteins actin and myosin which together enable muscles to contract There are three types of muscle tissue in the vertebrate body skeletal smooth and cardiac Nerve Tissue Functions in the receipt processing and transmission of information Nervous tissue contains neurons or nerve cells which transmit nerve impulses as well as support cells and glial cells or simply glia 3 5 Tell how animal embryos are organized and name the three embryonic germ layers The zygote of an animal undergoes a series of mitotic cell divisions called cleavage Three rounds of cell division form an eight cell embryo In most animals cleavage produces a multicellular stage called a blastula The blastula is typically a hollow ball of cells that surround a cavity called the blastocoel Most animals also undergo gastrulation a process in which one end of the embryo folds inward expands and eventually fills the blastocoel producing layers of embryonic tissues the ectoderm outer layer and the endoderm inner layer The pouch formed by gastrulation called the archenteron opens to the outside via the blastopore The endoderm of the archenteron develops into the tissue lining the animal s digestive tract The endoderm the mesoderm and the ectoderm are the three embryonic tissue layers 3 6 Tell major evolutionary trends in the animal kingdom with respect to embryonic tissue layers 2 3 tissue layers gut one opening or tube with mouth anus and body symmetry radial bilateral Embryonic tissue layers Through the process of gastrulation the embryo becomes layered As development progresses these concentric layers called germ layers form the various tissues and organs of the body Ectoderm the germ layer covering the surface of the embryo gives rise to the lining of the digestive tract or cavity and organs such as the liver and lungs of vertebrates Animals that have only these two germ layers are said to be diploblastic All bilaterally symmetrical animals have a third germ layer called the mesoderm which fills much of the space between the ectoderm and the endoderm Animals with bilateral symmetry are also known as triploblastic Gut Animals with an incomplete digestive system are those in which the digestive tube has only one opening cnidarians platyhelminthes Animals with a complete digestive system are those in which the digestive tube has two openings mouth and anus all other animal phyla with the exception of poriferans that do not have any digestive tube In animals with incomplete digestive tubes the digestion is mixed it begins in the extracellular space and finishes in the intracellular space In animals with complete digestive systems extracellular digestion within the digestive tube predominates Body Symmetry Radial animals do not have a left and right side This equips them to meet the environment equally well from all sides Examples seas anemone jellyfishes A bilateral animal such as lobster has a left and ride side which equips them to move actively from place to place Most bilateral animals have a central nervous system that enables them