Answers Chapter 32 Tissues Homeostasis Osmoregulation Study Questions 1 Name the four different kinds of animal tissues Epithelial tissue Connective tissue Nervous tissue Muscle tissue 2 Draw a nerve cell neuron and label all of its parts What are the functional differences between a neuron and a glial cell Please refer to the diagram on the ppt for this chapter for the structure of a nerve cell neuron The neuron is adapted for transmission of a signal or nerve impulse starting at the tips of the dendrites and progressing down the axon where the signal is transmitted to the next neuron or causes a particular response in an effector cell usually a muscle or gland Glial cells physically and metabolically support neurons and are found interspersed among the axons and cell bodies of the neurons 3 What are the three different kinds of muscle tissue What are the features that unite them and what features make them different from each other The three kinds of muscle cells include skeletal muscle smooth muscle and cardiac muscle All three types of muscle are composed of muscle fibers or cells that contain the contractile proteins actin and myosin and excitation causes contraction or shortening of the muscle fiber or cell Skeletal muscle is composed of many tubular fibers connected end to end bundled together for the length of the entire muscle Skeletal muscle is striated by virtue of the pattern of actin and myosin along the length of each fiber also known as sarcomeres Each cell is discrete and contains multiple nuclei Skeletal muscle is under conscious control Cardiac muscle is striated for the same reason as skeletal muscle but the tubular muscle cells are branched and connected to each other via intercalated discs Cardiac muscle is responsible for the unconscious contraction of the heart Smooth muscle also known as involuntary muscle is found in muscular organs within the body that are not under conscious control e g the stomach Actin and myosin are present in the spindle shaped smooth muscle cells but these proteins do not form the patterns observed in skeletal and cardiac muscle thus explaining its name Smooth muscle is control ed by both nervous and hormonal input 4 What are the functional differences between smooth muscle and skeletal muscle with respect to where they are found in the body Smooth muscle causes the movement expansion and or constriction of the organs that possess it and is affected by autonomic or unconscious control via nerves and hormones Skeletal muscle is found in the limbs extremities and moving parts of the body that are under conscious control 5 What are the unifying features of all types of connective tissue All types of connective tissue consist of living cells that are surrounded by a non living matrix The cells can be of various types adipocytes fibroblasts chondrocytes osteocytes red blood cells white blood cells etc and the matrix can be a hard solid as with the calcium phosphate matrix of bone or liquid as with the plasma of blood Sometimes the matrix contains fibers as in loose and dense connective tissues 6 Name all six types of connective tissue and where they can be found in the body Loose connective tissue under epithelial layers and surrounding organs dense connective tissue tendons and ligaments bone the skeleton cartilage joints between bones adipose storage areas padding for the heart and kidneys blood within the vessels of a closed circulatory system 7 What are the six functions of epithelial tissue Identify the type of epithelial tissue associated with each function Name a place in the body where each can be found Lining organs and cavities Secreting substances such as mucus hormones thyroid gland Absorbing nutrients Simple columnar as in the small intestine Protecting orifices and the outside of the body Stratified squamous as in the skin mouth anus Movement of mucus or oocytes Pseudostratified ciliated columnar as in the trachea oviduct Gas nutrient exchange Simple squamous as in the lungs capillary beds Simple cuboidal such as in the coelom and digestive organs Simple columnar or simple cuboidal as in the stomach or 8 What is meant by the polarity of epithelia Epithelial cells typically have basal and apical sides that perform different functions For example the basal side of the columnar epithelial cells of the small intestine is attached to the basal lamina a thickened layer of extracellular matrix and is not at all absorptive whereas the apical side facing the lumen of the small intestine is the absorptive side and has transport properties specific to it that allow absorption of nutrients 9 Why does transport of salt from the environment to the blood of a freshwater fish require ATP Transport of salt Na Cl K etc into the blood of a freshwater fish requires ATP because these ions must be accumulated against very high concentration gradients the concentration of these solutes is very low in the water and much higher in the intracellular fluids of fish 10 Why aren t any freshwater aquatic animals osmoconformers An osmoconforming animal keeps its body fluids blood plasma intracellular fluid and interstitial fluid ISF at the same osmolarity in mOsm L as the external environment Freshwater has an osmolarity of about 15 mOsm L which would be far too low to include the internal concentration of solutes needed for normal physiology a minimum of about 300 mOsm L 11 A camel that stands in the sun requires more water when its fur is shaved off although the body temperature remained the same What can you conclude about the relationship between osmoregulation and the insulation provided by the fur The fur of the camel provides insulation against high environmental temperatures and actually helps it keep cool The camel with fur will sweat less than a camel without fur and more water would be conserved and thus available for osmoregulation 12 How is it possible that the kangaroo rat which lives in the American Southwest survives on a diet of dry seeds and no water The metabolic production of water resulting from the oxidation of its food is enough for this small mammal that is adapted to its arid environment The nephrons in the kidneys of these animals have very long loops of Henle allowing them to produce highly concentrated urine thus conserving water 13 Compare the properties of ammonia urea and uric acid as chemical avenues for ridding the body of nitrogenous waste Ammonia is toxic especially at high concentration as it forms a strong base