Biology 252 Exam 1 Questions And Answers Solved 100% Correct!!

What is homeostasis? - Answer-how varied components of living things adjust to maintain a constant internal living environment. There is a balanced dynamic state! Diseases result from homeostatic imbalances (diabetes) What are the levels of organization? - Answer-chemical - cellular - tissue - organ - organ system - organismal What is the nervous system made of? - Answer-The Central nervous system (brain and spinal cord) and the peripheral nervous system (cranial nerves and spinal nerves). What is the big picture of the nervous system? What does this mean? - Answer-Input - Processing - Output. Explain. Most of our wiring is _____. - Answer-insulated. Neuron - AnswerDescribe the soma, neurofibrils, Nissl bodies, dendrites, axon and axon hillock. - Answer-Soma- body of the neuron cell. Neurofibrils- work with microtubules to compartmentalize rough ER into Nissl bodies. Nissl bodies- help identify neurons in tissue sections with mixed cell types Dendrites- primary site for receiving signals from other neurons axon hillock- nerve fiber where axon originates axon- conducs nerve signals to remote point from the soma. contains Varicosities secrete NTs. How are neurons classified? - Answer-By number of processes extending from the soma. What is the difference in multipolar nerons, bipolar neurons, and anaxonic neurons? - Answer-multipolar - one axon with multiple dendrites. Includes most neurons of the brain and spinal ar- one axon and one dendrite. Anaxonic- multiple dendrites, no axon. Communicate through dendrites and produce no action. found in brain, retina, and adrenal medulla. What is axonal transport? - Answer-two way passage of proteins, organelles, and other materials along the axon. What is anterograde and retrograde transport? - Answer-anterograde- moves down the axon, away from the soma. retrograde- moves up the axon, towards the soma. What are 3 properties that enable communication with other cells? - Answer-1. Excitability (response to stimuli or environmental change). 2. Conductivity ( production of electrical signals that are conducted to other cells at distant locations). 3. Secretion (when a signal reaches the end of a nerve fiber, neuron secretes a NT that crosses gap and enters the next cell). What are sensory neurons? - Answer-(dealing with the five senses) They are a part of the PNS (afferent). They conduct signals from receptors to the nervous system. Detect stimuli and transmit info TOWARDs the CNS. somatic: bones, joints, and muscles visceral: comes from inside us like internal organs (organized by location) What are interneurons? - Answer-They lie within the CNS. They receive signals and carry out the integrative function of the nervous system. They take info from sensory neurons in the PNS and make decisions. What are motor (efferent) neurons? - Answer-sends signals AWAY from the CNS to primarily muscle cells (effector). somatic: skeletal muscle autonomic: things you can't control (like digestion, heartbeat, glands in hormonal signaling) -- smooth muscles, cardiac muscles, hormones.(organized by target cell) What is the myelin sheath? - Answer-A whitish, fatty segmented sheath around most LONG (not all) axons. They increase the speed of nerve impulse transmission. It is formed by cells. The cell has concentric layers of membrane that make up the myelin sheath