ASU BIO 181 Exam 3 2025

Excitatory synapses make the post-synaptic cell less likely to fire. - -False The neural tissues are - -Spinal cord, sensory neurons, and brain How do the glial cells (i.e., myelin sheath) speed up the firing of neurons? - -The cell wraps extensions of a fatty insulating substance (myelin) around the axons of neurons. The action potential is: - -A result of the movement of ions. Receptors are made from membrane-bound polyribosomes. - -True List the 4 types of glial cells and list a phrase to describe their function. - -Microglia: cleans up cellular debris- Astrocytes: support and repair neurons- Schwann Cells: myelinates axons of the neurons in the PNS- Satellite: form the brain-blood barrier within the CNS Acetylcholine exocytosed from the presynaptic cell travels to the postsynaptic cell to start the action potential in the postsynaptic cell. - -True When the presynaptic cell contacts a muscle cell, the synapse area is called a motor end plate. - -True Potassium ions are at high concentrations inside of cells including in neurons. - -True The membrane potential (resting potential) is largely set by the Na-K- ATPase pump. - True Draw an action potential in the axon of a neuron and indicate which ions flow into the neuron and out of the neuron as the action potential passes at the point where the electrodes are in the cell. Be sure to assign on the Y-axis the mV of each of these areas. This should be as described in my lectures. - - Fast neurons as described in lecture are fast because they are surrounded by a type of glial cell that results in a myelin coating. - -False Voltage-gated ion channels open when a protein binds to the receptor. - -False The cell body refers to the part of the neurons that begin at the dendrites and extend to the axon terminal. - -False Only pre-synaptic neurons are coated with myelin. - -False ASU ASU The post-synaptic cell can be: - -In glands, muscle cells, neurons Fast neurons as described in lecture require cytoplasmic signal transduction to open an ion channel. - -False Acetylcholine esterase breaks acetylcholine into muscarinic acid - -False Excitatory synapses cause hyperpolarization of post-synaptic cells. - -False Excitatory synapses cause depolarization of the post-synaptic cell. - -True The axon hillock in the pre-synaptic neuron fires based on temporal and spatial summation of inputs. - -True The receptors in post-synaptic cells are the basis on which the synapse can be defined as inhibitory or excitatory. - -True The resting potential of neurons is: - -The answer is not on this list Draw a neuron, and label all the parts as described in lecture. - - The central nervous system (CNS) contains: - -There is no correct answer The terminal web: - -is a site of exocytosis In the motor end plate, the event that is the immediate trigger for exocytosis is: - Calcium ions The autonomic nervous system contains the sympathetic and the parasympathetic nervous system. - -True The axon from a pre-synaptic cell contacts the axon of another neuron. - -False Briefly explain why the action potential flows only from the axon hillock to the terminal web. - -The action potential originates from the axon hillock which initiates the flow of the action potential because of the presence of higher density voltage-gated ion channels. Explain how insulin and glucagon regulate the balance (i.e, homeostasis) between glycogen and glucose when epinephrine (i.e., adrenalin) is not involved. - -- blood glucose rises - b-cells of pancreas release insulin - insulin stimulates cells to use glucose and convert glucose to glycogen and fat - blood glucose falls - pancreas stops releasing insulin - cells use glycogen and fat for energy ASU ASU - blood glucose falls too low - a-cells release glucagon - glucagon stimulates liver to convert glycogen back to glucose The Parasympathetic Nervous System is triggered is trigger to act by exposure to epinephrine. - -False Vitamin D causes the parathyroid to inhibit new PTH synthesis. - -True Insulin is a ligand. - -True What could the stress of taking an exam do to your glucose levels in various parts of the body? - -The stress could cause the sympathetic nervous system to kick in and increase glucose into the blood Vitamin D is really a hormone. - -True Vitamin D is synthesized from cholesterol - -True Your mom came back from her medical appointment and said that the M.D. told her she had low bone density. What medical problem could this cause and what hormones/endocrine glands in the body are involved? - -Osteoporosis, the parathyroid hormone released on the thyroid glad has a large role in bone density. Too much parathyroid hormone causes calcium loss in the urine at the expense of bone. Where do fats in the body play a role in balance between glucose and glycogen? - -If there is extra glucose present in a cell the reserve glucose is put in reserve as glycogen (stored as fat) mainly in the liver and muscle cells to be used at a later time Insulin is produced by alpha cells. - -False When the Sympathetic nervous system is triggered glycogen is broken down to glucose to provide more energy. - -True The medulla of the adrenal gland produces epinephrine (i.e., adrenaline). - -True When epinephrine is released it triggers activation of which part of the Autonomic Nervous System? - -sympathetic The left ventricle of the heart contains more muscle. - -True Tidal breathing causes the incoming air to mix with some older air in the lungs. - -True The two circuits in the heart and the cardiovascular system have the same blood pressure. - -False ASU ASU To prevent back flow of blood in the heart there are __________________. - -valves Oxygen is distributed throughout the body by: - -The circulatory system. Nutrients and oxygen can leave the arteries and arterioles to reach the cells. - -False Blood moves very rapidly in the capillaries. - -False When oxygen passes from the lungs into the circulatory system as a gas, how many cells does it have to pass through to be in the circulatory system? - -2. Alveoli and capillary cells. The partial pressure of oxygen in the lungs causes it to load into the circulatory system. - -True When arterial blood pressure falls the body compensates to raise the blood pressure. Explain this process. - -The kidneys release renin which activates angiotensin (makes vessels constrict) which causes arterial pressure to rise When the ventricles contract blood is pushed out into the artery and the artery st