ASU BIO 181 Exam 2 2025

Potassium ions are at high concentrations inside of cells including neurons - -True The neural tissues are: - -Spinal cord, sensory neurons, and brain Excitatory synapses cause hyperpolarization of post-synaptic cells - -False (causes depolarization) Excitatory synapses cause depolarization of the post-synaptic cell - -True 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 (they are ionotropic receptors meaning they open on their own) The membrane potential (resting potential) is largely set by the: - -Na-K-ATPase pump The receptors in post-synaptic cells are the basis on which the synapse can be defined as inhibitory or excitatory - -False (neurotransmitters) The action potential is - -A result of the movement of ions Voltage-gated ion channels open when a protein binds to the receptor - -False (they can only open in response to a change in voltage across the plasma membrane) The central nervous system contains: - -Brain and spinal cord Only pre-synaptic neurons are coated with myelin - -False (Only cells in the white matter are coated with myelin) Acetylcholine exocytosed from the presynaptic cell travels to the postsynaptic cell to start the action potential in the postsynaptic cell - -True The resting potential of neurons is: - --60 mV How do the glial cells (i.e., myelin sheath) speed up the firing of neurons? - -Glial cells allow the chemistry of the axon to jump down the axon using the Nodes of Ranvier instead of occurring at every micrometer of length of the axon The cell body refers to the part of the neurons that begin at the dendrites and extend to the axon terminal - -False (the part of the neuron containing the nucleus) List the 4 types of glial cells and list a phrase to describe their function - - 1. Schwann cell- provide insulation around the axon in the PNS ASU ASU 2. Oligodendrocytes- provide insulation around the axon in the CNS 3. Astrocytes- star shaped cells that protect the brain from toxic chemicals 4. Microglia- cells that protect the brain in the cellular immune system The axon from a pre-synaptic cell contacts the axon of another neuron - -False (Contacts the dendrites) Excitatory synapses make the post-synaptic cell less likely to fire - -False (Inhibitory synapses make it less likely) In the motor end plate, the event that is the immediate trigger for exocytosis is: - Calcium ions When the presynaptic cell contacts a muscle cell, the synapse area is called the motor end plate - -True Acetylcholine esterase breaks acetylcholine into muscarinic acid - -False (Breaks into acetic acid & choline) The autonomic nervous system contains the sympathetic and the parasympathetic nervous system - -True The terminal web: - -is a site of exocytosis Fast neurons as described in lecture require cytoplasmic signal transduction to open an ion channel - -False (this would make them slow) The axon hillock in the presynpatic neuron fires based on temporal and spatial summation of inputs - -True The presynaptic cell can be: - -In glands, muscle cells, or neurons The nervous system is made up of: - -Glial cell and neurons A cluster of neurons is called: - -Ganglia The peripheral nervous system contains: - -Neurons and supporting cells What is the importance of a synapse? - -It is where one cell talks to another cell by regulative exocytosis The axon hillock is known as the critical area for the decision to fire an action potential - -True The Na-K-ATPase pump moves how many sodiums and potassiums in and out of the cell? - -3 sodiums out ASU ASU 2 potassiums in Why do neurons undergo a refractory period? - -The short delay prevents the action potential from being triggered backwards The parasympathetic nervous system is triggered to act by exposure to epinephrine - False (sympathetic nervous system is triggered by epinephrine) Insulin is produced by alpha cells - -False (produced by beta cells in the pancreas) Vitamin D causes the parathyroid to inhibit new PTH synthesis - -True Insulin is a ligand - -True Where do fats in the body play a role in the balance between glucose and glycogen? - Glucose turns in fat and glycogen, but if blood glucose falls, fat and glycogen are broken down as an alternative energy source Vitamin D is synthesized from cholesterol - -True When the Sympathetic nervous system is triggered glycogen is broken down to glucose to provide more energy - -True Vitamin D is a hormone - -True The medulla of the adrenal gland produces epinephrine - -True Kidneys are part of the endocrine system - -False (They are part of the excretory system) Hormones can be classified into what 3 groups? - - 1. Peptides/proteins 2. Steroid hormones 3. Amine hormones The pituitary gland is a link between _________ and ____________________? - Nervous system and endocrine glands Posterior pituitary releases oxytocin and antidiuretic hormone (ADH) - -True What are the body's natural painkillers? - -Endorphins and enkephalins What produces thyroxine? - -Thyroid gland Once inside the circulatory system _________ is the molecule that binds oxygen - Hemoglobin ASU ASU Veins and venueles have valves in them, but arteries and arterioles do not - -True The slow flow of blood in the capillaries facilitates release of oxygen - -True The inspiratory and the expiratory reserves make up the total volume in the lungs - False (Makes up the vital capacity) The lungs have increased surface area to increase the movement of oxygen into the circulatory system - -True Tidal breathing causes the incoming air to mix with some older air in the lungs - -True When you inhale which set of muscles uses the least amount of ATP and triggers the parasympathetic nervous system? - -Intercostal muscles (diaphragm) One of the problems with the increased surface area of the lungs is that the _______ could stick to each other causing the lungs to collapse. To get around this the body secretes ________________ into the lungs - -alveoli, surfactant Unlike other epithelia the epithelia that make up the capillaries have holes in them called fenestrations - -True When the ventricles contract blood is pushed out into the artery and the artery stretches because of its elastic layers allowing the blood to continue to flow into the circulatory system while the ventricle is relaxing - -True To prevent back flow of blood in the heart there are ________ - -valves There is a reserve of oxygen in the muscles held by - -Myoglobin The left ventricle of the heart contains more muscle - -True The heart contains two circuits. Name them - -Pulmonary circuit and systemic circuit Surfactants is one of the later components made in the fetus (prior to birth) - -True The atrioventricular node fires after the sinoatrial node - -True There are two factors that cause the release of oxygen from hemoglobin- list them - Drop in pH balance (Bohr's effect) and release of partial oxygen pressure The blood flow slows down in the capillaries because the increased total area of the capillary is very large - -True Red blood cells carry CO2 back to the lungs - -False (Oxy