Understanding Homeostasis & Nervous System: Regulating Internal Environment & Neurons, Quizzes of Biology

Download Understanding Homeostasis & Nervous System: Regulating Internal Environment & Neurons and more Quizzes Biology in PDF only on Docsity! TERM 1 homeostasis DEFINITION 1 Homeostasis (from Greek: , homoios, "similar"; and , histmi, "standing still"; defined by Walter Bradford Cannon in 1929 + 1932) is the property of a system, either open or closed, that regulates its internal environment and tends to maintain a stable, constant condition. AINT NO POSITIVE FEEDBACK IN HOMEOSTASIS 'COZ THAT BE FOOLS CRAZY THANG TO DO... like.. we'd ripend then spoil like fruit does, which is positive feedback... i guess we do do that but later in metabolism... NOT HOMEOSTASIS THOU coz it c TERM 2 Controlled condition DEFINITION 2 what you want to control, affected by a disturbance ex, BOdy core temperature is coooold mama! TERM 3 sensor DEFINITION 3 asseses the condition ex, Core temperature sensors (i'd think on the skin) say: "oh damn it cold, i better send a shout out ..." TERM 4 sensory signal > integration center DEFINITION 4 the IC makes the comparison bet the sensor and a set point (which is what the condition should be) ex, SS= afferent neurons (signal path) holla at the IC IC= Hypothalamus says "aight, i gotcha, im on it, lemme see whats wrong" ... THEN: see +/- signal TERM 5 +/- error signal DEFINITION 5 measures difference between set point and given condition ex, efferent neurons (signal paths which holla at...) TERM 6 effector DEFINITION 6 structure (organ) that can make the difference ex, the skeletal muscle (after being hollared at) TERM 7 controlling variable DEFINITION 7 what the effector does and how it changes. ex, heat produced by shivering (shivering thermogenesis) TERM 8 neuron DEFINITION 8 A neuron ( , also known as a neurone or nerve cell) is an excitable cell in the nervous system that processes and transmits information by electrochemical signaling. TERM 9 dendrite DEFINITION 9 Dendrites (from Greek dndron, -tree-) are the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project. signal input (received) TERM 10 soma DEFINITION 10 cell body of the neuron TERM 21 direction of ions during AP? DEFINITION 21 from cell bodies (axon hillock) to axon terminals (synaptic terminals). TERM 22 Refractory period DEFINITION 22 Refractory period (physiology), the amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following excitation in the areas of biology, physiology, and cardiology. the "downtime" following an AP when a second AP cannot be initiated. TERM 23 whats the connectiong bet RP and voltage channels? DEFINITION 23 During the resting state, the gated Na+ and K+ channels are closed. Ungated channels maintain the resting potential Many gated ion channels are voltaged, openin/closin according to membrane potentials. When a depolarization (rise on graph) opens a voltage channel the Na+flow into the neuron causes further depolarization...and more Nachannels open leading to an AP. TERM 24 myelination DEFINITION 24 Myelin is a dielectric (electrically insulating) material that forms a layer, the myelin sheath, usually around only the axon of a neuron. TERM 25 chemical synapse DEFINITION 25 Chemical synapses are specialized junctions through which neurons signal to each other and to non-neuronal cells such as those in muscles or glands. TERM 26 Steps of synaptic transmission DEFINITION 26 1) AP depolarizes plasma membrane of the synaptic terminal 2) It opens voltage-gated Ca channels, Ca influx 3) The [hi] of Ca causes the synaptic vesicles containing neurotransmitters to fuse w the presynaptic membrane. 4)Then they release the neurot's into the synaptic cleft 5) the neuro-t binds to a receptors in the postsynaptic membrane which opens channels. 6) the neuro-t is released and the channels close TERM 27 IPSP DEFINITION 27 An inhibitory postsynaptic potential (IPSP) is a synaptic potential that decreases the chance that a future action potential will occur in a postsynaptic neuron or -motoneuron. When the postsynaptic membrane HYPERpolarizes due to the opening of Cl- and K+ channels. They move the membrane potential farther from threshold. TERM 28 EPSP DEFINITION 28 excitatory postsynaptic potential (EPSP) is a temporary DEpolarization of postsynaptic membrane potential caused by the flow of positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels. Bring the membrane potential towards threshold. TERM 29 temporal summation DEFINITION 29 Summation is a method of achieving or inhibiting action potential in the postsynaptic neuron, when one presynaptic neuron does not generate enough neurotransmitter. signal comes in twice from same dendrite terminal branch of presynaptic neuron. TERM 30 spatial summation DEFINITION 30 the combined effect of EPSP and IPSPs are produced nearly simultaneously by different synapses. TERM 31 presynaptic DEFINITION 31 in the axon terminal, before "passing on the message" the neurotransmitters. TERM 32 postsynaptic DEFINITION 32 the part of the dendrite (part of the soma, cell body) which receives the neurotransmitter "the message." TERM 33 autonomic NS DEFINITION 33 The autonomic nervous system (ANS or visceral nervous system) is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. TERM 34 Somatic NS DEFINITION 34 . TERM 35 central NS DEFINITION 35 The central nervous system (CNS) is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of bilaterian animals-that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish. Responsible for integrating information