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29 Cards in this Set
- Front
- Back
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Energy Metabolism
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the sum of processes by which animals acquire energy, channel energy into useful function, and dissipate enegy from their bodies and thus including catabolic and anabolic processes
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energy
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is the capacity to increase order
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Why do animals require energy from the outside? which law of thermodynamics can back it up?
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energy from outside sources is necessary to maintainessential internal
The second law of thermodynamics will suggest that energy input will increase transformation (random motions) |
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The 4 various forms of Energy? Be specific? Which are the two that are important to the animal
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Chemical energy ( created or liberated by the rearranging atoms into new compound configurations
electrical energy- energy a system gets by seperaTing charges Mechanical energy - organized motion molecular kinectic energy- random atomic molecular motion this all vary in their capacity to physiological work |
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What is physiological work? Amd what form of energy can not be used to do physiological work
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is any process carreid out by an animal to increase order. molecular kinectic energy can not be used
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(T/f) all energy used by an animal whether it be internal work or external work generate heat
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True
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Why do animals need to obtain energy regularly thoughout their lives?
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Heat energy can not be recycled so as an animal injest food and most is being discipated through heat which is useless in doing physiological work
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What is definition of an animals metabolic rate?
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an animal either releases enegy as chemical energy, heat and, external work the energy that is released as heat is said to be consumed or exhausted because it can not be used again in a physiological manner the rate at which an animal consumes energy is the metabolic rate
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(t/f) an animals metabolic rate is one of the most important determinants of how much food it needs
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True
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What is SPecific dynamic action (SDA), calorigenic effect or heat increment of feeding
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the increase and metabolic rate caused by food injestion
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What is DIT
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the long term increase in metabolic rate induced by persistent overeating
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Compare and contrast the roles of nervous and endocrine systems in controlling physiological processes
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a. Nervous system control is extremely rapid (milliseconds to seconds), whereas
endocrine control takes minutes to days to bring about its effects. b. Nervous system communication is via electro-chemical impulses, whereas the endocrine system uses blood-borne chemical “messengers” (hormones). c. The nervous system controls short-term processes, such as stimulation of muscle contraction and glandular secretion, whereas the endocrine system controls processes that go on for long periods of time (sometimes continuously), such as growth and maturation, metabolism, and the functioning of the reproductive system. |
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Describe how myelin affects the propagation of action potentials
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In myelinated neurons the only uninsulate, exposed portion of the neuron is the
Nodes of Ranvier. These are the only sites where the membrane can depolarize to threshold and generate action potentials. Thus, conduction along myelinated axons appear to jump from to jump from node to node, a process called saltatory conduction. |
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compare and contrast the roles that electrical and chemical synapses play in nervous system function
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Chemical synapses
Chemical synapses are specialized junctions through which the cells of the nervous system signal to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow the neurons of the central nervous system to form interconnected neural circuits. They thus are crucial to the biological computations that underlie perception and thought. They provide the means through which the nervous system connects to and regulates the other systems of the body. In a chemical synapse, the process of signal transmission is as follows: When an action potential reaches the axon terminal, it opens voltage-gated calcium channels, allowing calcium ions to enter the terminal. Calcium causes vesicles filled with neurotransmitter molecules to fuse with the membrane, releasing their contents into the synaptic cleft, a narrow space between cells. The neurotransmitters diffuse across the synaptic cleft and activate receptors on the postsynaptic neuron (that is, the neuron receiving the signal). Electric synapses While most neurons rely on chemical synapses, some neurons also communicate via electrical synapses. An electrical synapse is a mechanically and electrically conductive link that is formed at a narrow gap between two abutting neurons, which is known as a gap junction. In contrast to chemical synapses, the postsynaptic potential in electrical synapses is not caused by the opening of ion channels by chemical transmitters, but by direct electrical coupling of the neurons. Electrical synapses are therefore faster and more reliable than chemical synapses. Many cold-blooded fishes contain a large number of electrical synapses, which suggests that they may be an adaptation to low temperatures: the lowered rate of cellular metabolism in the cold reduces the rate of impulse transmission across chemical synapses. |
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what are the two major two types of postsynaptic receptors? how do they differ in terms of how they affect postsynaptic neuron function
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a. Ionotropic receptors (direct gated or ligand-gated channels)
i. More prevalent, very rapid, and used in the majority of chemical synapses ii. Single macromolecule forms receptors and ion channel pathway iii. Transmitter binding opens the channel with conformational changes iv. General scheme for synaptic transmission: action potential in presynaptic terminal calcium influx via voltage gated calcium channels release of neurotransmitter by exocytosis binding of transmitter by postsynaptic receptors activation of ligand-gated ion channels ionic current in postsynaptic terminal (an excitatory ionic current would generate a postsynaptic action potential) v. Example: neuromuscular junctions (see below) b. Metabotropic receptors (indirectly gated channels) i. Receptor is distinct from the ion channel it regulates ii. Slower response iii. Neurotransmitter binding second messenger cascade channel gating iv. Examples: G-protein coupled receptors (alters metabolism in cell to affect activity of proteins) and tyrosine kinease receptors (bind growth factor phosphorylation changes signaling) |
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how do invertebrate neural circuits differ from vertebrate neural circuits
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an invertebrae neural will have a uniquely identified neuron where its properties are distinctive, and also this type of invertebrae have individuals neurons (antropods and mollucs) while the verterbrae neuron function in groups
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How many neural synapses are necessary for the stretch reflex to occur
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skeletal muscles are involved in is supplied by 300 neurons
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How does calcium play a role in influencing synaptic transmission and muscle activation
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Excitation-contraction coupling (ECC) is the process whereby an action potential triggers a myocyte to contract. When a myocyte is depolarized by an action potential, calcium ions enter the cell during phase 2 of the action potential through L-type calcium channels located on the sarcolemma. This calcium triggers a subsequent release of calcium that is stored in the sarcoplasmic reticulum (SR) through calcium-release channels ("ryanodine receptors"). Calcium released by the SR increases the intracellular calcium concentration from about 10-7 to 10-5 M. The free calcium binds to troponin-C (TN-C) that is part of the regulatory complex attached to the thin filaments. When calcium binds to the TN-C, this induces a conformational change in the regulatory complex such that troponin-I (TN-I) exposes a site on the actin molecule that is able to bind to the myosin ATPase located on the myosin head. This binding results in ATP hydrolysis that supplies energy for a conformational change to occur in the actin-myosin complex
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what part of the brain acts as an interface between the neuronal and endocrine system? how does it do this?
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the two ways the hypothalamus interfaces the nervous system and the endocrine system: 1) Direct neural release of endocrine hormones in the posterior pituitary.
2)Chemical signalling of the anterior pituitary to release hormones. The first part of the pituitary we'll discuss is the posterior pituitary. It is actually a direct extension of the hypothalamus, in fact, the two are one in the same. Neurons from the hypothalamus send their axons down into the posterior pituitary where they release their neurotransmitters (which are hormones!) into the general circulation. Thus, there's a direct neural-endocrine interface here. Nerves from the hypothalamus release endocrine hormones! The hormones released here (there's two of them) control things such as water regulation in the kidney and uterine contractions in those people so equipped. The other half of the pituitary, the anterior pituitary, has a wide range of functions. It two takes its orders from the hypothalamus, but it does so in a rather different way. There's a special set of blood vessels connecting the hypothalamus and the pituitary. When the hypothalamus wants to signal the anterior pituitary to do something, it releases a specific neurotransmitter into these blood vessels, where they travel to the pituitary and are picked up by cells. In response, these cells release their own special hormones into the general circulation, which travel to the various organs in the body and control endocrine function. There's many roles of the hormones here, including growth, sexual development, metabolism, and quite a few others as well. |
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provide an example of a hormone that acts synergistically to influence the production of a different hormone
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in the HPA pathway vp acts together with CRH to increase the secretion of acth from the anterior pituitary .
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how does negative feedback hormones help to regulate blood glucose levels
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a hormone controlled by a particular pathway causes changes that tend to suppress its own secretion
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are there endotherms that are mpt homeotherms? or that they do not thermoregulate
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An animal that maintains a
constant body temperature. • Generally, an animal that relies upon internal heat generating mechanisms to regulate body temperature (Endothermy)The following graph shows two mammals (endotherms) that occur in hot, desert conditions. The antelope ground squirrel is a small mammal (a ground squirrel); the dromedary (a kind of camel) is much larger. Note that both species allow their body temperatures to increase and decrease during the course of a day; they do not perfectly regulate. The dromedary, being large, heats and cools relatively slowly because of its low SA/V, so it heats gradually over the course of the day, then cools as the temperature cools. The antelope ground squirrel heats up much more rapidly. It will be active and let its body temperature increase until it approaches a temperature that would be lethal; then it quickly returns to its burrow, which is cool, and cools down. It repeats this a number of times during the day; that's why the graph has spikes of temperature increase. |
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are there ectotherms that thermoregulate are poikilotherms always ectotherms
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Some poikilotherms can adjust the enzymes produced under different conditions to adjust to seasonal change in conditions. Physiological change in response to living in new conditions for some abiotic factor is called acclimation. Ectothermic homeotherms can modify their body temperature behaviorally. For example, orienting toward the sun can increase radiation and heat up the body. Allowing a wind or water current to pass over the body could increase heat loss through convection. Lying on a warm surface could increase heat gain through conduction. Experimental evidence indicates that homeothermic ectotherms do have a preference for a particular body temperature: given a choice they will select a particular temperature to be in
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give an example of a mammel that is hypothesized to cool down using a mechanism other than panting or sweating now give an example of a non mammalian endotherm that can cool down without sweating or panting
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The antelope ground squirrel is a small mammal (a ground squirrel); the dromedary (a kind of camel) is much larger. Note that both species allow their body temperatures to increase and decrease during the course of a day; they do not perfectly regulate. The dromedary, being large, heats and cools relatively slowly because of its low SA/V, so it heats gradually over the course of the day, then cools as the temperature cools. The antelope ground squirrel heats up much more rapidly. It will be active and let its body temperature increase until it approaches a temperature that would be lethal; then it quickly returns to its burrow, which is cool, and cools down. It repeats this a number of times during the day; that's why the graph has spikes of temperature increase.
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what is the molecular mechanism by which ectotherms can partial acclimate to a changed ambient temperature
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Alteration in enzyme activity: This can occur through two mechanisms…independently or together
i) A change in the molecular structure of the enzyme…production of different isozymes ii) A change in the concentration of enzymes 2) Alteration in the Fluidity (Viscosity) of Biological Membranes…Homeoviscous Adaptation …….Stabilization of Membrane Function i) Changing the degree to which membrane lipids are saturated…more unsaturated lipids….greater fluidity ii) Altering the concentration of cholesterol in the membrane… cholesterol….increased fluidity |
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in class we have discussed how enzymes can be specialized to operate optimially at specific temperatures what other types of cellular structures can be specialized in such a way
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takes place in normal fat stores, or in specialized
highly vascularized adipose tissue called brown fat (brown because of extremely high mitochondrial content…found in neck and shoulder regions). |
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describe ways that endotherms can thermoregulate without increasing their metabolic rate
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Increase blood
flow to skin • Piloerection – Goose bumps • Change position relative to sun |
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explain away the seeming paradox that the temperature above the TMZ endotherms increase metabolic rate to get rid of heat
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When heat production exceeds heat dissipation, thermal energy is stored in the body and the body temperature rises (hyperthermia). On the other hand, when more heat is transferred to the environment than can be produced or absorbed, the body temperature falls (hypothermia).
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which has the highest mass specific metabolic rate an endotherm in its typical environment or an ecotherm what happens when measured at 37
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Endotherms (of a given size) have much higher metabolic rates than do ectotherms of an
equivalent size (thus larger "a" by about 10 times on average!). A huge difference, but when comparing at 37 celcius they aare about the same |
