UH BIOL 1361 - Final Exam Study Guide (14 pages)

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Final Exam Study Guide

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Final Exam Study Guide


This study guide covers the material of Thermoregulation and Homeostasis, Blood Glucose Homeostasis, Osmoregulation, Circulation, Cell Communication and Endocrine System, Neurons, & Reproduction.

Study Guide
University of Houston
Biol 1361 - Intro to Biological Science
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BIOL 1361 1nd Edition Exam 3 Study Guide Lectures 20 26 Lecture 20 November 20 Thermoregulation and Thermoconformity An animal is a regulator for an environmental variable if it uses internal mechanisms to control internal change in the face of external fluctuation An example of this is a river otter An animal is a conformer for a particular variable if it allows its internal condition to change in accordance with external changes An example of this is a bass Behavior and Heat Exchange Endotherms humans and birds are warmed by heat generated by metabolism Ectotherms fish and reptiles and invertebrates gain heat from external resources o Ectotherms adjust their body temperature behaviorally by seeking out shade or laying in the sun o Because their heat source is largely environmental ectotherms generally consume less food than endotherms Circulation and Heat Exchange In response to changing temperatures of their surroundings many animals alter the amount of blood and hence heat flowing between their body core and their skin Nerve signals that relax the muscles of the vessel walls result in vasodilation a widening of superficial blood vessels o As a result of the increase in vessel diameter blood flow in the skin increases o In endotherms vasodilation usually warms the skin and increases the transfer of body heat to the environment by radiation conduction and convection In contrast vasoconstriction reduces blood flow and heat transfer by decreasing the diameter of superficial vessels Counter Current Exchange o In many birds and mammals reducing heat loss from the body relies on countercurrent exchange the transfer of heat between fluids that are flowing in opposite directions o In a countercurrent heat exchanger arteries and veins are located adjacent to each others warm blood moves from the body core in the arteries it transfers heat to the colder blood returning from the extremities in the veins o Because blood flows through the arteries and veins in opposite directions heat is transferred along the entire length of the exchanger maximizing the rate of heat exchange 4 Components of An Animal s Energy Budget o Conduction The direct transfer of thermal motion heat between molecules of objects in contact with each other as when a lizard sits on a hot rock o Convection The transfer of heat by the movement of air or liquid past a surface as when a breeze contributes to heat loss from a lizards dry skin or when blood moves heat from the body core to the extremities Ex fan o Radiation The emission of electromagnetic waves by all objects warmer than absolute zero A lizard absorbs heat radiating from the distant sun and radiates a smaller amount of energy to the surrounding air o Evaporation The removal of heat from the surface of a liquid that is losing some of its molecules as gas Evaporation of water from a lizards moist surfaces that are exposed to the environment has a strong cooling effect Lecture 21 November 12 Regulation of Blood glucose o Glucose absorbed across intestine into the bloodstream o Blood glucose enters the liver and muscle cells o In the cells glucose is polymerized to glycogen o The pancreas secretes insulin when blood glucose rises after eating o The pancreas secretes glucagon when blood glucose drops below set point First green arrow eating First black thick arrow insulin release Second black arrow glucose uptake Third black thick arrow glucagon release Fourth black arrow glucose release and glycogen breakdown Lecture 22 November 17 Osmoregulation Controlling solute concentration and water gain or loss from the body fluids Cell function requires specific and stable solute concentrations Excretory Processes Filtration o 2nd most selectively specific o The body fluid enters the epithelial tubule o Pressure is exerted here o Only small molecules can cross the membrane Reabsorption o 1st most selectively specific o Selective recovery of valuable solutes Glucose Salts Vitamins Amino acids Secretion o Also 1st most selectively specific o Selective transport of ions or other substances into filtrate Excretion o 3rd most selectively specific o The filtrate leaves the body Comparison of the Different Excretory Systems Lecture 23 November 19 3 Structural Arrangements that Minimize Diffusion Distance o Body shape Ex a flattened thin body will allow all cells to be within diffusion distance of external environment o Gastrovascular Cavity In lacking a circulatory system hydras and other cnidarians a central Gastrovascular cavity functions in the distribution of substances throughout the body and in digestion The combination of a Gastrovascular cavity and a flat body is well suited for exchange with the environment o Circulatory System All cells are within diffusion distance of a capillary or sinus Open Circulatory System versus Closed Circulatory System o Open Circulatory System The lower hydrostatic pressures make them less costly in terms of energy expenditure o Closed Circulatory System High blood pressure enables the effective delivery of O2 and nutrients to the cells of larger and more active animals Well suited to regulating the distribution of blood to different organs Arteries vs Veins vs Capillaries o Arteries 3 layers Outer layer consists of THICKER connective tissue and elastin Middle layer consists of THICKER muscle and elastin Inner layer consists of endothelial cells o Veins 3 layers Outer layer consists of THINNER connective tissue and elastin Middle layer consists of THINNERmuscle and elastin Inner layer consists of endothelial cells valve o Capillaries 1 layer 1 layer consists of endothelial cells Blood Flow Rate and Pipe Diameter The smaller the cross section the faster the flow rate The larger the cross section the slower the flow rate Single Loop Circulation System vs Double Loop Circulation System Lecture 24 November 24 Similarities and Differences between Pathways of Local and Long Distance Signaling o Hormones The signaling molecules broadcast throughout the body by the endocrine system are called hormones Different hormones cause distinct effects and only cells that have receptors for a particular hormone respond It takes many seconds for hormones to be released into the bloodstream and carried throughout the body The effects are long lasting because the hormones can remain in the bloodstream for minutes to hours o Nerve Impulses In the nervous system signals called nerve impulses travel to specific target cells along communication lines consisting

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