Lecture 29 Intro to Physiology and the Circulatory System Notes from Pages 852 55 875 88 o Biological form is anatomy Adaptation causes animals to vary from one another Natural selection ensures that the fittest survive o Physiology study of physical and chemical basis of function in living organisms o Cells individual independent units specialized for a particular function o Tissues an aggregation of similar cells having a common function Main types of tissues Epithelial connective muscle nervous o Organs collection of tissues which together perform a specialized function o Organ Systems organs working together in a particular process o Circulatory respiratory immune excretory endocrine nervous and muscular systems This picture illustrates the internal exchange surfaces of complex animals It shows how we rely on the release of waste and the passage of nutrients to our system o Bioenergetics the use the use of energy by organisms Food O2 and water must be transported in Wastes and CO2 must be transported out Understand that diffusion is the major mechanism for the movement of substances in organisms that diffusion rate is a function of surface area and the distance over which diffusion must occur o Diffusion is very slow Its proportional to the square of the distance An example 1 second for 100 nano millimeter Means 100 seconds for that same one to diffuse across 1 mm o Effective diffusion distance for organisms is less than 1 mm o There are two solutions to help diffusion which is Body shape and size Helps keep cells in direct contact with environment and easily exchange materials but is limited to invertebrates Circulatory system Moves fluid between each cell s immediate surroundings and the tissues where exchanges occurs o A flat body is ideal for diffusional exchange because it increases surface area and decreases the distance of diffusion especially for gastro vascular cavities That a circulatory system is required for delivery of nutrients and removal of wastes whenever cells are more than 1 mm from an external surface o The muscular pump of the circulatory system is the heart o For animals with many cell layers a circulatory system helps minimize the distance that substances must diffuse to enter or leave cell Know the difference in structure between open and closed circulatory systems o An open circulatory system is one in which the circulatory fluid bathes the organs directly and most arthropods molluscs have it The key word for open circulatory system is directly When the heart relaxes all the hemolymph is drawn back and the heart valves close as the heart contracts or squeezes Pro have less pressure meaning less energy expenditure o In a closed system one encounters blood Blood is the circulatory fluid that is in the vessels It is different from hemolymph interstitial fluid One or more hearts pump blood into large vessels and then they go into the smaller vessels to get inside the organ s Closed systems consist of earthworms annelids and vertebrates animal with a back bone Pros high blood pressure meaning there is an effective amount of oxygen delivered and nutrients to the cells of larger and more active animals Closed systems are well suited for the delivery of blood to organs Know the meaning of the terms hemolymph interstitial fluid and blood o Circulatory fluid which bathes the body cells The heart pumps hemolymph through the circulatory vessels into the interconnected sinuses or spaces around the organs o Hemolymph in invertebrates with an open circulatory system the body fluid that bathes tissues The body cells and the hemolymph undergo chemical exchange When the heart relaxes hemolymph goes back into the pores o Interstitial fluid is the fluid filing the spaces between cells in most animals o Blood is confined to the vessels A connective tissue with a fluid matrix called plasma in which red blood cells white blood cells and cell fragments called platelets are supported Know that transport in the vertebrate circulatory system is pressure driven and understand the relationship between flow rate pressure and resistance o The circulatory system of humans and other vertebrates is called the cardio vascular system Know the organization of the circulatory systems with two three and four chambered hearts which vertebrate groups have which and how the three and the four chambered hearts increased efficiency of the circulatory system o Single Circulation The blood passes through the heart once the circuit When the ventricle contracts it sends blood to the gills O2 goes in and CO2 goes out of blood When blood passes through a capillary bed there are two total blood pressure drops significantly The drop in blood pressure in the gills limits the rate of blood flow in the rest of the body of the animal When an animal swims it helps alleviate the slow pace of circulation o Double Circulation Amphibians reptiles and mammals have two circuits The right side of the heart delivers oxygen poor blood to the capillary beds Double circulation distributes a vigorous amount of blood to the brain muscles and other organs Higher blood pressure especially higher than single Evolution of the Heart o Two chambers atrium ventricle o Three Chambers left and right atrium one ventricle The ventricle has a little passage that allows about 90 of oxygen poor blood to the right atrium into the pulmocutaneous circuit capillaries in both lungs and skin When amphibians are underwater they shut down the blood flow to the lungs and instead goes to the skin Reptiles have a septum that divides the single ventricle into separate right and left chambers cid 224 allows the flow of blood to the lungs It also shut down the flow of blood when animal is underwater o Four Chambers two atria and two ventricles Mammals and birds Left side Right Side o Receives and pumps only oxygen rich blood o Receives and pumps only oxygen poor blood Require way more energy thus a bigger circulatory system ten times more O2 and fuel to tissues Know the parts of the mammalian heart and the pattern of blood flow in our circulatory system Know the contraction pattern and be able to correctly use the terms diastole and o systole o Systole is when the heart is contracting o Diastole is when the heart is relaxing Chapter 41 Concept 41 1 An animal s diet must supply chemical energy organic molecules and essential nutrients Essential nutrient a substance that an organism cannot synthesize from any other material and therefore must
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