Chapter 24 Lecture Outline Enger, E. D., Ross, F. C., & Bailey, D. B. (2012). Concepts in biology (14th ed.). New York: McGraw- Hill. 1 24-1
Exchanging Materials: Basic Principles Large, multicellular organisms need a way to deliver oxygen and nutrients to the cells deep within tissues. Several organ systems help deliver oxygen, nutrients to and remove wastes from cells. Circulatory, lymphatic, respiratory, digestive, and excretory systems 24-2
The Cardiovascular System 24-3 Pumps blood around the body Consists of Blood Fluid tissue that transports materials and heat The heart A muscular pump that forces fluid through the body Vessels Pipes that move blood through the body Arteries carry blood from the heart to the tissues. Capillaries are small vessels that carry blood through tissues. Veins carry blood from the tissues to the heart.
The Nature of Blood Consists of Several types of cells Called the formed elements Plasma Contains different kinds of dissolved molecules 24-4
Formed Elements Red blood cells Lack a nucleus Contain hemoglobin Transport oxygen and carbon dioxide Carbonic anhydrase converts carbon dioxide to bicarbonate that can be dissolved in the blood. Anemia is a lack of oxygen resulting from a lack of red blood cells. 24-5
Formed Elements White blood cells Also called leukocytes Lack hemoglobin Have a nucleus Include basophils, eosinophils, neutrophils, lymphocytes, and monocytes Defend the body against microorganisms, damaging chemicals, and cancer 24-6
Formed Elements Platelets Not whole cells Fragments of white blood cells Important in blood clotting Collect at the site of a wound Release clotting factors Initiate a sequence of reactions that trap blood cells to form a clot Eventually the clots (scabs) are replaced by healthy, living tissue. 24-7
Plasma Liquid part of the blood Contains Salts that serve to Buffer and maintain blood ph Maintain osmotic balance Keeps the tissue fluid between cells at the right solute concentration so that it flows into the capillaries, maintaining blood pressure 24-8
Plasma Proteins Antibodies and other immune proteins Albumin to maintain osmotic balance Transports bilirubin from degraded RBCs to the liver Accumulated bilirubin can cause jaundice Nutrients Amino acids Sugars Lipoproteins carry fats and cholesterol Hormones 24-9
Composition of Blood 24-10
Functions of Blood 24-11 Transports molecules, cells Oxygen, carbon dioxide Nutrients Waste products Immune cells and antibodies Hormones Regulates temperature If body temperature is too high, blood will be shunted to the body surface to radiate heat. If body temperature is too low, blood will be shunted to the body core to conserve heat.
The Heart Pumps the blood Generates the pressure necessary to move blood through vessels Blood must flow to move nutrients to tissues and waste away from tissues. Heart must repeatedly contract in order to keep blood moving. 24-12
Mammalian Heart Has four chambers with four valves Two atria and two ventricles Ventricles Are larger and more muscular Force blood through the arteries to the body The aorta and pulmonary artery flow out of the ventricles. Atria Are smaller with thinner walls Pump blood into the ventricles 24-13
Mammalian Heart 24-14 Atria and ventricles are separated by atrioventricular valves. Valves ensure that the blood only flows in one direction. Semilunar valves in the aorta and pulmonary arteries Act as check valves to prevent blood from flowing back into the ventricles when they relax Damaged valves causes inefficient pumping. Detected as heart murmurs because some of the blood is being pushed backward
The Anatomy of the Heart 24-15
Mammalian Heart 24-16 Two different sides have different jobs The right atrium receives blood from the body. The right ventricle pumps the blood to the lungs. Called pulmonary circulation Allows for the exchange of carbon dioxide and oxygen in the lungs The left atrium receives blood from the lungs. The left ventricle pumps blood to all other parts of the body. Called systemic circulation Allows for the delivery of oxygen, nutrient, and waste exchange in the tissues
Pulmonary and Systemic Circulation 24-17
Blood Vessels The tubes that transport blood from one place to another in the body Types of blood vessels Arteries Veins Capillaries 24-18
Arteries Carry blood away from the heart Contraction of the ventricles increases the pressure in the arteries. Called systolic blood pressure Relaxation of the ventricles decreases the pressure in the arteries. Called diastolic blood pressure 24-19
Arteries Blood pressure readings include both types of blood pressure. Systolic/diastolic 120/80 Have thick, muscular, and elastic walls Can stretch when pressure increases Branch into arterioles to take blood throughout the body 24-20
Veins Collect blood from the capillaries and return it to the heart Have very low pressure Walls not very muscular 24-21
Veins Have valves to prevent backflow Dysfunctional valves cause varicose veins. Contraction of leg muscles aids in pushing blood through veins. Sitting or standing for a long time can cause pooling of blood in the feet. Causes swelling Can cause fainting because the brain doesn t get enough blood 24-22
The Structure of Arteries, Veins, and Capillaries 24-23
Capillaries 24-24 Tiny vessels, one-cell thick RBC go through capillaries single file Have thin walls Only one-cell thick Allows materials to diffuse into and out of the blood Allows liquid to be exchanged between the blood and tissue fluid Are numerous All cells in the body have a capillary nearby. Flow of blood through capillaries is slow Allows time for diffusion and fluid exchange
Capillaries 24-25
The Lymphatic System 24-26 A second circulatory system A collection of thin-walled vessels Called lymph vessels Branch throughout body and lymph organs Functions Moves fat from digestive system to blood stream Transports excess fluid back to cardiovascular system Carries immune cells
The Lymphatic System 24-27
The Lymphatic System Lymph Fluid tissue that is moved through the lymph organs via lymph vessels Emptied into large veins near the heart Moved through lymph vessels by muscle contraction Edema Accumulation of fluid in tissues 24-28
Lymph Organs 24-29 Lymph nodes Filter lymph Contain large numbers of white blood cells Remove microorganisms and foreign particles from the lymph When an infection is active, the lymph nodes enlarge Tonsils Near the throat Contain the tonsils and the adenoids Filter pathogens that enter through the mouth and nose
Lymph Organs 24-30 Spleen Contains a large number of white blood cells Filters the blood Cleans out pathogens and dying RBCs Located just below the diaphragm Thymus Produces WBCs called T-lymphocytes Most active in children Shrinks as one ages
Lymph Organs Red bone marrow Found in children s bones Reduced in adult bones Produces RBCs, WBCs, and platelets 24-31
The Respiratory System 24-32 Moves air into and out of the body Lungs Allow gas exchange between air and blood Trachea A tube that carries air into and out of the lung Branches into bronchi then into bronchioles Bronchioles end in alveoli Alveoli are small sacs where gas exchange takes place Air-transport pathway Includes the nose, mouth, and throat Pulls air into the trachea
Respiratory Anatomy 24-33
Breathing System Regulation 24-34 Breathing is the process of moving air into and out of the lungs. Involves the diaphragm A large muscle that separates the chest cavity (containing lungs) from the abdominal cavity When contracted, the diaphragm moves down Creates negative pressure in the chest cavity Pulls air into the lungs When relaxed, the diaphragm resumes its normal position Generates positive pressure in the chest cavity Pushes air out of the lungs
Breathing Movements 24-35
Breathing During Exercise Exercise increases the body s demand for oxygen. Requires faster gas exchange in lungs Accomplished by Increased breathing rate Can involve greater diaphragm contraction to pull in more air 24-36
Breathing During Exercise Can also involve contraction of abdominal muscles to fully empty the lungs This happens when carbon dioxide concentration increases in the blood and blood ph. Sensed by brain, then brain causes increased contraction of the diaphragm and intercostal muscles Increased air exchange volume in each breath 24-37
The Control of Breathing Rate 24-38
Lung Function 24-39 Lungs are specialized so that blood and air can come very close together. This facilitates gas exchange between them. Blood flows through capillaries in the lungs that come very close to the air in the alveoli. Oxygen and carbon dioxide cross the alveoli and capillary walls. Therefore, the surface area of the alveoli must be very large (collectively). This is why there are so many alveoli.
The Association of Capillaries with Alveoli 24-40
Lung Function Gas exchange is facilitated by blood and air movement. Blood enters the lungs high in carbon dioxide and low in oxygen. Air enters the lungs high in oxygen and low in carbon dioxide. Therefore, carbon dioxide diffuses from the blood to the air and oxygen diffuses from the air to the blood. 24-41
Disrupting Lung Function Interfering with blood flow or gas exchange will reduce the efficiency of the organism. A poorly pumping heart reduces the amount of blood that is sent to the lungs. Constriction of bronchioles (asthma) reduces the amount of air that can enter the alveoli. Reducing the number of alveoli (emphysema) reduces the surface area for gas exchange. 24-42
The Digestive System 24-43 Responsible for processing and distributing nutrients Mechanical processing Chemical processing Nutrient uptake Chemical alteration Consists of A muscular tube Glands that secrete digestive juices
The Digestive System 24-44
Mechanical and Chemical Processing The process of taking large pieces of food and breaking them down into individual molecules that can be absorbed Mechanical processing Chewing in the oral cavity generates a food bolus. Increases surface area of food Allows digestive enzymes greater access to the food 24-45
Mechanical and Chemical Processing Salivary glands produce saliva containing some digestive enzymes. Chewing mixes the food with the saliva. Salivary amylase begins to break down starch. Tongue Tastes food Pushes food back toward throat 24-46
Mechanical and Chemical Processing 24-47 Food bolus passes through the esophagus to the stomach Moves from mouth to the pharynx into the esophagus Contractions of the pharynx move the food toward the stomach. In the stomach, food is churned. Mixes food with digestive juices Pepsin breaks down proteins. Low ph denatures proteins The food then moves to the small intestine where chemical breakdown is completed.
Mechanical and Chemical Processing 24-48 Chemical processing in the small intestine Also known as the duodenum Receives digestive enzymes and bicarbonate ions from the pancreas Digestive enzymes complete the chemical processing of food. Bicarbonate neutralizes the low ph of the food coming from the stomach. Receives bile from the liver by way of the gall bladder Emulsifies fat into smaller fat globules Allows digestive enzymes greater access to the fats
Mechanical and Chemical Processing Finally, the remainder of the undigested food passes from the small intestine to the large intestine (colon). 1.5 meters long Water is reabsorbed. Contains bacteria that utilize the undigested food These bacteria produce vitamins that we need. 24-49
Digestive Enzymes 24-50
Nutrient Uptake Once food is broken down into individual macromolecules, they can be absorbed into the bloodstream. Absorption occurs through the lining of the small intestine. Requires a large surface area The small intestine is very long (6 to 8 meters). The lining of the small intestine has fingerlike projections called villi. 24-51
Nutrient Uptake Each villus contains Several capillaries A lymphatic vessel called a lacteal Involves diffusion Water and small ions move into blood via simple diffusion. Sugars and amino acids move into blood via carrier proteins. Fatty acids and glycerol enter intestinal cells where they are built into fats and transported into the lacteals. 24-52
Chemical Alterations: The Role of the Liver The nutrient-rich blood leaves the intestine and goes straight to the liver. Moves through the hepatic portal vein In the liver Enzymes modify the nutrient molecules. Foreign organisms are filtered out. 24-53
Chemical Alterations: The Role of the Liver Toxic substances are detoxified Ethyl alcohol Plant toxins Excess glucose is collected and stored as glycogen. Excess amino acids are converted to Other types of amino acids Glucose and stored Urea and sent to the kidneys 24-54
The Excretory System (The Urinary System) 24-55 Responsible for the processing and elimination of metabolic waste Urea Toxic substances Hydrogen ions Water Salts Consists of Kidneys Ureters Urinary bladder Urethra
The Urinary System 24-56
Kidney Structure 24-57
Kidney Function In order to filter out waste, kidney must have a close association with bloodstream Exchange of waste occurs across a surface Requires large surface area Glomerulus represents a large surface area 24-58
Kidney Function Major activities in kidney Filtration Blood enters glomerulus under pressure as the heart contracts. Glomerular capillaries are porous. Glucose, amino acids, ions, and water are pushed through the pores into the nephron tubules. 24-59
Kidney Function 24-60 Reabsorption Not everything that is filtered into the nephron needs to be excreted. Some molecules are reabsorbed into capillaries around the nephron. Amino acids, glucose, sodium Occurs mostly in the proximal convoluted tubule Water is reabsorbed in the Loop of Henle. Occurs because of osmotic gradients that exist in the kidney Concentrates the urine and conserves water
Kidney Function Secretion Additional waste is moved from the capillaries around the nephron into the distal convoluted tubule. 24-61
Specific Functions of the Nephron 24-62