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An in-depth exploration of the transport and exchange systems in the human body, focusing on the respiratory and cardiovascular functions. The respiratory system moves oxygen into the body and carbon dioxide out, while the cardiovascular system transports various materials throughout the body, including nutrients, hormones, and waste products. The structure and functions of the heart, blood vessels, red and white blood cells, and plasma, as well as the processes of blood clotting and heart attacks.
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Chapter 28 - Transport and Exchange Transport and Exchange Systems of the body Respiratory Moves o 2 into, and CO 2 out of the body Cardiovascular Transports materials to and from all other systems Digestive Transforms food into a form that can be transported throughout the body Urinary Filters bodily fluids, removes waste while conserving water and other materials The Cardiovascular System Fluid transport system Three components: Heart, blood vessels, and blood Transports many different materials throughout the body Nutrients, vitamins, waste products, hormones, immune system cells and proteins, oxygen, CO 2 , heat Centrifugation will separate blood into two layers ~55% plasma 92% water 7% plasma proteins 1% other solutes ~45% formed elements 99.9% red blood cells Red blood cells Most numerous of the formed elements Transport O 2 to and CO 2 from every part of the body .1% white blood cells and platelets White blood cells Critical players in the immune system Platelets Small fragments of cells Important in the blood-clotting process Red blood cells “Erythrocytes” filled with the iron-containing pigment hemoglobin Gives blood its red color Binds to O 2 in the lungs which is required for metabolism Releases O 2 in other body tissues Binds to CO 2 in body tissues produced during metabolism Releases CO 2 in the lungs Present in large concentration 4.8 – 5.4 million per cubic millimeter of blood
~1/3 of all cells in the body Odd structure Lost nucleus and organelles Cannot maintain themselves very well Average life span of 120 days 180 million new RBCs made each minute Cell membrane filled with hemoglobin White Blood Cells “Leukocytes” Possess standard cellular organelles Central to body’s immune system operation 6,000 per cubic millimeter of blood Platelets Fragments of cells Broke away from large cells in bone marrow Enzyme-bearing packets Aid in blood clotting at sites of injury Plasma 92% water Proteins and other materials are dissolved in this water Plasma proteins are most numerous Ex. Antibodies, transport proteins, clotting proteins, etc Non-protein materials are all present Ex. Hormones, nutrients, wastes, ions, etc The Heart Muscular pump Roughly the size of a clenched fist Located near the back of the chest wall directly behind sternum Heart moves blood through blood vessels Blood exits and enters through two circulation loops Pulmonary circulation Picks up O 2 from lungs Systemic circulation Delivers O 2 to other body tissues 4 Chambers 2 associated with pulmonary (right atrium, right ventricle) 2 associated with systemic circulation (left atrium, left ventricle) Pulmonary Circulation Blood enters the right atrium through two veins Superior and inferior vena cava This blood is returning after distributing O 2 throughout the body This blood is deoxygenated (O 2 - poor) Right ventricle pumps blood out of the heart through pulmonary arteries Systemic Circulation Newly oxygenated blood returns to the left atrium
Blood pressure is rather low in veins Skeletal muscles and one-way valves work together to move blood through veins back to the heart Skeletal muscles squeeze blood along Valves prevent backward movement in veins The Respiratory System Breathing has two central functions Capturing and distributing O 2 Without O 2 , out cells lack energy required to function 5 – 6 minutes without breathing generally results in death Disposal of CO 2 CO 2 produced during metabolism must be removed CO 2 disposal also regulates blood pH Components of respiratory system: Nose, nasal cavity, sinuses, pharynx (throat), larynx (voice box), trachea (wind pipe), bronchi and bronchioles (air conducting passageways), lungs Lungs are comprised mainly of grape-like clusters of tiny hollow sacs at the end of each bronchiole “Alveoli” Air exchanging chambers of lungs 300 million present in set of lungs Surface area equivalent to a tennis court Tightly linked with capillary networks Ventilation is the first step in respiration Physical movement of air into and out of the lungs Contraction of the diaphragm decreases the volume of the thoracic cavity Reduces the pressure inside the lungs Air moves into lungs Relaxation of diaphragm increases volume of thoracic cavity Increases pressure inside lungs Air flows from lungs Digestive System Digestive tract is a muscular tube “Alimentary canal” or “gastrointestinal tract” Mouth anus Mouth, tongue, pharynx, esophagus, stomach, small intestine, large intestine Various accessory organs exist along the length of the digestive tract Salivary glands, gall bladder, liver, pancreas Central function is to convert ingested food into a form the body can use These molecules enter the circulatory system and are distributed throughout body Involved in removal of waste remaining after useful materials have been removed Carbohydrates and proteins are broken down into sugars and amino acids
Carbs and amino acids diffuse across inner lining of small intestine into adjacent capillaries Fat digestion is more complicated Large molecules are broken down into small molecules that ultimately enter the cardiovascular system “Tube” has several layers Inner lining is epithelial tissue (“Mucosa”) Next layer is connective tissues Blood vessels and nerves present Nerves coordinate muscular contraction and secretion of digestive juices Next layer has 2 sets of smooth muscle Alternating contractions move food through the digestive tract by peristalsis Outermost layer is connective tissue Numerous folds in mucosa increase surface area available for absorption of digested food Also permit expansion Villi are smaller-scale projections of mucosa Further increase surface area available for absorption Food moves into adjacent capillaries Fats move into lymphatic vessels then blood Steps in Digestion: Mouth Entry place for food Mechanical breakdown by chewing Chemical breakdown of carbs by enzymes secreted by salivary glands Food moved by tongue into pharynx Pharynx Muscles push food to esophagus Esophagus Muscles push food into stomach Stomach Functions in digestion and temporary storage Mechanical digestion by churning food Chemical digestion by digestive juices Mainly protein digestion Glands secrete gastric juice into stomach through gastric pits ~45 ounces of gastric juice per day Contains hydrochloric acid and enzymes Low pH aids in digestion, kills bacteria and other microorganisms Protecting mucus protects cells lining the stomach Few substances pass directly from stomach into circulation Ex. Alcohol, and some drugs After several hours, food is converted into soupy mixture (“Chyme”) A circular muscle regulates flow of chyme into small intestine “Pyloric Sphincter” Small Intestine Small in diameter
Holds and compacts material that is large waste (produces feces) Returns water to general circulation Absorbs vitamins produced by resident bacteria Divided into 3 regions: Cecum Contains pouch called appendix Non-essential arm of immune system Can become infected (“appendicitis”) Colon Longest section of large intestine Rectum Storage site of feces Urinary System Function in elimination of liquid waste Digestive system removed retained waste from digestion Urinary system removes waste generated through cellular activity throughout body Filters waste from blood Passes waste to the urinary bladder for elimination Filters waste from blood Regulates blood volume Controls ion concentrations Maintains pH balance in body Conserves bodily resources Organs in Urinary System: Kidneys Located on either side of vertebral column Shaped like kidney beans About size of small pears Blood arrives via renal arteries Blood exits via renal veins Urine exits via ureters One input, two outputs