Biology Notes: Chapter 22

Transcription

1 Biology Notes, Chapter 22, page 1 Circulatory system Biology Notes: Chapter 22 I. Functions A. Transport substances 1. Gasses: carbon dioxide, oxygen 2. Wastes from cell 3. Hormones 4. Nutrients to cells 5. Leucocytes (white blood cells) to fight infection B. Controls the internal balance of 1. Water 2. ph 3. Temperature C. Immunity (ability to fight disease, infection) through leucocytes and antigens II. Components of blood A. Percentages 1. 45% solids: erythrocytes, leucocytes, thrombocytes 2. 55% liquid: plasma, hormones, antibodies 3. 92% of all blood is water B. Blood Solids 1. Erythrocytes: red blood cells a. 5.5 million cells per drop b. Disk-like shape with biconcave center c. Have no nucleus d. Survive up to 120 days e. Carries gasses through the presence of hemoglobin (iron and protein molecule that carries oxygen or carbon dioxide) 1) iron gives blood and erythrocytes the red color 2) blood is always red because of the iron, not the oxygen f. Produced in marrow and spleen 2. Leucocytes: white blood cells a. 5,000 to 10,000 cells per drop b. Amorphic (blob-like) shape c. Have nucleus d. Survive two to five days e. Phagocytosis: process whereby leucocytes engulf and digest substances in the blood f. Leucocytes amass in areas of infection. Pus is a collection of dead leucocytes. g. Formed in marrow and spleen 3. Thrombocytes: blood platelets a. 250,000 per drop

2 Biology Notes, Chapter 22, page 2 b. Irregular shapes c. Have nucleus d. They causes coagulation (the formation of a blood clot). Thrombin: blood clot e Formed in the marrow C. Plasma: liquid portion of blood 1. Consists of 90% water and 10% proteins, minerals, nutrients, hormones and wastes 2. Helps in immunity by carrying antibodies to fight antigens a. Antigens: toxic chemical formed by pathogens (disease-causing agents) b. Antibodies: chemicals produced by leucocytes to fight antigens; specific to invading antigen III. Blood Types A. Blood types are dete rmined by positive and negative factors 1. Agglutinogen: positive (accepting) chemical 2. Agglutinin: negative (rejecting) chemical B. Blood typing Acceptable % within Type Agglutinogen Agglutinin Blood Population A A b A & O 41% B B a B & O 10% AB A & B none ALL 4% O none a & b O 45% C. Ph factor 1. Positive blood: has Rh factor 2. Negative blood: does not have Rh factor 3. Erythroblastosis: when the mother's blood attacks the baby's blood because the baby has the Rh factor (from the father) and the mother's blood does not. Therefore the mother's blood treats the baby like an invading body. IV. Problems with blood A. Anemia (low amount of hemoglobin in the blood) 1. Low amount of hemoglobin means a lower red blood count 2. Insufficient oxygen causes low iron, buildup of CO 2 ), possible hemorrhage B. Leukemia: extremely high white blood cell count; form of cancer C. Hemorrhage: excessive bleeding; use direct press on wound or pressure point to try to control bleeding D. Hemophilia: genetic disorder whereas the body cannot clot E. Blood clots in the blood vessels 1. Thrombus: stationary clot 2. Embolus: moving clot; extremely dangerous as it can block blood flow to brain or heart 3. Phlibitus: clots in legs F. Edema: swelling cause by the buildup of fluids (plasma) in tissue

3 Biology Notes, Chapter 22, page 3 V. Heart A. Description 1. hollow, musular organ 2. four chambers 3. About the size of a clenched fist 4. Weighs about 12 oz. 5. Found in a slanted position between the lungs 6. The apex (point) directed toward the left 7. Heart beats 100,800 times pumping 8,000 liters of blood per day B. Structure 1. Pericardium: fibrous, sac that loosely covers and protects the heart a. secretes pericardial fluid into space between pericardium and heart 2. Walls of heart made up of three layers a. epicardium: connective tissue tightly attached to muscular tissue; keeps the muscles from becoming saturated with pericardial fluid b. myocardium: thickest layer; muscle that contracts to pump blood; the pacemaker is a patch of muscular tissue that controls heartbeat rhythm c. endocardium: thin layer of epithelial tissues; prevents the blood from saturating the myocardium 3. Septum: muscular wall that separates right and left sides of the heart 4. Atrium (atria, pl): upper chamber that receives blood and pumps it into ventricle 5. Ventricle: lower chamber that pumps blood into blood vessels of the body 6. Valves are moved by the force of the blood during each heartbeat a. atrioventricular valves: permit passage of blood from atria to the ventricles but prevent a reverse flow --the right AV is a tricuspid --the left AV is a bicuspid b. semilunar valves: permit the flow of blood out of the ventricles into the blood vessels VI. Blood flow through the heart A. Right Atrium 1. The superior vena cava drains deoxygenated blood from body parts above the heart (including the arms) into the right atrium 2. The inferior vena cava returns deoxygenated blood from body regions below the level of the heart 3. As right atrium fills with blood, it contracts, squeezing the blood through the tricuspid valve into the right ventricle B. Right Ventricle 1. Receives blood from right atrium 2. Contracts, closing the tricuspid valve, pushing blood into the pulmonary artery C. Lungs 1. Pulmonary artery divides, each branch leading to a separate lung 2. Blood flows through arteries into the arterioles surrounding alveoli where oxygen is absorbed. 3. The oxygenated blood returns to the heart through the pulmonary veins

4 Biology Notes, Chapter 22, page 4 D. Left Atrium 1. Receives oxygenated blood through pulmonary veins 2. Contract, pushing blood through bicuspid valve into left ventricle E. Left Ventricle 1. Receives oxygenated blood from left atrium 2. Contracts, closing bicuspid valve and opening aortic semilunar valve 3. Blood enters aorta which branches taking blood out to the body VI. Heartbeat and Heart Rate A. Heartbeat (cardiac cycle): one contraction and relaxation of the heart muscle 1. Systole (SIS tuh lee): contraction of heart 2. Diastole (dye AS tuh lee): relaxation of heart 3. Stethoscope: device used to listen to the heart B. Regular rhythm of systole and diastole is controlled by the conduction system of the heart, specialized tissue embedded in the myocardium 1. Sinoatrial node (SA node) starts each systole and sets the heart rate a. has own rhythm of about 80 electrical impulses per minute b. can be increased or decreased by the nervous system c. impulse is transmitted through muscle to both atria so both contract simultaneously 2. Atrioventricular node (AV node) sends impulse to each ventricle causing them to contract C. Electrocardiogram (ECG): recording of the electrical changes that occur in the myocardium during a cardiac cycle; used to detect heart problems D. Heart Rate 1. Typical heart rate of an adult is about 70 beats per minutes. 2. During moderate exercise it's about 120 bpm 3. Above 140 bpm the ventricular diastole is too short for the ventricles to fill. Therefore less blood causes fatigue. VII. Blood vessels A. Arteries: carry blood away from heart; 1. Usually in the deeper muscles, between muscles and bones 2. Pulse: rhythmic force of blood traveling through the arteries 3. Strong, muscular walls have three layers a. Outer elastic layer b. Middle muscular layer c. Inner one-cell-thick layer of epithelial cells 4. Largest artery is the aorta 5. Arteries form smaller vessels called arterioles that branch into capillaries B. Capillaries: microscopic, one-cell-thick walled vessels 1. connects arterioles and venules 2. diffuses oxygen, glucose, hormones, and other essential substances to cells 3. Absorbs waste substances from cells C. Veins: carry blood toward the heart 1. Capillaries merge to form venules which join together to form veins 2. Walls have three layers but the walls are thinner, less elastic, and less muscular

5 Biology Notes, Chapter 22, page 5 3. Most veins possess semilunar valves which prevent reverse blood flow. 4. Skeletal muscle contractions and the valves force the blood toward the heart 5. All veins, except cardiac and pulmonary, drain into the superior and inferior venae cava VIII. Circulation A. Pulmonary circulation: carrying blood from the right ventricle to the lungs for oxygenation then back to the heart entering left atrium 1. About one pint is in pulmonary circulation at one time 2. Requires only a few seconds B. Systemic Circulation: flow of blood from the left ventricle to all parts of the body except the lungs and then back to the right atrium C. Coronary circulation: carries blood into and out of the heart muscle D. Renal circulation: carries blood in and out of the kidneys E. Portal circulation: carries blood from digestive organs to the liver IX. Heart Problems A. Coronary thrombosis: blockage of the coronary arteries by a blood clot B. Coronary atherosclerosis: buildup of fatty tissue in the walls of the coronary arteries decrease blood flow to myocardium; C. Arrhythmia: irregular heartbeat; caused by a birth defect, tumor, coronary thrombosis or certain drugs D. Heart murmur: when the valves of the heart do not close properly E. Fibillation: condition in which the heart quivers vigorously, but does not pump blood F. Hypertension: high blood pressure G. Factors that lead to heart problems 1. high fat diet 2. elevated stress 3. lack of exercise 4. smoking

6 Biology Notes, Chapter 22, page 6 Excretory System I. Urinary System A. Parts 1. Two kidneys 2. Ureters 3. Urinary bladder B. Purpose 1. Remove substances from the blood 2. Form urine 3. Transport urine our of the body II. Kidneys A. Function 1. Remove excess water, toxic waste products (urea and uric acid), and inorganic salts from the blood 2. Form urine 3. Responsible for maintaining water balance of the body 4. Responsible for maintaining blood ph 5. Release the protein erythropoietin which stimulates bone marrow to increase the formation of red blood cells 6. Helps to control blood pressure B. Description 1. Paired, reddish brown, bean-shaped structures about 4 inches long 2. Located in back of body cavity, one on each side of the spine just above the waist 3. Has two distinct areas a. cortex: dark band along the outer border b. inner medulla: divided into 8 to 18 conical masses of tissue termed renal pyramids through which urine is discharged from the kidney 4. Renal pelvis: area in which urine is collected 5. Ureter: tube which extends from renal pelvis to urinary bladder; carries urine away from kidneys C. Nephron: urine-forming units of the kidneys 1. At least 1 million microscopic nephrons per kidney 2. Consists of tubules leading to and exiting from a glomerulus D. Blood Circulation 1. Blood enters the kidneys by renal arteries 2. Arteries subdivide into afferent arterioles that lead into the 30 to 40 capillary loops of the glomerulus. 3. Blood pressure is very high in the arterioles allowing efficient filtering by the nephron 4. Pathways exiting the glomerulus are efferent arterioles that rejoin into veins and exit through the renal hilus E. Urine: liquid waste 1. Urine is usually acidic (ph of 6 or lower) thus preventing bacterial growth 2. Contains 95% water and 5% solid solutes including:

7 Biology Notes, Chapter 22, page 7 a. urea: organic molecule consisting mostly of Nitrogen; formed in liver and carried to kidneys in the bloodstream b. uric acid: combination of ammonia (produced in liver) with hydrogen ions removed from blood to reduce its acidity c. creatinine d. inorganic salts e. urochrome: pigmented product of blood breakdown; gives urine its yellowish color 3. Production: produced in glomerulus a. Arterial blood pressure drives a filtrate of plasma across the capillary walls of the glomeruli into the open space called Bowman's space b. Plasma collects in Bowman's capsule c. About 180 qt of plasma per day is filtered in the glomerula filtrate. III. Ureters A. Description 1. Long smooth muscular tubes that connect the kidneys to the bladder 2. Peristalsis moves urine down into the bladder 3. There is a one-way valve between the bladder and ureter B. Infections occur when urine backs up into the ureters and kidneys because the one-way valves do not work properly IV. Urinary Bladder: hollow sac for the storage and release of urine A. Micturition: the passing of urine from the bladder into the urethra and out of the body B. Steps of Micturition 1. When the bladder is filled with urine, pressure on sensory nerve endings in the bladder wall cause a desire to micturate 2. The sphincter between the urethra and the bladder relaxes due to voluntary or involuntary control 3. Urine is propelled by peristalsis of the bladder wall out of the body V. Kidney Problems A. Congenital abnormalities of size, shape, and number of kidneys are common. These only cause problems if they interfere with the passage of urine. B. Diabetes mellitus: extra blood sugar spills into the urine leading to increased urination and excessive thirst; most common cause of kidney failure C. Uremia: caused by the build-up of toxic wastes in the body due to improper filtration D. Hemolytic uremia syndrome: most common cause of kidney failure in infants; caused by e.coli in the kidneys E. Kidney stones: extremely hard, sharp obstructions in the kidneys and ureters 1. number of different types; most common type is made of calcium salts 2. Cause not completely understood but is related to diet and fluid intake; rarely forms due to kidney infection 3. Treatment: a. time; wait until stones pass from body through urethra b. Lithotriptor: treats large kidney stones by emitting high energy sound waves at the

8 Biology Notes, Chapter 22, page 8 stones; patient sits in warm water; sound pulverizes the stones into small fragments that can be passed through the urine G. Dialysis: separation of dissolved substances, particularly large molecules from smaller ones, using the ability of semi-permeable membranes 1. Hemodialysis: use of dialysis to remove toxic waste products from the blood 2. Artifical kidney machine is an instrument that performs hemodialysis H. Kidney transplants are the best treatment for kidney failure