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53 Cards in this Set
- Front
- Back
Gastrovascular cavities
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bodies being only two cell layers thick, diffusion is optimal in trans-porting nutrients throughout the organism.
Example: cnidarians, platyhelminthes |
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Open circulatory system
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one or more hearts pumps hemolymph into sinuses surrounding organs; body movements squeeze sinuses, assisting in circulating hemolymph
Example: arthropods, most mollusks |
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Closed circulatory system
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one or more hearts pumps blood into vessels which branch into smaller and smaller vessels; blood never leaves the vessels
Example: earthworms, cephalopods, and vertebrates |
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Open v. Closed Circulatory Systems
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Open: requires less energy in operation and maintenance; also, provides support during molting
Closed: more efficient at material transport; most highly developed in vertebrates |
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Vertebrate Circulation - Fish
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1. One ventricle, one atrium
2. Gill & systemic circulation 3. Blood moves slowly 4. Two capillary beds where blood pressure drops |
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Vertebrate Circulation - Amphibians
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1. One ventricle, two atria
2. Pulmocutaneous & systemic circulation 3. Double circulation a. O2 poor blood to lungs, skin b. O2 rich blood to body |
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Vertebrate Circulation - Reptiles
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1. One ventricle, two atria
a. Partial second ventricle 2. Pulmonary & systemic circulation 3. Double circulation a. Less mixing of O2 rich/poor blood |
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Vertebrate Circulation – Mammals, Birds
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1. Two ventricles, two atria
2. Pulmonary & systemic circulation 3. Double circulation a. Left side O2 rich blood b. Right side O2 poor blood 4. Supports endothermicity |
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Cardiac cycle
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one complete cycle of pumping and filling the heart
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Systole
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contraction, pumps blood
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Diastole
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relaxation, fills with blood
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Cardiac output
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volume of blood the left ventricle pumps per min.
a. Avg. stroke volume = 75 mls/contraction b. Avg. cardiac output = 5.25 L/min |
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Atrioventricular (AV) Valves
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located between each atrium & ventricle
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Semilunar valves
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located at two exits of heart (aorta & pulmonary artery)
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Sinoatrial node
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sets rate and timing at which all cardiac muscle cells contract (rt. atrium)
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Atrioventricular (AV) node
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relay which insures the ventricles contract after the atria (0.1 sec - btw. rt. atrium & rt. ventricle)
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Heart murmur
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problem in which blood squirts back through a defective valve
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Three Layers of Vessels
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Outer - connective tissue with elastic fibers
Middle – smooth muscle with elastic fibers Inner – endothelium a. Arteries have thick outer/middle layers b. Capillaries have only endothelium |
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Blood Flow
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As diameter of vessels decreases, velocity of blood flow increases
a. Total cross sectional area of capillaries causes blood flow to decrease - more capillaries than larger vessels |
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Blood pressure
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hydrostatic pressure that blood exerts against the walls of vessels to propel blood
a. Greater in arteries than veins b. Peripheral resistance c. Gravity (neck length) |
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Blood pressure
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Humans – head = 0.35m, 27 mm Hg
Giraffe – head = 2.5 m, 250 mm Hg Dinosaurs – head = 10 m, 760 |
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Blood return
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assisted by rhythmic contractions of smooth muscles in walls of vessels and skeletal muscles squeezing surrounding vessels in limbs
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Capillary function
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blood flow to capillaries is irregular as blood is diverted from one area to another
a. Materials move across capillary walls by exo/endocytosis, osmosis, or through gaps in between cells |
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Blood Composition and Function
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1. Plasma - liquid matrix with cells in suspen-sion (55% blood composition; 90% water)
2. Serum – plasma without clotting factor |
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Plasma Substances
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a. Electrolytes – help maintain osmotic balance of blood; buffer blood to pH 7.4
b. Nutrients c. Proteins d. Hormones e. Respiratory gases f. Metabolic wastes |
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Erythrocytes (RBC’s)
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a. Function: transport O2
b. Small (7 – 8.5 µm in diam.) c. Most numerous (25 trillion/5L) d. Contain hemoglobin (Hb) e. Lack nuclei & mitochondria (mammals); generate ATP by anaerobic metabolism i. 250 million molecules Hb/RBC ii. Each Hb binds 4 molecules O2 iii. Each RBC carries 1 billion molecules O2 |
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Leukocytes (WBC’s)
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a. Function: defend against pathogens
b. Large (10 – 20 µm in diam.) c. 25 - 50 billion/5L (increases during infection) d. Nucleated; 5 different types |
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Platelets
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a. Function: blood clotting
b. Fragments of cells (2 – 3 µm in diam.) c. 750 – 1,750 billion/5L d. Lack nuclei |
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Blood clot
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self-sealing components of blood to stop bleeding; triggered by injuries
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Fibrinogen
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inactive clotting factor
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Fibrin
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active clotting factor
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Platelets
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incorporated to plug bleed
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Thrombus
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formation of a clot inside blood vessels in absences of injury
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Embolus
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traveling clot
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Hemophilia
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genetic mutation that effects any step of the clotting process resulting in excessive bleeding from even minor injuries
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Pluripotent stem cells
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source from which cellular elements develop
a. Ability to differentiate into any blood cell type b. Found in marrow of ribs, vertebrae, sternum, and pelvis |
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Erythropoietin (EPO)
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hormone which stimulates the production of RBC’s
a. RBC’s turn over every 3 – 4 months b. Reduction in O2 triggers EPO synthesis (negative feedback mechanism) c. Alternative to steroids |
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Leukemia
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cancerous line of stem cells that overproduce WBC’s
a. RBC stem cells are crowded out b. Treatment: destroying bone marrow and restocking it with noncancerous stem cells (30 cells required to repopulate) |
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Cardiovascular disease
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disorders of heart and blood vessels; accounts for ½ of all US deaths
Causes: Genetics, Smoking, Sedentary lifestyle, High animal fat diet, High cholesterol |
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Artherosclerosis
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hardening/narrowing of arteries
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Hypertension
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high blood pressure
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Heart attack
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death of cardiac tissue due to prolonged blockage of one or more coronary arteries
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Stroke
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death of nervous tissue due to blockage/rupture of one or more arteries in the head
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Gas exchange
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uptake of O2 from and dis-charge of CO2 into the environment
1. Supports ATP production during respiration 2. Water (aquatic animals) and air (terrestrial animals) are sources of oxygen |
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Respiratory medium
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O2 (oxygen)
1. Higher concentration of O2 in air than water - molecules diffuse more easily through air than water (less energy required) |
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Respiratory Surface
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1. Thin and moist with a large surface area
2. Gas exchange occurs by diffusion 3. Larger in endotherms than ectotherms due to metabolic activity |
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Gills
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out-foldings of the body’s surface, suspended in water
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Ventilation
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aquatic organism’s increase of water flow over the gills
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Countercurrent exchange
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opposite flow of blood in gills to direction of water passing over gills
a. Removes 80% of O2 from H2O b. Dumps CO2 at same time |
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Trachea
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branching system of air tubes throughout an insect’s body
a. Finest branches extend to almost every cell b. Efficient in small insects, but larger insects must ventilate c. Trachea open to outside |
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Lungs
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restricted to a specific region, using the circulatory system to expand functions
a. Found in spiders, terrestrial snails, and ter-restrial vertebrates |
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Breathing
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alternate inhalation/exhalation of air; ventilates lungs
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Diaphragm
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sheet of skeletal muscle that increases lung volume when contracted
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