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Biology Test 5: Chapter 34
Terms in this set (30)
Single Circulation vs. Double Circulation
What is the purpose of the circulatory system?
What are the basic components of a circulatory system?
Set of Interconnecting Vessels
**Open Circulatory System
Circulatory Fluid - Hemolymph
Hemolymph bathes the organs directly [in insects and other arthropods]
From heart to spaces surrounding organs called ....
**Closed Circulatory System
Circulatory Fluid - blood
Can have one or more hearts pump blood through vessels
One-way blood flow
[Annelids, most cephalopods, and ALL vertebrates]
What are the two types of circulatory systems found in vertebrates?
Single Circulation: bony fishes, rays, and sharks
One loop, and then the heart in each circuit
Blood leaving the heart passes two capillary beds before returning
2 chambers, one ventricle and one atrium
Double Circulation: amphibians, reptiles, and mammals
Blood passes through the heart twice
Oxygen poor and oxygen rich blood is pumped separately from the right and left sides of the heart
Double Circulation (Mammals)
*Structural features of heart:
1) Atria: thin walls and serve as a collection chambers for blood returning to the heart
2) Ventricles: more muscular and contract much more forcefully than the atria
Cardiac Output: volume of blood each ventricle pumps per minute
1) Arteries: branch to arterioles and carry blood away from the heart to capillaries
2) Capillary beds: sites of chemical exchange between the blood and interstitial fluid
3) Venules converge to veins and return blood from capillaries to the heart
[NOTE: arteries and veins are distinguished by the direction of blood flow, not by O2 content]
*The Flow of Blood in the Heart - one circuit = goes to the heart twice from atrium to ventricle (2x, right then left)
*Why is it unidirectional? - to keep the flow going without mixture of oxygen-rich and oxygen-poor blood; valves help with this [AV Valve between atrium and ventricle and then the Semilunar Valve for after blood leaves the ventricles to the pulmonary artery or aorta]
*How is the heart rhythmic beat maintained? -
1) Auto-rhythmic: some cardiac muscle cells can contract without any signal from the nervous system
2) SA Node: pacemaker of the heart, setting the rate and timing of the heart beat; signals are sent to the AV node where impulses are delayed and then travel to ventricles to contract [regulated by hormones and temperature]
*What two nodes play a role in the heart's beating? - SA Node, AV Node
Flow of Blood in the Mammalian Heart [Double Circulation ext.]
1) Right Ventricle
2) Lungs through pulmonary arteries
3) Through pulmonary vein to Left Atrium
4) Left Ventricle
5) Blood is pumped through Aorta (either ascending or descending)
6) Exchange of gas in capillaries through diffusion, turning blood oxygen-poor
7) De-Oxygenated blood goes to heart through either the inferior Vena Cava or Superior Vena Cava to the Right Atrium
**What are the major components of vertebrate blood?
Blood: a connective tissue consisting of cells suspended in a liquid matrix called plasma
**What are the relative percentages of each major component in the blood?
Cellular Elements: 45%
**What is the function of each component in vertebrate blood?
White layer = white blood cells
What is coagulation?
blood clotting; the formation of a solid clot from liquid blood
Why is coagulation initiated and what is it initiated by?
initiated by a blood vessel being damaged [injury in the collagen fibers], which exposes NEW proteins that attract platelets, which release clotting factors that aid in the formation of thrombin which leads to the formation of fibrin (the clot)
What happens during the blood clotting process?
1) Clotting Facters
2) Enzymatic Cascade
3) + Prothrombin to make Thrombin
4) + Fibrinogen to make Fibrin
Regulated? - conversion of inactive state to an active state [prothrombin is the inactive state of thrombin, and fibrinogen is that of fibrin]; so..inactive proteins are transferred to active in order to make this fibrin clot; Positive Feedback [promotes production of thrombin] vs. Negative Feedback [promotes production of of anti-thrombin (prothrombin)
Thrombus: a blood clot formed within a blood vessel that can block blood flow
What are the key proteins involved in the process of blood clotting?
Thrombin and Fibrin
Enzymatic Cascade -> prothrombin to thrombin
-> fibrinogen to fibrin
= fibrin clot formation
Mutation in blood clotting
Mutation in the clotting process can cause hemophilia (when people bleed from minor bruising)
Atherosclerosis, heart attack (myocardial infarction, **stroke, hypertension)
Atherosclerosis: caused by the buildup of fatty deposits [plaque] within arteries; as it grows, the artery walls become thick and stiff an the obstruction of the artery increases
Heart Attack/Myocardial Infarction: the death of cardiac muscle tissue resulting from blockage of one or more coronary arteries (which supply oxygen-rich blood to the heart muscle); you can test for a heart attack by checking for enzymes in the blood
What is the purpose of the lungs?
gas exchange, varying among vertebrates that lack gills
What are the key structures of the branching ducts that convey air to the lungs?
An infolding of the body surface, divided into numerous pockets
Used in both open and closed circulatory systems
**What is the role of alveoli?
Air sacs covered by capillaries; diffusion occurs
**What is the connection between alveoli and surfactant?
Surfactants coat the surface of the alveoli
Preterm babies lack surfactant and are vulnerable to respiratory distress syndrome
Alveoli that lack cilia are susceptible to contamination
What is the respiratory pigment?
**What is the purpose of hemoglobin?
What does it contain? How does it work?
Hemoglobin (has 4 subunits) carries oxygen; Cooperative Binding: once one oxygen binds, it is easier for the other 3 to do so
Hemoglobin also assists in preventing harmful changes in blood pH and plays a minor role in CO2
What is the Bohr Shift?
We don't want the pH to lower because it will make the hemoglobin less attracted to oxygen (retains less O2) [Any time you drop the pH, you are able to cause a dissociation of hemoglobin and Oxygen]
CO2 produced during cellular respiration lowers blood pH and decreases the affinity of hemoglobin for O2
The pH will shift during gas exchange from 7.4 to 7.2 to release O2 and get CO2, then bicarbonate [a buffer] is created and slightly increases the pH back to 7.4
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