Questions and Answers
What is a gastrovascular cavity? In what organisms are these typically found?
A gastrovascular cavity is a central cavity with a single opening in the body of certain animals, including cnidarians and flatworms, that functions in both digestion and distribution of nutrients. They are typically found in hydras, jellies, and other cnidarians.
What are the main components of a circulatory system?
A circulatory fluid, a set of interconnecting vessels, and a muscular pump.
Compare and contrast an open circulatory system and a closed circulatory system.
What is the basic organization of a circulatory system?
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What type of animals have single circulation? Describe this type of circulation.
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What type of animals have double circulation? Describe this type of circulation in mammals.
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Describe double circulation in amphibians.
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Describe the coordinated cycles of heart contraction in mammals.
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Describe the cardiac cycle and cardiac output.
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How is heart rhythm controlled? How does this look in an EKG/ECG?
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Describe the pacemaker of the heart. How is it regulated by hormones?
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Compare and contrast the structure of an artery and a vein.
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What are the changes in blood pressure that occur during the cardiac cycle?
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How is blood pressure regulated?
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What mechanisms help blood flow combat gravity?
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What are the functions of capillaries?
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What is the goal of the lymphatic system? How does it accomplish this?
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What is the role of plasma in blood? What percentage of blood does it comprise?
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What are the major cellular elements of blood? What percentage of blood do they comprise?
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Describe sickle-cell disease and how it impairs the function of the circulatory system.
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What are the respiratory adaptations of diving mammals?
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If carbon dioxide is a product of respiration, how does the body get rid of it? Describe the Bohr shift.
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Describe how blood clots.
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In order to understand cardiovascular disease, describe the role of cholesterol and LDL/HDL in disease progression.
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What are some of the results of cardiovascular disease?
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What are some different respiratory surfaces in organisms?
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How are lungs adapted for gas exchange?
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How do mammals breathe and ventilate the lungs?
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Define tidal volume, vital capacity, and residual volume.
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Describe the control of breathing in humans.
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Study Notes
Gastrovascular Cavity
- Central cavity with a single opening for digestion and nutrient distribution found in cnidarians and flatworms.
- Commonly seen in hydras and jellies.
Components of Circulatory System
- Composed of a circulatory fluid, interconnected vessels, and a muscular pump.
Open vs Closed Circulatory System
- Open circulatory systems have fluid (hemolymph) freely circulating through body cavities; closed systems have blood confined to vessels.
- Closed systems are generally more efficient for nutrient and gas transport.
Organization of Circulatory System
- Includes the cardiovascular and lymphatic systems; the cardiovascular system comprises the heart, arteries, capillaries, and veins.
- The heart propels blood throughout the body tissues.
Single Circulation in Animals
- Present in sharks, rays, and bony fishes; consists of a single pump and circuit.
- Blood moves from gas exchange sites to body tissues before returning to the heart.
Double Circulation in Mammals
- Involves pulmonary (lungs) and systemic (body) circuits; blood passes through the heart twice in each complete circuit.
Double Circulation in Amphibians
- Frogs have a three-chambered heart (two atria, one ventricle) facilitating a forked path for two circuits.
- Blood flow to lungs is restricted when underwater.
Heart Contraction in Mammals
- Right ventricle pumps blood to lungs; oxygen-rich blood returns to the left atrium.
- Left ventricle pumps oxygenated blood to body tissues via the aorta.
Cardiac Cycle and Output
- Alternating contraction and relaxation of the heart; cardiac output is the blood volume pumped per minute by each ventricle.
Heart Rhythm Control
- Certain cardiac muscle cells are self-excitable; the sinoatrial (SA) node regulates cardiac contractions.
- Electrocardiogram (ECG) records electrical impulses during the cardiac cycle.
Pacemaker Regulation
- Regulated by the sympathetic (accelerates) and parasympathetic (slows) nervous systems.
- Hormones like epinephrine also influence pacemaker activity.
Arteries vs Veins Structure
- Arteries have thicker, elastic walls to withstand high pressure; veins contain valves to prevent backflow.
Changes in Blood Pressure
- Systolic pressure is highest during heart contraction; diastolic pressure is the lower pressure during relaxation.
- Arteries remain pressurized, allowing continuous blood flow.
Blood Pressure Regulation
- Controlled by altering arteriole diameter; vasoconstriction increases pressure, vasodilation decreases it.
Mechanisms Against Gravity in Blood Flow
- Fainting response assists blood return to the heart; vein valves prevent backflow.
- Skeletal muscle contraction enhances venous return.
Capillary Functions
- Capillaries facilitate gas, nutrient, and waste exchange between blood and interstitial fluid.
Lymphatic System Goals
- Returns fluids, proteins, and cells to the blood; lymph is circulated via valves and vessel contractions.
Plasma and Blood Composition
- Plasma suspends blood cells, constituting 45% of blood volume.
Major Cellular Elements of Blood
- Erythrocytes (red blood cells), leukocytes (white blood cells), and platelets; they play roles in oxygen transport, immune response, and clotting.
Sickle-Cell Disease Impact
- Genetic disorder altering hemoglobin, leading to blocked blood flow and pain; sickled cells rupture quickly.
Diving Mammals' Respiratory Adaptations
- High oxygen storage capacity, reduced heart rate during dives, and prioritized blood flow to vital organs.
Carbon Dioxide Removal and Bohr Shift
- CO2 diffuses into erythrocytes, forming bicarbonate; the Bohr shift decreases hemoglobin's oxygen affinity in active tissues.
Blood Clotting Mechanism
- Platelets aggregate and form a clot in response to vessel injury.
Role of Cholesterol in Cardiovascular Disease
- LDL delivers cholesterol to cells; HDL removes excess cholesterol. High LDL to HDL ratio increases atherosclerosis risk.
Consequences of Cardiovascular Disease
- Can result in conditions like atherosclerosis, heart attacks, and strokes.
Respiratory Surfaces in Organisms
- Gills, tracheae, and lungs serve as sites for gas exchange.
Lung Adaptations for Gas Exchange
- Varying reliance on lungs among vertebrates; amphibians may utilize skin diffusion.
Mammalian Breathing and Lung Ventilation
- Negative pressure breathing mechanism facilitates air intake; rib muscles and diaphragm contraction increase lung volume.
Definitions of Lung Volumes
- Tidal volume: air exchanged per breath; vital capacity: maximum air exchange; residual volume: air remaining after exhalation.
Control of Breathing in Humans
- Medulla oblongata regulates breathing rhythm and prevents lung overexpansion via negative feedback mechanisms.
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Description
Explore the various types of circulatory systems present in animals, including open and closed systems. This quiz covers key concepts such as the organization of the circulatory system and the unique characteristics of single and double circulation found in different species.