Chapter 50: Circulatory System Flashcards
What makes up the circulatory system?
Heart, blood vessels, and the blood
Why do animals need a circulatory system?
Needed to obtain nutrients and get rid of wastes
What animals do not require a circulatory system?
-Single-celled organisms exchange directly with the environment
•Structures and body shapes allow for this
-Gastrovascular systems bring the external environment inside the animals (sponges)
What are the two types of circulatory systems?
Open and closed
What makes up the open circulatory system?
-Arteries, valve, pump, and ostium
-The blood (hemolymph) flows to the tissues and to the ostium (returns blood to the heart to be pumped again)
•No capillaries
What makes up the closed circulatory system?
-Arteries, valve, and pump
-Blood never leaves the circulatory system. It is exchanged within the system via the capillaries to the tissues
-Extracellular fluid
•Fluid inside and outside the circulatory system
o In the circulatory system: Blood plasma
o Around the cells: interstitial fluid
•Blood is kept separate from the interstitial fluid
Advantages to a closed circulatory system
-Faster transport through vessels
-Blood can be directed to specific tissue by varying resistance
o When you’re cold, your circulatory system constricts the blood vessels (keep the blood away from the skin) in order to keep your warmer
-Specialized carrier can travel in the vessels and transport hormones or nutrients to specific sites
o Metabolic cost to maintain the circulatory system
What are the two circuits to the closed circulatory system? What do they do?
-Pulmonary circuit: blood travels from the heart to the rest of the body and back to the heart
o Right ventricle
o Get rid of CO2
-Systemic circuit: blood travels from the heart to the rest of the body and back to the heart
o Left ventricle
o Deliver blood through capillaries to provide resources
What does the closed circulatory system contain?
Arteries, Capillaries, and Venules
What do arteries do?
Cary blood away from the heart and branch into arterioles (smaller arteries) that feed the capillary beds
What are capillaries? What do they do?
The site of exchange between blood and tissue fluid
-Thin and small
-Give oxygen and pick up wastes and nutrients
-Red blood cells have to go single file through the capillary
Oxygen and nutrients go out, and carbon dioxide and wastes go in
What do the Venules do?
Drain the capillary beds and form veins, which deliver blood back to the heart
What is a bruise?
Damage to the capillary beds
What do two-chambered hearts contain?
- Atrium: receives blood from the body via the veins
- Ventricle: receives pumped blood from the atrium and sends it to the gills
- Blood from the gills collects in the aorta and is distributed throughout the body
Drop of Blood through the heart (Steps)
Blood enters through major veins into the right atria
-Main entry ways:
• Superior Vena Cava, Inferior Vena Cava, Coronary Sinus
-The blood (deoxygenated) will open up the tricuspid value and go from the right atrium into the right ventricle via the AV valve
-The artia will contract (adding more blood to the ventricle) due to SA node
•Causes the AV valve to seal shut
-Blood goes into the pulmonary trump to the pulmonary artery (deoxygenated)
-The force of the ventricular contraction pushes the blood that way
-Blood goes to the lungs, where it’ll be oxygenated
-Oxygenated blood returns to the left atrium of the heart though the pulmonary veins
-The ventricle fills as blood enters through an AV valve
-The left atrium contracts and pushes the blood to the left ventricle
-Left ventricle contracts and pushes the blood through the left aorta
What is the superior vena cava?
returns blood from the tissues in the upper body (anything above the diaphragm)
What is the inferior vana cava?
returns blood from the lower body (anything below the diaphragm)
What is the coronary sinus?
on the posterior part of the heart. Blood returning to the heart from the heart
Benefits to four-chambered hearts with two atria and two ventricles
-With separate pulmonary and systemic circuits
Systemic circuit always receives blood with higher O2 content
Gas exchange is maximized (due to chambers)
Circuits can operate at different pressures
What are heart murmurs?
Heart murmur detected in leak of the tricuspid valve and mitral valve
What are Atrioventricular valves ?
lie between the atria and ventricles and prevent backflow when ventricles contract
what are pulmonary valves?
ie between the ventricles and the major arteries and prevent backflow when ventricles relax
Describe the cardiac cycle
-Cardiac cycle: two artia contract and then the two ventricles
o Systole: when ventricles contract
o Diastole: When ventricles relax
How are cells in electrical contact with each other?
Gap junctions
