Ch 42 Flashcards
Nutrient exchange can occur directly in
Unicellular organisms
Gastrovascular Cavities
Ensure diffusional distances are short
Common features of open and closed systems
Circulatory fluid (blood or lymph)
Vessels (movement)
Pump (provide pressure)
Open Circulatory systems are found in
Insects; arthropods; mollusks
Ostia
One way pores in open circulation
Open circulatory system
Pumps hemolymph through sinuses that surround the organs
Relax hemolymph back through Ostia
Closed Circulatory systems are found in
Vertebrates, Earthworms, Squid, Octopus
Closed circulatory system
Blood is confined in vessels and distinct from interstitial fluid
Main components of Closed circulatory system
Arteries (away from heart)
Veins (toward heart)
Capillaries (has exchange)
Which of the following is not a component of the basic circulatory system
Oxygen carrying pigment
Pulmonary
Heart to and from lungs
Lungs add oxygen
Systemic
Heart to and from other organs
Sends oxygen to the rest of the body
Diastole
“Filling” period when specific chambers relax after a contraction
Pressure is relieved in arteries
Systole
“Pumping” period of active contraction
Blood pressure is greatest in arteries
Cardiac Output =
Heart rate X stroke volume
Average HR
~70bpm
~70mL
What drives the cardiac cycle
Pacemaker Cells
Sinoatrial node
Atrioventricular node
Pacemaker cells
Produce electrical signals the cause precisely timed contractions of atria and vesicles
SA node
Has fastest rhythm- sets heart rhythm
AV node
Has slower rhythm
Blood pressure is determined by
Cardiac output and total peripheral resistance
Total peripheral resistance
Largely determined by diameter of arterioles
Measurement of blood pressure
Cuts off pressure and measures recovery time
Systolic/Diastolic
If pressure is low in venous system, how does blood get to the heart
Skeletal muscle pump
Respiratory pump
