Circulatory Systems Flashcards
What do cells need to allows exchange of gases and nutrients?
sufficient surface area
What does diffusion put limits on?
Stay small
Thin Tissue Layers
What do circulatory systems do?
move fluid through body to quickly carry materials
What do circulatory systems employ?
bulk flow of circulatory fluid to carry materials from one place to another in the body quickly and efficiently
What are the three basic components of all circulatory systems?
Circulatory Fluid: Hemolymph or Blood carrying dissolved gases and nutrients
Tube (Vessels): short or long
Muscular Pump: the heart, provides force to move fluid
What are open circulatory systems?
organs in body that are directly bathed in hemolymph pumped by the heart through short vessels that are empty into the Coelom. Direct contact allows exchanges. Heart contraction creates negative prcssure that draws the fluid back through pores to complete circulation
What are closed circulatory systems?
blood is transferred through blood vessels
blood is confined to vessels that separate it from interstitial fluid in the coelom
Heart pumps fluid through larger vessels that branch into smaller vessels
Smaller vessels infiltrate the tissues and organs to bring gases/nutrients to individual cells
What are the three types of blood vessels?
arteries: carry blood from heart by branching into Arterioles and Capillaries
capillaries: infiltrate organs, thus allowing diffusion into cells
veins: capillaries merge into venues/veins to carry blood towards the heart
Describe arteries.
They have an endothelium, layer of cells that reduces resistance to flow
surrounded by smooth muscle followed by connective tissue
has thicker walls than veins due to high pressure of blood pumped from the heart
Describe capillaries.
branch from arterioles, which branch from arteries, and from capillary beds
highly branched vessels can bring blood to the organs and exchange molecules into cells via diffusion
capillaries are think and are only surrounded by an extracellular layer of basal lamina
Describe veins.
capillaries merge into venues, that then merge into veins that bring blood back to the heart
also have endothelium that is surrounded by smooth muscle then connective tissue
muscle contraction and valves are needed to move blood since they’re under a lower pressure
Where is velocity of blood the slowest?
in capillary beds due to the large total cross-sectional area where zones of high resistance exist
Slow flow is beneficial so diffusion can efficiently occur
What is the heart made of?
cardiac muscle
acts as the pump that moves the blood through the vessels
What are the chamber types of the heart?
atria: chamber where blood enters heart
ventricle: chamber that pumps blood out of the heart when contracted
What are the goals of the cardiovascular system?
gas exchange: deliver oxygen, remove carbon dioxide
energy balance: deliver nutrients and remove waste
osmoregulation: carry waters, ions, and hormones
What is single circulation?
blood passes respiratory organs and body tissues before returning to the heart
2 chamber hearts
What is double circulation?
blood goes to respiratory organs, back to heart, and is pumped agin to body tissues
3 or 4 chamber hearts
What does double circulation allow?
high activity and endothermicity since higher pressure means faster and constant deliver of energy, gases, and nutrients
What is a pulmonary circuit?
the vessel circuit that goes from heart to lungs to heart
What is a systemic circuit?
goes from heart to organs/muscles to heart
What is the purpose of valves?
prevents blood back flow
ensures one direction flow
What are atrioventricular valves?
regulate blood flow between atriums and ventricles
What are semilunar valves?
control blood flow to the aorta and pulmonary artery
What is the cardiac cycle?
the cycle of rhythmic heart contraction and relaxation
What does systole mean?
pumping phases during contraction
What diastole mean?
filling phases during relaxation
What is the first step during contraction?
atria diastole
ventricle diastole
relaxation fills chambers
What is the second step during contraction?
atria systole
ventricle diastole
forces all blood into ventricles
What is the third step during contraction?
atria diastole
ventricle systole
blood pumped out to arteries
What is the sinoatrial node?
muscles cells that can be self-excited by slowly depolarized over time, and resetting
pacemaker
What does the SA node do?
sends action potentials via gap junctions to neighboring cells
action potentials pause at the AV node to allow atria emptying before rest of heart contracts
What is blood pressure?
the hydrostatic pressure blood exerts against the wall of vessels
What is systolic pressure?
the highest pressure in the arteries, during ventricular systole
What is diastolic pressure?
pressure in the arteries during diastole
What is plasma?
a liquid matrix that makes 2/3 of blood volume
influences blood pH, pressure, aids transport of nutrients, aids clotting, a transport medium
What are platelets?
fragments of cells that are involved in clotting wounds
What are white blood cells?
make up immune system
many types
What are red blood cells?
transport oxygen on hemoglobin
