Circulatory System Flashcards
Three components of a circulatory system
1) pump 2) system of tubes, channels, or spaces 3) fluid that circulates
Three types of pumps
1) chambered hearts 2) skeletal muscle 3) pulsating blood vessels/peristalsis
Interstitial fluid
Extracellular fluid that directly bathes tissues
Blood
Fluid that circulates within vessels of closed circulatory system
Lymph
Fluid that circulates in a secondary system in vertebrates, called the lymphatic system
Hemolymph
Fluid that circulates in an open circulatory system
Three main components of vertebrate blood
1) plasma 2) erythrocytes/red blood cells 3) other blood cells and clotting cells (leukocytes and thrombocytes/platelets_
Hematocrit
Part of blood made up of erythrocytes
Albumin
Vertebrate carrier protein in blood
Globulins
Vertebrate carrier protein in blood
Thrombin
Vertebrate blood clotting protein
Fibrinogen
Vertebrate blood clotting protein
Hemoglobin
Respiratory pigment whose major function is storing and transporting oxygen
Mechanism that sponges and flatworms use to circulate fluids in the body
Ciliated cells move water within body cavity
Mechanism that cnidarians use to circulate fluids in the body
Muscular contractions of the body wall pump water in and out of body cavity
Circulatory system of annelids
Open (ex. tube worms) and closed (ex. earthworm)
Circulatory system of molluscs
Open (most) and closed (cephalopods) but all have hearts and some blood vessels
Circulatory system of arthropods - crustaceans
Open; small sinuses function as vessels and there is some control over distribution of hemolymph flow inside body
Circulatory system of arthropods - insects
Open; multiple contractile “hearts” along dorsal vessel and a tracheal system for most gas transport
Circulatory tract of vertebrates
Heart -> arteries -> arterioles -> capillaries -> venules -> veins -> heart
Function of capillaries
Diffusion of molecules between blood and interstitial fluids
Tunica extrema
Outer layer of vessels made of collagen
Tunica media
Middle layer of vessels made of smooth muscle and elastic connective tissue
Tunica intima
Inner layer vessels before endothelium made of a smooth sheet of endothelial cells
Endothelium
Most inner layer of vessels
Veins consist of…
Tunica externa, media, and intima, then endothelium
Venules consist of…
Tunica externa, then endothelium
Capillaries consist of…
Endothelium
Arteries consist of…
Tunica externa, media, and intima, then endothelium
Arterioles consist of…
Tunica media, then endothelium
Three types of capillaries
Continuous, fenestrated, and sinusoidal
Continuous capillaries
Cells are held together by tight junctions (ex. skin, muscle, CNS blood brain barrier)
Fenestrated capillaries
Cells contain pores; specialized for exchange (ex. kidneys, endocrine organs and intestines)
Sinusoidal capillaries
A few tight junctions but are the most porous for exchange of large proteins (ex. liver and bone marrow)
Circulatory pattern of water-breathing fish
Single circuit (heart –> gills –> body –> heart)
Circulatory pattern of air breathing tetrapods (amphibians, reptiles, birds, mammals)
Two circuits: pulmonary circuit (right side of heart) and systemic circuit (left side of heart)
Amphibian and reptile heart structure
Only partially divided, with two atria and one ventricle
Cardiac cycle phases
1) systole/contraction - blood forced into circulation 2) diastole/relaxation - blood enters the heart
Arthropod heart
Heart pumps out hemolymph via arteries
Blood returns via ostia (holes) during diastole
Valves in ostia open and close to regulate flow
Mechanism of placement and control in arthropod hearts
Heart is suspended with a series of ligaments and is neurogenic/contracts in response to signals from nervous system
Mammalian myocardium: compact or spongy
Compact
Fish myocardium: compact or spongy
Spongy
Four main parts of vertebrate heart walls
1) pericardium
2) epicardium
3) myocardium
4) endocardium
Pericardium
Sac of connective tissue which surrounds heart; space between outer/parietal layer and inner/visceral layers is filled with lubricating fluid