CH 42 Flashcards
`gills
-example of specialized gas exchange system in aniamls
-most cells in multicellular animals cannot directly exchange w/ environment
-out of foldings of the body that create a large surface area for gas exchange
-use countercurrent exchange
diffusion time
porptotional to the square of distance
-only efficient over small distances
gastrovascular cavities
-have this instead of circulatory system
-Cnidarians
-fnctions as both digestion and distribution of substances throughout body
-wall that encloses is only 2 cells think
–flatworms
circulatory system
minimizes diffusion distance in animals w/ many cell layers
-has circulatory fluid, set of interconnnecting vessels, and muscular pump (heart)
-can be open or closed and vary in number of circuits
-in all vertebrates and some invertebrates
open circulatory system
-insectcs, arthropods, and most molluscs
-blood bathes organs directly
-there is no distinction between blood and interstitial fluid
-body is full of hemolymph
-fluid that is pumped comes into direct contact with all cells
closed circulatory system
-blood is confined to vessels and distinct from interstitial fluid
-more efficient at transporting circulatory fluids to tissues and cells
-annelids, cephalopods, and vertebrates
-contain blood and specialized connective tissue
cardiovascular system
-closed circulatory system in humans and other vertebrates
-arteries, veins, and capillaries ( bloods flows in one direction)
arteries
branch into arterioles
-carry blood away from heart to capillaries
-distinguished by flow not O2 content
network of capillaries
-called capillary beds
-sites of chemical exchange between blood and interstitial fluid
-blood flow through only 5-10% at a time
-major organ and usually filled to capacity
-difference between BP and osmotic pressure drives fluids out of capillaries at arteriole into venule end
venules
converge into veins (distinguished by flow not O2 content
-return blood from capillaries into the heart
atrium
blood enters here and is pumped out of ventricle
single circulation
-bony fishes, sharks, and rays
–2 chambered heart
-bloood leaving the heart passes through capillary beds (of gills and body) before returning to heart
-oxygen poor blood goes through heart
double circulation
Oxygen poor and oxygen rich blood are pumped separately from the right and left sides of the heart
-amphibians, reptiles (w/ pulmonary and system circuits), mammals
oxygen poor blood
(reptiles and mammals)
Flows through the pulmonary circuit to pick up oxygen through the lungs
oxygen poor blood (amphibians )
Flows through a pulmocutaneous circuit to pick up oxygen through lungs and skin
amphibians and frogs
-Have three chambered heart (two atria and one ventricle)
-The ventricle pumps blood into a forked artery that splits the output of the ventricles into the promo continuous circuit in the system circuit
reptiles except birds
turtles, snakes, and lizards
-have a three chambered heart, two atria and one ventricle
-alligators and Caymans and other crocodiles have septum that divides ventricle
mammals and birds
Have four chambered heart with two atria in two ventricles
-left side pumps and receives oxygen rich blood and right side receives and pumps only oxygen poor blood
-endotherms (require more O2 than ectoderms)
mammalian circulation
-blood flow begins with the right ventricle pump blood into the lungs
-lungs load O2 and unload CO2 from blood
-oxygen rich blood from the lungs enters a heart at the left and trim and his pump through the aorta to body tissues by left ventricle
aorta
Provides blood to the heart through coronary arteries
blood flow order
-vena cava
-right atrium
-tricupid valve
-right ventricle
-pulmanory semilunar valve
-pulmonary artery
-pulmonary veins
-left atrium
-biscuspid valve
-left ventricle
-aorta semilunar valve
aorta
superior vena cava
-blood returns to heart from head, neck, and forelimbs
-flow into right atrium
inferior vena cava
-blood from trunk and hind limbs
-flow into right atrium
cardiac cycle
-heart contracts and relaxes in rhythmic cycle
systole
contraction or pumping
-animals w/ longer necks need higher systolic pressure
diastole
relaxation or filling
heart rate
pulse
-number of beats/min
stroke volume
amount of blood pumped in single contraction
cardiac output
volume of blood pumped into systemic circulation/min
-depends on both heart and stroke volume
4 valves prevent backfloow of blood in heart
-atrioventicular valves: seperate atrium and ventricle
-semilunar valves: control blood flow to aorta and pulmonary artery
“lub dup” sound
caused by recoil of blood against AV valves (lub) then semilunar valve (dub) valves
heart murmur
caused by back flow of blood through defective valve
sinoatrial (SA) node
-pace maker
-sets rate and timing at which cardiac muscle cells contract
-impulses travek to atrioventricular node
electrocardiogram (ECG or EKG)
-records impulses thatvtravel during cardiac cycle
atrioventricular node
impulses are delayed
-then travel to Purkinje fibers that make ventricles contract
pacemaker
-regulated by sympathetic (speeds it up) and parasympathetic divisions (slows it down)
-regulated by hormones and temp.
patterns of blood pressure and flow
Reflect the structure and arrangement of blood vessels
central lumen
-vessels cavity