Animals - Chapter 11 Flashcards
Importance and roles of the circulatory system
importance = organisms with 3 germ layers need a circulatory system to service the middle layers of cells
transports nutrients, waste, hormones, heat
helps defend against invading organisms by circulating immune cells
Open circulatory system
circulating fluid (hemolymph) is pumped into an interconnected system of body cavities called sinuses, where it bathes the cells directly contraction forces hemolymph out of blood vessels through sinuses, relaxation draws hemolymph back into heart through open-ended pores
Closed circulatory system
fluid (blood) is contained within a network of blood vessels
separates blood from tissues but provides a medium for diffusion of substances
Circulatory system of a fish
single circuit closed circulatory system
at the gills, blood takes in oxygen from surrounding water and deposits carbon dioxide
from gills, blood circulates to the rest of the body
atrium receives collected blood and pumps it into the ventricle, which pumps it to the gills
Two-circuit circulatory system
systemic circulation = circulates blood around the body to deliver oxygen, nutrients and substances, and to pick up carbon dioxide
pulmonary circulation = circulates blood to lungs for gas exchange
Plasma
protein rich liquid in which the blood cells and platelets are suspended
composed of water, plasma proteins and other molecules
function = solvent, clotting, lipid transport, defence, eliminating waste
Erythrocytes
red blood cells
no nucleus or mitochondria, biconcave to maximize surface area
if oxygen drops below a certain level, EPO hormone stimulates more production of red blood cells
anemia = deficiency in hemoglobin or red blood cells
Leukocytes
white blood cells
formed in bone marrow and have nuclei
functions = uses phagocytosis to engulf cells and provide protection, immune response, defense against parasitic worms
concentrated in lymph nodes
Platelets
fragmented red blood cells, originate as pinched off cytoplasmic fragments in bone marrow
initiate blood clotting
no nucleus
fragile and rupture over torn blood vessels
Blood clotting
blood vessel breaks, releasing chemicals that attract platelets
platelets stick to collagen fibres in order to form a clot, sealing holes in the blood vessel
risk = clots can become dislodged and block the flow of blood in another part of the body
Arteries and arterioles
carries blood away from the heart
usually oxygen rich, except for the pulmonary artery
3 layers of tissue = connective, smooth muscle, endothelium
walls are elastic and thick to withstand great pressure
arteries branch into smaller and smaller arterioles
Capillaries
smallest vessels in our body, vast network
thin walled to promote easy diffusion of oxygen, nutrients, and carbon dioxide
flow is regulated by sphincters
there is a decrease in the rate at which blood flows when it enters the network of capillaries because the area is much larger
this occurs in order to provide more time for diffusion
Venules and veins
capillaries merge into small venules, which merge into larger veins
veins carry blood towards the heart
one-way valves push blood towards heart
less smooth muscle, not elastic, thinner walls
skeletal muscles contract and help pump blood back to the heart
varicose veins = accumulation of blood in the veins, causing them to stretch
Blood pressure
pressure increases if vessels get smaller (vasoconstriction), blood volume increases
pressure decreases if vessels get larger (vasodilation), blood volume decreases
measured using stethoscope and sphygmomanometer
Types of pressure
systolic = ventricles begin to contract and blood is forced out of the ventricles diastolic = ventricles begin to relax and fill with blood healthy = 120 over 80
Hypertension
high blood pressure
causes = kidney disease, medications, age (loss of vessel elasticity), diet (high in sodium)
no symptoms until dire
diet, exercise and medication can reverse hypertension
Pulse
pulse = expansion of an artery in response to the increased pressure caused by the contraction of the heart
main reason for taking a pulse is to determine the heart rate
Lymphatic system
roles in both circulatory and immune systems
circulatory = ensures blood volume is maintained
immune = filters bacteria and other components from the blood
Temperature regulation
mammals control heat by changing the volume of blood in the skin
voluntary, controlled by the autonomic branch of the nervous system
The heart
right side = circulates blood to the pulmonary circuit
left side = receives this blood and pumps it out through the systemic circuit
AV valves have chordae tendinae because they are subjected to more pressure than the semilunar valves
Heart sounds
lubb = A-V valves close after atria contract
dubb = semilunar valves close after ventricles contract
heard with a stethoscope
heart murmur = inefficient blood flow and increased blood pressure
Setting the heart’s tempo
myogenic muscle = not attached to nerve, ensures heart will still beat even if the nervous system is damaged
sinoatrial node = pacemaker simulates this, cluster of nerves
atrioventricular node = impulse passed to ventricles
Purkinje fibres = pass through the septum to carry rhythm, run up along each ventricle causing contraction
Electrocardiograph
measures electrical signals
P wave = atrial contractions, simulated by SA node
QRS wave = ventricular contractions, simulated by AV node and Purkinje fibres
T wave = ventricle recovers
Artery problems (aneurysm, arteriosclerosis, atherosclerosis, coronary artery disease)
aneurysm = bulge in an artery due to a weak spot
arteriosclerosis = hardening of arteries
atherosclerosis = type of arteriosclerosis, hardening of arteries due to plaque buildup
coronary artery disease = atherosclerosis in the coronary arteries
Treating coronary artery disease
angioplasty = catheter with a balloon is inserted into femoral artery and snaked all the way to the coronary artery, balloon is expanded and stent hold the artery open
coronary bypass = section of healthy artery or vein from another part of the body is removed and put in place of blocked coronary artery
Angina and heart attacks
angina symptoms = pain//tightness in chest, pain shooting down left arm, shoulder, neck
nitroglycerine vasodilates and increases blood flow to muscles
heart attack = myocardial infarction, death of cardiac muscle
Cardiac output and stoke volume
cardiac output = the amount of blood pumped out by the heart in mL per min
stroke volume = the volume of blood pumped out of the heart with each heartbeat
cardiac output = heart rate times stroke volume
