Circulatory, Lymphatic, and Immune Systems Flashcards
What does the circulatory system do?
distributes nutrients, transports oxygen and CO2, transports metabolic waste, transports hormones, maintains homeostasis of body temp
ischemia
inadequate blood flow
arteries
carry blood away from heart at high pressure
veins
carry blood toward heart at low pressure
How does blood flow from heart
arteries to arterioles to capillaries
How does blood go back to the heart
capillaries to venues to veins to heart
role of endothelial cells
makes up inner lining of all blood vessels, vasodilation/vasoconstriction, inflammation, angiogenesis, blood clotting (thrombosis)
atria
where blood is collected from veins before being pumped into ventricles
ventricles
push blood into arteries
right atrium vs left atrium
right receives deoxygenated blood to pump into right ventricle and left receives oxygenated blood to pump into left ventricle
AV valve
prevents back flow between each ventricle and its atrium
bicuspid valve
AV valve between left atrium and left ventricle
diastole
ventricles are relaxed and blood is able to flow into them from the atria
systole
ventricles contract, causing a buildup of pressure that shuts the AV valves
At the end of systole, blood starts to flow backward from the pulmonary artery to the right ventricle and from the aorta into the left ventricle
Semilunar values slam shut when pressure in ventricles is lower
cardiac output formula
cardiac output = stroke volume * heart rate
venous return and how it is increased
return of blood to heart by vena cava
can be increased by increasing total volume of blood in circulatory system and contraction of large veins that propel blood toward the heart
How do cardiac muscle cells communicate
via gap junctions
slow calcium channel
involved In cardiac muscle action potential and stays open longer than fast sodium channels, leading to a more depolarization
SA node
pacemaker of the heart, initiates each action potential
cardiac conduction system
conducts transmission of action potential in heart from atrial syncytium to ventricles
T tubules
Where action potentials travel down along in cardiac muscle and calcium enters and is released from sarcoplasmic reticulum.
SA node phases
Phase 4 - automatic slow depolarization caused by sodium leak channels
Phase 0 - opening of voltage gated calcium channels driving membrane potential toward positive Ca2+ equilibrium
Phase 3 - repolarization caused by closure of the Ca2+ Channels and opening of the K+ channels
cardiac muscle cell membrane potential phases
Phase 0 - depolarization due to increase in Na+ conductance
Phase 1 - initial repolarization due to Na+ channels inactivating and K+ channels opening
Phase 3 - repolarization occurs when Ca2+ channels close and K+ channels continue to allow K+ to leave
direction of action potential in the heart
Action potential starts in SA Node and spreads throughout atria, causing them to contract and fill ventricles with blood
Impulse also travels to AV node, then to the ventricles via the conduction pathway, also known as the AV bundle (bundle of His)
Impulse then moves to Purkinje fibers, which allows the impulse to spread rapidly and evenly over both ventricles
vagal tone
constant level of inhibition provided by the vagus nerve via release of ACh
baroreceptors
monitor pressure and notify CNS about needed changes
What is the driving force for blood flow
difference in pressure from arteries to veins
Ohm’s law
Delta P = Q * R
P = pressure gradient from arterial system to venous system Q = blood flow R = resistance
What determines resistance and how is the sympathetic system involved?
degree of constriction of arteriolar smooth muscle
Sympathetic system can increase the overall peripheral resistance
What is the lowest arterial pressure occurring at any time during the cardiac cycle?
Diastolic pressure
local auto regulation
tissues in need of extra blood flow are able to requisition it themselves
What is blood made up of?
plasma, leukocytes, hematocrit
Rh factor
main antigen used in blood typing, helps determine if blood type will be positive or negative, expressed in classically dominant pattern
white blood cell role
fights infection and dispose of debris
macrophages and neutrophils
white blood cells that move by amoeboid motility
platelet function
aggregate at site of damage to a blood vessel wall and stops bleeding
hemoglobin
part of RBCs, composed of four polypeptide subunits
tense confirmation of hemoglobin
when no oxygen is bound, hemoglobin has low affinity for oxygen
relaxed conformation of hemoglobin
higher affinity for oxygen, causes hemoglobin to communicate with other subunits to increase their affinity for oxygen, causing it to bind oxygen cooperatively.
How is Co2 transported in the blood
73 % - conversion of CO2 to carbonic acid,
around 20 % - some is stuck onto hemoglobin sites (not oxygen binding sites),
around 7 %- some can dissolve in the blood and be carried from the tissues to the lungs
hepatic portal vein
carries amino acids and glucose to the liver
How are lipids passed through the bloodstream
They are packaged into chylomicrons, which enter tiny lymphatic vessels in the intestinal wall called lacteals, which empty into larger lymphatics.
Why does water have a greater tendency to flow out of capillaries?
- hydrostatic pressure created by heart tends to squeeze water out of capillaries
- high osmolarity of the tissues tends to draw water out of the bloodstream
lymphatic system function
acts like a suction pump to retrieve water, proteins, and white blood cells from the tissues
lymph
fluid in lymphatic vessels, filtered by lymph nodes
innate immunity
provides general nonspecific protection against invaders,
includes skin, tears, saliva, blood, stomach acidity, macrophages and neutrophils, and complement system
humoral immunity
protection by proteins in plasma called antibodies or immunoglobulins
antibody variable region
responsible for the specificity of the antibodies in recognizing foreign particles, where the antigen binds
B cells
a type of lymphocyte that produces antibodies, can be plasma cells (actively produced) or memory cells (released when antigen appears)
role of T helpers and T killers
T helpers activate B cells, T killer cells, and other cells of the immune system
T killer cells destroy abnormal host cells
MHC I and MHC II role in cell immunity
T killer cells detect viral proteins displayed on MHC I, causing it to become active
MHC II functions as antigen presenting cells and chop up cells. They display the fragments which T helpers recognize. The T helpers then activate B cells specific for the antigen.
spleen function
filters the blood and is a site of immune cell interactions
How is autoimmunity prevented
Only the B cells whose surface receptors bind to no normal proteins during maturation are released into circulation. A similar process occurs in T cells.
Without this process, an autoimmune reaction can occur.
what are the blood proteins, mostly made by the liver?
albumin- essential for maintenance of oncotic pressure, a rise in osmotically active albumin in the serum increases flow of interstitial fluid inot bloodstream, increasing blood pressure
immunoglobulins (antibodies),
fibrinogen (essential for blood clotting, aka hemostasis lipoproteins - transport lipids in the blood stream
what is the function of bone marrow stem cells?
where formed elements of blood develop from
erythrocytes vs leukocytes
red vs white blood cells, white blood cells account for less volume in red blood cells
