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Where does systemic circulation begin and end? Describe pathway.
Where does pulmonary circulation begin and end? Describe pathway.
Begins in left ventricle and ends in right atrium.
L ventricle --> Aorta --> arteries --> arterioles --> capillaries --> venules --> veins --> superior/inferior vena cava --> right atrium.
Pulmonary circulation begins in right atrium and ends in left atrium.
Right atrium--> Right ventricle --> pulmonary arteries --> pulmonary arterioles --> pulmonary capillaries (gas exchange) --> pulmonary venules --> pulmonary veins --> left atrium
1. What is the difference between systole and diastole?
2. Would you consider the entire system to be a closed circulatory system? Why?
3. Which part of nervous system controls contractions of heart?
- 1. Systole: contraction of ventricles; diastole: relaxation of entire heart and then contraction of atria.
- 2. Yes, bc there are no openings for blood to leave vessels.
- 3. Autonomic nervous system
1. What propels blood?
2. What is the sinoatrial (SA) node? Where is it located?
3. What is the role of the vagus nerve? What system controls it?
4. What does the atroventricular (AV) node do?
1. Hydrostatic pressure created by heart contractions.
2. Specialized autorhythmic (contracts on its own) cardiac muscle cells in right atrium in charge of pacing heart contractions via electrical synapses made from gap junctions. Autorhythmic contractions spread contractions to nearby heart muscles.
3. Vagus nerve (controlled by parasympathetic NS) innervates SA node, slowing contractions.
4. Stimulated to contract by SA node, but is slower to contract, allowing atria to finish their contraction and to squeeze their contents into ventricles before ventricles contract. aka Delays contraction of ventricles of heart!!!
1. What is the bundle of His? Where does signal come from before hitting bundle of His?
2. What are Purkinje fibers? Where are they found? What do these fibers allow for?
- 1. Conductive fibers stimulated by AV node.
- 2. Purkinje fibers (ventricles) are conductive fibers allowing for a stronger, more unified contraction.
1. How does stroke volume vary for each ventricle?
2. What is responsible for the spread of cardiac action potential from one cardiac muscle cell to the next?
3. If your blood volume is falling quickly, what is the most likely reason?
1. It doesn't - both ventricles must pump the same amount otherwise there will be a backlog or one part will run dry.
2. Ion movement via gap junctions
3. Arterial bleeding due to higher pressure
1. What is one characteristic common to arteries veins and capillaries?
2. Which blood vessels have valves to prevent backflow of blood?
3. Which types of vessels can dilate or constrict to regulate blood flow?
4. Which vessels allow for exchange of nutrients with surrounding tissues?
- 1. Presence of layer of endothelial cells.
- 2. Only veins
- 3. For MCAT purposes, only arterioles.
- 4. ONLY capillaries.
1. Are arteries elastic?
2. What is a powerful vasoconstrictor?
3. How thick are capillaries? What is main purpose of capillaries (2)?
- 1. Yes.
- 2. Epinephrine
- 3. One cell thick. Nutrient and gas exchange.
1. Describe the balance between hydrostatic pressure and osmotic pressure in net fluid flow in capillaries.
2. How does osmotic pressure change within a capillary?
3. How much fluid is lost to interstitium?
1. As blood flows into capillary, hydrostatic pressure > osmotic pressure, so net fluid flow is out of capillary into interstitium.
At venule end, hydrostatic pressure drops < osmotic pressure, so net fluid flow is into capillary and out of interstitium.
2. It doesn't - it stays relatively constant.
3. ~10% of fluid.
1. What are two differences between veins/venules and arteries/arterioles/capillaries?
2. In which vessels does blood move fastest and slowest? Which vessels have highest resistance to flow? Greatest cross sectional area?
3. What is the major contribute to pressure in blood vessels? What else contributes to helping blood move through veins?
4. How do veins compensate for lower pressure?
1. Veins have larger lumen (4x that of arteries) and contain more blood.
2. Blood in capillaries move slowest, bc total cross sectional area of capillaries is greater than arteries. Blood moves at a constant speed everywhere else.
3. Pumping force of heart. Skeletal muscle
4. Valve system to prevent backflow.
How does blood pressure vary in different vessels?
Where is it lowest? Where does it rise again? Where is it highest?
- Lowest: veins
- Rises again in pulmonary arteries
- Highest: Aorta/larger arteries/small arteries
1. In which artery can you find deoxygenated blood?
1. Pulmonary artery.
1. What is the pathway of air from nose to alveoli? 7
2. Where does gas exchange take place?
3. Main function of respiratory system?
1. Nose --> pharynx (throat) --> larynx (voice box) --> trachea (windpipe in front of esophagus) --> bronchi --> bronchioles --> alveoli
2. In capillaries of alveoli
3. To deliver oxygen to blood and expel CO2
1. What is it called when oxygen binds with Hb?
2. How many atoms of iron are in Hb?
3. How do PCO2, acidity, and temperature increases affect Hb's affinity for O2? How does this affect the O2 dissociation curve?
4. CO has 200x more affinity for Hb than does O2. What direction would it shift the curve?
2. 4 - one for each heme subunit
3. Increased PCO2, acidity, and temperature decrease Hb's affinity for O2, shifting sigmoidal O2 dissociation curve to the right.
4. To the left.
1. In what 3 forms is CO2 carried in the blood?
2. What is the rxn for carbon dioxide --> bicarbonate?
3. What happens if you have too much acid in blood?
4. What acts as a blood buffer? How?
5. What monitors O2 and pH?
1. In physical solution, as bicarbonate ion, and in carbamino compounds (combined with Hb and other proteins)
2. CO2 + H2O --> HCO3- + H+ (most common form of CO2 in body)
3. Breathing rate will increase to expel CO2 to raise pH of blood.
4. Reduced (O2-less) Hb, bc it can accept protons .
5. Peripheral chemoreceptors in carotid arteries.
1. Function of lymphatic system?
2. What tissues are not drained by lymphatic channels?
3. Is the lymphatic system a closed system? Why or why not?
4. Can lymph system deal with larger molecules, like proteins?
- 1. Collects excess interstitial fluid, monitors blood for infection, and returns it to blood.
- 2. CNS
- 3. No, it's open, bc fluid enters at one end and leaves at the other.
- 4. Yes
1. How is fluid propelled through lymphatic valves? (2)
2. Is lymph flow greater in an active individual or a sleepign one?
3. Where are lymphocytes located?
- 1. Smooth muscle in walls of larger lymph vessels contract when stretched and next, lymph vessels may be squeezed by adjacent skeletal muscles, body movements, etc.
- 2. Active
- 3. In lymph nodes
1. What type of tissue is blood?
2. What is blood's function? (6)
3. What are 3 important proteins in blood?
- 1. Connective - contains cell and matrix
- 2. Regulates EC environment of body by transporting nutrients, waste products, hormones and heat. Also protects body from injury and foreign invaders.
- 3. Albumin, immunoglobulins, clotting factors
1. What is the function of albumin? (2)
2. What is serum?
3. What is a random important function of plasma proteins?
4. What type of immunoglobulin is made in lymph tissue?
- 1. Transport of FAs and steroids, as well as regulating osmotic pressure in blood.
- 2. Serum is plasma without the clotting protein fibrogenin.
- 3. To act as a source of AAs for tissue protein replacement.
- 4. Gamma globulin
1. What is the main function of RBCs aka erythryocytes? What are 4 weird things about them? Where are they destroyed?
2. What is another name for leukocytes? Do they have organelles? What is their main function?
3. Where do blood cells come from? (cell and part of body)
4. Why do granulocytes live a short time while agranulocytes live a long time?
1. To transport O2 and CO2. No organelles, no nucleus, no mitosis, no reproduction. Liver and spleen.
2. White blood cells. Yes. To protect body from foreign invaders
3. Stem cells in bone marrow
4. Bc granulocytes function nonspecifically against all infective agents while agranulocytes work against specific agents of infection - so they need to hang around in case that specific agent of infection returns.
Granulocytes multiply quickly against any infection and die when infection is gone.
Where do lymphatic vessels carry absorbed fluid from interstitial places?
An individual exposed to a pathogen for the first time will exhibit an innate immune response involving?
Lymphatic ducts which return it to circulation.
Granulocytes - part of the innate immune system. B lymphocytes and T lymphocytes are both part of the acquired immune system.
What are the two types of ways that the body can protect itself from infectious microbes and toxins?
Which type is humoral immunity?
Do antibodies phagocytize stuff? If not, what do they do?
innate and acquired immunity
Specific & acquired.
No. They bind to antigens with their variable portions to tag them for macrophages to eat them. They are immunoglobulins produced by B-cells.
1. What does innate immunity include? (4) What is it?
2. What are the two types of acquired immunity? When does it develop? What is it?
1. Skin, stomach acid and digestive enzymes, phagocytotic cells, and chemicals in blood.
It is a generalized protection against most intruding organisms and toxins.
2. Humoral (B-cell) immunity and cell-mediated (T-cell immunity).
It develops after body is first attacked (~20 days for primary response and 5 days for secondary).
Protection against specific toxins and organisms.
1. What does injury to tissue result in? What does that include? (5)
1. Inflammation - dilation of blood vessels, increased permeability of capillaries, swelling of tissue cells, migration of granulocytes and macrophages to inflamed areas, and walling off effected tissue and local lymph vessels from the rest of the body to impede spread of infection.
Describe the process following a bacterial infection? 6 steps
- 1. Inflammation
- 2. Macrophages, then neutrophils engulf bacteria
- 3. Interstitial fluid is washed into lymphatic system where lymphocytes wait in lymph nodes.
- 4. Macrophages process and present the bacterial antigens to B lymphocytes.
- 5. Helper T cells aid in B lymphocyte differentiation into memory cells and plasma cells.
- 6. Memory cells are preparation in the even that this specific antigen comes back (secondary response), while plasma cells produce free antibodies which are released into blood to attack bacteria.
1. What cell is most important in humoral immunity? Where do these cells come from?
2. What happens when humoral immunity is activated?
1. B lymphocytes, from the liver and bone marrow.
2. Each B lymphocyte makes a single type of antibody (immunoglobulin) which it displays on its membrane.
Next, antibody recognizes antigen and binds to antigen; macrophages consume antigen and display antigenic determinants on their membrane.
If B lymphocyte antibody contacts a matching antigen presented by a macrophage, it will differentiate (w/ help of Helper T cells) into plasma cells and memory cells.
Plasma cells synthesize free antibodies and release them into blood.
If antibodies bind to antigen again, they will mark antigen for phagocytosis by macrophages and natural killer cells, may cause antigenic substances to agglutinate, or may block its chemically active portion..
What is the difference between primary and secondary response?
What is the humoral immunity effective against? 5
Primary is the first time the immune system is exposed to the antigen (requires 20 days to reach full potential)
Secondary response is the result of proliferation of memory B cells that remain int he body. In the case of re-infection, memory B cells can be called upon to synthesize antibodies, resulting in a faster and more potent reaction.
Bacterial infections, viruses, toxins, fungi, parasites
1. Where do T-lymphocytes mature?
2. How do T lymphocytes interactions with antibodies compare to B lymphocytes?
3. What important step happens in thymus while T lymphocyte is maturing?
- 1. In thymus
- 2. They both display antibody/antibody like proteins on their surface that recognize antigens, but they do NOT make free antibodies.
- 3. T lymphocyte is tested against self-antigens (antigens expressed by normal cells in body). If the T-lymphocyte binds to that self antigen, it will be destroyed.
1. What can T cells be differentiated into? What do each of these do?
1. Helper T cells = activate B lymphocytes, killer and suppressor T cells
2. Memory T cells - similar to Memory B cells
3. Suppressor T cells play negative feedback role in immune system. They shut down T cell mediated activity at end of immune reaction and kill escaped autoimmune T cells.
4. Killer T cells - bridge innate and adaptive immune system. They bind to antigen carrying cell and release a protein which punctures the antigen-carrying cell. They can attack many cells bc they do not phagocytize their victims.
What are natural killer cells? What immune response are they part of? What do they do?
They are part of the cytotoxic innate immune system.
They respond rapidly to viruses, infections, and tumors triggering lysis and apoptosis without needing antibodies or antigens.
What can you tell me about specificity of lymphocytes, antibodies and antigen?
A single B lymphocyte only produces one antibody type which is specific for a single antigen.
What antigens does type O blood have? What types of antibodies does it make?
What is the deal with Rh factor?
What describes the genes that produce A and B?
O: no A or B antigens, makes A and B antibodies
Basically, if a blood cell has a certain type of antigen, the immune system will NOT make that antibody!
- If an Rh - mom has a Rh+ fetus, the first fetus is fine, but any Rh+ fetus after that is susceptible to attack by mom's antibodies.