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Physiology Test 4
Terms in this set (76)
What are the functions of the circulatory system?
transportation of respiratory gases,delivery of nutrients and hormones, waste removal. Also plays a role in temperature regulation, clotting, and immune function
Name the two components of the circulatory system and state their major roles.
1.) Cardiovascular - heart pumps blood through cardiovascular system and the blood vessels carry blood from heart to cells and back. 2.) Lymphatic system - picks up excess fluid that has accumulated in the tissues and returns it to veins. The lymph nodes are part of the immune system.
What are the two major parts of blood?
Formed elements (cells) and plasma. The cells are suspended and carried by the plasma.
Describe blood that has been centrifuged.
When centrifuged, blood separates into heavier formed elements on the bottom and plasma on top. There are three strati (from superior to inferior) - Blood plasma, and formed elements. Formed elements are (also in sup to inf): buffy coat (made of platelets and WBCs), then RBCs.
How much blood does an adult have?
straw colored liquid of unclotted blood that consists of H2O and dissolved solutes (serem is liquid left when blood has clotted.) Plasma includes electrolytes (Ca, K, Na, etc), nutrients, hormones, and antibodies
What comprises the majority of the formed elements in blood?
What is hematocrit? And what are typical values for men and women?
% of RBCs in centrifuged blood sample. In Women: 36-46% and Men: 41-53%
What are erythrocytes? Describe them.
Erythrocytes are RBCs. They are flattened biconcave discs. The shape increases the surface area for diffusion. They lack nuclei and about 300B are produced each day.
What are leukocytes? Describe them.
Leukocytes are WBCs. They have a nucleus. They can be granular or agranular. 1.) Granular leukocytes include eosinophils, basophils and neutrophils. A.) Neutrophils are phagocytes and have a nucleus that has multiple segments, they can leave the blood stream and search for foreign bodies, they have pink granules (if this count is up, then bacterial infection). B.) Basophils release heparin which is a blood thinner, they have purple granules. C.) Eosinophils increase in allergic reactions and parasite infections. 2.) Agranular leukocytes include lymphocytes and monocytes. A.) Lymphocytes produce antibodies. B.) Monocytes are phagocytes. These are larger and eat things like fungus.
See table on 403. What is the normal WBC count? RBC count? Platelet count?
Normal WBC count: 5-10K/mm3 of blood. Leukemia WBC count: 500K/mm3 of blood (but they aren't functional). Normal RBC count: 5M/mm3 of blood. Normal Platelet count: 150K-400K /mm3 of blood.
What would a lot of reticulocytes in blood indicate?
The bone marrow is being stressed to increase the number of RBCs so they are releasing them before they are mature (reticulocyte = immature RBC). So patient probably has lost a lot of blood (internal bleeding?) or anemia, a lack of protein or iron in the diet.
What is serum?
plasma that has had the clotting factors removed.
What are thrombocytes?
Platelets. They are the smallest of the formed elements and they lack a nucleus. They are amoeboid fragments of megakaryocytes from bone marrow. They constitute most of the mass of blood clots, they release serotonin to vasoconstrict and reduce blood flow to clot area and secrete growth factors to maintain integrity of blood vessel wall. They only live 5-9 days.
This is the formation of blood cells from stem cells in bone marrow (myeloid tissue) and lymphoid tissue. The marrow produces about 500B blood cells/day. In a fetus, this occurs in the liver. The formation of RBC's is called Erythropoiesis and the formation of WBC's is Leukopoiesis.
This is the formation of RBCs. The process is stimulated by erythropoietin (EPO) secreted by the kidneys. When the kidneys detect a low amount of O2 in the blood, it secretes this hormone to stimulate this process. About 2.5M RBCs are produced every second. The lifespan of RBCs is about 120 days. Old RBCs are removed by phagocytic cells in liver, spleen and bone marrow. The iron is recycled back into hemoglobin production.
This is stimulated by cytokines. These are autocrine regulators secreted by the immune system.
What is meant by a persons blood type? A, B, AB, O. What does the +/- mean?
A only has A antigens, B only has B antigens, AB has both, and O has neither. The +/- refers to Rho(D) antigens (commonly called Rh) Rh+ has Rho(D) antigens and Rh- does not.
What type of antibodies to blood does someone make?
The opposite of what antigens on their RBCs. That is, People with Type A blood make antibodies to Type B RBCs, but not to Type A
Type B blood has antibodies to Type A RBCs but not to Type B
Type AB blood doesn't have antibodies to A or B
Type O has antibodies to both Type A and B
If different blood types are mixed, antibodies will cause mixture to agglutinate. Further Rh+/- blood will also make antibodies against. This is a problem if mom is Rh- and baby is Rh+. At birth, mom is exposed to Rh+ from baby, so mom starts to produce antibodies to it then future pregnancies the mom's blood would attach the baby's. This is erythroblastosis fetalis (preventable and mom can have vaccine to prevent this. Otherwise in utero blood transfusions for baby.)
Hemostsis is what?
Cessation of bleeding. This is promoted by reactions initiated by vessel injury. Vassoconstriction restricts blood flow to the area. A platelet plug forms. This plug and surrounding are infiltrated by a web of fibrin forming a clot.
Endothelium is what?
Very slick surface lining the inside of blood vessels. Platelets do not stick to this because of the presence of prostacyclin (a prostaglandin) and NO. (These prevent clots from forming and are vasodilators.) Damage to the endothelium allows platelets to bind to exposed collagen. Platelets stick to collogen and release ADP, serotonin, and Thromboxane A2. Serotonin and Thromboxane A2 stimulate vasoconstriction (reducing blood flow to wound) while ADP and thromboxane A2 cause other platelets to become stick and attach and undergo platelet release reaction (this continues until a platelet plug is formed).
Von Willebrand factor is what?
This increases bond by binding to both collagen and platelets. (This is the coagulating factor that starts the clotting process.) There is a disorder if someone doesn't have this factor- von Willebrand hemophilia.
What is fibrin?
This is the weblike structure that infiltrates the platelet plug. A clot now contains platelets, fibrin and RBCs that get trapped in the web.
After a clot is formed what does it do?
It will undergo plug contraction to form a more compact plug.
There are two pathways to for a fibrin polymer, what are they and give an example of each.
1.) extrinsic - tissue damage. 2.) intrinsic - vessel damage.
What are the last few steps of the conversion of fibrinogen to fibrin?
Prothrombin → thrombin → is a catalist for : fibrinogen → fibrin. Then fibrin + XIII → fibrin polymer.
How many plasma clotting factors are there?
Discuss clotting factor XIII
This is the last in the chain, it stabilizes the clot. Also deficiency of this clotting factor is one of the most common causes of hemophilia.
What is the role of plasmin
Plasmin digests fibrin, dissolving the clot.
What are some anticoagulants and how do they work?
Clotting can be prevented by Ca chelators (eg sodium citrate or EDTA) or heparin which activates antithrombin III (which blocks thrombin). Coumarin blocks clotting by inhibiting Vitamin K.
Describe the heart.
4 chambers, 2 atria, 2 ventricles, sides are separated by a muscular septum. Between atria and ventricles is a layer of dense connective tissue called fibrous skeleton. This fibrous skeleton structurally and functionally separates the atria and ventricles. Myocardial cells of atria attach to top of fibrous skeleton to form 1 unit (myocardium); cells from ventricles attach to bottom and form another unit. The fibrous skeleton also forms rings called annuli fibrosi to hold heart valves.
What is the path of blood flow through the adult heart.
Superior & Inferior Vena Cava → R Atrium → Tricuspid valve → R Ventricle → Pulmonary Trunk → Pulmonary Arteries → lungs → Pulmonary veins → L Atrium → Bicuspid valve (mitral valve) -> L Ventricle → Aorta.
Define Pulmonary circulation.
path of blood from right ventricle through lungs and back to heart
Define systemic circulation.
path of blood from left ventricle to body and back to heart
Compare the rates of flow of the systemic circulation system and the pulmonary system.
They are equal.
What is the largest chamber of the heart?
The left ventricle (it has to pump blood all through the body). Work done by the L ventricle pumping to systemic is 5-7X greater, this makes the L ventricle more muscular and 3-4X thicker. (compared to R ventricle, I'm assuming)
What are the two Atrioventricular valves and where are they located? What do they do and how to they work?
Tricuspid valve is between R Atrium and R Ventricle. Bicuspid (mitral) valve is between L Atrium and L ventricle. The valves close by blood pressure in the ventricle pushing them shut, the papillary muscles attached to the valves via the chordae tendonae keep the valves from blowing open backward thus preventing the backflow of blood.
What are the semilunar valves?
The valves at the beginning of the aorta (aortic semilunar) and pulmonary trunk (pulmonary semilunar). These close during relaxation.
Describe the cardiac cycle.
This is the repeating pattern of contraction and relaxation of the heart. Systole is contraction phase and diastole is the relaxation phase. Both atria contract followed by the ventricles (100-200ms later)
What is stroke volume?
The amount of blood ejected from the ventricles during systole phase.
What is cardiac rate?
This is the heart rate. An average is about 75 bpm.
When listening to the heart, what are you hearing?
The closing of the AV and semilunar valves. The first sound (lub) is the AV valves closing. The second (dub) is the closing of the semilunar.
What are heart murmurs?
Abnormal sounds produced by abnormal patterns of blood flow in the heart. Many are caused by defective heart valves which can be congenital in origin (septal defects foramen ovale doesn't close) or from antibodies made in response to strep infections (like rheumatic fever). Mitral stenosis is another form of a murmur. Also incompetent valves would cause a murmur.
What is mitral stenosis?
mitral valve becomes thickened and calcified, impairing blood flow from L atrium to L ventricle. The accumulation of blood in L ventricle can cause pulmonary hypertension.
What is meant by an incompetent valve?
They don't close properly. This can be from damage to papillary muscles.
The fetal bypasses in or around the heart are:
Foramen ovale - hole between atria. And Ductus Arteriosus - connects the pulmonary trunk to the aorta.
Describe the Electrical activity of the heart.
Myocardial cells are short, branched and interconnected by gap junctions (intercalated disks). The entire muscle that forms a chamber is called a myocardium or functional syncytium. AP's originating in any cell are transmitted to all others like a network. The chambers are separated from each other by nonconductive tissue. The SA node (sinoatrial node) is the pacemaker, it can spontaneously depolarize to threshold (pacemaker potential) which will cause the atria (both R and L) to contract. The AP travels to the atrioventricular node (AV node, or bundle of His) at the base of the R atrium. The His divides into R and L bundle branches which give rise to Purkinje fibers in the walls of the ventricles. These Purkinje fibers stimulate contraction of ventricles.
What are Ectopic Pacemakers?
These are other tissues in the heart that are spontaneously active. These include AV node, AV bundle (Bundle of His), and Purkinje fibers. These are all slower than the SA node. If AP's from SA node are prevented from reaching these, they will generate pacemaker potentials on their own.
Describe the P, QRS, and T waveforms
P - Atrial depolarization, Atrial contraction. QRS complex - ventricular depolarization/contraction, T - ventricular Repolarization. Notice, can't see atrial repolarization.
Also known as ateriosclerosis (hardening of arteries) Localized plaques reduce flow of an artery. This plaque is INSIDE the wall of the artery. These plaques disrupt the blood flow allowing blood clots (thrombus) to form. The plaque can get big enough to completely occlude the lumen of the vessel.
What is an embolus?
A blood clot that has broken away and is traveling through the blood.
List the four major causes of atherosclerosis.
hypertension, smoking, high blood pressure, and diabetes.
A lipid profile would include what? Briefly describe each.
Cholesterol - needed by body, made in liver and obtained from diet. LDL - low density lipoproteins - carry cholesterol to tissue. HDL - High density lipoproteins - carry cholesterol away from tissue to be excreted
Describe Ischemic Heart Disease.
Most commonly due to atherosclerosis in coronary arteries. Occurs when blood supply to tissue is deficient. Often accompanied by angina pectoris
Where on a chart would you be able to diagnose Ischemic Heart disease?
detectable by changes in S-T segment.
What is a Myocardial Infarction?
heart attack. Usually caused by occlusion in coronary artery. This causes heart muscle to die. The dead cells are replaced by scar tissue that is noncontractile. This can be diagnosed by high levels of creatine phosphokinase (CPK) or lactate dehydrogenase (LDH) and troponin T and tropinin I.
Flutter is what?
contraction rates of 200-300/min
fibrillation is what?
contraction of myocardial cells that is uncoordinated and pumping ineffective. Vfib is life threatening (quivering heart) and you can use a defibrillator. Afib is life threatening too, but not as much so (this one can cause clots).
Three basic functions of lymphatic system are:
1.) transport interstitial fluid back to blood, 2.) transports absorbed fat from small intestine to blood, 3.) helps provide immunological defenses against pathogens.
describe lymphatic capillaries
Closed-end tubes forming a vast network. They are porous and absorb proteins, microorganisms, and fat.
lymph nodes filter lymph and return it where?
to the veins via the thoracic duct or right lymphatic duct.
Lymph nodes make what?
lymphocytes and contain phagocytes that remove pathogens.
Besides the nodes, where else are lymphocytes made?
tonsils, spleen, thymus
What is Cardiac volume?
volume of blood pumped / minute by each ventricle. Cardiac Volume = Stroke Volume * Heart Rate. The total blood volume is about 5.5L
What are the controllers of the heart rate?
Sympathetic and Parasympathetic nervous systems (these are main- they modify the rate at which SA node spontaneously depolarizes.) and Epineperine and Norepinepherine (stimulate opening of pacemaker channels thus SA depolarizes faster). ACH promotes opening of K channels thus slows depolarization and decreases HR.
What coordinates the activity of the autonomic innervation of the heart?
Cardiac control center of medulla oblongata
Stroke Volume depends on three things, what are they?
1.) End diastolic volume (how much blood is in ventricles at end of diastole) 2.) Total peripheral resistance (impedance in arteries) 3.) Contractillity (strength of ventricular contraction)
In general terms, what does Frank-Sterling Law of the Heart state?
The strength of ventricular contraction varies directly with EDV. That is, the more the heart is stretched by the volume of blood, the greater the contraction.
Most blood is stored where?
venous system - they hold about 70% of blood and are called capacitance vessles. They are stretchy and hold more blood without increase pressure (higher compliance)
Venous return is dependent upon what 4 things?
1.) blood volume and venous pressure, 2.) vasoconstriction caused by sympathetic nervous system 3.) skeletal muscle pumps, 4.) pressure drop during inhalation
What is the break down of where the body stores water?
2/3 inside cells (intracellular compartment), 1/3 in extracellular compartment (of that 80% is interstitial fluid and 20% is in blood plasma)
Describe the exchange of fluid between capillaries and tissues.
This distribution is in a constant state of dynamic equilibrium. From Capillaries to tissues is driven by blood pressure. And from tissues to capillaries is driven by osmotic pressure exerted by proteins in fluid.
Edema is what and name some causes.
Edema is excessive accumulation of ECF. Some causes are: HBP, venous obstruction, leakage of plasma proteins into ECF, myxedma from hypothyroidism, low plasma protein (albumin) levels resulting from liver disease, obstruction of lymphatic drainage.
Describe the formation of urine.
urine begins forming with filtration of plasma by special capillaries called glomerulus in kidney. This filtrate passes into tubules and is modified as it travels through the nephron. The volume of urine excreted can be changed by reabsorption of various substances through the walls of the kidney tubules (it is adjusted by the bodies needs - this is governed by hormones)
ADH comes from where and does what?
It is made in the hypothalamus and stored in posterior pituitary. Osmoreceptors in brain detect high blood osmolality (caused by dehydration or salt ingestion) cause thirst and ADH to be secreted. It acts on the kidneys to cause H2O reabsorption.
What is Aldosterone?
A steroid hormone secreted by adrenal cortex. Helps maintain blood volume and pressure through retention of salt and water in kidneys. The direct effect is to raise Na, then that makes NaCl (salt), water follows salt, always. It's release is stimulated by salt deprivation, low blood volume, and low blood pressure.
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