PET 3323C Unit 3 Exam Flashcards

What is the role of blood in the body?

To provide oxygen, remove CO2, nourish every tissue in the body, prevent infection, and maintain: body temperature, normal pH (7.35-7.45), fluid volume

What is the makeup of the blood

Plasma is 55%, erthrocytes are 45%, and the buffy coat is less than 1% (it contains leukocytes and platelets)

What are the hematocrit values in different populations?

Newborns are 55%, adult men 45%, and adult women 40%

What is the composition of plasma?

Water (90%). proteins (albumin, fibrinogen, globulins, electrolytes, nutrients, gases, hormones and waste products)

What remains after blood clotting?

Serum

What is the composition of serum?

The same as plasma but without fibrinogen

What are the key features of erthrocytes (RBC)?

No nucleus or organelles, depressed center (allows for more surface area for gas exchange)

What are the key features of leukocytes?

These are the white blood cells, and they are the only true cells.

What is the key feature of platelets?

They are cell fragments

Describe deoxyhemoglobin

Hemoglobin with the O2 detached (low O2 concentrations)

Describe oxyhemoglobin

Hemoglobin with the O2 attached (high O2 concentrations)

What makes up the hemoglobin structure?

It is made up of 4 globin chains (2 alpha and 2 beta). Each globin chain is in charge of a heme group, binding O2. The subunits cooperate, so once one globin binds O2 the others bind it to a greater degree

What substance do the kidneys secrete to increase RBC production?

Erythropoietin

What causes the kidneys to release erythropoietin?

Hypoxia- a result of low O2 delivery, which can occur due to decreased RBC count, decreased amount of hemoglobin, and decreased O2 availability

What triggers cause increases in hematopoiesis?

Hypoxia, low RBC count, decreased amount of hemoglobin,

How does the pathway that causes an increase is hematopoiesis work?

Trigger → kidneys release erythropoietin → erythropoietin stimulates red blood marrow → increased erythropoietin increases RBC count → blood O2 rises

What causes low RBC counts?

Describe sickle cell anemia

A mutation in the hemoglobin gene causes production of abnormal hemoglobin. There are an inadequate number of healthy RBCs to carry oxygen through the body, as the abnormal (sickle) shape stops RBCs from traveling to small capillaries and causes poor O2 carrying capacity

Describe thalassemia

An inherited blood disorder, the body makes an abnormal form/inadequate amount of hemoglobin. Here, the erythrocytes are thin, delicate, and hemoglobin deficient

Describe hemolytic anemia

It is the breakdown of RBCs due to infection or improper immune cell function, characterized by low RBC

Describe aplastic anemia

A form of bone marrow failure due to damage to stem cells that produce new blood cells, characterized by low RBCs

Describe hemorrhagic anemia

Anemia due to blood loss from a hemorrhage, characterized by low RBC

Describe pernicious anemia

Low hemoglobin as a result of an iron deficiency due to the inability to absorb vitamin B-12

What are the causes of abnormal hemoglobins?

Thalassemias and sickle cell anemia

What is polycythemia?

Abnormal excessive RBCs

What are the bleeding disorders?

Thrombocytopenia (platelet deficiency) and hemophilia (hereditary bleeding disorder)

What is leukopenia?

Abnormally low WBC count

What is leukemia?

Overproduction of abnormal WBC’s- clones of single WBC that remain unspecialized and divide out of control, myelocytic leukemia, lymphocytic leukemia

What does infectious mononucleosis do?

It is a viral infection that increases mononuclear WBCs

Describe hemostasis

All the mechanisms that try to stop blood loss from a blood vessel (such as the vascular spasm, platelet plug formation, and coagulation)

Describe hemolysis

The process by which RBCs clump or are attacked/broken down, causing hemoglobin release. If massive this can lead to kidney failure

What is the role and timing of vasoconstriction?

This is triggered by a loss blood, which activates the sympathetic nervous system to constrict blood vessels, which acts protectively to slow blood flow to the injured area, allowing for the platelet plug to form. Vasoconstriction only lasts for 20-30 minutes and fades away to allow blood to flow again to the affected area

What mechanisms prevent platelet aggregation?

Intact endothelial cells release nitric oxide under normal conditions. Nitric oxide then causes blood vessels to vasodilate and prevents platelets from aggregating on blood vessel walls

What mechanisms promote platelet aggregation?

Collagen fibers get exposed to blood when blood vessels get damaged, and platelets stick to the collagen fibers and activate, causing other platelets to activate and adhere. This causes the release of increasing amounts of ADP, serotonin, and thromboxane A, which further enhance platelet aggregation through positive feedback mechanisms

What is the role of fibrinogen?

It plays a role in coagulation and secondary hemostasis, forming a fibrin mesh that stabilizes the platelet plug to keep it together

Describe primary hemostasis

Happens in small blood vessels (microvessels) that don’t have a lot of blood flow and the leak can be stopped by forming a platelet plug only. This plug will not get washed away by strong blood flow

Describe secondary hemostasis

This occurs in larger blood vessels with stronger blood flow and potential for blood loss. After platelet plug formation there is a coagulation step that involved fibrin cross-linking and clotting factor activation (eg thrombin)

What is embolus

A free floating clot that can get stuck in blood vessels and stop blood flow (cause ischemia)

What is a thrombus

a stationary blood clot that forms in an unbroken blood vessel

What RBC blood types will react against what other RBC blood types?

A Blood reacts against B and AB, B reacts against A and AB, O reacts against A, B, and AB, and AB does not react against anything

What do RH antigens cause in newborns, and what can that lead to?

They cause hemolytic anemia, which can lead to premature death or the fetus or of the infant after birth

How do Rh antibodies work?

Upon exposure to the opposite Rh blood type, anti-Rh antibodies are formed, and a transfusion reaction will occur the second time they are exposed

How does hemolytic anemia work?

During the first pregnancy, the Rh- mother gets exposed to Rh+ fetal blood, and the first infant is born unaffected. Then, in the second pregnancy, the Rh- mother has pre-formed RH antibodies that attack the fetus

Describe the flow of lymph through the body

Tissues into blood capillaries → interstitial spaces → lymphatic capillaries → lymphatic vessels → lymphatic trunks → lymphatic ducts → subclavian veins into venous system near the heart

What are the functions of the lymphatic vessels?

To provide a one-way system that moves lymph toward the heart where it will be returned to our circulatory system. Lymphatic capillaries are very permeable and take up fluid, debris, proteins, damaged cells including cancer cells in interstitial spaces between cells that has left the circulation. Lymphatic vessels have many inter-endothelial junctions which act as one-way valves preventing retrograde (away from heart) flow of lymph

What conditions control lymph flow into and out of lymph capillaries?

When interstitial fluid pressure is more than capillary fluid pressure, the flap opens and lymph enters lymphatic capillaries. When capillary fluid pressure is more than interstitial fluid pressure flaps close. Proteins freely enter through the gaps between cells

What are the function and location of lacteals?

Specialized lymphatic capillaries found in intestinal mucosal membrane, located in villi and absorb fat from our diet, the lymph in these vessels is called chyle

What are the primary lymph organs and their function?

They are the bone marrow and thymus, and their primary purpose is to make lymphocytes

What are the secondary lymph organs and their function?

Lymph nodes, spleen, tonsils, peyers patches (small intestine), and appendix. This is where lymphocytes get exposed to antigens and are activated

Lymph Node functions

Cleanse, filter lymph, immune system activation (T and B cells and macrophages hang out here)

Spleen function

Largest lymph organ, where lymphocytes proliferate, maintenance works in filtering blood and removing defective or aged cells

Thymus function

Lacks reticular tissue, site of T cell maturation, functions early in life up to puberty

MALT (muscosa-associated lymphatic tissue) function

Present in tonsils, appendix and areas open to the outside (like the intestines)

How does the lymph node function to cleanse lymph?

Macrophages in the lymph nodes remove debris and microorganisms to get rid of them so they are not returned back to our circulation (blood stream)

How does the lymph node function as a site of immune system activation?

T cells hang out in lymph nodes and wait to encounter antigens brough back by dendritic cells (antigen presenting cells)

What is the function of red and white pulp in the spleen?

White pulp is where immune functions occur, red pulp is where blood filtering takes place

What is the first line of defense in the immune system?

Barrier Function (skin, mucosal membranes), secreted protective chemicals (acidic substances, lysozymes, mucin, defensins) that inhibit bacterial growth/other microorganisms

What is the second line of defense in the immune system?

Only activated if outer barriers are breached and consists of phagocytic cells (nearby macrophages and migratory neutrophils), natural killer cells, inflammatory response, antimicrobial proteins, fever

What do interferons do?

slow down/prevent viral replication

What are complement proteins?

An inactive protein system in blood that becomes activated in response to things it encounters (antibody-antigen complexes, mucin on microbes, or spontaneously)

How does transferrin iron-binding work?

It slows down microbial growth by sequestering iron needed as a co-factor

What does the adaptive immune system include?

Third line of defense, humoral immunity, and cellular immunity

What does the third line of defense include?

It is activated later and often as a result of innate immune system activation, comes in if innate immune system needs back up. This system in antigen specific, systemic, and has memory

What does humoral immunity include?

B cell, antibody-mediated immunity

What does cellular immunity do?

T cell, T cells do effector functions

How fast does the innate system act?

Within minutes

How fast does the adaptive system act?

Within days

What is the order of processes from neutrophils to injury site?

Leukocytosis → margination → diapedesis → chemotaxis → after these steps microbes will be phagocytizes

What do natural killer cells do?

They quickly eliminate virally infected cells or cancer cells, kill infected target cells by secreting inflammatory cytokines that cause them to undergo apoptosis (programmed cell death), check cells for proper markers and if MHC class 1 is missing there is no inhibition, and the cell will be killed

What immune cells attack and eliminate infected cells?

T cells, Natural killer cells

What occurs at the site of injury?

The inflammatory response (redness, heat, swelling, and pain) which prevents spread of damaging agents, disposes of cell debris and pathogens, alerts adaptive immune system, and sets stage for repair

What are the four cardinal signs of an inflammatory response?

Redness, heat, swelling, pain

When injured stressed cells release inflammatory chemicals what happens?

They dilate arterioles, increase capillary permeability, and attract phagocytic cells

What does vasodilation do?

It allows for more blood flow to the injured area, more immune cells and other chemicals (redness + heat)

What does increased capillary permeability cause?

It allows for more fluid to go into the injured area, for cellular debris or foreign substances to be removed when fluid is taken up by the lymph system, and it allows necessary clotting fibers to come to the area (swelling + pain)

Describe the interferon response by infected cells

Cells that are infected with viruses secrete interferons. Usually, the infected cell grows lots of viruses and get lysed. Release of interferons however provides a warning signal to neighboring cells and causes them to turn on interferon-stimulated genes that make antiviral proteins that interfere with the virus life cycle and block their reproduction

What activates the complement system?

The classical pathway, lectin pathway, and alternative pathway

What is the classical pathway?

Antibody-antigen complexes

What is the lectin pathway?

Lectin on microorganism surface

What is the alternative pathway?

Spontaneous activation (no inhibitors present)

Describe complete antigens

immunogenicity and reactivity, stimulates B effector cells to make antibodies and these antibodies will react against this same substance, often larger more complex proteins

Describe incomplete antigens

Only reactivity, these do not stimulate the B effector cells to make antibodies, but they can react against antibodies that were not made specifically against it. These are often small proteins that can get stuck to bigger more complex proteins that may be able to generate an immune response and then could become a complete antigen

Where do B cells originate and mature?

They originate in the bone marrow and stay there to develop immunocompetence (ability to interact w/ spef antigen) but they are still naive. They then move to the lymphoid tissues to “seed,” which is where antigen challenge occurs. After encountering antigen, they are antigen-activated. These activated immunocompetent B and T cells recirculate in blood and lymph looking for antigen.

Where do T cells originate and mature?

Originate in the bone marrow (immature) and move to the thymus where they develop immunocompetence (ability to interact w/ a specific antigen) but are still naive (haven’t yet encountered their antigen), then travel to lymphoid tissues to “seed” where antigen challenge occurs. After encountering the antigen they are “antigen-activated.” Activated immunocompetent B and T cells recirculate in blood and lymph looking for antigen

What is the role of T lymphocytes?

They are part of cellular immunity (activated by APCs)

What are the primary and secondary types of T lymphocytes?

Primary- Helper, cytotoxic, and regulatory

Secondary- Memory

Describe Helper T lymphocytes

They activate B cells and amplify innate defenses

Describe cytotoxic T lymphocytes

They directly attack and kill other cells

Describe regulatory T lymphocytes

They dampen immune response (prevent autoimmune reaction)

Describe memory T lymphocytes

They allow faster activation next time an antigen is encountered

What is the role of B lymphocytes?

They oversee humoral immunity

What is the primary type of B lymphocytes?

Plasma cells

What is the secondary type of B lymphocytes?

Memory cells

How do plasma/effector cells work?

B cells proliferate into them and make a large number of antibodies, with antibody levels peaking 10 days post primary exposure, and 2-3 days post second exposure

How do memory cells work?

They are long lived and allow faster immune response to future infections with the same antigen

What are the two types of antigen presenting cells?

Macrophages and dendritic cells

What do macrophages and dendritic cells do?

They eat antigens and display antigen fragments on cell surface to activate T cells

What are the different ways to gain immunity?

Active Naturally acquired, active artificially acquired, passive naturally acquired, and passive artificially acquired

What is active immunity?

B cells encounter antigen and produce antibodies

What is passive immunity?

Ready-made antibodies introduced to the body