T-3 Flashcards
Baroreceptors
- Sensitive to blood pressure changes
* Send messages to the cardiac and vasomotor centers in the medulla of the brain
What happens when blood pressure increases?
- Cardiac center stimulates parasympathetic nerves that slow heart rate
- Vasomotor center INHIBITS sympathetic nerves that constrict blood vessels
- Blood pressure is reduced
Angiotensin
• Hormone that raises blood pressure
Angiotensin(tension-tight-raises pressure)
Aldosterone
- Helps regulate salt excretion
* Affects blood volume and blood pressure
Cardiac output (CO)
- Stroke volume times heart rate
* Stroke volume depends on venous return and on neural messages and hormones, especially epinephrine and norepinephrine
Starling’s law of the heart
• The more blood delivered to the heart by the veins, the more blood the heart pumps
The walls of arteries and veins are thick and do not allow materials to pass through; What three layers do they have?
tunica intima (the inner layer composed of endothelium),
tunica media (middle layer composed of connective tissue and smooth muscle)
tunica adventitia (outer layer composed of elastic and collagen fibers)
Compare the types of internal defense mechanisms (specific or not) in invertebrates and vertebrates
Non-specific defense mechanisms exist in invertebrates including phagocytes; chemical defense mechanisms are in sponges.
Vertebrates, have both non-specific and specific immune responses due to the specialized lymphatic system that can make antibodies due to lymphocytes.
Antigen
An antigen is any foreign material (it can be protein, nucleic acid, silicone, pollen, etc) recognized as non-self.
The 5 classes of immunoglobulins
G, A, M, E, D.
IgG
makes up 75% of the immunoglobulins
IgM
Along with IgG, defend against the major pathogens.
IgA
IgA is a surface-associated immunoglobulin and is found in mucus, tears, saliva and breast milk and prevents pathogens from attaching to the surface.
IgD
IgD is present in low concentrations and, with IgM, is involved in the functioning of B cells.
IgE
IgE is involved in allergies and parasitic infections and participates in release of histamine.
The three types of lymphocytes include
B, T, and natural killer (NK) cells.
T cells are responsible for
Cellular immunity originating from stem cells in the bone marrow but becoming immunocompetent in the thymus; they attack tumor cells and cells infected by pathogens.
Suppressor T cells
Suppressor T cells release cytokines that inhibit the B cells (and some T cells) from acting.
Contrast a secondary with a primary immune response
Primary immune response-
Stimulated by the first exposure to an antigen
Secondary immune response-
Stimulated by a second exposure to the same antigen
More rapid and more intense than the primary response
Compare active and passive immunity with examples.
Active immunity occurs following exposure to antigen either artificially (vaccination) or naturally (sickness).
Passive immunity is the receipt of antibodies rather than the body actually making them;
it may be either natural (baby receiving colostrum from nursing) or artificial (injection of antitoxin).
Graft rejection
Graft rejection is a result of the tissues and organs of the donor having different MHC antigens than the donee.
How does the body ward off cancer?
NK cells and cytotoxic cells produce interferons, interleukins, and TNF to ward off cancer.
AIDS risk factors
Risk factors include unprotected promiscuous sex regardless of whether it is homosexual, heterosexual, or bisexual and IV drug use.
Is a vaccine possible for AIDS?
A vaccine is nearly impossible since the virus encloses its genome into the body’s own cells and is difficult for the immune system to detect it .
Tumor necrosis factors (TNFs)
Kill tumor cells and stimulate immune cells to initiate an inflammatory response
Cytokines
Signaling proteins that regulate interactions between cells. (Cytokines- cyborg and signals)
Interferons
Inhibit viral replication and activate natural killer cells
Interleukins
Secreted by macrophages & lymphocytes (regulate interactions between lymphocytes)
Cause fever & have other widespread effects
Chemokines
Attract, activate, and direct the movement of certain cells of the immune system. Chemokines (Chemo-chemical Kin-family/closeness) attract by chemicals and family activates and directs them
The two types of non-specific immunity involving Cells
Phagocytes destroy bacteria
Neutrophils
Macrophages
Natural killer cells (NK cells)
Destroy cells infected with viruses
Destroy foreign or altered cells such as tumor cells
The two types of
Vertebrate specific defense
Antibody-mediated (also called humoral)
B-cells secrete antibodies
Cell-mediated
T-cells become Killer Ts and control B-cells
Steps in antibody-mediated immunity
Contact with antigen by a macrophage
Phagocytosis & Fragmentation of the antigen
Antigen placed on the surface of macrophage & T-helper cell aids in presenting processed antigen to B-cell
B-cells differentiate into clone of plasma cells and memory cells
Antibodies are produced
Human immunodeficiency virus (HIV)
Retrovirus
Causes acquired immunodeficiency syndrome (AIDS)
Destroys T helper cells
Severely impairs immunity
What does the lymphatic system do?
The lymphatic system returns interstitial fluid to the circulatory system, it also functions in immunity and adsorption of lipids from the gastrointestinal tract.
MHC stands for
Major HistoCompatibility-antigen. In humans, the MHC is the HLA group
HLA stands for
Human Leucocyte Antigen
Compare the advantages and disadvantages of gas exchange in air with those in water.
Gills are adapted for respiration in water and require lots of energy to extract oxygen from the water;
Trachea and lungs are adapted for terrestrial respiration but gas exchange must take place across a moist surface to prevent water loss in terrestrial organisms.
Describe the function of respiratory pigments.
Hemoglobin in vertebrate blood greatly increases the amount of oxygen which can be transported by the blood. It does this because of an iron-porphyrin (heme) bound to a protein (globin). The iron portion has a high affinity for oxygen.
Hemocyanins are copper-containing respiratory pigments in some mollusks and arthropods where the Cu acts to scavenge oxygen rather than Fe.