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What are the eight specialized cellular functions?
Movement, conductivity, metabolic absorption, secretion, excretion, respiration, reproduction, and communication
Adenosine Triphosphate (ATP)
Functions as an energy-transferring molecule. Energy is stored by molecules of carbohydrates, lipid, and protein, which when catabolized, transfer energy to ATP
What is oxidative phosphorylation and where does it occur?
It is the mechanism by which energy produced by fats, proteins, and carbohydrates is transferred to ATP and it occurs in the mitochondria
What are the four basic types of tissue?
epithelial, muscle, nerve, and connective tissue
What is neural tissue composed of?
Highly specialized cells called neurons that receive and transmit electrical impulses raidly across junctions called synapses.
Where is the most epithelial tissue and what is its' fiunction?
Epithelial tissue covers most internal and external surfaces of the body. The functions of epithelial tissue include protection, absorption, secretion, and excretion.
What is the function of connective tissue?
It binds various tissues and organs together, supporting them in their locations and serving as storage for excess nutrients
What is muscle tissue composed of? What is it's function when attached to bones vs in internal organs?
Muscle tissue is composed of long, thin, highly contractile cells or fibers called myocytes. Muscle tissue attached to bones enables voluntary movement. Muscle tissue in internal organs enables incoluntary movement (heartbeat)
What are genes and where are they located?
Genes are the basic units of inheritance and are composed of DNA. They are located on chromosomes
What is a mutation?
An inherited alteration of genetic material (DNA)
What are the substances that cause mutations?
What is transcription?
The process by which DNA specifies a sequence of messeger RNA (mRNA).
What is translation and where is it located?
The process by which RNA directs the synthesis of polypeptides. This process takes place in the ribosomes which consist of proteins and ribosomal RNA (rRNA)
What do human cells consist of?
Diploid somatic cells, and haploid gametes
How many pairs of chromosomes does a human have?
A human has 23 chromosomes, 22 are autosomes. The last pair is sex chromosomes, men XY, women XX
What is trisomy?
A type of aneuploidy in which one chromosome is present in three copies in somatic cells. A partial trisomy is one in which only part of a chromosome is present in three copies
What is down syndrome?
Trisomy 21, most well known, It affects 1 in 800 live births and is much more likely to occur in the offspring of women older than 35 years
What are the types of cellular injury?
- Cellular injury occurs if the cell is unable to maintain homeostasis.
- Reversible-cells may recover
- irreversible- cells die
- Injury can be caused by lack of O (hypoxia), free radicals, caustic or toxic chemicals, infectious agents, inflammatory and immune responses, genetic factors, insufficient nutrients, or physical trauma from many causes.
What are the four biochemical themes that are important to cell injury?
- ATP depletion
- ocygen and oxygen-derived free radicals
- intracellular calcium and loss of calcium steady state
- defects in membrane permeability
What is apoptosis?
a distinct type of sublethal injury, is a process of selective cellular self-destruction that occurs in both normal and pathologic tissue changes.
What is a benign tumor?
Usually encapsulated, well differentiated and do not metastasize
What is a malignant tumor?
Have more rapid growth rates, specific microscopic alterations (anaplasia and loss of differentiation), ansence of normal tissue organizatio, and no capsule; they invade into blood vessels and lymphatics and metastasize
What is a carcinoma?
Arise from epithelial tissue, sarcomas arise from connective tissue, lymphomas arise from lymphatic, and leukemia are cancers of blood forming cells.
What is carcinoma in situ?
preinvasive epithelial tumors of glandular or squamous cell origin
What is the difference between low staged cancers and stage 3 or 4?
- Low stage is localized cancer
- stage 3 is spread regionally
- stage 4 is spread distantly
How are cancer cells characterized?
By anaplasia, or loss of differentiation. Autonomy, or independence from normal cellular controls
What are tumor markers and where are they found?
They are substances (hormone, enzymes, genes, antigens, and antibodies) found in blood, urine, spinal fluid. They are used to screen and identify individuals at high risk for cancer, to help diagnose specific types of tumors and to follow the clinical course of caner.
What are undifferentiated cells in adults?
Cells that are not totally committed to a specific funtion are known as pluripotent cells, precursor cells, or stem cells. Cancer cells become more like embryonic cells and are less differentiated. Cancerous growth depends on derangements of cell differentiation.
What are the three main genetic mechanisms that have a role in human carcinogenesis?
- Mutation of genes resulting in hyperactivity of growth-related gene products (Oncogenes)
- mutation of genes resulting in loss or inactivity of gene products that normally would inhibit growth (tumor supressor genes)
- mutation of genes resulting in overexpression of products that prevent normal cell death (apoptosis), thus allowing continued growth of tumors.
What do epidemiologic and molecular data suggest about the pathways to produce cancer?
It takes five or six disinct mutations in different signaling pathways to produce cancer. Mutations activate growth-promotion pathways, block antigrowth signals, prevent apoptosis, turn on telomerase and new blood vessel growth (angiogenesis), and allow tissue invasion and distant metastasis
How do cancers metastasize?
Through veins and lymphatics, first regionally and then distantly. Most cancer cells are not capable of successful metastasis; however when it does occur it ogten pertains to a poor prognosis.
What are the steps for a successful metastasis?
Invasion, survival in the circulation, attachment, and growth, induction of angiogenesis at a favorable distant site are required. Both seed and soil must be matched for metastasis to occur.
What are the environmental factors that can alter the frequency and consequences of genetic mutations?
The most significant factors include smoking, radiation, obesity, a few oncogenic viruses, and helicobacter pylori.
What are the clinical manifestations of cancer?
Pain, fatigue, cachexia, anemia, leukopenia, thrombocytopenia, and infection
What are the two types of human defense?
- Innate resistance: natural barriers and inflammatory response
- adaptive (acquired) immune system
What is a mast cell?
The most important activator of the inflammatory response which initiates inflammation by releasing biochemical mediators (histamine and chemotactic factors) from preformed cytoplasmic granules and synthesizing other mediators (prostaglandins, leukotrienes) in response to a stimulus.
What is histamine and what releases it?
Histamine is the major vasoactive amine released from mast cells. It causes constriction of vascular smooth muscles, dilation of capillaries, and retraction of endothelial cells lining the capillaries, which increases vascular permeability
What cells are involved in the inflammatory process?
Neutrophils, monocytes, and macrophages, eosinophils, natural killer cells (NK), and platelets
What are the local manifestations of inflammation?
They are the result of the vascular changes associated with the inflammatory process, including vasodilation and increased capillary permeability. The symptoms include redness, swelling, heat and pain
What are the systemic manifestations of inflammation?
Fever and increased levels of circulating leukocytes and plasma proteins (acute phase reactants)
What is chronic inflammation?
It can be a continuation of acute inflammation that lasts 2 weeks or longer. It also can occur as a distinct process without much preceding acute inflammation.
What characterizes chronic inflammation?
A dense infiltration of lymphocytes and macrophages. The body may wall off and isolate the infection to protect against tissue damage by fomation of a granuloma.
What is adaptive immunity?
A state of protection, primarily against infectious agents, that differs from inflammation by being slower to develop, being more specific, and having memory that makes it much longer lived.
What is the difference between natural immunity and acquired immunity?
Innate resistance, and acquired immunity is gained after birth.
What are antigens?
molecules that react with components of the immune response, such as antibodies and receptors on B and T cells. Most antigens can induce an immune response and thus the antigens are also immunogens.
What is the purpose of self-antigens?
Antigens on an individual's own cells. The individual's immune system does not normally recognize self-antigens as immunogenic, a condition known as tolerance.
What is the humoral immune response?
It is provided by molecules (antibodies) produced by B cells.
What are antibodies?
Plasma glycoproteins that can be classified by chemical structure and biologic activity as IgG, IgM, IgA, IgE, and IgD
What are T cell responsible for?
Cell-mediated immune response
What are the types of mature T cells?
cytotoxic T cells (Tc), regulatory T cells including T helper (Th) and T suppression (Ts), and memory cells.
What does the major histocompatibility complex (MHC) do?
T cells have antigen specific receptors that must "see" antigen presented on cell surfaces by special antigen-presenting molecules of the major histocombatibility complex (MHC molecules)
What does the development of cell-mediated or humoral immune responses usually depend on?
Where and when are T and B lymphocytes produced?
The production of B and T lymphocytes with receptors against millions of antigens that will be possibly encountered in an individuals lifetime occurs in the fetus in the primary lymphoid organs: the thymus for T cells and portions of the bone marrow for B cells.
Where do immunocompetent T and B cells migrate?
From the primary lymphoid organs into the circulation and secondary lymphoid organs to await antigen
What is hypersensitivity?
An appropriate immune response misdirected against the host's own tissues (autoimmunity) or directed against beneficial foreign tissues, such as transfusions or transplants (alloimmunity); or it can be exaggerated responses against environmental antigens (allergy).
What are the mechanisms of hypersensitivity classified as?
- Type I: IgE mediated reactions
- Type II: Tissue-specific reactions
- Type III: immune-complex-mediated
- Type IV: cell-mediated reactions
What is the difference between immediate or delayed hypersensitivity reactions?
- Immediate: developing within seconds or hours
- delayed: developing within hours to days
What is anaphylaxis?
The most rapid immediate hypersensitivity reaction, is an explosive reaction that occurs within minutes of reexposure to the antigen and can lead to cardiovascular shock
Bacteria injure cells by producing endotoxins or endotoxins, what are they?
- Exotoxins: enzymes that can damage the plasma membranes of host cells or can inactivate enzymes critical to protein synthesis
- Endotoxins: activate the inflammatory response and produce fever
What is septicemia?
The proliferation of bacteria in the blood. Endotoxins released by blood-borne bacteria cause the release of vasoactive enzymes that increase the permeability of blood vessels. Leakage from vessels causes hypotension that can result in septic shock.
What do viruses that have invaded host cells do?
They may decrease protein synthesis, distrupt lysosomal membranes, form inclusion bodies where synthesis or viral nucleic acids is occurring, fuse with host cells to produce giant cells, alter antigenic properties of the host cell, and transform host cells into cancerous cells.
What is immunodeficiency?
The failure of mechanisms of self-defense to funtion in their normal capacity.
What are congenital immunodeficiencies?
They are caused by genetic defects that distrupt lymphocyte develoipment
What are acquired immunodeficiencies?
They are secondary to disease or other physiologic alterations
What is the clinical hallmark of immunodeficiency?
A propensity to unusual or recurrent severe infections. The type of infection usually reflects the immune system defect.
What is AIDS?
An acquired dysfunction of the immune system caused by a retrovirus (HIV) that infects and destroys CD4+ lymphocytes (helper T cells)
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