Medical Surgical A

Study Tips Frequent quizzes Understand the material Read the text Study frequently for short periods Find a study buddy

Classroom Etiquette and rules: Turn off cell phones Classroom Etiquette and rules: Turn off cell phones ! No chewing gums Be considerate of others: Take out what you bring in. Be ontime, No late more than 5-10m Talk to me, NOT your neighbor! No absence from exams without prior excuse Do not ask for grades over the phone or internet.

Academic Integrity Use Professional ethics NO: Plagiarism Cheating Allowing others to copy from you Penalties can be severe !!

Terminology Disease – loss of homeostasis, or when physical or mental capacities cannot be fully utilized (interuption, cessation or disorder in the function of an organ or system). Etiology = cause of the disease When the etiology is unknown, the disease is said to be idiopathic.

Categories of etiology Genetic disease– genes are responsible for a structural or functional defect Congenital disease– genetic information is intact, but the intrauterine environment interferes with normal development Acquired disease – disease is caused by factors encountered after birth (biological agents, physical forces, and chemical agents) Genetic - hemophilia

Clinical manifestations – indications that the person is sick Symptoms – unobservable effects of a disease reported by the patient Signs – observable or measurable traits Syndrome - a characteristic combination of signs and symptoms associated with a particular disease.

Diagnosis – identification of the specific disease Therapy – the treatment of the disease to either effect a cure or reduce the patient’s signs and symptoms Prognosis – prediction of a disease’s outcome

Understanding the cell

Structural Levels

Cell The cell is the building block of each living organism. Each cell is a self-contained system that undergoes the functions of energy production and usage, respiration, reproduction, and excretion

Cellular Functions Organization Metabolism Responsiveness Movement Catabolism Anabolism Responsiveness Conductivity Movement Reproduction Growth Differentiation Respiration Secretion Excretion

Pathophysiologic concepts The cell faces a number of challenges through its life. Stressors, changes in the body’s health, disease, and other extrinsic and intrinsic factors can alter the cells’ normal functioning. Adaptation Cells generally continue functioning despite challenging conditions or stressors. However, severe or prolonged stress or changes may injure or destroy cells. When cell integrity is threatened, the cell reacts by drawing in its reserves to keep functioning, by adaptive changes or by cellular dysfunction.

If cellular reserve is insufficient, the cell dies If cellular reserve is insufficient, the cell dies. If enough reserve is available and the body doesn’t detect abnormalities> The cell adapts by: atrophy, hypertrophy, hyperplasia, metaplasia, or dysplasia.

Cells change to adapt to their environment Atrophy = shrinkage = decrease in cell size. Reversible Due to : decreased use (disuse) decreased blood supply decreased nutrition denervation, or reduced endocrine stimulation Of tissues or organs may be due to cell shrinkage or due to cell death.

Atrophy  Size of organelles  Size of organelles  Workload (or disease state)  Efficiency -OR-  Functionality in disease state  Energy Usage

Hypertrophy an increase in the size of a cell due to an increased workload. It may be normal or abnormal. Hypertrophy is primarily seen in cells that cannot adapt to increased work by increasing their numbers through mitosis (cardiac and skeletal muscle cells).

There are three main types of hypertrophy: -Physiologic hypertrophy (i.e., increased muscle bulk through exercise). -Pathologic hypertrophy( hypertrophy of the left ventricle in response to longstanding hypertension) . -Compensatory hypertrophy (the loss of one kidney causes the cells of the remaining kidney to undergo hypertrophy).

Hypertrophy  Size  # of organelles  contractility  Size  Workload (or disease state)  Functionality in disease state  ability to meet demands! -OR-  contractility

Hyperplasia Hyperplasia, an increase in the number of cells, caused by increased workload/ hormonal stimulation. It can only occur in cells that undergo mitosis ( liver, kidney, and connective tissue cells). Hyperplasia may be: *Physiologic (monthly in uterine endometrial cells) . *Pathophysiologic (with excessive hormonal stimulation, which is seen in acromegaly) . *Compensatory (cells of a tissue reproduce to make up for a previous decrease in cells ; liver cells after surgical removal of sections of liver tissue).

 tissue size by  # of cells Hyperplasia  Workload Physiological state  rate of cell division  tissue size by  # of cells 2 types: Compensatory & Hormonal  ability to meet demands! ...  functionality

Hyperplastic endometrium

Metaplasia is the replacement of one adult cell with another adult cell that can better endure the change or stress. It’s usually a response to chronic inflammation or irritation; the change in the cells of the respiratory passages from ciliated columnar epithelial cells to stratified squamous epithelial cells in response to years of cigarette smoking. Stratified epithelial cells are better able to survive smoke damage. Unfortunately, they do not assume the vital protective role of ciliated cells.

Metaplasia Ex: Cigarette Pathological Smoking Normal Cells Abnormal Replacement

Dysplasia In dysplasia, deranged cell growth of specific tissue results in abnormal size, shape, and appearance.;adaptive and potentially reversible, they can precede cancerous changes. The most common sites of dysplasia are the respiratory tract (especially the squamous cells present as a result of metaplasia)and the cervix. Cervical dysplasia usually results from infection of the cells with the human papilloma virus (HPV). Dysplasia is usually rated on a scale to reflect its degree, from minor to severe.

Dysplasia Epithelial Pathological Tissue Mutation Normal Cells Abnormal Shape & Size Mutation

Cerical Dysplasia Normal Tissue Abnormal Tissue

Cell injury A person’s state of wellness and disease is reflected in the cells. Injury to any of the cell’s components can lead to illness. One of the first indications of cell injury is a biochemical lesion that forms on the cell at the point of injury. This lesion changes the chemistry of metabolic reactions within the cell. Consider, for example, a patient with HIV. The cells of the immune system may be altered, making the patient susceptible to infection.

Draw on your reserves, adapt, or die When cell integrity is threatened (toxins, infection, physical injury, or deficit injury), the cell reacts in one of two ways: • by drawing on its reserves to keep functioning • by adapting through changes or cellular dysfunction. If enough cellular reserve is available and the body doesn’t detect abnormalities, the cell adapts. If there isn’t enough cellular reserve, cell death (necrosis) occurs. Necrosis is usually localized and easily identifiable.

Mechanisms of Injury Hypoxic Chemical Structural Infectious (trauma…tons next semester!) Infectious Immunologic / Inflammatory

Toxic injury Toxic injuries may be caused by endogenous factors or exogenous factors. Common endogenous factors: genes, gross malformations, and hypersensitivity reactions. Exogenous factors include: alcohol, lead, CO, and drugs that alter cellular function. (i.e chemotherapy and immunosuppressants)

Infectious injury Viral, fungal, protozoan, and bacterial agents All can cause cell injury or death, through affecting cell integrity, by: interfering with cell synthesis, producing mutant cells. Ex. HIV virus alters the cell when the virus is replicated in the cell’s RNA Cell injury can have effects on the entire body Examples: fever, pain, tachycardia

Physical injury Results from a disruption in the cell or in the relationships of the intracellular organelles. Two major types of physical injury are” thermal (X ray, radiation Rx ) and mechanical either trauma or surgery( motor vehicle crashes, frostbite, and ischemia, abrasion, cutting, burns).

Deficit injury When a deficit of H2O, O2, or nutrients occurs, or if constant temperature and adequate waste disposal aren’t maintained, cellular synthesis can’t take place. A lack of just one of these basic requirements can cause cell disruption or death.

Hypoxic Injury Most Common Cause of Cellular Injury!  Atmospheric Oxygen  Respiratory Function Loss of Hb  Cardiovascular Function  Hb function (CO)  erythropoiesis Most Common Cause of Cellular Injury!

Hypoxia = deficiency in oxygen at cell Due to : Decreased oxygen in air Decreased hemoglobin or decreased oxygen transported to cells Diseases of the respiratory and/or cardiovascular system Ischemia is inadequate blood supply to a cell or tissue. Ischemia can cause hypoxia.

Consequences of Hypoxia NA diffuses into the cell and withdraw water Cell swell /burst production of lactic acid, decreased ph causes damage to the nuclear structures. The effects of hypoxia are reversible if oxygen is returned within time.

Clinical Manifestation Tachycardia, tachypnea, muscle weakness, and decreased LOC.

Complications Altered consciousness coma and death if prolonged cerebral (brain) hypoxia occurs. -Organ failure; ARDS, cardiac failure, or R. Rx:O2(atmospheric, mask, MV)

Temperature Extremes Very high temperatures can cause burn injuries (directly kill cells or indirectly by causing coagulation of blood vessels or the breakdown of cell membranes) . Very cold temperatures injures cells in two ways: --- = vasoconstriction (hypoxia & nutrients deficiency) = Formation of ice crystals in the cells (bursting). Prolonged exposure to the cold can lead to hypothermia.

Clinical Manifestation - Numbness or tingling of the skin or extremities. - Pale or cyanosis - cool to the touch. - Shivering early on, then lack of shivering as condition worsens. - Decreased LOC - Drowsiness, and - Confusion. Complications - Blood clotting, and gangrene. - Frostbite. - Ventricular dysrhythmia

Radiation Injury High energy ( ionizing radiation) like UV, X ray, nuclear weapons Low -energy (non-ionizing radiation). Ionizing radiation may injure or kill cells directly by destroying the cell membrane and causing intracellular swelling and cell lysis. Inflammatory response is stimulated (edema, white blood cell accumulation, and tissue scarring) It may also lead to mistakes in DNA replication or transcription which may cause programmed cell death or subsequent cancer . Most susceptible cells are cells that undergo frequent divisions (GIT, skin and hair, blood-forming cells and fetus). Ionizing radiation is emitted by the sun, in x-rays, and in. Non-ionizing radiation includes microwave and ultrasound radiation. The energy of this radiation is too low to break DNA bonds or damage the cell membrane.

Clinical Manifestations of Ionizing Radiation - Skin redness or breakdown. - With high doses, V & N - Cancer may develop years after the exposure . - Anemia.

Injury Caused by MO Cells may be destroyed directly by MO or by released toxins or as a result of the immune and inflammatory reactions . Clinical Manifestations Infection by bacteria and viruses, often results in: - Regional lymph node enlargement - Fever (usually low-grade with a viral infection) - Body aches - Skin rash or eruption, especially with viral infections - Site-specific responses, such as pharyngitis, cough, otitis media Rx: AB (C&S),antiviral

Cell aging By cell aging, cells lose structure (atrophy) and function (hypertrophy & hyperplasia). Cell aging may slow down or speed up, depending on the number and extent of injuries and the amount of wear and tear on the cell Causes:intrinsic/extrinsic S&Sx: decreases in elasticity of blood vessels, bowel motility, muscle mass, and subcutaneous fat.

Cell Death Necrosis; cell swelling and rupture of internal organelles as a result of prolonged hypoxia or inflammation. Apoptosis; cell shrinks on itself and then is engulfed by neighboring cells, may be caused by viral infection Deficiency in apoptosis leads to cancer Results of Cell Death; normal tissue, scar Gangrene; death of a large mass of cells wet Dry

Maintaining the balance Three parts of brain are responsible: the medulla oblongata (associated with vital functions, such as respiration and circulation), the pituitary gland (regulates the function of glands) the reticular formation (a group of nerve cells help control vital reflexes, such as cardiovascular function and respiration). Feedback mechanisms a negative feedback mechanism, works to restore homeostasis by correcting a deficit within the system a positive feedback mechanism, occurs when hormone secretion triggers additional hormone secretion.

Disease stages Incubation period. Prodromal period. Exposure or injury. Incubation period. Prodromal period. Acute phase (full intensity and complications commonly arise). Remission. This second latent phase occurs in some diseases, may be followed by another acute phase. Convalescence (rehabilitation) Recovery (regains health or normal functioning)