Pathophysiology chap 5

cell

functional and structural unit in the human body

outer plasma membrane

-enclosing fluid cytoplasm or intracellular fluid -semi-permeable, controlling passage of materials into and out of the cell

• maintains the cell's shape

nucleus

-consists of DNA

• genetic material controls the particular cell's function and structure, enclosed in the nuclear membrane

cytoplasm

-contains various nutrients, proteins, glucose, & electrolytes required for cell metabolism -other structures: ribosomes,lysosomes,Golgi complex, mitochondria

Ribosomes

granules that produce proteins

Mitochondria

-providing energy in the form of ATP for cell activities

Lysosomes

containing digestive enzymes, to break down unwanted materials

Golgi complex

process and release proteins

Organelles are

have many metabolic functions: -synthesis of protein or transport of cell products and wastes outside cell membrane.

plasma membrane

• includes special protein molecules or receptors for substances such as hormones, chemical transmitters, or drugs

• affect the cell's function

Regulator genes

-control mitosis for different types of cells

Epithelial cells

-replicate very rapidly because of the demand for replacement caused by constant "wear and tear" on surface tissues

Apoptosis

programmed cell death cells undergo

neoplasm or tumor

-cellular growth that is no longer responding to normal body controls

• unable to function as normal tissue cells because they consist of Atypical (abnormal) or immature cells

chondro

cartilage

carcinoma

epithelial tissue

sarcoma

connective tissue

oma

indicates a benign tumor, e.g., lipoma

Oncology

study of tumors -known as cancer

Benign tumors

-consist of differentiated cells that reproduce at a higher than normal rate

• often encapsulated and expands but does not spread

• freely moveable on palpation -not life threatening unless it is in an area such as the brain where the pressure effects

malignant tumors

made up of undifferentiated, nonfunctional cells that do not appear organized -cells tend to reproduce more rapidly than normal and often show abnormal mitotic figures.

• have lost cellular connections with each other, and reproduction is not inhibited

Benign: Cells: Similar to normal cells -Differentiated -Mitosis fairly normal Growth: Relatively slow

• Expanding mass -Frequently encapsulated Spread: Remains localized Systemic effects:Rare Life-threatening: only in certain locations (e.g., brain) Malignant Tumors: Cells: Varied in size and shape with large nuclei

• Many undifferentiated -Mitosis increased and atypical Growth:Rapid growth -Cells not adhesive, infiltrate tissue -No capsule Spread: Invades nearby tissues or metastasizes to distant sites thru blood & lymph vessels

benign vs malignant

Tumor cells

infiltrate or spread into surrounding tissue and may easily metastasize or break away to spread to other organs and tissues -often secrete enzymes such collagenase, which break down protein or cells, adding to the destruction and facilitating the tumor's spread into adjacent tissue. Systemic effects: Often present Life-threatening: Yes, by tissue destruction and spread of tumors

tumor

-enlarging space-occupying mass composed of more primitive or dysplastic cells

Malignant cells

-do not adhere to each other but often break loose from the mass, infiltrating into adjacent tissue

Inflammation and the loss of normal cells

lead to a progressive reduction in organ function

Tumor mass enlarges

-inner cells are frequently deprived of blood and nutrients and die.

angiogenesis

development of new capillaries in the tumor, thus promoting tumor development

Situ

neoplastic cells in a preinvasive stage of cancer that may persist for months or years

1. Unusual bleeding or discharge anywhere in the body.

2. Change in bowel or bladder habits (e.g., prolonged diarrhea or discomfort).

3. A change in a wart or mole (i.e., color, size, or shape).

4. A sore that does not heal (on the skin or in the mouth, anywhere).

5. Unexplained weight loss.

6. Anemia or low hemoglobin, and persistent fatigue.

7. Persistent cough or hoarseness without reason.

8. A solid lump, often painless, in the breast or testes or anywhere on the body.

WARNING SIGNS OF CANCER

1. Pain 2.Obstruction 3.Tissue necrosis and ulceration

Local effects of tumors (3)

Pain

-occurs when the tumor is well advanced -a warning of a problem -helpful if it occurs early, but this is rare -caused by direct pressure of the mass on sensory nerves -Inflammation also contributes -Secondary causes: infection, ischemia, and bleeding

Obstruction

-result when a tumor compresses a duct or passageway from an external position or grows inside a passageway or around a structure -cause serious complications for the patient

Tissue necrosis and ulceration

-lead to infection around the tumor

1.Weight loss and cachexia (severe tissue wasting) 2.Anemia or decreased hemoglobin 3.Severe fatigue 4. Infections 5.Bleeding 6.Paraneoplastic syndromes

Systemic Effects of Malignant Tumors

Weight loss and cachexia (severe tissue wasting)

-occur w/many malignancies -Contributing factors include anorexia, fatigue, pain, stress, and the increased demands placed on the body by reproducing tumor cells (nutrient trapping),

Anemia or decreased hemoglobin

decreases the oxygen available to cells, leading to fatigue and poor tissue regeneration

Severe fatigue

caused by inflammatory changes, cachexia, anemia, stress, and treatment schedules

Infections

-such as pneumonia occur frequently as host resistance declines

Bleeding

erode the blood vessels or cause tissue ulceration

Paraneoplastic syndromes

additional problems associated with certain tumors, such as bronchogenic carcinoma in the lungs

1. Blood tests 2.Tumor markers

2. X-ray, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT) scans 4.Cytologic tests

types of tests used for the diagnosis of cancer:

Tumor markers

-substances, enzymes, antigens, or hormones, produced by some malignant cells and circulating in the blood or other body fluid -eg.carcinoembryonic antigen (CEA) for colon cancer, human chorionic gonadotropin (hCG) for testicular cancer, alpha-fetoprotein (AFP) for hepatocellular cancer, CA125 for ovarian cancer, and prostate specific antigen (PSA) for prostate cancer.

X-ray, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT) scans

methods of examining changes in tissues or organs

Cytologic tests

• Histologic and cytologic examinations are used to evaluate biopsies of suspicious masses and check sloughed cells in specific tissues (exfoliative cytology).

Tumors

spread by one or more methods depending on the characteristics of the specific tumor cells -produce secondary tumors that consist of cells identical to the primary (parent) tumor

1. Invasion 2.Metastasis 3.Seeding

three basic mechanisms for the spread of cancer:

Invasion

-local spread, which the tumor cells grow into adjacent tissue and destroy normal cells -cancer in latin =crablike

Metastasis

-spread to distant sites by blood or lymphatic channels. -tumor cells erode into a vein or lymphatic vessel -travel to body then lodge in a hospitable environment to reproduce and create one or more secondary tumors -first appears in the regional lymph nodes, which localize the tumor cells for a time

Micrometastases

-missed, particularly in cancers that are known to spread at an early stage (e.g., breast cancer)

Seeding

-spread of cancer cells in body fluids or along membranes, usually in body cavities

T- Size of tumor N- Involvement of lymph nodes M- Presence of metastasis

Stages of Cancer

stage I tumors

-small & well localized, easy to treat, & have a good prognosis

stage IV tumors

-advanced, difficult to treat at multiple sites -poorer prognosis

1. Carcinoma in situ— noninvasive 2.Cervix-invasive carcinoma 3.Vagina involved 4.Widespread invasion

Invasive carcinoma of the cervix

1. Primary tumor 2.Lymph node 3.Vein 4.Tumor cells lodge in hospitable capillary bed

2. Secondary tumor grows& spreads

3. Multiple tumors

Metastatic breast cancer.

1. Primary breast cancer

2. Spread to axillary lymph node

3. Follow lymphatic to vena cava

4. Lung metastasis- secondary

5. Aorta carries tumor cells from lungs to all organs

6. Ovary metastasis -Liver metastasis -Brain metastasis

Metastatic breast cancer Arterial route

Carcinogenesis

process by which normal cells are transformed into cancer cells

Malignant tumors

-develop from a sequence of changes over a relatively long period of time -specific cancers have well-established risk factors (e.g., bronchogenic carcinoma or lung cancer and cigarette smoking)

Exposure to radiation

-lead to leukemia -ultraviolet radiation (sun) leads to skin cancer

Promoters

include hormones & environmental chemicals.

1. INITIATING FACTORS or PROCARCINOGENS -cause the first irreversible changes in the cell DNA

2. Exposure to PROMOTERS- later causes further changes in DNA, resulting in less differentiation & an increased rate of mitosis

3. Continued exposure and changes in DNA- result in a malignant tumor 4.Changes in the regulation of growth result in cells - capable of detaching from the tumor and spreading to distant sites (metastasis)

Stages in carcinogenesis

aggressive

Tumors that metastasize readily and exhibit cells that reproduce quickly are described

1. Primary ovarian tumor

2. Continuous peritoneal membrane

3. Secondary liver tumor

Ovarian cancer spread by seeding throughout the peritoneal cavity

1. Irreversible mutation of DNA

2. Repeated exposure to carcinogens. Additional risk factors (PROMOTERS)

3. Additional changes to DNA and cell structure (CANCER)

Multistage carcinogenesis. in carcinogens

1. Mutant cell- Possible intervention by DNA-repair genes

2. Membrane changes- Possible immune surveillance and destruction of mutant cell

3. Malignant cell

Multistage carcinogenesis in cell

Free radicals

-form in cells from exposure to radiation or certain products from metabolic processes

Cancer suppressor genes

inhibit neoplastic growth -seen as "foreign."

1.cell-mediated 2.humoral immunity

immune response 2 parts

Cytotoxic T lymphocytes, natural killer (NK) cells, and macrophages

involved in immune surveillance and the destruction of "foreign" or abnormal cell

Temporary or long-term immunodeficiency

increase the risk of cancer

-surgery -chemotherapy -immunotherapy radiation

• combination depending on the specific cancer

Basic treatment measures for cancer

Solid tumors

-frequently removed by surgery

Immunotherapy

stimulates the patient's immune system to target the cancer and attack it

Curative - tumor small & localized Palliative -cancer is advanced

Immunotherapy treatment:

Adjuvant therapy

-additional prophylactic treatment used in cancers that are known to metastasize early in their development, producing secondary tumors are too small to be detected (micrometastases)

Chemotherapy and radiation therapy

-administered in repeated doses at intervals that maximize tumor cell death but minimize the effects on normal tissues

1. Tumor growth

2. Signs appear

3. Diagnosis

4. Early surgery 5.Radiation Chemotherapy

5. Cure key: -Development of tumor before treatment -Progress of tumor after treatment -Size of malignant tumor

effects of treatment on a solid tumor

Surgery

-removal of the tumor and surrounding tissue, including the nearby lymph nodes if required -minimizes tissue damage and improves recovery time for the patient.

radiofrequency ablation (RFA)

-alternative to surgery for small single tumors in lungs or liver

• process is less invasive, easier for the patient to tolerate, and does not require the loss of an entire lobe of the organ as may happen with surgery

Radiotherapy

-causes mutations or alterations in the targeted DNA

• preventing mitosis or causing immediate cell death

Radiation

-damages blood vessels, cutting off blood supply to the tumor cells & starving them

• destroys the more rapidly dividing cells in the body, both tumor cells and normal cells (radiosensitive cells)

• used before surgery to shrink a tumor or destroy loose surface cells

Ionizing radiation

-consists of either electromagnetic waves such as x-rays or gamma rays

-External sources -Internal insertion

several methods of administration

External sources

-such as a cobalt machine, deliver radiation for a short period of time to a specific site in the body

Internal insertion

-radioactive materials at the tumor site may be used to treat specific cancers such as cervical or oral tumors

• accomplished by sealing the radioisotope (e.g., radium) in a "seed" or needle & implanting device

Brachytherapy

-used to treat breast cancer in the early stages when radioactive material is implanted in surrounding tissue following removal of the tumor

instill a radioisotope

-solution in a body cavity, such as the pleural cavity, to control excessive inflammatory exudate or blood from the tumor

Precautions

required when clients have internal sources of radiation to minimize radiation exposure of other persons

Adverse effects of radiation

-depend on the dose and extent of penetration of radiation into the body

1. Bone marrow depression

2. Epithelial cell damage

3. Abdominal radiation

Effects of radiation

Bone marrow depression

-most serious negative effect

• Decreased leukocytes greatly increase the risk of infection, decreased platelets may cause excessive bleeding, and decreased erythrocytes contribute to fatigue and tissue breakdown

Pneumonia and septicemia

common life threatening complications because body defenses are reduced

Epithelial cell damage

includes damage to blood vessels (vasculitis) and skin. Skin becomes inflamed (as in a sunburn), and hair loss (alopecia) occurs. -mucosa of the digestive tract is damaged -inflammation and ulceration in the digestive tract lead to bleeding

head or neck radiation

-become ulcerated, and xerostomia (dry mouth)

Abdominal radiation

-likely to damage the ovaries or testes, leading to sterility or the risk of teratogenesis

radiation

-often produces a nonspecific fatigue & lethargy accompanied by mental depression

Long-term effects of radiation

-inflammation, necrosis, and scar tissue -scar tissue may cause adhesions or obstruction and other secondary problems

antineoplastic drug

-Some types of cancer cells respond well

Chemotherapy

used alone (as in leukemias), or may be combined with surgery or radiation