Cellular Regulation

Apoptosis

- Active programmed death of a cell - Triggered by abnormal cell development, excessive cell numbers, cellular injury, or simply the age of the cell - Cells self-destruct and disintegrate, eventually being engulfed by phagocytes. - Body uses energy during apoptosis and inflammation does not occur.​

Necrosis

- The passive death of a cell due to irreversible damage (rather than an active programmed cellular event) - Damage to the cell most often occurs b/c of injury - Because the cells undergo lysis, inflammation occurs with necrosis.

Steps of Tissue Repair after Injury

1. Inflammation - When blood vessels bleed upon injury, inflammatory chemicals are released within the area that is injured. - Nearby blood vessels dilate in order to allow various materials into the injured area (fluid, white blood cells, clotting proteins). - As the injured area begins to clot, the surface becomes dry and forms a scab. The signs of inflammation are redness, pain, swelling, and heat. 2. Proliferation - Blood supply is restored to the injured area once the clot is replaced by granulation tissue (new connective tissue and associated blood vessels that form during wound healing). - As fibroblasts begin to produce collagen fibers, macrophages begin to migrate to the area and engulf (eat) cellular debris or damaged/dead cells. - Epithelial cells then begin to multiply and migrate over the granulation tissue. 3. Maturation - Fibrosed area matures and begins to contract - Regenerated epithelium begins to thicken - Results in fully regenerated epithelium with underlying scar tissue

Cellular Response to Hypoxic Injury​

1. The cells produce less adenosine triphosphate (ATP) used for energy 2. Without ATP, the sodium-potassium pump stops working, allowing sodium and water to move into the cell. The cell swells, leading to changes in the cell membrane.​ 3. Anaerobic (without oxygen) glycolysis begins producing ATP. This leads to a build-up of lactic acid in the cell (acidosis). 4. Increased pH = destruction of proteins and enzymes within the cell. Up to this point, damage can be reversed if the oxygen supply resumes. If oxygen is not available, the cell will die. - Infarction = an area of cells that have died due to hypoxemia. If enough cells in one area die, the loss of function in tissues or organs can be serious. For example, when an area of cardiac muscle dies, it no longer contracts to pump blood.​

An older adult has been living with chronic, untreated high blood pressure (hypertension) and arthritis for the past 15 years.​ Question 3 / 4 Which method will most accurately diagnose cellular adaptation, such as hypertrophy?​ A. Microscopy B. Direct observation​ C. Blood test​ D. Radiography​

A Microscopy will most accurately diagnose altered cellular regulation.​ Blood tests can measure changes in levels of substances, such as electrolytes or troponin, in the blood due to altered cellular regulation.​ Radiography, or x-rays, makes tissue enlargement visual. For example, an enlarged heart could be due to hypertrophy of the cardiac muscle cells.​ Direct observation of skeletal muscles occurs after weight training.​

An older adult has been living with chronic, untreated high blood pressure (hypertension) and arthritis for the past 15 years.​ Question 2 / 4 Which factor most likely contributed to the cellular alteration?​ A. Blood pressure​ B. Older age​ C. Osteoarthritis​ D. Gender

A The client's high blood pressure, which has not been treated for the past 15 years, has increased the work of the cardiac muscle, leading to hypertrophy.​ Being an older adult is more likely to contribute to atrophy due to cellular aging.​ The changes due to arthritis in this client are unlikely to have caused the changes to the cardiac muscle.​ The gender of the individual was not included, so there is not enough information to support that as the most likely reason for changes in the heart.​

A young adult who wants to prevent cellular changes that cause disease should make which changes in their lifestyle choices? Select all that apply.​ A. Stay current with immunizations​. B. Participate in health screenings​. C. Exercise regularly​. D. Complete recommended physical therapy​. E. Eat more fresh fruits and vegetables​.

A ,C ,E A young adult interested in primary prevention should eat more fresh fruits and vegetables, exercise regularly, and stay current with immunizations.​ Participating in health screenings is a secondary prevention strategy that will help identify disease early. Physical therapy is used to help people with serious alterations in health maintain an optimal level of functioning (tertiary prevention).​

Which intracellular functions are negatively impacted by cellular hypoxia? Select all that apply.​ A. Sodium-potassium pump​ B. Cell membrane​ C. Energy production​ D. pH balance​ E. Anaerobic glycolysis​

A, B, C, D In the presence of decreased or absent oxygen, the cells experience hypoxia. Cellular functions that are negatively impacted include the sodium-potassium pump, which normally keeps the sodium and potassium balance correct, energy production stops, leaving the cell without a ready source of energy, lactic acid accumulates in the cell causing the pH to fall, and the cell membrane changes as a result of intracellular fluid increases.​ Anaerobic glycolysis begins as the energy sources decrease, so this system begins to work as expected due to hypoxia. Unfortunately, the lactic acid produced by this process is harmful to the cells.

Which facts about a person indicate they are at risk of altered cellular regulation? Select all that apply.​ A. Poor nutritional intake​ B. Exposure to nuclear material​ C. Genetic mutations​ D. Tobacco use​ E. Older adult​

A, B, C, D, E Risk factors for altered cellular metabolism include age (risk increases with age), genetic mutations (inherited or occurring within the body), tobacco use, poor nutritional intake, and exposure to pollution (e.g., radiation, nuclear material, air pollution, noise pollution, water pollution).​

Abnormal metabolites (cell damage)

Abnormal Metabolites​ Definition: accumulation of toxic compounds inside the cells leading to destruction​ Causes: genetic defects or inborn errors of metabolism​ Example: phenylketonuria (PKU)​

A caregiver who takes their children to receive immunizations before starting school is practicing which type of prevention?​ A. Responsible B. Primary C. Tertiary D. Secondary

B The goal of primary prevention is to maintain a healthy lifestyle to prevent the cellular changes that result in disease. Immunizations are a primary prevention strategy that strengthens the body's immune system to lessen the severity of a specific illness. The goal of secondary prevention is to recognize disease quickly so changes can be made to reduce the impact of disease on the body. The goal of tertiary prevention is to help individuals with serious alterations in health to maintain an optimal level of function and improve their quality of life. Responsible prevention is not a recognized level of prevention, though being responsible for one's health is desirable.

An older adult has been living with chronic, untreated high blood pressure (hypertension) and arthritis for the past 15 years.​ Question 1 / 4 What is the most likely type of cellular adaptation in the client's heart muscle? ​ A. Atrophy B. Anaplasia C. Hypertrophy D. Hyperplasia

C Hypertrophy, or enlargement of the cells without an increase in number, is caused by overworking the tissue or hormonal secretions.​ Anaplasia is a condition in which cells are undifferentiated, have variable cell structures, and many miotic fibers. The cause of anaplasia is related to chronic irritation or infection, not overuse. Hyperplasia refers to an increase in the number of cells of normal size caused by a compensatory mechanism or pathology, such as cancer. ​Atrophy is a decrease in the size of cells due to reduced use, poor nutrition, or aging.​

Which of the following tissue types does NOT easily regenerate when its cells are damaged? A. Bone B. Blood vessels C. Neurons D. Muscle E. Skin

C Nervous tissue or neurons do not have the ability to regenerate or get replaced if they get damaged.

A woman who is planning to become pregnant is taking folic acid to support healthy neurologic development of the fetus once she becomes pregnant. Which level of prevention is she practicing?​ A. Secondary B. Tertiary C. Primary

C Since folic acid promotes a healthy neurologic system during fetal development, this is an example of primary prevention.​ The goal of primary prevention is to maintain a healthy lifestyle to prevent the cellular changes that result in disease. The goal of secondary prevention is to recognize disease quickly so changes can be made to reduce the impact of disease on the body.​ The goal of tertiary prevention is to help individuals with serious alterations in health to maintain an optimal level of function and improve their quality of life.​

A person with cardiac disease who eats healthy food, takes medications as prescribed, and attends cardiac rehabilitation is practicing which level of prevention?​ A. Secondary B. Primary C. Tertiary

C This person is practicing tertiary prevention. Remember that primary (eating healthy) and secondary (taking medications) prevention measures are also part of tertiary (attending cardiac rehabilitation) prevention as they will strengthen the body by preventing or slowing further deterioration of the pathophysiologic changes in the body.​

Cellular Adaptation

Cellular adaption refers to the cell's ability to change in response to internal (lack of nutrients or oxygen and genetic variations) and external environmental (pollution, trauma, stress) threats.

Cellular Metabolism

Cellular metabolism is the sum of all chemical changes that take place in a cell through which energy and basic components are provided for essential processes, including the synthesis of new molecules and the breakdown and removal of others.

During wound healing or tissue repair, the job of macrophages is to ___________. A. stimulate epithelial cells to multiply B. release hormones in the area to increase blood flow C. produce and secrete collagen fibers D. phagocytize cellular debris E. aid in the formation of a scab

D All macrophages are cells that engulf (eat, digest) pathogens, cellular debris, or old/dead cells.

An older adult has been living with chronic, untreated high blood pressure (hypertension) and arthritis for the past 15 years.​ Question 4 / 4 Which level of prevention could have identified the main cause of this client's altered cellular regulation so changes could be made to maintain health?​ A. Tertiary B. Primary C. Quaternary D. Secondary

D The goal of secondary prevention is to recognize disease quickly so changes can be made to reduce the impact of disease on the body.​ The goal of primary prevention is to maintain a healthy lifestyle to prevent the cellular changes that result in disease.​ The goal of tertiary prevention is to help individuals with serious alterations in health to maintain an optimal level of function and improve their quality of life.​ There is no quaternary level of prevention.​

Atrophy

Definition: a decrease in the size of cells leading to reduced tissue mass​ Causes: reduced use, poor nutrition, decreased hormonal or neurological stimulation, aging​ Example: muscles get smaller and become weak when not used, such as after being in a cast

Fluid or electrolyte imbalance (cell damage)

Definition: abnormal levels of fluid or electrolytes within the cell​ Causes: can occur with any type of cellular injury​ Example: intracellular edema (excess fluid) resulting from cellular hypoxia

Hyperplasia

Definition: an increase in the number of cells leading to an enlarged tissue mass​ Causes: may be a compensatory mechanism or pathologic due to hormonal imbalance​ Example: occurs with hypertrophy during pregnancy to enlarge the uterus​

Hypertrophy

Definition: an increase in the size of cells leading to an enlarged tissue mass​ Causes: overworking the tissue, hormonal stimulation​ Example: increase in muscle size achieved by exercise​

Anaplasia

Definition: cells that are undifferentiated, have variable cell structures, and many miotic figures​ Causes: most often seen in malignant (cancerous) tumors​ Example: seen in aggressive tumors with rapid proliferation (growth) of immature cells​

Dysplasia

Definition: change in the size, shape, and reproduction of cells​ Causes: chronic irritation or infection, precancerous changes​ Example: changes in cervical cells that indicate cervical cancer may occur

Thermal Agents (cell damage)

Definition: damage from heat or cold​ Causes: impaired blood flow to cells, altered metabolic process in the cells​ Example: frostbite and sunburn​

Ischemia (cell damage)

Definition: decreased oxygen reaching the cells, tissues, or organs​ Causes: locally due to blocked blood flow; systemically due to low oxygen levels in the blood​ Example: myocardial infarction (heart attack)​

Chemical Toxins (cell damage)

Definition: exogenous (environmental) or endogenous (in the body) toxins may alter cell membrane permeability or the production of free radicals​ Causes: pollution, stress, some medications​ Example: medications to treat cancer (chemotherapeutics) are targeted to harm rapidly dividing abnormal cells​

Neoplasia

Definition: means new cell growth and usually refers to cancer​ Causes: various stimuli result in changes within the DNA structure of the cell​ Example: melanoma (skin cancer)

Microorganisms (cell damage)

Definition: microscopic organisms may cause pyroptosis, a type of cell death resulting from lysis of the cell resulting in inflammation​ Causes: bacteria, viruses, and parasites​ Example: an infected wound​

Mechanical Damage​ (cell damage)

Definition: pressure from an external force​ Causes: impaired blood flow, altered metabolic process in the cells​ Example: injury (bruise) to the arm when hit by a baseball bat​

Metaplasia

Definition: replacement of a mature cell type with another mature cell type​ Causes: vitamin A deficit, adaptive mechanism to prolonged irritation​ Example: replacement of ciliated columnar epithelium with squamous epithelium in the airways of smokers​

Fibrosis (tissue repair)

Fibrosis is the process of scarring after wound healing. This occurs when connective tissue replaces any type of damaged/injured/destroyed tissue to the point that remodeling occurs in excess and leads to the formation of scar tissue. Unlike regeneration fibrosis typically means that the original tissue function is lost.

Radiography or X-rays (diagnosing altered cells​)

Make tissue enlargement visual, such as an enlarged heart due to hypertrophy of the cardiac muscle cells.

Blood Tests (diagnosing altered cells)

Measure changes in levels of substances, such as electrolytes or cardiac enzymes, in the blood due to altered cellular regulation.

Regeneration (tissue repair)

Regeneration is the process of restoration or growth of cells or tissue, whereby the same tissue replaces damaged/injured/destroyed tissue. Once damaged tissue is replaced by new and healthy tissue, the original function of the tissue is restored.

Direct Observation (diagnosing altered cells​)

Skeletal muscles after weight training

Diagnosing Altered Cellular Regulation​

​​​​To most accurately diagnose altered cellular regulation, the cells must be examined using a microscope (microscopy) to see what changes have occurred. Other tests are used to help diagnose the disease caused by altered cellular regulation.