Chapter 3: Altered Cellular and Tissue Biology Flash Cards

Play Memory | Create Card File | Append to Card File
Title: Chapter 3: Altered Cellular and Tissue Biology
Description: Understanding Pathophysiology 4th Edition by Huether and McCance
Number of Cards: 550
Save Count: 9
Author: dana75829
Created: 2009-09-05
Tags: altered and biology cellular nursing pathophysiology tissue
Private No

Save Count represents the number of people who have saved this card set to their flashcard list. Consider this an endorsement!

    • Question
    • Answer
    • Side 3
    • What can altered cellular and tissue biology result from?
    • (1) adaptation
      (2) injury
      (3) neoplasia
      (4) aging
      (5) death
    • What does adaptation occur in response to?
    • both normal, or physiologic, conditions and adverse, or pathologic, conditions
    • What is injury classified as?
    • (1) chemical
      (2) hypoxic (lack of sufficient oxygen)
      (3) free radical
      (4) intentional
      (5) unintentional
      (6) immunologic
      (7) infection
      (8) inflammatory
    • How is cellular death confirmed?
    • by structural changes seen when cells are stained and examined under a microscope
    • What does cellular aging cause?
    • structural and functional changes that eventually may lead to cellular death or a decreased capacity to recover from injury.
    • Why do cells adapt to their environment?
    • to escape and protect themselves from injury
    • What are the most significant adaptive changes in cells?
    • (1) atrophy (decrease in cell size)
      (2) hypertrophy (increase in cell size)
      (3) hyperplasia (increase in cell number)
      (4) metaplasia (reversible replacement of one mature cell type by another less mature cell type)
    • Is dysplasia (deranged cellular growth) considered a true cellular adaptation?
    • no, it is considered an atypical hyperplasia
    • What is atrophy?
    • a decrease or shrinkage in cellular size
    • What happens if atrophy occurs in a sufficient number of an organ's cells?
    • the entire organ shrinks and becomes atrophic
    • Atrophy can affect any organ but where is it most commonly seen?
    • (1) skeletal muscle
      (2) the heart
      (3) secondary sex organs
      (4) the brain
    • When does physiologic atrophy occur?
    • during early development

      for example, the thymus gland undergoes physiologic atrophy during childhood
    • Why does pathologic atrophy occur?
    • it occurs as a result of decreases in workload, pressure, use, blood supply, nutrition, hormonal stimulation, and nervous stimulation
    • What is disuse atrophy?
    • a type of skeletal muscle atrophy exhibited by individuals who are immobilized in bed for a prolonged time
    • What does aging cause in reference to atrophy?
    • causes brain cells to become atrophic and endocrine-dependent organs, such as the gonads, to shrink as hormonal stimulation decreases
    • How does an atrophic muscle cell differ from a regular muscle cell?
    • it has less endoplasmic reticulum and fewer mitochondria and myofilaments (part of the muscle fiber that controls contraction) than does the normal cell
    • What happens in muscular atrophy caused by nerve loss?
    • oxygen consumption and amino acid uptake are immediately reduced
    • List the possible mechanisms of atrophy.
    • (1) decreased protein synthesis
      (2) increased protein catabolism
      (3) or both
    • What does protein catabolism involve?
    • proteosomes and ubiquitin-proteosome pathway
    • What are proteosomes?
    • a large protein catabolic complex in the cytoplasm
    • What is the ubiquitin-proteosome pathway?
    • a pathway where proteins are degraded first to ubiquitin (another small protein) and then degraded in the cytoplasm
    • What plays a central role in controlling protein turnover?
    • protein ubiquitination and proteolysis
    • What does the deregulation of the ubiquitin-proteosome pathway lead to?
    • to abnormal cell growth and is associated with cancer and other diseases
    • What is the ubiquitin-proteosome pathway responsible for?
    • the rapid breakdown of proteins in hypercatabolic states, including cancer cachexia
    • What is atrophy resulting from chronic malnutrition often accompanied by?
    • more autophagic vacuoles, which are membrane-bound vesicles within the cell that contain cellular debris and hydrolytic enzymes.
    • What rises rapidly during atrophy?
    • the level of hydrolytic enzymes
    • Why are the hydrolytic enzymes isolated in autophagic vacuoles?
    • to prevent uncontrolled cellular destruction
    • Autophagic vacuoles form as needed. Why?
    • to protect uninjured organelles from the injured organelles and are eventually taken up and destroyed by lysosomes
    • Certain contents of the autophagic vacuole may resist destruction by lysosomal enzymes and persist in membrane-bound residual bodies. Give an example of this.
    • granules that contain lipofuscin, the yellow-brown age pigment.

      Lipofuscin accumulates primarily in liver cells, myocardial cells, and atrophic cells
    • Where does lipofuscin accumulate in the body?
    • (1) liver cells
      (2) myocardial cells
      (3) atrophic cells
    • What cells of the body are particularly prone to enlargement by hypertrophy?
    • (1) cells of the heart
      (2) cells of the kidney
    • What is the increase in cell size associated with? What is it not associated with?
    • an increased accumulation of protein in the cellular components (plasma membrane, endoplasmic reticulum, myofilaments, mitochondria) and NOT with an increase in cellular fluid
    • What is hypertrophy caused by?
    • specific hormone stimulation or by increased functional demand
    • List the triggers for hypertrophy.
    • two types of signals:
      (1) mechanical signals, such as stretch
      (2) trophic signals, such as growth factors, hormones, and vasoactive agents
    • Give examples of normal (physiologic) hypertrophy.
    • (1) increase in skeletal muscle size due to increased workload
      (2) increase in growth of uterus and mammary glands in response to pregnancy
    • Give a pathologic example of hypertrophy.
    • pathophysiologic hypertrophy in the heart secondary to hypertension or problem valves
    • What is hyperplasia?
    • an increase in the number of cells resulting from an increased rate of cellular division.
    • When does hyperplasia occur in response to injury?
    • when the injury has been severe and prolonged enough to have caused cell death
    • What do loss of epithelial cells and cells of the liver and kidney trigger?
    • triggers DNA synthesis and mitotic division
    • Increased cell growth is a multistep process involving production of ____________.
    • growth factors
    • What do growth factors do?
    • stimulate the remaining cells to synthesize new cell components and, ultimately, to divide
    • What often occurs along with hyperplasia?
    • hypertrophy
    • When do hyperplasia and hypertrophy occur together?
    • both take place if the cells can synthesize DNA
    • Does hypertrophy and hyperplasia occur in nondividing cells (such as myocardial fibers)?
    • in nondividing cells, only hypertrophy occurs
    • What are the 3 major types of hyperplasia?
    • (1) compensatory hyperplasia
      (2) hormonal hyperplasia
      (3) pathologic hyperplasia
    • Which of the 3 major types of hyperplasia are considered normal hyperplasia?
    • (1) compensatory hyperplasia
      (2) hormonal hyperplasia
    • What is compensatory hyperplasia?
    • an adaptive mechanism that enables certain organs to regenerate
    • Give an example of compensatory hyperplasia.
    • removal of part of the liver leads to hyperplasia of the remaining cells (hepatocytes) to compensate for the loss.

      Even with removal of 70% of the liver, regeneration is complete in about 2 weeks
    • What is hepatocyte growth factor (HGF)?
    • an important mediator in vitro of liver regeneration
    • Which cells of the body cannot regenerate?
    • (1) nerve cells
      (2) skeletal muscle
      (3) myocardial cells
      (4) lens cells of the eye
    • How are additional skeletal muscle cells made if they cannot regenerate?
    • by the fusion of myoblasts
    • In what parts of the body can significant hyperplasia occur?
    • (1) epidermal and intestinal epithelia
      (2) hepatocytes
      (3) bone marrow cells
      (4) fibroblasts

      some hyperplasia is noted in:
      (1) bone
      (2) cartilage
      (3) smooth muscle cells
    • Give an example of compensatory hyperplasia involving epidermal cells.
    • callus, or thickening, of the skin as a result of hyperplasia of epidermal cells in response to a mechanical stimulus
    • Where does hormonal hyperplasia occur?
    • chiefly in estrogen-dependent organs, such as the uterus and breast.
    • Give an example of hormonal hyperplasia.
    • after ovulation, estrogen stimulates the endometrium to grow and thicken in preparation for receiving the fertilized ovum.

      if pregnancy occurs, hormonal hyperplasia, as well as hypertrophy, enables the uterus to enlarge
    • What is pathologic hyperplasia?
    • the abnormal proliferation of normal cells, usually in response to excessive hormonal stimulation or growth factors on target cells
    • What is the most common pathologic hyperplasia?
    • the pathologic hyperplasia of the endometrium (caused by an imbalance between estrogen and progesterone secretion, with oversecretion of estrogen
    • What does pathologic endometrial hyperplasia cause?
    • excessive menstrual bleeding
    • What is pathologic endometrial hyperplasia under the influence of?
    • regular growth-inhibition controls

      if these controls fail, hyperplastic endometrial cells can undergo malignant transformation
    • What is dysplasia?
    • abnormal changes in the size, shape, and organization of mature cells
    • What is dysplasia often called?
    • atypical hyperplasia
    • Where are dysplastic changes often encountered?
    • in epithelial tissue of the cervix and respiratory tract, where they are strongly associated with common neoplastic growths and often are found adjacent to cancerous cells.
    • Why is dysplasia a worrisome change in cells?
    • because it is most often found near cancer cells and data indicate that it appears to be involved with breast cancer development
    • How is dysplasia classified?
    • mild, moderate, or severe; however, because this classification scheme is somewhat subjective, it has prompted some to recommend the use of either "low grade" or "high grade" instead.
    • Can dysplastic changes be reversible?
    • It can often be reversible if the inciting stimulus is removed
    • What is metaplasia?
    • the reversible replacement of one mature cell type by another, sometimes less differentiated, cell type.
    • How is metaplasia thought to develop?
    • from a reprogramming of stem cells that exist on most epithelia or of undifferentiated (embryonic) mesenchymal cells present in connective tissue
    • Why do these precursor cells mature along a new pathway?
    • because of signals generated by cytokines and growth factors in the cell's environment
    • Give an example of metaplasia.
    • replacement of normal columnar ciliated epithelial cells on the bronchial (airway) lining by stratified squamous epithelial cells.

      the newly formed cells do not secrete mucus or have cilia, causing loss of a vital protective mechanism

      bronchial metaplasia can be reversed if the inducing stimulus,usually cigarette smoking, is removed.

      with prolonged exposure to the inducing stimulus, however, dysplasia and cancerous transformation can occur
    • What do most disease begin with?
    • cell injury
    • When does cell injury occur?
    • when the cell is unable to maintain homeostasis--a normal or adaptive steady state--in the face of injurious stimuli
    • List some injurious stimuli of cells.
    • (1) chemical agents
      (2) lack of sufficient oxygen (hypoxia)
      (3) free radicals
      (4) infectious agents
      (5) physical and mechanical factors
      (6) immunologic reactions
      (7) genetic factors
      (8) nutritional imbalances
    • What does the extent of cellular injury depend on?
    • the type, state (including level of cell differentiation and increased susceptibility to fully differentiated cells), and adaptive processes of the cell, as well as the type, severity, and duration of the injurious stimulus
    • Do two people exposed to an identical stimulus incur the same extent of cell injury?
    • No, thay may incur varying degrees of of cellular injury
    • Why may two individuals exposed to an identical stimulus have varying degrees of cellular injury?
    • because modifying factors, such as nutritional status, can profoundly influence the extent of injury