Atrophy, aplasia, and hypoplasia

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Atrophy, aplasia, and hypoplasia

Exam 1

Exam 1

Systemic lupus erythematosus (SLE): Nursing
Human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS): Nursing
Klinefelter syndrome
Disorders of sex chromosomes: Pathology review
Cell membrane
Mitosis and meiosis
Metaplasia and dysplasia
Hyperplasia and hypertrophy
Selective permeability of the cell membrane
Endocytosis and exocytosis
Glycolysis
Free radicals and cellular injury
Atrophy, aplasia, and hypoplasia
Necrosis and apoptosis
Body fluid compartments
Prader-Willi syndrome
Potassium homeostasis
Sodium homeostasis
Phosphate, calcium and magnesium homeostasis
Complete metabolic panel (CMP) - Chloride: Nursing
Acid-base map and compensatory mechanisms
Metabolic acidosis
Metabolic alkalosis
Respiratory acidosis
Respiratory alkalosis
Gene regulation
Mendelian genetics and punnett squares
Transcription of DNA
Translation of mRNA
DNA mutations
Nuclear structure
Turner syndrome
Down syndrome (Trisomy 21)
Edwards syndrome (Trisomy 18)
Patau syndrome (Trisomy 13)
Huntington disease: Nursing
T-cell development
B-cell development
Antibody classes
Introduction to the immune system
Immune response - Adaptive: Nursing
Cell-mediated immunity of natural killer and CD8 cells
Hypersensitivity reactions - Type I: Nursing
Hypersensitivity reactions - Type III: Nursing
Hypersensitivity reactions - Type IV: Nursing
Hypersensitivity reactions - Type II: Nursing
Shock - Anaphylactic: Nursing
Anaphylaxis: Nursing process (ADPIE)
Autoimmunity: Nursing
Immunodeficiency disorders - Secondary: Nursing
Immunodeficiency disorders - Primary: Nursing
HIV (AIDS)
Oncogenes and tumor suppressor genes
Biology of cancer: Nursing
Blood components
Erythropoietin
Coagulation (secondary hemostasis)
Platelet plug formation (primary hemostasis)
Anemia - Iron-deficiency: Nursing
Anemia - Aplastic: Nursing
Pernicious anemia: Year of the Zebra
Anemia of chronic disease: Year of the Zebra
Anemia - Macrocytic: Nursing
Polycythemia vera (NORD)
Polycythemia: Nursing
Thrombocytopenia: Nursing
Essential thrombocythemia (NORD)
Disseminated intravascular coagulation (DIC): Nursing
Thrombosis syndromes (hypercoagulability): Pathology review
Infectious mononucleosis: Nursing
Leukemia: Nursing process (ADPIE)
Lymphoma - Hodgkin and non-Hodgkin: Nursing
Multiple myeloma: Nursing
Hemolytic disease of the fetus and newborn: Nursing
Glucose-6-phosphate dehydrogenase (G6PD) deficiency
Sickle cell disease (NORD)
Sickle cell disease: Nursing process (ADPIE)
Thalassemia: Nursing
Hemophilia: Nursing process (ADPIE)
Hemophilia: Year of the Zebra
Immunoglobulins: Nursing pharmacology

Assessments

USMLE® Step 1 questions

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High Yield Notes

9 pages

Questions

USMLE® Step 1 style questions USMLE

0 of 1 complete

A 54-year-old man comes to the clinic due to pain and paresthesia in his right hand. He currently works as a mechanic. Examination shows decreased muscle bulk of the right thenar eminence. A nerve conduction study confirms diagnosis of carpal tunnel syndrome. Which of the following helps explain the appearance of the thenar eminence?

External References

First Aid

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2023

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Aplasia p. 631

of thymus p. 638

Cutis aplasia

Patau syndrome p. 61

Fungal infections

thymic aplasia p. 114

Hypocalcemia p. 335, 609

thymic aplasia p. 114

Parathyroid hormone (PTH) p. 334

thymic aplasia p. 114

Tetany

thymic aplasia p. 114

Tetralogy of Fallot p. 302

thymic aplasia p. 114

Thymic aplasia p. 114, 638

Truncus arteriosus

thymic aplasia p. 114

Transcript

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Content Reviewers

Growing is an important part of living.

In fact, everything from an individual muscle cell, to a baby blue whale - strives to grow, in order to live and perhaps replicate or reproduce.

Sometimes, however, growth fails to occur, or even reverts back, and we call that atrophy, aplasia, or hypoplasia, depending on the situation.

Let’s break down these words. Atrophy, “a” means “no”, and “trophy”, means nourishment. So, atrophy means “no nourishment”.

Aplasia, “a” means “no” and “plasia” means development. So aplasia means “no development”, and “hypo” means “under” so hypoplasia is “under formation”.

In a nutshell, atrophy is the reduction in size of a cell, organ, or tissue, after it has attained its normal, matured growth.

This happens either through decrease in cell number or decrease in cell size.

Decrease in cell number most commonly happens due to apoptosis, which is controlled type of cell death - a bit like cellular suicide.

An example would be weight loss. In the first few weeks to months of eating healthy and losing weight, the fat cells or adipocytes get smaller but are ready to fill up again with fat.

Over months to years of eating healthy, however, the adipocytes undergo apoptosis - and at that point it’s a bit more difficult to gain back the weight.

Decrease in cell size, however, is a bit more complex.

Usually, the first step is the loss of nerve or hormonal supply, both of which provide nourishment to cells.

Then there’s something called the ubiquitin proteasome pathway.

You see, cells have a cytoskeleton, which is a framework of various filaments that keep the cell propped up.

As cells start getting less nourishment, those filaments get “tagged” for demolition with a protein called ubiquitin.

Ubiquitin proteins start to attach to one another - a process known as polyubiquitination.

And then an intracellular protein complex called a proteasome comes in to destroy all polyubiquitinated filaments, causing the cell to decrease in size.

Some organelles can also be tagged with ubiquitin; and when that happens, a bubble of phospholipid bilayer membrane forms around the organelle, creating a vacuole.

Next, lysosomal vesicles which are filled with degradative enzymes, fuse with the vacuole; destroying the unfortunate organelle. Like being sent off to the firing squad.

An example is muscle atrophy.

Anytime there’s long-standing disuse of muscles, like extended bedrest, zero gravity, or during long study sessions, there can be a loss of muscle mass and strength.

Summary

Atrophy, aplasia, and hypoplasia all refer to degeneration or poor growth of cells and tissues. Atrophy refers to the reduction in size of a tissue, or organ, after it had been normally formed and attained its normal growth. With aplasia there is a complete congenital lack of the cells, tissue or organ, whereas in hypoplasia, precursor cells are present, but they do not develop into their intended organs during embryogenesis. All three conditions can be caused by a variety of factors, including disease, injury, or genetic abnormalities

Sources

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