Cells and Repair Flashcards
What do all cells arise from?
A zygote
What 3 types of tissues does the zygote differenciate to?
- Ectoderm
- Endoderm
- Mesoderm
What does the ectoderm differentiate into?
- Hair
- Nails
- Epidermis
- Brain
- Nerves
What does the endoderm differentiate into?
- Mucosa (internal lining) of the intestinal and respiratory tracts
- Liver
- Pancreas
What does the mesoderm differentiate into?
- Dermis (Deep layer of the skin)
- Bone
- Skeletal Muscle
- Blood vessels
- Smooth Muscle
- Pleura
- Peritonium
- Pericardium
- Kidneys
- Gonads
The most potent stem cells have the broadest/narrowest powers?
Broadest (they can give rise to an entire organism or any particular cell in the body)
This stem cell can give rise to an entire organism or any particular cell in the body
Totipotent Stem cells
ex. Zygote (and the first 8 cells that arise from the zygote)
This stem cell can produce any type of tissue (ex. heart, brain, liver, skin) but cannot form an entire new human being
Pluripotent Stem Cell
AKA Embryonic stem cells
This type of stem cell can produce more specialized cells and a limited range of cells
Multipotent Stem Cells
ex. Mesenchymal Stem cells, hematopoietic stem cells
What kind of division do stem cells have?
Asymmetric division
What does asymmetric division mean?
The stem cells are not alike…
- Becomes a new stem cell
- Becomes a more specialized cell
T/F: Stem cells persist into adulthood?
True
This type of tissue has many cells in the cell cycle at any given moment.
- The cells of this tissue divide frequently
- Need ongoing replenishment b/c they are constantly damaged or exposed
Liable tissues
ex. epithelial skin, urinary tract, GI tract
This type of tissue only has a few cells in the cell cycle at any given moment
- cells don’t divide very frequently
- they can increase cell production when needed (injury)
Stable tissues
ex. liver, pancreas, smooth muscle cell
This type of tissue have very few or no cells in the cell cycle
-have few/no stem cells
Permanent Stem Cells
ex. brain, skeletal muscle, cardiac
What are some ways that cells can be injured…?
Anoxia Hypoxia Ischemia Physical Chemical Toxins Microbes Inflammation Nutrition Genetic/Metabolic Aging
Severe injury leads to what?
Cell death- necrosis
What are the 3 phases of Interphase?
G1, S, G2
What does stimulating proto-oncogenes do?
Allows for mitotic condition
What geneso Suppresses mitosis
o Allows for correction in damaged DNA
o Stimulates by damage then suppresses growth to stay in the G1/S phase
Tumor suppressor genes
List some ways that cells can be injured?
- Anoxia
- Hypoxia
- Ischemia
- Physical/Chemical/Radiation
Define atrophy
- The cell shuts down its metabolic processes to conserve energy
- 2 types of atrophy
- Decreased size and function
What are the 2 types of atrophy
- Physiologic Atrophy- normal part of life- shrinking of the thymus gland
- Pathologic Atrophy- lack of disuse or lack of physiologic support
Characteristics/Causes of atrophy
Decreased functional demand Not enough oxygen Insufficent nutrients Aging Inter. of trophic cells Chronic cell injury Increased pressure
Define hypertrophy
Increased cellular size and function/workload
Increase in work load, neuroendocrine stimulators
Often seen in muscles because they have few stem cells (Permanent Tissue) which means it can’t grow new cells so it needs to enlarge current cells
Define hyperplasia
Enlargement of an organ/tissue caused by the increase of the reproduction rate of its cells
Ex. Due to hormonal stimulation or chronic injury or increased functional demand
Define metaphasia
The irreversible change of one cell type into another caused by chronic injury
Common in epithelial cells- because they are short lived and being replenished
One cell type differentiated into a new cell type
Define dysplasia
The enlargement of an organ/tissue by the proliferation of abnormal cells
Disordered growth
Variation in size and shape of the cells, nuclear enlargements, hyperchromatism (darkened DNA- darker colors) chaotic look
Persistent Injury: increases or decreases risk for dysplasia
Increases
Characteristics of Apoptosis
Natural, NORMAL, programed cell death
Physiologic normal response
Does not stimulate inflammatory response
Usually in single cells
Characteristics of Necrosis
Pathologic death of cells because of injury Stimulates inflammatory response Not normal Due to some sort of injury Usually in blocks of cells
Types of Necrosis
- Coagulative Necrosis
- Liquefactive Necrosis
- Causeous Necrosis
- Fat Necrosis
Define Coagulative Necrosis
gel like change in blocks of freshly dead cells
The artitecture is still intact but the cells are dead
Ischemia is the most common cause
Most common type of necrosis
Hallmark: Preserved structure
Irreversable
Ex. Heart muscle- still have the heart structure but there are no active cells
Define Liquefactive Necrosis
cell death in which the dead tissue dissolves into fluid
Abscesses
Dead tissue and cells that dissolve within
Cavity that has been dissolved in the fluid
Define Causeous Necrosis
variant form of coagulative necrosis with limited liquefaction and obliterated cellular tissue\
Cheese like appearance
Tuberculosis
Define Fat Necrosis
specialized form of necrosis that only occurs in fat
Pancreatitis
Necrosis in dead fat tissue
Exposes free fatty acids that combine with calcium that forms a soap like appearance
Severe trauma
What are the Intracellular Accumulations for Chronic Stress/Injury
- Fat
- Water
- Cholesterol
- Protein
- Pigments
- Environmental Particles
Examples of cholesterol accumulation
o In the cells of arteries
o Atherosclerosis
Examples of protein accumulation
o Misfolded/Abnormal Proteins in disease
o Lead to degradation
o Alzheimer’s disease
Examples of Pigment accumulation
o Demonstrates “wear and tear”
o Lipofuscin
Examples of Environmental particle accumulation
o Inhaled particles that collect in lungs
o Carbon molecules impair the cell functions of the lungs
o Cigarette smoke
Examples of fat accumulation
o Lots in the liver o “Fatty Liver” o Cause is alcohol o Steatosis o Chronic or acute injury o Alcohol increases fatty acid synthesis so myocardial oxidation increases, increasing triglyceride production, so liver can’t let out triglycerides o REVERSIBLE if you remove the reagent o Can happen after one time o If sustained it can lead to chronic illness o Even obesity can lead to fatty liver
Examples of water accumulation
o Hydropic swelling
o Reversible once the cause is removed
o Disruption in the sodium pump cells
Sodium is high outside the cell, K is high inside the cell
What are some examples of lysosomal storage disorders
• Hurler disease • Phenylketonuria (PKU) • Wilson Disease • Hepatic Encephalopathy Tay-Sachs disease
What are the types of inflammation?
- Acute
- Chronic
Acute characteristics
- Short lived
- Lasts a few days
- Brief Injury results in acute inflammation
Chronic characteristics
- Mild, longer termed injury that lasts a few years
- Persistent Injury results in chronic inflammation
Why inflammation?
- Normal response of the body
- The goal of inflammation is to return to a normal functioning tissue
- Limits extent of injury
- Neutralize the offending force
- Eliminate the cause of injury
- Initiate the repair process
What cells are used in acute inflammation
Neutrophils
• main inflammatory cells in acute inflammation
Platelets
Mast Cells
What cells are used in chronic inflammation
Macrophages
• Phagocytes
Lymphocytes
• Main inflammatory cells of chronic inflammation
Plasma Cells
• B cells that are actively making antibodies
What are the major cells in acute inflammation
Neutrophils
What are the major cells in chronic inflammation
Lymphocytes
What are the 3 types of signalling
- Paracrine- molecules released by cells that act on nearby cells
- Autocrine- signals that act back on the generating cell
- Endocrine- signals that travel through the blood stream
What are the steps of acute inflammation?
- Injury Occurs
- Immediate vasoconstriction followed by vasodilation
a. More blood volume- slower speed though because the vessel is so enlarged - Capillaries become permeable (causing edema)
- Neutrophils migrate and accumulate
- Monocytes and Macrophages
- Exudate Accumulates (inflammatory fluid)
- Plasma begins to clot
S&S of acute inflammation
Redness
Edema
Pain
Heat
Define acute inflammatory exudate
accumulation of fluid and white blood cells at the injured site
- Accumulates in several anatomical patterns…
What are the 3 types of Acute Inflammatory Exudate
- Serous
- Fibrinous
- Suppurative
- Mild, short term inflammation
- Water filled, low proteins, inflammatory cells (Blisters from sunburn)
Serous Inflammatory Exudate
- Follows severe injury
- High protein and fibrin content
- Thicker and wetter
- More neutrophils
- Scab is an example
Fibrinous Inflammatory Exudate
- Severe acute injury
- Seen in liquefactive necrosis
- Lots of pus
- Lots of necrotic debris and neutrophils
Suppurative Inflammation
What are the consequences of acute inflammation?
- Complete resolution- changes due to the degree of injury
- Scarring- occurs with severe or repeated acute inflammation
- Abscess
- Chronic Inflammation- if irritant isn’t removed
Characteristics of chronic inflammation
- Lasts weeks to years
- Lots of lymphocytes and macrophages
What are the 3 causes of chronic inflammation?
- Persistent Infection
- Autoimmune disease
- Persistent Injury
- Central area of necrosis with lots of macrophages in a certain area
- Cause inflammatory nodules that are called granulomas
- Adjacent macrophages aggregate to form huge cells with abundant cytoplasm with many macrophage nuclei
- Result of chronic inflammation
Granulomatous Inflammation
Inflammation beyond the site of injury
- Systemic
- Involvement of the lymphatic system
- Production of reactant proteins
What are the 3 steps in the repair process
- Cell migration
- Angiogenesis
- Scar development
What happens during cell migration
o Leukocytes go to the wound to minimize damage and clear debris
o Leukocytes produce cytokines that stimulate migration and proliferation of myofibroblast
Myofibroblasts produce collagen to knit back the pieces and provide other raw materials
o Angioblasts sprout
What happens during ANGIOGENESIS
o The growth of new blood vessels into the wound
o New blood vessels to carry oxygen and nutrients to the site that needs it
o Under the influence of vascular endothelial growth factor
o Essentialllll!!
What happens during scar development
o Form granuloma tissue- highly vascularized (when you pick off a scab and it is very sensitive to breathing)
o Fresh and fragile- bleeds easily
o Forms by fibroblasts and new capillaries
o Collagen accumulates
o Scar development
Define first intention
- Small, narrow wound
- Like a paper cut or surgical incision
Define second intention
- Longer to heal- same process as first intention- it just takes longer
o More dead tissue to be removed
o Regeneration is slower because the wound is wider - More fiber to thicken
- Like deep skin burns or intestinal ulcers
What are factors that influence healing?
-Poor Nutrition
-Steriod Drugs
-Foreign objects
-Mechanical Forces
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