Chapter 2-Cellular Responses to Stress, Injury and Aging Flashcards
Discuss adaptive tissue cell response.
change size and form
do not change their function
What is Atrophy?
DECREASE in the size of a tissue organ resulting from a DECREASE in the size of the individual cells or number of cells
What is atrophy caused by?
disuse denervation loss of endocrine stimulation ischemia inadequate nutrition (i.e. diabetes)
What is Ischemia?
no blood flow
meaning lack of oxygen
What is denervation?
no stimuli going to the cells
no signals being received
Discuss Hypertrophy.
- larger cell size and functioning tissue mass
- a result of increased workload
- most common in cardiac and skeletal muscle tissue.
- think body builders: they changed the size and shape but they did not change the function
- Can also occur in your cardiac muscle and other organs that have been damaged or in the case of kidney removal, one is gone but the other will grow larger to make up the work.
Discuss Adaptive or compensatory Hypertrophy
increase in cell size and an increase in the amount of functioning tissue mass
Adaptive = body builders Compensatory = compensating for a lack of (hypertrophic cardiomyopathy = bad)
Discuss hyperplasia.
-Increased number of cells in organ/tissue caused by a stimuli of some sort
Causes:
compensatory
hormonal
pathological
Where does hyperplasia occur?
Occurs in cells that have mitotic division:
- epidermis
- intestinal epithelium
- glandular tissue
Compensatory hyperplasia
part of the liver is removed so the cells hyperplasia to make up for the part of the liver that has been removed
Discuss Metaplasia
- an adult cell type is replaced by another adult cell type
- occurs in response to chronic irritation/inflammation
- not usually good
*Barret’s Esophogial: the cells in the esophagus are damaged because of the constant stomach acid; the cells are replaced and are more receptive to cancer
Discuss dysplasia
- deranged cell growth
- cells will vary in shape, size, and organization
- lead to cancers
- smokers are at high risk
- cervical
- not necessarily reversible
*inability to function like the cells they were originally designed to function as
What is the reason for the difference in cell shape, size and number?
Adapting to the constant changes a body goes through regularly
ADAPTATION
What will happen if cells do not adapt?
The cells will die if they do not adapt to the changes.
NECROSIS
Discuss Intracellular accumulations
-represents the buildup of substances that cells cannot immediately use or dispose of
- things get stuck in the cells
- sometimes these buildups help in the manifestations of Signs and Symptoms of a particular issue.
What are some examples of intracellular accumulations?
- unused food, such as lipids and glycogen
- abnormal proteins
- pigments
- calcium salts
*Jaundice = excess bilirubin built up in the body
What are pathologic calcifications?
-abnormal tissue deposits of calcium salts and minerals
What are dystrophic calcifications?
- in injured cells
- Artherosclerosis: aorta, large vessels, heart valves
- can cause failure of the organ
Atherosclerosis
Dystrophic calcifications in the aorta, large vessels, heart valves
What are metastatic calcifications?
- in normal tissues, from elevations in blood calcium levels
- hyperparathyroidism
(parathyroid: 4 small rice sized nodules = only function is to maintain calcium levels - increased parathyroid function meaning that there is too much calcium being allowed to accumulate)
What are some causes of cell injury?
- mechanical (blunt force/hitting into something)
- temperature (frost bite/burns)
- electrical
- radiation (sunburn)
- chemicals (drugs/internal or environmental)
- biological agents (bacteria/virus = replicating and producing more injury to the cells)
- nutritional imbalances (too much in and/or not enough in
Causes of cell injury
hypoxic cell injury
ischemic cell injury
Hypoxic cell injury
- cell deprived of Oxygen
- Extent of injury depends on needs of the cell and degree of cellular hypoxic
- can occur from inadequate amounts of oxygen or from inability of cells to use oxygen
*sometimes the cells are messed up and don’t know how to use the oxygen and therefore still stay sick (septic cases)
Example of hypoxic cell injury
drowning victim
Ischemic cell injury
- insufficient blood flow to the cells
- when this occurs there is an increased accumulation of intracellular calcium
- comes from the release of stored calcium from the mitochondria
Discuss Ischemic stroke
- blood flow isn’t getting to the brain
- Need to profuse the brain for it to function
- some kind of clot is stuck somewhere in a vessel and blood is just not getting to the brain
Mechanisms of Cell Injury
- Depletion of ATP
- Free Radical Formation
Depletion of ATP
(Mechanism of Cell Injury)
-Depletion and decreased ATP synthesis are associated with hypoxia and chemical cell injury
-ATP is a coenzyme that helps carry energy to the cells
Free Radical Formation
(Mechanism of Cell Injury)
-Uncontrolled free radical production causes damage to cell membranes, cross-linking of cell proteins, inactivation of enzyme systems or damage to nucleic acids
-Free Radicals are unpaired electrons - cause damage by destroying the phospholipids in the membranes
Discuss Apoptosis
preprogrammed cellular death
-a highly selective process that eliminates injured and aged cells
-cells are removed and replaced with vital cells
-removes cells that are being replaced or have
worn out”
-removes unwanted tissue
*every cell has a life span
*a healthy, normal process
**sometimes when people get very sick/septic all cells apoptosis at the same time (leukemia - blood cells not forming well in the bone marrow)
Discuss NECROSIS
Unregulated death caused by injuries to cells
- cells swell and rupture
- inflammation results
- cell death in an organ or tissue that is still part of a living person
- premature cell death, abnormal, interferes with the normal cycle of cell life
**alcohol and acetopmenophen = damage the liver
What can Necrosis lead to?
Gas Gangrene
-will spread and cause more cell damage or death
Discuss Gangrene
- life threatening infection
- gas can travel through the body and causes tissue necrosis leading the systemic death
- can come from an impaired arterial blood flow to the tissue (meaning that there is a lack of oxygen)
- frost bite
- diabetes
- poor circulation
- *Arterial flow is impeded and oxygen is not getting to the cells.
Discuss Injured cells
- They are dysfunctional
- have impaired flow of substance through their cell membranes as a result of altered permeability
- These cells become swollen as a result of altered cell volume regulation
- They can ultimately rupture and die
Discuss Aging
Most theorists believe that cellular aging is related to programmed changes in combination with genetic influences.
Necrotic tissue may be reversed using high concentrations of oxygen?
FALSE = necrotic means death - dead, no return.
