2. Cell Adaptation, Injury, & Death Pt. 1

Define homeostasis.

Cells maintain normal structure and function in response to physiologic demands

When does cellular adaptation occur?

When cells encounter some stresses, they can undergo functional or structural changes to maintain viability/homeostasis

What is the correct way that some stimuli affect the organelles within the cell?

Can increase or decrease depending on the stimuli

What are some examples of adaptive processes?

All of these

Define cell injury.

If limits of the adaptive response are exceeded or if adaptation is not possible, a sequence of events called this occurs

Define reversible cell injury.

When the removal of stress/injury results in teh complete restoration of structural and functional integrity

Define irreversible cell injury.

If a harmful stimulus persists or is severe enough from the start

What are the morphological patterns that irreversible cell injury and death take?

Necrosis and apoptosis

Define adaptations.

Reversible changes in the size, number, phenotype, metabolic activity, or functions of cells in response to changes in their environment

Define atrophy.

Decrease in size or number of cells per unit area

Decrease in the amount of a tissue or organ after normal growth has been attained

What happens with atrophy?

An adaptive response where a tissue or organ undergoes a reduction in mass

Which list could be causes that lead to atrophy?

Decrease in work load

Loss of innervation

Loss of hormonal stimulation

Partial reduction in blood supply or hypoxia

Inadequate nutrition

Compression

Aging

Which of the following describes how atrophic cells function?

Reduced functional capacity

Still have control of their internal environment

Can produce enough energy to survive

A lot of times can return to “normal” when the stimulus is removed

What is the mechanism & biochemistry of atrophy?

Cell shrinks in volume and decreases function leading to decreased energy requirements

Which of the following correctly matches atrophic conditions?

Catabolic > Anabolic

What is represented in the organ?

Atrophy of senility

What is the most common form of starvation and cancer that is also represented in the image?

Atrophy of malnutrition/cachexia

What is one of the best ways to determine body condition score in birds?

Keel

What is serous atrophy?

When normal fat is broken down and replaced with a mucoid

What type of atrophy is shown in the image?

Disuse atrophy

Define avulsion.

Injury in which a body structure is torn off by either trauma or surgery

What kind of atrophy can be seen in the image?

Denervation atrophy

The image shows two different muscle fibers side by side. Identify each as atrophic or normal.

Left - Atrophic; Right - Normal

Define hypertrophy.

Increased size of cells per unit area

Which of the following matches skeletal/cardiac muscle hypertrophy?

Physiological response to increased workload

Which of the following represents the example of heart failure in terms of hypertrophy?

Pathological response to increased workload

Which of the following represents the etiology of hypertrophy in regards to lactation?

Physiologic response to trophic signals

Which of the following represents myocardial hypertrophy in hyperthyroid cats?

Pathological response to trophic signals

Which of the following correctly matches hypertrophy?

Anabolic > Catabolic

What is the gross appearance of the organ and microscopic appearance of the cells in regards to hypertrophy?

Larger than normal

What is represented in the image?

Left ventricular hypertrophy

Both of the images have been taken at the same magnification on a microscope. With that in mind, what is represented in the images?

Hypertrophy

Define hyperplasia.

Increased number of cells per unit area

Define metaplasia.

Replacement of a cell type by another of the same germline

In which tissues does hypertrophy and hyperplasia often present together?

Everything except cardiac and skeletal muscle