Lecture 19 Flashcards Preview

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Flashcards in Lecture 19 Deck (18)
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1
Q

What factors affect cells and tissues ability to adapt?

A
  1. State of differentiation (3 types - labile, stable or permanent) 2. Particular vulnerability to certain agents 3. Blood supply 4. Nutrition 5. Previous state of the cell
2
Q

What are adaptive changes:

A

Reversible changes in mature cells and tissues after growth has occurred.

3
Q

Define the term atrophy:

A

A reduction in the size or amount of the organ, tissue or cell. This is due to a decrease in the size and/or number of specialized cells or organelles. This can be physiological or pathological

4
Q

Describe the mechanism behind atrophy occurring:

A

Increase in apoptosis is responsible for decrease in number of cells. The remaining cells survive at a small size - fewer mitochondria, myofilaments and ER. The reduction in cell size is associated with catabolism > anabolism

5
Q

What are the causes of atrophy (provide one pathological and one physiological)?

A

Pathological: inadequate nutrition and decreased blood supply Physiological: decreased workload (disuse)

6
Q

What process has occured in this histological slide and how can you tell?

A

Muscle atrophy - nuclei look more concentrates and each nuclei will also look a little bit more plump

7
Q

Define the term hypertrophy:

A

Increase in the size of an organ or tissue due to an increase in the size of its specialised cells

8
Q

What types of cells will hypertrophy typically occur in?

A

Cells with an increased workload that cannot divide e.g. muscle

9
Q

What is the appearance of hypertrophic cells on a histological slide?

A

General increase in the number of organelles which increases the size of the cell (limited by SA: vol ratio)

10
Q

Provide an example of compensatory and hormonal hypertrophy:

A

Compensatory: removal of a kidney, increased workload - striated and cardiac muscle

Hormonal: pregnancy causing uterine hypertrophy

11
Q

What are the mechanisms of hypertrophy?

A

Trophic triggers: growth factors, hormones, cytokines. May be produced endogenously or exogenously causing increased gene expression

OR

physical triggers - e.g. pressure stretching on the cell membrane

12
Q

Name the two processes occuring in the image below:

A
  1. Left ventricular concentric hypertrophy
  2. Left ventricular dilation/eccentric hypertrophy
13
Q

What is meant by the term hyperplasia?

A

An increase in the size of an organ or tissue due to an increase in the number of specialised cells. May be due to physiological or pathological causes.

14
Q

Provide an example of physiological hyperplasia and an example of pathological hyperplasia:

A

Physiological hyperplasia: haematopoetic system after blood loss, mesentric lymph nodes

Compensatory/reactive: cyclical changes in mammary gland or endometrium

Pathological hyperplasia: hormonal excess - XS erythropoietin, XS estrogen, reparatory - to restore architecture or function, infectious organisms

15
Q

Define the term metaplasia:

A

change from one type of specialised fully differentiated adult cell to another adult cell type (often less specialised)

16
Q

Why does metaplasia normally occur?

A

generally metaplasia is a protective response - often a response to a chronic irritant

17
Q

How does metaplasia generally occur?

A

reprogramming of stem cell by cytokines, growth factors (TGF-B), ECM components

18
Q

Define the term dysplasia:

A

It is disordered growth that generally occurs in the epithelium. It often occurs in metaplastic/hyperplastic epithelium. This results in a loss in uniformity of individual cells plus losses in architectural organisation. It may progress to neoplasia.