Cellular injury

Question 1

How does cellular injury occur

Answer 1

its the result of cells being exposed to conditions where they no longer are able to adapt

Question 2

Conditions which can cause cellular injury

Answer 2

*physical trauma - causes the cell content to leak out
*exposure to high temp - denatures enzymes and membrane proteins
*exposure from pathogens - toxins can damange the cell membrane
*damage from immune response - WBC damage the cell membrane

Question 3

When can cellular injury be reversable

Answer 3

if the cell is able to repair itself as the injury is not too extensive and can be removed so the cell can adapt and restore homeostasis

Question 4

When is cellular injury irreversibale

Answer 4

if the injury is too much, or for too long and the cell is unable to repair itself

Question 5

The 2 main causes of cellular injury

Answer 5

1. Damange to the cell membrane so the contents leak out
2. Descrease in oxygen supply so anaerobic respiration occurs and produces lactic acid (denatures proteins), and not enough ATP to sustain cell processes

Question 6

How does cellular swelling occur?

Answer 6

*Reduced oxygen supply to cells/tissues
*Cells begin anaerobic respiration *Lactic acid accumulated reducing pH in cells/tissue
*Less ATP produced Proteins/enzymes denature
*Sodium potassium pump unable to actively transport Na+ and K+ across cell membranes
*Na+ accumulate in cells
*More water enters cells by osmosis causing them to swell

Question 7

How does damage to the Na+/K+ pump cause cellular swelling?

Answer 7

*There is an imbalance in ion concentration
*Sodium (ions) not removed
*Too many potassium ions pumped in
*Increased ion concentration inside cell
*Water moves into the cell through osmosis
*Increased water causes cell to swell

Question 8

What is hyperplasia

Answer 8

Cells divide more frequently than usual (increased rate of mitosis) Increase in cell numbers

Question 9

What is Hypertrophy?

Answer 9

Cells increase in cell size and volume, and if enough cells in an organ hypertrophy the whole organ will increase in size.

Question 10

What is Atrophy

Answer 10

Cells decrease in size or number, causing cell death. If enough cells in an organ undergo atrophy the entire organ will decrease in size

Question 11

What is metaplasia

Answer 11

Change from one differentiated cell type to a different differenciated cell type

Question 12

What is the first response to tissue injury

Answer 12

Inflammation

Question 13

What is a heamatoma

Answer 13

A bruise, caused by damage to capillaries resulting in a localised bleed intotissues

Question 14

What are the different types of bruising

Answer 14

Petechiae - small dots
Purpura - large flat patches

Question 15

What is a heamorrhage

Answer 15

Uncontrolled bleeding as a result of an injury where a blood clot is unable to from

Question 16

How do blood clots/scabs form

Answer 16

*Activated thrombocytes (platelets) release thromboplastin *thromboplastin converts prothrombin into thrombin which causes platelets to aggregate/stick to each other.
*This forms a plug of platelets and red blood cells
*thrombin converts (soluble) fibrinogen to (insoluble) fibrin
*fibrin strands form a mesh and red blood cells /platelets are caught up in the mesh

Question 17

What do blood clots contain

Answer 17

Red blood cells, platlets, fibirn

Question 18

What vitamin is needed to help blood clot

Answer 18

Vitamin K which comes from leafy green vegetables

Question 19

What is ischemia

Answer 19

Blood flow isf th reduced to a part of the body

Question 20

2 types of ischemia

Answer 20

Hypoxia - reduced oxygen to tissues and cells
Anoxia - absence of oxygen in tisses and cells

Question 21

How does an Ischemic stroke cause brain damage

Answer 21

a blood clot in a blood vessel in the brain prevents blood flow which redcues the amount of oxygen reaching the brain cells causing hypoxia so the bain cells cant carry out aerobic respiration leading to necrosis

Question 22

How does ischemia of the cardiac muscle lead to a heart attack

Answer 22

A blood clot forms in the cornory artery which prevents blood flow to the cardiac muscle so it becomes ischemic, this means that there is a lack of oxygen for aerobic respiration so there is no/less ATP for contraction of the heart muscle

Question 23

What is necrosis

Answer 23

Cell death following severe cell damage

Question 24

How does necrosis occur

Answer 24

there is an unregulated digestion of cellular components due to the release of hydrolytic enzymes from lysosomes. This causes the cell membrane to break down and become leaky releasing the products of cell death into tissue fluid

Question 25

How do pressure sores occur

Answer 25

Pressure sores develop in people who stay in the same laying/sitting position all day, the pressure applied to soft tisses where the body is compressed causes ischemia which causes soft tissue damage including atrophy and necrosis