1
Q
Homeostasis
A
- The maintenance of steady state by the bodys internal control system
- The goal of treatment
2
Q
Cellular homeostasis
A
- Referes to the maintenance of a constant internal state in a changing environment
- A state of balance
-Each cell in a multicellular organism needs to maintain homeostasis
3
Q
What does the cell need to survive
A
- Obtain and use energy
- Make new cells
- Exchange materials
- Eliminate waste
4
Q
How is cellular homeostasis achieved
A
- Through diffusion, osmosis (passive transport)
- Active transport which requires energy
5
Q
Diffusion
A
- The process of movement along a concentration gradient from high concentration to low concentration
6
Q
Two ways diffusion can happen
A
- Across the phospholipid bilayer (simple diffusion)
- Through the protein channels (facilitated diffusion)
7
Q
How does diffusion maintain cellular homeostasis
A
- Cellular food (glucose, oxygen…) can diffusing into the cell
- Waste products can diffuse out of the cell
8
Q
Osmosis
A
- The diffusion of water to balance out the concentration of other molecules
- The water follows the concentration gradient
9
Q
How does osmosis maintain cellular homeostasis
A
- It maintains a specific water balance which is needed for chemical reactions
-Balances out the concentration of other molecules
10
Q
Active transport
A
- Needs atp
-Used when things need to move against concentration gradient
11
Q
How does active transport maintain cellular homeostasis
A
- To get needed materials into the cell that have a higher concentration within
12
Q
Are all the purposes of cells responding to change beneficial
A
No some can be detrimental
13
Q
Ways cells respond to change (5)
A
- Atrophy
- Hypertrophy / hyperplasia
- Metaplasia
- Dysplasia
-Increased enzyme synthesis
14
Q
Atrophy
A
- A reduction in size of the cells
- Response to diminished function, inadequate hormonal or neuronal stimulation, reduced blood supply
- Example is how a muscle gets smaller after wearing a cast
15
Q
Hypertrophy
A
- An increase in sie of each cell without an increase in number of cells
- Example is muscles getting bigger in weight lifters
16
Q
Hyperplasia
A
- An increase in the size of a tissue or organ caused by an increase in the number of cells
- Example benign prostatic hyperplasia (BPH)
17
Q
BPH
A
- Benign prostatic hyperplasia
- The prostate increases in size and leads to difficulty in urination
18
Q
What is more likely to result in an increase in the number of drug receptors
A
- Hyperplasic tissue (adds more cells
19
Q
Metaplasia
A
- A change from one type of cell to another that can tolerate a new environmental condition
-Example: the ciliated columnar lining of the trachea turns into squamous epithelium to provide more protection in cig smokers (often the place where cancer can begin but not the cause of cancer
20
Q
Dysplasia
A
- The development and maturation of cellds that are disturbed and abnormal
- Associated with chronic irritation or inflammation
-Can progress to neoplasia
21
Q
Neoplasia
A
- Formation of a tumour
22
Q
Increased enzyme synthesis
A
- A response to increased demand to cell to synthesize more enzyme from the smooth endoplasmic reticulum
- Has an impact on other substances that enzyme also metabolizes
- Example: alcoholics produce more enzymes to metabolize it so it can eliminate it faster
23
Q
Cell injury
A
- Can be reversed if the cause is removed and normal cell function restored
- If the injury exceeds the ability of the cell to recover–> death
24
Q
Cell swelling
A
- Occurs when the transport mechanism fails (can be from no atp present) (sodium and water follows) into the cell which causes it to swell
- Can be revered if energy production recommences
25
Hydropic swelling
If the swelling continues fluid filled vacuoles accumulate
26
Does water or sodium go into the cell first
sodium, water follows
27
Steatosis
- Cell injury through fatty change
- Normal function through enzyme systems; fat is metabolized and exported
- Occurs when the enzyme systems are impaired leading to accumulation of fat droplets within the cytoplasm
-Commonly occurs in liver
28
Why is cell swelling and fatty change bad
- First sign of cellular injury
- Changes the structure of the cell
-Swelling of multiple cells in an organ increase pallor (lighter colour), turgor (normal tension in living cells), and weight
29
Necrosis
- Cell death
-Cell death will occur when the injury is not reversible
30
Infarction
Lack of blood supply
31
What happens when cells die
- Mitochondria changes shape and developed calcium deposits
- Lysosomal enzymes are released and digest the cell
- Cell membrane ruptures
- Nucleus shrinks and breaks into fragments or dissolves
- May result in calcium deposition in tissue (can be used to detect necrosis)
32
Apoptosis
- Programmed cellular self destruction
- Normal, if doesn’t happen when it should can cause disease
-Doesn’t need to be injured to die, uterine tissue during menstruation is lost
33
How is apoptosis begun and does it provoke a host response
- It can be started by an immune response, hormone response, number of cell divisions..
-It does not provoke a host response (immune response or inflammation)
34
Cell aging
- All cells age and then die
- Normal cells undergo the hayflick limit
- Once limit reached cell undergoes apoptosis
- Stem cells are immune to the hayflick limit
-Some cancer cells activate repairing mechanism and can divide indefinitely
35
Hayflick limit
The fixed number of divisions that normal cells undergo before they die
36
Do all cells age the same
- No different organ systems are more susceptible
- Neurons are incapable of division
- Organs with constantly dividing cells are more prone to cancer
- Enzyme systems become less active and the cells are less resilient to chemical influences like reactive oxygen species or environmental agents
121
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