Cell Birth and Death
A fundamental behaviour in normal physiology
- Growth
- Renewal
- Repair
- Shaping
- Removal of aged cells with DNA damage
Processes linked to cell birth and death
Birth example: Embryogenesis
It would be impossible to grow a body without cell birth
Birth example: Tissue Regeneration
Skin epithelial cells proliferate in response to injury
Processes linking to cell birth and death
Example: Embryogenesis, shaping the body
Another example includes brain maturation- At birth an infants brain is packed with around 100
billion neurons- some 15% more than it will have as an adult
Cell Birth and Death linked to PATHOLOGY
Birth:
- Cancer:
- Cancer/tumorigenesis
- (Benign or malignant)
- Death:
- Degenerative diseases (Alzheimer’s disease, myopathy)
- Acute injury/ trauma
Medical Conditions linked to cell birth and death
Birth (Pathology): Gigantism
For example, Robert Waldow is the tallest verified human
Medical Conditions linked to cell birth and death
- Death (Pathology): Neurodegenerative disease ( Huntingtons)
- Destruction of nerve cells due to presence of a mutated protein, critical for maintainance
of nerve cells
Birth: the cell cycle
All cells are produced via the process of division
In eukaryotes this involves the cell cycle: Observable phrases with distinct structures and
behaviours
, Birth: Cell Cycle and Control
- Cell cycle results in growth and division to generate two cells
- A cell with 46 chromosomes undergoes mitosis to generate two cells
A dividing cell undergoes four phases of the cell cycle: G, S, G2 and M
The M phase is known as mitosis and has 5 sub stages
Phases of the cell cycle
1) As soon as a cell is born it can exit the cell cycle and start to differentiate/ mature/
specialise
2) Enter the G0 stage (quiescence)
Inactivity or dormancy (still alive)
Stem cells sometimes remain in G0
Phases: As soon as a cell is born, it can
1) Move into the G1 phase known as the gap phase. Cells can synthesise proteins, grow
and perform functions
2) S stage- ( known as the synthesis phase). Copies are made of genomic DNA and
centrioles . Nuclear content doubles (replication)
3) Gap phase 2 - Checks accuracy of DNA replication and repairs damage. Synthesises
enzymes needed for M phase
4) Mitosis- The five sub stages of cell division are performed. Each one of the two DNA
copies is packed into the new nuclei and cell membrane divides
How do we observe cell division?
- Histological (immunohistochemistry- IHC) markers are a staple of pathology and cell
biology
Different markers for different phases: Proliferation
Marking G1, S, G2, M
Ki67 IHC marker
KI67 is a nuclear protein, hence brown areas represent the cell nucleus
G0 cells are unmarked
Grades and the Ki-67 index
The grade of a large bowel or rectal neuroendocrine tumour (NET) tells you how much the cells
look like normal cells under a microscope . It gives you and idea of how the tumour might
behave when it spreads
There are different ways to grade NETs in the Uk use a system created by the World Health
Organization (WHO) which is divided into 3 different groups
- Grade 1 (NET G1 or WHO 1)
A fundamental behaviour in normal physiology
- Growth
- Renewal
- Repair
- Shaping
- Removal of aged cells with DNA damage
Processes linked to cell birth and death
Birth example: Embryogenesis
It would be impossible to grow a body without cell birth
Birth example: Tissue Regeneration
Skin epithelial cells proliferate in response to injury
Processes linking to cell birth and death
Example: Embryogenesis, shaping the body
Another example includes brain maturation- At birth an infants brain is packed with around 100
billion neurons- some 15% more than it will have as an adult
Cell Birth and Death linked to PATHOLOGY
Birth:
- Cancer:
- Cancer/tumorigenesis
- (Benign or malignant)
- Death:
- Degenerative diseases (Alzheimer’s disease, myopathy)
- Acute injury/ trauma
Medical Conditions linked to cell birth and death
Birth (Pathology): Gigantism
For example, Robert Waldow is the tallest verified human
Medical Conditions linked to cell birth and death
- Death (Pathology): Neurodegenerative disease ( Huntingtons)
- Destruction of nerve cells due to presence of a mutated protein, critical for maintainance
of nerve cells
Birth: the cell cycle
All cells are produced via the process of division
In eukaryotes this involves the cell cycle: Observable phrases with distinct structures and
behaviours
, Birth: Cell Cycle and Control
- Cell cycle results in growth and division to generate two cells
- A cell with 46 chromosomes undergoes mitosis to generate two cells
A dividing cell undergoes four phases of the cell cycle: G, S, G2 and M
The M phase is known as mitosis and has 5 sub stages
Phases of the cell cycle
1) As soon as a cell is born it can exit the cell cycle and start to differentiate/ mature/
specialise
2) Enter the G0 stage (quiescence)
Inactivity or dormancy (still alive)
Stem cells sometimes remain in G0
Phases: As soon as a cell is born, it can
1) Move into the G1 phase known as the gap phase. Cells can synthesise proteins, grow
and perform functions
2) S stage- ( known as the synthesis phase). Copies are made of genomic DNA and
centrioles . Nuclear content doubles (replication)
3) Gap phase 2 - Checks accuracy of DNA replication and repairs damage. Synthesises
enzymes needed for M phase
4) Mitosis- The five sub stages of cell division are performed. Each one of the two DNA
copies is packed into the new nuclei and cell membrane divides
How do we observe cell division?
- Histological (immunohistochemistry- IHC) markers are a staple of pathology and cell
biology
Different markers for different phases: Proliferation
Marking G1, S, G2, M
Ki67 IHC marker
KI67 is a nuclear protein, hence brown areas represent the cell nucleus
G0 cells are unmarked
Grades and the Ki-67 index
The grade of a large bowel or rectal neuroendocrine tumour (NET) tells you how much the cells
look like normal cells under a microscope . It gives you and idea of how the tumour might
behave when it spreads
There are different ways to grade NETs in the Uk use a system created by the World Health
Organization (WHO) which is divided into 3 different groups
- Grade 1 (NET G1 or WHO 1)
