characteristics of stem cells
1) unspecialised - differentiate
2) self-renewal when cells specialise to replace
what 2 things cause differentiation
1) external signals - chemical signals from cells
2) internal signals - gene expression
stem cell potency levels
- totipotent - single cell makes entire individual (all cells), can self renew (no limit)
- pluripotent - embryonic cells, can form 3 germ layers (endoderm, ectoderm, mesoderm
3.multipotent - adult stem cells, multiple but limited cells -> limited ability to divide, proginator cells - unipotent - slef-renew, one cell type possible, muscle and epithelial stem cells
what is the final cell type of stem cells
terminally differentiated = mature blood cells
how could stem cells be used for cloning
- take DNA from a mature non-stem cell
- place into a totipotent cell and allow to differentiate into entire organism
what is cancer
- a mass of cells capable of uncontorlled growth
- lack cell cycle control
- can spread
types of cancer and what they affect
- carcinoma = epithelial cells (90% cancer)
- Sarcoma = supporting tissues e.g. bone tissue
- Lymphoma and leukemia = blood cells and lympathic cells
causes of cancer
1) activation of oncogenes -> proto-oncogenes are genes that allow cell division, if damaged, can form oncogenes that cause cancers
2) loss of antioncogenes - regulate cell cycle and repair DNA, loss = survival of cancer cells
3) spontaneous mutation
4) genetics
5) oncoviruses - insertion of oncogenic genes via virus
6) carcinogens - cause DNA damage
process of carcinogenesis
- initiation = event changes normal cell to precancerous cell (sensitive)
- promotion = repeated exposure to cancer causing agents
- tumor progression = loss of normal ploriferation control
benign vs malignant tumors
benign - confined to local area, rarely dangerous
malignant - invade surrounding tissues, bloodstream, travel through body
invasion vs metastasis
invasion = migration of cancer cells into adjacent tissues
metastasis = ability of cancer cells into blood and lymphatic system
where does blood orginiate
mesoderm
how much blood do humans have
5-7L
how much of blood is ells and plasma
cells = 40%
plasma = 60%
what is plasma vs serum
plasma = liquid component of non-clotted blood
serum = liquid component of blood after clotting
types of blood cells
- red = O2
- platelates = clotting
- white = immune protection
funtions of blood
1) transport
2) comunication - hormones
3) regulation - homesostasis
4) protection - wound healing, infections (clotting)
how can blood regulate temp
- vasodilation and constriction
how does blood clot
- platelets in blood connect to broken connective tissue and release clotting factors
- clotting factors = secondary haemosasis -> strengthen clot
what cells have no nucleus
- RBC, platelets
5 types of white blood cells
1) monocyte
2) lymphocyte
3) eosinophyls
4) neutrophils
5) basophils
what cells do have a nucleus
all white blood cells
what is the abundance of each blood cells
neutrophils = most
lymphocutes
monocytes
eosinophils
basophils
what is blood stained with
blue = haematoxylin - neg molecules
red - eosin, pos molecules
