topic 8 - final exam !! Flashcards
Understand the role of stem cells in normal development.
Stem cells are a special type of cells that have two important properties. They are able to make more cells like themselves. That is, they self-renew. And they can become other cells that do different things in a process known as differentiation. Stem cells are found in almost all tissues of the body. And they are needed for the maintenance of tissue as well as for repair after injury.
Compare the characteristics of stem and differentiated cells
Cells differentiate to specialize for different functions. Germ line cells are any line of cells that give rise to gametes—eggs and sperm—and thus are continuous through the generations. Stem cells, on the other hand, have the ability to divide for indefinite periods and to give rise to specialized cells.
LLO8.3 Compare the characteristics of healthy stem & differentiated cells with cancer cells
Healthy state
Where there is a balance between cell death and cell renewal
Carcinogenesis
Cell renewal exceeds cell death and more than what the body needs
Understand the changes to cells that make them cancerous.
activations of onocogenes- promotors of cell divisions
- Oncogene – cancer causing gene
- Multiple mechanisms of oncogene activation
Duplication of normal gene that promotes cell division
Mutation leading to the expression of a constitutively active mutant protein – BCR-ABL kinase
Loss of anti-oncogenes - Cell cycle regulators
- DNA replair genes
- Loass permits survival of mutant cells – cells do not respond to apoptosis signals or inhibitory effects of surrounding cells
Spontaneous DNA mutation
- Point mutations leading to activation
- Chromosomal rearrangements
Genetics
- Rarely directly inherited
- Associated with mutations in gene that increase susceptibility to cancer
Oncoviruses
- Insertion or enhancement of oncogenic gene
- Human papilloma virus (HPV), epstien Barr virus (EBV)
Carcinogens
- Substances that cause DNA damage or alter cell processes
- Radiation asbestos, tobacco smoke
Identify the major cell types of blood & be aware of their relative proportions.
WBC- 4%
RBC- 41%
Plasma – 55%
Platelets – 0.01%
what is the proportion of WBC in a healthy individual
Neutrophils 60%
Lymphocytes 30%
Monocytes 5%
Eosinophils 3%
Basophils 0.5%
Describe the function of the major cell types of blood & what may influence their relative numbers.
- Transport
- * Blood transports substances around body
- * O2 and nutrients to tissues
- * CO2 and waste products away from tissues
- * Hormones from endocrine glands to target
- tissues - Communication
- Hormones generated in glandular tissue are transported to target tissues via the blood
- Endocrine system
- Eg stimulation of Erythropoietin (EPO) production in low o2 environments
- Low blood o2 detected in kidneys – epo produced
- Epo travels to bone marrow via blood
- Stimulates stem cells to increase RBC production
- Increase blood capacity to transport o2
- Epo production reduces again - Biochemical homeostasis
Body temp
- Blood helps maintain body tem
- Removes heat from active tissues and transports to skin for dissipation
- Vasodialation/ constriction regulate heat dissipation and vasoconstriction
PH
- * pH maintained 7.35 – 7.45
- * Largely controlled by bicarbonate buffer system
- * Carbonic anhydrase
Electrolytes/Volume
- * Kidneys filter blood
- * Entire volume ~20-25 times per day
- * Remove waste products and excess fluid - Protection
Wound healing
- Blood contains Platelets and clotting factors
- * Platelets – involved in primary clotting
- * Clotting factors - present in the blood and are activated post injury
- * Deficient in haemophilia
- * Prevents blood loss after injury
Infections
Blood cells and their products provide defence against viruses, parasites, bacteria
- WBC – many types and mechanisms
- Phagocytes engulf and destroy microbes
- Antibodies bind and neutralise pathogens
what’s the process of differentiation of blood cells from stem cells
hematopoiesis
Describe different modes of communication and transport within and between cells.
- Direct – via cell junctions and cel-tocell contact
- Local – autocrine and paracrine hormone signalling and synaptic signalling
- Long didtance – endocrine (hormone) signaling
Recognise the role of hormones/ligands and receptors in communication pathways.
Hormones
- Molecule produced in one tissue that can cause a change in another
- Carries a signal and has an effect at the cellular level @chemicla messgengers
- Characteristics of hormones:
Secreted into bodily fluids (eg blood)
Bind to specific receptors on/in target cells
Initiate changed in cellular activity
Are degraded by secific enzymes
Ligand a molecule that binds a specigic receptor therby initiating a response eg hormones but can also be molecules such as sugars, ions ect
Receptors
- Proteins that binding ligand (including hormones)
- Multple types
- Varitey of cellular sites
- Cell wall – insulin recptors
- Nucleus – oestrogen receptor
- Tissue specific expression of receptors restrics effects of hormones to recptor bearing (target) cells.
Examine how comparing genomes may lead to the identification of drug targets and how Pharmacogenomics can explain variations in response to therapies.
- Identifying the genetic differences etween us and pathoogens can define nre drug targets
- Comparing the genes of rsistant and senitive organisms can identify the cause of resistance
- Candidate gene – direct sequencing
- Unknown – whole genome sequencing
- Pharmacogenomics – study of how variations in genetic makeup results in organisms/individuals responding differntly to compunds, environments ect
- Identifying differences between us and pathogens allows for the development of pathogen specific compounds- DRUGS!
Review how the genetic cause of diseases may be identified using genomic methods and how this may influence disease diagnosis and treatment.
Some cancers have stonf genetic component
Example: breast cancers and BRCA 1 and 2 mutations
- BRACA genes encode DNA repair proteins
- Mutations in these genes that give rise to non-functional proteins reducing capacity for DNA repair becomes
- Therefore, mutations accumulate in the DNA
- These mutation can cause uncontrilled cell proliferation or cancer
Genetic testing by sequencing BRCA1 and BRCA2
- BRCA 1 and 2 mutation can increase the risk of developing:
1. Breasts
2. Ovarian
3. Pancreatic
4. Prostate
- It is now possible to be screened for mutations in these genes
Personalised medicine- targeting therapy to patient needs
Estrogen binds to the estrogen receptor (ER) and is “pro-growth” for
Breast cancer.
Compare the characteristics of Cilia and Flagella using the pull down options
cilia
- many per cell
- cell remains stationary fluid moves
- length of 2-10um
flagella
- <3 per cell
- structure drives cell through fluid
- length 10-200um
charcteristic of each WBC
nucelar morphology, cytoplasm, granules and function
neutrophil
- multilbed
- pale
- present but neutral stain
- fight infection heal injuries
lymphocyte
- mostly circular
- basophilic
- none
- adaptive immunity - B cell produce antibodies, T cells anti virus
monocyte
- large and eccentric
- basophilic
- none
- general phagocytosis
eosinophil
- multilobed
- esinophilic
- present, pink/eosinphilic
- defent against parasites
basophil
- multi lobed
- basophilic
- present, blue/basophilic
- allergic response - release histamine
compare the characterisitcs of stem, mature and cancer cells - based on their capacity for self renewal , potency to differentiate into differnt cell types
and specialisation
stem
- infinite
- high
-low
mature
- none/limited
- none
-high
cancer
- infinite
- very limited
- variable
