Tissue Homeostasis Flashcards
What can uncontrolled proliferation lead to
Cancer multiplying
What does not enough proliferation lead to
Can’t replace cells
What is apoptosis
Cell death
What are the 6 stages of mitosis
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis - part of telophase
What happens in interphase
Nucleolus and nuclear envelope are distinct and the chromosomes are in threadlike form chromatin
What happens in prophase
Chromosomes appear condensed nuclear envelope in not apparent
What happens in metaphase
Thick coiled chromosomes each with two chromatids are lined up on the metaphase plate
What happens in anaphase
Chromatids have separated and move towards the poles
What happens in telophase
Chromosomes are at the poles becoming more diffuse nuclear envelope reforms cytoplasm may be dividing
What is cytokinesis
Division into two daughter cells is completed
What causes DNA damage or loss
Ionising radiation
Chemotherapy
Free radicals
What does energy failure cause
Lack of oxygen
Lack of glucose
Mitochondrial failure
What does mechanical disruption cause
Trauma
Osmotic pressure
What does membrane damage cause
Free radicals
What does failure of membrane functional integrity cause
Damage to ion pumps
Complement or perforin
Bacterial toxins
What does blockage of metabolic pathways cause
Interruption of protein synthesis
Respiratory poisons
Hormone/growth factor lack
What does insufficient carbohydrate lead to
Cannot make ATP which most cell repair and maintenance mechanisms rely on
What does insufficient protein lead to
Not enough amino acids to make proteins
What do vitamin deficiencies lead to
Various effects including scurvy (vitamin C) where patients can’t cross link collagen leading to tissue damage
What does calorie surplus lead to
Obesity e.g. inflammation
What is autophagy
Cells can end up ‘eating themselves’
What ischemia
Lack of blood supply so oxygen is cut off no ATP cell injury
What is reperfusion
When the blood supply and oxygen comes back
How does novichok nerve agent work
Organophosphate acetylcholine esterase inhibitor
Works by increasing ACh at NMJ, muscle contract, respiratory and cardiac arrest are possible
Can treat with atropine
What is atrophy
Cells become smaller
Fewer organelles and reduced function
What is hypertrophy
Cells become bigger
Same number of cells
Can improve function and be adaptive
Can be pathological
What is hyperplasia
Cells proliferate increase in number in response to increased demand
What is metaplasia
Cells change from one type to another
Reversible
Is benign
What is dysplasia
Cells change into a pathologically abnormal form
What is necrosis
Pathological cell death
Cell membrane loses integrity and cell contents leak out
What is apoptosis
Programmed cell death
Prevent tumour development
Part of healthy tissue homeostasis
What are the 2 pathways for apoptosis
Intrinsic and extrinsic
