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Ageing - Coggle Diagram
Ageing
Heart
ECG (elecrocardiograph) - records electrical signals from the heart
P wave - depolarization of atrio
QRS complex - depolarization of ventricles
T wave - repolarization of ventricles
electrical signals
purkinje fibres - cause ventricles to depolarize
branches of HIS sends signal to the left and right branch which send the signal to purkinje fibres
AV node (atrioventricular) - sends the signal to branches of HIS (from atria to ventricles)
SA node (sinoatrial) - generates electrical signal that causes the atria to depolarize and then sent to AV node
anatomy
Left and Right Atria: The upper chambers of the heart (receive blood from the body)
Left and Right Ventricles: The lower chambers of the heart (pump blood to the body)
Aorta: The largest artery in the body, which carries blood from the heart to the circulatory system
Pulmonary Veins: Blood vessels that carry oxygen-rich blood from the lungs to the heart
Valves: Prevent backward flow of blood
Tricuspid Valve: between right atrium and right ventricle
Pulmonary Valve: between right ventricle and pulmonary veins
Mitral Valve: between left atrium and left ventricle
Aortic Valve: between left atrium and aorta
heart failure - ventricles fail to depolarize
cardiac arrest - caused by malfunctioning electrical signals
nerves
sympathetic - increases rate of depolarization of SA node + increase excitability of cardiac cells + increase contractility of atrial muscle
parasympathetic - decreases the rate of depolarization of SA node + decreases excitability of cardiac cells
heart attack - caused by clogged arteries
Heart conditions
Arrhythmia: abnormal timing or contraction of the heart
Ventricular Tachycardia: lower chambers beats too fast
Tachycardia: resting heart rate above 100 bpm
Bradycardia: resting heart rate below 60 bpm
Atrial Fibrillation: atria contract fast than 350 bpm
Ventricular Fibrillation: ventricles contract faster than 350 bpm
Cancer
types
benign tumour - can't spread
malignant tumour - can spread
metastases - derivatives (descendants) of tumor around the body
origin
enhanced telomerase activity
mutations accumulate (with age) in crucial genes (which encode cyclins / cell cycle)
interphase is shortened (growth is insufficient)
treatment
stem cells replacement (restricted) - leukemia with bone marrow being replaced
chemotherapy - medicine (drug) which targets spindle or microtubules (as a rule), thus stopping fast dividing cells (including hair follicle cells, intestine cells, etc) = common side effect - hairloss, vomiting
radiation (targeted)
surgery
diagnosis
CT scan - computer tomography
MRI - magnite resonance tomography
blood chemistry (men need to check reach 40+ yo prostate cancer)
biopsy
chest X-ray
death
cerebral death
cardiac arrest
organ / tissue donation and bioengineering
Alzheimers and Dementia
Understanding Alzheimers and Dementia
Dementia: Umbrella term for memory loss disorders (?)
60-70% of people who have dementia have Alzheimer's Disease (37% people >85%, 75-84 43%)
Symptoms: Memory loss, Difficulty in completing familiar tasks, recurring confusion, planning and solving easy as well as difficult problems, Aphasia, personality changes, Impaired movements
Physiology
Alzheimer's Disease: Abnormal structures, such as Plaques and Tangles (diseased neuronal axon), surround the diseased neuron, vastly smaller hippocampus, Enlarged ventricles, shriveled cerebral cortex
Treatments (will not prevent but will reduce symptoms): Donepezil, Namenda, Leqembi
Preventive measures and risk reductions: Eat healthy, stay physically active, stay social, keep learning, stay curious, engage in mental stimulation, manage stress, prioritize stress, get regular health check-ups, stay hydrate
Cell
Cell division
Cell senescense
Hayflick limit
40-70 times
Telomeres and telomerase
end replication problem in linear chromosomes - 1 - DNA strands are antiparallel, 2 - there are 2 options: 5' / 3' end. 3. for each of them replication is a little different (!!!!) - in one of them replication can't be complited fully because of the requirements of enzymes
contain repetitive DNA sequences + do not contain genes
telomerase - enzyme in cells which is reverse transcriptase, it has RNA sequence which is complimentary to telomere's repetitive sequences, thus allowing it to build up the telomere DNA by using this sequence as a template
protect DNA genes when replication occurs, protect chromosomes from merging, acts as a molecular clock (the entire length of telomere determines cell's lifespan, shortening equally with each division and thus acting as a clock which counts the number of divisions left until the telomere fully degrades and cell undergoes apoptosis)
Apoptosis
programmed cell death when a cell is damaged beyond repair (DNA mutations, chromosomes mutations, cell cycle aberrations, organells mulfunctioning, etc.)
shaping certain body parts during embryogenesis
Cell cycle
Mitosis
G0
why?
hasn't passed G1 checkpoint
differentiate terminally (get the phenotype of a specific morphology (shape)) to operate according to their function (produce hormones / proteins / enzymes / propagate electric signal / contract)
in oocytosis for arrest oocyte division until the reproductive age
Checkpoints
G1
Check that environment is favourable for undergoing division
G2
check that DNA was replicated correctly
M
spindle check - microtubules and chromosomes' allignment
factors
external
anchorage is necessary for division
density-dependance (cells stop division if there's no room)
nutrients
hormons
cell-cell communication
internal
growth factors
organells, checkpoints passed
cytogenetics
chromosomes - highly condensed chromatin visible during cell division
DNA (double helix), nucleosomes beads, loops, chromosome
each chromosome has a distinctive territory
chromosomes can be anchored at lamin - protein layer underlying nuclear membrane (disrupted in Progeria disease - makes a faulty lamin, thus the shape of nucleus changes, thus chromosomes attachement and territory are affected, and this changes the pattern of gene regulation
chromatin = DNA + proteins (histones)
chromatid - one strand of DNA occured after replication and coupled with second strand making up a chromosome
Meiosis
General Understanding
Cell division to create gametes (Eggs and Sperm)
Genetic Variation happens through crossing over, when the chromosomes exchange pieces of DNA
Meiosis produces genetically unique haploid cells (gametes)
Reduces the chromosome number by half (from diploid to haploid)
Phases
Meiosis I
Metaphase I: Homologous pairs align at metaphase plate. Independent assortment occurs. Microtubules attach to centromeres of each homologous pair and pull homologs apart from each other.
Independent assortment: Homologous chromosomes will be randomly distributed to daughter cells.
Anaphase I: Homologous pairs are still being pulled apart
Telophase I & Cytokinesis: Homologs are at opposite ends of the cell and microtubules are broken down completely. The cell forms a cleavage furrow due to actin and myosin interaction during cytokinesis. Nuclear envelope forms. Chromosomes decondense. No interphase between Meiosis I & II.
Prophase I: The nuclear envelope breaks down. Chromosomes condense. Synapsis and crossing over occurs between homologous chromosome pairs. Centrosomes move towards opposite ends of the cell and formation of microtubules.
Crossing over: The process of exchanging parts of chromosome between non-sister chromatids. Can only be performed at chiasmata
Chiasmata: Point of connection between homologous chromosomes.
1 more item...
Meiosis II
Prophase II: The nuclear envelope breaks down. Chromosomes condense. Centrosomes move towards opposite ends of the cell. Formation of microtubules
Metaphase II: Chromosomes align at metaphase plate. Microtubules attach to centromeres of chromosome and pull sister chromatids apart from each other.
Anaphase II: Sister chromatids are still being pulled apart
Telophase II & Cytokinesis: Sister chromatids are at opposite ends of the cell and microtubules are broken down completely. The cell forms a cleavage furrow due to actin and myosin interaction during cytokinesis. Nuclear envelope forms. Chromosomes decondense. Daughter cell becomes haploid.
Mutations
Hereditary mutations: Gremlins mutations (present in the parent's egg or sperm cell)
Acquired (somatic) mutations: present in only certain cells, not every cell in the body. Changes cause by environmental factors can occur if a mistake is made as DNA copies itself during cell division.
Copy Number Variation (CNV): when number of copies varies ; a person can be born with one, three, or more copies of particular genes (we usually have two copies of most genes, one from each parent)
Changes in chromosome structure
Translocation: piece of one chromosome breaks off and attaches to another chromosome
Deletion: chromosome breaks and some genetic material is lost
Duplications: part of a chromosome is copied (duplicated) too many times
Inversion: breakage of chromosome in two places; resulting piece of DNA is reversed and re-inserted into the chromosome
Isochromosome: chromosome with two identical arms (instead of one long arm and one short arm) = isochromosome has either 2 short or 2 long arms
Dicentric chromosomes: has 2 centromeres. ; from the abnormal fusion of two chromosome pieces.
Ring Chromosomes: when chromosome breaks in two places and the ends of chromosome arms fuse together to form a circular structure / doen not have centromere
Kinds of Mutations
Missense mutation: substitution of one amino acid for another in the protein made by gene
Nonsense Mutation: altered DNA signals cell to stop building a protein
Insertion: changes number of DNA bases by adding piece of DNA
Deletion: removing a piece of DNA
Duplication: piece of DNA is abnormally copied one or more times
Frameshift mutation: DNA sequence has an insertion or deletion of nucleotides that shifts the "reading frame" of the genetic code. This change affects how the sequence is read in groups of three (codons)
stem cells
ESC + iPSC (reprogramming)
types
totipotent
pluripotent
multipotent
unipotent
cloning = nuclear transplantation
produce one or more organisms that are genetically identical to the parent that donated the single cell.
remove the nucleus of an egg (enucleated egg).
take out a nucleus from a differentiated cell of another organism
transplant an egg to a surrogate mother (reproductive cloning)
reproductive cloning - cloning results in birth of a new identical to a nucleus donor organism
Dolly - problems - premature disease-driven death (arthritis + lung infection) - because of incomplete reprogramming (epigenetics? or telomeres were too short?)
sometimes cloned animals aren't identical 100% (fur colour pattern was different) - explanation - X-chromosome inactivation (mosaicism) - dosage compensation
epigenetical changes - restructuring in chromatin - acetylation of histones or DNA methylation - it interferes with pattern of gene expression necessary for normal development
therapeutic cloning - form stem cells for patients' treatment
Gurdon experiment with frog - if we transfer a nucleus from a differentiated cell, the embryo development will not be full, it will stop at some stage, without developing to an organism, while if we take a nucleus from an embryonic cell, we get the viable clone (tappole) = sth in a differentiated nucleus is blocking / preventing = this nucleus is not the same as embryonic cell nucleus (sth changed)
put the nucleus from step 2 to an egg from step 1
enhanced telomerase activity
Brain
EEG (electroencephalogram)
Record electrical activity in brain - Electrical signals are converted into brain waves
electrodes placed on the scalp in a specific sequence to measure activity from different parts of the brain * 10-20 formation (21 total electrodes)
signals are amplified and recorded, data is inputted to form a graph
Applications of EEG in medical field: medical diagnostics, cognitive research, neuro- feedback (learning to control brainwaves to feel less negative)
Limitations:
Poor accuracy to pinpoint where brain activity is happening
Electrical signals from other sources can interfere with data collection (example: muscle contraction, stomach contractions)
Brain Waves
Electrical patterns produced by the brain
factors that influence brain waves: mental state, your activity and your consciousness level
Delta Waves: slowest brainwave (0.5-4 Hz) , helps memory
Theta Waves: found in sleep , helps you become more creative 4-8 Hz
Alpha waves: 8-12Hz, found during relaxed state while awake, help with memory and creativity
Beta waves: 12-13 Hz, found during wakefulness while engaged in semi-challenging activity, helps with memory and problem solving
Gamma waves: fastest wave 30-80 Hz , found during high alertness during consciousness , helps concentration/ alertness / creativity / intense focus
General terms and observations
theories of ageing
dormant viruses - retroviruses which got into cells (by endocytosis), convert their RNA to DNA (reverse transcription - reverse transcriptase) and insert their DNA randomly in our genome (= in any gene or interspace between coding genes), which can disrupt cell cycle, or other pathways by introducing mutations thus possibly accelerating cell senescence / cancer / apoptosis / etc.
oxidative stress - free radicals attack DNA (lipids, RNA, proteins), damaging them and causing cell senescence etc.
chronic inflammation and immune system getting weaker with age (or against our body and attacks our cells)
programmed aging - genes determine if we live much longer than 80 yo (% high), but environment has more impact in living up to 80
Nobel Prizes
iPSC (Gurdon + Yamanaka) - induce 4 genes to adult somatic cell with retroviruses = reprogramming (can't make humans by this method, but can study and treat diseases with these stem cells)
Depression and ADHD
What is Depression / ADHD
Depression: Mental disorder experiences intense long periods of negativity
Imbalances in neurotransmitter
Cortisol overload, overactivity of amygdala, reduced prefrontal cortex activity
Causes: Genetics, Brain chemistry, life events, substance abuse, loneliness
Medications: SSRI, SNRI, Dopamine Reuptake Inhibitors
Makes you feel like vegetable; slower cognitive functions: brain is adjusting to the foreign aid from the medication
ADHD
Neurodevelopmental disorder: Inattentive and/or hyperactive and/or impulsive behavior
Brain structure and functions, birth related factors (premature birth)
Medications
Non-Stimulants: Atoxemine
Stimulants: Methylphenidate Ritalin, Adderall
Multiple sclerosis & Parkinsons
What is it
Multiple Sclerosis: Immune system attacks myelin sheath
Neurons die faster or defective transfer of signals
Vision loss, muscle fatigue, etc.
Risk Genetic, smoking, limited sunlight exposure, etc.
Diagnose method: MRI check, Spinal fluid analysis
Treatment: medicine, plasma exchange
impaired Balance, slowed movements, tremors, rigidity
Unknown causes. Age, brain injury, exposure to toxins
Prevention: Exercise, Coffee, Smoking
Diagnosis: Mental status, cranial nerves, motor system, deep tendons reflexes, pathological reflexes, sensory system, cerebellum,
Treatment: Trying out different types of Medicine, Deep brain surgery, Exercise, healthy diet
