Week 2 - Changing Body & Brain 2024 Student PDF

Week 2: The 3012PS changing body and Y brain Learning Outcomes 1. Describe 3 theories of ageing 2. Understand the major factors in primary ageing of the body including: a) Appearance and mobility b) Sensory c) Vital systems 3. Critically engage in psychological implica...

Week 2: The 3012PS changing body and Y brain Learning Outcomes 1. Describe 3 theories of ageing 2. Understand the major factors in primary ageing of the body including: a) Appearance and mobility b) Sensory c) Vital systems 3. Critically engage in psychological implications of primary ageing 4. Understand the 3 main parts related to primary ageing of the brain Mini-Lecture 2.2: Week 2 Theories of 3012PS Ageing Y Reasons why we age Non-stochastic / Programmed factors - ageing follows a biological timetable which is driven by genetically regulated processes Stochastic / Damage-related factors - ageing results from a continuous process of damage accumulation originating in by- products of metabolism Metabolic / Rate of Living Theories The faster your metabolism, the shorter your lifespan  Limited energy  Hormonal regulatory system adaptation to stress  Excess calories Cellular Theories Limited number of times a cell can divide: Hayflick limit  Telomeres adjust the cell’s response to stress and growth by shortening with each cell replication  The enzyme telomerase is needed in DNA replication to fully reproduce the telomeres when cells divide. But telomerase normally is not present in somatic cells, so with each replication the telomeres become shorter. Eventually, the chromosomes become unstable and cannot function. Cellular Theories Wear and tear  Tissues become worn out Cross-linking  Tissue becomes stiffer with age Free radicals  Reactive chemicals causing cellular damage Genetic Programming  Ageing may be programmed into genetic code  Cells pre-programmed to self-destruct  Apoptosis - genetically motivated process of programmed cell death where a cell is carefully sectionalized, and its fragments can be used by other cells as a building material Genes and Ageing Genes can increase or decrease longevity in complicated ways  A single gene mutation in worms can extend lifespan by almost 10-fold  There is a significant degree of heritability of longevity, in particular at later ages  The offspring of long-lived parents are protected against age-related diseases Genetic Disorders and Ageing Rare genetic diseases that manifest in ‘accelerated ageing’ Werner's (WS), Cockayne, and Hutchinson-Gilford's (progeria) syndrome Comparable to ageing 8x faster than normal Helpful Definitions Ageing is a complex process composed of several features: 1. An exponential increase in mortality 2. Physiological changes that typically lead to a functional decline with age 3. Increased susceptibility to certain diseases Life expectancy is how long one is expected to live Longevity is the period of time one is expected to live under ideal circumstances Lifespan is the period of time in which life events typically occur WHAT HAPPENS The good and the bad behind AS WE AGE ageing Appearance and Mobility Skin Hair Voice Body Build Mobility Appearance and Mobility Skin Hair Voice Body Build Mobility Appearance and Mobility Skin Hair Voice Body Build Mobility Appearance and Mobility Skin Hair Voice Body Build Mobility Appearance and Mobility Skin Hair Voice Body Build Mobility Sensory Systems Vision Hearing Somesthesia and Balance Taste and Smell Sensory Systems Vision Hearing Somesthesia and Balance Taste and Smell Sensory Systems Vision Hearing Somesthesia and Balance Taste and Smell Sensory Systems Vision Hearing Somesthesia and Balance Taste and Smell Psychologica l Implications ? Mini-Lecture 2.4: Week 2 3012PS Vital Systems Y Vital Functions Cardiovascular System Respiratory Diseases Reproductive System The Autonomic Nervous System Vital Functions Cardiovascular System Respiratory System Reproductive System The Autonomic Nervous System Vital Functions Cardiovascular System Respiratory Diseases Reproductive System The Autonomic Nervous System Vital Functions Cardiovascular System Respiratory Diseases Reproductive System The Autonomic Nervous System Mini-Lecture 2.5: Week 2 3012PS Brain Changes Y  The Brain Brain is made up of neurons  Neurons consist of dendrites, axon, neurofibers, terminal branches.  Neurotransmitter s travel across the synapse. The 3 major changes in the brain with ageing 1. Neurons 2. Neurotransmitters 3. Brain structure Neurons and Ageing  Number of neurons declines  Number and size of dendrites decreases  Tangles develop in axon fibers  Increases in deposits of proteins  Number of synapses decreases White matter hyperintensities (WMH)  White matter refers to neurons that are covered by myelin that serve to transmit information from one part of the cerebral cortex to other parts of the brain.  WMH appears on MRI images as lesions with a bright, spotty appearance.  WMH linked to dementia and stroke.  White matter shows some general decline with age. Neurotransmitters and Ageing Dopamine declines, this is associated with higher–level cognitive functioning, so declines are related to poorer memory and cognition Serotonin and acetylcholine also decline with age (mood, sleep, appetite, arousal, sensory perception) Brain Structure and Ageing  Considerable shrinkage occurs in the brain  Especially in prefrontal cortex, hippocampus and cerebellum Impacts of Brain Changes Executive Functioning  Difficulty focusing solely on relevant information  Reduced volume of prefrontal cortex Memory  Specific structural changes (e.g., the hippocampus) result in memory decline Emotion  Increased processing of positive emotional information with age  Better emotion regulation with age Explaining Age-related Brain Changes In adults there is greater activation in different brain regions, as well as for the different patterns within the prefrontal cortex – which could be because additional brain regions are being used in order to successfully execute cognitive functions as one grows older The Parieto-Frontal Integration Theory (P-FIT) - proposes that intelligence comes from a distributed and integrated network of neurons in the parietal and frontal areas of the brain Explaining Age- related Brain Changes 1. CRUNCH (compensation-related utilization of neural circuits hypothesis) 2. STAC-r (scaffolding theory of cognitive age revised) PLASTICITY AND PREVENTION OF BRAIN DECLINE Summary 1. Describe 3 theories of ageing 2. Understand the major factors in primary ageing of the body including: a) Appearance and mobility b) Sensory c) Vital systems 3. Critically engage in psychological implications of primary ageing 4. Understand the 3 main parts to primary ageing of the brain