Life Sci 2L03 Lab Test

Aging

Universal process in all organisms that is inevitable and varies by individual

Aging definitions

chronological, biological, apparent, psychological, social

True or false: Our body's cells and tissues all age at the same rate.

False. Some divide every few days and others live in body through the span of entire life

What is aging influenced by?

Genetics and environmental factors

What does aging yield

Decreased adaptability to internal and external stressors
Increased vulnerability to fraility, disease, and mortality

True or false: rates of bodily aging vary from person to person

True

hallmarks of aging

-altered intercellular communication
-genomic instability
-telomere attrition
-epigenetic alterations
-loss of proteostasis
-deregulated nutrient sensing
-mitochondrial dysfunction
-cellular senescence
-stem cell exhaustion

True or false: cellular senescence is a hallmark of genetic aging

False

cellular senescence

Cells lose their ability to replicate, while metabolic processes continue

Changes in environment, nutrition and medical care have ______ the expected/average age of survival

Extended

Frailty

Increased vulnerability to adverse health outcomes

What does frailty result from

Aging associated decline in multiple physiological systems

Domains and Impairments of frailty

Physical - low grip strength, low physical activity, sarcopenia
Nutritional - low energy, unintentional weight loss, dysregulated energetics
Sensory - reflexes, gait, balance deficits
Cognitive - attention deficits

Sarcopenia

Loss of muscle mass and strength

Dysregulated energetics

Decreased energy production or increased utilization

Ways of assessing frailty

- frailty phenotype
- frailty index

frailty phenotype

- Frail presence of 3 or more of the following: weight loss/shrinking, weakness, poor endurance, slowness, low physical activity
- pre-frail: presence of 1 or 2 deficits
- not frail: absence of deficit

Frailty index

Expressed as ratio of deficits present to total number of deficits

Frailty index and frailty phenotype

Complement each other

Tests used to assess frailty

Short performance physical battery tests
Mini-mental state exam (MMSE)

Short Performance Physical Battery

To stimulate physical symptoms of frailty
1. Romberg balance test
2. Gait speed test
3. Chair stand test

Mini-Mental State Examination (MMSE)

To stimulate neurological symptoms of frailty. Assess mental status using 5 areas of cognitive function
- orientation, registration, attention, recall, language

Aging and frailty equipment

- knee wrap (affect balance and gait speed)
- over shoes (affect balance)
- back brace (affect balance and gait speed)
- Headphone (stimulate tinnitus)
- simulation goggles (Stimulate glaucoma)
- simulation glasses (Stimulate cataracts)

MMSE
- gloves (affected dexterity)
- glasses
- goggles
- cotton balls (muffle hearing)

Bar Graph vs. Scatterplot

Bar graph - measure differences and relay info regarding different IV
Scatterplot - used to look for trend between 2 variables

Requirements of graphs

- black or grey
- tick marks (major outside)
- labels
- error bars

How to add error bars in excel graph

- calculate std dev
- click error bars
- more options > custom > specify calculated std dev

How does the flu spread

Respiratory droplets projected when infected people cough and sneeze that are inhaled when we breathe

How long can flu remain infectious on surfaces

24 hours

Flu symptoms

Fever, chills, cough, body aches

How long do flu symptoms last?

5-7 days

When do flu symptoms begin

1-2 days after becoming infectious

reproduction number (R0)

The number of subsequent infections in a susceptible population caused by a viral illness in one individual during its infective period

If R0 < 1

infection fails to spread

If R0 >1

infection will spread

attack rate

percentage of people who become ill in population after exposure

What factors does speed of virus spread depend on

- characteristics of virus and infected hosts

Flu vulnerable groups

Pregnant women
Children under 5
People with chronic medical conditions
People with immunosuppressive conditions
Health care workers
Seniors (>65)

Ways to limit flu

- vaccine
- washing hands + other hygiene
- quarantine
- antivirals

immunosenescence

The immune system works less well as we age. Senescence of the cells in the immune system

When do vaccines become less effective

Over age 65

Epidemiology

Branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people.

SEIR model

Transmission of disease. Follows: susceptible > exposed > infected > recovered

Affected population

Number of infected + number recovered

% affected

(# infected + # recovered)/(initial population) x 100

Seroconversion

The window of time from when an individual is vaccine and producing antibodies but does not yet have immunity

Strategies for outbreak control

- vaccination
- isolation
- antivirals

Nerve vs. Neuron

Neuron = single cell.
Nerve = branch with many cells (neurons).

Neuron Classification

- input (sensory, interneuron, motor neuron)
- anatomy (monopolar, bipolar, multipolar)
- location (central, peripheral)
- transmitter produced (serotonergic, dopaminergic)
- Relationship to another neuron (presynaptic, postsynaptic)

presynaptic neuron

neuron that sends the signal

postsynaptic neuron

the neuron on the receiving end of the synapse

Types of neural signals

Internal
Neuron-to-neuron

internal signals

Electrical signals
- action potentials - sodium/potassium spikes
- graded potentials
- plateau potentials

Neuron-to-neuron signals

Chemical signals - delivered by vesicles across
- neurotransmitters

Electrical signals
- electrical synapses
- emphatic signalling

Membrane potential

Inside of neuron has more negative charge than outside when neuron is inactive

What is neural activity affected by

Changing the voltage of the membrane potential

Spatial summation

Activity of MULTIPLE presynaptic neurons combine to change postsynaptic neuron

Temporal summation

SINGLE presynaptic neuron firing multiple action potentials to change postsynaptic neuron

What between neurons is important for function

Connection

Why is neurotransmitter type irrelevant to function

Receptors determine responses of target neuron

Aging impact on neurons

- fewer neurons
- fewer synaptic connections
-les synaptic plasticity
- greater risk of neurodegenerative disease
- accumulated risk of injury over time

Ganglia

Clusters of nerve cell bodies

What is used to distinguish strong external stimulus from weak

Pattern and frequency of action potentials

T-test

Statistical hypothesis that determines whether there is a statistical difference between the means of two groups

Assumptions of a t-test

- data must be continuous or ordinal
- data is selected randomly
- data is representative of general population
- data when plotted follows a normal distribution
- large sample size (over 30 usually)
- homogeneity of variance

Types of T-tests

- independent one sample
- independent two sample
- paired t test

Independent one sample t -test

Compares the mean of sample group to set mean ( 7 yr olds vs. Everyone else)
Formula: t = (m-u)/s/sqr(n)
- t = t-value
- m = mean of sample
- u = population mean (theoretical value)
- s = std dev
- n = sample size

Degrees of freedom

N - 1

If t-value < critical value

Fail to reject null hypothesis

If t-value > critical value

Reject null hypothesis

Independent two sample T-test

Compares the mean of 2 different samples, not to theoretical or population mean (boys vs. Girls)
Formula: t = (mA = mB) / sqrt ((sA^2/nA) + (sB^2 / nB))
- mA = mean of A
= mB = mean of B
- sA^2 - variance of A
- sB^2 - variance of B
- nA = sample size of A
- nB = sample size of B

Paired T-test

Compares the mean of sample group to the mean of the same sample group at a different time point (before vs. After)
Formula: t = m / s / (sqrt n)
- m - mean difference between the 2 means
- s = standard dev of difference between 2 means
- n = sample size

More neural connection

= more firing (AP) = faster AP

Histology

Study of healthy tissue

Pathology

Study of unhealthy tissue

Major tissue components

Cells, fibers, matrix (ground substance)

Tissue

Group of cells that act together to perform a specific function

4 basic tissues in human body

- epithelial
- connective
- muscle
- nervous

Epithelial tissue

Tissue that covers and lines organs and organisms
Found on the surface

Connective tissue

Tissue that supports and connects
Not found on the surface

Muscle tissue

Tissue that contracts and produces motion and/or locomotion

Nervous tissue

Tissue that responds to stimuli and conducts impulses for communication of information

Classification of Epithelium

Number of layers
- simple = single layer
- stratified = multiple layers

Shape
- squamous
- cuboidal
- columnar

Function
- transitional
- germinal

transitional epithelium

1. multiple layers of cells
2. superficial layer of cells (dome cells) have shape varying from rounded to flattened depending on distension of organ
3. capacity to stretch

germinal epithelium

found lining the reproductive organs, andthese cells are specialized to produce gametes, the eggs and the sperm

Squaomous

covered with scales or cells

examples of simple epithelium

squamous
- endothelium
- bowmans capsule
- loop of henle
-alveoli

cuboidal
- glands
- ovary surface

columnar (things that need lining?)
- stomach
- kidney tubules
- bronchi
- uterus
- bronchi

examples of stratified epithelium

squamous
- epidermis of skin

cuboidal
- skin
- ducts of sweat glands
term-105
columnar
- large ducts of glands

Specializations of epithelial membranes

- simple and branched glands
- microvilli
- cilia