4434 Midterm

Aging

The process of becoming older

Senescence

The decline of biological functions that occur with advanced age

Oldest person ever

Jeanne Louise Calmenet

aged 122

Oldest person alive

Kane Tanaka

Aged 119

Chronological Age

exact age from birth. cannot be modified

Biological Age

Age determined by physiology. can be modified

Functional Age

age in terms of functional performance. dependent on biological and chronological age. can be modified

"I am 22 years old"

Chronological Age

Mom who is 64 but has the organ health of someone who is 50

biological age

Someone who is 65 years old and has the similar grip strength of someone who is 40

functional age

Life expectancy in Canada

82 years

Male life expectancy in Canada

80 years

Female life expectancy in Canada

84 years

Increases in life expectancy are mostly due to

modern medicine, technology improvements, nutrition, clean water, decrease in smoking trends, indoor plumbing, education

Start of the field of gerontology

1940s

Psychosocial theories of Aging

activity theory, continuity theory, disengagement theory

Biological theories of Aging

Programmed longevity theory, Immunological theory, Endocrine theory, Wear and tear theory

Programmed Longevity Theory

theory that aging is genetically programmed

* genes programmed to shut off at certain time

Programmed Longevity theory: Hayflick's Limit

telomeres shortening which damages the DNA and there is no further division

specific to cells that continue to divide (skin, endothelial)

Telomerase

enzyme that helps replace DNA and replenish lost telomere due to aging, maintains the length of the telomere

"Dramatic rejuvenation of prematurely aged mice hints at potential therapy"

Telomerase was used to try and reverse the aging process and was successful

Immunological Theory

Aging is largely controlled by the immune system. It is a mild, prolonged auto-immune disorder

"Inflamm-aging"

Immunological theory

Elements of the Non-Specific Immune System

Barriers and phagocytes

Examples of barriers for the immune system

skin and mucus

Elements of the Specific Immune System

B-Cells and T-Cells

what are Barriers

Part of the non specific immune system that prevents pathogens and foreign bodies from entering the body

what are Phagocytes

part of the non-specific immune system that binds to pathogens in a non-specific way, takes it in as a phagocyte and destroys it

what does the Non-Specific Immune system do

responds to non-specific pathogens in the body. adaptive immune system

what does the Specific Immune System do

responding to specific pathogens

what are B-Cells and where are they produced

produced in the bone marrow. responsible for attacking pathogens that are not in a cell

ex: in the blood or plasma

what are T-Cells and where are they produced

produced in the thymus. will attack pathogens that are engulfed inside of cells

Differences b/w B and T cells

* B cells act outside the cell, T cells act inside the cell
* where they are produced

Major trigger to immune system activation

Inflammation

Ways to decrease inflammation

healthy diet and exercise
sufficient sleep
anti-inflammatory drugs

Endocrine Theory of Aging

Changes in the endocrine control of homeostasis result in age-related changes in physiology

What happens to the hypothalamus as a result of aging

Smaller hypothalamus, increased calcification, hormone imbalance

Potential intervention for hypothalamus cell decline

increased number of hypothalamic cells in older mice showed similar function to young control

Wear and Tear Theory

progressive damage to cells and tissues over time

Free Radical Theory

Wear and Tear theory - accumulation of a particular stress over time causes increase free radicals

Free Radical

atom with an uneven number of electrons - unpaired and unstable election

Reactive Oxygen Species (ROS)

free radicals that contain oxygen (Nitric Oxide, Superoxide)

Where do we get ROS from?

Electrons escaping the ETC that react with oxygen

Functions of ROS

cell differentiation, autophagy, immune system functions

relationship b/w oxidative stress and ROS

too much ROS and not enough antioxidants to stabilize them

consequence of having a large level of ROS

DNA Fragmentation

Other causes of ROS

UV rays, pollution, chronic inflammation, smoking, obesity, radiation, metabolism

Ways to reduce ROS

healthy diet and exercise
caloric restriction

Components of the Cardiovascular system

heart, blood vessels, blood, nervous system

Functions of the Cardiovascular System

transportation, maintain temperature, protect from infection, distribute hormones

causes of Decreases valve function

repeated mechanical stress, infection/inflammation, genetics

causes of Death of Pacemaker cells

ROS, infection/inflammation/genetics

Causes of thickening of LV wall

hypertrophy of remaining cells that are working harder to generate the same force

cause Atheroscleroris

Condition characterized by deposits of fat, lipids, cholesterol in the arteries that limits the amount of space for the blood to flow

cause of Arteriosclerosis

Condition that resutls in the thickening/hardening/stiffening of the artery walls

function of Sympathetic Nervous System (SNS)

Fight or flight

function of Parasympathetic Nervous System (PSNS)

Rest and digest

what are Baroreceptors, what are their function, what happens with age

mechanical receptors that are within the aorta and carotid sinus that detect changes in blood pressure/volume within the arteries. less responsive with age

Short term cardiovascular response to exercise

increased heart rate, stroke volume, blood pressure

Long term cardiovascular responses to exercise

decreased heart rate, blood pressure, cholesterol, risk of diabetes
increased SV, exercise capacity, longevity, function

what is the Pressor Response to Exercise

increases sympathetic activity to the heart and systemic vessels and decreases parasympathetic activity to the heart, which increases BP, HR and total peripheral resistance through vasoconstriction of systemic vessels

Changes in the function of heart with age

increased BP, arrhythmia, orthostatic hypotension
decreased contractile force, cardiac output, blood flow, response to baroreceptors, response to exercise

Skeletal System Function

support structure, allow movement, makes blood cells, protection or organs, stores minerals

what are Trabecular Bones

where bone marrow is

What bones are composed of

minerals (phosphorous, calcium) and collagen

Osteoblasts

cells that form new bones

Osteoclasts

cells that dissolve bone (resorption)

Osteocytes

mechanosensors that help signal bone remodelling. sense stresses and strains on the bone and signal the osteoblasts and osteoclasts accordingly

Changes in bone structure with age

decreased osteoblasts in the marrow, decreased calcium and vitamin D, hormonal imbalance inflammation

Age related skeletal disorders

osteoporosis, arthritis

Osteoporosis

porous bone - reduction in bone mass that becomes clinically significant
deterioration of bone tissue and mass.

Osteopenia

bone loss that is not as a serious as osteoporosis.

Dowager's Hump

spine hump that is classic to osteoporosis

is PA in general and strength training safe for older adults with osteoporosis?

Yes

are strength training and physical activity beneficial for maintaining bone density?

Yes

what is Arthritis in general

inflammation of joints

Osteoarthritis

degeneration of cartilage exposing bone surface from long-term use. Wear and tear theory

Rheumatoid Arthritis

auto-immune disease that attacks synovial membrane and replaces it with a grainy fluid in the joints that exposes the cartilage. immunological theory

effects of PA in patients with arthritis

pain reduction, psychological benefits, better blood flow, better quality of life

Sarcopenia

age related decline in muscle mass and strength

"Old" in athletics

30 because of the start of the physiological decline of our bodies

Motor unit (MU)

smallest functional unit of a muscle. consists of a single Motor neuron and all the muscle fibres it inner ages

Summation of Twitches

complete tetanus

Muscle fiber recruitment with age

the number of motor units that decreases changes depending on the muscle and what the muscle is used for.

Ex: fewer decreases in the calf muscles vs the biceps

use it or lose it

Why do we lose motor neurons?

increased inflammation + ROS, decreased astrocyte function, type of activity (Type I vs II)

What happens to orphaned muscle fibres?

they die or they are re-innervated

Motor neuron Death

motor neurons are lost first. We end up with muscle fibres that have no neural innervation

Type I muscle fibres

low intensity. aerobic.

Type II muscle fibers

fast twitch, high intensity.

How do we maintain MU's?

keep using them

Lose more of these kinds of muscle fibers with age

Type II

How are type II fibres lost with age

type II generally die off and are re-innervated by type I motor neurons nearby therefore giving them type I properties

Branching + Reinnervation of muscle fibers

Typically take on Type I characteristics, larger twitch force every time the MU is activated

what happens to Rate Coding with age

declines with advanced age.

what happens to motor unit Recruitment with age

fewer motor units, fewer force per unit

oxidative phosphorylation in older individuals

the proportion of ATP being generated through the oxidative proportions of greater in older individuals muscle fibres due to increased type II fibres

what is Functional Capacity

our abilities to complete ADL's

what is Functional Reserve

difference between your functional capacity and the disability threshold

what is Disability Threshold

point at which functional capacity falls below what is needed

Biggest predictor of older adults functional capacity

muscle power