Physiology - Death Flashcards Preview

MBBS - Year 1 > Physiology - Death > Flashcards

Flashcards in Physiology - Death Deck (63)
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1
Q

Life span

A

the potential maximum to which a species can live

2
Q

Life expectancy

A

the avg no. years a person may live from a given age

3
Q

Healthy life expectancy

A

Avg no. years a person may live in good health from a given age

4
Q

Why is there a faster increase in life expectancy in males

A

Reduced smoking and improved treatments for cardiovascular disease as well as less hazardous working environments

5
Q

Age-related changes must …

A

Be deleterious
Be progressive
Be intrinsic
Be universal

6
Q

Do we all age at same rate

A

How we live and the environment in which we live can have a dramatic effect on the way in which we age
Sun exposure and smoking speeds age related changes in the skin

7
Q

General changes seen in ageing

A

Loss of height
Loss of fat free and lean body mass
Gain and redistribution of adipose tissue
Grey hair

8
Q

Why do we lose height when ageing

A

Disc degeneration but can be reduced by 50% with exercise

9
Q

What is the effect of losing lean body was

A

Metabolically active so decreases basal metabolic rate and strength

10
Q

Why does hair turn grey

A

Failure of melanocytes

11
Q

Effects of aging on skin

A
Wrinkles 
Blotchiness 
Thinning epidermis 
Slowing of keratinocyte generation 
Loss of elasticity in dermis due to changes in collagen and elastin
Lumps & bumps 
Dry – loss of oil secreting glands
12
Q

Skin pathology when ageing

A

Ulcers

Skin cancers - BCC, SCC

13
Q

Sun damage/ photo-ageing

A

Solar elastosis
Solar lentigines
Melasma
Actiniic keratoses

14
Q

Solar elastosis

A

UV radiation breaks down elastic tissue in skin

15
Q

Solar Lentigines

A

Dark brown spots that appear with age

16
Q

Melasma

A

Dark patches of skin usually on the face and related to female hormones

17
Q

Actinic keratoses

A

Rough scaly area of skin

Precancerous

18
Q

UVB rays and ageing

A

Can cause DNA mutation, directly by creating compounds that affect pyrimidine bases

19
Q

UVA rays and ageing

A

Penetrate dermis and damage leads to smaller dermis and damage to blood vessels
Damage DNA directly through production of Reactive Oxygen Species (ROS)

20
Q

What can lead to free radical generation

A

UV
Infl
Production of cytokines

21
Q

What can cause vitamin A deficiency in the skin

A

UV rays

22
Q

Langerhans cells and ageing

A

Reduce as we ages

23
Q

Langerhans cells and skin infections

A

The local Langerhans cells will take up and process microbial antigens to become fully functional antigen-presenting cells

24
Q

BCC

A

Basal cell carcinomas
Most common in UK
Invasive but rarely metastasizes - related to sun damage
Increases cross-linking

25
Q

SCC

A

Squamous cell carcinomas
Occurs wherever there is squamous epithelium, so cervix usually an SCC
On skin related to sun exposure

26
Q

Seborrheic keratosis

A

Keratocytes in epidermis, etiology unsure

27
Q

Reparing damaged skin

A

Retinoids, related to vit A, can alter structure of skin partly reversing or slowing process of photoaging
CO2 lasers, resurfaces skin by causing collagen production

28
Q

Sarcopenia

A

Loss of skeletal muscle with age due to Inactivity and loss of motor neurons innervation

29
Q

Loss of muscle mass and strength in ageing

A

Reduction in baseline protein production rate

  • Activity related
  • Fat infiltrating muscle plays a role
  • Infl
  • Innervation
  • Multifactorial
30
Q

Ageing and CVD

A

Stiffening due to increased collagen, widening of large arteries
Reduced ability to contract & dilate smaller arteries
Cardiomegaly
Reduced responsiveness to exercise
Postural hypotension

31
Q

Cardiovascular pathology when ageing

A

Arteriosclerosis
Atherosclerosis
Coronary heart disease

32
Q

Arteriosclerosis

A

Hardening of arteries
Thickening of muscle
Calcification
Can be caused by high bp

33
Q

Atherosclerosis

A

Atheroma plaque, cholesterol, and macrophages

34
Q

Ability of aorta to expand under pressure

A

Reduces with age

If aorta cannot stretch, then bp higher as being forced through a non-compliant rigid pipe

35
Q

BP changes with age

A

Mean BP doesn’t change much with age
Systolic pressure increases with age
Reduced aortic compliance

36
Q

Baroreceptor sensitivity in those >75

A

Reduced - reacts to changes in bp so reduces ability to compensate for sudden change in bp

37
Q

Effects of aging on respiratory system

A

Intercostal and diaphragm muscles
Lung tissue becomes less elastic
Reduced ciliary function
Impaired ventilation

38
Q

Respiratory system pathology when ageing

A

Lung cancer

Bronchitis

39
Q

Maximum ventilation volume

A

Maximum amount of air breathed in a minute

40
Q

Maximum O2 uptake

A

Maximum amount of oxygen taken in a minute (exercise)

41
Q

Accumulative lung damage

A

Gradual increase of carbon deposits over time, emphysema

42
Q

Effects of ageing on GI system

A

Reduced absorption of some vitamins D & B12
Reduced mucus secretion – increases risk of trauma and infection
Reduced motility
Reduced hepatocytes
Constipation

43
Q

GI system pathology ehern ageing

A

Diverticulosis
Gallstones
Cancer

44
Q

Effects of ageing of GU system

A
GFR decreases with age 
Adaptability to change slower 
Reduced ability to postpose bladder voiding
Cannot completely void bladder contents 
Prostatic hypertrophy
45
Q

GU pathology when ageing

A

Urinary incontinence
Prostate hyperplasia
Prostatic cancer

46
Q

How does ageing affect drug clearing by kidneys

A

Atherosclerosis and stenosis of renal arteries leads to high bp and reduced GFR by as much as 50% by 80yrs
Excretion of sodium ions and drugs
Drug regimens and timings may need to be altered

47
Q

Presbyopia

A

Age related long sighted, can’t focus on things as close up, may be related to loss of ability to change shape

48
Q

Presbycusis

A

Hardening and narrowing of the blood vessels that supply blood to cochlea —> less blood gets through.

You may also have heart disease, high bp or diabetes

49
Q

Causes of presbycusis

A
Exposure to noise over the years.
Exposure to stress over the years.
Exposure to drugs or chemicals over the years.
Smoking.
Being overweight.
Hereditary
50
Q

30 dB

A

~ sound of quiet whisper

51
Q

60 dB

A

~ sound of normal speech

52
Q

Theories of ageing

A

Gene regulation
Free radical theory
Neuroendocrine

53
Q

Free radicals

A

Any independently existing molecular species that contains an unpaired electron
Many are unstable and highly reactive

54
Q

ROS

A

Atom with unpaired electron so highly reactive

Relates to O2 consumption

55
Q

When are free radicals formed

A

During cellular reactions

56
Q

Protection from ROS

A

Resistance of oxidative stress

  • SIRT1, infl
  • SIRT2 – metabolism
57
Q

ROS and longevity

A

Some evidence that ROS can increase longevity by activation of SIRT3
Complex interaction between ROS and antioxidants that may be dose dependent
Decreased neurodegeneration

58
Q

Gene theory

A

Telomeres shortened with each cell division which leads to cellular damage each time the cell divides
Cells cease replication once telomeres reach a certain length and cell goes into senescence
Telomerase can replace and repair telomeres ends of DNA being recognized as breaks, and triggering repair mechanisms

59
Q

Where is telomerase found

A

Germ and cancer cells

60
Q

What are shorter telomeres associated with

A

Increased disease risk

61
Q

What can rate of telomere shortening be influenced by

A
Age
Smoking 
Exercise
Body weight
Genetics (but not sex)
Stress
62
Q

Homeostatic (neuroendocrine) theory of ageing

A

Hypothalamus becomes less sensitive (no clear mechanism)
Loss of fine hormonal control
Cortisol increases (damages hypothalamus?)
Cortisol role in fat production/storage
Decreases bone formation

63
Q

Health ageing

A
Diet
Sleep
UV exposure
Activity
Smoking
Stress
Fluids

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