A L1.2 variation in BP Flashcards
1
Q
Blood pressure equation
A
- BP = DBP + 1/3 (Pulse Pressure)
2
Q
How is population variation of BP modelled?
A
- Population of BP is unimodal
3
Q
High blood pressure predisposes:
A
- Coronary heart disease
- Stroke (Could cause a hemorrhage in the brain, ↑ level of stress by ↑ BP)
- Cardiac hypertrophy (↑size as a result of facing ↑demands)
- Heart failure
- Kidney failure
- Kidneys receive 25% of cardiac output
- ↑BP → ↑ glomerular pressure → damage glomerular capillaries → kidney failure
- Blindness from diabetes (accentuated by ↑ in BP)
4
Q
3 ways of variation within a population
A
Sex, Age, Body Size
5
Q
Within population: Sex
A
- Males > Females BP (Men generally weigh more - relates to body size)
6
Q
Within population: Age
A
- BP rises with age
- ~60 mmHg at birth, ~120mmHg at adulthood
- But DBP falls after 60yo, as a result of ↓compliance of arteries (arteries hardening)
- Results in ↑ in pulse pressure with age
- Females > Males during puberty (earlier puberty for girls)
7
Q
Within population: Size
A
- ↑BMI → ↑BP
- E.g.:
- Tracking BP from birth:
- If you have a higher BP, there is a tendency to have a higher BP at adulthood
- BUT BP during puberty fluctuates (Height plays an important factor)
- If you have a higher BP, there is a tendency to have a higher BP at adulthood
- Westernised vs ‘unacculturated’ (hunting for own food)
- BP increases with age for westernised, but stay generally constant with ‘unacculturated’
- Constant physical activity for unacculturated → ↓mean body size → ↓BP
- Tracking BP from birth:
8
Q
Variations within inidividuals: diurnal
A
- High variations/fluctuations of BP during the day
- Often associated with stress & Strain, ↑ up to 200mmHg
- Low variation during night
- Sympathetic activity is dulled, ~20mmHg less than day
9
Q
Variations within individual: seasonal
A
- Summer < Winter (~3mmHg)
- ↑Temp
- ↓TPR
- ↑Sweat → ↓ECF → ↓V.R → ↓SV → ↓CO
- ↑Temp
- Different diets during summer
10
Q
Relationship b/w Na reabsorption & H+
A
↑Na reabsorption → ↑H+ lost
