8: Hypertension and the Kidney Flashcards
(15 cards)
What is blood pressure?
The force exerted by blood against the walls of the arteries as the heart pumps it around the body
What is normal blood pressure?
120/80mmHg
How is blood pressure recorded?
As two values:
Systolic blood pressure (blood pressure during contraction)
Diastolic blood pressure (blood pressure at rest)
What is hypertension?
Sustained/chronic elevation in blood pressure
Major modifiable risk factor for stroke, vision loss, heart attack, sexual dysfunction, kidney failure, cognitive decline, and dementia
What blood pressure readings would constitute hypertension?
Systolic > 140mmHg
Diastolic > 90mmHg
What are the two key equations for this topic?
Blood pressure = cardiac output x total peripheral resistance
Cardiac output = stroke volume x heart rate
(total peripheral resistance = vascular diameter)
What are some risk factors for hypertension?
Blood volume, abnormal arteries, weight, genetics, salt consumption, physical inactivity, alcohol consumption, environmental factors (e.g. geophysical faactors, temperature, air pollution, etc.)
What percentage of the body is made up of water?
In children, 70%
In grown men, 60%
In grown women, 50%
And in older people, 50%
What are the three major fluid compartments in the body?
Plasma (8%)
Intracellular fluid (67%)
Interstitial fluid (25%
Water moves freely between the three compartments
What is plasma?
The liquid part of blood
Makes up a large proportion of its volume
Mostly made of water, proteins, glucose, hormones, waste, etc
What is intracellular fluid?
The fluid inside cells
Makes up about two-thirds of all bodily fluid
Contains water, ions, proteins, and other important molecules
What is interstitial fluid?
Fluid surrounding and bathing cells of tissues Comes from blood plasma and helps to deliver nutrients, oxygen, and remove waste Sits between blood vessels and cells
What is the nephron?
The basic functional unit of the kidney
Filters blood, removes waste and regulates water and electrolyte balance
How does the nephron maintain a balance between water and salt content in the body?
Glomerulus filters the blood to form filtrate
PCT reabsorbs most salts and water
Loop of Henle creates a salt gradient to reabsorb water in the descending limb and then salts in the ascending limb
DCT fine-tunes salt reabsorption, influenced by aldosterone
Collecting duct: reabsorbs water under control of ADH, concentrating urine
Why can having high salt levels lead to hypertension?
High salt levels cause the body to retain more water
Increases blood volume
Raises blood pressure
