Blood Vessel Physiology Flashcards
What is blood pressure?
Blood pressure is the measure of force blood exerts against blood vessel walls.
Systolic pressure
-When ventricles contract and blood is pushed into the blood vessels
- Maximum pressure
Diastolic pressure
- When the ventricles relax and blood stills
- Minimum pressure
what is a normal blood pressure
120/80
know how to measure blood pressure
what is the first number on bp?
systolic
what is the second number on bp?
diastolic
where can Pulse pressure points be felt?
near large arteries
what is pulse pressure?
the difference between systolic and diastolic blood pressures
how do you find pulse pressure?
120 for systolic / 80 for diastolic;
pulse pressure is 40 mm Hg
Capillary Exchange
-Fluid can pass through capillary walls – not only oxygen and CO2
- Fluid will pass from blood into the tissues
- Blood pressure, capillary permeability and osmosis affect movement of fluids across capillary walls.
- Fluid gained in tissues is removed by lymphatic system
Blood Flow Control Mechanisms
- Local- Periarterial sphincters
- Nervous - Reflexes – respond to changes in blood pressure and blood chemistry
- Hormonal
- Epinephrine/Norepinephrine
- Renin-Angiotensin-Aldosterone Mechanism
- Antidiuretic Hormone (ADH)
- Long Term Changes
Mean Arterial Pressure
-is a calculated value that reflects an average arterial pressure in various vessels of the body.
- The body’s MAP is equal to the cardiac output (CO) times the peripheral resistance (PR).
what is the MAP equation?
MAP = CO × PR
Cardiac output and Peripheral resistance meaning
-Cardiac output is equal to the heart rate (HR) times the stroke volume (SV).
- Peripheral resistance is the resistance to blood flow in all the blood vessels.
how is local control achieved?
relaxation and contraction of precapillary sphincters
local control controls what?
controls how much blood gets into the tissues
Cardioregulatory control center
controls the heart
Vasomotor Control Centers
controls blood vessel diameter and tone
Vasomotor Tone
- State of partial constriction of blood vessels
- Increase causes blood vessels to constrict too much and blood pressure
to go up
Baroreceptors reflexes
-help keep blood pressure in normal range
-Cause a change in peripheral resistance, heart rate, or stroke volume in response to blood pressure
As blood pressure increases what happens?
- Barorecptros detect increase
- Vasomotor center slows sympathetic stimulation
- Heart rate, stroke volume decrease
- Blood vessels dilate
- BP lowers
As blood pressure decreases what happens?
- Baroreceptors detect decrease
- Vasomotor center increases sympathetic stimulations
- Heart Rate, Stroke volume increase
- Blood Vessels constrict
- BP increase
Chemoreceptors
- Monitor blood chemistry
- Oxygen, Carbon Dioxide and pH
- Specialized cells in carotid bodies
and aortic bodies inside the carotid
sinuses and aortic arch - Send signals to the to cardioregulatory center in the medulla oblongata
3 steps for Adrenal Medullary Response
- Stimuli increase sympathetic stimulation to adrenal medulla
- Adrenal medulla secretes epinephrine and norepinephrine into blood
- This causes increased heart rate and
stroke volume and vasoconstriction
Antidiuretic Hormone (ADH)
- Nerve cells in hypothalamus release
antidiuretic hormone (ADH) when
concentration of solutes in plasma
increases or blood pressure decreases - ADH acts on kidneys and they absorb more water (decrease urine volume)
- Result is to maintain blood volume and blood pressure
Arteriosclerosis
- Hardening of the arteries
- Makes arteries less elastic and more resistant to blood flow
Atherosclerosis
- type of arteriosclerosis
- from deposit of materials in artery walls (plaque)
Factors that contribute to atherosclerosis
lack of exercise, smoking, obesity, diet high in cholesterol and trans fats
