Lesson 19: Blood Pressure and Capillary Dynamics Flashcards
(20 cards)
What is the difference between systolic and diastolic pressure?
Systolic Pressure: Pressure exerted on artery during ventricular contraction.
Diastolic Pressure: Pressure exerted on artery during ventricular relaxation.
What is pulse pressure?
Difference between the systolic and diastolic pressures.
What is mean arterial pressure?
The average pressure in a patient’s arteries during one cardiac cycle. (MAP = Diastolic Pressure + Pulse pressure/3)
Min 60mmHG needed to have enough oxygen for vital organs.
What is capillary blood pressure?
Blood entering the capillaries has a pressure of around 35mmHg. Blood drops to around 17mmHg by the time it exits.
What is venous blood pressure?
Steady blood pressure occurs here. Continues to decrease from 17mmHg in venules to almost zero in the vena cava.
What are the three factors that influence blood pressure?
- Cardiac output (CO)
- Peripheral resistance (PR)
- Blood volume
What are the two factors that alter peripheral resistance?
- Vascular tone
- Blood viscosity
Which organs regulates the blood volume?
the kidneys
What are baroreceptors, chemoreceptors and proprioceptors?
Baroreceptors: Detect changes in blood pressure
Chemoreceptor: Detect changes in blood pH, CO2 and O2.
Proprioceptor: Detect increased body movement.
What are the two baroreceptor reflexes and their function?
Carotid Sinus reflex: Ensures blood flow to the brain. Sensory input via the glossopharyngeal nerves.
Aortic reflex: Helps maintain systemic blood pressure as a whole. Sensory input via the Vagus nerve.
(Respond to stretching of blood vessel walls).
What causes the stimulation of cardio acceleratory and cardioinhibitory center?
Cardio acceleratory: Low BP, low pH, low O2 and high CO2.
Cardio inhibitory: High BP, high pH and low CO2.
What is the vasomotor center?
Alters peripheral resistance through vasoconstriction of blood vessels.
What does the vasomotor center do when BP is too high vs. too low?
BP High: Vasomotor receives inhibitory impulses from baroreceptors. This causes sympathetic motor output being inhibited and vasodilation.
BP low: Vasomotor doesn’t receive impulses from baroreceptors. Chemoreceptors help with vasoconstriction and sympathetic motor output is stimulated.
What is Renin - Angiotensin - Aldosterone System?
- When blood pressure drops, kidneys release an enzyme called renin into the blood stream.
- Renin splits angiotensinogen into angiotensin I.
- Angiotensin I is converted to Angiotensin II by Angiotensin converting enzyme.
- Angiotensin II helps with secreting Aldosterone, ani diuretic hormone, makes us feel thirsty and causes vasoconstriction.
What is hypertension and how can it be treated?
Hypertension is elevated level of blood pressure and can be avoided by healthier diet/lifestyle, antihypertensive medications.
Such medications decrease BP by reducing cardiac output, peripheral resistance or blood volume.
What is hydrostatic pressure?
Force exerted by a fluid against a vessel wall and is equal to blood pressure. Forces fluid out of the capillary at the beginning (arteriole end). Filtration
35 - 17mmHg
What is colloid osmotic pressure?
Force pulling water back into the blood sue to many large non penetrating solutes (plasma proteins). Relatively constant pressure
What happens at the arterial and venous end?
Arterial end: Filtration since hydrostatic pressure is greater than colloid osmotic pressure.
Venous end: Reabsorption since hydrostatic pressure less that blood colloid osmotic pressure.
What is edema?
An abnormal increase in the amount of interstitial fluid within tissues.
What are some causes of edema?
- Increased capillary hydrostatic pressure causes more filtration.
- Increased blood vessel wall permeability
- Increased OP (if) and decreased OP (c).
Blocked lymph vessel preventing fluid drainage.
