Topic 9 - Regulation of blood pressure Flashcards
(11 cards)
1
Q
What is blood pressure?
A
Is the pressure exerted by the blood on the walls of the blood vessels, usually referring to the pressure in the large arteries
2
Q
What are the pressures in the arteries expressed as?
A
- Systolic arterial pressure (during cardia ejection)
- Diastolic arterial pressure (during relaxation)
3
Q
What is the av. person’s BP?
A
120 / 80 mmHg
4
Q
What is the equation involving the mean arterial pressure (MAP)?
A
MAP = cardiac output x total peripheral resistance
5
Q
What is total peripheral resistance?
A
the amount of force affecting resistance to blood flow throughout circulatory system
6
Q
What is the equation involving flow?
A
Flow = pressure change / resistance
7
Q
What is the Baroreceptor reflex?
A
- It is short term blood pressure control mechanism
- It connects together baroreceptors (sensory pressure receptors) in arteries (they detect blood pressure.
- Baroreceptors bring info. to medulla oblongata to state current blood pressure (in card. control area)
8
Q
What is a SET POINT?
A
- Each ind. medulla oblongata has a set pt. = desired BP AT REST.
- Actions are taken to bring BP back to desired BP at rest for ind.
9
Q
How does body decrease BP in the short term?
A
- Increase AP frequency in parasympathetic nerves -> decrease HR
- Decrease AP frequency in sympathetic nerves -> decrease HR & decrease vasoconstriction cause by activated adrenoreceptors in GI tract
10
Q
How does the body control BP (long-term)
A
- Renin-angiotensin system
- Involves renin = hormone
- kidneys secrete renin when low BP as low arteriolar pressure detected by kidney’s/control centre detects its low -> sympathetic nerves to kidney for activation
11
Q
What does renin do?
A
- Renin causes fluid retention & vasoconstriction, increasing BP
- Occurs by convert inactive angiotensinogen -> angiotensin I. Then it goes from I to II.
- The angiotensin II acts on AT1 receptors, resulting in the effects.
*Note: renin is also an enzyme
