pressure gradients, blood flow and peripheral resistance

Question 1

pulse pressure calculation

Answer 1

subtract your systolic blood pressure (top number) from your diastolic blood pressure (bottom number)

Question 2

mean arterial pressure equation

Answer 2

DP + 1/3(SP – DP) or MAP = DP + 1/3(PP)

Question 3

why is diastolic pressure not 0

Answer 3

because there will still be some pressure and blood flow to the arteries

Question 4

why are arterioles the major resistance vessels

Answer 4

because they are rigid than larger arteries

Question 5

which nerve innervates the smooth muscle found in the walls of the arterioles

Answer 5

sympathetic nervous system

Question 6

vascular tone definition and 2 factors that contribute to this

Answer 6

the contractile activity of vascular smooth muscle cells in the walls of small arteries and arterioles

Question 7

explain arteries

Answer 7

Low-resistance vessels conducting blood to the various organs with little loss in pressure.
Act as pressure reservoirs for maintaining blood flow between ventricular contractions

Question 8

explain arterioles

Answer 8

Major sites of resistance to blood flow.

Responsible for the pattern of blood flow distribution.

Participate in the regulation of arterial blood pressure.

Question 9

explain capillaries

Answer 9

site of exchange between blood and tissues

Question 10

explain veins

Answer 10

low resistance vessels for the blood to flow back to the heart

their capacity for blood is adjusted to facilitate flow

Question 11

what is the units of flow per unit of time

Answer 11

usually I/min or ml/min

Question 12

what is the units of pressure difference (change in pressure) driving the flow

Answer 12

mmHg

Question 13

explain resistance

Answer 13

A measure of how difficult it is for blood to flow between two points at any given pressure difference.
In other words, a measure of the friction impeding flow

Question 14

explain F=DP/R

Answer 14

F= flow rate of blood through a vessel (I/min)
P= pressure gradient (mmHg)
R = resistance of blood vessels (mmHg.min/I)

Question 15

what are the three factors affecting resistance to blood flow

Answer 15

Viscosity of the blood
Vessel length
Vessel radius

Question 16

what is the major determinant of resistance

Answer 16

vessel radius, a slight change in radius brings about a notable change in flow

Question 17

what is the flow rate equation?

Answer 17

pi x change in pressure x radius(4) /
8 x n (viscosity) x l (length of vessel)

Question 18

what does high arteriolar pressure resistance cause

Answer 18

a marked drop in mean pressure as blood flows through arterioles.
This is physiologically important because this pressure helps drive blood from the heart to the tissue capillary bed.

Question 19

contraction=?

Answer 19

decreased radius, increased resistance = decreased local blood flow = vasoconstriction

Question 20

relaxation=?

Answer 20

increased radius = decreased resistance = increased blood flow = vasodilation

Question 21

what are the 2 factors responsible for vascular tone

Answer 21

myogenic activity
sympathetic activity

Question 22

why is vascular tone important

Answer 22

tonic activity makes it possible to either decrease of increase contractile activity.