Homeostasis and Blood pressure

Blood flow after the heart

elastic artery, muscular artery, arterioles, capillaries, venules, veins.

The structure of blood vessels

tunica externa, tunica media, tunica intima

what is the difference between venules and arterioles

venules just have tunica externa and endothelium, and arterioles just have tunica media and endothelium

what is the difference between elastic and muscular arteries

elastic arteries have a larger endothelium, while muscular arteries have a larger tunica media

tunica media

The middle and thickest layer of vessels, smooth muscle, allows the vessel to expand or contract in response to changes in blood pressure and tissue demand.

blood pressure in the veins

-Blood is at very low pressure.

-Blood is very far from the pumping effect of the heart.

where is blood velocity the lowest

capillaries

what is unique about the capillaries

Have large cross-sectional area, hence the low blood velocity

what is vascular resistance

the opposition to blood flow due to friction between blood and the walls of blood vessels

how is vascular resistance related to blood pressure

the higher the resistance, the higher the blood pressure

vascular resistance formula

8Ln/pi r^4

How can blood viscosity increase

dehydration, blood doping with erythropoietin

what can cause vasoconstriction

Sympathetic NS, angiotensin-renin system

what can cause vasodilation

Parasympathetic NS, nitric oxide

starling forces

a sum of the forces generated by hydrostatic and osmotic pressures; results in a greater attraction of fluid to one side of a membrane

net filtration pressure formula

[Pcap - Pif] - [Ocap - Oif]

what is the net filtration pressure on the arterial side

35mmHg - 26mmHg = 10mmHg

what is the net filtration pressure on the venous side

17mmHg - 26mmHg = -8mmHg

how do you take blood pressure

the first sound is the systolic pressure number when you first hear the Korotkoff sounds, then the number when no sounds are heard is the diastolic pressure

pulse pressure

difference between systolic and diastolic pressure

Mean Arterial Pressure (MAP)

pressure forcing blood into tissues, indicated tissue perfusion

formula for mean arterial pressure

(2 x diastolic) + systolic/ 3

what does pulse pressure indicate

reflecting stroke volume.

cardiac ouput

the volume of blood leaving the heart per min, average is 5Lin a normal resting adult

stroke volume

the volume of blood pumped out by a ventricle with each heartbeat

heart rate

Number of heartbeats per minute.

Cardiac Ouput equation

CO = stroke volume x heart rate

healthy blood pressure

120/80

elevated blood pressure

120-129/less than 80

stage 1 hypertension

130-139/80-89

Stage 2 hypertension

140+/90+

hypertensive crisis

>180 and/or >120

normotension for mean arterial pressure

less 90

elevated MAP

90 - <92

stage 1 hypertension MAP

92-96

Stage 2 hypertension MAP

96+

what is the blood pressure from the aorta to the arterioles

120 > 110 > 40 > 30

Importance of MAP

must be at least 60 to maintain adequate blood flow through coronary arteries, kidneys, and brain

what is the blood pressure in the systemic circulation normally

110

what is the blood pressure in the venous circulation

18-7

Poiseuille's equation

Q = ΔPpir4/8Ln

laminar flow

a smooth pattern of flow

what happens with posture

heart rate increases, SV volume decreases; all due to blood pooling in te legs when we stand.

Homeostasis

Any self-regulating process by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival.

what is a set point

the physiological value around which the normal range fluctuates

what is dynamic constancy

correction in opposite directions of deviation to move it back to a set point, which is continuously happening in fine adjustments

what is the pathway through which homeostasis is maintained

a change is detected by a receptor, then that input is integrated in the control center through afferent nerves, then an output response is sent to an effector, and then this response opposes the change

how is homeostasis maintained

thorugh negative feedback corrective mechanisms

how are posture changes detected

through central and peripheral baroreceptors

how is blood pressure and mean arterial pressure regulated

if mean arterial pressure goes up, the baroreceptors detect that and send it to the vasomotor centre, which activates the parasympathetic system and causes bradycardia and vasodilation

what is pulse oximetry

measurement of oxygen saturation in the blood and pulse rate

what are the characteristics of hemoglobin

composed of four polypeptide chains

each rbc contains 300 million hemoglobin molecules

can bind 4 oxygen molecules

each RBC can transport 1.2 billion oxygen molecules

normal SPO2 levels

greater than 95%

normal SPO2% for people with COPD

88% to 92%

hypoxic SPO2% levels

85% - 94%

severly hypoxic SPO2%

less than 85% in which supplemental oxygen needs to be administered immediately

high pulse rate for females and males

greater than 83

excellent pulse rate for males 20 - 39

58

excellent pulse rate for females 20 - 39

62 - 64

good pulse rate for females 20 - 39

63 - 66

good pulse rate for males 20 - 39

59 - 63

normal pulse rate for females 20 - 39

76 - 82

normal pulse rate for males 20 - 39

71 - 81