quizlet import

what does cardiovascular system play a large role in

exercise and performance

functions of cardiovascular system

delivery of oxygen and other nutrients, removal of CO2 and other waste products, transportation of hormones, maintenance of homeostasis, and prevention

heart

serves as the pump

vasculature

serve as channels for transport

blood

fluid which circulates throughout the body and serves for trasnportation

myocardium

cardiac muscle, highly aerobic, large number of mitochondria, and contain more type 1 fibers

desmosomes

hold cells together

gap junctions

intercalated discs

myocardium looks like:

shorter than skeletal muscle fibers, striated, branched

how does the heart contract

uses a cardiac conduction system to signal contraction

autoconduction

spontaneously generates its own electrical signal to contract

AV node bpm

40-60

ventricular cells bpm

20-40

cardiac conduction system

AP originates in sinoatrial node and travels the atrium to atrioventricular node, AP passes through AV node, AV bundle divides into the left and right branches and AP descend to apex of the ventricles, and the AP is carried by purkinje fibers from the bundle branches to ventricular walls

cardiac cycle

all the events between two consecutive heart beats

systole

contraction period of the heart

diastole

relaxation period of the heart that allows the chambers to fill with blood

what is 2/3 of the time spent in heart beat

diastole

most prominent factors that influence HR

parasympathetic and sympathetic nervous systems

vagus nerve

parasympathetic fibers innervate the heart through this cranial nerve

hyperpolarization

moving the resting membrane potential further away from threshold

vagal tone

The constant inhibition provided to the heart by the vagus nerve. Vagal tone reduces the intrinsic firing rate of the SA node from 120 beats/minute to around 80 beats/minute.

arteries

carry blood away from the heart to the arterioles

arterioles

smaller branches of arteries that surround the smooth muscle which lets blood pass through to capillaries

capillaries

exchange between tissues and the blood

venules

blood passes from capillaries to venules

becoming veins

venules that have increased in size when they move back to the heart

veins

carry blood towards the heart and contain valves that prevent back flow

what is blood

third component of the cardiovascular system

function of blood

transport gas, nutrients, and waste, regulate temp, buffer and locate acidity, helps maintain proper pH

blood volume

related to body size and state of aerobic training; 5-6 L in men and 4-5 L in women

composition of blood

total blood volume is composed of plasma and formed elements

plasma

mostly water and dissolved ions, proteins, and hormones

hematocrit

total blood volume red cells, white cells, and platelets

red blood cells name

erthrocytes

red blood cells

constantly destroying and producing new cells; transport oxygen

cell component

red and white blood cells and platelets

polycythemia

excess production of red blood cells causing an abnormal increase in red blood cells

anemia

abnormally low red blood cell count

liquid component

water, clotting proteins, transport proteins, lipoproteins, glucose, fatty acids, antibodies, tranferrin, waste products, etc.

plasma

the liquid component of blood and all its non-cellular content

serum

what remains of plasma after blood has clotted

where is blood sent in the body

metabolically active tissues get the most amount

what happens to blood with exercise

blood goes to the muscles,

vasodilation

increase in artery diameter

vasconstriction

decrease in artery diameter

control of blood distribution

done by arterioles

autoregulation

local control of blood distribution

extrinsic neural control

nervous system input controls blood distribution; smooth muscles has receptors that control dilation and constriction

stroke volume

volume of blood pumped from the left ventricle during each contration of the heart

end diastolic volume

volume of blood in the left ventricle at the end of diastole

end systolic volume

volume of blood remaining in the left ventricle at te end of systole

SV formula

EDV-ESV

cardiac output

volume of blood pumped by the left ventricle per min

Q=

Heart rate times stroke volume

Q=

beats/min times ml/beat=ml/min

breathing

pressure changes aid in the return of blood

muscle pump

contractions squeeze veins and force blood back toward the heart

valves

located in veins and allow for flow only toward the heart

Frank-Starling Law of the Heart

increase in EDV results in a lengthening of cardiac fibers, which improved the force of contraction in a manner similar to skeletal muscle, an increase in length of cardiac fibers increase the number of myosin cross-bridge interactions with actin, increase number of cross bridges increases the force production, rise in contractility leads to an increased amount of blood pumped each beat

artic pressure (afterload)

represents a barrier to the ejection of blood from the ventricles

preload

volume of blood in ventricles at the end of diastole

afterload

resistance left ventricle must overcome to circulate blood

blood pressure

the pressure exerted by the blood against the vessel wall

systolic blood pressure

highest blood pressure that occurs during contraction of the heart

diastolic blood pressure

lowest pressure that occurs during the filling of the heart

mean arterial pressure

average pressure exerted by the blood as it travels through arteries

MAP formula

DBP + 1/3 (SBP-DBP)

control of blood pressure

blood vessel constriction increases blood pressure, dilatation reduces blood pressure

hypertension

high blood pressure; increases the workload on the left ventricle

left ventricular hypertrophy

thickening of the left ventricle

systolic pressure

greatest pressure during contraction

normal systolic pressure range

100-140 mmHg

diastolic pressure

lowest pressure during the filling stage

normal diastolic pressure

70-90 mmHg

max systolic pressure

250 mmHg

max diastolic pressure

120 mmHg

low systolic pressure

70 mmHg

Hypertension

more than 140 systolic and more than 9 diastolic

hypotension

less than 100 systolic and less than 70 diastolic

hypertension outcomes

headache, fatigue, confusion, vision problems, chest pain, difficulty breathing, irregular heartbeat, blood in urine, pounding in chest, neck, or ears

factors that increase BP

obesity, insulin resistance, high alcohol intake, high salt intake, aging, sedentary lifestyle, stress, low potassium intake, low calcium intake

BP=

CO times R or Q times R

blood flow

difference in pressure/resistance

resistance

length of vessel times viscosity of fluid/radius4

how can blood flow be increased

an increase in blood pressure or decrease in resistance

what changes due to acute exercise

heart rate, stroke volume, and cardiac output increase, blood distribution changes

why are the changes due to acute exercise important

meet increased metabolic rate, help regulate temp, and provide more oxygen, nutrients, and remove waste

normal resting heart rate

60-80 bpm

exercise heart rate

heart rate will increase due to intensity of the exercise

max heart rate

highest value achieved in an all out effort

age predicted max heart rate

220-age

target heart rate

intensity (220-age)

stroke volume and exercise

increases with exercise up to 40% to 60% of max

factors that increase stroke volume with exercise

volume of returning venous blood, ventricle size, ventricle contractility, and total peripheral resistance

exercise and cardiac output

cardiac output determines the amount of blood presented to working muscles

cardiovascular drift

A gradual time-dependent downward "drift" in several cardiovascular responses, most notably stroke volume with a compensatory heart rate increase, during prolonged steady-rate exercise

blood plasma volume and exercise

reduces with onset of exercise (fluid moves to interstitial space)

endurance exercise

systolic BP increases in direct response to increases in intensity; diastolic BP changes very little

arterial venous oxygen difference

amount of oxygen extracted from the blood as it travels through the capillaries