PHYSIOEX – Flashcards

Flow= pressure gradient/ resistance

The amount of blood moving through a body area or the entire cardiovascular system in a given amount of time.

TRUE

A measure of the degree to which the blood vessel hinders, or resists, the flow of blood.

Blood vessel radius Blood vessel length Blood viscosity

TRUE, because of the friction dragged between the blood and the vessel walls.

TRUE, lipid deposits can also cause the radius of an artery to decrease, preventing blood from reaching the coronary tissue, which frequently leads to a heart attack.

TRUE

TRUE, because of the friction between the blood and vessel walls. The length of a person's blood vessel changes only as a person grows.

Blood "thickness" determined primarily by hematocrit. The higher the hematocrit, the greater the viscosity.

White blood cells (leukocytes), red blood cells (erythrocytes) and platelets (thrombocytes).

directly proportional

Peripheral resistance

Blood viscosity Blood vessel length Blood vessel radius

Laminar flow

Dehydration Blood cell count (e.g polycythemia)

TRUE, the longer the vessel, the greater the resistance to blood flow through the blood vessels because there is a larger surface are in contact with the blood cells.

TRUE

TRUE

Increases

TRUE, this pressure difference is referred to as a pressure gradient.

TRUE

TRUE, if the heat changes its force of contraction, the blood vessel need to be able to respond to the changes in forces.

70 Heart chambers fill during diastole (relaxation of the heart) and pump blood out during systole (contraction of the heart).

Stroke volume The difference between the end diagnostic volume (EDV) and end systolic volume (ESV).

All fluids move from an area of higher fluid pressure to an area of lower fluid pressure. The blood vessel contract in one area and dilate in another area to direct blood flow.

As the radius increases the flow will also increase. When radius decreases the flow decreases.

Increase blood vessel radius increases the laminar flow. Decrease in blood flow radius decreases the laminar flow.

The increase in blood radius resulted in a corresponding exponential increase in the rate of blood flow. Small increments in the radius resulted in larger increments in flow rate.

Presence of plasma proteins Formed elements (WBC's, RBC's & platelets)

Increase viscosity decrease blood flow because of the blood thickness.

As viscosity increase flow decrease

Polycythemia is a condition in which excess red blood cells are present, and certain types of anemia result in fewer RBC's. Increasing the number of red blood cells increases blood viscosity, and decreasing the numbers of RBC's decreases blood viscosity.

Blood vessel radius is more likely to change because blood vessel length tends to stay pretty constant.

The longer the vessel length, the greater the resistance, therefore increasing the vessel length decreases flow rate.

Radius has a major effect because not can vasoconstrictor or vasodialate but also its multiply to the 4th power.

Obesity would decrease blood flow because blood vessels length can increases when we weight is gain.

The body establishes a pressure gradient for fluid due to the pressure difference between the two ends of the vessels.

Its directly related relationship, as the pressure increases flow will also increase. As viscosity increases then flow will decrease and if length of vessel increases flow decreases, if radius increase flow increases as well.

Diameter changes are easier for the body to change, pressure changes require the heart to be able to respond to a different force. In the cardiovascular system, the force of contraction of the heart provides the initial pressure and vascular resistance contributes the pressure gradient. If the heart changes its force of contraction, the blood vessel need to be able to respond to the change in force.

The frog heart has a single fused ventricle and we humans have 2 separate ventricles.

The higher the vagus nerve activity results in lower heart rate (negative chronotropic effect).

Sympathetic nervous system increases heart rate.

Too much vagal stimulation will essentially stop the heart, sometimes the sympathetic system encounters the changes and tries to compensate for the effect but sometimes its too late. The resumption of the heartbeat is referred to as vagal escape and can result of sympathetic reflexes or initiation of a rhythm by the parking fibers.

It would increase heart rate and increate to100bpm

Flight or Fright Sympathetic nerve fibers release Norepinephrine(noradrenaline) and Epinephrine (Adrenaline).

Increase the frequency of action potentials by binding to B1 adregenic receptor at the sinoatrial (SA) node.

Resting & Digesting Nerve fibers release Acetylcholine at their cardiac synapses.

Decreases the frequency of action potentials by binding to muscarinic cholinergic receptors at the SA node cell.

Indirectly opens potassium channels and closes calcium and sodium channels, decreasing the rate of depolarization and thus, decreasing heart rate.

cholinergic

Adregernic

Increase heart rate 79BPM

Increases heart rate 70BPM

Decreases heart rate 41 BPM

Decreases heart rate 45 BPM

The ventricle contraction is of greater force than the atrial contraction, this is due to the fact that ventricles function is to send blood throughout the body.

Amplitude does not change because the heart has long refractory period which prevents summation.

The extrasystole cannot occur until relaxation and so we could not achieve wave summation tetanus.

Cardiac cells have a longer action potential sf twitches than any other muscle cells therefore Do Not show temporal summation.

Through the sympathetic reflex and the initiation of rhythm by the Purkinji Fibers.

It increases the force of contraction while it decreases heart rate, increases stroke volume, slows Na+ pump.