what is the ciruclatory sytem composed of?

heart, blood vessels, and blood

what is the function of the circulatory system?

1. transports essential materials -- o2, fuel molecule, hormones. -- throughout the body to cell where they are needed and to collect waste materials generated by the bodys metabolic activity.

what two sections do the circulatory system divide into?

1. pulmonary circut -- blood vessels going to and from the lungs

2. systemic circuit - blood vessels goin to and from the rest of the tissues of the body.

explain the heart

four chambered, where muscular pumps that propels blood through the blood vessles

what divides the left and right side of the heart?

septum

why is the wall of the left ventricle thicker than that of the right?

because the systemic circulation is at a much higher pressure system thatn the pulmonary circulation

what is a heart mummur?

valve is damaged or the valve doesnt close properly.

meaning the blood regurgitates, causing noise.

what kind of muscle is in the heart?

myocardium -- cardiac muscle

why do cardiac muscles differ from skeletal muscles?

cardiac muscles are anatomically interconnected - functional syncytium

when one fibers contract, all the fibers contract

but the fibers of the aria are seperated from that of the ventricles.

where does the heart inherent ontractile rhythm?

the SA node. its the normal pacemaker of the heart.

the wave of depolarization is delayed in the A-V node for approx how long?

and why?

0.10 seconds

to give the atria time to contract and empty their content into the ventricles

what is electrocardiography?

and its component of a normal EKG waveform?

it records the wave of depolarization as it passes across the heart using electrodes on the surface of the body.

p waves - represnts atrial depolarization

QRS - ventricular depolarization

T - ventricular repolarization

what is an arrhythmia ?

hw do you diagnose it?

what are some examples of it?

- irregularity in the rhythm of the heartbeat

you diagnose it by looking at the heart rate, amplitude and shapes of the components of the EKG waveform, and time intervals

atrial - tachycardia

nodal - second and third degree heart blocks

ventricular - premature venticular contraction, ventricular tachycardia, ventrcular fibrillation

what is the widow maker?

cardiac muscles is dependent on aerobic metabolism -- rich blood supply

@rest: normal bloodf flow to the myocardim is 5% of the total cardiac output.

approx 70-80% of the oxygen is extracte from blood flowing int he coronary vessels compared to an average 30%

what is an artery?

explain its path

they carry blood away from the heart

large arteries -- medium -- small -- arterioles

theres less elastic tissue in the walls of the artery

why are arteries and arterioles important to the circulatory system?

they constitude the high pressure part of the circulatory system

by constricting or relaxing the thick layer of smooth muscles in the walls of the arterioles, blood flow can be increased or decreased to various cappilaries

all other organs of the cirulatory system exist only to serve what?

capillary beds

capillaries in the human body has what?

a surface area of 6000sq meters

60 000 miles long

mass is twice the size of the liver

what are venules and veins?

venules  - small vessels that conduct venous blood from capillaries to veins

veins - blood to the heart

what makes veins different from arteries?

they greater in diameter

have thinner walls

have both superficial and deep veins

smooth mucles allow them to change their diameter

low presure ofthe ciculatory system

where are valves found?

in those veins that carry blood against the force of gravity,

espcially those that of the leg

explain the mechanism invloved in returning blood to the heart

a) pressure differences b/w left ventricle and right atium

b)skeletal muscle pump; active muscles will squeeze the veins and push the blood towards the heart

c) respiratory pump - decreases the pressure in the thoracic cavity during inspiration.

what is blood composed of?

red, white blood cells, platelets

suspended in plasma (makes up 50-60% of blood by volume)

what is plasma composed of?

90% water and 10% solutes

explain RBC's

• also called erythocytes
• biconcave discs
• 5-6 milllion / cubic millimeter
• forned in bone marrow in ends of long and flat bones
• lifespan - 120days
• has hemoglobin

what is hemoglobin?

what are nomal values of hemoglobin?

contains protein which binds with oxygen

in men; 14-16g/100ml

females; 12-14g/100ml

what is hematocrit?

ratio of the volume of blood cells to that total volume of blood

where are the two sites of gas exchange in the body?

1. alveolar capillary membrane in the lung

o2 from alveoli -- blood

co2 from blood -- alveoli

2. tissue capillary membrane in tissues

o2 from blood -- tissues

co2 from tissues to blood

what is partial pressore of gas?

 what does it depend on?

-- the pressure of a gas in a gas mixture

dependent on: total barometric pressure

fractional concentration of that gas

what is the most important factor in determining gas exchange?

the partial presure gradient of the gases involved

ambient air vs tracheal air vs alveolar air

what is the functional residual capacity ?

a damper so that each incoming breath of air has only a smal effect on the composition of the alveolar air -- > PPG in the alveoly remains relatively stable

what is henry's law ?

what are its factors?

the amount of gas that dissolves in a fluid

1. the pressure of the gas above the fluid -- given by the gas concentration x barometric pressure

2. solublity coefficient of the gas

what is the diffusing capacity for oxygen ?

the volume of O2 that cross the a-c membrane / minute /mm HG btween the alveolar air and pulmonary capillary blood

what are the factors that affect partial pressure gradients?

1. thickness of the respiratory membrane

2. # of red blood cells or hemoglobin concentraiton

why? bc bound O2 doesnt exert a partial pressure

3. surface ares of the respiratory membrane avail for diffusion

what are the two mechanism for increaing the diffusing capacity by 3x its resting values during heavy aerobic exercise?

1. increaed lung volumes during exercise -- increase sa for diffusion

2. open more capillaries in the lungs

what is the bohr effect?

increased body temp, increased PCO2.. and decreas PH.

curve shifts to the rigt to release more oxygen at the tissue