Chapter 5 - EMT (Circulatory/Cardiovascular System and Nervous System Control)

70-80 mL

=Stroke volume of adult With each beat, _____ mL blood is ejected from the adult heart

Constrict; rapidly; increases

After small loss of blood, the vessels ____ to provide an adjusted bed for the reduced volume of blood to fill. The heart pumps more ____ to circulate the remaining blood more efficiently. Pulse _____ to keep the cardiac output constant at 5-6 L per minute.

2-3 L

Amount of blood in vascular system in children

300 mL

Amount of blood in vascular system in infants

Cardiac output (CO)

Amount of blood moved in 1 minute In 1 minute, the entire blood volume (5-6 L) is circulated through all the vessels)

Stroke volume (SV)

Amount of blood moved in one beat (left ventricle) Weak left ventricle moves less blood per beat

Preload

Amount of blood returning to the heart Too little = blood pressure falls Too high = heart cannot move blood effectively

6-10 minutes

Amount of time it takes to clot

Loss of blood volume and increase blood pressure

Arteries contract/constrict to accomodate ____.

450 mL

At any one time, there is ____ mL of blood in the spleen

Gravity, skeletal muscle contraction, and intrathoracic pressure changes from breathing

Because pressure generated by the heart dissipates as blood passes through capillaries, venous blood flow is assisted by _____.

Pulmonary artery

Begins at right side of the heart and carries oxygen-depleted blood to the lungs Only artery that carries oxygen-depleted blood

Available blood is shunted into the major blood vessels, keeping them filled; Waste is not being removed and nutrients are not being delivered to the cells --> eventually tissues will become damaged if cellular waste is not removed

Benefit of sphincters; disadvantage

Arteries; veins

Blood enters an organ or tissue through the ____ and leaves it through the _____.

Oxygen-poor blood enters the superior and inferior venae cavae into the right atrium and passes through the tricuspid valve to fill the right ventricle. Tricuspid valve closes after right ventricle contracts, to prevent backflow. Contraction causes blood to flow through pulmonic valve into pulmonary artery and through pulmonary circulation through lungs. At the lungs (pulmonary capillaries), CO2 diffuses out and blood is refreshed with oxygen. This oxygen-rich blood travels to the left atrium via pulmonary veins, through the mitral valve and into the left ventricle. Contraction of left ventricle pumps blood through aortic valve into the aorta and to the arteries of the body, which deliver oxygen and nutrients to the tissues and pick up wastes/CO2. This blood travels back to right atrium via venules to superior and inferior venae cavae.

Blood flow cycle through the two circuits, starting with right side.

30%; 70%

Blood is unevenly distributed throughout the body ~ ___% of blood is found within the heart, arteries, and capillaries. The remaining ____% is found within the veins and venules (lower pressure)

Sphygmomanometer

Blood pressure cuff, used to measure blood pressure (high and low points) in mmHg (millimeters of mercury) High point = systolic blood pressure Low point = diastolic blood pressure (heart at rest)

Arteriovenous shunts

Built-in bypasses at the capillary level; some of the blood cells will exit the arteriole only to be shunted to the venule without ever reaching the true capillary (these blood cells do not get to offload their oxygen) May take several passes for any particular blood cell to actually reach the true capillaries where oxygen delivery and waste removal is done.

CO = HR x SV

Cardiac output (CO) equation

Carotid artery pulse (neck) and femoral artery pulse (groin)

Central pulses (2)

Plasma, RBCs (erythrocytes), WBCs (leukocytes), and platelets

Components of blood

92% water, 7% proteins (albumin to regulate oncotic pressure, clotting factors, enzymes, hormones), 1% oxygen, CO2 (as bicarbonate), nitrogen, nutrients, cellular waste (lactic acid), other products

Composition of plasma, the sticky yellow fluid that carries the blood cells and nutrients (liquid portion of blood)

Pulse

Created by the forceful pumping of blood out of the left ventricle and into the major arteries Palpated most easily at neck, wrist, and groin Present throughout the entire arterial system Found most easily where the larger arteries near the skin can be pushed against a solid structure like a bone or large muscle

Pulse pressure

Difference between systolic and diastolic blood pressures; provides information about the body's response to stress

Septum

Divides the heart down the middle into right and left sides

Depolarization; repolarization

Each mechanical contraction of the heart is associated with two electrical processes: ______ = electrical charge on surface of heart muscle cell changes from positive to negative; ______ = heart returns to its resting state and positive charge is restored to the surface

5-6 L

Entire blood volume in adult Amount of blood in vascular system in adult

Capillary vessels

Fine end divisions of the arterial system that allow contact between the blood and the cells of the tissues and exchange of oxygen and CO2 between tissues and blood cells Connect venules with arterioles Allow blood to move through a single cell at a time, which can result in a backup

Beta-1 receptors

Found in the heart When stimulated, cause heart rate to increase and squeeze harder with each contraction (increased force of heart contractions) to increase cardiac output

Beta-2 receptors

Found in the lungs When stimulated, causes dilation of bronchi (bronchodilation) which allows more air to be inhaled and exhaled, therefore more oxygen is available to the body

Alpha-adrenergic receptors

Found within blood vessels When stimulated, constricts blood vessels thereby increasing blood pressure, skin becomes pale, cool, and clammy

Filters/removes worn out blood cells, foreign substances, and bacteria from blood, recycles hemoglobin, assists in immune response

Functions of spleen

Spleen

Located in LUQ, part of lymphatic system but processes/filters blood

Perfuse blood throughout the body (Perfusion)

Main function of the cardiovascular system

Carbonic acid (H2CO3)

Majority of carbon dioxide is carried by conversion to ____, which dissolves in the plasma (Small amount carried by hemoglobin)

Blood flows into arterial side of capillary, pressure increases and water is forced out, yet at the same time water wants to enter capillary. Hydrostatic pressure is higher and water (carrying nutrients) leaves capillary and enters interstitial space. By the time the fluid reaches the venous side, the hydrostatic pressure is diminished and oncotic pressure is now higher. This causes water (with wastes from cells) to enter the venous side of the capillary. Wastes are then carried away.

Mechanism of hydrostatic and oncotic pressures on nutrient/waste exchange and water movement through capillary

Tunica media

Middle layer of the artery, where smooth muscles are found that can contract and dilate to change the diameter of the blood vessel

Perfusion

Movement of blood The circulation of oxygenated blood within an organ or tissue in adequate amounts to meet the cell's current needs

Electrical impulse begins high in atria at sinoatrial (SA) node, then travels to atrioventricular (AV) node, to bundle of His, and moves through Purkinje fibers to the ventricles. This movement produces a smooth flow of electricity through the heart, depolarizing the muscle and producing a coordinated pumping contraction.

Movement of electrical impulse in heart

60-100 beats/min

Normal resting heart rate in adult

Oncotic pressure

Opposing pressure to hydrostatic pressure Form of osmotic pressure exerted by proteins in the blood plasma that tends to pull water into the circulatory system These proteins make the blood thicker, and because there is more water outside the capillary than inside, diffusion occurs and water seeks to move into the capillary

loss of blood pressure

Organs, tissues, and cells are no longer adequately perfused or supplied with oxygen and food, and wastes can accumulate as a result of _____. Cells, tissues, or whole organs may die.

Radial artery pulse (wrist), brachial artery pulse (medial aspect of arm), posterior tibial artery pulse (posterior to medial malleolus/ankle bone), dorsalis pedis artery pulse (top of foot)

Peripheral pulses (4)

Hydrostatic pressure

Pressure exerted by a liquid and occurs when blood is moved through the artery at relatively high pressures. When that blood meets capillary walls, pressure of fluid pushes against the walls to force fluid out of the capillary Pressure of water against the walls of its container

Blood pressure (BP)

Pressure the blood exerts against the walls of the arteries as it passes through them The pulsed, forceful ejection of blood from the left ventricle of the heart into the aorta is transmitted through the arteries as a pulsatile pressure wave, which keeps the blood moving throughout the body

Afterload

Pressure to be overcome when the left ventricle contracts; pressure within the aorta Diastolic pressure is the same as this

Diastolic blood pressure

Pressure within the arteries when the heart is at rest Indicates adequacy of the amount of blood vessel contraction (arterial) and amount of blood within the blood vessels

Systolic blood pressure

Pressure within the arteries when the heart is contracting, left ventricular force Indicates heart pumping effectiveness and blood available to the heart

Aorta

Principal artery leaving the back left side of the heart; carries freshly oxygenated blood to the body Has many branches (i.e. coronary arteries, carotids, hepatic, renal, and mesenteric, etc.) Divides at the level of the umbilicus into two common iliac arteries that lead to lower extremities

Albumin

Protein that regulates oncotic pressure, thereby controlling the movement of water into and out of the circulation

Fighting infection (WBCs) Transporting oxygen (RBCs via hemoglobin) Transporting carbon dioxide (plasma) Controlling (buffering) pH (chemicals in plasma) Transporting of wastes and nutrients (water in plasma) Clotting/coagulation (platelets and clotting factors in plasma)

Six functions of blood

Sphincters

Small muscles in the arterioles that can be opened or closed. = Muscles arranged in circles that are able to decrease the diameter of tubes Found within blood vessels, rectum, and bladder E.g. when a patient is bleeding, chemical commands are sent for these to close, preventing blood cells from entering capillaries. Blood is shunted off to another venule while carrying oxygen

Interstitial space

Space between cells Nutrients move from capillaries, through the ____, and into the cells and wastes move in the reverse direction.

Baroreceptors

Special pressure sensors spread throughout the body that send signals to brain (through nervous system) and brain responds by turning on the sympathetic or parasympathetic nervous system Allow the brain to receive information about blood pressure, help maintain perfusion Mainly found in arch of aorta and carotid arteries, which ensures that the most vulnerable and most important cells get oxygen (heart and brain)

Shock (hypoperfusion)

State of inadequate circulation when it involves the entire body An abnormal state associated with inadequate oxygen and nutrient delivery to the metabolic apparatus of the cell If loss of blood is too great, adjustment fails, then patient goes into this state

Superior and inferior venae cavae, aorta, pulmonary arteries and veins

The "great vessels"

closed; capillaries

The circulatory system is entirely _____ with ______ connecting arterioles and venules.

Autonomic nervous system

The heart is under control of the _______. However, the heart has its own electrical system and continues to function even without this control

Aorta

The heart receives the first blood distribution from the ____.

Oxygen deficient, injured, or dies

The heart's electrical system becomes disturbed if part of the heart is ______.

smaller; higher

The higher the SVR, the _____ the container and therefore the _____ the pressure of blood within the vessel.

Veins

The right side of the heart receives blood from the ____ of the body.

Nervous system

The size of the arteries and veins is controlled by the _____ system according to the amount of blood available to keep blood pressure normal at all times.

Systemic Vascular Resistance (SVR)

The state of the blood vessels, how dilated or constricted they are The resistance to blood flow within all of the blood vessels except the pulmonary vessels The resistance that blood must overcome to be able to move within the blood vessels

Atrium; ventricle

The upper chamber of the heart; the lower chamber of the heart

Fine, circular muscle tissue (and sometimes elastic tissue, too)

The walls of an artery of made of ____.

Coronary arteries

These two arteries have their openings immediately above the aortic valve at the beginning of the aorta where the pressures are highest. These arteries supply the heart muscle itself with blood.

Brain and heart (and kidneys)

These two organs require a constant and continuous supply of oxygen Other tissues can function with less blood at rest

Chordae tendinae

Thin bands of fibrous tissue that attach to the one-way valves in the heart and prevent them from inverting.

Pulmonary

This circuit carries oxygen-poor blood from the right ventricle through the lungs, where it gives up CO2 and becomes refreshed with oxygen, and then returns to the left atrium.

Systemic

This circuit carries oxygen-rich blood from the left ventricle through the body, gives up oxygen and nutrients to tissues and organs, absorbs cellular wastes (CO2) and returns this blood back to the right atrium

Left

This side of the heart pump is more muscular and is a high-pressure pump, while the other side is a low-pressure pump

Systemic (in the body) and pulmonary (in the lungs)

Two circuits in the body

Epinephrine and norepinephrine

Two hormones secreted by the adrenal glands (stimulated by sympathetic nervous system) to stimulate the heart and blood vessels, allowing system to better cope with dangerous or unexpected situation

Hydrostatic pressure and oncotic pressure

Two main forces at work inside the capillary

(1) Arteriovenous shunts; (2) sphincters

Two systems to keep the blood cells moving and prevent backup in capillaries

Alpha- and beta-adrenergic receptors

Two types of receptors in heart and blood vessels related to sympathetic nervous system Prepare body for fight-or-flight

Valves

Unidirectional flow in the veins is governed by _____.

thinner; larger

Veins have much _____ walls than arteries and are _____ in diameter.

Systole; diastole

When a ventricle contracts ; when a ventricle relaxes and fills with bloods

Fluid leaves capillary

When hydrostatic pressure is greater than plasma oncotic pressure

Fluid enters capillary

When hydrostatic pressure is less than plasma oncotic pressure

Parasympathetic system

When stimulated, causes the heart to slow and beat more weakly (decreases heart rate and decreases force of contraction)

Changing the size of the total blood volume container

When the body changes blood flow to redirect blood flow to leg muscles when running or to stomach and intestines when eating, the body is actually ______.

Its hemoglobin is rich in oxygen

Why is arterial blood bright red?

Arteries; veins

_____ carry blood away from the heart; _____ carry blood to the heart.