Home
Browse
Create
Search
Log in
Sign up
Upgrade to remove ads
Only $2.99/month
Ch. 14
STUDY
Flashcards
Learn
Write
Spell
Test
PLAY
Match
Gravity
Terms in this set (64)
The human cardiovascular consists of:
the heart that pumps blood through a closed system of blood vessels.
Cardiovascular system is:
a closed loop.
arteries - carry blood away from the heart.
veins - return blood to the heart.
Materials entering the body:
- Oxygen from lungs to all cells.
- Nutrients and water from intestinal tract to all cells.
Materials moved from cell to cell:
- Wastes from some cells to liver for processing
- Immune cells, antibodies, clotting proteins from present in blood continuously to any cells.
- Hormones from endocrine cells to target cells.
- Stored nutrients to liver and adipose tissue to all cells.
Materials leaving the body:
- Metabolic wastes from all cells to the kidneys.
- Heat from all cells to the skin
- Carbon dioxide from all cells to the lungs.
Pulmonary circulation:
blood vessels that go from the right ventricle to the lungs and back to the left atrium.
Systemic circulation:
blood vessels carry blood from the left side to the tissues and back to the right side of the heart.
pressure gradients:
- is not the same thing as flow.
- liquids and gases flow down pressure gradieints from regions of higher pressure to regions of lower pressure.
Example: In humans, the heart creates high pressure when it contracts. blood flows out of the heart into the closed loop of blood vessels.
As blood moves through this system
- pressure is lost because of friction between the fluid and the blood vessel walls.
- pressure falls continuously as blood moves father from the heart.
Highest pressure is found:
aorta and systemic arteries as they recieve blood from the left ventricle.
Lowest pressure is found:
venae cavae, just before they empty into the right atrium.
driving pressure:
pressure created when the venticales contract.
when the walls of a fluid-filled container:
- Contracts, the pressure rises.
- Dilates, the pressure falls.
Risistance of a fluid flowing through a tube increases as the length of the tube
and the viscosity (thickness) of the fluid increases, and as the radius of the tube decreases. Of these factors, radius has the greatest effect on resistance.
Fluid through the tube is protortional
to the pressure gradient. A pressure gradient is not the same as absolute pressure in the system.
This pressure gradient is analogous
to the difference in pressure between two ends of a tube is directly proportional to the pressure gadient.
Flow rate:
is the volume of blood that passes one point in the system per unit time.
system per unit - time
Velocity:
is the distance a volume of blood travels in a given period of time. At a constant flow rate, the velocity of flow through a small tube is faster than the velocity through a large tube.
diameter
The heart:
- is composed mostly of cardiac muscle, myocardium. Most cardiac muscle is striated muscle.
- Lies in the center of the thoractic cavity just behind the sternum.
heart tissues:
- pericardium: {peri, around + kardia, heart} a thin layer of clear pericardial fluid inside the pericardium lubricates the external surface of the heart.
- Myocardium: cardiac muscle "thick", bulk of the heart.
- Endocardium is the inner most layer.
coronary arteries and coronary veins:
supply blood to the heart
Ventrical and Aorta
do not pump at the same time.
Pacemaker cells:
- set the rate of the heart.
myogenic:
- the heart can contract without connection to other parts of the body
-the signal for contaction is within the heart its self.
myocardial cells are linked to one another
by intercalated disks that contain gap junctions. the junctions allowes depolarization to spead rapidly from celle to cell.
intercalated disks have two components:
- gap junctions: in the intercalated disk electrically connect cardiac muscle cells to one another.
- desmosomes: are strong connections that tie adjacent cells together, allowing force created in one cel to be transferred to the adjacent cell.
In contractile cell excitation-contraction coupling, and action potential opens Ca2+ channels. Ca2+ from the (SR) through
calcium-induced calcium release.
The force of cardiac muscle
contaction can be graded according to how much Ca2+ enters the cell.
The action poteintals of mycardial contactile cells have a rapid depolarization phase created
by Na+ influx, and steep repolarization phase due to K+ efflux. The action potenitial also has plateaue phase created by Ca2+ influx.
Autorthymic myocardial cells have an unstable membrane potential called
pacemaker poteintial. The pacemaker poteintial is due to I channels that allow net influx of positive charge.
The steep depolarizion phase of the autorythmic cell action poteintial is caused by Ca2+ influx.
The depolarization phase is due to K+ efflux.
The electrical signal moves from the SA node through he internal pathway to the atrioventricular node (AV node), then into the AV bundle contractile cells.
- autorythmic cells in the right atrium that serves as the main pacemaker of the heart.
- highest pacemaker
- SA to AV is doing to have a delay
The SA node sets the pace of the heartbeat. If the SA node malfunction,
other autorythmic cells in the AV node or ventricles take control of the heart rate.
An electrocardium (ECG) is a surface recording of the electrical activity of the heart.
P-wave: represents atrial depolarization.
QRS-wave: represents ventricular repolarization.
T- wave: venterical repolarization
(Atrial repolarization is incorprated in the QRS complex.)
An ECG:
provides information on heart rate and rythm, conduction velocity, and the condition of cardiac tissues.
One cardiac cycle includes one cycle of contraction and relaxation.
Systole: is the condition phase
Diastole: is the relaxation phase
Most blood enters the ventricles while the atria are relaxed.
Only 20% of ventericular filling at rest is due to atrial contraction.
The AV valves prevent backflow of the blood into the atria.
Vibrations following closure of the AV valve create the first heart sound.
During isovolumic ventricular contraction:
the ventricular blood volume does not change, but pressure rises. When ventricular pressure exceeds arterial pressure, the semilunar valves open, and blood is ejected into the arteries.
When the ventricles relax and ventricular pressure falls, the semilunar valve close,
creating the second heart sound.
the amount of blood pumped by one ventricle
during one contraction is known as the stroke volume.
Diastole:
the time during which cardiac muscle relaxes
Systole:
the time during which the muscle contracts
One cardiac cycle:
inculdes one cycle of contraction and relaxation.
Most blood enters the ventricles:
while the atria are relaxed. Only 20% of ventricular filling at rest is due to atrial contraction.
The AV valves prevent back flow of blood into the atria.
Vibrations following closure of the AV valves create the first heart sound.
during isovolumic ventricular contraction:
the ventricular blood volume does not change, but pressure rises. When ventricular pressure exceeds arterial pressure, the semilunar valves open, and blood is ejected into the arteries.
When the ventricles relax and ventricular pressure falls, the semilunar valve close, close creating
the second heart sound.
The amount of blood pumped by one ventricle durning one contraction:
is known as the stoke pump.
Cardiac output:
is the volume of blood pumped per ventricle per unit time. It is equal to heart rate times stroke volume. The average cardiac output at rest is 5 L/min.
Homeostatic changes in cardiac output
are accomplished by varying heart rate, stoke volume, or both.
Parasyapthetic activity
slows the heart rate
Acetylcholine activates muscarinic repectors to hyperpolarize the pacemakers.
Sympathetic activity
speeds up the heart.
Norepinphrine and epinephrine act on B receptors to speed up the rate of pacemaker depolarization.
The x-axis
represents the end-diastole
The Frank-Starling law the heart:
says that increase in the end-diastolic volume results in greater stroke volume.
The longer a muscle fiber is when it begins to contact,
the greater the force of contraction.
Epinephrine and norepinephrine increase the force of myocardial contraction when they bind to B-adrenergic receptor.
They also shorten the the duration of cardiac contraction.
Preload:
on the heart stretch represent the load placed on cardiac muscles before they contract.
ED-V volume and preload are determined by venous return. Venous return is affected by skeletal muscle contractions,
the respiratory pump, and constriction of veins by sympathetic activity.
Contractility of the heart is enhanced by catecholamines and certain drugs.
Chemicals that alter contractility are said to have an inotropic effect.
Afterload is the load placed on the ventricle
as it contacts. Afterload reflects the preload and the effort required to push the blood out into the arterial system. Mean artrial pressure is clinical indicator of after load.
Catecholamines:
epinephrine and norepinphrine and drugs such as digitalis enhance contractablilty and are therefore considered to have a positive inotropic effect.
inotropic agent:
Any chemical that affects contractility.
Ejection fraction:
the precent of EDV ejected with a contraction (stroke volume/RDV), is one measure for evalulating venturing function.
YOU MIGHT ALSO LIKE...
Animal Physiology circulatory system
39 terms
ch 9
128 terms
Cardiovascular System
78 terms
Cardiovascular Physiology Chapter 14
126 terms
OTHER SETS BY THIS CREATOR
Perio final
25 terms
Spelling
4 terms
Perio Chapter 4
64 terms
Perio Chapter 3
39 terms
OTHER QUIZLET SETS
DAT BIOLOGY ALAN'S NOTES: VASCULAR SYSTEMS IN PLAN…
41 terms
RESPIRATION: PULMONARY BLOOD FLOW AND VE…
64 terms
urinary system
43 terms
chapter 19&20 the circulatory system
22 terms