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Chapter 14: Cardiovascular Physiology
Terms in this set (60)
a circulatory system comprising a heart, blood vessels, and blood
the microscopic vessels where blood exchanges material with the interstial fluid
Substances transported by the cardiovascular system can be divided into
1) nutrients, water, and gases that enter the body from the external environment
2) materials that move from cell to cell within the body
3)wastes that the cells eliminate
Transport in the cardiovascular system
Substance moved --> From --> To
Materials entering the body:
Oxygen --> Lungs --> all cells
Nutrients and water --> Intestinal tract --> All cells
Materials moved from cell to cell:
Wastes --> Some cells --> Liver for processing
Immune cells, antibodies, clotting proteins --> Present in blood continuously --> Available to any cell that needs them
Hormones --> Endocrine cells --> Target cells
Stored nutrients--> Liver and adipose tissue-->All cells
Materials leaving the body:
Metabolic wastes --> All cells --> Kidneys
Heat--> All cells --> Skin
Carbon dioxide--> All cells --> Lungs
Blood vessels that carry blood away from the heart
Blood vessels that return blood to the heart
septum of heart
heart is divided by this central wall
atrium and ventricle
- receives blood returning to the heart from the blood vessels
-pumps blood out into the blood vessels
right side receives blood from tissues and returns back to lungs for oxygenation, left side receives newly oxygenated blood from the lungs and pumps it to tissues throughout the body.
Under some conditions, low-oxygenated blood can impart a bluish color to certain areas of the skin - around the mouth and fingernails
From the right atrium, blood flows into the right ventricle of the heart and pumped through the pulmonary arteries
Cardiovascular system schematic
From the lungs, blood travels to the left side of the heart through the pulmonary veins
The blood vessels that go from the right ventricle to the lungs and back to the left atrium are known as this.
Blood pumped out of the left ventricle enters the large artery known as the aorta.
Branches into a series of smaller and smaller arteries that finally lead into network capillaries
Superior vena cava
The veins from the upper part of the body join to form this. Empties into right atrium
Inferior vena cava
The veins from the lower part of the body join to form this. Empties into right atrium.
Blood vessels that carry blood from the left side of the heart to the tissues and back to the right side of the heart
Coronary arteries, Coronary veins, coronary sinus
Coronary arteries - nourish the heart muscle itself
Coronary veins - empties directly into the right atrium at the coronary sinus
Digestive tract and liver
pressure gradients (delta P)
Why does blood flow?
Liquids and gases flow down from regions of high pressure to regions of lower pressure
Blood flows down a pressure gradient
The mean blood pressure of the systemic circulation ranges from a high of 93 mm Hg in the aorta to a low of a few mm Hg in the venae cavae
In a fluid is the force exerted by the fluid on its container.
A clot that stops the blood supply to part of the heart
If fluid is not moving, the pressure it exerts is this.
Study of fluid in motion
Pressure created in the ventricles - it is the force that drives blood through the blood vessels
Pressure changes can also take place in the blood vessels
Dilation of blood vessels --> blood pressure inside circulatory system falls
Constriction of blood vessels --> blood pressure in the system increases
Blood flow takes the path of least resistance
-An increase in the resistance of a blood vessel results in a decrease in the flow through that vessel.
Resistance increases, flow decreases; vice versa
Resistance is influenced by 3 components:
1.) Radius of the tube (r)
2.) the length of the tube (L)
3.) viscosity (thickness of fluid)
4. The expression for Poiseuille's Law says
1.) The resistance to fluid flow offered by a tube increases as the length of the tube increases
2.) Resistance increases as the viscosity of the fluid increases
3.) resistance decreases as the tube's radius increases
Resistance and radius
Radius of the tube has the greatest effect on resistance
decrease in blood vessel diameter
-decreases blood flow
increase in blood vessel diameter
-increases blood flow
the volume of blood that passes a given point in the system per unit time
-L/min or mL/min
-example: blood flow through aorta of a 70 kg man at rest is about 5 L/min
-how much volume blood flows past a point in a given period of time
velocity of flow
-the distance a fixed volume of blood travels in a given period of time
-how fast blood flows past a point
Mean Arterial Pressure (MAP)
primary driving force for blood flow
-influenced by cardiac output (volume of blood the heart pumps per minute) and peripheral resistance (the resistance of the blood flow through them)
heart lies in the center of this
a.) The heart lies in the center of the thorax
b.) Vessels that carry well-oxygenated blood are red; those with less well-oxygenated blood are blue
c.)The heart is on the ventral side of the thoracic cavity, sandwiched between the lungs
d.) Superior view of the transverse plane
e.)The heart is enclosed within a membranous fluid-filled sac, the pericardium
f.) The ventricles occupy the bulk of the heart. The arteries and veins all attach to the base of the heart.
g.) One-way flow through the heart is ensured by two sets of valves
h.) Myocardial muscle cells are branched, have a single nucleus and are attached to each other by specialized junctions known as intercalated disks.
Tough membranous sac that encases the heart
-pericarditis - inflammation of the pericardium, can create friction rubs - heart rubs against the pericardium
cardiac muscle, covered by thin outer and inner layers of epithelium and connective tissue
coronary arteries and coronary veins
running across the surface of the ventricles are smooth grooves containing these, which supply blood to the heart muscle.
In the embryo, the heart develops from a single tube
a.) Age: embryo, day 25 - The heart is a single tube
b.)By four weeks of development, the atria and ventricles can be distinguished. The heart begins to twist so that the atria move on top of the ventricles.
c.)Age: 1 year
The Heart and Major Blood Vessels
-The right atrium receives blood from the venae cavae and sends blood to the right ventricle.
-The right ventricle receives blood from the right atrium and sends blood to the lungs.
-The left atrium receives blood from the pulmonary veins and sends blood to the left ventricle.
-The left ventricle receives blood from the left atrium and sends blood to the body except for lungs.
-The venae cavae receives blood from the systemic veins and sends blood to the right atrium.
-The pulmonary artery (trunk) receives blood from the right ventricle and sends blood to the lungs.
-The pulmonary vein receives blood from the veins of the lungs and sends blood to the left atrium.
-The aorta receives blood from the left ventricle and sends blood to the systemic arteries.
between the atria and the ventricles
-prevent backward flow of blood
-named for their crescent moon shape
-between the ventricles and the arteries
-prevent backward flow of blood
collagenous tendons that connect on the ventricular side to flaps slightly thickened at the edge.
Opposite ends of the chordae are tethered to mound-like extensions of ventricular muscle
-stabilize the chordae tendinae
-valve that separates the right atrium and right ventricle has three flaps (RST)
valve between the left atrium and left ventricle has only two flaps
bicuspid valve is also called this.
-resemblance to the tall headdress worn by popes
between the left ventricle and the aorta
between the right ventricle and the pulmonary trunk
originating within the heart muscle itself
signal for myocardial contraction comes not from the nervous system but from specialized myocardial cells
-also known as autorhymthmic cells
-set the rate of the heartbeat
Cardiac muscle differs in significant ways from skeletal muscle and shares some properties with smooth muscle:
1.) Cardiac muscle fibers are much smaller than skeletal muscle fibers and usually have a single nucleus per fiber
2.)Individual cardiac muscle cells branch and join neighboring cells end-to-end to create a complex network.
3.) Gap junctions - in the intercalated disks electrically connect cardiac muscle cells to one another.
-allow waves of depolarization to spread rapidly from cell to cell
4.) The t-tubules of myocardial cells are larger than those of skeletal muscle, and they branch inside the myocardial cells
5.) Myocardial sarcoplasmic reticulum is smaller than that of skeletal muscle, reflecting the fact that cardiac muscle depends in part on extracellular Ca2+ to initiate contraction. In this aspect, cardiac muscle resembles smooth muscle.
6.) Mitochondria occupy about one-third the cell volume of a cardiac contractile fiber, a reflection of the high energy demand of these cells.
Specialized cell junctions in the myocardium where one muscle cell connects to the next.
-consists of gap junctions and desmosomes - strong connections that tie adjacent cells together, allowing force created in one cell to be transferred to the adjacent cell
EC coupling and relaxation in cardiac muscle
1.) An action potential that enters a contractile cell moves across the sarcolemma and into the t-tubules
2.)Where it opens, voltage-gated L-type Ca2+ channels in the cell membrane
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