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Anatomy and Physiology 2 (Exam 1)
Terms in this set (144)
the heart never rests, so how many times does it beat per day?
70 bpm= 100,000 bpd
The pulmonary circuit carries blood:
to and from the lungs.
the systemic circuit transports blood:
to and from the rest of the body.
What caries blood away from the heart?
Pulmonary arteries carry what:
02 poor blood to the lungs
What are capillaries?
thin-walled, microscopic vessels that connect the smallest arteries to the smallest veins.
What are exchanged with the tissues through the very thin-walls of the capillaries?
Gases, nutrients, and wastes.
What do veins do?
return blood to the heart.
What carries the most highly oxygenated blood?
Why are capillaries thin?
for simple diffusion.
What chamber of the heart receives O2 poor blood from the body and passes it to the right ventricle?
What chamber of the heart pumps blood to the lungs?
What chamber of the heart receives O2 rich blood from the pulmonary circuit and passes it to the left ventricle?
What chamber of the heart pumps blood into the systemic circuit?
the left ventricle
What is the thickest chamber of the heart?
the left ventricle, because it has to use a lot of pressure to pump the blood to the rest of the body.
Where does the heart lie?
the anterior mediastinum, space between the two lungs.
The base of the heart refers to what?
the attached superior end.
Where is the apex of the heart?
3 inches left of the midline of the body.
The heart is rooted such that an anterior view of the body would see what chambers?
the right atrium and the right ventricle
What is the pericardium?
A fibrous sac that surrounds the heart.
the pericardium consists of what two layers?
parietal pericardium and the visceral pericardium
What is the parietal pericardium?
outer layer of the pericardium
What is the visceral pericardium?
epicardium. the inner layer that clings to the heart.
What is the pericardial cavity?
the potential space between the two layers of the pericardium. It contains pericardial fluid that reduces friction between the beating heart and the surrounding tissues.
What is pericarditis?
It is inflammation of the pericardium. normally due to infection or trauma. It increases the friction. A doctor can normally hear a scratching noise with a stethoscope.
What is the epicardium?
the outermost layer of the heart wall. It consists of an outer layer of simple squamous EPI over an inner layer of areolar CT that clings to the myocardium.
What is the myocardium?
The muscular wall of the heart. it forms both atria and ventricles. It is composed of cardiac muscle tissue, blood vessels, and nerves. It consists of concentric nesting layers of muscle tissue.
What is the endocardium?
The innermost layer of the heart wall. It is composed of a simple squamous EPI that is continuous with the inner lining of the large blood vessels that attach to the heart. (eg. aorta).
Cardiac muscle is..
striated and made up of myofibrils (with sarcomeres).
Cardiac muscle cells (cardiocytes)
are quite small (50-100 um in length). Usually uninucleate.
Cardiocytes have mitochondria that make up what percentage of the cell volume
Cardiocytes have lots of myoglobin, which?
cardiocytes have adaptations for what?
efficient aerobic respiration.
In skeletal muscle, the trigger for contraction is the release of what from the SR?
In cardiac muscle, contraction involves what?
the influx of calcium into the cell through the larger t-tubules.
cardiocytes are typically
crdiocytes are connected ted to several other cardiocytes at special sites called
In Intercalated disces, the ends of the cells have a bumpy surface called what that increases the surface area for cell-cell connections?
In intercalated discs, the plasma membrane of adjacent cells are joined by
desmosomes and gap junctions
In intercalated discs, what resists stretching and helps transfer the force of contraction from cell to cell?
In intercalated discs, what allows the small molecules and ions to flow between the cells (thereby electrically connecting the cells)?
APs can travel quickly from
cell to cell
In a sense, the APs allow the cardiocytes of the two atria (or ventricles) to act like a..
single, huge cell
In cardiac muscle tissue, functions include Autorhythmic, which means?
the tissue that contracts without neural stimulation
in cardiac muscle tissue, functions include the timing of contractions is controlled by special muscle cells called
In cardiac muscle tissue, functions include Motor neurons that can influence the pacemaker and the
force of contraction
In cardiac muscle tissue, A function is that it is almost totally dependent on
Cardiac muscle is resistant to
in cardiac muscle tissue, twitches..
do NOT sum up as in skeletal muscle; therefore, the heart cannot produce a sustained contraction.
Why is it beneficial that twitch do not sum up in the heart?
if they became locked up, the heart couldn't pump blood.
the right atrium receives blood through what systemic circuit great veins?
the superior vena cava and the inferior vena cava.
The superior vena cava..
connects to the superior right atrium. carries deoxygenated blood from the upper body.
The inferior vena cava..
connects to the inferior right atrium. carries deoxygenated blood from the lower body.
The right atrium, when not filled with blood, the outer portion of each atrium (both right and left) deflates into a wrinkly flap called
What is the relatively thin wall spectating the right and left aorta?
From early embryonic development until birth, theres an oval opening through the intramural septum that connects the right and left atria. what is it called? why is this beneficial before birth?
foramen ovale. it bypasses the lungs.
after closing , the foramen ovale becomes a small, shallow depression that persists into adulthood. what is kit called?
Blood flows from the right atrium to the right ventricle through which valve?
the right atrioventricular valve, AkA tricuspid valve.
Why is is called the tricuspid valve?
it has three fibrous flaps, called cusps.
the free edge of each cusp is attached to connective tissue fibers called
these "cords" originate at what that are conical muscular projections from the inner surface of the right ventricle?
When the right ventricle contracts, the right AV valve closes and prevents the back flow of blood into the
What prevents the overextension of cusps
the inner surface of the right ventricle has a series of muscular ridges called
trabecular cameae "fleshy arches"
When the right ventricle contracts, it pumps blood through the pulmonary semilunar valve to enter the pulmonary trunk which starts the
The semilunar valves prevent what
back flow of the blood into the right ventricle upon relaxation of the ventricle.
the pulmonary trunk quickly divides into the right and left
After the exchange of gases in the lungs, oxygenated blood flows into the right and left
The right and left pulmonary veins deliver blood to the
Blood flows from the left atrium to the left ventricle through which valve?
Left atrioventricular valve (Bicuspid) (Mitral)
the left ventricle has muscle ridges called
a thick wall that separates the right and left ventricles
inter ventricular septum
blood is pumped by the strong left ventricle through the what into the ascending aorta
aortic semilunar valve
these semilunar valves prevent back flow of blood into the left ventricle upon
relaxation of that ventricle
Blood flows from the aortic arch into the
When the right ventricle contracts, it acts like a "bellows" and squeezes blood against the thick
When the powerful left ventricle contracts, all of its walls contract such that the ventricle both
shortens in length and decreases in diameter
When the left ventricle contracts, it does what to the right ventricular cavity?
When the heart beats, first the atria contract simutaneously then the ventricles contract simultaneously. What volumes does this send to the pulmonary and systemic circuits?
Although they have equal; volumes, which ventricle generates far more pressure?
What permits blood to flow in one direction only
The AV valves offer no resistance to blood flowing in into
ventricles from atria
What would happen in a patient whose papillary muscles or "Chords" were damaged?
each time the ventricle contracts, there would be regurgitation into the atria.
Unlike the AV valves, the semilunar valves neither have nor need
muscular braces. they require much less pressure to withstand. each semilunar has 3 cusps that brace each other in the closed position.
Vascular Heart disease happens when?
if the valves malfunction to the extent that the heart cannot pump efficiently
the fibrous skeleton of the heart consists of what tissue that encircles the heart valves as well as the bases of the aorta and pulmonary trunk?
dense band of tough elastic
Why is it important that the fibrous skeleton bands electrically insulate the cardiac cells of the ventricles from those of the atria?
because of the gap junctions.
Lots of what fibers support the structure of the heart?
collagen and elastic
The CT of the heart, these connective tissues:
1. physically support the muscle cells, nerve cells, and blood vessels of the heart
2. prevent overexpanison of the heart
3. help heart spring back into its original size after contracting
4. help distribute the force of contraction so that one area doesn't suffer most of the wear and tear
Since the heart is already working, its muscle cells need lots of
oxygen and nutrients
The blood supply to the heart is called the
The coronary arteries (right and left) emerge from the base of the
among the most variable aspects of all human anatomy.
Why does little blood flow in to the coronary artery when the left ventricle contracts?
the cusps of valve block them.
When the left ventricle relaxes, the stretched walls of the aorta
relax and recoil (elastic rebound)
elastic rebound pushes blood further into what two things?
the systemic circuit and the coronary arteries
What supplies blood to the right atrium and ventricle?
the right coronary artery
What supplies blood to both posterior ventricles?
Posterior Interventricular (descending) branch of the RCA
What runs along margin of left atrium
the left coronary artery
the left coronary artery splits into what two major branches
circumflex branch of the LCA and the anterior interventricular (descending) branch the LCA.
The circumflex branch of the LCA
supplies blood to the left atrium
the anterior interventricular (descending) branch of the LCA
supplies blood to both ventricles
What is anastomosis?
a convergence. such as when the anterior interventricilar branch of the LCA eventually joins to the posterior interventricular branch of the RCA.
Why is an anastomosis helpful?
if there is a blockage, it provides a backup route.
What vein drains the anterior heart and runs along the interventricular branch of the LCA
the great cardiac vein
What vein drains the blood from the posterior heart and runs alongside the posterior interventricular branch of the RCA
the middle cardiac vein
all the cardiac veins empty into the coronary sinus, which , in turn, empties into the
What is the coronary sinus?
a large, thin walled vein on the posterior of the heart.
TEST: all veins eventually empty into the vena cavae. True or false?
False. coronary sinus.
What is caused by a long-term insufficient supply of blood to one or more parts of the heart muscle that suddenly kills a patch of the myocardium? it also accounts for about 25% of all deaths in the US
heart attacks (myocardial infarctions)
Heart attacks poor blood supply is usually due to a __________ somewhere in the coronary arteries or ____________ of the coronary arteries
Angina pectoris (chest pain) is caused by
a short-term slow down or blockage of blood flow. A partially blocked coronary artery constricts temporarily. It is a sense of heaviness or pain in the chest.
In angina, with insufficient blood and oxygen, the cardiocytes switch to
What elevates levels of lactic acid, is a warning sign of blood supply to the heart being weak?
When would the pain of angina pectoris abate?
when the flow resumes.
The conducting system is a network of specialized ________ ___________ __________ that starts and spreads the electrical impulses through the heart that stimulate the heart to contract
cardiac muscle cells
Since it has its own conducting system, cardiac muscle contracts on its own because its
What are two types of cardiac muscle cells that are involved in normal heartbeat?
contractile cells and conducting cells
What muscle cell contracts and propels the blood
What are specialized muscle cells that coordinate the contraction? They make sure the contractile cells push blood in the correct direction and at the correct time. They are typically smaller than the contractile cells and have few myofibrils
The actual contraction lags behind the
What are the 6 components of the conducting system?
1. Sinoatrial node (SA node)
2. Internodal pathways
3. atrioventricular node (AV node)
4. AV Bundle (bundle of His)
5. Bundle Branches
6. Purkinje fibers
The conducting cells of both nodes (SA and AV) exhibit
prepotentials (pacemaker potential)
the cell membranes of conducting cells cannot maintain a stable
Why does the rate of spontaneous depolarization differ in different parts of the conducting system?
- the fastest is the SA node, which generates aPs at a rate of 80/min
-slower in AV node, 60APs/min
-because the conducting cells of the SA node reach threshold the fastest, the SA node establishes the heart rate.
The SA node is the
If SA node is the pacemaker, then why is resting heart rate usually much slower than 80 bpm?
because parasympathetic slows heart.
What would happen to heart rate if SA node's damaged?
AV node would now be fastest and set the pace at 50 bpm
What is located in the superior and posterior wall of the right atrium, near the entrance of the vena cava? It contains the pacemaker cells that establish heart rate.
What are the conducting cells in the atrial walls that connect theSA node to the AV node?
As the internodal pathways relay signal from the sa node to the av node, they also stimulate _______ _______ OF BOTH ATRIA TO CONTRACT
Once the contractile cells begin contracting, the ap spreads across the atrial cells by cell yo cell contact through
Contracting atrial cells do not pass the stimulus to the contractile cells of the ventricles because of the
What is located in the floor of the right atrium near the right av valve?
the atrioventricular node
The signal at the AV node is delayed because:
1. the conducting cells here are relatively small in diameters
2. there are fewer gap junctions between the cells.
Why is the delay at the AV node important?
because it ensure that the atria contract before the ventricles. It allows the ventricles to fill with blood.
What is the bundle of conducting cells that runs from the AV node to the interventricular septum and quickly divides into the bundle branches?
What occurs within the interventricualr septum? Both branches extend toward the apex, turn and fan out. The left is much larger than the right.
Bundle branches conduct the impulses to two places:
1. purkinje fibers
3. papillary muscles of the ventricles
conducting signals to the papillary muscles, ensures that the AV valves have time to close before the _______ ________ tighten
What spreads out from the apex of the heart to the base?
What pushes blood in the correct direction toward the pulmonary trunk and aorta?
When the ventricles begin contracting at the apex and the contraction spreads in a wave like fashion toward the base of the heart.
Because thepurkinje fibers are large in size,
they conducts Ads very quickly. thus, the signal to contract quickly reaches all the contractile cells of the ventricles so the ventricles contract in unison.
From end of purkinje fibers, signal spreads from. cardiocyte to cardiocyte through their
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