Unit 4 Flashcards
The compartment labeled “A” in the above diagram is the _____. It receives venous (deoxygenated) blood from the body.
right atrium
The compartment labeled “B” in the above diagram is the _____. It contracts to send blood to the lungs for gas exchange.
right ventricle
The compartment labeled “C” in the above diagram is the _____. It receives oxygenated blood from the lungs.
left atrium
The compartment labeled “D” in the above diagram is the _____. It contracts to send blood to the entire body.
left atrium
The vessel labeled “E” in the above diagram is the ______. It is the initial conduit for deoxygenated blood to pass to the lungs.
pulmonary artery
The vessel labeled “F” in the above diagram is the ______. It is the initial conduit for all oxygenated blood to pass to the entire body.
aorta
The valve labeled “G” is generally called a _______. Don’t worry about left or right on this one. These one-way valves connect the top chambers of heart to the bottom ones.
Atrioventricular (AV) valve
The valve labeled “H” is generally called a _______. Don’t worry about left or right on this one. These one-way valves prevent back-flow of blood from adjacent vessels when the bottom chambers relax.
semilunar valve
OK, enough with that figure above. Let’s talk more about the myocardial cells. Cardiac muscle cells are held together, end-to-end, at complex junctions called ________ that consist of interdigitated
membranes.
intercalated disks
Within the junctions mentioned in the previous question (intercalated disks), the cells are physically tethered by these strong connections that allow force created in one cell to be transferred to the adjacent cell.
demosomes
These components of the junctions mentioned in Question 9 allow cardiac muscle cells to be electrically connected. These direct conduits
between myocardial cells allow waves of depolarization of to pass rapidly between cells, causing them to contract almost simultaneously.
gap junctions
These specific myocardial cells make up ~99% of the heart, are striated muscle, and have thick and thin filaments organized into sarcomeres.
contractile cells
These specific myocardial cells make up ~1% of the heart, and mostly lack thick and thin filaments. Rather they are specialized for passing
electrical signals around the heart.
conducting (autorhythmic) cells
This general category of vessel directly returns blood back to the heart atria.
veins
This general category of vessels directly receives blood from the heart ventricles.
arteries
These blood vessels are the primary site of vasoconstriction and vasodilation because they contain large amounts of smooth muscle.
arterioles
These blood vessels are where gas, nutrient, and waste exchange occurs in body tissues.
capillaries
These blood vessels receive deoxygenated blood from the vessels named in the previous question.
venules
The circuit of the cardiovascular system that conducts deoxygenated blood from the heart to the lungs and returns oxygenated blood back to the heart is called the _______.
pulmonary circuit
The circuit of the cardiovascular system that conducts oxygenated blood from the heart to body tissues and returns deoxygenated blood
back to the heart is called the _______.
systemic circuit
______ defines the amount of blood that is pumped by one ventricle during a single contraction.
stroke volume
The total volume of blood pumped by one ventricle during a given period of time (usually 1 minute) is called the ______.
cardiac output
This concept explains that the heart must pump all the blood that returns to it AND the force of heart contraction is determined by the volume of blood returning to it at any given moment.
Frank-Starling Law
______ is a term that describes all the electrical and physical events that happen in the heart during one contraction-relaxation cycle.
cardiac cycle
If we count the number of contraction – relaxation cycles that happen in 1 minute, that defines a person’s _______.
heart rate
The volume of blood entering the heart from the venous circulation at any given moment is technically called _______.
venous return
______ defines the volume of blood left in a ventricle at the end of its contraction phase.
end-systolic volume
______ defines the maximum amount of blood that a ventricle can hold when it is fully relaxed.
end-diastolic volume
______ describes the time when a heart chamber (atria or ventricles) are contracting and pumping blood.
systole
______ describes the time when a heart chamber (atria or ventricles) are relaxing and filling with blood.
diastole
In the SA Node figure above, these channels are open at the stage marked “4”.
If channels
The channels in the previous question got their name due to their
“funny” behavior of allowing both Na+ and K+ ions to pass through. However, these channels are MORE permeable to one of these ions, and that’s what leads to the net depolarization seen in stage “4” of the
SA Node diagram. Which ION are these channels more permeable to?
Na+
In the SA Node diagram above, these channels are open in abundance
at the stage marked “0”. No wonder there is a big depolarization, eh? Make sure to choose a type of channel from the list, not an ion.
voltage-gated Ca2+ channels
At the peak of the depolarization of a conducting cell, the channels in
the previous question close and these channels open, resulting in the
repolarization phase marked with a “3” in the left diagram above. Make sure to choose a type of channel from the list, not an ion.
slow K+ channels
In the SA Node diagram above, the part of the action potential marked with the “4” gets a special name to denote how it automatically climbs towards threshold. What is that special name?
pacemaker potential
OK, the remaining questions will target the right diagram. They sure
look cool, huh? First off, what is their resting membrane potential (phase marked “4” in above diagram)?
-90 mV
(Right diagram) . When contractile cells receive a depolarization from an adjacent
conducting or contractile cell, they immediately depolarize (stage marked “0” above) through the opening of these channels. Make sure to choose a type of channel from the list, not an ion.
Kvoltage-gated Na+ channels
(Right diagram) When the membrane potential reaches +20 mV (stage marked “1” above), channels for this ION open and close very quickly, causing a very brief repolarization.
K+
(Right diagram) After this brief repolarization, the plateau phase (marked “2” above) ensues and this flattening of the action potential is due to what kind of channels opening. Make sure to choose a type of channel from the list, not an ion. The ion that moves in from the interstitial fluid will lead to power strokes in the contractile cell and sarcomere shortening. See Figure 14.9 for more on this and we will talk about it in lecture.
voltage-gated Ca2+ channels
–> figure 14.9:
(Right diagram) After the channels mentioned in the previous question close, the cell will rapidly repolarize (phase “3” in the diagram above). This change in membrane potential is due to the opening of what kind of channels? Make sure to choose a type of channel from the list, not an ion.
slow K+ channels
These blood vessels have the smallest diameter. They are also the site of exchange for nutrients, wastes, and signal molecules between the
blood and body tissues since they are composed only of a single layer of loosely connected endothelial cells.
capillaries
These blood vessels deliver blood to specific tissues and the smooth muscle cells embedded in their walls give them variable resistance. These characteristics make them ideal for fine tuning blood flow to meet the metabolic demands of different tissues around the body.
arterioles
These blood vessels collect blood just after it has had a chance to exchange nutrients, wastes, and signal molecules with body tissues and start its return journey to the heart.
venules
These blood vessels have the widest diameters and therefore hold more than half of the blood in our bodies. They also typically run close to the surface of our skin, so they must have both fibrous tissue for
strength and elastic tissue for flexibility.
veins
These blood vessels are structurally reinforced with elastic and fibrous
tissue, since they must withstand the highest blood pressures.
arteries
When considering blood pressure, two values are always recorded. The ________ pressure represents the maximum pressure that occurs in an artery near the heart and follows ventricular contraction.
systolic
The ________ pressure represents the minimum pressure in an artery near the heart and coincides with ventricular relaxation.
diastolic
There are three main factors that determine your blood pressure at any given moment (i.e., when resting, exercising, etc.). One factor, referred to as _______, focuses on how hard your heart is working at
that moment. This factor combines the number of beats per minute and the volume of blood pumped per ventricular contraction, both of which are controlled by autonomic efferent pathways.
cardiac output
Another key factor in determining blood pressure is the water content
of the blood plasma. This factor is referred to as _______ and is regulated primarily by the kidneys with guidance from both autonomic
and hormonal efferent pathways.
(Total) blood volume
A third factor that influences your blood pressure, called ________, is determined by the variable diameter (or radius) of the arterioles. This
factor is mostly under tonic sympathetic control and strategically diverts more blood flow to hard-working areas and sends less blood
flow to less-essential organs at any given time.
Total peripheral resistance
With this last point in mind, it should (hopefully) seem logical that the skeletal muscles, liver, and heart muscle itself will all receive _______ blood flow during exercise due to increased metabolic demands.
(Choose from “More” or “Less”)
more
By contrast, it should also (hopefully) seem logical that the digestive system, urinary system, and reproductive organs will all receive ______ blood flow during exercise, since these organs will have lower metabolic activity at that time. (Choose from “More” or “Less”)
less
When high-levels of nitric oxide is released as a paracrine signal
molecule by neurons, that will cause ________ blood flow to those neurons.
increased
We will learn later that an infection or irritation in the skin stimulates
immune cells to release high levels of histamine and bradykinin. It should come as no surprise then that the area around the infection will
become red and swollen due to _______ blood flow.
increased
By contrast, when you have a cut in the skin, thrombocytes (platelets) in the blood will be attracted to the area and release high levels of serotonin. This signal molecule stimulates _______ blood flow in the damaged area to limit its loss from the body as the injury is repaired.
decreased
When body tissues (e.g., skeletal muscles) have very high levels of oxygen present, this gas acts as a paracrine signal, leading to _______ blood flow to that area. This change allows cells in the area to use up
the surplus oxygen and return conditions to homeostasis.
decreased
When body tissues (e.g. skeletal muscles) are very active, they will increase their production of ATP. This in turn causes more production
of carbon dioxide and H+ ions, which ultimately decreases the pH of those tissues. Under these conditions, the carbon dioxide and H+ ions
will act as paracrine signals to cause _______ blood flow through that area to help return conditions to homeostasis.
increase
Vasopressin is a neurohormone released by the posterior pituitary. It
is released at high levels when the body becomes dehydrated and has
drop in total blood volume, which leads to a drop in blood pressure. Vasopressin therefore acts as a _________ to increase peripheral
resistance around the body and help to bring blood pressure back up.
vasoconstrictor
Low levels of hormone called angiotensin II are produced when the body is overhydrated and has high blood volume, leading to elevated blood pressure. Under these conditions, angiotensin II functions as a
______ to help bring blood pressure back down.
vasodilator
Natriuretic peptides are hormones that are produced at high levels when blood volume and blood pressure are high. Therefore, under
these conditions, these hormones function as a ________ to help bring
blood pressure back down.
vasodilator
There are two main types of capillaries scattered around the body. _______ are located in areas that need maximum exchange between the blood and interstitial fluid, such as in capillaries passing through
the kidneys or around the small intestines. These capillaries are extremely leaky, due to their loose junctions between endothelial cells
and pores in their plasma membrane.
fenestrated capillaries
All other areas of the body that just need regular levels of exchange between the blood and interstitial fluid have _______. These capillaries are only moderately leaky at the junctions between
endothelial cells.
continuous capillaries
These porous blood vessels are not technically capillaries, but they do allow for exchange of blood cells and plasma proteins with surrounding tissues. They are also much wider than standard capillaries. These
kinds of vessels are found only in the bone marrow, liver, and spleen.
sinusoids
Levels of oxygen, glucose, amino acids, and hormones are higher in the blood plasma passing through capillaries, relative to the interstitial fluid around nearby body cells. By contrast, metabolic wastes, such as carbon dioxide, creatinine, or urea, are released by cells. The level of these molecules is higher in the interstitial fluid than in the blood plasma passing through nearby capillaries. Movement of these solutes
into or out of the leaky capillaries occurs down their individual concentration gradients by the process of ______.
diffusion
Large proteins that are too bulky to pass through loose junctions between endothelial cells or fenestrations use a different mechanism to leave the blood plasma. They enter capillary endothelial cells by
endocytosis, get trafficked across the cytoskeleton in vesicles, and then
leave these cells by exocytosis to join the interstitial fluid of tissue
cells. This membrane transport mechanism is called ________.
transcytosis
When water leaves capillaries and enters the interstitial fluid around tissue cells, that process is called _______.
filtration
When water enters capillaries and leaves the interstitial fluid around
tissue cells, that process is called _______.
absorption
Two pressures dictate how much water leaves a capillary and how much enters it. This pressure drives absorption and uses osmotically-
active solutes to pull water from the interstitial fluid into the capillaries.
colloid osmotic pressure
This pressure drives filtration and describes the pressure pushing out against the inner walls of the capillaries. This pressure is also typically
synonymous with “blood pressure”, at least for the intents and purposes of this class.
hydrostatic pressure
When more water leaves a capillary network than enters it, tissue swelling, more technically called ______, will occur in that localized area.
edema
This is the term for the liquid matrix of the blood. It is made up of 92% water, 7% dissolved proteins, and 1% other dissolved biomolecules.
plasma
The liquid matrix mentioned in the previous question is identical to
interstitial fluid, except for the presence of ______ in blood.
plasma proteins
This is the most abundant protein in the liquid matrix of the blood. It makes up about 60% of the total protein content of that fluid.
albumin
This protein dissolved in the liquid matrix of the blood is essential for creating clots after an injury to the vascular system occurs.
fibrinogen
Another important category of protein that is dissolved in the liquid matrix is _________, which provide defense from foreign invaders by
binding to their surface and “tagging” them for destruction.
immunoglobulins
The technical name for red blood cells is _______. They lose their nucleus by the time they enter the bloodstream, where they carry oxygen and carbon dioxide. They also only live for about 4 months.
erythrocites
The technical name for white blood cells is _______. They are cells of the immune system and defend the body against pathogens.
leukocytes
These cellular elements, commonly called platelets, also lack a nucleus and are critical for blood clotting after a vascular injury.
thrombocytes
The larger cell type that platelets split off from during development is
called a __________.
megakaryocyte
All the cellular elements in blood are descended from a single precursor cell type known as a __________ stem cell.
pluripotent hematopoietic
The cell type noted in the previous question resides in the _______ , and can develop into many different cell types.
bone marrow
______ is the term for the synthesis of blood cells, which begins
during embryonic development and continues throughout a person’s
life.
hematopoiesis
Signal molecules in this general category control the process named in
the previous question. They are made on-demand (not stored in vesicles) by any nucleated cell and travel through the blood stream.
cytokines
This specific signal molecule stimulates hematopoietic stem cells to
grow and differentiate into all types of blood cells, especially white
blood cells.
colony-stimulating factors
This specific signal molecule influences the growth and differentiation
of red blood cells specifically. It is produced by the kidney.
erythropoietin
This specific signal molecule influences the growth and differentiation of the parent cell for platelets.
thrombopoietin
The ratio of red blood cells to plasma is indicated clinically by the
_____ and is expressed as a percentage of the total blood volume.
hematocrit
Because each red blood cell has lost its _____, they cannot synthesize
new proteins to maintain their membrane or enzymes to carry out
other repair processes. This contributes to their short, 4-month
lifespan.
nucelus
Because red blood cells lack ___, they must rely on glycolysis for their
ATP production.
mitochondria
In some red blood cell disorders, the shape or ______ of the cells can
give clues as to the specific disease.
morphology
For example, in this disorder, the red blood cells change shape to
resemble a crescent. This abnormal shape causes these cells to jam up
in small blood vessels, blocking blood flow to tissues, which causes
tissue damage and sometimes extreme pain.
sickle cell disease
When red blood cells are microcytic, often due to an iron deficiency, their _____ is abnormally small.
mean corpuscular volume
This protein is the main component of red blood cells and is best
known for its role in transporting oxygen. We will also see in lecture
that it also transports carbon dioxide as well as hydrogen ions.
hemoglobin
When blood cells are removed from circulation, the liver converts
remnants of the molecule named in the previous question into a
colored pigment called ______.
bilirubin
The pigment mentioned in the previous question is then used to synthesize _____, which is an important part of the digestive process.
bile
If a person has very low levels of hemoglobin in their blood, they have
a condition called _____. This condition can be caused by accelerated
red blood cell loss or decreased red blood cell production.
anemia
This term includes all the physiological mechanisms engaged to keep
blood within a damaged vessel.
hemostasis
As soon as vessel damage occurs, the first step in repair is a reflex that
causes release of paracrine signal molecules that cause _____ in the
immediate area, which minimizes blood loss. Putting pressure on a
bleeding wound also aids in this underlying process.
vasoconstriction
Exposed collagen fibers at the site of damage will cause ______ to adhere and start the process of clotting.
platelets
When the cells mentioned in the previous question adhere to the collagen, they become activated and release ____ into the area around
the injury. Two specific examples are serotonin and thromboxane A2,
which are localized vasoconstrictors to again help minimize blood loss.
cytokines
The secretion of the specific signal molecules mentioned in the previous question, along with another called platelet-activating factor
(PAF), stimulate more platelet aggregation and more secretion of these
signal molecules. This is an example of a (positive or negative)
feedback loop.
positive
The final hemostatic mechanism is called the ______ and occurs when
a fibrin protein mesh ensnares erythrocytes and stabilizes the platelet
plug to form a clot (see Figure 16.11b for a visual).
coagulation cascade
Once the damaged vessel is repaired through the process of mitosis,
the clot retracts when the fibrin mesh is slowly dissolved by an enzyme
called ____.
plasmin
Hemostasis is a delicate balance between too little response (which
can lead to excessive bleeding) or too much, which could create a ____
that can block blood flow in an undamaged vessel and deprive all its
tissues of vital nutrients.
thrombus
______ are chemicals released by endothelial cells that prevent
coagulation from taking place.
anticoagulants
The body naturally produces three of the molecules mentioned in the
previous question. Two of these have fairly obscure names, like
protein C and antithrombin III, but the third is commonly used in a
clinical setting to prevent a blood sample from clotting prior to
analysis. It is called______.
heparin
People who are at risk of developing small blood clots are sometimes
told to take one ____ tablet every other day to thin the blood.
However, this chemical does not really affect blood viscosity. It
actually prevents platelet plug formation and therefore helps to inhibit
clot formation and prevent heart attacks or strokes.
acetylsalicylic acid (aspirin)
This is the best-known coagulation disorder where one of the factors in
the coagulation cascade is either defective or lacking, leading to
excessive bleeding.
hemophilia
