Test One Flashcards
Signals from bio208
Signals can be:
Chemical messages: different ions (Ca); neurotransmitters (acethylcholine); different hormones (which ones did you mention in BIO208? - see
slide 10 if you forgot or my last point in the notes here)
or Electrical messages, such as
- messages for communication - transport: different ions involved in membrane potential changes (Na, K)
- Action potential travelling through a neuron (fast)
- Events at the synaptic cleft or a neuromuscular junction (a bit slower as multiple cells involved)
- Transport of PTH or calcitonin through blood (slowest)
more on a slower response system in the body - your endocrine system and introduce hormones as
chemical signals. Hormones can be proteins, peptides, steroids, amines and glycoproteins that travel through the body via blood stream to
“affect the activity only of its target cells; that is, cells with receptors for that particular hormone. Once the hormone binds to the receptor, a
chain of events is initiated that leads to the target cell’s response. Hormones play a critical role in the regulation of physiological processes
because of the target cell responses they regulate” (From Open Stax Anatomy & Physiology).
Monitoring blood calcium levels
Signals: Calcium, Calcitonin, PTH, Osteoclast, Osteoblast
Transported to: From thyroid/parathyroid to osseous tissues / renal tissues (kidneys) / digestive tissue (intestine)
From Open Stax Anatomy & Physiology:
“Figure 17.16 Parathyroid Hormone in Maintaining Blood Calcium Homeostasis Parathyroid hormone increases blood calcium levels when
they drop too low. Conversely, calcitonin, which is released from the thyroid gland, decreases blood calcium levels when they become too
high. These two mechanisms constantly maintain blood calcium concentration at homeostasis.” What is figure 17.16 an example of? An
endocrine system response related to parathyroid/thyroid gland role in calcium balance as a negative feedback loop. The negative feedback
loops are the basis of homeostatic balance or physiological regulation in the body. In addition to continually including endocrine system and
hormones, we will always discuss negative feedback loops as they play a key role in balance in the body (and endocrine system). Part 3a is
what you have focused on in BIO208 - we will talk more about 3b in unary system lectures in BIO209.
What we can use this figure for, is to illustrate how or why an endocrine system can involve a slower response - the signals are transported via
blood, which circulate through the body, which take more time than transport between neurons and other cells, for example (direct
communication or link)
What is blood
Blood is composed of plasma and formed elements. Plasma contains mostly water, proteins, and other solutes. Formed
elements contain red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. Hormones are secreted into the blood and
circulate in the plasma mostly via transport proteins (or freely).
Figure 18.2 illustrates normal composition of blood on the left, anemic blood (with low composition of hematocrit of % of erythrocytes), and
plychetemic blood (elevated composition of hematocrit).
“Figure 18.2: The cellular elements of blood include a vast number of erythrocytes and comparatively fewer leukocytes and platelets. Plasma
is the fluid in which the formed elements are suspended. A sample of blood spun in a centrifuge reveals that plasma is the lightest
component. It floats at the top of the tube separated from the heaviest elements, the erythrocytes, by a buffy coat of leukocytes and platelets.
Hematocrit is the percentage of the total sample that is comprised of erythrocytes. Depressed and elevated hematocrit levels are shown for
comparison.
What’s in a blood vessel
water, proteins, nutrients, blood cells (erythrocytes and leukocytes), platelets, hormones, ions/solutes
Lymphatic system transport
Another type of transport system that we will focus less on is the lymphatic system (lymph vessels, lymph nodes and organs, such as thymus
and spleen). Lymph contains a fluid (interstitial fluid) and white blood cells. Blood and lymph both circulate through the body and depending
on the distance needed to travel can represent a slow signal and slow response. In Figure 21.2 on the left, you can see the main vessels and
nodes of the lymphatic system in green but what should be also visible is the connection between the lymphatic system and the blood
vessels (example of the capillary network where exchange of nutrients, oxygen, carbon dioxide and other solutes happens). In Figure 21.4 on
the right, you can also seen that the lymphatic system drains into the circular system via thoracic duct on the left and the lymphatic duct on
the right into some of the main large veins (which we will cover in more details in a few lectures)
Blood/Lymph Connection: Lymph enters the venous section of the cardiovascular system through thoracic duct and right lymphatic duct.
Why the connection? Return the fluid to the blood (lymph = fluid and white blood cells,“recycled blood plasma”) - the fluids is rich in white
blood cells for immune system response and protection of the body
Lymphocytes and their functions
Where do the white blood cells that exist in lymph and blood develop?
There are two different developmental origin of different types of white blood cells that play a role in defence against foreign bodies in your
body (one origin leads to the development of red and white blood cells and the other to the development of different lymphocytes).
From Open Stax Anatomy & Physiology:
Figure 21.5 Hematopoietic System of the Bone Marrow All the cells of the immune response as well as of the blood arise by differentiation
from hematopoietic stem cells. Platelets are cell fragments involved in the clotting of blood.”
Compare and contrast nervous and endocrine
system signal.
Nervous system
Speed: fast
Distance: short
Organ system connections: nervous to any other system
Endocrine
Speed: slowest
Distance: long
Organ system connections: endocrine to any other system
Blood
Speed: slower (cycles of circulation)
Distance: long
Organ system connections: Involved in transport of signals/nutrients and messages for all systems
Lymph:
Speed: slower (cycles of circulation)
Distance: long
Organ system connections: Drainage into cardiovascular system (venous system)
locate your heart! How big is it?
In thoracic
cavity
• Medially
between the
lungs (rather
central than to
the left)
The heart is positioned above the diaphragm, posterior to the sternum, and between the lungs in the thoracic cavity (medially but slightly to
the left of the body in the thoracic cavity.
Do you remember what saggital view refers to? views in sagittal plane split the body in right and left views. In videos, I will be using Visible
Body but here I will use Complete Anatomy. You may have used other 3D viewing software or apps in BIO208 and you can use whatever
works best for you but please note that we will use 3D visualization aids less in BIO209 as I will just occasionally use them to help you
understand the positioning of a structure or different views of a structure.
How is your heart protected in the thorax?
Heart is protected by the pericardium in the pericardial cavity. In addition to the most outer fibrous pericardium, beneath this layer the heart is
further lined with serous pericardium, which consists of two layers: the outer parietal serous layer and the inner visceral (viscera - closer to
organ) serous layer, also known as epicardium. Below the epicardium if the muscle layer of the heart or the myocardium and the inner lining of
the heart (the lining outlining all the chambers) is the endocardium.
Protected by
pericardium in
pericardial cavity
• Layers: fibrous
pericardium,
parietal & visceral
layers of serous
pericardium,
myocardium and
endocardium
What are some key external heart features?
In the anterior view of the heart you can see the apex, right and some of the left atria (auricles are the muscular pouches of atria), you also see
mostly right ventricle but also a large part of the right ventricle. Of the major vessels associated with the heart, you can see the superior and
inferior vena cava (the major vein bringing blood to the heart from the body) and aorta divided into ascended aorta, aortic arch, descending
aorta (the major artery sending blood from the heart to the body), You also see pulmonary arteries and veins which are heart’s connections to
the lungs. You also see coronary arteries and veins which are smaller vessels that provide blood supply to the hard working cardiac muscle.
In the posterior view of the heart you can see the apex, left atria and right atria, complete left ventricle and most of the right ventricle .Of the
major vessels associated with the heart, you also see superior and inferior vena cava, and aorta and the pulmonary veins and arteries. You
also see coronary sinus, which is a larger blood vessel that divides into coronary arteries and veins.
What are some key internal heart features?
To view internal heart structures, we are looking at the anterior view with some of the heart chambers in frontal sections. Between right atrium
and ventricle you see the tricuspid valve with chord tendinae attaching this valve to the inferior part of the right ventricle. On the left side, we
see the bicuspid valve between the left atrium and left ventricle. You also see the valves in the major blood vessels connected with the
ventricles that send the blood towards the body or the lungs. On the left side is the aorta with the aortic valve and on the right side is the
pulmonary artery with the pulmonary valve. These are all one-way valves, meaning that they only allow blood from from atria to ventricles or
from ventricles to major blood vessels.
How does the blood flow through the heart?
To help us discuss blood flow, we can also look at the transfers section of the heart, right at the level between the atria and ventricles.
Blood flow through both sides of the heart happening simultaneously (check some of the animations I included in the video lecturette page for
Module 2 to help you visualize how heart’s left and right side work together at the same time.
Blood flow through the heart on the R side:
- from the body via superior/inferior vena cava into right atrium (blood low in oxygen)
- from the right atrium through the tricuspid valve into right ventricle
- from the right ventricle through the pulmonary valve into pulmonary arteries to the lungs (to be oxygenated)
Blood flow of the heart on the L side:
- from the lungs via pulmonary veins into left atrium (blood rich in oxygen)
- from the left atrium through the bicuspid valve into left ventricle
- from the left ventricle through the aortic valve into aorta to the rest of the body
What is special about cardiac muscle?
Striated,
shorter, thinner
• Less t-tubules
and low
calcium stores
• Rich in
mitochondria
and intercalated
discs Myocardium or cardiac muscle is similar in striated appearance to the skeletal muscle, but there are some structural differences that also
result in differences in electrical conductivity through the muscle. Because of lower amount of t-tubules in cardiac muscles, there are less
calcium stores so supply is needed and this muscle is rich in mitochondria because of constant and hard work of the muscle tissue. You can
also see intercalated disks rich in desmosomes and gap junctions, which ensure that all sections of the muscle are well connected with each
other and signal (ions) can move fast through different muscle sections so that cardiac contraction can be synchronous.
What is special about cardiac muscle electric potential
Slow influx,
prepotential
• Rapid influx of
calcium,
depolarization
• Outflux of
potassium,
repolarization
The electrical potential of the heart takes place in conductive heart cells (which result in electrical conduction cause a contraction in
contractile cells of the heart). You are looking at how an action potential moves through the electrical conducting cells. We see a slow influx
of sodium, which depolarizes the membrane to a threshold (movement os sodium inside the cells to increase the positive polarity of the
membrane by influx of positive ions). What speeds up this depolarization is the calcium, which does so rapidly and then it is the outflow of
potassium, just like in the action potential in the neurons that repolarizes the membrane.
The prepotential is due to a slow influx of sodium ions until the threshold is reached followed by a rapid depolarization and repolarization. The
prepotential accounts for the membrane reaching threshold and initiates the spontaneous depolarization and contraction of the cell. Note the
lack of a longer resting potential.
Here, we are looking at action potential through the contractile cells of the heart, which result in cardiac muscle contraction. Note the plateau
as the calcium cahnnels open and influx of calcium is slower so that depolarization of the cardiac muscle is longer and therefore the resulting
contraction is longer in duration.
Its own
conduction
system
• Sinoatrial (SA)
node
• Atrioventricular
node (AV)
• AV and bundle
branches
• Purkinje fibers
We mentioned that the electrical potential of the heart takes place in conductive heart cells. In this slide, you are now viewing, the electrical
conducting cells and pathways in the heart. Note the two nodes, the sinoatrial (SA) and atrioventricular (AV) nodes. SA node is self-pacing
centre of the heart, while the AV node controls the electrical conduction to the ventricles. The signal starts at the SA node and is sent to AV
node via intermodal conducting pathways. From AV node, signal is sent via AV bundle (or bindle of His) to the wall between right and left
ventricle, specifically to the right and left bundle branches, which then branch off throughout the ventricle wall and also branch off into smaller
conducting pathways in the ventricles, the Purkinje fibers.
How does cardiac conduction work
Rest
• 2: Action potential
(AP) at SA node
and across atria
• 3: AP at AV node,
atria contract
• 4: AP through AV
bundles
• 5: AP though ventricles
Heart
Module 2
• 6: ventricles contract
(repolarization)
(1) The sinoatrial (SA) node and the remainder of the conduction system are at rest (moment of closure of potassium channels). (2) The SA
node initiates the action potential, which sweeps across the atria. (3) After reaching the atrioventricular node, there is a delay of approximately
100 ms that allows the atria to complete pumping blood before the impulse is transmitted to the atrioventricular bundle. (4) Following the
delay, the impulse travels through the atrioventricular bundle and bundle branches to the Purkinje fibers, and also reaches the right papillary
muscle via the moderator band. (5) The impulse spreads to the contractile fibers of the ventricle. (6) Ventricular contraction begins.
How do we assess cardiac function?
P wave - atrial depolarization
QRS - ventricular depolarization
T wave - ventricular repolarization
PR interval - events at the atria
QT interval - events at the ventricles
P-R segment - time during which atria contract (no line deflection - no ion movements)
S-T segment - time during which ventricles contract (no line deflection - no ion movements)
(1) The sinoatrial (SA) node and the remainder of the conduction system are at rest (moment of closure of potassium channels). (2) The SA
node initiates the action potential, which sweeps across the atria; P wave - atrial depolarization
(3) After reaching the atrioventricular node, there is a delay of approximately 100 ms that allows the atria to complete pumping blood before
the impulse is transmitted to the atrioventricular bundle; P-R segment - time during which atria contract (no line deflection - no ion
movements); (4) Following the delay, the impulse travels through the atrioventricular bundle and bundle branches to the Purkinje fibers, and
also reaches the right papillary muscle via the moderator band; QRS - ventricular depolarization (5) The impulse spreads to the contractile
fibers of the ventricle; S-T segment - time during which ventricles start contracting (no line deflection - no ion movements)
(6) Ventricular depolarization begins
What is a cardiac cycle
• Time between
atrial contraction
and ventricular
relaxation
• Contraction:
systole
• Relaxation:
diastole
The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the cardiac cycle (Figure 19.27).
The period of contraction that the heart undergoes while it pumps blood into circulation is called systole.
The period of relaxation that occurs as the chambers fill with blood is called diastole. Both the atria and ventricles undergo systole and
diastole, and it is essential that these components be carefully regulated and coordinated to ensure blood is pumped efficiently to the body
How else do we assess cardiac function?(sounds)
Lub (S1) is the sound that the closure of the atrioventricular (tricuspid and bicuspid) valves makes. Dub (S2) is the sound of semilunar(aortic
and pulmonary) valve closures. Semilunar valves close (dub or S2) as the cardiac cycle ends and ventricles complete ejection of the blood
from the ventricles into the blood vessels carrying the blood away from the heart. Atrioventricular valves close (Lub or S1) as the first phase of
ventricular contraction begins and the ventricles have completely filled with blood.
What is cardiac output
Cardiac output
(CO) is the amount
of blood pumped
by each ventricle
in one minute
• CO depends on
heart rate and
stroke volume
(SV)
We assess or measure cardiac function through cardiac output. Specifically cardiac output (amount of blood pumped through the heart in a
minute) depends on heart rate and stroke volume. Heart rate is affected by autonomic innervation, hormones (see Slide 19) as well as fitness
level and age. Stroke volume (how much volume of blood can the heart pump) is determined by heart size, fitness levels, gender, contractility
of the heart muscles, duration of contraction, how much blood did the heart receive (preload) and how much resistance is there to sending
blood out of the heart (after load). You will discuss cardiac output in relation to exercise in much more detail in next case study in tutorials (just
before your first term test)
What factors affect heart rate
What factors affect heart rate (HR)?
Figure 19.33
Heart structures Blood flow Cardiac conduction
Figure 19.32
Sympathetic nervous system; release of
norepinephrine; increased levels of CO2, low
blood pressure; exercise or anticipation of
physical exercise; increased thyroid
hormones; decrease in sodium, potassium
and/or calcium; increase in body
temperature; stimulants
Here you are seeing how heart rate is affected by autonomic innervation. Vagus nerve has a parasympathetic signal to the heart to slow down
the heart rate, while the sympathetic cardiac nerves send a signal to increase the heart rate. You can see some examples of when
parasympathetic and sympathetic nerves can be activated in the slide but you don’t have to remember all the details yet - we will come back
to this when we talk about regulation of heart function in more details.
What factors affect stroke volume
SV = EDV-ESV
• Increase in EDV
increases SV
• Decrease in EDV
decreases SV
• Increase in ESV
decreases SV
• Decrease in ESV
increases SV
We mentioned that cardiac output (amount of blood pumped through the heart in a minute) depends on stroke volume and this slides defines
stroke volume and how it can be affected. First of all, stroke volume is end diastolic volume minus the end systolic volume or on other words
how much blood enters the heart before the cardiac cycle and how much is left in the heart at the end of the cardiac cycle. The higher the
EDV (more blood enters the heart), the higher the stroke volume. The lower the amount of blood left in the heart (ESV), the higher the stroke
volume.
EDV depends on preload, which is how fast and how much venous blood is returning to the heart (more blood or faster return increases EDV,
thus increasing SV). ESV depends on resistance too flow (after load) and contractility of the heart . The higher the resistance or afterload, the
more blood is left in the heart or higher the ESV, which therefore reduces SV. The higher the contractility, the less blood stays in the heart so
the ESV is lower, meaning that SV is higher.
The bottom row of this table discusses regulation of cardiac output,
How do HR & SV affect cardiac output?
HR affected by
autonomic
innervation,
hormones and
input by venous
return
• SV affected by
preload,
contractility, and
afterload
• CO affected by
HR and SV
his slide summarizes how heart rate and stroke volume affect cardiac output again.
Heart rate is affected by autonomic regulation and hormones as seen on Slide 19. Factors that affect stroke volume (SV) are venous return
and filling time of the atria (which is related to preload). If venous return is large and filling time is fast, preload is high and therefore end
diastolic volume (EDV) is high. Because SV is EDV mini end systolic volume (ESV), when EDV is increased so is SV. Autonomic innervation,
hormones affect the contracitility of the heart. The higher the contractility, the less blood stays in the heart so the ESV is lower, meaning that
SV is higher. How vasodilated or vasoconstricted vessels are affects the resistance (afterload). The higher the resistance or afterload, the more
blood is left in the heart or higher the ESV, which therefore reduces SV. We will come back to in Module 4 in more details when we discuss
regulation of heart function.
Blood flow
Pulmonary: carries blood from and to gas exchange areas in lungs
Systemic: carries blood from and to areas of the body (other than the lungs)
Blood enters left atrium, left ventricle, rest of body
Right side from systemic circuit to right atrium, right ventricle to pulmonary
Pulmonary carries blood to and from gas exchange areas in lungs- capillary beds surround respite ray strictures
Blood leaving left atrium via aorta into smaller arteries
Through capillaries to exchange oxygen, nutrients collect waste, sent back to heart
Blood sent to systemic circuit first goes back through pulmonary circuit before sent to heart
More complex circuits, has communication with heart receives material from blood removes waste- hepatic
What are the major structures
Aorta vs artery
Lecture
The heart and two circuits
Pulmonary- lung and circuit that exists around alveola
Communication of heart to lung
Colouration of the blood, blue- deoxygenated, red- oxygen-
The space is capillaries
Two circuits dependent on one another blood reaching systemic goes through pulmonary before – need it to be oxygenated
One more type of system- hepatic
The liver receives and sends blood by systemic circuits, liver is connected to blood around different systems to help liver, receives from hepatic artery rom systemic and organs via hepatic veins important to regulation of hormones
What are arteries
Away from the heart
Elastic
Thick walls with small lumens
Three tissue layers, tunics:
intima, wavy, with elastic membrane in larger arteries media, thick, muscular, with elastic membrane in larger arteries
externa, thin in all but largest arteries, with elastic fibers and nerves
A- away from heart
Arteries carry blood away from heart
Elastic with thick walls
Lumen- space in blood vessel
Larger artery different from elastic
Creates pressure- larger ones
Three tissue layers- tunic
Intima- closest to lumen, wavy wide, elastic membranes
Media- thick elastic ape range, wav, most smooth muscle sport
External- most outer, thin, elastic fiber, nerve endings
Lecture
‘
Arteries- away from heart
Elastic and muscular- bigger
Aorta, artery
Return back to original sgaoe wth ease
Have thick walls an small lumens
Darker pin– walls and layers of vessel, the space is the lumen- inside space
In histological- no colour difference between vein and artery
Tunica
Intima- inner thinnest layer, wavy, closest to lumen
Media layer, extensive in bigger arteries
External- outer layer – biggest layer in large arteries, gives signals if it is increasing or Dec in diameter
What are veins
Toward the heart Compliant Thin walls with large lumens Valves in limbs and inferior to the heart
Three tissue layers, tunics:
intima, smooth, no elastic membrane media, thin, with collagenous fibers and nerves, no elastic membrane
externa, thick, with collagenous fibers, smooth fibers, smooth muscle and nerves
Carry blood toward heart
More compliant
Thin vessel wall, irregularly shaped, larger lumen
Medium- positioned inferior have valves correct blood flow
Tunic
Intima- thinner
Opposite direction of blood flow
Compliant- stretches easily, extends
Thinner walled, lumen is irregular shaped
Not wavy
Intima, smooth, no elastic membrane
Media- collagen
External- thickest, smooth muscle appearance
Venule- closest to capillary
Vein are resevoir of blood- 60%, processing more blood than arteries
Valves help push the blood flow towards the heart
What are capillaries
Continuous: water, small solutes and lipid- soluble material
Fenestrated: rapid exchange of water and large solutes peptides
Sinusoid (rarest): exchange of largest molecules (plasma, cells) in bone marrow, liver and glands
Other vessel
Capillary bed
Arteriole and venule empty into smaller vessels- capillary, network= bed
Have different openings in the layers
Sinusoid- many openings, let cell through support infiltration of cells, lymph glands
Continuous- small solutes fee started- middle
Have full membrane but can allow for rapid exchange of water and large solutes
Lecture
Mesh network- capillary bed- vessel circuits connect to cappilary on either side
Venule- receives from capillary
Filtration or exchange, here need higher chance for exchange, need to exhange many things- extra peatrive layers allow for molecules to go through
Most perforated , exchanges largest
How does diameter change in vessels?
Elastic arteries and venae cavae have the largest diametiencfralusdt(ecsdt.?losest
to the heart) Arterioles and venules have the
smallest diameter (closest to the capillary beds)
Different properties and factors of changes of blood vessels
They have different diamanter
Aorta and artery- larger so are veins
Higher diameter, more blood flow
Larger diameter, lower resistance
Increasing diameter Dec resistanxce
Lecture
Blood vessel types and diameter
Largest vessel, largest diameter
Order of vessel in closest to farthest from heart
Dimatater, directly proportional to blood flow, inversely related to resistance, higher diameter, lower resistance
How does area change in vessels?
Areas with vessels that have small diameter have the highestincfcalusdrteosdt.?ss-
sectional area Increase in cross- sectional area
increases surface available for exchange Cross sectional area
Area with vessels that have smal diameter have large area
What it to be larger so more elements can be exchanged through the tissues and body, not getting diameter , maximize space
Small diameter- highest area
Increases exhange of elements
How does velocity change in vessels?
Blood flows fastest in the
arteriesI with large diameter
Blood flows slowest in vessels with small diameters
High blood flow in the largest diameter
Connected to some of the layers lowest in small diameters
Veins have s larger diameter, why not as fast as arteries, they are more compliant and brings it toward heart, have harder time
As get closer to cappiliary want it to slow down, allows for exchange
High elastic pressure= artery
Venous- more compliance, less muscle
Artery work at higher speeds and pressures
Veins- don’t reach speed, more compliant and agianst gravity
How does velocity change in vessels?
There is a lot more blood
volumeI that needs to be supported
In large part, this blood volume needs to be circulated againts gravity
One-way valves to ensure unidirection al flow of blood (in limbs and vessels inferior to the heart)
The valves help the velocity inc, blood pushes through valve closes so there’s no backflip, helps push good up towards eart
Veins have more challenges, upport more blood volume
Artery can help take away
Blood needs to be circulated against gravity
One way vta;be help push blood up
Valves open one at a time, needs to pass through for valve to open first
How pressure changes in vessel
Pressure is the highest in arteries with the largest diameter and most elastic/muscular tunics
Pressure is the lowest in the largest veins
Blood pressure changes relates to large musculature tunic, thicker walled (muscular system veins
Related to resistance
Tunica media- thickest= highest power
How pressure changes
Blood pressure: peak systolic over peak diastolic
Arterial pressure is higher during ventricular systole (walls contract) and lower during diastole (walls stretch and recoil)
There is a pressure difference between the vessels, peace vessels in systole and lowest pressure in diastole
Arterial pressure is the average of the two contractile systems
Systolic- walls contracting
Lowest when diastole- walls of ventricles in stretch and recoil
Measuring this pressure- good presssure
Can help tell about heart health
Pressure during contraction and relaxation
Mean of presssure= average between relation and contraction
What happens in capillary beds
Bulk flow: fluid moves I from
pressure area (capillary bed) lower pressure area (tissues) via filtration
Net filtration pressure is the interaction of the hydrostatic (the force exerted by the blood in a vessel - forces fluids out of capillary) and osmotic pressures (the movement of fluid from the interstitial fluid - forces fluids into the capillary)
Filtration Hydrostatic pressure > osmotic pressure Positive net filtration (fluid exits capillary, filtration)
No net movement ydrostatic pressure = osmotic pressure
0 net filtration
(no fluid movements)
Reabsorption Hydrostatic pressure < osmotic pressure Negative net filtration (fluid enters capillary, reabsorption)
Surface area exchange and increase- exchange of blood and materials in tissue
Exchange in capillary beed
Fluid moves fom higher pressure(in blood vessel
To lower pressure area- tissue
Done via filtration
Can tell which direction it’s going out or in
Out- filtration
In- venous end- becomes venule drains into veins and back to heart
Return of the fluid- reabsorptiuon
Direction of bulk flow- can determine through the filtration pressure-NFP
Interaction of two pressures(hydrostatic- by blood vessel) osmotc(movement of fluid from interstitial fluid- moves back into capillary bed)
Higher pressure in capillary bed or higher osmotic pressure- positive net filtration- fluids moving from high to low, exiting capillary bed- filtration
Hydrostatic Lower than osmotic- negative net filtration
The fluid is moving bac- higher to lower pressure - reabsoprion
Equalized- zero movement
Bulk flow- fluid moves from high to low pressure via filtration
Hydrostatic- pressure in blood vessels
Osmotic pressure outside space
Are they moving from high to low- hydrostatic high and osmotic low- move from high to low
Hydrostatic pressure is low and osmotic is high, allows material into blood to be sent back
Different roles of blood
Cells, tissues, organs and organ systems of the body are impacted by or depend on the cardiovascular system
Delivering hormones
Transports white blood cells, antibodies and excess fluids from lymphatic
Transport for oxygen and carbon dioxide
Sexual arousal and erection, delivery of sex hormones
Delivers resting circulation to kidneys for filtering
Connections between blood and different body systems
These are the key riles
Major vessels- connect back to heart
Major pulmonary vessels
Pulmonary veins- right vs left- from and to lung
Aortic arch- ascending and descending aorta
Branches into 3 main arteries- brachiceohlaic trunk, common carotid artery
Most to left- subclavia atery’
Bring blood into right atriria
Right
Inferior and superior vena cava
Pulmonary trunk branches into pulmonary artery
Aortic arch
Coming from left atrium
You should be able to locate:
- aorta (ascending and descending)
- aortic arch
- vena cave (inferior and superior)
- pulmonary arteries (and pulmonary trunk - the base leaving the right
ventricle)
- pulmonary veins
Major systemic vessels
Brachiocephlaic branch
Scamming carotid artery descending aorta beach SES into ilia and femoral artery - into legs
Braciocheplaic trunk and sublavian, auxiliary artery connect to upper limb
Veins
Systemic veins bringing back to hart- right side
Brachiocephalic vein, axillary and cephalic vein
Iliac vein and femoral vein
Jugular vein]
Subclaviean
You should be able to locate:
- common carotid artery
- brachiocephalic trunk
- internal and external jugular vein
- subclavian artery and vein
- axillary vein and artery
- brachial artery and vein
- radial and ulnar artery and vein
- renal artery and vein
- iliac artery and vein
- femoral artery and vein
- tibial and fibular artery and vein
What is cardiac output
Amount of blood pumped by each ventricle in one minute
What does cardiac output depend on
Heart rate and stroke volume
We assess or measure cardiac function through cardiac output.
Specifically cardiac output (amount of blood pumped through the heart in
a minute) depends on heart rate and stroke volume. Heart rate is affected
by autonomic innervation, hormones (see Slide 4) as well as fitness level
and age
Heart rate
contractions per
minute or beats
per minute
• Affected by
sympathetic and
parasympathetic
innervation. Here you are seeing how heart rate is affected by autonomic innervation.
Vagus nerve has a parasympathetic signal to the heart to slow down the
heart rate, while the sympathetic cardiac nerves send a signal to increase
the heart rate. You can see some examples of when parasympathetic
and sympathetic nerves can be activated in the slide but you don’t have
to remember all the details yet - we will come back to this when we talk
about regulation of heart function in more details. We already discussed
the regular action potential signal through the conducting cells of the
heart.
Stroke volume
Stroke volume
(SV): how much
volume of blood
can the heart
pump
• SV = end-diastolic
volume (EDV) -
end-systolic
volume (ESV)
What does stroke volume depend on
Stroke volume (how much volume of blood can the heart pump) is
determined by heart size, fitness levels, gender, contractility of the heart
muscles, duration of contraction, how much blood did the heart receive
(preload) and how much resistance is there to sending blood out of the
heart (after load). You will discuss cardiac output in relation to exercise in
much more detail in next case study in tutorials (just before your first term
test).
What affects stroke volume
The higher the EDV (more blood enters the heart), the higher the stroke
volume. The lower the amount of blood left in the heart (ESV), the higher
the stroke volume. EDV depends on preload, which is how fast and how
much venous blood is returning to the heart (more blood or faster return
increases EDV, thus increasing SV). ESV depends on resistance too flow
(after load) and contractility of the heart . The higher the resistance or
afterload, the more blood is left in the heart or higher the ESV, which
therefore reduces SV. The higher the contractility, the less blood stays in
the heart so the ESV is lower, meaning that SV is higher
Increase in EDV increases SV
. Decrease in EDV =
decreases SV
• Increase in ESV decreases SV
• Decrease in ESV increases SV
How do HR & SV affect cardiac output?
• HR affected by autonomic innervation, hormones and input by venous return
• SV affected by preload, contractility, and afterload
The higher the EDV (more blood enters the heart), the higher the stroke
volume. The lower the amount of blood left in the heart (ESV), the higher
the stroke volume. EDV depends on preload, which is how fast and how
much venous blood is returning to the heart (more blood or faster return
increases EDV, thus increasing SV). ESV depends on resistance too flow
(after load) and contractility of the heart . The higher the resistance or
afterload, the more blood is left in the heart or higher the ESV, which
therefore reduces SV. The higher the contractility, the less blood stays in
the heart so the ESV is lower, meaning that SV is higher.
Neural regulation of heart rate
Parasympathetic nervous system; release of
acetylcholine; decreased levels of CO2, high
blood pressure; rest; decreased thyroid
hormones; decrease in calcium; increase in
sodium and/or potassium; decrease in body
temperature; opiates and depressants Sympathetic nervous system; release of
norepinephrine; increased levels of CO2, low
blood pressure; exercise or anticipation of
physical exercise; increased thyroid
hormones; decrease in sodium, potassium
and/or calcium; increase in body
temperature; stimulants (nicotine,
Here you are seeing how heart rate is affected by autonomic innervation.
Vagus nerve has a parasympathetic signal to the heart to slow down the
heart rate, while the sympathetic cardiac nerves send a signal to increase
the heart rate. You can see some examples of when parasympathetic
and sympathetic nerves can be activated in the slide but you don’t have
to remember all the details yet - we will come back to this when we talk
about regulation of heart function in more details.
Parasympathetic nervous system; release of acetylcholine; decreased
levels of CO2, high blood pressure; rest; decreased thyroid hormones;
decrease in calcium; increase in sodium and/or potassium; decrease in
body temperature; opiates and depressants.
Sympathetic nervous system; release of norepinephrine; increased levels
of CO2, low blood pressure; exercise or anticipation of physical exercise;
increased thyroid hormones; decrease in sodium, potassium and/or
calcium; increase in body temperature; stimulants (nicotine, caffeine)
Auto regulation of cardiovascular systems
Vascular resistance: friction between blood and vessel walls; depends on
diameter and length of vessel, ΔP represents the difference in pressure,
r4 is the radius (one-half of the diameter) of the vessel to the fourth
power, η is the Greek letter eta and represents the viscosity of the blood,
λ is the Greek letter lambda and represents the length of a blood vessel.
By examining this equation, you can see that there are only three
variables: viscosity, vessel length, and radius, since 8 and π are both
constants. The important thing to remember is this: Two of these
variables, viscosity and vessel length, will change slowly in the body. Only
one of these factors, the radius, can be changed rapidly by
vasoconstriction and vasodilation, thus dramatically impacting resistance
and flow. Resistance is inversely proportional to the radius of the blood
vessel and a slight increase or decrease in diameter causes a huge
decrease or increase in resistance. Most of the time and in the summary
diagram above, we are talking about arteriole vasoconstriction or
vasodilation but it does happen elsewhere, like in the veins.
Venoconstriction increases the return of blood to the heart or increases
the preload of the cardiac muscle
Neural regulation of cardiovascular systems
Neural mechanisms that regulate blood chemistry and pressure are:
sympathetic/parasympathatic innervation as well as overall radius of
peripheral vessels (vasconstriction/vasodilation)
Neural mechanisms
Blood pressure- cardiac centre, vasomotor centers
Sympathetic stimulation:
increasing cardiac output and increasing blood flow
Parasympathetic
sumulation. decreasing cardiac output and decreasing blood flow
Blood chemistry
Cardiac
Vasomotor centers
Vasoconstriction of most peripheral vessels - norepinephrine (NE):
decreasing flow, veins increasing flow
Vasodilation of select peripheral vessels - primarily acetylcholine
and nitric oxide (NO)
Increased blood pressure neural regulation
Inc blood pressure
Increased baroeexeptor firing
Increased inhibition
of cardiac and
decrease in activity
of accelerator and
vasomotor centres
Inc cardiac inhibitor centres
Lower cardiac accelerator centres
Decrease vasomotor centre
Decrease cardiac output HR and SV
(decrease in
venous return)
decreases CO
Inc vasodilation Increase in diameter
decreases resistance
Blood pressure drops
When blood pressure rises too high, the baroreceptors fire at a higher
rate and trigger parasympathetic stimulation of the heart. As a result,
cardiac output falls. Paraympathetic stimulation of the peripheral arterioles
will also decrease, resulting in vasodilation. Combined, these activities
cause blood pressure to fall.”
Blood Pressure (BP)=Cardiac Output (CO)×Peripheral Resistance
Here, peripheral resistance refers to the resistance the blood encounters as it flows through the arteries. If blood pressure increases and peripheral resistance remains constant, it may impact cardiac output.
DecreaSed blood pressure
Dec blood pressure
Dec baroreceptor firing
Dec cardiac inhibitors centers
Inc cardiac accelerators
Inc vasomotor centers
Inc cardiac output
Inc vasodilation
Blood pressure increase
When blood pressure decreases, the baroreceptors fire at a slower rate
and trigger sympathetic stimulation of the heart. As a result, cardiac
output rises Sympathetic stimulation of the peripheral arterioles will also
decrease, resulting in vasoconstriction. Combined, these activities cause
blood pressure to raise.”
Endocrine regulation of cardiovascular systems
Endocrine mechanisms that regulate blood volume and pressure are
related to hormones from renal, adrenal system, such as EPO, ADH,
Aldestorone and others help regulate the radius of peripheral vessels
(vasconstriction/vasodilation), which affects blood pressure and its
regulation
Endocrine regulation Dec blood pressure
For example, when blood pressure and blood volume is low, renin
(angiotensin II) and EPO secretion increases, which together increase
thirst and RBC formation, which together increase blood volume. Blood
volume increases while also sympathetic NS increases cardiac output
and peripheral vasoconstriction, which ultimately increases blood
pressure as well
Afterload
force the ventricles must develop to effectively pump blood against the resistance in the
vessels
Blood flow
movement of blood through a vessel, tissue, or organ that is usually expressed in terms of
volume per unit of time
Blood pressures
force exerted by the blood against the wall of a vessel or heart chamber; can be described with
the more generic term hydrostatic pressure
Cardiac output
cardiac output (CO)
amount of blood pumped by each ventricle during one minute; equals HR multiplied by SV
Cardiac plexus
cardiac plexus
paired complex network of nerve fibers near the base of the heart that receive sympathetic and
parasympathetic stimulations to regulate HR
Cardiac reflexes
cardiac reflexes
series of autonomic reflexes that enable the cardiovascular centers to regulate heart function
based upon sensory information from a variety of visceral sensors
End diastolic volume
also, preload) the amount of blood in the ventricles at the end of atrial systole just prior to
ventricular contraction
End systolic volume
amount of blood remaining in each ventricle following systole
Filling time
filling time
duration of ventricular diastole during which filling occurs
Heart rate
number of times the heart contracts (beats) per minute
Preload
also, end diastolic volume) amount of blood in the ventricles at the end of atrial systole just
prior to ventricular contraction
Stroke volume
stroke volume (SV)
amount of blood pumped by each ventricle per contraction; also, the difference between EDV
and ESV
Systolic pressure
larger number recorded when measuring arterial blood pressure; represents the maximum value
following ventricular contraction
Vasodilation
relaxation of the smooth muscle in the wall of a blood vessel, resulting in an increased vascular
diameter
Vasomotion
irregular, pulsating flow of blood through capillaries and related structures
Venous reserve
volume of blood contained within systemic veins in the integument, bone marrow, and liver that
can be returned to the heart for circulation, if needed
Aorta
largest artery in the body, originating from the left ventricle and descending to the abdominal
region where it bifurcates into the common iliac arteries at the level of the fourth lumbar
vertebra; arteries originating from the aorta distribute blood to virtually all tissues of the body
Aortic arch
arc that connects the ascending aorta to the descending aorta; ends at the intervertebral disk
between the fourth and fifth thoracic vertebrae
Arteriole
arteriole
(also, resistance vessel) very small artery that leads to a capillary
Artery
artery
blood vessel that conducts blood away from the heart; may be a conducting or distributing
vessel
Ascending aorta
initial portion of the aorta, rising from the left ventricle for a distance of approximately 5 cm
Axillary artery
axillary artery
continuation of the subclavian artery as it penetrates the body wall and enters the axillary
region; supplies blood to the region near the head of the humerus (humeral circumflex arteries);
the majority of the vessel continues into the brachium and becomes the brachial artery
Axillary vein
axillary vein
major vein in the axillary region; drains the upper limb and becomes the subclavian vein
blood colloidal osmotic pressure (BCOP)
blood colloidal osmotic pressure (BCOP)
pressure exerted by colloids suspended in blood within a vessel; a primary determinant is the
presence of plasma proteins
Blood flow
movement of blood through a vessel, tissue, or organ that is usually expressed in terms of
volume per unit of time
Blood hydrostatic pressure
force blood exerts against the walls of a blood vessel or heart chamber
Blood pressure
force exerted by the blood against the wall of a vessel or heart chamber; can be described with
the more generic term hydrostatic pressure
brachiocephalic artery
brachiocephalic artery
single vessel located on the right side of the body; the first vessel branching from the aortic
arch; gives rise to the right subclavian artery and the right common carotid artery; supplies
blood to the head, neck, upper limb, and wall of the thoracic region
brachiocephalic vein
brachiocephalic vein
one of a pair of veins that form from a fusion of the external and internal jugular veins and the
subclavian vein; subclavian, external and internal jugulars, vertebral, and internal thoracic veins
lead to it; drains the upper thoracic region and flows into the superior vena cava
Capillary.
capillary
smallest of blood vessels where physical exchange occurs between the blood and tissue cells
surrounded by interstitial fluid
Capillary bed
capillary bed
network of 10–100 capillaries connecting arterioles to venules
Common carotid artery
right common carotid artery arises from the brachiocephalic artery, and the left common carotid
arises from the aortic arch; gives rise to the external and internal carotid arteries; supplies the
respective sides of the head and neck
Common iliac artery
branch of the aorta that leads to the internal and external iliac arteries
Common iliac vein
one of a pair of veins that flows into the inferior vena cava at the level of L5; the left common
iliac vein drains the sacral region; divides into external and internal iliac veins near the inferior
portion of the sacroiliac joint
Compliance
degree to which a blood vessel can stretch as opposed to being rigid
Continuous capillary
most common type of capillary, found in virtually all tissues except epithelia and cartilage;
contains very small gaps in the endothelial lining that permit exchange
