The Cardiovascular System Flashcards
Which system consists of the heart and blood vessels?
the cardiovascular system
Which system consist of the heart, blood vessels, AND the blood?
the circulatory system
List the vague series of steps that describes the cirulation of fluid around the body.
1) bloodstream
2) tissue fluid
3) lymphatic vessels
4) bloodstream
Introduction
Which system can be included with the circulatory system besides the cardiovascular system?
the lymphatic system
Which system consists of the blood and blood-forming tissues?
the hematologic system
The heart lies within a thick partition called the ____ between the two lungs.
mediastinum
(meh-dee-uh-sten-uhm)
What are all structures which are housed in the mediastinum?
- heart
- esophagus
- trachea
- aorta
- other stuctures
What is the uppermost end of the heart called?
the broad base
What is the lower, bluntly pointed end of the heart called?
the apex
Which structure or organ does the apex of the heart rest just above?
the diaphram
Where does most of the heart lie in relation to the body’s medial plane?
left of the medial plane
What is the outermost layer of the heart called?
pericardial sac
Describe the pericardial sac and how it aids in the function of the heart.
It is a loose-fitting fibrous covering for the heart and it isolates it from other organs in the thoracic cavity. It also secretes lubricating pericardial fluid to allow the heart to beat with minimal friction. Finally, it prevents excessive expansion by giving the heart room to beat.
isolates, secretes pericardial fluid, and prevents excessive expansion
The heart consisted of ____ chambers seperated by ____ walls.
4; muscular
What are the two upper chambers of the heart called?
right and left atrium
Which chambers of the heart receive blood returing from circulation?
right and left atrium
What is the the thin muscular wall called that seperates the two atriums in the heart?
interatrial septum
What are the lower chambers of the heart called?
right and left ventricles
What isthe thick muscular wall called that seperates the right and left ventricles?
interventricular septum
What are the two valves called which control the flow of blood between the artium and ventricle?
atrioventricular valves
What are the flaps of atrioventricular valves called?
cusps
What is the right atriventricular valve called?
tricuspid valve
What is the left atrioventricular valve called?
bicuspid valve
it has 2 cusps
Which artery does the right ventricle pump blood through?
pulmonary trunk
Which artery does the left ventricle pump blood trhough?
aorta
Which valve regulates blood flow into the pulmonary trunk?
pulmonary valve
Which valve regulates blood flow into the aorta?
aortic valve
What is the upper vein which brings deoxygenated blood into the right ventricle of the heart?
vena cava
What is the purpose of valves in the heart?
It prevents backflow of blood in the heart. It ensures blood moves in a one-way fashion.
What are the three layers of the heart?
- epicardium
- myocardium
- endocardium
What is the external-most layer of the heart?
epicardium
What is the name and kind of epithelium that the epicardium consists of?
mesothelium; simple squamous epithelium
What is the physical appearance of the epicardium in some places?
it is thin and transparent
What are the two main components of the epicardium?
mesothelium and areolar tissue
When looking through the epicardium, there are some places where you can see through to the myocardium. When you cannot see through to the myocardium, which kind of tissue blocks your view?
thick deposits of adipose tissue
Because of the many deposits of adipose tissue, the heart is considered a rather ____ organ.
fatty
There are three major grooves on the surface of the heart. What is the overarching term for these grooves?
sulci
Which sulci of the heart encircles the base of the heart?
coronary sulcus
Which sulci of the heart decends the front of the heart as an oblique groove running towards the apex?
anterior interventricular sulcus
Which sulci of the heart cooresponds to the anterior interventricular sulcus?
posterior interventricular sulcus
Which kind of tissue is the most prevalent in the sulci (major grooves) of the heart?
adipose tissue
What structures does fat cusion in the sulci of the heart?
coronary arteries and nerves
What is the layer directly under the epicardium called which is composed of areolar tissue and adiposed tissue called?
subepicardial layer
What is the middle (and thickest) layer of the heart called?
myocardium
Which kind of muscle composes the myocardium and what is the primary cell which makes up this muscle?
cardiac muscle; cardiocytes AKA cardiomyocytes
What gives the myocardium its “stringy” look?
the cardiac muscle arranged in fasicles
The muscles contractions of the heart work in a ____ fashion.
rhythmic
What is the inner lining of the heart called?
endocardium
What are the structures within the heart that the endocardium forms a glossy surface layer for?
chambers and cusps of valves
What is the name and kind of epithelium that the endocardium consists of?
endothelium; simple squamous epithelium
What kind of tissue underlies the endothelium in the heart? What is this tissue layer sometimes referred to as?
areolar tissue; subendocardial layer
Which kind of fibers are unique to the endocardium, or subendocardial layer, of the heart ?
Purkinje fibers
What is the coiled pattern called in which the myocardial muscle fasicles form, spiraling towards the apex?
myocardial vortex
What does the twisting fashion of the heart do to the blood that is pumped from the heart?
it ensures an effective **ejection of blood **from the heart
Are cardiocytes in the musclar layers of the heart arranged in a fixed or sporatic orientation?
sporatic orientation
What are the regions of the heart wall which are composed of dense fibrous connective tissue?
cardiac skeleton
Which kind of connective tissue is the cardiac skeleton composed of?
dense fibrous connective tissue
The cardiac skeleton encircles the bases of the aorta and pulomary trunk in rings called what?
anuli fibrosi
“fibrous rings”
The cardiac skeleton archors valve cusps at patches called what?
trigonum fibrosum
The cardiac skeleton also forms the superior portion of the ____ septum.
interventricular
In terms of electrical signals, how does the cardiac skeleton located between the artria and ventricles help the heart function more efficiently?
The cardiac muscle prevents electrical signals from from traveling directly from atrial to ventricular muscle. It forces the signals to pass through defined pathways.
Some people have abnormal muscle bridges between the atria and ventricles. This causes the conduction pathway to be bypassed. What does this abnormality result in?
premature ventricular contractions (PVCs)
The cardiac skeleton is composed of dense irregular tissue in humans. What kind of tissue is the cardiac skelton composed of in sheep? What about cows?
- sheep - cartilage
- cows - osseous tissue
What does the structure of cardiocytes look like?
stubby “notched log” shape
What is the junction called where cardiocytes meet?
intercalated discs
Which structure do intercalated discs have that enhances the surface area of cell-cell contact?
fasciae adherentes (fascia adherens)
Which structure do intercalated discs have which mechanically link the cells to each other?
desmosomes
Which structure do intercalated discs have which allows the cells to communicate electrically?
gap junctions
What is it called when cardiocytes lose the ability to contract and instead generate and conduct electrical signals?
specialization (they become specialized)
Specialized cardiocytes constitute which two systems which coordinate the rhythmic contractions of the heart?
- pacemaker system
- cardiac conduction system
Which part of the electrical system of the heart is a small patch of cells located near the junction of the vena cava and the right artium?
sinoatrial (SA) node
“Pacemaker”
What is the signal speed of the SA node?
~1 m/s
The cells of the SA node spontaneously depolarize about ____ times per minute.
70
What is it called when the SA node initiates a wave of electrical current that passes from cell to cell through the two atria?
depolarization
How much of the ventricles are filled with passive blood before being “topped off” by pumped blood from the atrium?
two-thirds (2/3)
Which part of the electrical system of the heart is a small patch of cells located low in the right atrial wall just above the interventricular septum and to the right of the tricuspid valve?
atrioventricular (AV) node
What is the only route for an electrical signal to reach from the atria to the ventricle?
via the AV node
The AV node has narrow fibers that conduct electrical signal at ____ m/s, slowing down the signal for about ____ms.
0.05; 100
Which part of the electrical system of the heart is a cord of modified cardiocytes that arise from the AV node and penetrate into the interventricular septum?
In the septum, it lies just beneath the endocardium
atrioventricular bundle (bundle of His1)
What is the conduction speed of the atrioventrucular bundle?
4 m/s
The solidary AV bundle splits into right and left ____ ____.
bundle branches
The right and left bundle branches of the heart’s electrical system give rise to which kind of electrical fibers at the lower end of the septum?
Purkinje fibers
The electrical signals from Purkinje fibers travel from the ____ of the heart into the ____ ____ of the heart.
apex; ventricular walls
The region between the atrium and the ventricle is called the ____ ____.
coronary sulcus
The coronary sulcus is filled with fat and embeds which particular structures?
- artery
- vein
- coronary sinus
You are studying a slide of cardiac tissue which appears to have a cartilaginous cardiac skeleton. Which animal would you assume this cardiac tissue sample has been taken from?
a sheep
Which component of the circulatory system are tubular, mostly muscular organs for the transport and distribution of blood?
blood vessels
Which circuit of blood flow conducts blood only from the heart to the lungs?
pulmonary circuit
Which circuit of blood flow conducts from the heart to all parts of the body and then back again?
systemic circuit
Which circuit of blood flow only exchanges gases with inhaled air?
pulmonary circuit
What are the three main classes of vessels?
- arteries
- veins
- capillaries
Which kind of vessels conduct blood away from the heart and are subjected to the greatest stress from blood pressure?
arteries
efferent vessels
Which kind of tissue are larger arteries composed of?
elastic tissue
What are the smallest kind of arteries called?
arterioles
Which kind of vessels conduct blood to the heart and are subjected to least stress from blood pressure?
veins
afferent vessels
In tissue sections, veins generally look ____ due to their thin walls.
collapsed
irregular shapes
What are the smallest kind of veins called?
venules
What kind of vessels are microscopic and connect arteries and veins?
capillaries
What is the average length of a capillary, and what is their average diameter (in comparision to what it transports)?
- length - 1mm long
- diameter - the width of a red blood cell
Oxygenated blood presents a ____ color, while deoxygenated blood presents a ____ color.
red; red-violet
In the pulmonary circuit, arteries carry ____ blood to the lungs, and veins carry ____ blood back to the heart.
deoxygenated (blue); oxygenated (red)
In the systemic circuit, arteries carry ____ blood to the body, and veins carry ____ blood back to the heart.
oxygenated (red); deoxygenated (blue)
What are the three wall layers of arteries and veins?
- tunica intima (inner)
- tunica media (middle)
- tunica adventitia (outer)
Which layer of the vessel walls has a signal layer of squamous endothelial cells on a basement membrane with sparse subendothelial areolar tissue?
tunica intima
Which layer of the heart is the tunica intima continuous with?
endocardium
Which type of blood vessel is only composed of the tunica intima?
capillaries
Which layer of the vessel walls is a thicker middle layer of smooth muscle with elastic and collagenous fibers (something with an external elastic lamina)?
tunica media
Which layer of the vessel walls is the outermost layer, with a covering of loose connective tissue that often blends with neighboring organs such as veins and the esophagus?
tunica adventitia
In crowded areas such as the neck, various vessels, nerves, the esophagus, and the trachea, what do we called the surrounding loose connective tissue of the blood vessels?
tunica adventitia
Which kind of services do all blood vessels require for their tissues? How do they receive these requirements?
- nutrition, oxygenation, and waste-removal services
- smaller vessels which penetrate the tunica adventitia
What is the network of smaller vessels which service the larger ones called?
vasa vasorum
Which type of blood vessel is the vasa vasorum the most prominent in? Why do they require these extra nutrients?
veins; because they have a poor supply of glucose and oxygen
Which kind of nerves are found in blood vessels which help regulate their diameter?
sympathetic vasomotor nerves (SVNs)
What is the steady firing rate with allows blood vessel to maintain their state of partial constriction called?
vasomotor tone (VT)
For a vessel to dialte, it must first ____ its firing rate which ____ the smooth muscle.
lower; relaxes
Sympathetic vasomotor nerves (SVNs) only stimulate which layer of the vessel wall?
tunica media
Large (elastic, conducting) arteries include which major arteries in the body?
- pulmonary trunk
- pulmonary arteries
- aorta
- renal and iliac arteries
In large arteries and other vessels, what is a single sheet of elastic tissue which is penetrated with holes and forms a wavy boundary between the intima and media?
internal elastic lamina
The tunica media consists of 40-70 layers of elastic sheets called ____ membranes.
fenestrated
At the boundary between the tunica media and adventitia is wavy membrane called what?
elastic external lamina
Which kind of arteries are directed towards specific organs such as the spleen, liver, or stomach?
medium arteries
aka muscular or distributing arteries
Which size of blood vessel are a major point of resistence of blood flowing due to their size?
small arteries (resistence arteries)
Smallest are called arterioles
What are small resistence vessels which supply capillary beds called?
metarterioles
They have a precapillary sphincter
Which functions do capillaries provide that other large vessels cannot?
They provide nutirents, oxygen, hormone delivery, and waste removal
What is the typical diameter of a capillary?
5-10 micrometers
What is the typical diameter of a red blood cell?
7.5 micrometers
What is the speed of blood flow in the capillaries compared to that in the aorta?
- capillaries - 0.3 mm/s
- aorta - 320 mm/s
Why does blood flow slower in the capillaries (describe function as well)?
They have a much smaller diameter and this provides time for efficient O2 unloading and CO2 loading.
Although the capillary lacks a tunica media, it is often associated with satellite cells called ____.
pericytes
What are the three kinds of capillaries?
- continuous capillaries
- fenstrated capaillaries
- sinusoids
Which kind of capillary have an uninterrupted, tube-like, wall?
continuous capillaries
some have intercellular clefts
Which kind of capillaries are formed from endothelial cells that have patches of filtration pores?
fenestrated capillaries
In what organs are fenestrated capillaries commonly found?
small intestine, pancreas, endocrine glands, and kidneys
secretion and absorption organs
Which kind of capillaries are irregularly-shaped and conform to the shape left between surrounding cells of an organ?
sinusoids
Where are sinusoids typicslly found?
bone marrow, liver, spleen, lymph nodes, and some endocrine glands
What secretions do sinusoids help secrete from the liver?
albumin, globulins, and fibrinogen
How much of the bodies blood is contained in veins?
70%
What is the term for small veins and what is their tunica media mainly composed of (postcapillary and larger ones)?
venules
postcapillary - pericytes
larger venules - muscular
Postcapillary venues are the main site for which important function?
leukoycyte emigration
What is the tunica media of medium veins composed of?
muscle, collagen, and fibroblasts
What is the tunica adventitia composed of in medium veins?
few bundles of smooth muscle
What do some medium veins have which helps with the flow of bloof back to the heart?
valves
Which type of protein fibers are located in the tunica media of large veins?
collagen fibers
Describe the most common circulatory route.
blood passes through one capillary bed
Describe the portal system circulatory route.
blood passes trough two capillary beds in a series
Describe the arteriovenous anastomosis (shunt) circulatory route.
blood bypasses capillaries and flows directly from artery to vein
Describe the arterial anastomoses circulatory route.
blood flows from one artery to the next before reaching the capillary bed
Describe the venous anastomoses circulatory route.
blood flows from one vein to the next after leaving the capillary bed