Chapter 11.1 - Circulatory System Flashcards
What kind of circulatory systems do invertebrates have?
Can have no circulatory system, or open or closed circulatory system
Which organisms do not have a circulatory system?
Archaea, eubacteria, Protista, Fungi, Porifera, Cnidaria, Platyhelminthes, Nematoda, Rotifera
Organisms that do not have a circulatory system rely on:
simple diffusion
True or false: Insects pump blood through a central heart
False - pump hemolymph through several tubular hearts in dorsal vessel
Describe insect hemolymph flow
dorsal vessel -> sinuses -> hemocoel -> ostia -> back to dorsal vessel
What is hemolymph?
fluid that contains nutrients, lies between cells
Hemolymph moves around hemocoel via:
muscular contractions and locomotion
Insects have ___ located all over their body, and its function is:
spiracles; allow air to pass into the tracheal system thus allowing for gas exchange
Invertebrate animals with open circulatory system:
Mollusca, Arthropoda, Echinodermata
The most complex invertebrates have:
closed circulatory systems
Invertebrates with closed circulatory systems
Annelida (segmented worms)
Closed circulatory system includes:
blood, pumping heart, blood vessels
Annelids have multiple hearts called
aortic arches. they pump blood in a circuit
In annelids, blood moves to the front of the worm via ____ and to the back via ____
dorsal vessel; ventral vessel
Primary/true heart chambers include:
atria and ventricles
two chambered hearts have __ primary chambers:
2; single atrium and ventricle
Two-chambered hearts work well for:
fish (chordates that live in water)
true or false: atria are stronger than ventricles
false - ventricles are stronger than atria, they pump blood out to the rest of the body
In addition to two-chamberd hearts, fish also have:
secondary heart chambers
Function of secondary heart chambers
help primary chambers receive and pump blood
two-chambered hearts only pump ____ blood and they are:
oxygen poor; single circulation hearts (blood only travels through one circuit)
Three-chambered hearts have __ primary chambers:
3; one right atrium, one left atrium, and one ventricle
Three-chambered hearts are found in:
amphibians and non-avian reptiles
amphibians and non-avian reptiles are ___ ___
poikilothermic chordates
___ ___ have internal temperatures that fluctuate in response to the environmental temperature
poikilothermic chordates
Which reptiles have 4-chambered hearts?
alligators and crocodiles
3-chambered hearts mix ___ and ____ in the ___
oxygen poor and oxygen rich; ventricle
True or false: 3-chambered hearts are known as single circulation hearts
false - double circulation hearts, blood travels through two circuits
4-chambered hearts have _ primary chamberes:
left/right atria, left/right ventricles
4-chambered hearts are found in:
humans and birds
humans and birds are known as:
homeothermic chordates
4-chambered hearts are ____ circulation hearts. Does oxygen-poor and -rich blood mix?
double; no, since there are 2 separate ventricles
Atrioventricular valves prevent:
backflow of blood from the ventricles into the atria
The right AV valve is known as the:
tricuspid valve (since it has 3 cusps)
AV valves are attached to ____ via stringy tendons called the ___ ___
papillary muscles; chordae tendineae
Papillary muscles ___ to close the AV valves which prevents ____ during ventricular contraction
contract; inversion
The right ventricle pumps ____ blood through the _____ and into the ___ arteries
oxygen-poor; pulmonary semilunar valve; pulmonary arteries
The left atrium accepts ___ blood returning from the lungs via the ____
oxygen-rich; pulmonary veins
When the left atrium contracts, it pumps blood through the ___ valve and into the ____
mitral/bicuspid valve (AV valve); left ventricle
Left ventricle is the most:
muscular chamber of the heart
Left ventricle ejects ___ blood through the ___ valve and into the ___
oxygen-rich; aortic semilunar valve; aorta
___ has the highest blood pressure of any vessel
aorta
___ circulation has a higher resistance to blood flow than the ___ ___ even though the amount of blood pumped is the same
systemic; pulmonary (due to the fact that there are more vessels to perfuse)
Heart pumps blood to itself via ___ ___
coronary circulation
Coronary circulation begins when:
coronary arteries branch off the aorta and provide oxygen-rich blood to the heart’s myocardium.
myocardium
muscular layer of the heart
myocardium contains:
cardiomyocytes
___ ___ line the inside of the heart’s four chambers, forming a layer called the _____
endothelial cells; encocardium
___ ___drain oxygen-poor blood from the myocardium into the ____ ___ via the ___ ___
cardiac veins; right atrium; coronary sinus
___ ___ is a small opening in the right atrium
coronary sinus
The heart is protected by:
a multilayered pericardium
Pericardium is:
a sack of fluid surrounding the heart
The fluid in the pericardium is called:
serous pericardium
Serous pericardium is made of ___, which act as:
proteins; lubricant for the heart and reduces friction as the heart beats
All cardiomyocytes have a property called:
automaticity
Automaticity means:
action potentials are generated in cardiomyocytes without external nerves having to initiate the action potential
___ is the pacemaker of the heart and is located in:
SA node (sinoatrial node); right atrium
True or false: the heart can function completely independently
true, but still receives influence from the sympathetic/parasympathetic nervous system
Which nerve decreases heart rate?
vagus nerve
Which nerve increases heart rate and force of contraction?
sympathetic cardiac nerves
True or false: SA node wants to beat slowly
false - wants to beat quickly due to default quick automaticity
How is a heart rate of 60-90 bpm achieved?
parasympathetic vagus nerve extending from medulla oblongata innervates SA node causing it to slow down
tachycardic
heart rate above 100bpm
bradycardic
heart rate below 60 bpm
After the SA node reaches threshold:
sends a wave of depolarization through both atria, causing blood to be sent into the ventricles
When SA node’s wave reached the bottom of the right atrium, it will contact the:
AV node
AV node function
adds a brief delay in between the atria contracting and the contraction of the ventricles
If AV node was not present, what would happen?
atria and ventricles would contract at the same time, so ventricles would not be able to fill up quickly
AV node sends electrical signal to:
bundle of His in the interventricular septum
Bundle of His carries signal to the base of the heart via:
right and left bundle branches, then to Purkinje fibers
Purkinje fibers function
ensures coordinated contraction of both ventricles
Systole
occurs as the ventricles eject their blood into the arteries they connect to
In which phase of the cardiac cycle is blood pressure the highest?
Systole
Diastole
occurs right after the end of ventricular contraction. myocardium is completely relaxed
In which phase of the cardiac cycle is blood pressure the lowest?
diastole
Heart sounds
lub/dub
Lub
left and right atria are relaxed as the left and right ventricles are contraction
lub noise is due to:
ventricular contraction causing semilunar valves to open as the AV valves shut
Dub
left and right atria are contracting, which opens the AV valves so blood can fill the ventricles. semilunar valves are closed
Systole occurs between ___ while diastole occurs between ____
lub and dub; dub and the next lub
___ ___ are the contact points between adjacent cardiomyocytes that connect heart cells to each other
intercalated discs
intercalated discs contain:
desmosomes and gap junctions
desmosomes are:
small proteins that hold and adhere cardiomyocytes together
Gap junctions are:
protein tunnels that connect the cytoplasm of adjacent cardiomyocytes
gap junctions in the heart allow:
action potentials from one cell to go to the rest of the heart
connection of many heart cells together:
syncytium
First section of ECG
P wave, represents both atria depolarizing
Q wave of ECG
slight down wave before tall up wave
Q wave represents
depolarization through the interventricular septum, which initiates ventricular depolarization
tallest up wave of ECG
R wave - represents depolarization through ventricles
S wave of ECG
small down wave after R wave, completion of ventricular depolarization
T wave
medium up wave after QRS complex, ventricular repolarization
Repolarization of __ is hidden by the QRS complex
atria
Stroke volume
volume of blood pumped from the heart with each beat, generally refers to the left ventricle
true or false: both ventricles should pump equal volumes of blood
true
Stroke volume is calculated by:
subtracting end systolic volume from end diastolic volume
End systolic volume
amount of blood that remains in the ventricle following a ventricular contraction
end diastolic volume
amount of blood in the ventricle before a ventricular contraction
cardiac output
SV x HR. tells us the volume of blood being pumped by the heart in one minute
Total peripheral resistance
total amount of resistance that blood faces when flowing through the vasculature of the body
vasoconstriction
increases TPR
vasodilation
decreases TPR
systolic blood pressure refers to
the highest pressure in your arteries, which occurs when your ventricles contract during systole
SBP number
120
DBP number
80
diastolic blood pressure refers to
pressure in the arteries while the heart is relaxing between beats
Mean arterial pressure
average arterial pressure during one complete cardiac cycle
MAP is calculated as:
HR x SV x TPR
How can MAP be increased?
By increasing heart rate, stroke volume, or total peripheral resistance
tunica intima
directly surrounds the lumen of a blood vessel
tunica intima contains:
endothelial cells that reduce friction for blood flowing through the lumen
tunica media is located ___ and contains ___
directly above the tunica intima; contains smooth muscle cells that can be used to control the diameter of the vessel to manipulate blood flow
tunica externa is located ___ and contains ___
directly above the tunica media; contains collagen proteins that protect the vessel, nerve fibers and elastin proteins
most elastic vessels
arteries and arterioles
arteries elasticity comes from: (2)
- thick tunica media - smooth muscle can contract or relax, changes the diameter of the lumen in response to hormones.
- high amount of elastin protein in tunica externa allow walls of vessel to flex
___ branch off of arteries and have a ____ diameter
arterioles; smaller
___ are known as resistance vessels
arterioles
BP drops the most at:
arterioles
Which arteries carry OXYGEN POOR blood AWAY from the heart?
umbilical and pulmonary arteries
hormonal control of vasoconstriction/dilation mainly affects
arteries and arterioles
____ allows us to maintain our body temperature when it is cold
vasoconstriction
___ cools us down when it is hot by expanding the vessels
vasodilation
___ branch off of arterioles on one side and connect to venules on the other side
capillaries
How thick are capillaries?
one endothelial cell thick - only have a tunica intima
Capillaries have ___ that increase what can diffuse into and out of the capillary
fenestra
Function of capillaries
bring nutrients to cells in tissues, removes wastes
How do nutrients get dropped off to tissues?
hydrostatic pressure is high, arterial end of the capillary forces plasma out of the vessel
At the venous end of the capillary, wastes are:
pulled back into the capillary because osmotic pressure is high
___ are wider than arteries
veins (so they hold more blood)
Blood pressure is lowest once it has reached:
the veins
Veins contain:
valves to prevent backflow and ensure blood flows back to the heart
Veins rely on ___ and ___ to have adequate venous return to the heart
skeletal muscle pump and respiratory pump
Veins are known as
capacitance vessels
How does the skeletal muscle pump push blood through veins?
just by contracting/relaxing, pushes blood in 1 direction due to valves preventing backflow
respiratory pump
when you inhale, pressure in thoracic cavity decreases and increases in abdomen, squeezes veins in the area, which moves flood forward
hepatic portal vein shunts blood from
digestive tract to the liver
hypophyseal portal system
allows hormones from the hypothalamus to enter the anterior pituitary without having to travel to and pass through the heart,
clotting cascade is a ___ feedback mechanism
positive
Steps of clotting cascade
- tissue is damaged, exposes collagen in the wall
- platelet activation forms platelet plug
- activated platelets release thromboplastin which converts prothrombin to thrombin
- activated thrombin converts fibrinogen to fibrin, polymerize with other fibrin strands, attach to platelets to form blood clot
Important element in manufacture of clotting factors
Vitamin K
True or false: blood is not considered a tissue
false - it is a connective tissue
Blood volume is composed of:
plasma, leukocytes and platelets, RBC’s
What does blood plasma contain
water, proteins, hormones, other nutrients
platelets are:
anucleate cell fragments
precursor of platelets:
megakaryocytes (heavily involved in the clotting cascade)
what protein structure does hemoglobin have
quaternary
Each hemoglobin molecule can bind:
4 Oxygen molecules
If a person receives a transfusion of the wrong blood type:
immune system will mount a response that causes erythrocytes to agglutinate
Universal donor
O-
Universal acceptor
AB+
___ carries oxygen rich blood from the placenta to the fetus through the umbilical cord
umbilical vein
