Lecture 5: The Circulatory System Flashcards
Better to check the notes.
1
Q
What is the function of the heart?
A
The heart pumps blood through blood vessels to all parts of the body
2
Q
More specifically, the functions of the heart does two things:
A
1-delivers oxygen and nutrients to cells and tissues
2- Remove carbon dioxide CO2 and other waste products from cells and tissues
3
Q
What composes the heart wall ?
A
myocardium
4
Q
What is myocardium?
A
a layer of cardiac muscle forming the heart wall
5
Q
What type of muscle is the myocardium?
A
Cardiac muscle
6
Q
Why is the myocardium of the left ventricle so much thicker than that of the right ventricle?
A
It has to pump blood to your entire systemic circuit. So there’s enough force and pressure to send blood throughout your entire body.
7
Q
Is deoxygenated blood actually blue?
A
no
8
Q
Specialized cardiac muscle cells are part of which system of the heart?
A
intrinsic conduction system
9
Q
What does self-excitable mean?
A
Can contract without signals from the nervous system
10
Q
what do veins do?
A
They carry blood towards heart
11
Q
what do arteries do?
A
They carry blood away from heart
12
Q
Which parts of the heart are veins?
A
-Superior vena cava
-inferior vena cava
-pulmonary veins
13
Q
Which parts of the heart are arteries?
A
-pulmonary trunk
-aorta
14
Q
What is the function of atrioventricular valves?
A
To prevent blood flow from ventricle to atrium.
15
Q
What is the function of chordae tendinaea ( heart strings)?
A
help flaps to anchor themselves and remain closed
16
Q
What is the function of semilunar valves?
A
To prevent blood flow from arteries (aorta and pulmonary trunks)
17
Q
What makes the sound of your heartbeat?
A
the blood hitting against your valves
18
Q
What’s the name of the right atrioventricular valve?
A
tricuspid valve
19
Q
What’s the name of the left atrioventricular valve?
A
bicuspid valve
20
Q
Do av valve close or open when ventricles contract and relax?
A
they close when ventricles contract and open when ventricles relax
21
Q
Where do we find or what are the two types of semilunar valves?
A
pulmonary and aortic
22
Q
Do semilunar valves close or open when ventricles contract and relax?
A
opposite of av valves.
23
Q
what do av valves prevent?
A
the flow of blood from ventricle to atria
24
Q
what do semilunar valves prevent?
A
the flow of blood from arteries (pulmonary trunk and aorta) to ventricles
25
The heart is acting as two individual pumps: name them.
pulmonary (poumon) and systemic (système) circuit pump
26
True or False: Pulmonary and systemic circuits pump at alternate times.
False, they pump at the same time.
27
True or False: The blood flows through the pulmonary and not the systemic circuit with every heart beat.
False, pulmonary and systemic
28
What is right heart failure called? What is it?
peripheral congestion, fluid accumulation in the body tissues (more in the feet, ankles and fingers) and the build up of blood in the systemic circuit (congestion)
29
What is left heart failure? What is it?
pulmonary congestion, fluid accumulation and swelling in the lungs and back up (overflow) of blood in the lungs
30
What is the cardiac cycle?
1 complete heartbeat
31
what is systole?
heart contraction
32
what is diastole?
heart relaxation
33
Which part of the heart does most of the pumping work?
the ventricles
34
Explain the cardiac cycle.
1- atrial and ventricular diastole
2-atrial systole and ventricular diastole
3-atrial diastole and ventricular systole
-ventricles contract
-av valves closes
-semilunar valves open
-blood flow from ventricles into aorta and pulmonary trunk
35
What controls each heartbeat?
specialized self-excitable cardiac muscle cells that are part of the intrinsic conduction system of the heart.
36
what does self-excitable mean?
can contract without signals from the nervous system
37
true or false: cells of the cardiac conduction system have different intrinsic rates of contraction.
true
38
Why do we need the SA node?
Or else it will be out of sync. we need coordinated contractions. it sets the pace of the heart.
39
What's special about the SA node?
it has the highest rate of depolarization (muscle contraction) and sets the pace for the entire heart. It is the pacemaker.
40
Cardiac muscle cells are electrically coupled by______ (contain gap junctions) between adjacent cells
intercalated disks
41
what do gap junctions do?
they connect cytoplasm of 2 cells
42
What causes contractions?
Electrical impulses and depolarization of muscle cells
43
Why is it pausing at the AV node?
To make sure the atria have enough time to contract and to fully empty
44
How does an artificial pacemaker work?
Sends electric shocks to the heart
45
Why would someone need an artificial pacemaker?
If there is an issue with your pacemaker
46
What do implanted electrodes do?
send electrical impulses to cardiac muscle cells to regulate heart rate.
47
What are the factors that affect heart rate?(4)
1- two sets of nerves act on the SA node to increase or decrease heart rate.
2- hormones
3-body temperature
4- exercise
48
How does two sets of nerves affect HR?
1- sympathetic nerves= increase HR
2- parasympathetic nerves= decrease HR
49
How do hormones affect HR?
1-Epinephrine= increase HR
2- Thyroid hormones= increase HR
50
How does body temperature affect HR?
-High body temp= increase HR
-Low body temp= decrease in HR
51
How does exercises affect HR?
HR increases in response to exercise (increases metabolic needs to body)
52
What does ECG stand for?
| what is it?
Electrocardiogram (flow of electricity through heart)
53
True or False: Cells do not need to depolarize before they can be depolarized again
False
54
What is P-wave?
Depolarization of SA node and atria
55
What is QRS complex?
Ventricular depolarization
56
What is T-wave?
Ventricular repolarization
57
Where is atrial repolarization?
masked by QRS
58
Where does the AV node fire?
somewhere between P and Q
59
What is fibrillation or V-Fib?
| what causes it?
Lack of adequate blood supply to heart caused by myocardial infarction that can cause V-Fib, an uncontrolled shuddering of the heart, making the heart useless as a pump.
60
what stop fibrillation? How?
Defibrillators stop fibrillation by delivering an electric shock that "resets" the heart.
61
What do arteries do?
They carry blood away from heart (toward capillaries)
62
What do arteries branch into?
arterioles
63
what do veins do?
carry blood toward the heart (away from capillaries)
64
What converges into veins?
Venules
65
What are capillaries?
-site of exchange (blood-tissue; tissue-blood)
-upstream end branches from arterioles
-downstream end converges into venules
66
What are the three main layers of artery and veins?
1-Tunica intima
2-Tunica media
3-Tunica externa
67
What is the tunica intima composed of?
1-Endothelium (simple squamous epithelium)
2-Subendothelial layer
3- Internal elastic membrane
68
What is the tunica media composed of?
1- smooth muscle
2- elastic fibers
3- External elastic membrane
69
what is the tunica externa composed of?
1-collagen fibers (connective tissue)
2-Vasa vasorum
70
Why is the tunica media important?
Important for regulating the diameter of the vessel and supporting the pressure
71
capillaries consists only of which layer?
tunica intima
72
What differences do you notice between arteries and veins?
-The smooth muscle layer is much thicker in the artery than in the vessel
-The shape of the artery is circular while the veins don't have as much structure so they collapse more easily since less smooth muscle
73
Where does exchange with tissue happen?
In the capillaries (only)
74
What type of tissue lines the tunica intima?
the simple squamous epithelium
75
what does tunica intima do?
They minimizes resistance to blood flow
76
what is the purpose of tunica media?
for strength, movement and elasticity
77
What is the purpose of tunica externa?
For support and protection
78
What is the difference between the arteries and veins in the lumen? what's the reason?
The lumen is larger in veins because of low peripheral resistance ( low pressure= easier to go to heart)
79
What is the difference between the arteries and veins in the tunica media? what's the reason?
The tunica media is thicker in the artery to withstand high pressure
80
What is the difference between the arteries and veins in the tunica externa? what's the reason?
The tunica externa is thicker veins to provide support since they don't have a thick layer of smooth muscle
81
What is the difference between the arteries and veins in the elastic lamina? what's the reason?
Elastic lamina is only found in arteries to withstand high pressure.
82
What is the difference between the arteries and veins in the valves? what's the reason?
Valves are only found in veins to facilitates return of blood to heart ( prevents back flow)
83
Does blood pressure decreases as blood travels away from the heart ventricles? Why?
yes, because it counteracts resistance
84
What does the contraction of skeletal muscles provides ?
a "milking" action to push blood back to the heart
85
Valves close to ensure what?
blood only moves in one direction (towards the heart)
86
Where does blood flow the slowest through? Why?
Slow flow in the capillaries to enhance exchange
87
How is blood pressure measured?
The hydrostatic force that blood exerts on the vessel walls.
The force pushing against the wall of the vessel walls.
88
What keeps blood moving?
The pressure gradient provides driving force from high pressure to low pressure.
89
Are we measuring venous or arterial blood pressure?
Arterial because we get valuable information since pressure is very present.
90
What's the normal blood pressure?
120/70-80 mm Hg
91
Systolic pressure is created by__?
ventricles contracted (high blood pressure)
92
diastolic pressure is created by__?
ventricles relaxed (low blood pressure)
93
What happens when blood pressure is too high?
could cause a stroke ( blood vessel damage)
94
What happens when blood pressure is too low?
lose consciousness (inadequate tissue perfusion)
95
What is used to measure blood pressure?
sphygmomanometer
96
where do you break the flow of blood?
in the brachial artery
97
How can heart rate be measured?
indirectly by measuring pulse
98
What is a pulse?
pulse is the rhythmic stretching of arteries caused by contraction of the ventricles
99
What causes the arteries to stretch?
peripheral resistance in arterioles
100
how does peripheral resistance in arterioles causes the arteries to stretch?
it impedes (prevent) blood from exiting the arteries
101
What are the four factors affecting blood pressure?
1- peripheral resistance
2-cardiac output
3- blood volume
4- vessel elasticity
102
what does peripheral resistance depends on?
blood viscosity
total blood vessel length
blood vessel diameter
103
what determines the diameter of the arterioles?
the vasocontriction/vasodilation of arterioles which is controlled by action of nerve impulses, hormones and other chemicals on the smooth muscle surrounding the vessels
104
what does nitric oxide do?
it causes vasodilation (it lowers blood pressure)
105
what does endothelin do?
it causes vasoconstriction (it increases blood pressure)
106
how does stress affect arterioles?
stress will cause vasoconstriction
107
what is the effect of cardiac output on blood pressure?
an increase of cardiac output= increases pressure
108
what is the effect of blood volume on blood pressure?
increase in blood volume= increase pressure
109
what is the effect of vessel elasticity on blood pressure?
less elasticity= higher pressure (ex: arteriosclerosis)
110
Cardiac output depends on 2 variables:___
1- stroke volume (volume of blood pumped out by ventricles during each contraction)
2- heart rate
111
how does stress affect blood pressure?
more stress= increase blood pressure
112
how can you exercise without passing out or having a stroke?
during exercise, increase in cardiac output and decrease in peripheral resistance.
113
If blood pressure is low in veins compared to arteries, how can venous return= cardiac output?
resistance of arterioles and capillaries dissipates (make disappear) the pressure generated by the pumping heart
114
What are the three factors that increase venous return?
1- skeletal muscle pump
2-Respiratory pump
3-Lumens of veins are wider than arteries
115
how does skeletal muscle pump increase venous return?
skeletal muscles and valves provide a 'milking' action to keep blood moving towards the heart.
116
how does respiratory pump increase venous return?
When breathing, the thoracic cavity decreases and the pressure in vena cava and right atrium decreases
117
how does lumens of veins increase venous return?
wider= less resistance to flow/ low peripheral resistance
118
What also account for some movement of blood?
Rhythmic contractions of smooth muscle in the walls of veins and venules
119
What is the smallest blood vessels in the body?
capillaries
120
how much at any given time does you capillaries have blood flowing through them?
5-10%
121
which parts of the body are usually filled to capacity?
brain, liver capillaries, heart, kidney
122
Who controls the flow of blood through capillary beds?
constriction of arterioles and precapillary sphincters (rings of smooth muscle)
123
What would blood flow look like right after a meal?
more blood flow to digestive system
124
True or False: blood cells and proteins cross the capillary.
False, they are too large to cross (and should not)
124
How do molecules cross capillaries?
bulk flow through clefts between endothelial cells due to fluid pressure
125
What does the amount and direction of fluid flow depends on?
1- hydrostatic pressure: fluid pressing against wall (due to blood pressure) "pushing out"
2- osmotic pressure: non-diffusible plasma proteins pull water into capillary "sucking in"
126
how much do venous end reabsorb fluid?
85% of fluid is reabsorbed
127
Where does the remaining 15% of fluid go?
They are returned to the blood via the lymphatic system
128
What is the difference between the lymphatic and cardiovascular system?
lymphatic is not a circuit. It just cuts off in places. They intermingle amongst capillaries and vessels
129
how are fluids that leak from the capillaries into the ISF returned to the blood?
by the lymphatic system
130
what flows through a network of lymphatic vessels and has a composition similar to ISF?
Lymph
131
Where does the lymphatic system drain into?
the cardiovascular system via the subclavian veins.
132
How does fluid enter the lymphatic system?
by diffusing into lymphatic capillaries
133
In the lymphatic system, what do valves and skeletal muscle do?
valves= prevent back flow
skeletal; muscle= pushes fluid towards the heart
134
What are lymph nodes?
bean-shaped organs located at intervals along the lymphatic system ( filled with white blood cells)
135
What is the function of plasma?
it carries blood cells, cell fragments, nutrients, metabolic wastes, respiratory gases, and hormones around the body.
136
What is the composition of plasma?
1-90% water
2- Ions (electrolytes)
3- Plasma proteins
137
what do ions do?
-osmotic balance
-functioning of muscles and nervous system
-pH buffering
138
what do plasma proteins do?
-osmotic balance
-pH buffering
-viscosity of blood
-Transport of water insoluble lipids
-immunity (antibodies)
-blood clotting (ex: fibrinogen)
139
What is plasma without clotting factors called?
serum
140
What is the structure of erythrocytes?
-biconcave disc ( to increase surface area to transport and carry stuffs)
-no nuclei (more space for hemoglobin)
-no mitochondria
-contains 250 million molecules of hemoglobin
141
each hemoglobin is made of how many protein?
made of 4 polypeptides that can bind 4 molecules of O2.
142
what form part of the heme group? what does it bind?
iron atoms form part of the heme group that binds oxygen
143
what does hemoglobin bind?
oxygen and nitric oxide
144
what does nitric oxide cause?
it causes vasodilation which relaxes capillary walls to help delivery of O2 into cells
145
What are the functions of leukocytes?
1- effectors of the immune system (fight pathogens)
2- spend most of the time patrolling the interstitial fluid and lymphatic system
146
what do neutrophils and monocytes do?
they phagocytes that engulf and digest bacteria and cell debris
147
what do lymphocytes do?
develop into specialized B cells and T cells
148
What are basophils and eosinophils involved in?
they are involved in the allergic response
149
which white blood cells are part of granulocytes?
NEB
neutrophil, eosinophil, basophil
150
which white blood cells are part of agranulocytes?
LM
lymphocyte, Monocyte
151
what is the function of platelets?
blood clotting
152
How is clotting initiated?
when endothelium of a vessel is damaged and connective tissue in the wall is exposed to blood.
153
what is hemophilia? what does it cause?
An inherited defect in any step of the clotting process
causes excessive bleeding from even minor cuts and bruises
154
what causes spontaneous clotting?
platelets clump with fibrin within a blood vessel forming a thrombus
155
where are blood cells produced?
in bone marrow
156
where do all cells develop from?
pluripotent stem cells in the red marrow of bones
157
what is leukemia?
a type of blood cancer involving the elevated production of abnormal white blood cells.
158
what are the treatments of leukemia?
-to destroy a patient's bone marrow and replace it with bone marrow from a healthy person.
159
what is arteriosclerosis?
the thickening and hardening of an artery wall.
160
what is the process of atherosclerosis?
1- plaques develop in the inner wall of the artery
2- (plaque) formation is due to an inflammatory response that is initiated by deposition of lipoproteins in the vessel wall
3- the process takes several years and causes the vessel to narrow down and harden
4-plaques can rupture and promote the formation of a thrombus
161
what are the risk factors of atherosclerosis?
1- hypertension
2- LDL decrease and HDL increase
162
what is a heart attack?
the death of cardiac muscle tissue caused by prolonged blockage of one or more coronary arteries
163
what is a stroke?
the death of nervous tissue in the brain caused by the blockage of an artery or a leaking/burst blood vessel in the brain
164
In both a heart attack and stroke tissue dies due to lack of _____.
oxygen
165
what is angina pectoris?
If a coronary artery is partially blocked, a person may feel occasional chest pain because part of the heart is not receiving enough blood.
166
What substance forms a mesh to trap RBCs and platelets in the clotting process?
Fibrin
167
what is the main characteristic of hemophilia?
excessive bleeding
168
what prevents spontaneous clotting?
anticlotting factors
