Circulatory System Flashcards
(57 cards)
1
Q
Why do human bodies need circulation?
A
- our bodies need a way to transport nutrients to and away from cells
- because many cells do not have direct contact with the environment
- unlike amoeba (they are unicellular)
2
Q
What are the three functions of the circulatory system?
A
- transport gases, nutrient molecules, and wastes
- regulates internal temperature and transports hormones (homeostasis)
- protects against blood loss from injury and against disease-causing microbes or toxic substances
3
Q
What is the structure of the circulatory system?
A
- heart
- blood vessels
- blood (living tissue)
4
Q
What is the cardiovascular system?
A
- includes the heart and blood vessels
- A closed system
- blood remains contained in the vessels
- nutrients exchange through vessel walls
5
Q
What is the blood vessels function?
A
- The body’s transport system
6
Q
What are arteries?
A
- blood vessels that carry blood away from the heart
7
Q
What are veins?
A
- Blood vessels that carry blood towards the heart
8
Q
What is a common misconception about veins?
A
- veins carry deoxygenated blood
- this is false!!
9
Q
What are capillaries?
A
- tiny blood vessels that connect the arteries and veins
- gas and nutrient exchange occur here
10
Q
What is the structure of arteries? (5)
A
- elastic walls that can expand and snap back as blood is pumped away from the heart
- keep blood moving in the correct direction with this motion
- Smaller arteries are called arterioles
- thick walls
- Three layers
11
Q
What are the three layers of the artery walls?
A
- Connective (elastic) (outer)
- Muscular (elastic)
- Smooth (one cell thick, reducing friction)
12
Q
What is the structure of veins? (6)
A
- thinner walls than arteries
- larger inner diameter
- not as elastic as arteries and cannot contract
- muscle contractions in the body push blood through veins
- one-way valves keep blood moving in the correct direction
- Smaller veins are called venules
13
Q
What is the structure of capillaries? (5)
A
- walls are one cell thick
- Red blood cells pass-through through in single file (diameter is small)
- fine network for gas and nutrient exchange (large SA)
- most cells of the body are near capillaries, but not every cell (ex. Some fat cells)
- attached to arterioles and venules
14
Q
What are precapillary sphincters?
A
- rings of smooth muscle at the ends of arterioles that regulate blood flow into capillaries
- if all sphincters were open, there would not be enough blood in the body to fully fill all the capillaries at once
- hence they regulate blood flow to where it is needed
15
Q
What do arteries do in terms of providing blood?
A
- arteries that provide blood to the body from the heart and lungs, carry blood with much oxygen (oxygenated blood)
16
Q
What do veins do in terms of blood?
A
- veins that are returning blood from the body to the heart and lungs, carry blood with little oxygen (deoxygenated blood)
17
Q
How is the pulmonary circuit in the lungs an exception to arteries and veins?
A
- arteries carry deoxygenated blood, and veins carry oxygenated blood
18
Q
What is the function of the heart? (4)
A
- Pumps blood
- keeps oxygenated and deoxygenated blood separate
- ensures One Direction of blood flow in the body
- rhythmic and involuntary cardiac muscle contraction allow for pumping
19
Q
What is the heart’s structure? (5)
A
- left and right sides (left on diagram is right irl)
- four chambers [2 atria (singular: atrium) and 2 ventricles]
- left atrium on top left
- left ventricle on bottom left
- right atrium on top right and right ventricle on bottom right
20
Q
What do the atria do?
A
- receives blood from the body through the vena cavae, And lungs (pulmonary veins)
21
Q
What do ventricles do?
A
- receive blood from the atria
- pumps blood to the body through the aorta
- Pumps blood to the lungs through the pulmonary trunk and pulmonary arteries
22
Q
What separates the left and right side of the heart?
A
- muscular wall (septum)
23
Q
What is the purpose of heart valves? What are the type of valves?
A
- ensure blood flow in proper direction
- atrioventricular valves between the atria and ventricles
- semilunar valves between ventricles and arteries
24
Q
Where are the specific atrioventricular valves located?
A
Bicuspid (mitral valve) on left side of heart irl
- tricuspid on the right
25
Where are the specific semilunar valves located?
- aortic semi lunar on left site in real life
| - pulmonary semilunar on right
26
What is the epicardium?
- outside layer of the heart wall
| - Prevents it from adhering to surrounding structures
27
What is a pericardium?
- fibrous, protective, saclike structure surrounding heart
| - A fluid between epicardium and pericardium allows for frictionless movement of heart in sac
28
What is the myocardium?
- middle cardiac muscle layer of the heart
29
What is the endocardium?
- inner lining of the heart
| - It is smooth to avoid friction and lose energy
30
What are papillary muscles?
- Nipple shaped projections that extends from the floor of each ventricle
31
What are Chordae tendinae?
- thin, strong, connective tissue threads connecting the edges of valves to papillary muscles
- prevents AV valves from opening upward into the atria
(Anchors valves flaps so it does not invert up and blood goes wrong way)
32
What are the two main loops of pathways of circulation?
- Pulmonary pathway and systemic pathway
33
What is a pulmonary pathway of circulation?
- oxygen-poor blood pumped from heart to lungs, is oxygenated in the lungs, and returns to the heart
34
What is the systemic pathway of circulation?
- Oxygen-rich blood pumped from the heart to body, is deoxygenated, and returns to the heart
35
What is the coronary pathway of circulation?
- technically a systemic pathway
| - Blood vessel pathway that provide blood to the tissues of the heart itself
36
Describe the hepatic portal system
- Recall that proteins are transported to the liver by the bloodstream to be processed and distributed throughout the body
1. Small intestine absorbs products of digestion
2. Nutrient molecules travel in hepatic portal vein to liver
3. Liver monitors blood content
4. Blood enters general circulation by way of the hepatic veins, which empty into the inferior vena cava
37
What is your heart be controlled by?
- electrical signals from your nervous system from within the heart
38
What is the sinoatrial node, and how does it help in regulation of heartbeat?
- it is a pacemaker
- bundle of nerve fibers
- stimulates rhythmic contractions and relaxations of the heart
39
Explain the process in the Sinoatrial node function
- The SA node is in the right atrium wall
- Signal causes atria to contract (blood goes to ventricles)
- initiates contractions (strong contractions of ventricles)
- Signal reaches atrioventricular node
- AV Node transmits electrical signal through the bundle of His to two bundle branches to the Purkinje fibres
- purkinje fibres initiate simultaneous contraction of the ventricles
40
What is the electrocardiogram? ECG, EKG
- Records electrical activity of the heart during contractions and relaxation of the atria and ventricles (voltage changes)
41
What is a P wave in an ECG?
impulse prior to atrial contraction
42
What is the QRS wave in an ECG?
impulse prior to ventricular contraction
43
What is the T-wave in an ECG?
ventricle recovery
| - u wave recovery is not always seen
44
What sound does a heart make?
- as the heart pumps, we hear the “lubdub” sounds of heartbeat
45
Where does the “lub” sound come from?
-comes from the simultaneous closing of the bicuspid and tricuspid AV valves, as ventricular contraction occurs
46
Where does the “dub” sound come from?
Comes from the simultaneous closing of the pulmonary and aortic semilunar valves as the ventricles relax
- Note that when ventricles relax, they try sucking blood back in
47
What is blood pressure?
- Pressure exerted against blood vessel walls as circulating blood passes through vessels
- Measured in arteries because blood is forced by heart out very quickly
48
How does blood pressure change with ventricle contraction and relaxation?
ventricles contract: higher blood pressure
| Ventricles relax: lower b.p.
49
What is systolic pressure?
- Max blood pressure during ventricular contraction
50
What is diastolic pressure?
Lowest blood pressure before ventricular contraction
51
How is blood pressure measured?
- use a blood pressure cuff
- millimetres of mercury (mmHg); a pressure measurement
120/80 is systolic over diastolic
52
What is the resting blood pressure of an average healthy young person?
Below 120/80
53
How does homeostasis play a role in blood pressure?
- during exercise, heart rate increases, pushing a higher volume of blood in a unit of time
- this increases blood pressure during exercise
- receptors in vena cavae and right atrium detect increased venous pressure and send message to brain
- The brain sends a message to the heart to increase heart rate
54
How does heart rate decrease?
- receptors in aorta stimulated by high blood pressure send message to the brain that heart rate must be decreased
- receptors in carotid artery send message to decrease heart rate in response to blood pressure to brain being too high
55
How does the Vagus nerve control the heart?
- slows the pacemaker, resulting in a week Systole and prolonged diastole
56
How does the cardio-accelerator fibers control the heart?
- speed up the pacemaker
| - Results in increased heart rate and ventricular contraction
57
Where do the Vagus nerve and cardio- accelerator fibers originate from?
Medulla oblongata of the brain
