Cardiovascular System Flashcards
(63 cards)
1
Q
4 Functions of the Cardiovascular System
A
- Nutrient and Waste Transport: blood transports absorbed nutrients to liver for processing, cells release waste products of metabolism into bloodstream
- O2 and CO2 Transport: cells need O2 for cellular respiration, O2 molecules diffuse into blood through walls of lungs
- Temperature Maintenance
- Hormone Circulation
2
Q
Which side of the heart does (oxygenated) blood enter?
A
The left side
3
Q
Which side of the heart does (deoxygenated) blood return to?
A
The right side
4
Q
Which side of the heart has thicker muscle and why?
A
The left side of the heart has thicker muscle as it has to pump the blood to all the cells of the body. The right side of the heart only has to pump blood the short distance to the lungs.
5
Q
How does the cardiovascular system function to maintain temperature?
A
- Blood distributes heat, helping to maintain a steady body temperature.
- Blood passes through networks of vessels that lie under the skin.
- Blood passing through these vessels releases heat and has a cooling effect.
6
Q
What does the hypothalamus do? (2)
A
- Monitors body temperature
- Stimulates regulatory processes to constrict or dilate blood vessels
7
Q
Cycle of Homeostasis:
Increased body temperature
A
- Stimulus: increased body temp, exercising/warm climate
- Blood warmer than hypothalamic set point
- Activates heat loss center in hypothalamus
- Sweat glands activated. They secrete perspiration which is vaporised by body heat, helping to cool the body.
- Skin blood vessels dilate, capillaries flush with warm blood, heat radiates from skin surface
- Body temp decreases, blood temp decreases, heat loss center in hypothalamus shuts off
- Homeostasis reached
8
Q
Cycle of Homeostasis:
Decreased body temperature
A
- Stimulus: decreased body temp, cold climate
- Blood cooler than hypothalamic set point
- Activates heat promoting center in hypothalamus
- Skin blood vessels constrict, blood diverted from skin capillaries and withdrawn to deeper tissues. This minimises overall heat loss from skin surface
- Skeletal muscles activated when more heat must be generated: shivering
- Body temp increases, blood temp rises, hypothalamus heat promoting center shuts off
- Homeostasis reached
9
Q
Definition of hormones
A
Chemical messengers that are produced in one place in the body and affect cells or tissues in another
10
Q
How does the circulatory system aid in hormone circulation
A
The circulatory system is the travel vessel within which hormones travel throughout the body, from their site of production to the target tissues.
11
Q
What is the pericardium
A
Double walled protective sac
12
Q
The two layers of the pericardium
A
- Parietal pericardium: superficial part
- Visceral pericardium: inner pericardium
13
Q
What is between the parietal pericardium and the visceral pericardium?
A
The pericardial fluid
14
Q
What does the pericardium protect the heart from (3)
A
- Physical knocks
- Shocks
- Infection
15
Q
The three layers of the heart wall
A
- Outer layer = epicardium or visceral pericardium
- Middle layer = myocardium (muscle)
- Inner layer = endocardium (in contact w the blood)
16
Q
What is the bicuspid valve also known as
A
Mitral valve
16
Q
Where are the bicuspid valve and tricuspid valve located
A
Between the atria and ventricles
17
Q
Where are the two semilunar valves located
A
In the arteries leaving the heart
18
Q
Describe how the blood vessels transport the blood
A
- Arteries carry blood away from the heart
- Into a network of capillaries
- The blood is forced through the capillaries, where gases, nutrients and metabolic wastes are exchanged between the blood and tissues
- Blood passes from the capillaries into venules
- A network of venules and larger veins collects the blood and brings it back to the heart
19
Q
Why are capillaries one cell thick
A
To allow molecules to diffuse freely
20
Q
Describe the aorta
A
The largest artery. It is the main vessel that carries blood from the heart to the body.
21
Q
The 3 layers of tissue that make up the artery walls
A
- Tunica interna
- Tunica media
- Tunica externa
22
Q
Describe the tunica interna
A
Endothelial cells in contact with the blood
23
Q
Describe the tunica media
A
Thick layer of elastic fibres and smooth muscle
24
Describe the tunica externa
Layer of **protective connective tissue**
25
How do arterioles control blood flow and blood pressure
Muscles tighten and relax in response to messages from nerves and hormones to control blood flow and pressure
26
Dilation of arteries
Decreases the resistance to blood flow and blood pressure falls
27
Constriction of arteries
Resistance to blood flow increases and blood pressure rises
28
What are arterioles the main site for
Blood pressure regulation
29
What happens as arterioles merge into capillaries
Their **diameter decreases** until they consist of a **layer of endothelium wrapped with a few smooth muscle cells**
30
What facilitates the diffusion of gases, nutrients and wastes in the capillaries
The **closeness between capillary wall and red blood cells** facilitates the diffusion of gases, nutrients and wastes.
31
What are venules
Small veins that collect blood from the capillary beds and bring it back to larger veins that carry blood back to heart
32
Why do veins not experience pulse pressures?
The force of the heartbeat is greatly diminished by the time blood reaches the veins
33
What is pulmonary circulation
a "loop" through the lungs where the blood is oxygenated
34
What is systemic circulation
a "loop" through the rest of the body to provide oxygenated blood
35
Which is the only vein to carry oxygenated blood
The pulmonary vein
36
Which valve does blood flow through from left atrium to left ventricle
Left atrioventricular valve (bicuspid valve)
37
Function of the atrioventricular valve
To prevent blood backflow to atrium
37
What is the valve that closes off the aorta from the left ventricle
Aortic semilunar valve
38
Function of the coronart arteries
Carry freshly oxygenated blood to the heart itself
39
What branches off from the arch of the aorta and what do they do
The **carotid arteries** branch off and bring blood back to networks of vessels in the neck and head
40
What arteries bring blood to the shoulders and arms
The subclavian arteries
41
Description of the circulatory pathway
* Blood leaves left ventricle via the aorta
* From aorta, the first arteries are the coronary arteries which supply oxygenated bood to the heart
* From arch of aorta, carotid arteries bring blood to networks of vessels in neck and head
* Subclavian arteries bring blood to shoulders and arms
* Aorta descends down trunk of body, arteries branching off to supply organs such as kidneys, liver and intestines
* Aorta divides into 2 major vessels at the lower back, the common iliac arteries, then travel to each leg in the femoral arteries
* Blood in arterial system returns to heart after flowing through capillaries and returns to the heart in the veins
* The 2 large veins that collect blood from systemic circulation are the superior vena cava (upper body) and the inferior vena cava (lower body)
* Deoxygenated blood flows into the right atrium, through to the right ventricle through the right atrioventricular valve (tricuspid valve)
* Right ventricle through the pulmonary semilunar valve, into the pulmonary artery, which brancges into arteries carrying deoxygenated blood to the lungs
* Blood then returns to left side of heart with oxygen and cleared of much CO2
42
What are the 2 major vessels the aorta divides into at the lower back
The common iliac arteries
43
What are the arteries in the legs called
Femoral arteries
44
What is the Sinoatrial node (SA node)
A cluster of specialised cardiac cells embedded in upper wall of the right atrium
45
Function of the SA node
* it regulates the contraction of the heart
* sends out impulses that initiate each heartbeat
* impulses by the SA node cause the left and right atria to contract simultaneously
* excites the atrioventricular (AV)
46
What is the AV node
A bundle of cardiac muscle cells located at the base of the atria
47
Function of the AV node
* Conducts the impulse to specialised muscle in the septum
48
What is the impulse conducting muscle in the septum called
The atrioventricular (AV) muscle
49
What do the branches of the AV bundle divide into
Conducting fibres called Purkinje fibres
50
Function of the Purkinje fibres
They initiate the contraction of all the cells of the right and left ventricles
51
What is the "lub" sound of the heartbeat caused by
The closing of the AV valve at the start of ventricular contraction
52
What is the "dub" sound of the heartbeat caused by
The closing of the pulmonary and aortic semilunar valves at the end of ventricular contraction
53
What can be heard if the valves dont work properly
A sloshing sound (heart murmer)
54
Definition of Blood Pressure
The force exerted by blood on blood vessels
55
Normal blood pressure
less than 120mm Hg over 80mm Hg
56
What may an ECG (electrocardiogram) identify
1. Erratic heartbeats
2. Arrhythmias
57
What is the P wave on an ECG
COntraction of the atria
58
What is the QRS wave on the ECG
Contraction of the ventricles
59
What is the T wave in an ECG
Caused by electrical changes that precede the relaxation of the ventricles
60
What is end stage heart failure
A disease in which the heart muscle is failing severely in its attempt to pump blood through the body
61
What is zenotransplantation
A future possibility of being able to take a patients stem cells, manipulate them into cardiac cells and grow a heart that will start contracting after electrical impulse is applied
