Cardiovascular System Flashcards
1
Q
The cardiovascular system can be divided into 2 parts. What are they?
A
- circulatory system: conists of heart and the blood vessels
- lymphatic system: consists of lymph nodes and lymph vessels.
2
Q
What are the three main functions of the circulatory system?
A
- transportation
- regulation
- protection
3
Q
what are the functions of transportation of the circulatory system?
A
- respiratory: transports o2 to the tissues and co2 back to lungs
- nutritive: absorbed digested products are transported back to liver and tissues
- excretory: waste produts from metabolism are transported to the kidneys for excretion in urine.
4
Q
What is the function of regulation in the circulatory system?
A
- hormonal: hormones are carried from the endocrine glands to their target tissues
- temp: the blood can be diverted to warm or cool the body.
5
Q
What are the functions of proetction in the circulatory system:
A
- clotting: blood contains platelets and can prevent blood loss through clotting
- immune: blood contains leucocytes (WBCs) and cytokines which protects against infective pathogens
6
Q
What are blood vessels?
A
- the inter-connected series of tubes whic carry blood from the heart to the organs and tissues and back again
- divided into 3 main groups: arteries, veins, capillaries
7
Q
What are arteries?
A
- transports blood away from the heart
- have thick walls to enable to withstand high pressure of arterial blood
- as they branch and become smaller they become arterioles e.g. aorta
8
Q
What are veins?
A
- return blood to the heart
- have thinner walls because blood is under low pressure
- some have valves whivch prevent backflow to it goes to the heart
- smallest veins are called venules e.g. vena cava
9
Q
What are the 3 layers of the blood vessel?
A
- tunic externa
- tunic media
- tunic intima
*capillaries only have the tunic intima
10
Q
What is the tunic externa?
A
- connective tissue
- outer structuaral wall of the vessel
- thickest layer in veins
11
Q
What is the tunic media?
A
- smooth muscle
- can be constricted to control diameter of lumen
- thickest layer in arteries
12
Q
What is the tunic intima?
A
- endothelium
- barrier between blood and vessel wall
- secretes vasoactive substances
- control permeability in capillaries
13
Q
What are the properties of the vein?
A
- carry blood back to the heart
- larger lumen
- lower pressure
- can be compressed
- semi lunar valves to prevent backflow
- can dilate and constrict to lesser extent to allow heat dissipation
14
Q
What are varicose veins?
A
- of the blood stagnates in the veins and clots
- it can develop into a varicose vein
-they can be surgically removed?
15
Q
What are capillaries?
A
- from a vast network of tiny vessels which link the smallest arterioles to the smallest venules
- small diameter
- consist of a single layer of endothelial cells which water and molecules can pass through
- capillary bed is the site of exchange of substances between the blood and tissue fluid which bathes body cells
16
Q
What are the properties of capillaries?
A
- link the artery to the veins
- one arteriole splits into 20-100 capillaries
- capillaries are the smallest of blood vessels
- only one cell thick (tunic imita only)
17
Q
The heart pumps blood into what 2 systems of blood vessels?
A
- pulmonary circulation
- systematic circulation
- the right side pumps blood to the lungs where gas exchange occurs
- the left side pumps blood into the systematic circulation which supplies the rest of the body.
18
Q
What are the properties of the heart?
A
- aorta
- pulmonary artery
- pulmonary vein
- left atrium
- left ventricle
- superior vena cava
- right atrium
- inferior vena cava
- right ventricle
- tricuspid valve
- myocardium
- bicuspid valve
- septum
- pulmonary valve
19
Q
blood flow through the heart
A
- deoxygenated blood from the body empties into the RA via inferior and supervior vena cava
- blood passes through the tricuspid into the RV
- from the RV the blood goes to the lungs via pulmonary artery
- blood picks up o2 in the lungs and excretes co2
- oxygenated blood returns to the LA via pulmonary veins
- flows into the LV through the mitral valve
- LV pumps blood to the body through the aorta and other arteries
20
Q
What are the 4 chambers of the heart?
A
- right atrium
- right ventricle
- left atrium
- left ventricle
21
Q
What is the septum of the heart?
A
seperates the 2 sides of the hearts
22
Q
What are the 3 layers of the heart?
A
- pericardium (outer layer)
- myocardium (middle layer)
- endocardium (inner layer)
23
Q
What are the 3 layers of the pericardium?
A
- fibrous pericardium: surrounds and anchors heart in place
- pericadium space: contains a lubricant which reduces friction as heart contracts
- viseral layer: attached to the heart surface
24
Q
What is the purpose of the pericardium?
A
- protects the heart from infection by enclosing it
- prevents the heart from over expanding
- prevents fiction via serous fluid in the pericardial activity
25
What is the purpose of the myocardium?
- heart muscle
- acts like a pump
26
What is the purpose of the endocardium?
- lines the chambers of the heart and forms the valves
- receives the blood supply from the coronary arteries.
27
What are the function of the valves?
- situated at the entrance and exit of the ventricles
- ensure that blood flow moves only in one direction --> forward
- blood flows through the valves as a result of pressure changes
28
The electrical system within the heart
- the heart has an intrinsic ability to beat without the need of a nerve supply from the brain
- there are specialised cells in the heart muscle which initiate and conduct impulses so that the heart contracts in a synchronised and co-oridanted way
29
What is the sinoatrial (SA) node?
- is a small mass of specialised cells in the wall of the right atrium
- known as the pace-maker of the heart
- generates an impulse which travels through the atria causing them to contract
30
What is the atrioventricular (AV) node?
- is a small mass of neuromuscular tissue in the wall of the atrial septum near the AV valves
- is resposnible for transmitting the nerve impulse from the atria to the ventricle
- can initate impulses itself but at a slower rate than the SA node
31
What is the Bundle of His?
- a mass of specialised fibres that originates in the AV node
- from the AV node the impulses travels down the BoH
- the bundle then branches off to the left and right side of the heart
- the 2 branches then break up into fine fibres called the purkinje fibres
- this impulse causes ventricular contraction
32
What is the cardiac cycle?
- sequence of events in 1 heartbeat
- during every heartbeat the heart contracts and then relaxes
- the period of contraction is called systole
- the period of relaxtion is called diastole
33
Blood supply to the heart
- the heart requires oxygen and nutrients to function
- the heart is supplied with blood from the right and left coronary arteries which branch off the aorta
- most blood is then returned to the right atrium via the coronary sinus
- ensures the myocardial cells are close to their blood supply.
34
Cardiac blood flow
- cardiac blood flow is different from blood flow in other organs
- blood flows around the coronary vessels during diastole
- myoglobin in mycardial cells stores oxygen
- this ensures that the heart muscle has a constant supply
35
What is the equation for cardiac output?
heart rate x stroke volume = cardiac output
36
What is blood pressure?
the measurement of force applied to the artery walls
37
38
What is the equation for blood pressure?
blood pressure= peripheral resistance x cardiac output
