Week 5 - Blood Vessels And Blood Pressure Flashcards
Name the main arteries in the body
- common carotid artery (right and left)
- subclavian artery (left and right)
- brachial artery (right and left)
- abdominal aortic artery
- radial artery (right and left)
- ulnar artery (right and left)
- femoral artery (left and right)
- popliteal artery (right and left)
- posterior tibialis (right and left)
- dorsalis pedis (left and right
What are the two arteries in the leg which are commonly palpated to assess blood supply to the lower leg?
- dorsalis pedis
- posterior tibialis
What are the smaller blood vessels in the body?
Capillaries
What are the blood vessels which are the primary site of vascular resistance (and therefore have the greatest role in blood pressure regulation)
Arterioles
Which blood vessel are notable for the large analyst of vascular smooth muscle in their walls?
Arterioles
Stimulation by the sympathetic nervous system causes the arterioles to what?
Constrict
True or false: veins have a thinner wall compared to arteries
True
What do veins contain which help to overcome the effects of gravity and assist in venous return?
Valves
Is the volume of blood in veins greater or smaller than the volume of blood in arteries?
Greater
Where are varicose veins most likely to form?
In superficial veins
What are the three veins in the arm commonly used for blood sampling and laboratory testing
- Medial cubital
- Cephalic
- Basilic
Describe the direction of blood flow from the heart using blood vessels and in order
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
Define cardiac output
The amount of blood pumped out by one ventricle (usually the left) in one minute
Define stroke volume
The amount of blood pumped out by one ventricle (usually the left) in one contraction
Define heart rate
The number of times the heart beats over one minute
If a patient loses a lot of blood and the blood pressure falls, it is due to …
Hypovolaemia
During hypovolaemia, the following responses happen:
The veins __ therefore __ the amount of blood returning to the heart (venous return and cardiac preload). The arterioles ___ causing an ___ in peripheral resistance (or peripheral vascular resistance). The heart rate and stroke volume will also ___ to ___ cardiac output
- Constrict
- Increasing
- Constrict
- Increase
- Increase
- Increase
What type of receptors (and their location) help to lower the blood pressure?
- Baroreceptors
- in the aortic arch and carotid arteries/bodies
What type of receptors (and their location) help to raise blood pressure?
- Baroreceptors
- in the aortic arch and carotid arteries/bodies
What control centre (and its location) controls the fall in blood pressure?
- The cardiac and Vasomotor centres (cardiovascular)
- in the medulla oblongata
What control centre (and its location) helps to raise the blood pressure?
- cardiac and vasomotor centres (cardiovascular)
- medulla oblongata
What type of effectors help to lower the blood pressure
Cardiac = myocardium and the SA node Vasomotor = vascular smooth muscle
What type of effectors help to raise the blood pressure?
Cardiac = myocardium and SA node Vasomotor = vascular smooth muscle
What is the body’s response to the fall in blood pressure?
- increased heart rate and contractility
- increased venous return
- increased PVR (pulmonary vascular resistance)
What is the body’s response to a rise in blood pressure?
- decreased Heart rate and contractility
- decreased venous return
- decreased PVR (pulmonary vascular resistance)
What is blood pressure?
The force blood exerts on the artery wall
What does blood pressure reflect?
- how compliant the arteries are
- the volume of blood forced into them
What are the functions of blood pressure?
- blood pressure pushes blood through blood vessels
- filtration of blood in the kidneys
- drives capillary exchange between blood and cells (gas exchange)
What is Systolic BP?
Relating to the phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries
What is diastolic BP?
Relating to the phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood
What is the mean arterial pressure?
It’s a calculation to check if there is enough blood flow, resistance and pressure to supply blood to all of the major organs
Normal BP for a healthy adult?
120/80
What are some lifestyle factors that influence BP?
- diet
- exercise
- vaping/cigarettes
- body weight
What are some genetic factors that influence BP?
Family history of cardiac disease
What are some factors which influence blood pressure?
- peripheral resistance
- blood vessel diameter — MOST IMPORTANT
- blood viscosity
- blood vessel length
- cardiac output
What is the major influencer of peripheral resistance?
Arterioles
What is the equation to work out cardiac output?
CO = SV x HR
Cardiac output = stroke volume x heart rate
What is preload?
The amount of blood in the ventricle before it contracts, (known as end diastolic volume)
What is after load?
The resistance that ventricles must overcome to circulate blood
What is contractility?
How strongly the ventricle can contract
What are the 3 factors that affect stroke volume?
- preload
- after load
- contractility
What are the 2 centres involved in the cardiovascular centre?
- cardiac centre
- Vasomotor centre
What does the cardiac centre do?
Located in the medulla oblongata, it controls the rate and force of the heart contraction
What does the Vasomotor centre do?
Located in the medulla oblongata, it controls the diameter of arterioles
When is adrenaline and noradrenaline released?
In emergency situations
What is the role of adrenaline and noradrenaline?
They are hormones which enhance the response of the sympathetic nervous system
How does adrenaline and noradrenaline raise blood pressure?
- increasing heart rate and force of contraction
- constricting many arterioles
- increasing venous pressure
How does the renal system play a part in blood pressure?
The kidneys control blood volume by increasing urine output when blood volume is higher
What are Age related changes to the cardiovascular system?
- Decreases compliance of the aorta
- Loss of cardiac muscle size and strength (decreases cardiac output)
- Increase in systolic BP
- Increase in total blood cholesterol
- Increase in coronary artery disease (major cause of death)
- Congestive heart failure (impaired pumping of heart)
- Atherosclerosis damage to blood vessels deduces blood supply to brain and kidney
Where do arteries carry blood?
Away from the heart
Role of capillaries
- Site of nutrient and gas exchange
- carry blood from arterioles to venules
- have very thin walls which is ideal for diffusion
Where do veins carry blood?
Towards the heart
The structure of blood vessels
- hallow interior called Lumen
- tunica intima (inner layer of wall)
- tunica media (middle layer)
- tunica external (outer layer)
Role of tunica intima
- Smooth texture to reduce friction
- lined by endothelium
Role of tunica media
- composed of smooth muscle & elastic fibres
- circular smooth muscle vasodilates and vasoconstricts to change the diameter of vessels
Role of tunica externa
It has:
- network of collagen fibres to protect and reinforce the vessel & anchor it to surrounding structures
- nerve fibres
- elastic fibres in larger vessels
2 types of arteries are..
- elastic
- muscular
Structure of elastic arteries
- large Lumen which is low resistance to blood flow
- can stretch and recoil without causing damage to accommodate for high pressure (aorta)
Structure for muscular arteries
- carry blood to furthest destinations from heart
- smaller in diameter compared to elastic
- thicker wall made from smooth muscle (brachial artery)
Structure of veins
- act as blood reservoirs which can be drawn on when BP drops
- thin walls - but blood flowing through is at low pressure so there is minimal risk of bursting
- contain one-way valves
Name the Arterial pathway - systemic IN ORDER
- LV pumps blood into ascending aorta
- flows to arteries
- then arterioles
- then capillaries
- then to various tissues and organs of the body
Name the venous pathway - systemic IN ORDER
- blood flows out of organ via venules
- venules to vein
- drains to inferior vena cava and superior vena cava
- blood returned to right atrium
What is Peripheral vascular resistance?
The opposition to blood flow caused by friction between blood and the vessel wall
- most resistance is encountered in arterioles and capillaries in the peripherals
- peripheral resistance in arterioles helps to determine arterial blood pressure
What happens in pulmonary circulation?
- veins and venules carry oxygenated blood to the heart
- arteries and arterioles carry deoxygenated blood to the lungs
What happens in systemic circulation?
- Oxygenated blood carries by arteries and arterioles
- deoxygenated blood carries by veins and venules
What is the largest vein? And what is it’s purpose?
- superior and inferior vena cava
- receives deoxygenated blood from all areas superior to the diaphragm (except coronary circulation)
What is the Great saphenous vein used for?
- longest vein in body
- used to replace blocked arteries in the heart for heat bypass operations
3 main carotid arteries
- external carotid
- internal carotid
- temporal artery
Role of the external carotid
Supplies tissues of head
Role of the internal carotid
Supplies brain and eye
True or false: the capillaries have the ability to constrict and dilate?
False
Where do all the arteries of the systemic circulation branch from?
Aorta
What is the vein that returns blood from the head to the heart called?
Jugular
True or false: arteries always carry blood away from the heart
True
How would relocating a vein for the purpose of bypassing a partial blockage in the coronary arteries support a better functioning Heart?
It would construct detours around blocked coronary arteries and return oxygen-rich blood flow to the coronary arteries
True or false: smooth muscle is found in all parts of the vascular system except the capillaries
True
True or false: very large arteries are called sinuses
False
True or false: stimulation by the vagus nerve slows he heart rate
True
Peripheral resistance to blood flow comes about because of..
Friction between the blood cells and vessel walls
True or false: in order for all the cells of the body to survive, blood supplies to all cells must be equal
False
True or false: the vasomotor control mechanism regulates changes in the diameter of arteries
True
