what are the functions of the cv system
- Transport nutrients
- Remove waste products
- regulate body temp
- transport hormones
- transport immune cells for defence
- reproduce and provide nutrients to unborn foetus
name the 3 components of the cv system
Name the 4 divisions of the cv system
- Pulmonary system - heart to lungs
- systemic - heart to body cells
- hepatic portal - heart to liver, pancreas, digestive tract
- coronary - blood supply to heart muscles.
talk about the position of the heart
- Thoracic cavity
- infant of spine behind sternum
- Base is at the second rib
- Apex is at a 60 degree angle
- Apex is 9cm from sternum
- Apex is at the 5th intercostal space - mid clavicular line
What are the measurements of the heart
- 10cm long
- 9cm wide
- 6cm deep
how much does the heart weigh
Name the layers of the heart
- pericardium - fibrous and serous. parietal and visceral pericardium with serous fluid
- myocardium- its cardiac muscle tissue, which contains branching elongated cells which conduct own impulse called autorhythmicity.
- endocardium - inner layer - endothelial cells continuous with blood vessels.
What are the upper chambers made up of
Left and right atria
what are the lower chambers made up of
left and right ventricles
what separates the left and right atria
what separates the ventricles
where is the myocardium thickest
the left ventricle as it has to pump blood the furthest out of all the chambers
what is the ventricular septum
dividing wall of tissue including endocardium and myocardium.
what valves does the heart contain
- pulmonic valve
- aortic valve
- bicuspid- mitral
left atrium bicuspid right atrium tricuspid
what is the make up of the valves
the flaps are called cusps and they are attached to the papillary muscles via the chordae tendenae, which stops the valves from inverting
tak about the blood flow of the heart starting with the inferior and superior vena cava
- Deoxygenated blood travels through the inferior and superior vena cava into right atria.
- The right atria contracts sending the blood through the tricuspid valves in to right ventricle.
- This then contracts and sends the blood through the pulmonic valve into the pulmonary arteries.
- it goes to lungs and to oxygenate the blood.
- it then travels via the pulmonary veins to the left atria.
- atria contracts and sends blood through the bicuspid valve in to the ventricle.
- ventricle contracts and sends blood through the aortic valve into the arorta and systemic arteries to carry oxygenated blood to the body.
- the systemic veins and superior and inferior vena cava then take the deoxygenated blood back the right atria.
What is ECS
Electrical conduction system - specialised cardia cells which produce electrical impulse to cause heart to contract.
What is the ECS made up of
- Sino atrial node
- atrio ventricular node
- atrio ventricular bundle - bundle of his
Talk about the Sino atrial node.
- Positioned at the top right atria by the superior vena cava.
- its instability causes it to discharge regular impulses at an intrinsic rate of 60-80 - depolarise
- Acts as a pacemaker to the heart
- Sends impulse across atria and causes the atria to causing it to contract/pump
- after the atria depolarises and relaxes
Talk about the atria ventricular node
- Small bundle of neuromuscular tissue in the wall of the atrial septum.
- It transmits impulse from atria to ventricles
- there is a 0.1 second delay which allows for the atria to relax before the ventricles contract.
- intrinsic rate of 40-60
- Has a secondary pacemaker function
Talk about the atrioventricular bundle/ bundle of his
- This is a mass of specialised fibres that crosses the fibrous ring that separates the atria and the ventricles.
- it divides into 2 branches -left and right bundle brunches at the upper ventricle septum
- it then breaks up into fine microfibres in the myocardium called the purkinje fibres
- this transmits the impulse - depolarises- to the apex in the myocardium causing it to contract and send blood into the pulmonary artery.
- after completion the heart relaxes- repolarisation
talk about the cardiac cycle including times
- atrial systole - 0.1 secs
- ventricular systole - 0.3 secs
- diastole - 0.4 secs
what is blood pressure
its the pressure exerted by blood on the arterial walls.
what is systolic pressure
the force at which the ventricle pumps blood into the aorta.
what is blood pressure recorded in
what is normal systolic pressure in an adult
what is diastolic pressure
the pressure when the heart and blood vessels recoil
what is normal diastolic pressure
what is pulse pressure
the difference between the systolic and diastolic pressure
talk about the order at which vascular pressure decreases
- vena cava
what is cardiac output
the amount of blood expelled from the ventricle in 1 minute.
what is stroke volume
the amount of blood expelled from the heart in each contraction
how do you measure cardiac output
stroke vol x HR
What is the nervous control of the of the heart.
- Autonomic nervous system
- however the mainly controlled by the rate of autorhythmicity.
where is the cardiovascular centre located in the nervous system
In the medulla oblongata
what are the 2 types of nervous controls that regulate heart rate
- parasympathetic- slows it down
- sympathetic - speeds it up
what nerve links the brain to the heart and is it sympathetic or parasympathetic
vagus nerve - parasympathetic
what does the chemoreceptor measure and regulate
it measure the co2 and o2 levels in our body and therefore regulates heart rate
what does the baroreceptor measure and how does it regulate what is measures
it measures blood pressure and alters blood vessels
what is normal heart rate and what is it called if too high and low
- normal heart rate is 60- 100 bmp
- lower than 60 is bradycardia
- higher than 100 is tachycardia
what are the main factors that effect the heart rate
- emotional state
- autonomic nervous system
- baroreceptor reflex
what effects stroke volume
- venous return - body position, skeletal muscle pump, respiratory pump
- strength of myocardium contraction
- blood vol
name all of the blood vessels
what are the layers of the blood vessels
- tunica adventitia - fibrous sheath
- tunica media - elastic fibre and muscles layer
- tunica intime - smooth inner lining of endothelium
talk about the arteries
- carry blood away from the heart
- they are bigger that veins. strong outer coat and thick muscular layer
talk about the arterioles
smaller than arteries and they contract and dilate to control the passage of blood into and out of the capillary bed
Talk about the capillaries
- they are where gas exchange takes and the transfer of nutrients takes place.
- have thin semipermeable walls. single layer if cells.
talk about the venules
smaller than veins. contract and relax to control passage of blood into and out of the capillary bed.
talk about the veins
- thinner walls than capillaries
- carry blood back to the heart
- have valves for to prevent back flow of blood
what is the venous return
rate of blood flow back to the heart.
what does blood do
transports nutrients, o2, hormones, heat, protective substances, clotting factors
what is the composition of blood
- 45 percent solid
- 55 percent liquid
what is the liquid part of the blood made up of
what is the liquid part of the blood made up of
- erythrocytes - rbc
- leucocytes - wbc
- thrombocytes - platelets
what is plasma composed of
- 92 percent water
- the rest is inorganic salts
- plasma proteins
- gases in the solution
- hormones and enzymes
- waste material
Talk about erythrocytes
- red blood cells
- have no nucleus
- great affinity to o2
- contain haemoglobin
- survive for 120 days
- 5 million per cubic mm
- produced in bone marrow
- white blood cells
- have a nucleus
- fight infection
- 8000 per cubic mm
- transparent in colour
- formed in red bone marrow, spleen, liver and lymph glands
talk about thrombocytes
- smaller than rbc
- no nucleus
- essential for blood clotting and control of bleeding
- 250,000 per cubic mm
- survice for 8-11 days
normal blood vol is
- 70ml/kg adults
- 80ml/kg children