cardiovascular Flashcards
3 reasons why large organisms need a transport system
- to ensure effective diffusion
- cells metabolically active; system needs to deliver oxygen, nutrients and remove waste products
- platelets, immune cells and chemical messengers need to move to where they are needed
what 6 things are included in the cardiovascular system
- blood (liquid tissue)
- heart
- arteries
- vein
- capillaries
- lymphatics
where does the right side of the heart pump blood to
- the lungs
where does the left side of the heart pump blood to
- the rest of the body
what are the two systems of the heart called
- pulmonary and systemic
how many chambers does the heart have and what are they called and where are they found
- heart has 4 chambers
- top = atria
- bottom = ventricles
what is the role of atria
- atria receive blood returning from the body (right atrium) and from the lungs (left atrium)
- responsible for pumping blood into ventricles
what is the role of ventricles
- ventricles pump blood out of the heart to the lungs (right ventricle) and rest of body (left ventricle)
what is the cardiac muscle that separates the left and right side of the heart and what is its role
- atrial or ventricular septum
- ensures blood flows in a single direction through the heart
what is the process when deoxygenated blood enters the heart
- returns to heart via superior vena cava or inferior vena cava
- flow into right atrium
- heart contracts blood is forced through tricuspid valve into right ventricle
- blood pumped through pulmonary valve into pulmonary artery
what is process of oxygenated blood
- oxygenated blood comes to left atrium via pulmonary veins
- left atrium pumps blood to left ventricle through bicuspid valve
- contraction of left ventricle blood flows through aortic valve into aorta and rest of body
is the pulmonary system high or low pressure system
- low pressure system as only goes to lungs
what is it termed when heart is relaxing and filling
- diastole
what is systole
- when heart is contracting and pumping
what is contraction of the heart initiated by
- group of cells known as pacemakers
structure of pacemakers
- small, round cells
- contain little or no contractile proteins meaning they do not contribute to the contraction of the heart
what are pacemakers cells responsible for
- generating an action potential
which two regions are pacemakers cells clustered in
- sino - atrial node (SA)
- atrio - ventricular node (AV)
does the SA node have a stable membrane potential and what does this mean
- the cells within the SA have an unstable membrane potential they then generate action potentials 100 times per minute
- SA node cells are tightly electrically coupled to contractile cells (myocytes) via gap junctions therefore the action potential generated by SA node is rapidly passed throughout the atria
- this is the electric trigger which signals myocytes to contract
- once action potential has propagated through the atria, causing atrial contraction it progresses to ventricles
why can action potentials only reach the ventricles by passage through the AV node
- cells within the AV node slow the transmission of action potential
- leading to a delay between atrial and ventricular contraction
- this allows for the blood to full leave atria before ventricles contract
once action potential leaves AV node what happens
- rapidly transmitted to the bottom of the ventricles through conductive cells known as bundle of his and purkinje fibres
- the action potential then travels up through ventricles
where are atriaventricular valves found and purpose
- between atria and ventricles
- prevents blood from going back to the atria when heart contracts
what do semi lunar valves prevent
- prevents back flow of blood into ventricles
what two things do you need to measure blood pressure
- systolic / diastolic
- systolic represents how hard blood is pumping
- diastolic represents resistance within blood vessels
what do the structure of blood vessels depend on
- where they are located
- what pressure they are under
in what way do blood vessels differ
- diameter
- wall thickness
- constituents
what are the three main layers of blood vessels and where are they found
- intrima (inner most lining)
- media (middle layer)
- adventitia (layer of connective tissue outside)
why do capillaries only have intrima
- they need thin walls so exchange can occur
arteries structure
- thick wall
- high amounts of elastic and smooth tissue
- large diameter
- lower resistance
arterioles structure
- smaller arteries
- small diameter
- major role in blood pressure regulation
capillaries structure
- smallest blood vessels
- single tube of endothelial cells
- v close to cells that need oxygen, nutrients and to get rid of waste
- efficient diffusion
- leaky or tight - different capillaries in different parts of the body
- holes in leaky are big enough for cells to come out
venules and veins
- low pressure
- large lumen
- veins return blood to heart
- unidirectional valves (blood under low pressure so valves prevent back flow)
what is the lymphatic system and what is its role
- system of vessels and nodes
- removes interstitial fluid to circulation (fluid that cells sit in)
- lymphatic system plays a role in immunity
- lymph contains lymphocytes
- concentrated in nodes - no. of lymphocytes can be increased and go to site of infection
- tumours can spread to lymph nodes
homeostasis
- receptor - control center - effector
what are the receptors involved in cardiovascular homeostasis
- baro receptor (detect pressure)
- chemoreceptor ( detects changes in chemicals in blood eg oxygen, ph)
where is the control centre in cardiovascular homeostasis
- medula oblongata
what are the effectors
- heart rate
- stroke volume
- vascular tone
what two ways can the heart be controlled
- intrinsic (signals within the heart)
- extrinsic (signals coming from other parts of the body)
what is the frank starling response
- instrinic response
- mechanism of controlling cardiac output
- law states stroke volume increases as the filling of heart with blood increases
- as blood pressure increases the volume of blood increases
extrinsic factors which affect heart rate
- age and exercise
- ions - increased potassium or sodium leads to a reduction in heart rate
- hormones (epinenine, thyroxin)
- nervous stimulation from branches of autonomic nervous system
what is vasoconstriction
- lumen gets smaller - increase blood pressure by reducing blood volume
what is vasodilation
- lumen gets bigger - reduction in blood pressure
how are the cardiovascular and respiratory system linked
- they work together
- chemoreceptors in the aorta, carotid and brain
- constantly measuring oxygen, co2 and ph
- changes in those leads to increased breathing
- heart then beats faster
what is aortic disease
- wall of aorta becomes weakened and bulged due to increased blood pressure
what is peripheral artery disease
- affects blood vessels other than aorta and coronary heart vessels
what is a stoke and transient ischaemic attack
- bleed or clotting in brain
how can a heart attack happen
- when blood vessels supplying heart become narrowed and not enough oxygen reaching heart and heart tissue begins to die
what is atherosclerosis and blood clots
- blood vessels become obstructed - arteries becomes narrowed as fat deposited
- blood clots form in body preventing blood getting to certain positions
what factors of lifestyle lead to risk factors for cardiovascular disease
- smoking, weight, diet
- family history and ethnic background
- age
- diabetes - twice as likely to have hypertension, obesity and low activity - more likely to have a poor lipid profile and have low lipid density
what is hypertension
- blood pressure always higher
- damages arteries therefore increase deposition of fat increasing risk of aneurysm
- heart has to work harder therefore increase risk of haemorrhage stroke
what are therapeutic agents and examples
- help fight high blood pressure and cardiovascular disease
; renin - angiotensin
; anticoagulants - reduces clotting
; beta - adrenergic blocking agents - reduces interferes with nervous stimulation of heart
; ca channel blockers - causes blood vessels to dilate increasing volume, decreasing pressure and heart rate
; statins - cholesterol lowered drugs - reduce bad cholesterol and improves lipid profile
