L1 Flashcards
Introduction to circulation
Circulation encompasses what organs and fluids? (4)
Lungs
Heart
Kidneys
Blood
Function of circulation (6)
- Supply oxygen, glucose and nutrients to tissues
- Remove waste
- Homeostasis of extracellular fluid (by kidneys)
- Hormone distribution
- Temperature regulation
- Defense against infections
What is perfusion and what does it require?
The flow of blood; a pressure difference
Hypertension leads to _______ because ______.
Hypotension leads to ________ because _______.
Vessel and heart damage; too much perfusion
Syncope (shock); too little perfusion
Right heart –> ____ circulation
Left heart –> ____ circulation
Pulmonary
Systemic
BP=
CO × PR
What occurs during systole in a blood pressure test?
Pressure in blood vessel greater than pressure in cuff so blood vessel opens blood vessel and blood flows (so is heard with the stethoscope).
How is the diastole recorded in a blood pressure test?
After systole is recorded, listen out for when no more sounds are heard. This is the diastolic point.
Outline the journey of blood from aorta to vena cava. (8)
Aorta 》large artery 》small artery 》arteriole 》capillaries 》venule 》vein 》vena cava
Function of aorta (2)
Stretch and recoil
Stores energy
Function of arteries (2)
Distribute blood
Volume adjust
Function of arterioles (2)
Resistance
Set blood pressure and total peripheral resistance
Function of capillaries
Exchange (nutrient, gas, fluids)
Function of venules (2)
Collect blood
Some exchange
Function of veins (3)
Reservoir for blood Muscle pump (using nearby muscle to help blood movement upwards to heart)
Describe the layers of an artery from outside to inside. (3)
Tunica adventitia 》Tunica media (smooth muscle and external elastic layer)》Tunica intima (internal elastic layer and endothelium)
Describe the characteristics of an arteriole. (3)
Little connective tissue
Smooth muscle
Endothelium
Describe the characteristics of a capillary. (1)
Endothelium
Describe the characteristics of a venule. (3)
Connective tissue
Little smooth muscle
Endothelium
Describe the characteristics of a vein. (3)
Connective tissue
Smooth muscle
Endothelium
Which vessels have valves and which don’t to prevent backflow of blood?
Valves = veins
No valves = arteries and capillaries
Pulmonary circulation: right/left ventricle thin/thick walled crescent/circular X-section lungs only/multiple organs variable flow/high flow variable resistance/low resistance
Right Thin Crescent Lungs only High flow Low resistance
Systemic circulation: right/left ventricle thick/thin walled crescent/circular X-section multiple organs/lungs only variable flow/high flow variable resistance/low resistance
Left Thick Circular Multiple organs Variable flow Variable resistance
What is a systole, how are papillary fibres involved and what sound is produced as a result?
Ventricle contraction to eject blood. Papillary fibres prolapse and the AV valves close producing a lub sound.
A diastole is longer than a systole. What is a diastole and what sound is produced?
Ventricle relaxation to fill ventricles with blood. The semilunar valves close producing a dub sound.
What is the apex beat?
During systole, the heart’s apex lunges forward and strikes the chest wall.
Pressure of outflow > pressure of inflow, so valves…
Close
What muscle prevents valve inversion during blood flow?
Chordae tendinae
Which valve deviates from the three-leaflet rule?
Mitral valve (bicuspid valve)
Describe the journey of deoxygenated blood from vena cava. (7)
Vena cava > right atrium > tricuspid valve > right ventricle > pulmonary valve > pulmonary arteries > lungs
Describe the journey of oxygenated blood from pulmonary veins. (6)
Pulmonary veins > left atrium > mitral (bicuspid) valve > left ventricle > aortic valve > body (systemic)
Describe a heart contraction. (5)
External electrical stimulation of myocyte > free intracellular Ca2+ increases (intracell becomes positive and extracell becomes negative) > muscle contracts > Ca2+ removed > muscle relaxes
Kidneys control…(2)
Blood volume
Ion, salts and electrolyte concentration
Describe the filtration system of the kidneys.
Enter afferent arteriole > filtration (of H2O, C6H12O6 and ions through Bowman’s capsule; blood cells and protein remain behind) > reabsorption (of small molecules) > secretion (of excess fluid from peritubular capillaries) > excretion (of excess fluid and small molecules)
Concentrated blood leaves via the ______.
______ goes in via the afferent arteriole.
What enters Bowman’s capsule?
Efferent arteriole
Whole blood
Ultrafiltrate
How does the glomerular filtration rate affect urine production?
Increase in GFR causes increase in fluid movement through tubules
What sounds are listened for during a blood pressure test?
Korotkoff sounds
In terms of filtration rates, a small afferent artery =
Less filtration
What are known as the formed elements within the blood?
Platelets, red blood cells, white blood cells
Blood pressure is determined by blood volume and circulatory capacity. What is circulatory capacity?
This is the space allowed for blood to flow.
What two systems control the kidneys?
Endocrine & autonomic nervous system
An increase in filtration rate at the glomerulus = ___ afferent arteriole and ___ efferent arteriole.
Dilated; Constricted
What fault in the lungs leads to hypoxia, hypoxaemia and anoxia?
Failure of gas exchange
Define ischaemia.
Insufficient blood flow to a region.
Define anoxia.
Complete deprivation of O2 supply to a region.
Define hypoxia.
Insufficient O2 supply to a region.
What bodily malfunctions can lead to ischaemia? (4)
Insufficient pressure generation by the heart, blood vessel clog, vessel constriction, excess loss of blood (eg haemorrhage)
Define hypoxaemia.
Too little O2 supply in the blood.
Where does angina pectoris (chest pain) affect?
Left jawline, left pec and shoulders, and underarm straight down to fingers (spreading across the last two fingers)
Angina pectoris cause and treatment…
Ischaemia of the heart due to a blocked coronary artery.
Nitrates
Myocardial infarction cause and treatment…
Blocked coronary artery causing death in one region in the heart
MONA (morphine, oxygen, nitrates, aspirin)
Heart failure consequences
Insufficient blood around the body, fatigue, oedema, dyspnoea (shortness of breath)
