blood pressure, the heart and thermoregulation 🩸 Flashcards
what is the cardiovascular system do?
it transports nutrients and other materials via the blood to and from various parts of the body
how does the cardiovascular system do its job?
the blood is continusly pumped around the body by the heart through the blood vessles
what are the components of blood?
its a fluid connective tissue made up of plasma[ (30-60%), water, dissolved O2, hormones, proteins and pH buffers]; leucocytes [defend the body against infection and disease]; erythrocytes [haematocrit, the volume of blood thats composed of red blood cells, ~250 million naemoglobin molecules, each protein subunit has 1 haem molecule that binds to one O2 molecule]; and platelets [these play a crutial role in the fomation of blood clots]
what are the site of gas and nutrient exchange?
capilaries
what causes a contraction in the muscle?
an increase in the Ca2+ concentration
what happens when an electrical impulse goes through a myogenic heart?
signalling mechanisms cause the heart to bear within the heart, they’re electrically excitable and generate their own action potentials
the rate and forcefulness of the beating heart can be regulated by the nervous system
they can continue to beat on their own even when they’re dissected out of the body and put into a nutrient bath and even when there aren’t any nerves
the sinoatrial node is found on the posterior wall of the right atrium and when it generates an electrical signal, it rapidly spreads across the atria and causes it to beat
the atria are electrically isolated from the ventricles which means there is the AV node (atrioventricular node)
the electrical sugnal causes the intracellular calcium concentration with the atrial myocytes, the increase in concentration triggers the contraction of the heart
what is an electrocardiogram?
its a way of monitoring the electrical activity of the heart
what is the pulmonary circuit?
the pulmonary circuit is the blood that comes from the right side of the heart to the lungs to be reoxygenated and release CO2
what is blood pressure?
the force that the blood exerts of the walls of the blood vessles
what is a pressure gradient in terms of the cardiovascular system?
its the difference in pressure between the beginning and end of the vessel
blood flows from an area of high pressure to an area of low pressure
when the heart contracts, it exerts pressure on the blood which is the main driving force for flow through a vessle
due to the resistance in the vessle, the pressure drops as blood flows
what is resistance?
its the measure of hindrance or opposition to blood flow through a vessel, caused by friction between the blood and the vessel wall
if resistance of flow increases, its difficult for blood to pass through a vessel and therefore decreases the flow rate
what are the main determinants of resistance?
viscocity of blood
length of the blood vessel
radius of the blood vessel
a slight change in the radius produces a significant change in blood flow
what are arteries?
they carry blood away from the heart
they serve as rapid-transport passageways for blood from the heart to organs
due to their large radius, arteries offer little resistance for the flow of blood
they also act as a pressure resivoir when the heart is relaxing
arterial connective tissue contains collagen fibres and elastin fibres
what are arterioles?
theyre smaller branches of arteries which control blood pressure and tissue blood flow
theyre major resistance vlood vessels ans convert the pulsate systolic to diastolic pressure. pressure swings in the arteries into the non-fluctuating pressue present in the capillaries
the radius of the arteriole can be ajusted to distribute cardiac output among systemic organs, depending on body’s momentary needs; and to help regulate arterial blood pressure
what are capillaries?
they are smaller branches of arterioles and are the smallest of all the vessles across which all exchanges are made with surrounding cells
