The Heart Flashcards
Function of the blood circulatory system
Transport system for food and oxygen into body cells
Move co2 and nitrogenous waste away from body cells
Above is transported via the blood
Open circulatory system
Blood is not confined to the blood vessels
Blood filled spaces/cavities aka HAEMOCOELS
Organs found in haemocoels ——> submerged in blood
Obtain O2 and food from blood by diffusion
Closed circulatory system
Blood is confined to the blood vessels only
[arteries , veins , capillaries ]
Double circulatory system
Blood is pumped from heart along 2 circuits
1] pulmonary circuit - CO2 blood moves from heart to lungs and returns to heart as O2 blood
2] systemic circuit - O2 blood is pumped throughout body and returns to heart as CO2 blood
Aorta
Carries Co2 blood from left ventricle to all parts of body
Superior VC
Carries CO2 blood from upper body parts into right atrium
Right atrium
Receives CO2 blood from superior and inferior VC
Coronary artery
Supplies o2 blood to the muscles of the heart
Inferior VC
Carries CO2 blood from lower parts of body into right atrium
Pulmonary arteries
Carries CO2 blood from rt ventricle into lungs
Pulomonary veins
Carries O2 blood from lungs into left atrium
Left atrium
Receives O2 blood from pulmonary veins from lungs
Coronary vein
Carries co2 blood from heart muscle
Pericardium
Membrane that encloses and protects the heart
Tricuspid valve
Prevents blood from right ventricle from flowing back into right atrium
Tendonous cords
Prevent valve segments from flapping back into atrium
Right ventricle
Co2 blood from here pumped to lungs
Thinner muscle wall
Contraction of this muscular wall forces blood to move from rt atrium to lungs
Semi-lunar valves
Prevents back flow of blood from pulmonary artery into into right ventricle
Bicuspid valves [mitral]
Prevents blood from left ventricle from flowing back into the left atrium
Left ventricle
O2 blood from here is pumped throughout body
Thicker muscular wall
Provides powerful contractions to pump blood from left ventricle to body
Septum
Seperating wall preventing the mixing of o2 blood and co2 blood
Valve
Allows for 4 the movement of blood in one direction
Cardiac cycle
Contractions and relaxations of the heart muscle [heartbeat]
Lub-dub sound of beating heart
Closing of valves as the atrial and ventricular muscles contract
Sino-Atrial Node
Wall of rt atrium has specialised cells which acts as pacemaker
Determines the rate of contraction of atria and ventricles according to needs of body
Atrial Systole
Muscles of atria contract
Tricuspid and Bicuspid valves forced open to allow for blood to flow from atria into ventricles
Duration - 0,1 s
Ventricular Systole
Ventricular muscles contract
Both tricuspid and bicuspid vales Close [LUB SOUND]
Semi-lunar valves of PA and aorta open
CO2 blood from rt ventricle is forced up PÁ and moves to lungs
O2 blood from left ventricle is forced up aorta and moves to all parts of body
Duration - 0,3 s
Atrial and Ventricular diastole
Muscles of atria and ventricles relax
Semi lunar valves in aorta and PÁ close to prevent any back flow of blood [DUB SOUND]
CO2 blood from the VC’s fills rt atrium - O2 blood from PV fills left atrium
Cycle starts again
Duration - 0,4 seconds
Mechanisms controlling the heartbeat and heart rate
Heartbeat controlled by the brain [medulla oblongata]
If medulla does not send Impulse to heart ——> muscles won’t contract and heart won’t beat
Flow diagram representing the mechanism of heartbeat
Co2 concentration high in blood leaving heart via systemic circuit
Chemoreceptors in carotid arteries send impulses to brain
Brain sends impulse to pacemaker of heart to increase the heart beat
More blood flows to lungs and more co2 is expelled
Co2 levels in arterial blood drops to normal and the heartbeat returns to normal
When is a pulse created
When the heart beats and blood moves through the arteries
Blood pressure
Refers to the two pressures measured in the arteries when the muscles of heart contract and relax
Systolic pressure
Heart is pumping is high at 120mm
Diastolic pressure
When the heart is pumping at Normal pressure when heart is at res at 80mm Hg
