The Heart

Question 1

Function of the blood circulatory system

Answer 1

Transport system for food and oxygen into body cells
Move co2 and nitrogenous waste away from body cells
Above is transported via the blood

Question 2

Open circulatory system

Answer 2

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

Question 3

Closed circulatory system

Answer 3

Blood is confined to the blood vessels only

[arteries , veins , capillaries ]

Question 4

Double circulatory system

Answer 4

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

Question 5

Aorta

Answer 5

Carries Co2 blood from left ventricle to all parts of body

Question 6

Superior VC

Answer 6

Carries CO2 blood from upper body parts into right atrium

Question 7

Right atrium

Answer 7

Receives CO2 blood from superior and inferior VC

Question 8

Coronary artery

Answer 8

Supplies o2 blood to the muscles of the heart

Question 9

Inferior VC

Answer 9

Carries CO2 blood from lower parts of body into right atrium

Question 10

Pulmonary arteries

Answer 10

Carries CO2 blood from rt ventricle into lungs

Question 11

Pulomonary veins

Answer 11

Carries O2 blood from lungs into left atrium

Question 12

Left atrium

Answer 12

Receives O2 blood from pulmonary veins from lungs

Question 13

Coronary vein

Answer 13

Carries co2 blood from heart muscle

Question 14

Pericardium

Answer 14

Membrane that encloses and protects the heart

Question 15

Tricuspid valve

Answer 15

Prevents blood from right ventricle from flowing back into right atrium

Question 16

Tendonous cords

Answer 16

Prevent valve segments from flapping back into atrium

Question 17

Right ventricle

Answer 17

Co2 blood from here pumped to lungs

Question 18

Thinner muscle wall

Answer 18

Contraction of this muscular wall forces blood to move from rt atrium to lungs

Question 19

Semi-lunar valves

Answer 19

Prevents back flow of blood from pulmonary artery into into right ventricle

Question 20

Bicuspid valves [mitral]

Answer 20

Prevents blood from left ventricle from flowing back into the left atrium

Question 21

Left ventricle

Answer 21

O2 blood from here is pumped throughout body

Question 22

Thicker muscular wall

Answer 22

Provides powerful contractions to pump blood from left ventricle to body

Question 23

Septum

Answer 23

Seperating wall preventing the mixing of o2 blood and co2 blood

Question 24

Valve

Answer 24

Allows for 4 the movement of blood in one direction

Question 25

Cardiac cycle

Answer 25

Contractions and relaxations of the heart muscle [heartbeat]

Question 26

Lub-dub sound of beating heart

Answer 26

Closing of valves as the atrial and ventricular muscles contract

Question 27

Sino-Atrial Node

Answer 27

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

Question 28

Atrial Systole

Answer 28

Muscles of atria contract Tricuspid and Bicuspid valves forced open to allow for blood to flow from atria into ventricles Duration - 0,1 s

Question 29

Ventricular Systole

Answer 29

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

Question 30

Atrial and Ventricular diastole

Answer 30

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

Question 31

Mechanisms controlling the heartbeat and heart rate

Answer 31

Heartbeat controlled by the brain [medulla oblongata] If medulla does not send Impulse to heart ——> muscles won’t contract and heart won’t beat

Question 32

Flow diagram representing the mechanism of heartbeat

Answer 32

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

Question 33

When is a pulse created

Answer 33

When the heart beats and blood moves through the arteries

Question 34

Blood pressure

Answer 34

Refers to the two pressures measured in the arteries when the muscles of heart contract and relax

Question 35

Systolic pressure

Answer 35

Heart is pumping is high at 120mm

Question 36

Diastolic pressure

Answer 36

When the heart is pumping at Normal pressure when heart is at res at 80mm Hg