!! the heart

Question 1

what type of circulatory system do humans have

what is the benefit

Answer 1

double circulatory system

benefit: blood passes through the heart twice so can travel rapidly to body cells delivering the oxygen they need for respirateion

Question 2

what is the heart and what does it do

Answer 2

an organ consisting of mainly muscle tissues

pumps blood around the body

Question 3

how many chambers does the heart have

what are they called

where are they located on a diagram

Answer 3

4 chambers

right atrium (top left)

right ventricle (bottom left)

left atrium (top right)

left ventricle (bottom right)

Question 4

what is the vena cava and what does it do

Answer 4

vena cava is a large vein

brings deoxygenated blood from the body to the heart

Question 5

what happens in the pulmonary artery

Answer 5

deoxygenated blood passes from the heart to the lungs

where it collects oxygen

Question 6

what happens in the pulmonary vein

Answer 6

oxygenated blood passes from the lungs to the heart

Question 7

what happens in the aorta

Answer 7

oxygenated blood is pumped from the heart to the body

Question 8

what happens when blood enters the left and right atriums

Answer 8

the atriums contract blood is forced into the ventricles

ventricles then contract and force blood out of the heart

Question 9

what do valves to

Answer 9

stop blood from flowing backwards into the atria when the ventricles contract

forced open when the atria contract to allow blood to pass to the ventricles

Question 10

why does the left side of the heart have a thicker muscular wall than the right side

Answer 10

the left ventricle pumps blood around the entire body so needs to provide a greater force

whereas the right ventricle only pumps blood to the lungs

Question 11

what are the coronary arteries

Answer 11

blood vessels

Question 12

what do the coronary arteries do

Answer 12

branch out of the aorta and spread out into the heart muscle

purpose is to provide oxygen to the muscle cells of the heart

Question 13

where is the natural resting heart rate controlled

Answer 13

group of cells in the right atrium called the pacemarker

Question 14

what happens if someone’s natural pacemaker isn’t working properly

Answer 14

doctors can implant an artificial pacemaker

a small electrical device that senses irregularities in the heart rate and sends electrical signals to the heart muscle to trigger it to beat in a regular pattern

Question 15

what do arteries do

how are they adapted

Answer 15

carry very high pressure blood from the heart to the organs in the body, in surges every time the heart beats (our pulse)

very thick walls to withstand pressure

also contain elastic fibres which stretch when the surge of blood passes through them and recoil inbetween surges, which keeps the blood moving

Question 16

what happens when blood passes through the capillaries

Answer 16

substances such as glucose and oxygen diffuse from the blood to the cells

and carbon dioxide diffuses from the cells back to the blood

Question 17

how are capillaries adapted

Answer 17

very thin walls so the diffusion path is very short

this allows the substances to diffuse rapidly between the blood and the body cells

Question 18

how does the blood from the organs (body) get back to the heart

Answer 18

through veins

lost pressure travelling around the body so now travelling slowly at low pressure

blood could stop or even flow backwards

Question 19

what is the structure of veins

Answer 19

thin walls as blood travels through them at a low pressure

many contain valves to stop blood flowing backwards

when blood flowing in the correct direction, valves open

start flowing in incorrect direction: valves shut