PMT Animal tissues, organs and systems part 1

what is the heart

an organ that pumps blood around the body

what is the purpose of the circulatory system

carries oxygen and other useful substances to bodily tissues and removes waste substances

how does the double circulatory system work

one pathway carries blood from the heart to the lungs where the gaseous exchange of oxygen and carbon dioxide take place

one pathway carries blood from the heart to the tissues

where does blood pumped by the right ventricle go

the lungs

where does the blood pumped by the left ventricle go

body tissues

why is the double circulatory system important

it makes the circulatory system more efficient - for example oxygenated blood can be pumped around the body at a higher pressure by the left ventricle

why is the wall of the left ventricle thicker

the left ventricle has to pump blood at a higher pressure around the whole body

what are the four main blood vessels associated with the heart

aorta

pulmonary vein

vena cava

pulmonary artery

what is the purpose of valves in the heart

prevent backflow of blood

what is the purpose of coronary arteries

supply the heart muscle with oxygenated blood

what is the approximate value of the natural resting heart rate

70 beats per minute

how is the heat rate controlled

by a group of cells in the right atrium which act as a pacemaker

they release waves of electrical activity which cause the heart muscle to contract

how can abnormal heart rhythm be treated

using an artificial pacemaker which sends out electrical signals to correct the hearts rhythm

what are the three types of blood vessel in the body

arteries

veins

capillaries

how are arteries adapted for their function

function: carry blood away from the heart

thick muscle layer adds strength to resist high pressure

thick elastic layer allows arteries to stretch and recoil in order to withstand high pressure

how are veins adapted to their function

function: carry blood towards the heart

wide lumen which enables low pressure

valves to prevent backflow of blood

how are capillaries adapted for their function

function: enable transfer of substances between the blood and tissues

walls are one cell thick for a short diffusion path

permeable walls so substances can diffuse across

narrow lumen so blood moves slowly so more time for diffusion

what is the function of the aorta

carries oxygenated blood from the heart to the body

what is the function of the pulmonary vein

carries oxygenated blood from the lungs to the heart

what is the function of the vena cava

carries deoxygenated blood from the body to the heart

what is the function of the pulmonary artery

carries deoxygenated blood from the heart to the lungs