transport in animals

Question 1

explain 2 needs for transport systems in multicellular animals

Answer 1

SURFACE AREA TO VOLUME RATIO:
gets smaller as organisms get bigger
diffusion distance gets bigger
METABOLIC RATE:
needs are high as a lot of O2 is needed and food as they produce lots of waste so diffusion over long distances is not enough

Question 2

describe and explain open circulatory systems in animals

Answer 2

blood flows through the body cavity called haemocoel. In transport medium it is under low pressure, comes in direct contact with tissues and cells the transport medium returns to the heart through an open ended vessel

Question 3

insects blood??

Answer 3

gas exchange takes place in the tracheal system
insect blood is called haemolymph - doesnt carry oxygen or carbon dioxide, transports food and nitrogenous waste products

Question 4

describe and explain open circulatory systems in insects

Answer 4

the body cavity is split by a membrane and the heart extends along the length of the thorax and the abdomen of the insect. The haemolymph circulates but steep diffusion gradient cant be maintained

Question 5

what happens in single circulatory system

Answer 5

blood flows through the heart only once per circulation

happens in fish

Question 6

what happens in a double circulatory system

Answer 6

blood passes through the heart twice and around the body circulates around the body and returns

Question 7

describe fully an artery

Answer 7

muscles layer thick
elastic layer thick 
overall wall thick
no valves 
carry blood from the heart to the arterioles

Question 8

describe fully arterioles

Answer 8

muscles layer thick
elastic layer thin
overall wall medium 
valves none 
carry blood from artery to capillaries

Question 9

describe fully capillaries

Answer 9

muscle layer none
elastic layer none
overall wall one cell thin
valves none
provides large exchange surface for tissue fluid and cells

Question 10

describe fully venules

Answer 10

muscle layer very thin
elastic layer none
overall wall medium
valves are present
carry blood from capillaries to veins

Question 11

describe fully veins

Answer 11

muscle layer thin
elastic layer thin
overall wall thin
valves are present
take blood from body to heart

Question 12

describe how tissue fluid is formed and two ways it enters the blood

Answer 12

hydrostatic pressure forces water and small molecules out of the capillaries.large proteins and molecules stay in the blood, therefore it has a negative water potential and is more concentrated so it enters back to the blood by osmosis

Question 13

describe the cardiac cycle

Answer 13

lasts about 0.8 seconds
diastole
systole

Question 14

describe diastole

Answer 14

heart relaxes
the atria and the ventricles fill with blood
volume and pressure increases
pressure in the arteries is at a minimum

Question 15

describe systole

Answer 15

atria contract closely followed by ventricles

pressure dramatically increases and blood is forced out of the right side volume and pressure is low at the end

Question 16

describe the basic rhythm of the heart

Answer 16

a wave of electrical excitation begins in a pacemaker called the sino atrial node causing the atria to contract
electrical activity is picked up by atrio ventricular node and imposes a slight delay before stimulating the bundle of his
made of purkyne fibres
bundle of his splits into 2 branches and conducts the wave of excitation to the apex
at the apex a excitation triggers the contraction of the ventricle

Question 17

what is meant by tachycardia

Answer 17

when the heart beat is very rapid

over 100BPM

Question 18

what is meant by bradycardia

Answer 18

when the heart beat is slow

below 60BPM

Question 19

what is meant by ectopic heartbeat

Answer 19

extra heat beats added that are out of the normal rythm

Question 20

what is meant by atrial fibrillation

Answer 20

abnormal rhythm of heart

Question 21

what causes the heart sounds

Answer 21

heard through a stethoscope

first sound is when blood is forced against the atrio ventricular valves as ventricles contract